| Message ID | 20200414025154.27283-3-takahiro.akashi@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | efi_loader: add secure boot support | expand |
On 2020-04-14 04:51, AKASHI Takahiro wrote: > In this commit, implemented are a couple of helper functions which will be > used to materialize variable authentication as well as image authentication > in later patches. > > Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org> > --- > include/efi_api.h | 87 +++++ > include/efi_loader.h | 72 ++++ > lib/efi_loader/Makefile | 1 + > lib/efi_loader/efi_signature.c | 583 +++++++++++++++++++++++++++++++++ > 4 files changed, 743 insertions(+) > create mode 100644 lib/efi_loader/efi_signature.c > > diff --git a/include/efi_api.h b/include/efi_api.h > index 1c40ffc4f56c..77d6bf2660b9 100644 > --- a/include/efi_api.h > +++ b/include/efi_api.h > @@ -18,6 +18,7 @@ > > #include <efi.h> > #include <charset.h> > +#include <pe.h> > > #ifdef CONFIG_EFI_LOADER > #include <asm/setjmp.h> > @@ -329,6 +330,10 @@ struct efi_runtime_services { > EFI_GUID(0x8be4df61, 0x93ca, 0x11d2, 0xaa, 0x0d, \ > 0x00, 0xe0, 0x98, 0x03, 0x2b, 0x8c) > > +#define EFI_IMAGE_SECURITY_DATABASE_GUID \ > + EFI_GUID(0xd719b2cb, 0x3d3a, 0x4596, 0xa3, 0xbc, \ > + 0xda, 0xd0, 0x0e, 0x67, 0x65, 0x6f) > + > #define EFI_FDT_GUID \ > EFI_GUID(0xb1b621d5, 0xf19c, 0x41a5, \ > 0x83, 0x0b, 0xd9, 0x15, 0x2c, 0x69, 0xaa, 0xe0) > @@ -1682,4 +1687,86 @@ struct efi_load_file_protocol { > #define LAST_ATTEMPT_STATUS_ERROR_UNSUCCESSFUL_VENDOR_RANGE_MIN 0x00001000 > #define LAST_ATTEMPT_STATUS_ERROR_UNSUCCESSFUL_VENDOR_RANGE_MAX 0x00004000 > > +/* Certificate types in signature database */ > +#define EFI_CERT_SHA256_GUID \ > + EFI_GUID(0xc1c41626, 0x504c, 0x4092, 0xac, 0xa9, \ > + 0x41, 0xf9, 0x36, 0x93, 0x43, 0x28) > +#define EFI_CERT_RSA2048_GUID \ > + EFI_GUID(0x3c5766e8, 0x269c, 0x4e34, 0xaa, 0x14, \ > + 0xed, 0x77, 0x6e, 0x85, 0xb3, 0xb6) > +#define EFI_CERT_X509_GUID \ > + EFI_GUID(0xa5c059a1, 0x94e4, 0x4aa7, 0x87, 0xb5, \ > + 0xab, 0x15, 0x5c, 0x2b, 0xf0, 0x72) > +#define EFI_CERT_X509_SHA256_GUID \ > + EFI_GUID(0x3bd2a492, 0x96c0, 0x4079, 0xb4, 0x20, \ > + 0xfc, 0xf9, 0x8e, 0xf1, 0x03, 0xed) > +#define EFI_CERT_TYPE_PKCS7_GUID \ > + EFI_GUID(0x4aafd29d, 0x68df, 0x49ee, 0x8a, 0xa9, \ > + 0x34, 0x7d, 0x37, 0x56, 0x65, 0xa7) > + > +/** > + * win_certificate_uefi_guid - A certificate that encapsulates > + * a GUID-specific signature > + * > + * @hdr: Windows certificate header > + * @cert_type: Certificate type > + * @cert_data: Certificate data > + */ > +struct win_certificate_uefi_guid { > + WIN_CERTIFICATE hdr; > + efi_guid_t cert_type; > + u8 cert_data[]; > +} __attribute__((__packed__)); > + > +/** > + * efi_variable_authentication_2 - A time-based authentication method > + * descriptor > + * > + * This structure describes an authentication information for > + * a variable with EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS > + * and should be included as part of a variable's value. > + * Only EFI_CERT_TYPE_PKCS7_GUID is accepted. > + * > + * @time_stamp: Descriptor's time stamp > + * @auth_info: Authentication info > + */ > +struct efi_variable_authentication_2 { > + struct efi_time time_stamp; > + struct win_certificate_uefi_guid auth_info; > +} __attribute__((__packed__)); > + > +/** > + * efi_signature_data - A format of signature > + * > + * This structure describes a single signature in signature database. > + * > + * @signature_owner: Signature owner > + * @signature_data: Signature data > + */ > +struct efi_signature_data { > + efi_guid_t signature_owner; > + u8 signature_data[]; Please, use [0]. > +} __attribute__((__packed__)); > + > +/** > + * efi_signature_list - A format of signature database > + * > + * This structure describes a list of signatures with the same type. > + * An authenticated variable's value is a concatenation of one or more > + * efi_signature_list's. > + * > + * @signature_type: Signature type > + * @signature_list_size: Size of signature list > + * @signature_header_size: Size of signature header > + * @signature_size: Size of signature > + */ > +struct efi_signature_list { > + efi_guid_t signature_type; > + u32 signature_list_size; > + u32 signature_header_size; > + u32 signature_size; > +/* u8 signature_header[signature_header_size]; */ > +/* struct efi_signature_data signatures[...][signature_size]; */ > +} __attribute__((__packed__)); > + > #endif > diff --git a/include/efi_loader.h b/include/efi_loader.h > index 3f2792892f34..8cf85d2fb7e2 100644 > --- a/include/efi_loader.h > +++ b/include/efi_loader.h > @@ -26,6 +26,7 @@ static inline void *guidcpy(void *dst, const void *src) > #if CONFIG_IS_ENABLED(EFI_LOADER) > > #include <linux/list.h> > +#include <linux/oid_registry.h> > > /* Maximum number of configuration tables */ > #define EFI_MAX_CONFIGURATION_TABLES 16 > @@ -178,6 +179,11 @@ extern const efi_guid_t efi_guid_hii_config_routing_protocol; > extern const efi_guid_t efi_guid_hii_config_access_protocol; > extern const efi_guid_t efi_guid_hii_database_protocol; > extern const efi_guid_t efi_guid_hii_string_protocol; > +/* GUIDs for authentication */ > +extern const efi_guid_t efi_guid_image_security_database; > +extern const efi_guid_t efi_guid_sha256; > +extern const efi_guid_t efi_guid_cert_x509; > +extern const efi_guid_t efi_guid_cert_x509_sha256; > > /* GUID of RNG protocol */ > extern const efi_guid_t efi_guid_rng_protocol; > @@ -680,6 +686,72 @@ void efi_deserialize_load_option(struct efi_load_option *lo, u8 *data); > unsigned long efi_serialize_load_option(struct efi_load_option *lo, u8 **data); > efi_status_t efi_bootmgr_load(efi_handle_t *handle); > > +#ifdef CONFIG_EFI_SECURE_BOOT > +#include <image.h> > + > +/** > + * efi_image_regions - A list of memory regions > + * > + * @max: Maximum number of regions > + * @num: Number of regions > + * @reg: array of regions > + */ > +struct efi_image_regions { > + int max; > + int num; > + struct image_region reg[]; > +}; > + > +/** > + * efi_sig_data - A decoded data of struct efi_signature_data > + * > + * This structure represents an internal form of signature in > + * signature database. A listed list may represent a signature list. > + * > + * @next: Pointer to next entry > + * @onwer: Signature owner > + * @data: Pointer to signature data > + * @size: Size of signature data > + */ > +struct efi_sig_data { > + struct efi_sig_data *next; > + efi_guid_t owner; > + void *data; > + size_t size; > +}; > + > +/** > + * efi_signature_store - A decoded data of signature database > + * > + * This structure represents an internal form of signature database. > + * > + * @next: Pointer to next entry > + * @sig_type: Signature type > + * @sig_data_list: Pointer to signature list > + */ > +struct efi_signature_store { > + struct efi_signature_store *next; > + efi_guid_t sig_type; > + struct efi_sig_data *sig_data_list; > +}; > + > +struct x509_certificate; > +struct pkcs7_message; > + > +bool efi_signature_verify_cert(struct x509_certificate *cert, > + struct efi_signature_store *dbx); > +bool efi_signature_verify_signers(struct pkcs7_message *msg, > + struct efi_signature_store *dbx); > +bool efi_signature_verify_with_sigdb(struct efi_image_regions *regs, > + struct pkcs7_message *msg, > + struct efi_signature_store *db, > + struct x509_certificate **cert); > + > +efi_status_t efi_image_region_add(struct efi_image_regions *regs, > + const void *start, const void *end, > + int nocheck); > +#endif /* CONFIG_EFI_SECURE_BOOT */ > + > #else /* CONFIG_IS_ENABLED(EFI_LOADER) */ > > /* Without CONFIG_EFI_LOADER we don't have a runtime section, stub it out */ > diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile > index 9b3b70447336..eff3c25ec301 100644 > --- a/lib/efi_loader/Makefile > +++ b/lib/efi_loader/Makefile > @@ -44,3 +44,4 @@ obj-$(CONFIG_GENERATE_ACPI_TABLE) += efi_acpi.o > obj-$(CONFIG_GENERATE_SMBIOS_TABLE) += efi_smbios.o > obj-$(CONFIG_EFI_RNG_PROTOCOL) += efi_rng.o > obj-$(CONFIG_EFI_LOAD_FILE2_INITRD) += efi_load_initrd.o > +obj-y += efi_signature.o > diff --git a/lib/efi_loader/efi_signature.c b/lib/efi_loader/efi_signature.c > new file mode 100644 > index 000000000000..23dac94c0593 > --- /dev/null > +++ b/lib/efi_loader/efi_signature.c > @@ -0,0 +1,583 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +/* > + * Copyright (c) 2018 Patrick Wildt <patrick at blueri.se> > + * Copyright (c) 2019 Linaro Limited, Author: AKASHI Takahiro > + */ > + > +#include <common.h> > +#include <charset.h> > +#include <efi_loader.h> > +#include <image.h> > +#include <hexdump.h> > +#include <malloc.h> > +#include <pe.h> You just added pe.h to efi_api.h which is included in efi_loader.h. Please, avoid adding the includes twice. > +#include <linux/compat.h> > +#include <linux/oid_registry.h> > +#include <u-boot/rsa.h> > +#include <u-boot/sha256.h> > +/* > + * avoid duplicated inclusion: Why don't you fix the lib/crypto/x509_parser.h that you created? Just add the missing #ifdef _X509_PARSER_H #define _X509_PARSER_H #endif /* _X509_PARSER_H */ Same problem in pkcs7_parser.h. > + * #include "../lib/crypto/x509_parser.h" > + */ If you patch is working I see no reason to add the comment here. > +#include "../lib/crypto/pkcs7_parser.h" Why is pkcs7_parser.h in lib/ and not in include/? I would prefer to avoid relative paths. I will remove the superfluous comment and include when merging. The rest can be fixed later. Best regards Heinrich > + > +const efi_guid_t efi_guid_image_security_database = > + EFI_IMAGE_SECURITY_DATABASE_GUID; > +const efi_guid_t efi_guid_sha256 = EFI_CERT_SHA256_GUID; > +const efi_guid_t efi_guid_cert_rsa2048 = EFI_CERT_RSA2048_GUID; > +const efi_guid_t efi_guid_cert_x509 = EFI_CERT_X509_GUID; > +const efi_guid_t efi_guid_cert_x509_sha256 = EFI_CERT_X509_SHA256_GUID; > + > +#ifdef CONFIG_EFI_SECURE_BOOT > + > +/** > + * efi_hash_regions - calculate a hash value > + * @regs: List of regions > + * @hash: Pointer to a pointer to buffer holding a hash value > + * @size: Size of buffer to be returned > + * > + * Calculate a sha256 value of @regs and return a value in @hash. > + * > + * Return: true on success, false on error > + */ > +static bool efi_hash_regions(struct efi_image_regions *regs, void **hash, > + size_t *size) > +{ > + *size = 0; > + *hash = calloc(1, SHA256_SUM_LEN); > + if (!*hash) { > + debug("Out of memory\n"); > + return false; > + } > + *size = SHA256_SUM_LEN; > + > + hash_calculate("sha256", regs->reg, regs->num, *hash); > +#ifdef DEBUG > + debug("hash calculated:\n"); > + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1, > + *hash, SHA256_SUM_LEN, false); > +#endif > + > + return true; > +} > + > +/** > + * efi_hash_msg_content - calculate a hash value of contentInfo > + * @msg: Signature > + * @hash: Pointer to a pointer to buffer holding a hash value > + * @size: Size of buffer to be returned > + * > + * Calculate a sha256 value of contentInfo in @msg and return a value in @hash. > + * > + * Return: true on success, false on error > + */ > +static bool efi_hash_msg_content(struct pkcs7_message *msg, void **hash, > + size_t *size) > +{ > + struct image_region regtmp; > + > + *size = 0; > + *hash = calloc(1, SHA256_SUM_LEN); > + if (!*hash) { > + debug("Out of memory\n"); > + free(msg); > + return false; > + } > + *size = SHA256_SUM_LEN; > + > + regtmp.data = msg->data; > + regtmp.size = msg->data_len; > + > + hash_calculate("sha256", ®tmp, 1, *hash); > +#ifdef DEBUG > + debug("hash calculated based on contentInfo:\n"); > + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1, > + *hash, SHA256_SUM_LEN, false); > +#endif > + > + return true; > +} > + > +/** > + * efi_signature_verify - verify a signature with a certificate > + * @regs: List of regions to be authenticated > + * @signed_info: Pointer to PKCS7's signed_info > + * @cert: x509 certificate > + * > + * Signature pointed to by @signed_info against image pointed to by @regs > + * is verified by a certificate pointed to by @cert. > + * @signed_info holds a signature, including a message digest which is to be > + * compared with a hash value calculated from @regs. > + * > + * Return: true if signature is verified, false if not > + */ > +static bool efi_signature_verify(struct efi_image_regions *regs, > + struct pkcs7_message *msg, > + struct pkcs7_signed_info *ps_info, > + struct x509_certificate *cert) > +{ > + struct image_sign_info info; > + struct image_region regtmp[2]; > + void *hash; > + size_t size; > + char c; > + bool verified; > + > + debug("%s: Enter, %p, %p, %p(issuer: %s, subject: %s)\n", __func__, > + regs, ps_info, cert, cert->issuer, cert->subject); > + > + verified = false; > + > + memset(&info, '\0', sizeof(info)); > + info.padding = image_get_padding_algo("pkcs-1.5"); > + /* > + * Note: image_get_[checksum|crypto]_algo takes an string > + * argument like "<checksum>,<crypto>" > + * TODO: support other hash algorithms > + */ > + if (!strcmp(ps_info->sig->hash_algo, "sha1")) { > + info.checksum = image_get_checksum_algo("sha1,rsa2048"); > + info.name = "sha1,rsa2048"; > + } else if (!strcmp(ps_info->sig->hash_algo, "sha256")) { > + info.checksum = image_get_checksum_algo("sha256,rsa2048"); > + info.name = "sha256,rsa2048"; > + } else { > + debug("unknown msg digest algo: %s\n", ps_info->sig->hash_algo); > + goto out; > + } > + info.crypto = image_get_crypto_algo(info.name); > + > + info.key = cert->pub->key; > + info.keylen = cert->pub->keylen; > + > + /* verify signature */ > + debug("%s: crypto: %s, signature len:%x\n", __func__, > + info.name, ps_info->sig->s_size); > + if (ps_info->aa_set & (1UL << sinfo_has_message_digest)) { > + debug("%s: RSA verify authentication attribute\n", __func__); > + /* > + * NOTE: This path will be executed only for > + * PE image authentication > + */ > + > + /* check if hash matches digest first */ > + debug("checking msg digest first, len:0x%x\n", > + ps_info->msgdigest_len); > + > +#ifdef DEBUG > + debug("hash in database:\n"); > + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1, > + ps_info->msgdigest, ps_info->msgdigest_len, > + false); > +#endif > + /* against contentInfo first */ > + if ((msg->data && efi_hash_msg_content(msg, &hash, &size)) || > + /* for signed image */ > + efi_hash_regions(regs, &hash, &size)) { > + /* for authenticated variable */ > + if (ps_info->msgdigest_len != size || > + memcmp(hash, ps_info->msgdigest, size)) { > + debug("Digest doesn't match\n"); > + free(hash); > + goto out; > + } > + > + free(hash); > + } else { > + debug("Digesting image failed\n"); > + goto out; > + } > + > + /* against digest */ > + c = 0x31; > + regtmp[0].data = &c; > + regtmp[0].size = 1; > + regtmp[1].data = ps_info->authattrs; > + regtmp[1].size = ps_info->authattrs_len; > + > + if (!rsa_verify(&info, regtmp, 2, > + ps_info->sig->s, ps_info->sig->s_size)) > + verified = true; > + } else { > + debug("%s: RSA verify content data\n", __func__); > + /* against all data */ > + if (!rsa_verify(&info, regs->reg, regs->num, > + ps_info->sig->s, ps_info->sig->s_size)) > + verified = true; > + } > + > +out: > + debug("%s: Exit, verified: %d\n", __func__, verified); > + return verified; > +} > + > +/** > + * efi_signature_verify_with_list - verify a signature with signature list > + * @regs: List of regions to be authenticated > + * @msg: Signature > + * @signed_info: Pointer to PKCS7's signed_info > + * @siglist: Signature list for certificates > + * @valid_cert: x509 certificate that verifies this signature > + * > + * Signature pointed to by @signed_info against image pointed to by @regs > + * is verified by signature list pointed to by @siglist. > + * Signature database is a simple concatenation of one or more > + * signature list(s). > + * > + * Return: true if signature is verified, false if not > + */ > +static > +bool efi_signature_verify_with_list(struct efi_image_regions *regs, > + struct pkcs7_message *msg, > + struct pkcs7_signed_info *signed_info, > + struct efi_signature_store *siglist, > + struct x509_certificate **valid_cert) > +{ > + struct x509_certificate *cert; > + struct efi_sig_data *sig_data; > + bool verified = false; > + > + debug("%s: Enter, %p, %p, %p, %p\n", __func__, > + regs, signed_info, siglist, valid_cert); > + > + if (!signed_info) { > + void *hash; > + size_t size; > + > + debug("%s: unsigned image\n", __func__); > + /* > + * verify based on calculated hash value > + * TODO: support other hash algorithms > + */ > + if (guidcmp(&siglist->sig_type, &efi_guid_sha256)) { > + debug("Digest algorithm is not supported: %pUl\n", > + &siglist->sig_type); > + goto out; > + } > + > + if (!efi_hash_regions(regs, &hash, &size)) { > + debug("Digesting unsigned image failed\n"); > + goto out; > + } > + > + /* go through the list */ > + for (sig_data = siglist->sig_data_list; sig_data; > + sig_data = sig_data->next) { > +#ifdef DEBUG > + debug("Msg digest in database:\n"); > + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1, > + sig_data->data, sig_data->size, false); > +#endif > + if ((sig_data->size == size) && > + !memcmp(sig_data->data, hash, size)) { > + verified = true; > + free(hash); > + goto out; > + } > + } > + free(hash); > + goto out; > + } > + > + debug("%s: signed image\n", __func__); > + if (guidcmp(&siglist->sig_type, &efi_guid_cert_x509)) { > + debug("Signature type is not supported: %pUl\n", > + &siglist->sig_type); > + goto out; > + } > + > + /* go through the list */ > + for (sig_data = siglist->sig_data_list; sig_data; > + sig_data = sig_data->next) { > + /* TODO: support owner check based on policy */ > + > + cert = x509_cert_parse(sig_data->data, sig_data->size); > + if (IS_ERR(cert)) { > + debug("Parsing x509 certificate failed\n"); > + goto out; > + } > + > + verified = efi_signature_verify(regs, msg, signed_info, cert); > + > + if (verified) { > + if (valid_cert) > + *valid_cert = cert; > + else > + x509_free_certificate(cert); > + break; > + } > + x509_free_certificate(cert); > + } > + > +out: > + debug("%s: Exit, verified: %d\n", __func__, verified); > + return verified; > +} > + > +/** > + * efi_signature_verify_with_sigdb - verify a signature with db > + * @regs: List of regions to be authenticated > + * @msg: Signature > + * @db: Signature database for trusted certificates > + * @cert: x509 certificate that verifies this signature > + * > + * Signature pointed to by @msg against image pointed to by @regs > + * is verified by signature database pointed to by @db. > + * > + * Return: true if signature is verified, false if not > + */ > +bool efi_signature_verify_with_sigdb(struct efi_image_regions *regs, > + struct pkcs7_message *msg, > + struct efi_signature_store *db, > + struct x509_certificate **cert) > +{ > + struct pkcs7_signed_info *info; > + struct efi_signature_store *siglist; > + bool verified = false; > + > + debug("%s: Enter, %p, %p, %p, %p\n", __func__, regs, msg, db, cert); > + > + if (!db) > + goto out; > + > + if (!db->sig_data_list) > + goto out; > + > + /* for unsigned image */ > + if (!msg) { > + debug("%s: Verify unsigned image with db\n", __func__); > + for (siglist = db; siglist; siglist = siglist->next) > + if (efi_signature_verify_with_list(regs, NULL, NULL, > + siglist, cert)) { > + verified = true; > + goto out; > + } > + > + goto out; > + } > + > + /* for signed image or variable */ > + debug("%s: Verify signed image with db\n", __func__); > + for (info = msg->signed_infos; info; info = info->next) { > + debug("Signed Info: digest algo: %s, pkey algo: %s\n", > + info->sig->hash_algo, info->sig->pkey_algo); > + > + for (siglist = db; siglist; siglist = siglist->next) { > + if (efi_signature_verify_with_list(regs, msg, info, > + siglist, cert)) { > + verified = true; > + goto out; > + } > + } > + } > + > +out: > + debug("%s: Exit, verified: %d\n", __func__, verified); > + return verified; > +} > + > +/** > + * efi_search_siglist - search signature list for a certificate > + * @cert: x509 certificate > + * @siglist: Signature list > + * @revoc_time: Pointer to buffer for revocation time > + * > + * Search signature list pointed to by @siglist and find a certificate > + * pointed to by @cert. > + * If found, revocation time that is specified in signature database is > + * returned in @revoc_time. > + * > + * Return: true if certificate is found, false if not > + */ > +static bool efi_search_siglist(struct x509_certificate *cert, > + struct efi_signature_store *siglist, > + time64_t *revoc_time) > +{ > + struct image_region reg[1]; > + void *hash = NULL, *msg = NULL; > + struct efi_sig_data *sig_data; > + bool found = false; > + > + /* can be null */ > + if (!siglist->sig_data_list) > + return false; > + > + if (guidcmp(&siglist->sig_type, &efi_guid_cert_x509_sha256)) { > + /* TODO: other hash algos */ > + debug("Certificate's digest type is not supported: %pUl\n", > + &siglist->sig_type); > + goto out; > + } > + > + /* calculate hash of TBSCertificate */ > + msg = calloc(1, SHA256_SUM_LEN); > + if (!msg) { > + debug("Out of memory\n"); > + goto out; > + } > + > + hash = calloc(1, SHA256_SUM_LEN); > + if (!hash) { > + debug("Out of memory\n"); > + goto out; > + } > + > + reg[0].data = cert->tbs; > + reg[0].size = cert->tbs_size; > + hash_calculate("sha256", reg, 1, msg); > + > + /* go through signature list */ > + for (sig_data = siglist->sig_data_list; sig_data; > + sig_data = sig_data->next) { > + /* > + * struct efi_cert_x509_sha256 { > + * u8 tbs_hash[256/8]; > + * time64_t revocation_time; > + * }; > + */ > + if ((sig_data->size == SHA256_SUM_LEN) && > + !memcmp(sig_data->data, hash, SHA256_SUM_LEN)) { > + memcpy(revoc_time, sig_data->data + SHA256_SUM_LEN, > + sizeof(*revoc_time)); > + found = true; > + goto out; > + } > + } > + > +out: > + free(hash); > + free(msg); > + > + return found; > +} > + > +/** > + * efi_signature_verify_cert - verify a certificate with dbx > + * @cert: x509 certificate > + * @dbx: Signature database > + * > + * Search signature database pointed to by @dbx and find a certificate > + * pointed to by @cert. > + * This function is expected to be used against "dbx". > + * > + * Return: true if a certificate is not rejected, false otherwise. > + */ > +bool efi_signature_verify_cert(struct x509_certificate *cert, > + struct efi_signature_store *dbx) > +{ > + struct efi_signature_store *siglist; > + time64_t revoc_time; > + bool found = false; > + > + debug("%s: Enter, %p, %p\n", __func__, dbx, cert); > + > + if (!cert) > + return false; > + > + for (siglist = dbx; siglist; siglist = siglist->next) { > + if (efi_search_siglist(cert, siglist, &revoc_time)) { > + /* TODO */ > + /* compare signing time with revocation time */ > + > + found = true; > + break; > + } > + } > + > + debug("%s: Exit, verified: %d\n", __func__, !found); > + return !found; > +} > + > +/** > + * efi_signature_verify_signers - verify signers' certificates with dbx > + * @msg: Signature > + * @dbx: Signature database > + * > + * Determine if any of signers' certificates in @msg may be verified > + * by any of certificates in signature database pointed to by @dbx. > + * This function is expected to be used against "dbx". > + * > + * Return: true if none of certificates is rejected, false otherwise. > + */ > +bool efi_signature_verify_signers(struct pkcs7_message *msg, > + struct efi_signature_store *dbx) > +{ > + struct pkcs7_signed_info *info; > + bool found = false; > + > + debug("%s: Enter, %p, %p\n", __func__, msg, dbx); > + > + if (!msg) > + goto out; > + > + for (info = msg->signed_infos; info; info = info->next) { > + if (info->signer && > + !efi_signature_verify_cert(info->signer, dbx)) { > + found = true; > + goto out; > + } > + } > +out: > + debug("%s: Exit, verified: %d\n", __func__, !found); > + return !found; > +} > + > +/** > + * efi_image_region_add - add an entry of region > + * @regs: Pointer to array of regions > + * @start: Start address of region > + * @end: End address of region > + * @nocheck: flag against overlapped regions > + * > + * Take one entry of region [@start, @end] and append it to the list > + * pointed to by @regs. If @nocheck is false, overlapping among entries > + * will be checked first. > + * > + * Return: 0 on success, status code (negative) on error > + */ > +efi_status_t efi_image_region_add(struct efi_image_regions *regs, > + const void *start, const void *end, > + int nocheck) > +{ > + struct image_region *reg; > + int i, j; > + > + if (regs->num >= regs->max) { > + debug("%s: no more room for regions\n", __func__); > + return EFI_OUT_OF_RESOURCES; > + } > + > + if (end < start) > + return EFI_INVALID_PARAMETER; > + > + for (i = 0; i < regs->num; i++) { > + reg = ®s->reg[i]; > + if (nocheck) > + continue; > + > + if (start > reg->data + reg->size) > + continue; > + > + if ((start >= reg->data && start < reg->data + reg->size) || > + (end > reg->data && end < reg->data + reg->size)) { > + debug("%s: new region already part of another\n", > + __func__); > + return EFI_INVALID_PARAMETER; > + } > + > + if (start < reg->data && end < reg->data + reg->size) { > + for (j = regs->num - 1; j >= i; j--) > + memcpy(®s->reg[j], ®s->reg[j + 1], > + sizeof(*reg)); > + break; > + } > + } > + > + reg = ®s->reg[i]; > + reg->data = start; > + reg->size = end - start; > + regs->num++; > + > + return EFI_SUCCESS; > +} > +#endif /* CONFIG_EFI_SECURE_BOOT */ >
On 2020-04-14 04:51, AKASHI Takahiro wrote: > In this commit, implemented are a couple of helper functions which will be > used to materialize variable authentication as well as image authentication > in later patches. > > Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org> > --- > include/efi_api.h | 87 +++++ > include/efi_loader.h | 72 ++++ > lib/efi_loader/Makefile | 1 + > lib/efi_loader/efi_signature.c | 583 +++++++++++++++++++++++++++++++++ > 4 files changed, 743 insertions(+) > create mode 100644 lib/efi_loader/efi_signature.c > > diff --git a/include/efi_api.h b/include/efi_api.h > index 1c40ffc4f56c..77d6bf2660b9 100644 > --- a/include/efi_api.h > +++ b/include/efi_api.h > @@ -18,6 +18,7 @@ > > #include <efi.h> > #include <charset.h> > +#include <pe.h> > > #ifdef CONFIG_EFI_LOADER > #include <asm/setjmp.h> > @@ -329,6 +330,10 @@ struct efi_runtime_services { > EFI_GUID(0x8be4df61, 0x93ca, 0x11d2, 0xaa, 0x0d, \ > 0x00, 0xe0, 0x98, 0x03, 0x2b, 0x8c) > > +#define EFI_IMAGE_SECURITY_DATABASE_GUID \ > + EFI_GUID(0xd719b2cb, 0x3d3a, 0x4596, 0xa3, 0xbc, \ > + 0xda, 0xd0, 0x0e, 0x67, 0x65, 0x6f) > + > #define EFI_FDT_GUID \ > EFI_GUID(0xb1b621d5, 0xf19c, 0x41a5, \ > 0x83, 0x0b, 0xd9, 0x15, 0x2c, 0x69, 0xaa, 0xe0) > @@ -1682,4 +1687,86 @@ struct efi_load_file_protocol { > #define LAST_ATTEMPT_STATUS_ERROR_UNSUCCESSFUL_VENDOR_RANGE_MIN 0x00001000 > #define LAST_ATTEMPT_STATUS_ERROR_UNSUCCESSFUL_VENDOR_RANGE_MAX 0x00004000 > > +/* Certificate types in signature database */ > +#define EFI_CERT_SHA256_GUID \ > + EFI_GUID(0xc1c41626, 0x504c, 0x4092, 0xac, 0xa9, \ > + 0x41, 0xf9, 0x36, 0x93, 0x43, 0x28) > +#define EFI_CERT_RSA2048_GUID \ > + EFI_GUID(0x3c5766e8, 0x269c, 0x4e34, 0xaa, 0x14, \ > + 0xed, 0x77, 0x6e, 0x85, 0xb3, 0xb6) > +#define EFI_CERT_X509_GUID \ > + EFI_GUID(0xa5c059a1, 0x94e4, 0x4aa7, 0x87, 0xb5, \ > + 0xab, 0x15, 0x5c, 0x2b, 0xf0, 0x72) > +#define EFI_CERT_X509_SHA256_GUID \ > + EFI_GUID(0x3bd2a492, 0x96c0, 0x4079, 0xb4, 0x20, \ > + 0xfc, 0xf9, 0x8e, 0xf1, 0x03, 0xed) > +#define EFI_CERT_TYPE_PKCS7_GUID \ > + EFI_GUID(0x4aafd29d, 0x68df, 0x49ee, 0x8a, 0xa9, \ > + 0x34, 0x7d, 0x37, 0x56, 0x65, 0xa7) > + > +/** > + * win_certificate_uefi_guid - A certificate that encapsulates > + * a GUID-specific signature > + * > + * @hdr: Windows certificate header > + * @cert_type: Certificate type > + * @cert_data: Certificate data > + */ > +struct win_certificate_uefi_guid { > + WIN_CERTIFICATE hdr; > + efi_guid_t cert_type; > + u8 cert_data[]; > +} __attribute__((__packed__)); > + > +/** > + * efi_variable_authentication_2 - A time-based authentication method > + * descriptor > + * > + * This structure describes an authentication information for > + * a variable with EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS > + * and should be included as part of a variable's value. > + * Only EFI_CERT_TYPE_PKCS7_GUID is accepted. > + * > + * @time_stamp: Descriptor's time stamp > + * @auth_info: Authentication info > + */ > +struct efi_variable_authentication_2 { > + struct efi_time time_stamp; > + struct win_certificate_uefi_guid auth_info; > +} __attribute__((__packed__)); > + > +/** > + * efi_signature_data - A format of signature > + * > + * This structure describes a single signature in signature database. > + * > + * @signature_owner: Signature owner > + * @signature_data: Signature data > + */ > +struct efi_signature_data { > + efi_guid_t signature_owner; > + u8 signature_data[]; > +} __attribute__((__packed__)); > + > +/** > + * efi_signature_list - A format of signature database > + * > + * This structure describes a list of signatures with the same type. > + * An authenticated variable's value is a concatenation of one or more > + * efi_signature_list's. > + * > + * @signature_type: Signature type > + * @signature_list_size: Size of signature list > + * @signature_header_size: Size of signature header > + * @signature_size: Size of signature > + */ > +struct efi_signature_list { > + efi_guid_t signature_type; > + u32 signature_list_size; > + u32 signature_header_size; > + u32 signature_size; > +/* u8 signature_header[signature_header_size]; */ > +/* struct efi_signature_data signatures[...][signature_size]; */ > +} __attribute__((__packed__)); > + > #endif > diff --git a/include/efi_loader.h b/include/efi_loader.h > index 3f2792892f34..8cf85d2fb7e2 100644 > --- a/include/efi_loader.h > +++ b/include/efi_loader.h > @@ -26,6 +26,7 @@ static inline void *guidcpy(void *dst, const void *src) > #if CONFIG_IS_ENABLED(EFI_LOADER) > > #include <linux/list.h> > +#include <linux/oid_registry.h> > > /* Maximum number of configuration tables */ > #define EFI_MAX_CONFIGURATION_TABLES 16 > @@ -178,6 +179,11 @@ extern const efi_guid_t efi_guid_hii_config_routing_protocol; > extern const efi_guid_t efi_guid_hii_config_access_protocol; > extern const efi_guid_t efi_guid_hii_database_protocol; > extern const efi_guid_t efi_guid_hii_string_protocol; > +/* GUIDs for authentication */ > +extern const efi_guid_t efi_guid_image_security_database; > +extern const efi_guid_t efi_guid_sha256; > +extern const efi_guid_t efi_guid_cert_x509; > +extern const efi_guid_t efi_guid_cert_x509_sha256; > > /* GUID of RNG protocol */ > extern const efi_guid_t efi_guid_rng_protocol; > @@ -680,6 +686,72 @@ void efi_deserialize_load_option(struct efi_load_option *lo, u8 *data); > unsigned long efi_serialize_load_option(struct efi_load_option *lo, u8 **data); > efi_status_t efi_bootmgr_load(efi_handle_t *handle); > > +#ifdef CONFIG_EFI_SECURE_BOOT Why do we need an #ifdef here? > +#include <image.h> > + > +/** > + * efi_image_regions - A list of memory regions > + * > + * @max: Maximum number of regions > + * @num: Number of regions > + * @reg: array of regions > + */ > +struct efi_image_regions { > + int max; > + int num; > + struct image_region reg[]; > +}; > + > +/** > + * efi_sig_data - A decoded data of struct efi_signature_data > + * > + * This structure represents an internal form of signature in > + * signature database. A listed list may represent a signature list. > + * > + * @next: Pointer to next entry > + * @onwer: Signature owner > + * @data: Pointer to signature data > + * @size: Size of signature data > + */ > +struct efi_sig_data { > + struct efi_sig_data *next; > + efi_guid_t owner; > + void *data; > + size_t size; > +}; > + > +/** > + * efi_signature_store - A decoded data of signature database > + * > + * This structure represents an internal form of signature database. > + * > + * @next: Pointer to next entry > + * @sig_type: Signature type > + * @sig_data_list: Pointer to signature list > + */ > +struct efi_signature_store { > + struct efi_signature_store *next; > + efi_guid_t sig_type; > + struct efi_sig_data *sig_data_list; > +}; > + > +struct x509_certificate; > +struct pkcs7_message; > + > +bool efi_signature_verify_cert(struct x509_certificate *cert, > + struct efi_signature_store *dbx); > +bool efi_signature_verify_signers(struct pkcs7_message *msg, > + struct efi_signature_store *dbx); > +bool efi_signature_verify_with_sigdb(struct efi_image_regions *regs, > + struct pkcs7_message *msg, > + struct efi_signature_store *db, > + struct x509_certificate **cert); > + > +efi_status_t efi_image_region_add(struct efi_image_regions *regs, > + const void *start, const void *end, > + int nocheck); > +#endif /* CONFIG_EFI_SECURE_BOOT */ > + > #else /* CONFIG_IS_ENABLED(EFI_LOADER) */ > > /* Without CONFIG_EFI_LOADER we don't have a runtime section, stub it out */ > diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile > index 9b3b70447336..eff3c25ec301 100644 > --- a/lib/efi_loader/Makefile > +++ b/lib/efi_loader/Makefile > @@ -44,3 +44,4 @@ obj-$(CONFIG_GENERATE_ACPI_TABLE) += efi_acpi.o > obj-$(CONFIG_GENERATE_SMBIOS_TABLE) += efi_smbios.o > obj-$(CONFIG_EFI_RNG_PROTOCOL) += efi_rng.o > obj-$(CONFIG_EFI_LOAD_FILE2_INITRD) += efi_load_initrd.o > +obj-y += efi_signature.o > diff --git a/lib/efi_loader/efi_signature.c b/lib/efi_loader/efi_signature.c > new file mode 100644 > index 000000000000..23dac94c0593 > --- /dev/null > +++ b/lib/efi_loader/efi_signature.c > @@ -0,0 +1,583 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +/* > + * Copyright (c) 2018 Patrick Wildt <patrick at blueri.se> > + * Copyright (c) 2019 Linaro Limited, Author: AKASHI Takahiro > + */ > + > +#include <common.h> > +#include <charset.h> > +#include <efi_loader.h> > +#include <image.h> > +#include <hexdump.h> > +#include <malloc.h> > +#include <pe.h> > +#include <linux/compat.h> > +#include <linux/oid_registry.h> > +#include <u-boot/rsa.h> > +#include <u-boot/sha256.h> > +/* > + * avoid duplicated inclusion: > + * #include "../lib/crypto/x509_parser.h" > + */ > +#include "../lib/crypto/pkcs7_parser.h" > + > +const efi_guid_t efi_guid_image_security_database = > + EFI_IMAGE_SECURITY_DATABASE_GUID; > +const efi_guid_t efi_guid_sha256 = EFI_CERT_SHA256_GUID; > +const efi_guid_t efi_guid_cert_rsa2048 = EFI_CERT_RSA2048_GUID; > +const efi_guid_t efi_guid_cert_x509 = EFI_CERT_X509_GUID; > +const efi_guid_t efi_guid_cert_x509_sha256 = EFI_CERT_X509_SHA256_GUID; > + > +#ifdef CONFIG_EFI_SECURE_BOOT > + > +/** > + * efi_hash_regions - calculate a hash value > + * @regs: List of regions > + * @hash: Pointer to a pointer to buffer holding a hash value > + * @size: Size of buffer to be returned > + * > + * Calculate a sha256 value of @regs and return a value in @hash. > + * > + * Return: true on success, false on error > + */ > +static bool efi_hash_regions(struct efi_image_regions *regs, void **hash, > + size_t *size) > +{ > + *size = 0; > + *hash = calloc(1, SHA256_SUM_LEN); > + if (!*hash) { > + debug("Out of memory\n"); > + return false; > + } > + *size = SHA256_SUM_LEN; > + > + hash_calculate("sha256", regs->reg, regs->num, *hash); > +#ifdef DEBUG > + debug("hash calculated:\n"); > + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1, > + *hash, SHA256_SUM_LEN, false); > +#endif > + > + return true; > +} > + > +/** > + * efi_hash_msg_content - calculate a hash value of contentInfo > + * @msg: Signature > + * @hash: Pointer to a pointer to buffer holding a hash value > + * @size: Size of buffer to be returned > + * > + * Calculate a sha256 value of contentInfo in @msg and return a value in @hash. > + * > + * Return: true on success, false on error > + */ > +static bool efi_hash_msg_content(struct pkcs7_message *msg, void **hash, > + size_t *size) > +{ > + struct image_region regtmp; > + > + *size = 0; > + *hash = calloc(1, SHA256_SUM_LEN); > + if (!*hash) { > + debug("Out of memory\n"); > + free(msg); > + return false; > + } > + *size = SHA256_SUM_LEN; > + > + regtmp.data = msg->data; > + regtmp.size = msg->data_len; > + > + hash_calculate("sha256", ®tmp, 1, *hash); > +#ifdef DEBUG > + debug("hash calculated based on contentInfo:\n"); > + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1, > + *hash, SHA256_SUM_LEN, false); > +#endif > + > + return true; > +} > + > +/** > + * efi_signature_verify - verify a signature with a certificate > + * @regs: List of regions to be authenticated > + * @signed_info: Pointer to PKCS7's signed_info > + * @cert: x509 certificate > + * > + * Signature pointed to by @signed_info against image pointed to by @regs > + * is verified by a certificate pointed to by @cert. > + * @signed_info holds a signature, including a message digest which is to be > + * compared with a hash value calculated from @regs. > + * > + * Return: true if signature is verified, false if not > + */ > +static bool efi_signature_verify(struct efi_image_regions *regs, > + struct pkcs7_message *msg, > + struct pkcs7_signed_info *ps_info, > + struct x509_certificate *cert) > +{ > + struct image_sign_info info; > + struct image_region regtmp[2]; > + void *hash; > + size_t size; > + char c; > + bool verified; > + > + debug("%s: Enter, %p, %p, %p(issuer: %s, subject: %s)\n", __func__, > + regs, ps_info, cert, cert->issuer, cert->subject); > + > + verified = false; > + > + memset(&info, '\0', sizeof(info)); > + info.padding = image_get_padding_algo("pkcs-1.5"); > + /* > + * Note: image_get_[checksum|crypto]_algo takes an string > + * argument like "<checksum>,<crypto>" > + * TODO: support other hash algorithms > + */ > + if (!strcmp(ps_info->sig->hash_algo, "sha1")) { > + info.checksum = image_get_checksum_algo("sha1,rsa2048"); > + info.name = "sha1,rsa2048"; > + } else if (!strcmp(ps_info->sig->hash_algo, "sha256")) { > + info.checksum = image_get_checksum_algo("sha256,rsa2048"); > + info.name = "sha256,rsa2048"; > + } else { > + debug("unknown msg digest algo: %s\n", ps_info->sig->hash_algo); > + goto out; > + } > + info.crypto = image_get_crypto_algo(info.name); > + > + info.key = cert->pub->key; > + info.keylen = cert->pub->keylen; > + > + /* verify signature */ > + debug("%s: crypto: %s, signature len:%x\n", __func__, > + info.name, ps_info->sig->s_size); > + if (ps_info->aa_set & (1UL << sinfo_has_message_digest)) { > + debug("%s: RSA verify authentication attribute\n", __func__); > + /* > + * NOTE: This path will be executed only for > + * PE image authentication > + */ > + > + /* check if hash matches digest first */ > + debug("checking msg digest first, len:0x%x\n", > + ps_info->msgdigest_len); > + > +#ifdef DEBUG > + debug("hash in database:\n"); > + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1, > + ps_info->msgdigest, ps_info->msgdigest_len, > + false); > +#endif > + /* against contentInfo first */ > + if ((msg->data && efi_hash_msg_content(msg, &hash, &size)) || > + /* for signed image */ > + efi_hash_regions(regs, &hash, &size)) { > + /* for authenticated variable */ > + if (ps_info->msgdigest_len != size || > + memcmp(hash, ps_info->msgdigest, size)) { > + debug("Digest doesn't match\n"); > + free(hash); > + goto out; > + } > + > + free(hash); > + } else { > + debug("Digesting image failed\n"); > + goto out; > + } > + > + /* against digest */ > + c = 0x31; > + regtmp[0].data = &c; > + regtmp[0].size = 1; > + regtmp[1].data = ps_info->authattrs; > + regtmp[1].size = ps_info->authattrs_len; > + > + if (!rsa_verify(&info, regtmp, 2, > + ps_info->sig->s, ps_info->sig->s_size)) > + verified = true; > + } else { > + debug("%s: RSA verify content data\n", __func__); > + /* against all data */ > + if (!rsa_verify(&info, regs->reg, regs->num, > + ps_info->sig->s, ps_info->sig->s_size)) > + verified = true; > + } > + > +out: > + debug("%s: Exit, verified: %d\n", __func__, verified); > + return verified; > +} > + > +/** > + * efi_signature_verify_with_list - verify a signature with signature list > + * @regs: List of regions to be authenticated > + * @msg: Signature > + * @signed_info: Pointer to PKCS7's signed_info > + * @siglist: Signature list for certificates > + * @valid_cert: x509 certificate that verifies this signature > + * > + * Signature pointed to by @signed_info against image pointed to by @regs > + * is verified by signature list pointed to by @siglist. > + * Signature database is a simple concatenation of one or more > + * signature list(s). > + * > + * Return: true if signature is verified, false if not > + */ > +static > +bool efi_signature_verify_with_list(struct efi_image_regions *regs, > + struct pkcs7_message *msg, > + struct pkcs7_signed_info *signed_info, > + struct efi_signature_store *siglist, > + struct x509_certificate **valid_cert) > +{ > + struct x509_certificate *cert; > + struct efi_sig_data *sig_data; > + bool verified = false; > + > + debug("%s: Enter, %p, %p, %p, %p\n", __func__, > + regs, signed_info, siglist, valid_cert); > + > + if (!signed_info) { > + void *hash; > + size_t size; > + > + debug("%s: unsigned image\n", __func__); > + /* > + * verify based on calculated hash value > + * TODO: support other hash algorithms > + */ > + if (guidcmp(&siglist->sig_type, &efi_guid_sha256)) { > + debug("Digest algorithm is not supported: %pUl\n", > + &siglist->sig_type); > + goto out; > + } > + > + if (!efi_hash_regions(regs, &hash, &size)) { > + debug("Digesting unsigned image failed\n"); > + goto out; > + } > + > + /* go through the list */ > + for (sig_data = siglist->sig_data_list; sig_data; > + sig_data = sig_data->next) { > +#ifdef DEBUG > + debug("Msg digest in database:\n"); > + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1, > + sig_data->data, sig_data->size, false); > +#endif > + if ((sig_data->size == size) && > + !memcmp(sig_data->data, hash, size)) { > + verified = true; > + free(hash); > + goto out; > + } > + } > + free(hash); > + goto out; > + } > + > + debug("%s: signed image\n", __func__); > + if (guidcmp(&siglist->sig_type, &efi_guid_cert_x509)) { > + debug("Signature type is not supported: %pUl\n", > + &siglist->sig_type); > + goto out; > + } > + > + /* go through the list */ > + for (sig_data = siglist->sig_data_list; sig_data; > + sig_data = sig_data->next) { > + /* TODO: support owner check based on policy */ > + > + cert = x509_cert_parse(sig_data->data, sig_data->size); > + if (IS_ERR(cert)) { > + debug("Parsing x509 certificate failed\n"); > + goto out; > + } > + > + verified = efi_signature_verify(regs, msg, signed_info, cert); > + > + if (verified) { > + if (valid_cert) > + *valid_cert = cert; > + else > + x509_free_certificate(cert); > + break; > + } > + x509_free_certificate(cert); > + } > + > +out: > + debug("%s: Exit, verified: %d\n", __func__, verified); > + return verified; > +} > + > +/** > + * efi_signature_verify_with_sigdb - verify a signature with db > + * @regs: List of regions to be authenticated > + * @msg: Signature > + * @db: Signature database for trusted certificates > + * @cert: x509 certificate that verifies this signature > + * > + * Signature pointed to by @msg against image pointed to by @regs > + * is verified by signature database pointed to by @db. > + * > + * Return: true if signature is verified, false if not > + */ > +bool efi_signature_verify_with_sigdb(struct efi_image_regions *regs, > + struct pkcs7_message *msg, > + struct efi_signature_store *db, > + struct x509_certificate **cert) > +{ > + struct pkcs7_signed_info *info; > + struct efi_signature_store *siglist; > + bool verified = false; > + > + debug("%s: Enter, %p, %p, %p, %p\n", __func__, regs, msg, db, cert); > + > + if (!db) > + goto out; > + > + if (!db->sig_data_list) > + goto out; > + > + /* for unsigned image */ > + if (!msg) { > + debug("%s: Verify unsigned image with db\n", __func__); > + for (siglist = db; siglist; siglist = siglist->next) > + if (efi_signature_verify_with_list(regs, NULL, NULL, > + siglist, cert)) { > + verified = true; > + goto out; > + } > + > + goto out; > + } > + > + /* for signed image or variable */ > + debug("%s: Verify signed image with db\n", __func__); > + for (info = msg->signed_infos; info; info = info->next) { > + debug("Signed Info: digest algo: %s, pkey algo: %s\n", > + info->sig->hash_algo, info->sig->pkey_algo); > + > + for (siglist = db; siglist; siglist = siglist->next) { > + if (efi_signature_verify_with_list(regs, msg, info, > + siglist, cert)) { > + verified = true; > + goto out; > + } > + } > + } > + > +out: > + debug("%s: Exit, verified: %d\n", __func__, verified); > + return verified; > +} > + > +/** > + * efi_search_siglist - search signature list for a certificate > + * @cert: x509 certificate > + * @siglist: Signature list > + * @revoc_time: Pointer to buffer for revocation time > + * > + * Search signature list pointed to by @siglist and find a certificate > + * pointed to by @cert. > + * If found, revocation time that is specified in signature database is > + * returned in @revoc_time. > + * > + * Return: true if certificate is found, false if not > + */ > +static bool efi_search_siglist(struct x509_certificate *cert, > + struct efi_signature_store *siglist, > + time64_t *revoc_time) > +{ > + struct image_region reg[1]; > + void *hash = NULL, *msg = NULL; > + struct efi_sig_data *sig_data; > + bool found = false; > + > + /* can be null */ > + if (!siglist->sig_data_list) > + return false; > + > + if (guidcmp(&siglist->sig_type, &efi_guid_cert_x509_sha256)) { > + /* TODO: other hash algos */ > + debug("Certificate's digest type is not supported: %pUl\n", > + &siglist->sig_type); > + goto out; > + } > + > + /* calculate hash of TBSCertificate */ > + msg = calloc(1, SHA256_SUM_LEN); > + if (!msg) { > + debug("Out of memory\n"); > + goto out; > + } > + > + hash = calloc(1, SHA256_SUM_LEN); > + if (!hash) { > + debug("Out of memory\n"); > + goto out; > + } > + > + reg[0].data = cert->tbs; > + reg[0].size = cert->tbs_size; > + hash_calculate("sha256", reg, 1, msg); > + > + /* go through signature list */ > + for (sig_data = siglist->sig_data_list; sig_data; > + sig_data = sig_data->next) { > + /* > + * struct efi_cert_x509_sha256 { > + * u8 tbs_hash[256/8]; > + * time64_t revocation_time; > + * }; > + */ > + if ((sig_data->size == SHA256_SUM_LEN) && > + !memcmp(sig_data->data, hash, SHA256_SUM_LEN)) { > + memcpy(revoc_time, sig_data->data + SHA256_SUM_LEN, > + sizeof(*revoc_time)); > + found = true; > + goto out; > + } > + } > + > +out: > + free(hash); > + free(msg); > + > + return found; > +} > + > +/** > + * efi_signature_verify_cert - verify a certificate with dbx > + * @cert: x509 certificate > + * @dbx: Signature database > + * > + * Search signature database pointed to by @dbx and find a certificate > + * pointed to by @cert. > + * This function is expected to be used against "dbx". > + * > + * Return: true if a certificate is not rejected, false otherwise. > + */ > +bool efi_signature_verify_cert(struct x509_certificate *cert, > + struct efi_signature_store *dbx) > +{ > + struct efi_signature_store *siglist; > + time64_t revoc_time; > + bool found = false; > + > + debug("%s: Enter, %p, %p\n", __func__, dbx, cert); > + > + if (!cert) > + return false; > + > + for (siglist = dbx; siglist; siglist = siglist->next) { > + if (efi_search_siglist(cert, siglist, &revoc_time)) { > + /* TODO */ > + /* compare signing time with revocation time */ > + > + found = true; > + break; > + } > + } > + > + debug("%s: Exit, verified: %d\n", __func__, !found); > + return !found; > +} > + > +/** > + * efi_signature_verify_signers - verify signers' certificates with dbx > + * @msg: Signature > + * @dbx: Signature database > + * > + * Determine if any of signers' certificates in @msg may be verified > + * by any of certificates in signature database pointed to by @dbx. > + * This function is expected to be used against "dbx". > + * > + * Return: true if none of certificates is rejected, false otherwise. > + */ > +bool efi_signature_verify_signers(struct pkcs7_message *msg, > + struct efi_signature_store *dbx) > +{ > + struct pkcs7_signed_info *info; > + bool found = false; > + > + debug("%s: Enter, %p, %p\n", __func__, msg, dbx); > + > + if (!msg) > + goto out; > + > + for (info = msg->signed_infos; info; info = info->next) { > + if (info->signer && > + !efi_signature_verify_cert(info->signer, dbx)) { > + found = true; > + goto out; > + } > + } > +out: > + debug("%s: Exit, verified: %d\n", __func__, !found); > + return !found; > +} > + > +/** > + * efi_image_region_add - add an entry of region > + * @regs: Pointer to array of regions > + * @start: Start address of region > + * @end: End address of region > + * @nocheck: flag against overlapped regions > + * > + * Take one entry of region [@start, @end] and append it to the list > + * pointed to by @regs. If @nocheck is false, overlapping among entries > + * will be checked first. > + * > + * Return: 0 on success, status code (negative) on error > + */ > +efi_status_t efi_image_region_add(struct efi_image_regions *regs, > + const void *start, const void *end, > + int nocheck) > +{ > + struct image_region *reg; > + int i, j; > + > + if (regs->num >= regs->max) { > + debug("%s: no more room for regions\n", __func__); > + return EFI_OUT_OF_RESOURCES; > + } > + > + if (end < start) > + return EFI_INVALID_PARAMETER; > + > + for (i = 0; i < regs->num; i++) { > + reg = ®s->reg[i]; > + if (nocheck) > + continue; > + > + if (start > reg->data + reg->size) > + continue; > + > + if ((start >= reg->data && start < reg->data + reg->size) || > + (end > reg->data && end < reg->data + reg->size)) { > + debug("%s: new region already part of another\n", > + __func__); > + return EFI_INVALID_PARAMETER; > + } > + > + if (start < reg->data && end < reg->data + reg->size) { > + for (j = regs->num - 1; j >= i; j--) > + memcpy(®s->reg[j], ®s->reg[j + 1], > + sizeof(*reg)); > + break; > + } > + } > + > + reg = ®s->reg[i]; > + reg->data = start; > + reg->size = end - start; > + regs->num++; > + > + return EFI_SUCCESS; > +} > +#endif /* CONFIG_EFI_SECURE_BOOT */ > If I define CONFIG_EFI_SECURE_BOOT I get a warning: lib/efi_loader/efi_signature.c: In function ?efi_hash_regions?: lib/efi_loader/efi_signature.c:52:2: warning: implicit declaration of function ?hash_calculate? [-Wimplicit-function-declaration] 52 | hash_calculate("sha256", regs->reg, regs->num, *hash); | ^~~~~~~~~~~~~~ #include u-boot/rsa-checksum.h seems to be missing in the code. Best regards Heinrich
On 2020-04-14 16:52, Heinrich Schuchardt wrote: > On 2020-04-14 04:51, AKASHI Takahiro wrote: >> In this commit, implemented are a couple of helper functions which will be >> used to materialize variable authentication as well as image authentication >> in later patches. >> >> Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org> >> --- >> include/efi_api.h | 87 +++++ >> include/efi_loader.h | 72 ++++ >> lib/efi_loader/Makefile | 1 + >> lib/efi_loader/efi_signature.c | 583 +++++++++++++++++++++++++++++++++ >> 4 files changed, 743 insertions(+) >> create mode 100644 lib/efi_loader/efi_signature.c >> >> diff --git a/include/efi_api.h b/include/efi_api.h >> index 1c40ffc4f56c..77d6bf2660b9 100644 >> --- a/include/efi_api.h >> +++ b/include/efi_api.h >> @@ -18,6 +18,7 @@ >> >> #include <efi.h> >> #include <charset.h> >> +#include <pe.h> >> >> #ifdef CONFIG_EFI_LOADER >> #include <asm/setjmp.h> >> @@ -329,6 +330,10 @@ struct efi_runtime_services { >> EFI_GUID(0x8be4df61, 0x93ca, 0x11d2, 0xaa, 0x0d, \ >> 0x00, 0xe0, 0x98, 0x03, 0x2b, 0x8c) >> >> +#define EFI_IMAGE_SECURITY_DATABASE_GUID \ >> + EFI_GUID(0xd719b2cb, 0x3d3a, 0x4596, 0xa3, 0xbc, \ >> + 0xda, 0xd0, 0x0e, 0x67, 0x65, 0x6f) >> + >> #define EFI_FDT_GUID \ >> EFI_GUID(0xb1b621d5, 0xf19c, 0x41a5, \ >> 0x83, 0x0b, 0xd9, 0x15, 0x2c, 0x69, 0xaa, 0xe0) >> @@ -1682,4 +1687,86 @@ struct efi_load_file_protocol { >> #define LAST_ATTEMPT_STATUS_ERROR_UNSUCCESSFUL_VENDOR_RANGE_MIN 0x00001000 >> #define LAST_ATTEMPT_STATUS_ERROR_UNSUCCESSFUL_VENDOR_RANGE_MAX 0x00004000 >> >> +/* Certificate types in signature database */ >> +#define EFI_CERT_SHA256_GUID \ >> + EFI_GUID(0xc1c41626, 0x504c, 0x4092, 0xac, 0xa9, \ >> + 0x41, 0xf9, 0x36, 0x93, 0x43, 0x28) >> +#define EFI_CERT_RSA2048_GUID \ >> + EFI_GUID(0x3c5766e8, 0x269c, 0x4e34, 0xaa, 0x14, \ >> + 0xed, 0x77, 0x6e, 0x85, 0xb3, 0xb6) >> +#define EFI_CERT_X509_GUID \ >> + EFI_GUID(0xa5c059a1, 0x94e4, 0x4aa7, 0x87, 0xb5, \ >> + 0xab, 0x15, 0x5c, 0x2b, 0xf0, 0x72) >> +#define EFI_CERT_X509_SHA256_GUID \ >> + EFI_GUID(0x3bd2a492, 0x96c0, 0x4079, 0xb4, 0x20, \ >> + 0xfc, 0xf9, 0x8e, 0xf1, 0x03, 0xed) >> +#define EFI_CERT_TYPE_PKCS7_GUID \ >> + EFI_GUID(0x4aafd29d, 0x68df, 0x49ee, 0x8a, 0xa9, \ >> + 0x34, 0x7d, 0x37, 0x56, 0x65, 0xa7) >> + >> +/** >> + * win_certificate_uefi_guid - A certificate that encapsulates >> + * a GUID-specific signature >> + * >> + * @hdr: Windows certificate header >> + * @cert_type: Certificate type >> + * @cert_data: Certificate data >> + */ >> +struct win_certificate_uefi_guid { >> + WIN_CERTIFICATE hdr; >> + efi_guid_t cert_type; >> + u8 cert_data[]; >> +} __attribute__((__packed__)); >> + >> +/** >> + * efi_variable_authentication_2 - A time-based authentication method >> + * descriptor >> + * >> + * This structure describes an authentication information for >> + * a variable with EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS >> + * and should be included as part of a variable's value. >> + * Only EFI_CERT_TYPE_PKCS7_GUID is accepted. >> + * >> + * @time_stamp: Descriptor's time stamp >> + * @auth_info: Authentication info >> + */ >> +struct efi_variable_authentication_2 { >> + struct efi_time time_stamp; >> + struct win_certificate_uefi_guid auth_info; >> +} __attribute__((__packed__)); >> + >> +/** >> + * efi_signature_data - A format of signature >> + * >> + * This structure describes a single signature in signature database. >> + * >> + * @signature_owner: Signature owner >> + * @signature_data: Signature data >> + */ >> +struct efi_signature_data { >> + efi_guid_t signature_owner; >> + u8 signature_data[]; >> +} __attribute__((__packed__)); >> + >> +/** >> + * efi_signature_list - A format of signature database >> + * >> + * This structure describes a list of signatures with the same type. >> + * An authenticated variable's value is a concatenation of one or more >> + * efi_signature_list's. >> + * >> + * @signature_type: Signature type >> + * @signature_list_size: Size of signature list >> + * @signature_header_size: Size of signature header >> + * @signature_size: Size of signature >> + */ >> +struct efi_signature_list { >> + efi_guid_t signature_type; >> + u32 signature_list_size; >> + u32 signature_header_size; >> + u32 signature_size; >> +/* u8 signature_header[signature_header_size]; */ >> +/* struct efi_signature_data signatures[...][signature_size]; */ >> +} __attribute__((__packed__)); >> + >> #endif >> diff --git a/include/efi_loader.h b/include/efi_loader.h >> index 3f2792892f34..8cf85d2fb7e2 100644 >> --- a/include/efi_loader.h >> +++ b/include/efi_loader.h >> @@ -26,6 +26,7 @@ static inline void *guidcpy(void *dst, const void *src) >> #if CONFIG_IS_ENABLED(EFI_LOADER) >> >> #include <linux/list.h> >> +#include <linux/oid_registry.h> >> >> /* Maximum number of configuration tables */ >> #define EFI_MAX_CONFIGURATION_TABLES 16 >> @@ -178,6 +179,11 @@ extern const efi_guid_t efi_guid_hii_config_routing_protocol; >> extern const efi_guid_t efi_guid_hii_config_access_protocol; >> extern const efi_guid_t efi_guid_hii_database_protocol; >> extern const efi_guid_t efi_guid_hii_string_protocol; >> +/* GUIDs for authentication */ >> +extern const efi_guid_t efi_guid_image_security_database; >> +extern const efi_guid_t efi_guid_sha256; >> +extern const efi_guid_t efi_guid_cert_x509; >> +extern const efi_guid_t efi_guid_cert_x509_sha256; >> >> /* GUID of RNG protocol */ >> extern const efi_guid_t efi_guid_rng_protocol; >> @@ -680,6 +686,72 @@ void efi_deserialize_load_option(struct efi_load_option *lo, u8 *data); >> unsigned long efi_serialize_load_option(struct efi_load_option *lo, u8 **data); >> efi_status_t efi_bootmgr_load(efi_handle_t *handle); >> >> +#ifdef CONFIG_EFI_SECURE_BOOT > > Why do we need an #ifdef here? > >> +#include <image.h> >> + >> +/** >> + * efi_image_regions - A list of memory regions >> + * >> + * @max: Maximum number of regions >> + * @num: Number of regions >> + * @reg: array of regions >> + */ >> +struct efi_image_regions { >> + int max; >> + int num; >> + struct image_region reg[]; >> +}; >> + >> +/** >> + * efi_sig_data - A decoded data of struct efi_signature_data >> + * >> + * This structure represents an internal form of signature in >> + * signature database. A listed list may represent a signature list. >> + * >> + * @next: Pointer to next entry >> + * @onwer: Signature owner >> + * @data: Pointer to signature data >> + * @size: Size of signature data >> + */ >> +struct efi_sig_data { >> + struct efi_sig_data *next; >> + efi_guid_t owner; >> + void *data; >> + size_t size; >> +}; >> + >> +/** >> + * efi_signature_store - A decoded data of signature database >> + * >> + * This structure represents an internal form of signature database. >> + * >> + * @next: Pointer to next entry >> + * @sig_type: Signature type >> + * @sig_data_list: Pointer to signature list >> + */ >> +struct efi_signature_store { >> + struct efi_signature_store *next; >> + efi_guid_t sig_type; >> + struct efi_sig_data *sig_data_list; >> +}; >> + >> +struct x509_certificate; >> +struct pkcs7_message; >> + >> +bool efi_signature_verify_cert(struct x509_certificate *cert, >> + struct efi_signature_store *dbx); >> +bool efi_signature_verify_signers(struct pkcs7_message *msg, >> + struct efi_signature_store *dbx); >> +bool efi_signature_verify_with_sigdb(struct efi_image_regions *regs, >> + struct pkcs7_message *msg, >> + struct efi_signature_store *db, >> + struct x509_certificate **cert); >> + >> +efi_status_t efi_image_region_add(struct efi_image_regions *regs, >> + const void *start, const void *end, >> + int nocheck); >> +#endif /* CONFIG_EFI_SECURE_BOOT */ >> + >> #else /* CONFIG_IS_ENABLED(EFI_LOADER) */ >> >> /* Without CONFIG_EFI_LOADER we don't have a runtime section, stub it out */ >> diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile >> index 9b3b70447336..eff3c25ec301 100644 >> --- a/lib/efi_loader/Makefile >> +++ b/lib/efi_loader/Makefile >> @@ -44,3 +44,4 @@ obj-$(CONFIG_GENERATE_ACPI_TABLE) += efi_acpi.o >> obj-$(CONFIG_GENERATE_SMBIOS_TABLE) += efi_smbios.o >> obj-$(CONFIG_EFI_RNG_PROTOCOL) += efi_rng.o >> obj-$(CONFIG_EFI_LOAD_FILE2_INITRD) += efi_load_initrd.o >> +obj-y += efi_signature.o >> diff --git a/lib/efi_loader/efi_signature.c b/lib/efi_loader/efi_signature.c >> new file mode 100644 >> index 000000000000..23dac94c0593 >> --- /dev/null >> +++ b/lib/efi_loader/efi_signature.c >> @@ -0,0 +1,583 @@ >> +// SPDX-License-Identifier: GPL-2.0+ >> +/* >> + * Copyright (c) 2018 Patrick Wildt <patrick at blueri.se> >> + * Copyright (c) 2019 Linaro Limited, Author: AKASHI Takahiro >> + */ >> + >> +#include <common.h> >> +#include <charset.h> >> +#include <efi_loader.h> >> +#include <image.h> >> +#include <hexdump.h> >> +#include <malloc.h> >> +#include <pe.h> >> +#include <linux/compat.h> >> +#include <linux/oid_registry.h> >> +#include <u-boot/rsa.h> >> +#include <u-boot/sha256.h> >> +/* >> + * avoid duplicated inclusion: >> + * #include "../lib/crypto/x509_parser.h" >> + */ >> +#include "../lib/crypto/pkcs7_parser.h" >> + >> +const efi_guid_t efi_guid_image_security_database = >> + EFI_IMAGE_SECURITY_DATABASE_GUID; >> +const efi_guid_t efi_guid_sha256 = EFI_CERT_SHA256_GUID; >> +const efi_guid_t efi_guid_cert_rsa2048 = EFI_CERT_RSA2048_GUID; >> +const efi_guid_t efi_guid_cert_x509 = EFI_CERT_X509_GUID; >> +const efi_guid_t efi_guid_cert_x509_sha256 = EFI_CERT_X509_SHA256_GUID; >> + >> +#ifdef CONFIG_EFI_SECURE_BOOT >> + >> +/** >> + * efi_hash_regions - calculate a hash value >> + * @regs: List of regions >> + * @hash: Pointer to a pointer to buffer holding a hash value >> + * @size: Size of buffer to be returned >> + * >> + * Calculate a sha256 value of @regs and return a value in @hash. >> + * >> + * Return: true on success, false on error >> + */ >> +static bool efi_hash_regions(struct efi_image_regions *regs, void **hash, >> + size_t *size) >> +{ >> + *size = 0; >> + *hash = calloc(1, SHA256_SUM_LEN); >> + if (!*hash) { >> + debug("Out of memory\n"); >> + return false; >> + } >> + *size = SHA256_SUM_LEN; >> + >> + hash_calculate("sha256", regs->reg, regs->num, *hash); >> +#ifdef DEBUG >> + debug("hash calculated:\n"); >> + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1, >> + *hash, SHA256_SUM_LEN, false); >> +#endif >> + >> + return true; >> +} >> + >> +/** >> + * efi_hash_msg_content - calculate a hash value of contentInfo >> + * @msg: Signature >> + * @hash: Pointer to a pointer to buffer holding a hash value >> + * @size: Size of buffer to be returned >> + * >> + * Calculate a sha256 value of contentInfo in @msg and return a value in @hash. >> + * >> + * Return: true on success, false on error >> + */ >> +static bool efi_hash_msg_content(struct pkcs7_message *msg, void **hash, >> + size_t *size) >> +{ >> + struct image_region regtmp; >> + >> + *size = 0; >> + *hash = calloc(1, SHA256_SUM_LEN); >> + if (!*hash) { >> + debug("Out of memory\n"); >> + free(msg); >> + return false; >> + } >> + *size = SHA256_SUM_LEN; >> + >> + regtmp.data = msg->data; >> + regtmp.size = msg->data_len; >> + >> + hash_calculate("sha256", ®tmp, 1, *hash); >> +#ifdef DEBUG >> + debug("hash calculated based on contentInfo:\n"); >> + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1, >> + *hash, SHA256_SUM_LEN, false); >> +#endif >> + >> + return true; >> +} >> + >> +/** >> + * efi_signature_verify - verify a signature with a certificate >> + * @regs: List of regions to be authenticated >> + * @signed_info: Pointer to PKCS7's signed_info >> + * @cert: x509 certificate >> + * >> + * Signature pointed to by @signed_info against image pointed to by @regs >> + * is verified by a certificate pointed to by @cert. >> + * @signed_info holds a signature, including a message digest which is to be >> + * compared with a hash value calculated from @regs. >> + * >> + * Return: true if signature is verified, false if not >> + */ >> +static bool efi_signature_verify(struct efi_image_regions *regs, >> + struct pkcs7_message *msg, >> + struct pkcs7_signed_info *ps_info, >> + struct x509_certificate *cert) >> +{ >> + struct image_sign_info info; >> + struct image_region regtmp[2]; >> + void *hash; >> + size_t size; >> + char c; >> + bool verified; >> + >> + debug("%s: Enter, %p, %p, %p(issuer: %s, subject: %s)\n", __func__, >> + regs, ps_info, cert, cert->issuer, cert->subject); >> + >> + verified = false; >> + >> + memset(&info, '\0', sizeof(info)); >> + info.padding = image_get_padding_algo("pkcs-1.5"); >> + /* >> + * Note: image_get_[checksum|crypto]_algo takes an string >> + * argument like "<checksum>,<crypto>" >> + * TODO: support other hash algorithms >> + */ >> + if (!strcmp(ps_info->sig->hash_algo, "sha1")) { >> + info.checksum = image_get_checksum_algo("sha1,rsa2048"); >> + info.name = "sha1,rsa2048"; >> + } else if (!strcmp(ps_info->sig->hash_algo, "sha256")) { >> + info.checksum = image_get_checksum_algo("sha256,rsa2048"); >> + info.name = "sha256,rsa2048"; >> + } else { >> + debug("unknown msg digest algo: %s\n", ps_info->sig->hash_algo); >> + goto out; >> + } >> + info.crypto = image_get_crypto_algo(info.name); >> + >> + info.key = cert->pub->key; >> + info.keylen = cert->pub->keylen; >> + >> + /* verify signature */ >> + debug("%s: crypto: %s, signature len:%x\n", __func__, >> + info.name, ps_info->sig->s_size); >> + if (ps_info->aa_set & (1UL << sinfo_has_message_digest)) { >> + debug("%s: RSA verify authentication attribute\n", __func__); >> + /* >> + * NOTE: This path will be executed only for >> + * PE image authentication >> + */ >> + >> + /* check if hash matches digest first */ >> + debug("checking msg digest first, len:0x%x\n", >> + ps_info->msgdigest_len); >> + >> +#ifdef DEBUG >> + debug("hash in database:\n"); >> + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1, >> + ps_info->msgdigest, ps_info->msgdigest_len, >> + false); >> +#endif >> + /* against contentInfo first */ >> + if ((msg->data && efi_hash_msg_content(msg, &hash, &size)) || >> + /* for signed image */ >> + efi_hash_regions(regs, &hash, &size)) { >> + /* for authenticated variable */ >> + if (ps_info->msgdigest_len != size || >> + memcmp(hash, ps_info->msgdigest, size)) { >> + debug("Digest doesn't match\n"); >> + free(hash); >> + goto out; >> + } >> + >> + free(hash); >> + } else { >> + debug("Digesting image failed\n"); >> + goto out; >> + } >> + >> + /* against digest */ >> + c = 0x31; >> + regtmp[0].data = &c; >> + regtmp[0].size = 1; >> + regtmp[1].data = ps_info->authattrs; >> + regtmp[1].size = ps_info->authattrs_len; >> + >> + if (!rsa_verify(&info, regtmp, 2, >> + ps_info->sig->s, ps_info->sig->s_size)) >> + verified = true; >> + } else { >> + debug("%s: RSA verify content data\n", __func__); >> + /* against all data */ >> + if (!rsa_verify(&info, regs->reg, regs->num, >> + ps_info->sig->s, ps_info->sig->s_size)) >> + verified = true; >> + } >> + >> +out: >> + debug("%s: Exit, verified: %d\n", __func__, verified); >> + return verified; >> +} >> + >> +/** >> + * efi_signature_verify_with_list - verify a signature with signature list >> + * @regs: List of regions to be authenticated >> + * @msg: Signature >> + * @signed_info: Pointer to PKCS7's signed_info >> + * @siglist: Signature list for certificates >> + * @valid_cert: x509 certificate that verifies this signature >> + * >> + * Signature pointed to by @signed_info against image pointed to by @regs >> + * is verified by signature list pointed to by @siglist. >> + * Signature database is a simple concatenation of one or more >> + * signature list(s). >> + * >> + * Return: true if signature is verified, false if not >> + */ >> +static >> +bool efi_signature_verify_with_list(struct efi_image_regions *regs, >> + struct pkcs7_message *msg, >> + struct pkcs7_signed_info *signed_info, >> + struct efi_signature_store *siglist, >> + struct x509_certificate **valid_cert) >> +{ >> + struct x509_certificate *cert; >> + struct efi_sig_data *sig_data; >> + bool verified = false; >> + >> + debug("%s: Enter, %p, %p, %p, %p\n", __func__, >> + regs, signed_info, siglist, valid_cert); >> + >> + if (!signed_info) { >> + void *hash; >> + size_t size; >> + >> + debug("%s: unsigned image\n", __func__); >> + /* >> + * verify based on calculated hash value >> + * TODO: support other hash algorithms >> + */ >> + if (guidcmp(&siglist->sig_type, &efi_guid_sha256)) { >> + debug("Digest algorithm is not supported: %pUl\n", >> + &siglist->sig_type); >> + goto out; >> + } >> + >> + if (!efi_hash_regions(regs, &hash, &size)) { >> + debug("Digesting unsigned image failed\n"); >> + goto out; >> + } >> + >> + /* go through the list */ >> + for (sig_data = siglist->sig_data_list; sig_data; >> + sig_data = sig_data->next) { >> +#ifdef DEBUG >> + debug("Msg digest in database:\n"); >> + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1, >> + sig_data->data, sig_data->size, false); >> +#endif >> + if ((sig_data->size == size) && >> + !memcmp(sig_data->data, hash, size)) { >> + verified = true; >> + free(hash); >> + goto out; >> + } >> + } >> + free(hash); >> + goto out; >> + } >> + >> + debug("%s: signed image\n", __func__); >> + if (guidcmp(&siglist->sig_type, &efi_guid_cert_x509)) { >> + debug("Signature type is not supported: %pUl\n", >> + &siglist->sig_type); >> + goto out; >> + } >> + >> + /* go through the list */ >> + for (sig_data = siglist->sig_data_list; sig_data; >> + sig_data = sig_data->next) { >> + /* TODO: support owner check based on policy */ >> + >> + cert = x509_cert_parse(sig_data->data, sig_data->size); >> + if (IS_ERR(cert)) { >> + debug("Parsing x509 certificate failed\n"); >> + goto out; >> + } >> + >> + verified = efi_signature_verify(regs, msg, signed_info, cert); >> + >> + if (verified) { >> + if (valid_cert) >> + *valid_cert = cert; >> + else >> + x509_free_certificate(cert); >> + break; >> + } >> + x509_free_certificate(cert); >> + } >> + >> +out: >> + debug("%s: Exit, verified: %d\n", __func__, verified); >> + return verified; >> +} >> + >> +/** >> + * efi_signature_verify_with_sigdb - verify a signature with db >> + * @regs: List of regions to be authenticated >> + * @msg: Signature >> + * @db: Signature database for trusted certificates >> + * @cert: x509 certificate that verifies this signature >> + * >> + * Signature pointed to by @msg against image pointed to by @regs >> + * is verified by signature database pointed to by @db. >> + * >> + * Return: true if signature is verified, false if not >> + */ >> +bool efi_signature_verify_with_sigdb(struct efi_image_regions *regs, >> + struct pkcs7_message *msg, >> + struct efi_signature_store *db, >> + struct x509_certificate **cert) >> +{ >> + struct pkcs7_signed_info *info; >> + struct efi_signature_store *siglist; >> + bool verified = false; >> + >> + debug("%s: Enter, %p, %p, %p, %p\n", __func__, regs, msg, db, cert); >> + >> + if (!db) >> + goto out; >> + >> + if (!db->sig_data_list) >> + goto out; >> + >> + /* for unsigned image */ >> + if (!msg) { >> + debug("%s: Verify unsigned image with db\n", __func__); >> + for (siglist = db; siglist; siglist = siglist->next) >> + if (efi_signature_verify_with_list(regs, NULL, NULL, >> + siglist, cert)) { >> + verified = true; >> + goto out; >> + } >> + >> + goto out; >> + } >> + >> + /* for signed image or variable */ >> + debug("%s: Verify signed image with db\n", __func__); >> + for (info = msg->signed_infos; info; info = info->next) { >> + debug("Signed Info: digest algo: %s, pkey algo: %s\n", >> + info->sig->hash_algo, info->sig->pkey_algo); >> + >> + for (siglist = db; siglist; siglist = siglist->next) { >> + if (efi_signature_verify_with_list(regs, msg, info, >> + siglist, cert)) { >> + verified = true; >> + goto out; >> + } >> + } >> + } >> + >> +out: >> + debug("%s: Exit, verified: %d\n", __func__, verified); >> + return verified; >> +} >> + >> +/** >> + * efi_search_siglist - search signature list for a certificate >> + * @cert: x509 certificate >> + * @siglist: Signature list >> + * @revoc_time: Pointer to buffer for revocation time >> + * >> + * Search signature list pointed to by @siglist and find a certificate >> + * pointed to by @cert. >> + * If found, revocation time that is specified in signature database is >> + * returned in @revoc_time. >> + * >> + * Return: true if certificate is found, false if not >> + */ >> +static bool efi_search_siglist(struct x509_certificate *cert, >> + struct efi_signature_store *siglist, >> + time64_t *revoc_time) >> +{ >> + struct image_region reg[1]; >> + void *hash = NULL, *msg = NULL; >> + struct efi_sig_data *sig_data; >> + bool found = false; >> + >> + /* can be null */ >> + if (!siglist->sig_data_list) >> + return false; >> + >> + if (guidcmp(&siglist->sig_type, &efi_guid_cert_x509_sha256)) { >> + /* TODO: other hash algos */ >> + debug("Certificate's digest type is not supported: %pUl\n", >> + &siglist->sig_type); >> + goto out; >> + } >> + >> + /* calculate hash of TBSCertificate */ >> + msg = calloc(1, SHA256_SUM_LEN); >> + if (!msg) { >> + debug("Out of memory\n"); >> + goto out; >> + } >> + >> + hash = calloc(1, SHA256_SUM_LEN); >> + if (!hash) { >> + debug("Out of memory\n"); >> + goto out; >> + } >> + >> + reg[0].data = cert->tbs; >> + reg[0].size = cert->tbs_size; >> + hash_calculate("sha256", reg, 1, msg); >> + >> + /* go through signature list */ >> + for (sig_data = siglist->sig_data_list; sig_data; >> + sig_data = sig_data->next) { >> + /* >> + * struct efi_cert_x509_sha256 { >> + * u8 tbs_hash[256/8]; >> + * time64_t revocation_time; >> + * }; >> + */ >> + if ((sig_data->size == SHA256_SUM_LEN) && >> + !memcmp(sig_data->data, hash, SHA256_SUM_LEN)) { >> + memcpy(revoc_time, sig_data->data + SHA256_SUM_LEN, >> + sizeof(*revoc_time)); >> + found = true; >> + goto out; >> + } >> + } >> + >> +out: >> + free(hash); >> + free(msg); >> + >> + return found; >> +} >> + >> +/** >> + * efi_signature_verify_cert - verify a certificate with dbx >> + * @cert: x509 certificate >> + * @dbx: Signature database >> + * >> + * Search signature database pointed to by @dbx and find a certificate >> + * pointed to by @cert. >> + * This function is expected to be used against "dbx". >> + * >> + * Return: true if a certificate is not rejected, false otherwise. >> + */ >> +bool efi_signature_verify_cert(struct x509_certificate *cert, >> + struct efi_signature_store *dbx) >> +{ >> + struct efi_signature_store *siglist; >> + time64_t revoc_time; >> + bool found = false; >> + >> + debug("%s: Enter, %p, %p\n", __func__, dbx, cert); >> + >> + if (!cert) >> + return false; >> + >> + for (siglist = dbx; siglist; siglist = siglist->next) { >> + if (efi_search_siglist(cert, siglist, &revoc_time)) { >> + /* TODO */ >> + /* compare signing time with revocation time */ >> + >> + found = true; >> + break; >> + } >> + } >> + >> + debug("%s: Exit, verified: %d\n", __func__, !found); >> + return !found; >> +} >> + >> +/** >> + * efi_signature_verify_signers - verify signers' certificates with dbx >> + * @msg: Signature >> + * @dbx: Signature database >> + * >> + * Determine if any of signers' certificates in @msg may be verified >> + * by any of certificates in signature database pointed to by @dbx. >> + * This function is expected to be used against "dbx". >> + * >> + * Return: true if none of certificates is rejected, false otherwise. >> + */ >> +bool efi_signature_verify_signers(struct pkcs7_message *msg, >> + struct efi_signature_store *dbx) >> +{ >> + struct pkcs7_signed_info *info; >> + bool found = false; >> + >> + debug("%s: Enter, %p, %p\n", __func__, msg, dbx); >> + >> + if (!msg) >> + goto out; >> + >> + for (info = msg->signed_infos; info; info = info->next) { >> + if (info->signer && >> + !efi_signature_verify_cert(info->signer, dbx)) { >> + found = true; >> + goto out; >> + } >> + } >> +out: >> + debug("%s: Exit, verified: %d\n", __func__, !found); >> + return !found; >> +} >> + >> +/** >> + * efi_image_region_add - add an entry of region >> + * @regs: Pointer to array of regions >> + * @start: Start address of region >> + * @end: End address of region >> + * @nocheck: flag against overlapped regions >> + * >> + * Take one entry of region [@start, @end] and append it to the list >> + * pointed to by @regs. If @nocheck is false, overlapping among entries >> + * will be checked first. >> + * >> + * Return: 0 on success, status code (negative) on error >> + */ >> +efi_status_t efi_image_region_add(struct efi_image_regions *regs, >> + const void *start, const void *end, >> + int nocheck) >> +{ >> + struct image_region *reg; >> + int i, j; >> + >> + if (regs->num >= regs->max) { >> + debug("%s: no more room for regions\n", __func__); >> + return EFI_OUT_OF_RESOURCES; >> + } >> + >> + if (end < start) >> + return EFI_INVALID_PARAMETER; >> + >> + for (i = 0; i < regs->num; i++) { >> + reg = ®s->reg[i]; >> + if (nocheck) >> + continue; >> + >> + if (start > reg->data + reg->size) >> + continue; >> + >> + if ((start >= reg->data && start < reg->data + reg->size) || >> + (end > reg->data && end < reg->data + reg->size)) { >> + debug("%s: new region already part of another\n", >> + __func__); >> + return EFI_INVALID_PARAMETER; >> + } >> + >> + if (start < reg->data && end < reg->data + reg->size) { >> + for (j = regs->num - 1; j >= i; j--) >> + memcpy(®s->reg[j], ®s->reg[j + 1], >> + sizeof(*reg)); >> + break; >> + } >> + } >> + >> + reg = ®s->reg[i]; >> + reg->data = start; >> + reg->size = end - start; >> + regs->num++; >> + >> + return EFI_SUCCESS; >> +} >> +#endif /* CONFIG_EFI_SECURE_BOOT */ >> > > If I define CONFIG_EFI_SECURE_BOOT I get a warning: > > lib/efi_loader/efi_signature.c: In function ?efi_hash_regions?: > lib/efi_loader/efi_signature.c:52:2: warning: implicit declaration of > function ?hash_calculate? [-Wimplicit-function-declaration] > 52 | hash_calculate("sha256", regs->reg, regs->num, *hash); > | ^~~~~~~~~~~~~~ > > > #include u-boot/rsa-checksum.h > seems to be missing in the code. The problem only occurs with an old version of your patch. Sorry. > > Best regards > > Heinrich >
On 4/14/20 4:51 AM, AKASHI Takahiro wrote: > In this commit, implemented are a couple of helper functions which will be > used to materialize variable authentication as well as image authentication > in later patches. > > Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org> > --- > include/efi_api.h | 87 +++++ > include/efi_loader.h | 72 ++++ > lib/efi_loader/Makefile | 1 + > lib/efi_loader/efi_signature.c | 583 +++++++++++++++++++++++++++++++++ > 4 files changed, 743 insertions(+) > create mode 100644 lib/efi_loader/efi_signature.c > > diff --git a/include/efi_api.h b/include/efi_api.h > index 1c40ffc4f56c..77d6bf2660b9 100644 > --- a/include/efi_api.h > +++ b/include/efi_api.h > @@ -18,6 +18,7 @@ > > #include <efi.h> > #include <charset.h> > +#include <pe.h> > > #ifdef CONFIG_EFI_LOADER > #include <asm/setjmp.h> > @@ -329,6 +330,10 @@ struct efi_runtime_services { > EFI_GUID(0x8be4df61, 0x93ca, 0x11d2, 0xaa, 0x0d, \ > 0x00, 0xe0, 0x98, 0x03, 0x2b, 0x8c) > > +#define EFI_IMAGE_SECURITY_DATABASE_GUID \ > + EFI_GUID(0xd719b2cb, 0x3d3a, 0x4596, 0xa3, 0xbc, \ > + 0xda, 0xd0, 0x0e, 0x67, 0x65, 0x6f) > + > #define EFI_FDT_GUID \ > EFI_GUID(0xb1b621d5, 0xf19c, 0x41a5, \ > 0x83, 0x0b, 0xd9, 0x15, 0x2c, 0x69, 0xaa, 0xe0) > @@ -1682,4 +1687,86 @@ struct efi_load_file_protocol { > #define LAST_ATTEMPT_STATUS_ERROR_UNSUCCESSFUL_VENDOR_RANGE_MIN 0x00001000 > #define LAST_ATTEMPT_STATUS_ERROR_UNSUCCESSFUL_VENDOR_RANGE_MAX 0x00004000 > > +/* Certificate types in signature database */ > +#define EFI_CERT_SHA256_GUID \ > + EFI_GUID(0xc1c41626, 0x504c, 0x4092, 0xac, 0xa9, \ > + 0x41, 0xf9, 0x36, 0x93, 0x43, 0x28) > +#define EFI_CERT_RSA2048_GUID \ > + EFI_GUID(0x3c5766e8, 0x269c, 0x4e34, 0xaa, 0x14, \ > + 0xed, 0x77, 0x6e, 0x85, 0xb3, 0xb6) > +#define EFI_CERT_X509_GUID \ > + EFI_GUID(0xa5c059a1, 0x94e4, 0x4aa7, 0x87, 0xb5, \ > + 0xab, 0x15, 0x5c, 0x2b, 0xf0, 0x72) > +#define EFI_CERT_X509_SHA256_GUID \ > + EFI_GUID(0x3bd2a492, 0x96c0, 0x4079, 0xb4, 0x20, \ > + 0xfc, 0xf9, 0x8e, 0xf1, 0x03, 0xed) > +#define EFI_CERT_TYPE_PKCS7_GUID \ > + EFI_GUID(0x4aafd29d, 0x68df, 0x49ee, 0x8a, 0xa9, \ > + 0x34, 0x7d, 0x37, 0x56, 0x65, 0xa7) > + > +/** > + * win_certificate_uefi_guid - A certificate that encapsulates > + * a GUID-specific signature > + * > + * @hdr: Windows certificate header > + * @cert_type: Certificate type > + * @cert_data: Certificate data > + */ > +struct win_certificate_uefi_guid { > + WIN_CERTIFICATE hdr; > + efi_guid_t cert_type; > + u8 cert_data[]; > +} __attribute__((__packed__)); > + > +/** > + * efi_variable_authentication_2 - A time-based authentication method > + * descriptor > + * > + * This structure describes an authentication information for > + * a variable with EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS > + * and should be included as part of a variable's value. > + * Only EFI_CERT_TYPE_PKCS7_GUID is accepted. > + * > + * @time_stamp: Descriptor's time stamp > + * @auth_info: Authentication info > + */ > +struct efi_variable_authentication_2 { > + struct efi_time time_stamp; > + struct win_certificate_uefi_guid auth_info; > +} __attribute__((__packed__)); > + > +/** > + * efi_signature_data - A format of signature > + * > + * This structure describes a single signature in signature database. > + * > + * @signature_owner: Signature owner > + * @signature_data: Signature data > + */ > +struct efi_signature_data { > + efi_guid_t signature_owner; > + u8 signature_data[]; > +} __attribute__((__packed__)); > + > +/** > + * efi_signature_list - A format of signature database > + * > + * This structure describes a list of signatures with the same type. > + * An authenticated variable's value is a concatenation of one or more > + * efi_signature_list's. > + * > + * @signature_type: Signature type > + * @signature_list_size: Size of signature list > + * @signature_header_size: Size of signature header > + * @signature_size: Size of signature > + */ > +struct efi_signature_list { > + efi_guid_t signature_type; > + u32 signature_list_size; > + u32 signature_header_size; > + u32 signature_size; > +/* u8 signature_header[signature_header_size]; */ > +/* struct efi_signature_data signatures[...][signature_size]; */ > +} __attribute__((__packed__)); > + > #endif > diff --git a/include/efi_loader.h b/include/efi_loader.h > index 3f2792892f34..8cf85d2fb7e2 100644 > --- a/include/efi_loader.h > +++ b/include/efi_loader.h > @@ -26,6 +26,7 @@ static inline void *guidcpy(void *dst, const void *src) > #if CONFIG_IS_ENABLED(EFI_LOADER) > > #include <linux/list.h> > +#include <linux/oid_registry.h> > > /* Maximum number of configuration tables */ > #define EFI_MAX_CONFIGURATION_TABLES 16 > @@ -178,6 +179,11 @@ extern const efi_guid_t efi_guid_hii_config_routing_protocol; > extern const efi_guid_t efi_guid_hii_config_access_protocol; > extern const efi_guid_t efi_guid_hii_database_protocol; > extern const efi_guid_t efi_guid_hii_string_protocol; > +/* GUIDs for authentication */ > +extern const efi_guid_t efi_guid_image_security_database; > +extern const efi_guid_t efi_guid_sha256; > +extern const efi_guid_t efi_guid_cert_x509; > +extern const efi_guid_t efi_guid_cert_x509_sha256; > > /* GUID of RNG protocol */ > extern const efi_guid_t efi_guid_rng_protocol; > @@ -680,6 +686,72 @@ void efi_deserialize_load_option(struct efi_load_option *lo, u8 *data); > unsigned long efi_serialize_load_option(struct efi_load_option *lo, u8 **data); > efi_status_t efi_bootmgr_load(efi_handle_t *handle); > > +#ifdef CONFIG_EFI_SECURE_BOOT > +#include <image.h> > + > +/** > + * efi_image_regions - A list of memory regions > + * > + * @max: Maximum number of regions > + * @num: Number of regions > + * @reg: array of regions > + */ > +struct efi_image_regions { > + int max; > + int num; > + struct image_region reg[]; > +}; > + > +/** > + * efi_sig_data - A decoded data of struct efi_signature_data > + * > + * This structure represents an internal form of signature in > + * signature database. A listed list may represent a signature list. > + * > + * @next: Pointer to next entry > + * @onwer: Signature owner > + * @data: Pointer to signature data > + * @size: Size of signature data > + */ > +struct efi_sig_data { > + struct efi_sig_data *next; > + efi_guid_t owner; > + void *data; > + size_t size; > +}; > + > +/** > + * efi_signature_store - A decoded data of signature database > + * > + * This structure represents an internal form of signature database. > + * > + * @next: Pointer to next entry > + * @sig_type: Signature type > + * @sig_data_list: Pointer to signature list > + */ > +struct efi_signature_store { > + struct efi_signature_store *next; > + efi_guid_t sig_type; > + struct efi_sig_data *sig_data_list; > +}; > + > +struct x509_certificate; > +struct pkcs7_message; > + > +bool efi_signature_verify_cert(struct x509_certificate *cert, > + struct efi_signature_store *dbx); > +bool efi_signature_verify_signers(struct pkcs7_message *msg, > + struct efi_signature_store *dbx); > +bool efi_signature_verify_with_sigdb(struct efi_image_regions *regs, > + struct pkcs7_message *msg, > + struct efi_signature_store *db, > + struct x509_certificate **cert); > + > +efi_status_t efi_image_region_add(struct efi_image_regions *regs, > + const void *start, const void *end, > + int nocheck); > +#endif /* CONFIG_EFI_SECURE_BOOT */ > + > #else /* CONFIG_IS_ENABLED(EFI_LOADER) */ > > /* Without CONFIG_EFI_LOADER we don't have a runtime section, stub it out */ > diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile > index 9b3b70447336..eff3c25ec301 100644 > --- a/lib/efi_loader/Makefile > +++ b/lib/efi_loader/Makefile > @@ -44,3 +44,4 @@ obj-$(CONFIG_GENERATE_ACPI_TABLE) += efi_acpi.o > obj-$(CONFIG_GENERATE_SMBIOS_TABLE) += efi_smbios.o > obj-$(CONFIG_EFI_RNG_PROTOCOL) += efi_rng.o > obj-$(CONFIG_EFI_LOAD_FILE2_INITRD) += efi_load_initrd.o > +obj-y += efi_signature.o > diff --git a/lib/efi_loader/efi_signature.c b/lib/efi_loader/efi_signature.c > new file mode 100644 > index 000000000000..23dac94c0593 > --- /dev/null > +++ b/lib/efi_loader/efi_signature.c > @@ -0,0 +1,583 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +/* > + * Copyright (c) 2018 Patrick Wildt <patrick at blueri.se> > + * Copyright (c) 2019 Linaro Limited, Author: AKASHI Takahiro > + */ > + > +#include <common.h> > +#include <charset.h> > +#include <efi_loader.h> > +#include <image.h> > +#include <hexdump.h> > +#include <malloc.h> > +#include <pe.h> > +#include <linux/compat.h> > +#include <linux/oid_registry.h> > +#include <u-boot/rsa.h> > +#include <u-boot/sha256.h> > +/* > + * avoid duplicated inclusion: > + * #include "../lib/crypto/x509_parser.h" > + */ > +#include "../lib/crypto/pkcs7_parser.h" > + > +const efi_guid_t efi_guid_image_security_database = > + EFI_IMAGE_SECURITY_DATABASE_GUID; > +const efi_guid_t efi_guid_sha256 = EFI_CERT_SHA256_GUID; > +const efi_guid_t efi_guid_cert_rsa2048 = EFI_CERT_RSA2048_GUID; > +const efi_guid_t efi_guid_cert_x509 = EFI_CERT_X509_GUID; > +const efi_guid_t efi_guid_cert_x509_sha256 = EFI_CERT_X509_SHA256_GUID; > + > +#ifdef CONFIG_EFI_SECURE_BOOT > + > +/** > + * efi_hash_regions - calculate a hash value > + * @regs: List of regions > + * @hash: Pointer to a pointer to buffer holding a hash value > + * @size: Size of buffer to be returned > + * > + * Calculate a sha256 value of @regs and return a value in @hash. > + * > + * Return: true on success, false on error > + */ > +static bool efi_hash_regions(struct efi_image_regions *regs, void **hash, > + size_t *size) > +{ > + *size = 0; > + *hash = calloc(1, SHA256_SUM_LEN); > + if (!*hash) { > + debug("Out of memory\n"); > + return false; > + } > + *size = SHA256_SUM_LEN; > + > + hash_calculate("sha256", regs->reg, regs->num, *hash); > +#ifdef DEBUG > + debug("hash calculated:\n"); > + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1, > + *hash, SHA256_SUM_LEN, false); > +#endif > + > + return true; > +} > + > +/** > + * efi_hash_msg_content - calculate a hash value of contentInfo > + * @msg: Signature > + * @hash: Pointer to a pointer to buffer holding a hash value > + * @size: Size of buffer to be returned > + * > + * Calculate a sha256 value of contentInfo in @msg and return a value in @hash. > + * > + * Return: true on success, false on error > + */ > +static bool efi_hash_msg_content(struct pkcs7_message *msg, void **hash, > + size_t *size) > +{ > + struct image_region regtmp; > + > + *size = 0; > + *hash = calloc(1, SHA256_SUM_LEN); > + if (!*hash) { > + debug("Out of memory\n"); > + free(msg); > + return false; > + } > + *size = SHA256_SUM_LEN; > + > + regtmp.data = msg->data; > + regtmp.size = msg->data_len; > + > + hash_calculate("sha256", ®tmp, 1, *hash); > +#ifdef DEBUG > + debug("hash calculated based on contentInfo:\n"); > + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1, > + *hash, SHA256_SUM_LEN, false); > +#endif > + > + return true; > +} > + > +/** > + * efi_signature_verify - verify a signature with a certificate > + * @regs: List of regions to be authenticated > + * @signed_info: Pointer to PKCS7's signed_info > + * @cert: x509 certificate > + * > + * Signature pointed to by @signed_info against image pointed to by @regs > + * is verified by a certificate pointed to by @cert. > + * @signed_info holds a signature, including a message digest which is to be > + * compared with a hash value calculated from @regs. > + * > + * Return: true if signature is verified, false if not > + */ > +static bool efi_signature_verify(struct efi_image_regions *regs, > + struct pkcs7_message *msg, > + struct pkcs7_signed_info *ps_info, > + struct x509_certificate *cert) > +{ > + struct image_sign_info info; > + struct image_region regtmp[2]; > + void *hash; > + size_t size; > + char c; > + bool verified; > + > + debug("%s: Enter, %p, %p, %p(issuer: %s, subject: %s)\n", __func__, > + regs, ps_info, cert, cert->issuer, cert->subject); > + > + verified = false; > + > + memset(&info, '\0', sizeof(info)); > + info.padding = image_get_padding_algo("pkcs-1.5"); > + /* > + * Note: image_get_[checksum|crypto]_algo takes an string > + * argument like "<checksum>,<crypto>" > + * TODO: support other hash algorithms > + */ > + if (!strcmp(ps_info->sig->hash_algo, "sha1")) { There is a call efi_signature_verify_with_list(regs, NULL, NULL, siglist, cert) So ps_info may be NULL > + info.checksum = image_get_checksum_algo("sha1,rsa2048"); > + info.name = "sha1,rsa2048"; > + } else if (!strcmp(ps_info->sig->hash_algo, "sha256")) { > + info.checksum = image_get_checksum_algo("sha256,rsa2048"); > + info.name = "sha256,rsa2048"; > + } else { > + debug("unknown msg digest algo: %s\n", ps_info->sig->hash_algo); > + goto out; > + } > + info.crypto = image_get_crypto_algo(info.name); > + > + info.key = cert->pub->key; > + info.keylen = cert->pub->keylen; > + > + /* verify signature */ > + debug("%s: crypto: %s, signature len:%x\n", __func__, > + info.name, ps_info->sig->s_size); > + if (ps_info->aa_set & (1UL << sinfo_has_message_digest)) { There is a call efi_signature_verify_with_list(regs, NULL, NULL, siglist, cert) So ps_info may be NULL > + debug("%s: RSA verify authentication attribute\n", __func__); > + /* > + * NOTE: This path will be executed only for > + * PE image authentication > + */ > + > + /* check if hash matches digest first */ > + debug("checking msg digest first, len:0x%x\n", > + ps_info->msgdigest_len); > + > +#ifdef DEBUG > + debug("hash in database:\n"); > + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1, > + ps_info->msgdigest, ps_info->msgdigest_len, > + false); > +#endif > + /* against contentInfo first */ > + if ((msg->data && efi_hash_msg_content(msg, &hash, &size)) || > + /* for signed image */ There is a call efi_signature_verify_with_list(regs, NULL, NULL, siglist, cert) So msg may be NULL. Either avoid the call will NULL or check the parameters before dereferencing. Please, provide a follow up patch. I used cppcheck to identify this problem. Best regards Heinrich > + efi_hash_regions(regs, &hash, &size)) { > + /* for authenticated variable */ > + if (ps_info->msgdigest_len != size || > + memcmp(hash, ps_info->msgdigest, size)) { > + debug("Digest doesn't match\n"); > + free(hash); > + goto out; > + } > + > + free(hash); > + } else { > + debug("Digesting image failed\n"); > + goto out; > + } > + > + /* against digest */ > + c = 0x31; > + regtmp[0].data = &c; > + regtmp[0].size = 1; > + regtmp[1].data = ps_info->authattrs; > + regtmp[1].size = ps_info->authattrs_len; > + > + if (!rsa_verify(&info, regtmp, 2, > + ps_info->sig->s, ps_info->sig->s_size)) > + verified = true; > + } else { > + debug("%s: RSA verify content data\n", __func__); > + /* against all data */ > + if (!rsa_verify(&info, regs->reg, regs->num, > + ps_info->sig->s, ps_info->sig->s_size)) > + verified = true; > + } > + > +out: > + debug("%s: Exit, verified: %d\n", __func__, verified); > + return verified; > +} > + > +/** > + * efi_signature_verify_with_list - verify a signature with signature list > + * @regs: List of regions to be authenticated > + * @msg: Signature > + * @signed_info: Pointer to PKCS7's signed_info > + * @siglist: Signature list for certificates > + * @valid_cert: x509 certificate that verifies this signature > + * > + * Signature pointed to by @signed_info against image pointed to by @regs > + * is verified by signature list pointed to by @siglist. > + * Signature database is a simple concatenation of one or more > + * signature list(s). > + * > + * Return: true if signature is verified, false if not > + */ > +static > +bool efi_signature_verify_with_list(struct efi_image_regions *regs, > + struct pkcs7_message *msg, > + struct pkcs7_signed_info *signed_info, > + struct efi_signature_store *siglist, > + struct x509_certificate **valid_cert) > +{ > + struct x509_certificate *cert; > + struct efi_sig_data *sig_data; > + bool verified = false; > + > + debug("%s: Enter, %p, %p, %p, %p\n", __func__, > + regs, signed_info, siglist, valid_cert); > + > + if (!signed_info) { > + void *hash; > + size_t size; > + > + debug("%s: unsigned image\n", __func__); > + /* > + * verify based on calculated hash value > + * TODO: support other hash algorithms > + */ > + if (guidcmp(&siglist->sig_type, &efi_guid_sha256)) { > + debug("Digest algorithm is not supported: %pUl\n", > + &siglist->sig_type); > + goto out; > + } > + > + if (!efi_hash_regions(regs, &hash, &size)) { > + debug("Digesting unsigned image failed\n"); > + goto out; > + } > + > + /* go through the list */ > + for (sig_data = siglist->sig_data_list; sig_data; > + sig_data = sig_data->next) { > +#ifdef DEBUG > + debug("Msg digest in database:\n"); > + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1, > + sig_data->data, sig_data->size, false); > +#endif > + if ((sig_data->size == size) && > + !memcmp(sig_data->data, hash, size)) { > + verified = true; > + free(hash); > + goto out; > + } > + } > + free(hash); > + goto out; > + } > + > + debug("%s: signed image\n", __func__); > + if (guidcmp(&siglist->sig_type, &efi_guid_cert_x509)) { > + debug("Signature type is not supported: %pUl\n", > + &siglist->sig_type); > + goto out; > + } > + > + /* go through the list */ > + for (sig_data = siglist->sig_data_list; sig_data; > + sig_data = sig_data->next) { > + /* TODO: support owner check based on policy */ > + > + cert = x509_cert_parse(sig_data->data, sig_data->size); > + if (IS_ERR(cert)) { > + debug("Parsing x509 certificate failed\n"); > + goto out; > + } > + > + verified = efi_signature_verify(regs, msg, signed_info, cert); > + > + if (verified) { > + if (valid_cert) > + *valid_cert = cert; > + else > + x509_free_certificate(cert); > + break; > + } > + x509_free_certificate(cert); > + } > + > +out: > + debug("%s: Exit, verified: %d\n", __func__, verified); > + return verified; > +} > + > +/** > + * efi_signature_verify_with_sigdb - verify a signature with db > + * @regs: List of regions to be authenticated > + * @msg: Signature > + * @db: Signature database for trusted certificates > + * @cert: x509 certificate that verifies this signature > + * > + * Signature pointed to by @msg against image pointed to by @regs > + * is verified by signature database pointed to by @db. > + * > + * Return: true if signature is verified, false if not > + */ > +bool efi_signature_verify_with_sigdb(struct efi_image_regions *regs, > + struct pkcs7_message *msg, > + struct efi_signature_store *db, > + struct x509_certificate **cert) > +{ > + struct pkcs7_signed_info *info; > + struct efi_signature_store *siglist; > + bool verified = false; > + > + debug("%s: Enter, %p, %p, %p, %p\n", __func__, regs, msg, db, cert); > + > + if (!db) > + goto out; > + > + if (!db->sig_data_list) > + goto out; > + > + /* for unsigned image */ > + if (!msg) { > + debug("%s: Verify unsigned image with db\n", __func__); > + for (siglist = db; siglist; siglist = siglist->next) > + if (efi_signature_verify_with_list(regs, NULL, NULL, > + siglist, cert)) { > + verified = true; > + goto out; > + } > + > + goto out; > + } > + > + /* for signed image or variable */ > + debug("%s: Verify signed image with db\n", __func__); > + for (info = msg->signed_infos; info; info = info->next) { > + debug("Signed Info: digest algo: %s, pkey algo: %s\n", > + info->sig->hash_algo, info->sig->pkey_algo); > + > + for (siglist = db; siglist; siglist = siglist->next) { > + if (efi_signature_verify_with_list(regs, msg, info, > + siglist, cert)) { > + verified = true; > + goto out; > + } > + } > + } > + > +out: > + debug("%s: Exit, verified: %d\n", __func__, verified); > + return verified; > +} > + > +/** > + * efi_search_siglist - search signature list for a certificate > + * @cert: x509 certificate > + * @siglist: Signature list > + * @revoc_time: Pointer to buffer for revocation time > + * > + * Search signature list pointed to by @siglist and find a certificate > + * pointed to by @cert. > + * If found, revocation time that is specified in signature database is > + * returned in @revoc_time. > + * > + * Return: true if certificate is found, false if not > + */ > +static bool efi_search_siglist(struct x509_certificate *cert, > + struct efi_signature_store *siglist, > + time64_t *revoc_time) > +{ > + struct image_region reg[1]; > + void *hash = NULL, *msg = NULL; > + struct efi_sig_data *sig_data; > + bool found = false; > + > + /* can be null */ > + if (!siglist->sig_data_list) > + return false; > + > + if (guidcmp(&siglist->sig_type, &efi_guid_cert_x509_sha256)) { > + /* TODO: other hash algos */ > + debug("Certificate's digest type is not supported: %pUl\n", > + &siglist->sig_type); > + goto out; > + } > + > + /* calculate hash of TBSCertificate */ > + msg = calloc(1, SHA256_SUM_LEN); > + if (!msg) { > + debug("Out of memory\n"); > + goto out; > + } > + > + hash = calloc(1, SHA256_SUM_LEN); > + if (!hash) { > + debug("Out of memory\n"); > + goto out; > + } > + > + reg[0].data = cert->tbs; > + reg[0].size = cert->tbs_size; > + hash_calculate("sha256", reg, 1, msg); > + > + /* go through signature list */ > + for (sig_data = siglist->sig_data_list; sig_data; > + sig_data = sig_data->next) { > + /* > + * struct efi_cert_x509_sha256 { > + * u8 tbs_hash[256/8]; > + * time64_t revocation_time; > + * }; > + */ > + if ((sig_data->size == SHA256_SUM_LEN) && > + !memcmp(sig_data->data, hash, SHA256_SUM_LEN)) { > + memcpy(revoc_time, sig_data->data + SHA256_SUM_LEN, > + sizeof(*revoc_time)); > + found = true; > + goto out; > + } > + } > + > +out: > + free(hash); > + free(msg); > + > + return found; > +} > + > +/** > + * efi_signature_verify_cert - verify a certificate with dbx > + * @cert: x509 certificate > + * @dbx: Signature database > + * > + * Search signature database pointed to by @dbx and find a certificate > + * pointed to by @cert. > + * This function is expected to be used against "dbx". > + * > + * Return: true if a certificate is not rejected, false otherwise. > + */ > +bool efi_signature_verify_cert(struct x509_certificate *cert, > + struct efi_signature_store *dbx) > +{ > + struct efi_signature_store *siglist; > + time64_t revoc_time; > + bool found = false; > + > + debug("%s: Enter, %p, %p\n", __func__, dbx, cert); > + > + if (!cert) > + return false; > + > + for (siglist = dbx; siglist; siglist = siglist->next) { > + if (efi_search_siglist(cert, siglist, &revoc_time)) { > + /* TODO */ > + /* compare signing time with revocation time */ > + > + found = true; > + break; > + } > + } > + > + debug("%s: Exit, verified: %d\n", __func__, !found); > + return !found; > +} > + > +/** > + * efi_signature_verify_signers - verify signers' certificates with dbx > + * @msg: Signature > + * @dbx: Signature database > + * > + * Determine if any of signers' certificates in @msg may be verified > + * by any of certificates in signature database pointed to by @dbx. > + * This function is expected to be used against "dbx". > + * > + * Return: true if none of certificates is rejected, false otherwise. > + */ > +bool efi_signature_verify_signers(struct pkcs7_message *msg, > + struct efi_signature_store *dbx) > +{ > + struct pkcs7_signed_info *info; > + bool found = false; > + > + debug("%s: Enter, %p, %p\n", __func__, msg, dbx); > + > + if (!msg) > + goto out; > + > + for (info = msg->signed_infos; info; info = info->next) { > + if (info->signer && > + !efi_signature_verify_cert(info->signer, dbx)) { > + found = true; > + goto out; > + } > + } > +out: > + debug("%s: Exit, verified: %d\n", __func__, !found); > + return !found; > +} > + > +/** > + * efi_image_region_add - add an entry of region > + * @regs: Pointer to array of regions > + * @start: Start address of region > + * @end: End address of region > + * @nocheck: flag against overlapped regions > + * > + * Take one entry of region [@start, @end] and append it to the list > + * pointed to by @regs. If @nocheck is false, overlapping among entries > + * will be checked first. > + * > + * Return: 0 on success, status code (negative) on error > + */ > +efi_status_t efi_image_region_add(struct efi_image_regions *regs, > + const void *start, const void *end, > + int nocheck) > +{ > + struct image_region *reg; > + int i, j; > + > + if (regs->num >= regs->max) { > + debug("%s: no more room for regions\n", __func__); > + return EFI_OUT_OF_RESOURCES; > + } > + > + if (end < start) > + return EFI_INVALID_PARAMETER; > + > + for (i = 0; i < regs->num; i++) { > + reg = ®s->reg[i]; > + if (nocheck) > + continue; > + > + if (start > reg->data + reg->size) > + continue; > + > + if ((start >= reg->data && start < reg->data + reg->size) || > + (end > reg->data && end < reg->data + reg->size)) { > + debug("%s: new region already part of another\n", > + __func__); > + return EFI_INVALID_PARAMETER; > + } > + > + if (start < reg->data && end < reg->data + reg->size) { > + for (j = regs->num - 1; j >= i; j--) > + memcpy(®s->reg[j], ®s->reg[j + 1], > + sizeof(*reg)); > + break; > + } > + } > + > + reg = ®s->reg[i]; > + reg->data = start; > + reg->size = end - start; > + regs->num++; > + > + return EFI_SUCCESS; > +} > +#endif /* CONFIG_EFI_SECURE_BOOT */ >
Heinrich, On Tue, Apr 14, 2020 at 04:36:19PM +0200, Heinrich Schuchardt wrote: > On 2020-04-14 04:51, AKASHI Takahiro wrote: > > In this commit, implemented are a couple of helper functions which will be > > used to materialize variable authentication as well as image authentication > > in later patches. > > > > Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org> > > --- > > include/efi_api.h | 87 +++++ > > include/efi_loader.h | 72 ++++ > > lib/efi_loader/Makefile | 1 + > > lib/efi_loader/efi_signature.c | 583 +++++++++++++++++++++++++++++++++ > > 4 files changed, 743 insertions(+) > > create mode 100644 lib/efi_loader/efi_signature.c > > > > diff --git a/include/efi_api.h b/include/efi_api.h > > index 1c40ffc4f56c..77d6bf2660b9 100644 > > --- a/include/efi_api.h > > +++ b/include/efi_api.h > > @@ -18,6 +18,7 @@ > > > > #include <efi.h> > > #include <charset.h> > > +#include <pe.h> > > > > #ifdef CONFIG_EFI_LOADER > > #include <asm/setjmp.h> > > @@ -329,6 +330,10 @@ struct efi_runtime_services { > > EFI_GUID(0x8be4df61, 0x93ca, 0x11d2, 0xaa, 0x0d, \ > > 0x00, 0xe0, 0x98, 0x03, 0x2b, 0x8c) > > > > +#define EFI_IMAGE_SECURITY_DATABASE_GUID \ > > + EFI_GUID(0xd719b2cb, 0x3d3a, 0x4596, 0xa3, 0xbc, \ > > + 0xda, 0xd0, 0x0e, 0x67, 0x65, 0x6f) > > + > > #define EFI_FDT_GUID \ > > EFI_GUID(0xb1b621d5, 0xf19c, 0x41a5, \ > > 0x83, 0x0b, 0xd9, 0x15, 0x2c, 0x69, 0xaa, 0xe0) > > @@ -1682,4 +1687,86 @@ struct efi_load_file_protocol { > > #define LAST_ATTEMPT_STATUS_ERROR_UNSUCCESSFUL_VENDOR_RANGE_MIN 0x00001000 > > #define LAST_ATTEMPT_STATUS_ERROR_UNSUCCESSFUL_VENDOR_RANGE_MAX 0x00004000 > > > > +/* Certificate types in signature database */ > > +#define EFI_CERT_SHA256_GUID \ > > + EFI_GUID(0xc1c41626, 0x504c, 0x4092, 0xac, 0xa9, \ > > + 0x41, 0xf9, 0x36, 0x93, 0x43, 0x28) > > +#define EFI_CERT_RSA2048_GUID \ > > + EFI_GUID(0x3c5766e8, 0x269c, 0x4e34, 0xaa, 0x14, \ > > + 0xed, 0x77, 0x6e, 0x85, 0xb3, 0xb6) > > +#define EFI_CERT_X509_GUID \ > > + EFI_GUID(0xa5c059a1, 0x94e4, 0x4aa7, 0x87, 0xb5, \ > > + 0xab, 0x15, 0x5c, 0x2b, 0xf0, 0x72) > > +#define EFI_CERT_X509_SHA256_GUID \ > > + EFI_GUID(0x3bd2a492, 0x96c0, 0x4079, 0xb4, 0x20, \ > > + 0xfc, 0xf9, 0x8e, 0xf1, 0x03, 0xed) > > +#define EFI_CERT_TYPE_PKCS7_GUID \ > > + EFI_GUID(0x4aafd29d, 0x68df, 0x49ee, 0x8a, 0xa9, \ > > + 0x34, 0x7d, 0x37, 0x56, 0x65, 0xa7) > > + > > +/** > > + * win_certificate_uefi_guid - A certificate that encapsulates > > + * a GUID-specific signature > > + * > > + * @hdr: Windows certificate header > > + * @cert_type: Certificate type > > + * @cert_data: Certificate data > > + */ > > +struct win_certificate_uefi_guid { > > + WIN_CERTIFICATE hdr; > > + efi_guid_t cert_type; > > + u8 cert_data[]; > > +} __attribute__((__packed__)); > > + > > +/** > > + * efi_variable_authentication_2 - A time-based authentication method > > + * descriptor > > + * > > + * This structure describes an authentication information for > > + * a variable with EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS > > + * and should be included as part of a variable's value. > > + * Only EFI_CERT_TYPE_PKCS7_GUID is accepted. > > + * > > + * @time_stamp: Descriptor's time stamp > > + * @auth_info: Authentication info > > + */ > > +struct efi_variable_authentication_2 { > > + struct efi_time time_stamp; > > + struct win_certificate_uefi_guid auth_info; > > +} __attribute__((__packed__)); > > + > > +/** > > + * efi_signature_data - A format of signature > > + * > > + * This structure describes a single signature in signature database. > > + * > > + * @signature_owner: Signature owner > > + * @signature_data: Signature data > > + */ > > +struct efi_signature_data { > > + efi_guid_t signature_owner; > > + u8 signature_data[]; > > Please, use [0]. Actually, there are a bunch of uses of [] notation in efi.h, efi_api.h and efi_loader.h. Do you really want to modify all? > > +} __attribute__((__packed__)); > > + > > +/** > > + * efi_signature_list - A format of signature database > > + * > > + * This structure describes a list of signatures with the same type. > > + * An authenticated variable's value is a concatenation of one or more > > + * efi_signature_list's. > > + * > > + * @signature_type: Signature type > > + * @signature_list_size: Size of signature list > > + * @signature_header_size: Size of signature header > > + * @signature_size: Size of signature > > + */ > > +struct efi_signature_list { > > + efi_guid_t signature_type; > > + u32 signature_list_size; > > + u32 signature_header_size; > > + u32 signature_size; > > +/* u8 signature_header[signature_header_size]; */ > > +/* struct efi_signature_data signatures[...][signature_size]; */ > > +} __attribute__((__packed__)); > > + > > #endif > > diff --git a/include/efi_loader.h b/include/efi_loader.h > > index 3f2792892f34..8cf85d2fb7e2 100644 > > --- a/include/efi_loader.h > > +++ b/include/efi_loader.h > > @@ -26,6 +26,7 @@ static inline void *guidcpy(void *dst, const void *src) > > #if CONFIG_IS_ENABLED(EFI_LOADER) > > > > #include <linux/list.h> > > +#include <linux/oid_registry.h> > > > > /* Maximum number of configuration tables */ > > #define EFI_MAX_CONFIGURATION_TABLES 16 > > @@ -178,6 +179,11 @@ extern const efi_guid_t efi_guid_hii_config_routing_protocol; > > extern const efi_guid_t efi_guid_hii_config_access_protocol; > > extern const efi_guid_t efi_guid_hii_database_protocol; > > extern const efi_guid_t efi_guid_hii_string_protocol; > > +/* GUIDs for authentication */ > > +extern const efi_guid_t efi_guid_image_security_database; > > +extern const efi_guid_t efi_guid_sha256; > > +extern const efi_guid_t efi_guid_cert_x509; > > +extern const efi_guid_t efi_guid_cert_x509_sha256; > > > > /* GUID of RNG protocol */ > > extern const efi_guid_t efi_guid_rng_protocol; > > @@ -680,6 +686,72 @@ void efi_deserialize_load_option(struct efi_load_option *lo, u8 *data); > > unsigned long efi_serialize_load_option(struct efi_load_option *lo, u8 **data); > > efi_status_t efi_bootmgr_load(efi_handle_t *handle); > > > > +#ifdef CONFIG_EFI_SECURE_BOOT > > +#include <image.h> > > + > > +/** > > + * efi_image_regions - A list of memory regions > > + * > > + * @max: Maximum number of regions > > + * @num: Number of regions > > + * @reg: array of regions > > + */ > > +struct efi_image_regions { > > + int max; > > + int num; > > + struct image_region reg[]; > > +}; > > + > > +/** > > + * efi_sig_data - A decoded data of struct efi_signature_data > > + * > > + * This structure represents an internal form of signature in > > + * signature database. A listed list may represent a signature list. > > + * > > + * @next: Pointer to next entry > > + * @onwer: Signature owner > > + * @data: Pointer to signature data > > + * @size: Size of signature data > > + */ > > +struct efi_sig_data { > > + struct efi_sig_data *next; > > + efi_guid_t owner; > > + void *data; > > + size_t size; > > +}; > > + > > +/** > > + * efi_signature_store - A decoded data of signature database > > + * > > + * This structure represents an internal form of signature database. > > + * > > + * @next: Pointer to next entry > > + * @sig_type: Signature type > > + * @sig_data_list: Pointer to signature list > > + */ > > +struct efi_signature_store { > > + struct efi_signature_store *next; > > + efi_guid_t sig_type; > > + struct efi_sig_data *sig_data_list; > > +}; > > + > > +struct x509_certificate; > > +struct pkcs7_message; > > + > > +bool efi_signature_verify_cert(struct x509_certificate *cert, > > + struct efi_signature_store *dbx); > > +bool efi_signature_verify_signers(struct pkcs7_message *msg, > > + struct efi_signature_store *dbx); > > +bool efi_signature_verify_with_sigdb(struct efi_image_regions *regs, > > + struct pkcs7_message *msg, > > + struct efi_signature_store *db, > > + struct x509_certificate **cert); > > + > > +efi_status_t efi_image_region_add(struct efi_image_regions *regs, > > + const void *start, const void *end, > > + int nocheck); > > +#endif /* CONFIG_EFI_SECURE_BOOT */ > > + > > #else /* CONFIG_IS_ENABLED(EFI_LOADER) */ > > > > /* Without CONFIG_EFI_LOADER we don't have a runtime section, stub it out */ > > diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile > > index 9b3b70447336..eff3c25ec301 100644 > > --- a/lib/efi_loader/Makefile > > +++ b/lib/efi_loader/Makefile > > @@ -44,3 +44,4 @@ obj-$(CONFIG_GENERATE_ACPI_TABLE) += efi_acpi.o > > obj-$(CONFIG_GENERATE_SMBIOS_TABLE) += efi_smbios.o > > obj-$(CONFIG_EFI_RNG_PROTOCOL) += efi_rng.o > > obj-$(CONFIG_EFI_LOAD_FILE2_INITRD) += efi_load_initrd.o > > +obj-y += efi_signature.o > > diff --git a/lib/efi_loader/efi_signature.c b/lib/efi_loader/efi_signature.c > > new file mode 100644 > > index 000000000000..23dac94c0593 > > --- /dev/null > > +++ b/lib/efi_loader/efi_signature.c > > @@ -0,0 +1,583 @@ > > +// SPDX-License-Identifier: GPL-2.0+ > > +/* > > + * Copyright (c) 2018 Patrick Wildt <patrick at blueri.se> > > + * Copyright (c) 2019 Linaro Limited, Author: AKASHI Takahiro > > + */ > > + > > +#include <common.h> > > +#include <charset.h> > > +#include <efi_loader.h> > > +#include <image.h> > > +#include <hexdump.h> > > +#include <malloc.h> > > +#include <pe.h> > > You just added pe.h to efi_api.h which is included in efi_loader.h. > Please, avoid adding the includes twice. I agree as there is no use of any symbols from pe.h here. > > +#include <linux/compat.h> > > +#include <linux/oid_registry.h> > > +#include <u-boot/rsa.h> > > +#include <u-boot/sha256.h> > > +/* > > + * avoid duplicated inclusion: > > Why don't you fix the lib/crypto/x509_parser.h that you created? Just > add the missing > > #ifdef _X509_PARSER_H > #define _X509_PARSER_H > #endif /* _X509_PARSER_H */ Okay. > Same problem in pkcs7_parser.h. > > > + * #include "../lib/crypto/x509_parser.h" > > + */ > > If you patch is working I see no reason to add the comment here. > > > +#include "../lib/crypto/pkcs7_parser.h" > > Why is pkcs7_parser.h in lib/ and not in include/? > > I would prefer to avoid relative paths. My basic approach was to minimize the modification to the original (i.e. linux code) as much as possible. Anyhow, I will try to fix it. Thanks, -Takahiro Akashi > I will remove the superfluous comment and include when merging. The rest > can be fixed later. > > Best regards > > Heinrich > > > + > > +const efi_guid_t efi_guid_image_security_database = > > + EFI_IMAGE_SECURITY_DATABASE_GUID; > > +const efi_guid_t efi_guid_sha256 = EFI_CERT_SHA256_GUID; > > +const efi_guid_t efi_guid_cert_rsa2048 = EFI_CERT_RSA2048_GUID; > > +const efi_guid_t efi_guid_cert_x509 = EFI_CERT_X509_GUID; > > +const efi_guid_t efi_guid_cert_x509_sha256 = EFI_CERT_X509_SHA256_GUID; > > + > > +#ifdef CONFIG_EFI_SECURE_BOOT > > + > > +/** > > + * efi_hash_regions - calculate a hash value > > + * @regs: List of regions > > + * @hash: Pointer to a pointer to buffer holding a hash value > > + * @size: Size of buffer to be returned > > + * > > + * Calculate a sha256 value of @regs and return a value in @hash. > > + * > > + * Return: true on success, false on error > > + */ > > +static bool efi_hash_regions(struct efi_image_regions *regs, void **hash, > > + size_t *size) > > +{ > > + *size = 0; > > + *hash = calloc(1, SHA256_SUM_LEN); > > + if (!*hash) { > > + debug("Out of memory\n"); > > + return false; > > + } > > + *size = SHA256_SUM_LEN; > > + > > + hash_calculate("sha256", regs->reg, regs->num, *hash); > > +#ifdef DEBUG > > + debug("hash calculated:\n"); > > + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1, > > + *hash, SHA256_SUM_LEN, false); > > +#endif > > + > > + return true; > > +} > > + > > +/** > > + * efi_hash_msg_content - calculate a hash value of contentInfo > > + * @msg: Signature > > + * @hash: Pointer to a pointer to buffer holding a hash value > > + * @size: Size of buffer to be returned > > + * > > + * Calculate a sha256 value of contentInfo in @msg and return a value in @hash. > > + * > > + * Return: true on success, false on error > > + */ > > +static bool efi_hash_msg_content(struct pkcs7_message *msg, void **hash, > > + size_t *size) > > +{ > > + struct image_region regtmp; > > + > > + *size = 0; > > + *hash = calloc(1, SHA256_SUM_LEN); > > + if (!*hash) { > > + debug("Out of memory\n"); > > + free(msg); > > + return false; > > + } > > + *size = SHA256_SUM_LEN; > > + > > + regtmp.data = msg->data; > > + regtmp.size = msg->data_len; > > + > > + hash_calculate("sha256", ®tmp, 1, *hash); > > +#ifdef DEBUG > > + debug("hash calculated based on contentInfo:\n"); > > + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1, > > + *hash, SHA256_SUM_LEN, false); > > +#endif > > + > > + return true; > > +} > > + > > +/** > > + * efi_signature_verify - verify a signature with a certificate > > + * @regs: List of regions to be authenticated > > + * @signed_info: Pointer to PKCS7's signed_info > > + * @cert: x509 certificate > > + * > > + * Signature pointed to by @signed_info against image pointed to by @regs > > + * is verified by a certificate pointed to by @cert. > > + * @signed_info holds a signature, including a message digest which is to be > > + * compared with a hash value calculated from @regs. > > + * > > + * Return: true if signature is verified, false if not > > + */ > > +static bool efi_signature_verify(struct efi_image_regions *regs, > > + struct pkcs7_message *msg, > > + struct pkcs7_signed_info *ps_info, > > + struct x509_certificate *cert) > > +{ > > + struct image_sign_info info; > > + struct image_region regtmp[2]; > > + void *hash; > > + size_t size; > > + char c; > > + bool verified; > > + > > + debug("%s: Enter, %p, %p, %p(issuer: %s, subject: %s)\n", __func__, > > + regs, ps_info, cert, cert->issuer, cert->subject); > > + > > + verified = false; > > + > > + memset(&info, '\0', sizeof(info)); > > + info.padding = image_get_padding_algo("pkcs-1.5"); > > + /* > > + * Note: image_get_[checksum|crypto]_algo takes an string > > + * argument like "<checksum>,<crypto>" > > + * TODO: support other hash algorithms > > + */ > > + if (!strcmp(ps_info->sig->hash_algo, "sha1")) { > > + info.checksum = image_get_checksum_algo("sha1,rsa2048"); > > + info.name = "sha1,rsa2048"; > > + } else if (!strcmp(ps_info->sig->hash_algo, "sha256")) { > > + info.checksum = image_get_checksum_algo("sha256,rsa2048"); > > + info.name = "sha256,rsa2048"; > > + } else { > > + debug("unknown msg digest algo: %s\n", ps_info->sig->hash_algo); > > + goto out; > > + } > > + info.crypto = image_get_crypto_algo(info.name); > > + > > + info.key = cert->pub->key; > > + info.keylen = cert->pub->keylen; > > + > > + /* verify signature */ > > + debug("%s: crypto: %s, signature len:%x\n", __func__, > > + info.name, ps_info->sig->s_size); > > + if (ps_info->aa_set & (1UL << sinfo_has_message_digest)) { > > + debug("%s: RSA verify authentication attribute\n", __func__); > > + /* > > + * NOTE: This path will be executed only for > > + * PE image authentication > > + */ > > + > > + /* check if hash matches digest first */ > > + debug("checking msg digest first, len:0x%x\n", > > + ps_info->msgdigest_len); > > + > > +#ifdef DEBUG > > + debug("hash in database:\n"); > > + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1, > > + ps_info->msgdigest, ps_info->msgdigest_len, > > + false); > > +#endif > > + /* against contentInfo first */ > > + if ((msg->data && efi_hash_msg_content(msg, &hash, &size)) || > > + /* for signed image */ > > + efi_hash_regions(regs, &hash, &size)) { > > + /* for authenticated variable */ > > + if (ps_info->msgdigest_len != size || > > + memcmp(hash, ps_info->msgdigest, size)) { > > + debug("Digest doesn't match\n"); > > + free(hash); > > + goto out; > > + } > > + > > + free(hash); > > + } else { > > + debug("Digesting image failed\n"); > > + goto out; > > + } > > + > > + /* against digest */ > > + c = 0x31; > > + regtmp[0].data = &c; > > + regtmp[0].size = 1; > > + regtmp[1].data = ps_info->authattrs; > > + regtmp[1].size = ps_info->authattrs_len; > > + > > + if (!rsa_verify(&info, regtmp, 2, > > + ps_info->sig->s, ps_info->sig->s_size)) > > + verified = true; > > + } else { > > + debug("%s: RSA verify content data\n", __func__); > > + /* against all data */ > > + if (!rsa_verify(&info, regs->reg, regs->num, > > + ps_info->sig->s, ps_info->sig->s_size)) > > + verified = true; > > + } > > + > > +out: > > + debug("%s: Exit, verified: %d\n", __func__, verified); > > + return verified; > > +} > > + > > +/** > > + * efi_signature_verify_with_list - verify a signature with signature list > > + * @regs: List of regions to be authenticated > > + * @msg: Signature > > + * @signed_info: Pointer to PKCS7's signed_info > > + * @siglist: Signature list for certificates > > + * @valid_cert: x509 certificate that verifies this signature > > + * > > + * Signature pointed to by @signed_info against image pointed to by @regs > > + * is verified by signature list pointed to by @siglist. > > + * Signature database is a simple concatenation of one or more > > + * signature list(s). > > + * > > + * Return: true if signature is verified, false if not > > + */ > > +static > > +bool efi_signature_verify_with_list(struct efi_image_regions *regs, > > + struct pkcs7_message *msg, > > + struct pkcs7_signed_info *signed_info, > > + struct efi_signature_store *siglist, > > + struct x509_certificate **valid_cert) > > +{ > > + struct x509_certificate *cert; > > + struct efi_sig_data *sig_data; > > + bool verified = false; > > + > > + debug("%s: Enter, %p, %p, %p, %p\n", __func__, > > + regs, signed_info, siglist, valid_cert); > > + > > + if (!signed_info) { > > + void *hash; > > + size_t size; > > + > > + debug("%s: unsigned image\n", __func__); > > + /* > > + * verify based on calculated hash value > > + * TODO: support other hash algorithms > > + */ > > + if (guidcmp(&siglist->sig_type, &efi_guid_sha256)) { > > + debug("Digest algorithm is not supported: %pUl\n", > > + &siglist->sig_type); > > + goto out; > > + } > > + > > + if (!efi_hash_regions(regs, &hash, &size)) { > > + debug("Digesting unsigned image failed\n"); > > + goto out; > > + } > > + > > + /* go through the list */ > > + for (sig_data = siglist->sig_data_list; sig_data; > > + sig_data = sig_data->next) { > > +#ifdef DEBUG > > + debug("Msg digest in database:\n"); > > + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1, > > + sig_data->data, sig_data->size, false); > > +#endif > > + if ((sig_data->size == size) && > > + !memcmp(sig_data->data, hash, size)) { > > + verified = true; > > + free(hash); > > + goto out; > > + } > > + } > > + free(hash); > > + goto out; > > + } > > + > > + debug("%s: signed image\n", __func__); > > + if (guidcmp(&siglist->sig_type, &efi_guid_cert_x509)) { > > + debug("Signature type is not supported: %pUl\n", > > + &siglist->sig_type); > > + goto out; > > + } > > + > > + /* go through the list */ > > + for (sig_data = siglist->sig_data_list; sig_data; > > + sig_data = sig_data->next) { > > + /* TODO: support owner check based on policy */ > > + > > + cert = x509_cert_parse(sig_data->data, sig_data->size); > > + if (IS_ERR(cert)) { > > + debug("Parsing x509 certificate failed\n"); > > + goto out; > > + } > > + > > + verified = efi_signature_verify(regs, msg, signed_info, cert); > > + > > + if (verified) { > > + if (valid_cert) > > + *valid_cert = cert; > > + else > > + x509_free_certificate(cert); > > + break; > > + } > > + x509_free_certificate(cert); > > + } > > + > > +out: > > + debug("%s: Exit, verified: %d\n", __func__, verified); > > + return verified; > > +} > > + > > +/** > > + * efi_signature_verify_with_sigdb - verify a signature with db > > + * @regs: List of regions to be authenticated > > + * @msg: Signature > > + * @db: Signature database for trusted certificates > > + * @cert: x509 certificate that verifies this signature > > + * > > + * Signature pointed to by @msg against image pointed to by @regs > > + * is verified by signature database pointed to by @db. > > + * > > + * Return: true if signature is verified, false if not > > + */ > > +bool efi_signature_verify_with_sigdb(struct efi_image_regions *regs, > > + struct pkcs7_message *msg, > > + struct efi_signature_store *db, > > + struct x509_certificate **cert) > > +{ > > + struct pkcs7_signed_info *info; > > + struct efi_signature_store *siglist; > > + bool verified = false; > > + > > + debug("%s: Enter, %p, %p, %p, %p\n", __func__, regs, msg, db, cert); > > + > > + if (!db) > > + goto out; > > + > > + if (!db->sig_data_list) > > + goto out; > > + > > + /* for unsigned image */ > > + if (!msg) { > > + debug("%s: Verify unsigned image with db\n", __func__); > > + for (siglist = db; siglist; siglist = siglist->next) > > + if (efi_signature_verify_with_list(regs, NULL, NULL, > > + siglist, cert)) { > > + verified = true; > > + goto out; > > + } > > + > > + goto out; > > + } > > + > > + /* for signed image or variable */ > > + debug("%s: Verify signed image with db\n", __func__); > > + for (info = msg->signed_infos; info; info = info->next) { > > + debug("Signed Info: digest algo: %s, pkey algo: %s\n", > > + info->sig->hash_algo, info->sig->pkey_algo); > > + > > + for (siglist = db; siglist; siglist = siglist->next) { > > + if (efi_signature_verify_with_list(regs, msg, info, > > + siglist, cert)) { > > + verified = true; > > + goto out; > > + } > > + } > > + } > > + > > +out: > > + debug("%s: Exit, verified: %d\n", __func__, verified); > > + return verified; > > +} > > + > > +/** > > + * efi_search_siglist - search signature list for a certificate > > + * @cert: x509 certificate > > + * @siglist: Signature list > > + * @revoc_time: Pointer to buffer for revocation time > > + * > > + * Search signature list pointed to by @siglist and find a certificate > > + * pointed to by @cert. > > + * If found, revocation time that is specified in signature database is > > + * returned in @revoc_time. > > + * > > + * Return: true if certificate is found, false if not > > + */ > > +static bool efi_search_siglist(struct x509_certificate *cert, > > + struct efi_signature_store *siglist, > > + time64_t *revoc_time) > > +{ > > + struct image_region reg[1]; > > + void *hash = NULL, *msg = NULL; > > + struct efi_sig_data *sig_data; > > + bool found = false; > > + > > + /* can be null */ > > + if (!siglist->sig_data_list) > > + return false; > > + > > + if (guidcmp(&siglist->sig_type, &efi_guid_cert_x509_sha256)) { > > + /* TODO: other hash algos */ > > + debug("Certificate's digest type is not supported: %pUl\n", > > + &siglist->sig_type); > > + goto out; > > + } > > + > > + /* calculate hash of TBSCertificate */ > > + msg = calloc(1, SHA256_SUM_LEN); > > + if (!msg) { > > + debug("Out of memory\n"); > > + goto out; > > + } > > + > > + hash = calloc(1, SHA256_SUM_LEN); > > + if (!hash) { > > + debug("Out of memory\n"); > > + goto out; > > + } > > + > > + reg[0].data = cert->tbs; > > + reg[0].size = cert->tbs_size; > > + hash_calculate("sha256", reg, 1, msg); > > + > > + /* go through signature list */ > > + for (sig_data = siglist->sig_data_list; sig_data; > > + sig_data = sig_data->next) { > > + /* > > + * struct efi_cert_x509_sha256 { > > + * u8 tbs_hash[256/8]; > > + * time64_t revocation_time; > > + * }; > > + */ > > + if ((sig_data->size == SHA256_SUM_LEN) && > > + !memcmp(sig_data->data, hash, SHA256_SUM_LEN)) { > > + memcpy(revoc_time, sig_data->data + SHA256_SUM_LEN, > > + sizeof(*revoc_time)); > > + found = true; > > + goto out; > > + } > > + } > > + > > +out: > > + free(hash); > > + free(msg); > > + > > + return found; > > +} > > + > > +/** > > + * efi_signature_verify_cert - verify a certificate with dbx > > + * @cert: x509 certificate > > + * @dbx: Signature database > > + * > > + * Search signature database pointed to by @dbx and find a certificate > > + * pointed to by @cert. > > + * This function is expected to be used against "dbx". > > + * > > + * Return: true if a certificate is not rejected, false otherwise. > > + */ > > +bool efi_signature_verify_cert(struct x509_certificate *cert, > > + struct efi_signature_store *dbx) > > +{ > > + struct efi_signature_store *siglist; > > + time64_t revoc_time; > > + bool found = false; > > + > > + debug("%s: Enter, %p, %p\n", __func__, dbx, cert); > > + > > + if (!cert) > > + return false; > > + > > + for (siglist = dbx; siglist; siglist = siglist->next) { > > + if (efi_search_siglist(cert, siglist, &revoc_time)) { > > + /* TODO */ > > + /* compare signing time with revocation time */ > > + > > + found = true; > > + break; > > + } > > + } > > + > > + debug("%s: Exit, verified: %d\n", __func__, !found); > > + return !found; > > +} > > + > > +/** > > + * efi_signature_verify_signers - verify signers' certificates with dbx > > + * @msg: Signature > > + * @dbx: Signature database > > + * > > + * Determine if any of signers' certificates in @msg may be verified > > + * by any of certificates in signature database pointed to by @dbx. > > + * This function is expected to be used against "dbx". > > + * > > + * Return: true if none of certificates is rejected, false otherwise. > > + */ > > +bool efi_signature_verify_signers(struct pkcs7_message *msg, > > + struct efi_signature_store *dbx) > > +{ > > + struct pkcs7_signed_info *info; > > + bool found = false; > > + > > + debug("%s: Enter, %p, %p\n", __func__, msg, dbx); > > + > > + if (!msg) > > + goto out; > > + > > + for (info = msg->signed_infos; info; info = info->next) { > > + if (info->signer && > > + !efi_signature_verify_cert(info->signer, dbx)) { > > + found = true; > > + goto out; > > + } > > + } > > +out: > > + debug("%s: Exit, verified: %d\n", __func__, !found); > > + return !found; > > +} > > + > > +/** > > + * efi_image_region_add - add an entry of region > > + * @regs: Pointer to array of regions > > + * @start: Start address of region > > + * @end: End address of region > > + * @nocheck: flag against overlapped regions > > + * > > + * Take one entry of region [@start, @end] and append it to the list > > + * pointed to by @regs. If @nocheck is false, overlapping among entries > > + * will be checked first. > > + * > > + * Return: 0 on success, status code (negative) on error > > + */ > > +efi_status_t efi_image_region_add(struct efi_image_regions *regs, > > + const void *start, const void *end, > > + int nocheck) > > +{ > > + struct image_region *reg; > > + int i, j; > > + > > + if (regs->num >= regs->max) { > > + debug("%s: no more room for regions\n", __func__); > > + return EFI_OUT_OF_RESOURCES; > > + } > > + > > + if (end < start) > > + return EFI_INVALID_PARAMETER; > > + > > + for (i = 0; i < regs->num; i++) { > > + reg = ®s->reg[i]; > > + if (nocheck) > > + continue; > > + > > + if (start > reg->data + reg->size) > > + continue; > > + > > + if ((start >= reg->data && start < reg->data + reg->size) || > > + (end > reg->data && end < reg->data + reg->size)) { > > + debug("%s: new region already part of another\n", > > + __func__); > > + return EFI_INVALID_PARAMETER; > > + } > > + > > + if (start < reg->data && end < reg->data + reg->size) { > > + for (j = regs->num - 1; j >= i; j--) > > + memcpy(®s->reg[j], ®s->reg[j + 1], > > + sizeof(*reg)); > > + break; > > + } > > + } > > + > > + reg = ®s->reg[i]; > > + reg->data = start; > > + reg->size = end - start; > > + regs->num++; > > + > > + return EFI_SUCCESS; > > +} > > +#endif /* CONFIG_EFI_SECURE_BOOT */ > > >
Heinrich, On Fri, Apr 17, 2020 at 08:16:06PM +0200, Heinrich Schuchardt wrote: > On 4/14/20 4:51 AM, AKASHI Takahiro wrote: > > In this commit, implemented are a couple of helper functions which will be > > used to materialize variable authentication as well as image authentication > > in later patches. > > > > Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org> > > --- > > include/efi_api.h | 87 +++++ > > include/efi_loader.h | 72 ++++ > > lib/efi_loader/Makefile | 1 + > > lib/efi_loader/efi_signature.c | 583 +++++++++++++++++++++++++++++++++ > > 4 files changed, 743 insertions(+) > > create mode 100644 lib/efi_loader/efi_signature.c > > > > diff --git a/include/efi_api.h b/include/efi_api.h > > index 1c40ffc4f56c..77d6bf2660b9 100644 > > --- a/include/efi_api.h > > +++ b/include/efi_api.h > > @@ -18,6 +18,7 @@ > > > > #include <efi.h> > > #include <charset.h> > > +#include <pe.h> > > > > #ifdef CONFIG_EFI_LOADER > > #include <asm/setjmp.h> > > @@ -329,6 +330,10 @@ struct efi_runtime_services { > > EFI_GUID(0x8be4df61, 0x93ca, 0x11d2, 0xaa, 0x0d, \ > > 0x00, 0xe0, 0x98, 0x03, 0x2b, 0x8c) > > > > +#define EFI_IMAGE_SECURITY_DATABASE_GUID \ > > + EFI_GUID(0xd719b2cb, 0x3d3a, 0x4596, 0xa3, 0xbc, \ > > + 0xda, 0xd0, 0x0e, 0x67, 0x65, 0x6f) > > + > > #define EFI_FDT_GUID \ > > EFI_GUID(0xb1b621d5, 0xf19c, 0x41a5, \ > > 0x83, 0x0b, 0xd9, 0x15, 0x2c, 0x69, 0xaa, 0xe0) > > @@ -1682,4 +1687,86 @@ struct efi_load_file_protocol { > > #define LAST_ATTEMPT_STATUS_ERROR_UNSUCCESSFUL_VENDOR_RANGE_MIN 0x00001000 > > #define LAST_ATTEMPT_STATUS_ERROR_UNSUCCESSFUL_VENDOR_RANGE_MAX 0x00004000 > > > > +/* Certificate types in signature database */ > > +#define EFI_CERT_SHA256_GUID \ > > + EFI_GUID(0xc1c41626, 0x504c, 0x4092, 0xac, 0xa9, \ > > + 0x41, 0xf9, 0x36, 0x93, 0x43, 0x28) > > +#define EFI_CERT_RSA2048_GUID \ > > + EFI_GUID(0x3c5766e8, 0x269c, 0x4e34, 0xaa, 0x14, \ > > + 0xed, 0x77, 0x6e, 0x85, 0xb3, 0xb6) > > +#define EFI_CERT_X509_GUID \ > > + EFI_GUID(0xa5c059a1, 0x94e4, 0x4aa7, 0x87, 0xb5, \ > > + 0xab, 0x15, 0x5c, 0x2b, 0xf0, 0x72) > > +#define EFI_CERT_X509_SHA256_GUID \ > > + EFI_GUID(0x3bd2a492, 0x96c0, 0x4079, 0xb4, 0x20, \ > > + 0xfc, 0xf9, 0x8e, 0xf1, 0x03, 0xed) > > +#define EFI_CERT_TYPE_PKCS7_GUID \ > > + EFI_GUID(0x4aafd29d, 0x68df, 0x49ee, 0x8a, 0xa9, \ > > + 0x34, 0x7d, 0x37, 0x56, 0x65, 0xa7) > > + > > +/** > > + * win_certificate_uefi_guid - A certificate that encapsulates > > + * a GUID-specific signature > > + * > > + * @hdr: Windows certificate header > > + * @cert_type: Certificate type > > + * @cert_data: Certificate data > > + */ > > +struct win_certificate_uefi_guid { > > + WIN_CERTIFICATE hdr; > > + efi_guid_t cert_type; > > + u8 cert_data[]; > > +} __attribute__((__packed__)); > > + > > +/** > > + * efi_variable_authentication_2 - A time-based authentication method > > + * descriptor > > + * > > + * This structure describes an authentication information for > > + * a variable with EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS > > + * and should be included as part of a variable's value. > > + * Only EFI_CERT_TYPE_PKCS7_GUID is accepted. > > + * > > + * @time_stamp: Descriptor's time stamp > > + * @auth_info: Authentication info > > + */ > > +struct efi_variable_authentication_2 { > > + struct efi_time time_stamp; > > + struct win_certificate_uefi_guid auth_info; > > +} __attribute__((__packed__)); > > + > > +/** > > + * efi_signature_data - A format of signature > > + * > > + * This structure describes a single signature in signature database. > > + * > > + * @signature_owner: Signature owner > > + * @signature_data: Signature data > > + */ > > +struct efi_signature_data { > > + efi_guid_t signature_owner; > > + u8 signature_data[]; > > +} __attribute__((__packed__)); > > + > > +/** > > + * efi_signature_list - A format of signature database > > + * > > + * This structure describes a list of signatures with the same type. > > + * An authenticated variable's value is a concatenation of one or more > > + * efi_signature_list's. > > + * > > + * @signature_type: Signature type > > + * @signature_list_size: Size of signature list > > + * @signature_header_size: Size of signature header > > + * @signature_size: Size of signature > > + */ > > +struct efi_signature_list { > > + efi_guid_t signature_type; > > + u32 signature_list_size; > > + u32 signature_header_size; > > + u32 signature_size; > > +/* u8 signature_header[signature_header_size]; */ > > +/* struct efi_signature_data signatures[...][signature_size]; */ > > +} __attribute__((__packed__)); > > + > > #endif > > diff --git a/include/efi_loader.h b/include/efi_loader.h > > index 3f2792892f34..8cf85d2fb7e2 100644 > > --- a/include/efi_loader.h > > +++ b/include/efi_loader.h > > @@ -26,6 +26,7 @@ static inline void *guidcpy(void *dst, const void *src) > > #if CONFIG_IS_ENABLED(EFI_LOADER) > > > > #include <linux/list.h> > > +#include <linux/oid_registry.h> > > > > /* Maximum number of configuration tables */ > > #define EFI_MAX_CONFIGURATION_TABLES 16 > > @@ -178,6 +179,11 @@ extern const efi_guid_t efi_guid_hii_config_routing_protocol; > > extern const efi_guid_t efi_guid_hii_config_access_protocol; > > extern const efi_guid_t efi_guid_hii_database_protocol; > > extern const efi_guid_t efi_guid_hii_string_protocol; > > +/* GUIDs for authentication */ > > +extern const efi_guid_t efi_guid_image_security_database; > > +extern const efi_guid_t efi_guid_sha256; > > +extern const efi_guid_t efi_guid_cert_x509; > > +extern const efi_guid_t efi_guid_cert_x509_sha256; > > > > /* GUID of RNG protocol */ > > extern const efi_guid_t efi_guid_rng_protocol; > > @@ -680,6 +686,72 @@ void efi_deserialize_load_option(struct efi_load_option *lo, u8 *data); > > unsigned long efi_serialize_load_option(struct efi_load_option *lo, u8 **data); > > efi_status_t efi_bootmgr_load(efi_handle_t *handle); > > > > +#ifdef CONFIG_EFI_SECURE_BOOT > > +#include <image.h> > > + > > +/** > > + * efi_image_regions - A list of memory regions > > + * > > + * @max: Maximum number of regions > > + * @num: Number of regions > > + * @reg: array of regions > > + */ > > +struct efi_image_regions { > > + int max; > > + int num; > > + struct image_region reg[]; > > +}; > > + > > +/** > > + * efi_sig_data - A decoded data of struct efi_signature_data > > + * > > + * This structure represents an internal form of signature in > > + * signature database. A listed list may represent a signature list. > > + * > > + * @next: Pointer to next entry > > + * @onwer: Signature owner > > + * @data: Pointer to signature data > > + * @size: Size of signature data > > + */ > > +struct efi_sig_data { > > + struct efi_sig_data *next; > > + efi_guid_t owner; > > + void *data; > > + size_t size; > > +}; > > + > > +/** > > + * efi_signature_store - A decoded data of signature database > > + * > > + * This structure represents an internal form of signature database. > > + * > > + * @next: Pointer to next entry > > + * @sig_type: Signature type > > + * @sig_data_list: Pointer to signature list > > + */ > > +struct efi_signature_store { > > + struct efi_signature_store *next; > > + efi_guid_t sig_type; > > + struct efi_sig_data *sig_data_list; > > +}; > > + > > +struct x509_certificate; > > +struct pkcs7_message; > > + > > +bool efi_signature_verify_cert(struct x509_certificate *cert, > > + struct efi_signature_store *dbx); > > +bool efi_signature_verify_signers(struct pkcs7_message *msg, > > + struct efi_signature_store *dbx); > > +bool efi_signature_verify_with_sigdb(struct efi_image_regions *regs, > > + struct pkcs7_message *msg, > > + struct efi_signature_store *db, > > + struct x509_certificate **cert); > > + > > +efi_status_t efi_image_region_add(struct efi_image_regions *regs, > > + const void *start, const void *end, > > + int nocheck); > > +#endif /* CONFIG_EFI_SECURE_BOOT */ > > + > > #else /* CONFIG_IS_ENABLED(EFI_LOADER) */ > > > > /* Without CONFIG_EFI_LOADER we don't have a runtime section, stub it out */ > > diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile > > index 9b3b70447336..eff3c25ec301 100644 > > --- a/lib/efi_loader/Makefile > > +++ b/lib/efi_loader/Makefile > > @@ -44,3 +44,4 @@ obj-$(CONFIG_GENERATE_ACPI_TABLE) += efi_acpi.o > > obj-$(CONFIG_GENERATE_SMBIOS_TABLE) += efi_smbios.o > > obj-$(CONFIG_EFI_RNG_PROTOCOL) += efi_rng.o > > obj-$(CONFIG_EFI_LOAD_FILE2_INITRD) += efi_load_initrd.o > > +obj-y += efi_signature.o > > diff --git a/lib/efi_loader/efi_signature.c b/lib/efi_loader/efi_signature.c > > new file mode 100644 > > index 000000000000..23dac94c0593 > > --- /dev/null > > +++ b/lib/efi_loader/efi_signature.c > > @@ -0,0 +1,583 @@ > > +// SPDX-License-Identifier: GPL-2.0+ > > +/* > > + * Copyright (c) 2018 Patrick Wildt <patrick at blueri.se> > > + * Copyright (c) 2019 Linaro Limited, Author: AKASHI Takahiro > > + */ > > + > > +#include <common.h> > > +#include <charset.h> > > +#include <efi_loader.h> > > +#include <image.h> > > +#include <hexdump.h> > > +#include <malloc.h> > > +#include <pe.h> > > +#include <linux/compat.h> > > +#include <linux/oid_registry.h> > > +#include <u-boot/rsa.h> > > +#include <u-boot/sha256.h> > > +/* > > + * avoid duplicated inclusion: > > + * #include "../lib/crypto/x509_parser.h" > > + */ > > +#include "../lib/crypto/pkcs7_parser.h" > > + > > +const efi_guid_t efi_guid_image_security_database = > > + EFI_IMAGE_SECURITY_DATABASE_GUID; > > +const efi_guid_t efi_guid_sha256 = EFI_CERT_SHA256_GUID; > > +const efi_guid_t efi_guid_cert_rsa2048 = EFI_CERT_RSA2048_GUID; > > +const efi_guid_t efi_guid_cert_x509 = EFI_CERT_X509_GUID; > > +const efi_guid_t efi_guid_cert_x509_sha256 = EFI_CERT_X509_SHA256_GUID; > > + > > +#ifdef CONFIG_EFI_SECURE_BOOT > > + > > +/** > > + * efi_hash_regions - calculate a hash value > > + * @regs: List of regions > > + * @hash: Pointer to a pointer to buffer holding a hash value > > + * @size: Size of buffer to be returned > > + * > > + * Calculate a sha256 value of @regs and return a value in @hash. > > + * > > + * Return: true on success, false on error > > + */ > > +static bool efi_hash_regions(struct efi_image_regions *regs, void **hash, > > + size_t *size) > > +{ > > + *size = 0; > > + *hash = calloc(1, SHA256_SUM_LEN); > > + if (!*hash) { > > + debug("Out of memory\n"); > > + return false; > > + } > > + *size = SHA256_SUM_LEN; > > + > > + hash_calculate("sha256", regs->reg, regs->num, *hash); > > +#ifdef DEBUG > > + debug("hash calculated:\n"); > > + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1, > > + *hash, SHA256_SUM_LEN, false); > > +#endif > > + > > + return true; > > +} > > + > > +/** > > + * efi_hash_msg_content - calculate a hash value of contentInfo > > + * @msg: Signature > > + * @hash: Pointer to a pointer to buffer holding a hash value > > + * @size: Size of buffer to be returned > > + * > > + * Calculate a sha256 value of contentInfo in @msg and return a value in @hash. > > + * > > + * Return: true on success, false on error > > + */ > > +static bool efi_hash_msg_content(struct pkcs7_message *msg, void **hash, > > + size_t *size) > > +{ > > + struct image_region regtmp; > > + > > + *size = 0; > > + *hash = calloc(1, SHA256_SUM_LEN); > > + if (!*hash) { > > + debug("Out of memory\n"); > > + free(msg); > > + return false; > > + } > > + *size = SHA256_SUM_LEN; > > + > > + regtmp.data = msg->data; > > + regtmp.size = msg->data_len; > > + > > + hash_calculate("sha256", ®tmp, 1, *hash); > > +#ifdef DEBUG > > + debug("hash calculated based on contentInfo:\n"); > > + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1, > > + *hash, SHA256_SUM_LEN, false); > > +#endif > > + > > + return true; > > +} > > + > > +/** > > + * efi_signature_verify - verify a signature with a certificate > > + * @regs: List of regions to be authenticated > > + * @signed_info: Pointer to PKCS7's signed_info > > + * @cert: x509 certificate > > + * > > + * Signature pointed to by @signed_info against image pointed to by @regs > > + * is verified by a certificate pointed to by @cert. > > + * @signed_info holds a signature, including a message digest which is to be > > + * compared with a hash value calculated from @regs. > > + * > > + * Return: true if signature is verified, false if not > > + */ > > +static bool efi_signature_verify(struct efi_image_regions *regs, > > + struct pkcs7_message *msg, > > + struct pkcs7_signed_info *ps_info, > > + struct x509_certificate *cert) > > +{ > > + struct image_sign_info info; > > + struct image_region regtmp[2]; > > + void *hash; > > + size_t size; > > + char c; > > + bool verified; > > + > > + debug("%s: Enter, %p, %p, %p(issuer: %s, subject: %s)\n", __func__, > > + regs, ps_info, cert, cert->issuer, cert->subject); > > + > > + verified = false; > > + > > + memset(&info, '\0', sizeof(info)); > > + info.padding = image_get_padding_algo("pkcs-1.5"); > > + /* > > + * Note: image_get_[checksum|crypto]_algo takes an string > > + * argument like "<checksum>,<crypto>" > > + * TODO: support other hash algorithms > > + */ > > + if (!strcmp(ps_info->sig->hash_algo, "sha1")) { > > There is a call > efi_signature_verify_with_list(regs, NULL, NULL, siglist, cert) > So ps_info may be NULL efi_signature_verify() is called only if signed_info is not NULL. > > + info.checksum = image_get_checksum_algo("sha1,rsa2048"); > > + info.name = "sha1,rsa2048"; > > + } else if (!strcmp(ps_info->sig->hash_algo, "sha256")) { > > + info.checksum = image_get_checksum_algo("sha256,rsa2048"); > > + info.name = "sha256,rsa2048"; > > + } else { > > + debug("unknown msg digest algo: %s\n", ps_info->sig->hash_algo); > > + goto out; > > + } > > + info.crypto = image_get_crypto_algo(info.name); > > + > > + info.key = cert->pub->key; > > + info.keylen = cert->pub->keylen; > > + > > + /* verify signature */ > > + debug("%s: crypto: %s, signature len:%x\n", __func__, > > + info.name, ps_info->sig->s_size); > > + if (ps_info->aa_set & (1UL << sinfo_has_message_digest)) { > > There is a call > efi_signature_verify_with_list(regs, NULL, NULL, siglist, cert) > So ps_info may be NULL ditto > > + debug("%s: RSA verify authentication attribute\n", __func__); > > + /* > > + * NOTE: This path will be executed only for > > + * PE image authentication > > + */ > > + > > + /* check if hash matches digest first */ > > + debug("checking msg digest first, len:0x%x\n", > > + ps_info->msgdigest_len); > > + > > +#ifdef DEBUG > > + debug("hash in database:\n"); > > + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1, > > + ps_info->msgdigest, ps_info->msgdigest_len, > > + false); > > +#endif > > + /* against contentInfo first */ > > + if ((msg->data && efi_hash_msg_content(msg, &hash, &size)) || > > + /* for signed image */ > > There is a call > efi_signature_verify_with_list(regs, NULL, NULL, siglist, cert) > So msg may be NULL. msg is used only if signed_info is also provided. Please note that <msg,psinfo> == <NULL,NULL> case means that the image is not signed. That is why the code causes no runtime memory fault. > Either avoid the call will NULL or check the parameters before > dereferencing. > > Please, provide a follow up patch. Therefore I don't think that any fix will be necessary. Thanks, -Takahiro Akashi > I used cppcheck to identify this problem. > > Best regards > > Heinrich > > > + efi_hash_regions(regs, &hash, &size)) { > > + /* for authenticated variable */ > > + if (ps_info->msgdigest_len != size || > > + memcmp(hash, ps_info->msgdigest, size)) { > > + debug("Digest doesn't match\n"); > > + free(hash); > > + goto out; > > + } > > + > > + free(hash); > > + } else { > > + debug("Digesting image failed\n"); > > + goto out; > > + } > > + > > + /* against digest */ > > + c = 0x31; > > + regtmp[0].data = &c; > > + regtmp[0].size = 1; > > + regtmp[1].data = ps_info->authattrs; > > + regtmp[1].size = ps_info->authattrs_len; > > + > > + if (!rsa_verify(&info, regtmp, 2, > > + ps_info->sig->s, ps_info->sig->s_size)) > > + verified = true; > > + } else { > > + debug("%s: RSA verify content data\n", __func__); > > + /* against all data */ > > + if (!rsa_verify(&info, regs->reg, regs->num, > > + ps_info->sig->s, ps_info->sig->s_size)) > > + verified = true; > > + } > > + > > +out: > > + debug("%s: Exit, verified: %d\n", __func__, verified); > > + return verified; > > +} > > + > > +/** > > + * efi_signature_verify_with_list - verify a signature with signature list > > + * @regs: List of regions to be authenticated > > + * @msg: Signature > > + * @signed_info: Pointer to PKCS7's signed_info > > + * @siglist: Signature list for certificates > > + * @valid_cert: x509 certificate that verifies this signature > > + * > > + * Signature pointed to by @signed_info against image pointed to by @regs > > + * is verified by signature list pointed to by @siglist. > > + * Signature database is a simple concatenation of one or more > > + * signature list(s). > > + * > > + * Return: true if signature is verified, false if not > > + */ > > +static > > +bool efi_signature_verify_with_list(struct efi_image_regions *regs, > > + struct pkcs7_message *msg, > > + struct pkcs7_signed_info *signed_info, > > + struct efi_signature_store *siglist, > > + struct x509_certificate **valid_cert) > > +{ > > + struct x509_certificate *cert; > > + struct efi_sig_data *sig_data; > > + bool verified = false; > > + > > + debug("%s: Enter, %p, %p, %p, %p\n", __func__, > > + regs, signed_info, siglist, valid_cert); > > + > > + if (!signed_info) { > > + void *hash; > > + size_t size; > > + > > + debug("%s: unsigned image\n", __func__); > > + /* > > + * verify based on calculated hash value > > + * TODO: support other hash algorithms > > + */ > > + if (guidcmp(&siglist->sig_type, &efi_guid_sha256)) { > > + debug("Digest algorithm is not supported: %pUl\n", > > + &siglist->sig_type); > > + goto out; > > + } > > + > > + if (!efi_hash_regions(regs, &hash, &size)) { > > + debug("Digesting unsigned image failed\n"); > > + goto out; > > + } > > + > > + /* go through the list */ > > + for (sig_data = siglist->sig_data_list; sig_data; > > + sig_data = sig_data->next) { > > +#ifdef DEBUG > > + debug("Msg digest in database:\n"); > > + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1, > > + sig_data->data, sig_data->size, false); > > +#endif > > + if ((sig_data->size == size) && > > + !memcmp(sig_data->data, hash, size)) { > > + verified = true; > > + free(hash); > > + goto out; > > + } > > + } > > + free(hash); > > + goto out; > > + } > > + > > + debug("%s: signed image\n", __func__); > > + if (guidcmp(&siglist->sig_type, &efi_guid_cert_x509)) { > > + debug("Signature type is not supported: %pUl\n", > > + &siglist->sig_type); > > + goto out; > > + } > > + > > + /* go through the list */ > > + for (sig_data = siglist->sig_data_list; sig_data; > > + sig_data = sig_data->next) { > > + /* TODO: support owner check based on policy */ > > + > > + cert = x509_cert_parse(sig_data->data, sig_data->size); > > + if (IS_ERR(cert)) { > > + debug("Parsing x509 certificate failed\n"); > > + goto out; > > + } > > + > > + verified = efi_signature_verify(regs, msg, signed_info, cert); > > + > > + if (verified) { > > + if (valid_cert) > > + *valid_cert = cert; > > + else > > + x509_free_certificate(cert); > > + break; > > + } > > + x509_free_certificate(cert); > > + } > > + > > +out: > > + debug("%s: Exit, verified: %d\n", __func__, verified); > > + return verified; > > +} > > + > > +/** > > + * efi_signature_verify_with_sigdb - verify a signature with db > > + * @regs: List of regions to be authenticated > > + * @msg: Signature > > + * @db: Signature database for trusted certificates > > + * @cert: x509 certificate that verifies this signature > > + * > > + * Signature pointed to by @msg against image pointed to by @regs > > + * is verified by signature database pointed to by @db. > > + * > > + * Return: true if signature is verified, false if not > > + */ > > +bool efi_signature_verify_with_sigdb(struct efi_image_regions *regs, > > + struct pkcs7_message *msg, > > + struct efi_signature_store *db, > > + struct x509_certificate **cert) > > +{ > > + struct pkcs7_signed_info *info; > > + struct efi_signature_store *siglist; > > + bool verified = false; > > + > > + debug("%s: Enter, %p, %p, %p, %p\n", __func__, regs, msg, db, cert); > > + > > + if (!db) > > + goto out; > > + > > + if (!db->sig_data_list) > > + goto out; > > + > > + /* for unsigned image */ > > + if (!msg) { > > + debug("%s: Verify unsigned image with db\n", __func__); > > + for (siglist = db; siglist; siglist = siglist->next) > > + if (efi_signature_verify_with_list(regs, NULL, NULL, > > + siglist, cert)) { > > + verified = true; > > + goto out; > > + } > > + > > + goto out; > > + } > > + > > + /* for signed image or variable */ > > + debug("%s: Verify signed image with db\n", __func__); > > + for (info = msg->signed_infos; info; info = info->next) { > > + debug("Signed Info: digest algo: %s, pkey algo: %s\n", > > + info->sig->hash_algo, info->sig->pkey_algo); > > + > > + for (siglist = db; siglist; siglist = siglist->next) { > > + if (efi_signature_verify_with_list(regs, msg, info, > > + siglist, cert)) { > > + verified = true; > > + goto out; > > + } > > + } > > + } > > + > > +out: > > + debug("%s: Exit, verified: %d\n", __func__, verified); > > + return verified; > > +} > > + > > +/** > > + * efi_search_siglist - search signature list for a certificate > > + * @cert: x509 certificate > > + * @siglist: Signature list > > + * @revoc_time: Pointer to buffer for revocation time > > + * > > + * Search signature list pointed to by @siglist and find a certificate > > + * pointed to by @cert. > > + * If found, revocation time that is specified in signature database is > > + * returned in @revoc_time. > > + * > > + * Return: true if certificate is found, false if not > > + */ > > +static bool efi_search_siglist(struct x509_certificate *cert, > > + struct efi_signature_store *siglist, > > + time64_t *revoc_time) > > +{ > > + struct image_region reg[1]; > > + void *hash = NULL, *msg = NULL; > > + struct efi_sig_data *sig_data; > > + bool found = false; > > + > > + /* can be null */ > > + if (!siglist->sig_data_list) > > + return false; > > + > > + if (guidcmp(&siglist->sig_type, &efi_guid_cert_x509_sha256)) { > > + /* TODO: other hash algos */ > > + debug("Certificate's digest type is not supported: %pUl\n", > > + &siglist->sig_type); > > + goto out; > > + } > > + > > + /* calculate hash of TBSCertificate */ > > + msg = calloc(1, SHA256_SUM_LEN); > > + if (!msg) { > > + debug("Out of memory\n"); > > + goto out; > > + } > > + > > + hash = calloc(1, SHA256_SUM_LEN); > > + if (!hash) { > > + debug("Out of memory\n"); > > + goto out; > > + } > > + > > + reg[0].data = cert->tbs; > > + reg[0].size = cert->tbs_size; > > + hash_calculate("sha256", reg, 1, msg); > > + > > + /* go through signature list */ > > + for (sig_data = siglist->sig_data_list; sig_data; > > + sig_data = sig_data->next) { > > + /* > > + * struct efi_cert_x509_sha256 { > > + * u8 tbs_hash[256/8]; > > + * time64_t revocation_time; > > + * }; > > + */ > > + if ((sig_data->size == SHA256_SUM_LEN) && > > + !memcmp(sig_data->data, hash, SHA256_SUM_LEN)) { > > + memcpy(revoc_time, sig_data->data + SHA256_SUM_LEN, > > + sizeof(*revoc_time)); > > + found = true; > > + goto out; > > + } > > + } > > + > > +out: > > + free(hash); > > + free(msg); > > + > > + return found; > > +} > > + > > +/** > > + * efi_signature_verify_cert - verify a certificate with dbx > > + * @cert: x509 certificate > > + * @dbx: Signature database > > + * > > + * Search signature database pointed to by @dbx and find a certificate > > + * pointed to by @cert. > > + * This function is expected to be used against "dbx". > > + * > > + * Return: true if a certificate is not rejected, false otherwise. > > + */ > > +bool efi_signature_verify_cert(struct x509_certificate *cert, > > + struct efi_signature_store *dbx) > > +{ > > + struct efi_signature_store *siglist; > > + time64_t revoc_time; > > + bool found = false; > > + > > + debug("%s: Enter, %p, %p\n", __func__, dbx, cert); > > + > > + if (!cert) > > + return false; > > + > > + for (siglist = dbx; siglist; siglist = siglist->next) { > > + if (efi_search_siglist(cert, siglist, &revoc_time)) { > > + /* TODO */ > > + /* compare signing time with revocation time */ > > + > > + found = true; > > + break; > > + } > > + } > > + > > + debug("%s: Exit, verified: %d\n", __func__, !found); > > + return !found; > > +} > > + > > +/** > > + * efi_signature_verify_signers - verify signers' certificates with dbx > > + * @msg: Signature > > + * @dbx: Signature database > > + * > > + * Determine if any of signers' certificates in @msg may be verified > > + * by any of certificates in signature database pointed to by @dbx. > > + * This function is expected to be used against "dbx". > > + * > > + * Return: true if none of certificates is rejected, false otherwise. > > + */ > > +bool efi_signature_verify_signers(struct pkcs7_message *msg, > > + struct efi_signature_store *dbx) > > +{ > > + struct pkcs7_signed_info *info; > > + bool found = false; > > + > > + debug("%s: Enter, %p, %p\n", __func__, msg, dbx); > > + > > + if (!msg) > > + goto out; > > + > > + for (info = msg->signed_infos; info; info = info->next) { > > + if (info->signer && > > + !efi_signature_verify_cert(info->signer, dbx)) { > > + found = true; > > + goto out; > > + } > > + } > > +out: > > + debug("%s: Exit, verified: %d\n", __func__, !found); > > + return !found; > > +} > > + > > +/** > > + * efi_image_region_add - add an entry of region > > + * @regs: Pointer to array of regions > > + * @start: Start address of region > > + * @end: End address of region > > + * @nocheck: flag against overlapped regions > > + * > > + * Take one entry of region [@start, @end] and append it to the list > > + * pointed to by @regs. If @nocheck is false, overlapping among entries > > + * will be checked first. > > + * > > + * Return: 0 on success, status code (negative) on error > > + */ > > +efi_status_t efi_image_region_add(struct efi_image_regions *regs, > > + const void *start, const void *end, > > + int nocheck) > > +{ > > + struct image_region *reg; > > + int i, j; > > + > > + if (regs->num >= regs->max) { > > + debug("%s: no more room for regions\n", __func__); > > + return EFI_OUT_OF_RESOURCES; > > + } > > + > > + if (end < start) > > + return EFI_INVALID_PARAMETER; > > + > > + for (i = 0; i < regs->num; i++) { > > + reg = ®s->reg[i]; > > + if (nocheck) > > + continue; > > + > > + if (start > reg->data + reg->size) > > + continue; > > + > > + if ((start >= reg->data && start < reg->data + reg->size) || > > + (end > reg->data && end < reg->data + reg->size)) { > > + debug("%s: new region already part of another\n", > > + __func__); > > + return EFI_INVALID_PARAMETER; > > + } > > + > > + if (start < reg->data && end < reg->data + reg->size) { > > + for (j = regs->num - 1; j >= i; j--) > > + memcpy(®s->reg[j], ®s->reg[j + 1], > > + sizeof(*reg)); > > + break; > > + } > > + } > > + > > + reg = ®s->reg[i]; > > + reg->data = start; > > + reg->size = end - start; > > + regs->num++; > > + > > + return EFI_SUCCESS; > > +} > > +#endif /* CONFIG_EFI_SECURE_BOOT */ > > >
diff --git a/include/efi_api.h b/include/efi_api.h index 1c40ffc4f56c..77d6bf2660b9 100644 --- a/include/efi_api.h +++ b/include/efi_api.h @@ -18,6 +18,7 @@ #include <efi.h> #include <charset.h> +#include <pe.h> #ifdef CONFIG_EFI_LOADER #include <asm/setjmp.h> @@ -329,6 +330,10 @@ struct efi_runtime_services { EFI_GUID(0x8be4df61, 0x93ca, 0x11d2, 0xaa, 0x0d, \ 0x00, 0xe0, 0x98, 0x03, 0x2b, 0x8c) +#define EFI_IMAGE_SECURITY_DATABASE_GUID \ + EFI_GUID(0xd719b2cb, 0x3d3a, 0x4596, 0xa3, 0xbc, \ + 0xda, 0xd0, 0x0e, 0x67, 0x65, 0x6f) + #define EFI_FDT_GUID \ EFI_GUID(0xb1b621d5, 0xf19c, 0x41a5, \ 0x83, 0x0b, 0xd9, 0x15, 0x2c, 0x69, 0xaa, 0xe0) @@ -1682,4 +1687,86 @@ struct efi_load_file_protocol { #define LAST_ATTEMPT_STATUS_ERROR_UNSUCCESSFUL_VENDOR_RANGE_MIN 0x00001000 #define LAST_ATTEMPT_STATUS_ERROR_UNSUCCESSFUL_VENDOR_RANGE_MAX 0x00004000 +/* Certificate types in signature database */ +#define EFI_CERT_SHA256_GUID \ + EFI_GUID(0xc1c41626, 0x504c, 0x4092, 0xac, 0xa9, \ + 0x41, 0xf9, 0x36, 0x93, 0x43, 0x28) +#define EFI_CERT_RSA2048_GUID \ + EFI_GUID(0x3c5766e8, 0x269c, 0x4e34, 0xaa, 0x14, \ + 0xed, 0x77, 0x6e, 0x85, 0xb3, 0xb6) +#define EFI_CERT_X509_GUID \ + EFI_GUID(0xa5c059a1, 0x94e4, 0x4aa7, 0x87, 0xb5, \ + 0xab, 0x15, 0x5c, 0x2b, 0xf0, 0x72) +#define EFI_CERT_X509_SHA256_GUID \ + EFI_GUID(0x3bd2a492, 0x96c0, 0x4079, 0xb4, 0x20, \ + 0xfc, 0xf9, 0x8e, 0xf1, 0x03, 0xed) +#define EFI_CERT_TYPE_PKCS7_GUID \ + EFI_GUID(0x4aafd29d, 0x68df, 0x49ee, 0x8a, 0xa9, \ + 0x34, 0x7d, 0x37, 0x56, 0x65, 0xa7) + +/** + * win_certificate_uefi_guid - A certificate that encapsulates + * a GUID-specific signature + * + * @hdr: Windows certificate header + * @cert_type: Certificate type + * @cert_data: Certificate data + */ +struct win_certificate_uefi_guid { + WIN_CERTIFICATE hdr; + efi_guid_t cert_type; + u8 cert_data[]; +} __attribute__((__packed__)); + +/** + * efi_variable_authentication_2 - A time-based authentication method + * descriptor + * + * This structure describes an authentication information for + * a variable with EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS + * and should be included as part of a variable's value. + * Only EFI_CERT_TYPE_PKCS7_GUID is accepted. + * + * @time_stamp: Descriptor's time stamp + * @auth_info: Authentication info + */ +struct efi_variable_authentication_2 { + struct efi_time time_stamp; + struct win_certificate_uefi_guid auth_info; +} __attribute__((__packed__)); + +/** + * efi_signature_data - A format of signature + * + * This structure describes a single signature in signature database. + * + * @signature_owner: Signature owner + * @signature_data: Signature data + */ +struct efi_signature_data { + efi_guid_t signature_owner; + u8 signature_data[]; +} __attribute__((__packed__)); + +/** + * efi_signature_list - A format of signature database + * + * This structure describes a list of signatures with the same type. + * An authenticated variable's value is a concatenation of one or more + * efi_signature_list's. + * + * @signature_type: Signature type + * @signature_list_size: Size of signature list + * @signature_header_size: Size of signature header + * @signature_size: Size of signature + */ +struct efi_signature_list { + efi_guid_t signature_type; + u32 signature_list_size; + u32 signature_header_size; + u32 signature_size; +/* u8 signature_header[signature_header_size]; */ +/* struct efi_signature_data signatures[...][signature_size]; */ +} __attribute__((__packed__)); + #endif diff --git a/include/efi_loader.h b/include/efi_loader.h index 3f2792892f34..8cf85d2fb7e2 100644 --- a/include/efi_loader.h +++ b/include/efi_loader.h @@ -26,6 +26,7 @@ static inline void *guidcpy(void *dst, const void *src) #if CONFIG_IS_ENABLED(EFI_LOADER) #include <linux/list.h> +#include <linux/oid_registry.h> /* Maximum number of configuration tables */ #define EFI_MAX_CONFIGURATION_TABLES 16 @@ -178,6 +179,11 @@ extern const efi_guid_t efi_guid_hii_config_routing_protocol; extern const efi_guid_t efi_guid_hii_config_access_protocol; extern const efi_guid_t efi_guid_hii_database_protocol; extern const efi_guid_t efi_guid_hii_string_protocol; +/* GUIDs for authentication */ +extern const efi_guid_t efi_guid_image_security_database; +extern const efi_guid_t efi_guid_sha256; +extern const efi_guid_t efi_guid_cert_x509; +extern const efi_guid_t efi_guid_cert_x509_sha256; /* GUID of RNG protocol */ extern const efi_guid_t efi_guid_rng_protocol; @@ -680,6 +686,72 @@ void efi_deserialize_load_option(struct efi_load_option *lo, u8 *data); unsigned long efi_serialize_load_option(struct efi_load_option *lo, u8 **data); efi_status_t efi_bootmgr_load(efi_handle_t *handle); +#ifdef CONFIG_EFI_SECURE_BOOT +#include <image.h> + +/** + * efi_image_regions - A list of memory regions + * + * @max: Maximum number of regions + * @num: Number of regions + * @reg: array of regions + */ +struct efi_image_regions { + int max; + int num; + struct image_region reg[]; +}; + +/** + * efi_sig_data - A decoded data of struct efi_signature_data + * + * This structure represents an internal form of signature in + * signature database. A listed list may represent a signature list. + * + * @next: Pointer to next entry + * @onwer: Signature owner + * @data: Pointer to signature data + * @size: Size of signature data + */ +struct efi_sig_data { + struct efi_sig_data *next; + efi_guid_t owner; + void *data; + size_t size; +}; + +/** + * efi_signature_store - A decoded data of signature database + * + * This structure represents an internal form of signature database. + * + * @next: Pointer to next entry + * @sig_type: Signature type + * @sig_data_list: Pointer to signature list + */ +struct efi_signature_store { + struct efi_signature_store *next; + efi_guid_t sig_type; + struct efi_sig_data *sig_data_list; +}; + +struct x509_certificate; +struct pkcs7_message; + +bool efi_signature_verify_cert(struct x509_certificate *cert, + struct efi_signature_store *dbx); +bool efi_signature_verify_signers(struct pkcs7_message *msg, + struct efi_signature_store *dbx); +bool efi_signature_verify_with_sigdb(struct efi_image_regions *regs, + struct pkcs7_message *msg, + struct efi_signature_store *db, + struct x509_certificate **cert); + +efi_status_t efi_image_region_add(struct efi_image_regions *regs, + const void *start, const void *end, + int nocheck); +#endif /* CONFIG_EFI_SECURE_BOOT */ + #else /* CONFIG_IS_ENABLED(EFI_LOADER) */ /* Without CONFIG_EFI_LOADER we don't have a runtime section, stub it out */ diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile index 9b3b70447336..eff3c25ec301 100644 --- a/lib/efi_loader/Makefile +++ b/lib/efi_loader/Makefile @@ -44,3 +44,4 @@ obj-$(CONFIG_GENERATE_ACPI_TABLE) += efi_acpi.o obj-$(CONFIG_GENERATE_SMBIOS_TABLE) += efi_smbios.o obj-$(CONFIG_EFI_RNG_PROTOCOL) += efi_rng.o obj-$(CONFIG_EFI_LOAD_FILE2_INITRD) += efi_load_initrd.o +obj-y += efi_signature.o diff --git a/lib/efi_loader/efi_signature.c b/lib/efi_loader/efi_signature.c new file mode 100644 index 000000000000..23dac94c0593 --- /dev/null +++ b/lib/efi_loader/efi_signature.c @@ -0,0 +1,583 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (c) 2018 Patrick Wildt <patrick at blueri.se> + * Copyright (c) 2019 Linaro Limited, Author: AKASHI Takahiro + */ + +#include <common.h> +#include <charset.h> +#include <efi_loader.h> +#include <image.h> +#include <hexdump.h> +#include <malloc.h> +#include <pe.h> +#include <linux/compat.h> +#include <linux/oid_registry.h> +#include <u-boot/rsa.h> +#include <u-boot/sha256.h> +/* + * avoid duplicated inclusion: + * #include "../lib/crypto/x509_parser.h" + */ +#include "../lib/crypto/pkcs7_parser.h" + +const efi_guid_t efi_guid_image_security_database = + EFI_IMAGE_SECURITY_DATABASE_GUID; +const efi_guid_t efi_guid_sha256 = EFI_CERT_SHA256_GUID; +const efi_guid_t efi_guid_cert_rsa2048 = EFI_CERT_RSA2048_GUID; +const efi_guid_t efi_guid_cert_x509 = EFI_CERT_X509_GUID; +const efi_guid_t efi_guid_cert_x509_sha256 = EFI_CERT_X509_SHA256_GUID; + +#ifdef CONFIG_EFI_SECURE_BOOT + +/** + * efi_hash_regions - calculate a hash value + * @regs: List of regions + * @hash: Pointer to a pointer to buffer holding a hash value + * @size: Size of buffer to be returned + * + * Calculate a sha256 value of @regs and return a value in @hash. + * + * Return: true on success, false on error + */ +static bool efi_hash_regions(struct efi_image_regions *regs, void **hash, + size_t *size) +{ + *size = 0; + *hash = calloc(1, SHA256_SUM_LEN); + if (!*hash) { + debug("Out of memory\n"); + return false; + } + *size = SHA256_SUM_LEN; + + hash_calculate("sha256", regs->reg, regs->num, *hash); +#ifdef DEBUG + debug("hash calculated:\n"); + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1, + *hash, SHA256_SUM_LEN, false); +#endif + + return true; +} + +/** + * efi_hash_msg_content - calculate a hash value of contentInfo + * @msg: Signature + * @hash: Pointer to a pointer to buffer holding a hash value + * @size: Size of buffer to be returned + * + * Calculate a sha256 value of contentInfo in @msg and return a value in @hash. + * + * Return: true on success, false on error + */ +static bool efi_hash_msg_content(struct pkcs7_message *msg, void **hash, + size_t *size) +{ + struct image_region regtmp; + + *size = 0; + *hash = calloc(1, SHA256_SUM_LEN); + if (!*hash) { + debug("Out of memory\n"); + free(msg); + return false; + } + *size = SHA256_SUM_LEN; + + regtmp.data = msg->data; + regtmp.size = msg->data_len; + + hash_calculate("sha256", ®tmp, 1, *hash); +#ifdef DEBUG + debug("hash calculated based on contentInfo:\n"); + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1, + *hash, SHA256_SUM_LEN, false); +#endif + + return true; +} + +/** + * efi_signature_verify - verify a signature with a certificate + * @regs: List of regions to be authenticated + * @signed_info: Pointer to PKCS7's signed_info + * @cert: x509 certificate + * + * Signature pointed to by @signed_info against image pointed to by @regs + * is verified by a certificate pointed to by @cert. + * @signed_info holds a signature, including a message digest which is to be + * compared with a hash value calculated from @regs. + * + * Return: true if signature is verified, false if not + */ +static bool efi_signature_verify(struct efi_image_regions *regs, + struct pkcs7_message *msg, + struct pkcs7_signed_info *ps_info, + struct x509_certificate *cert) +{ + struct image_sign_info info; + struct image_region regtmp[2]; + void *hash; + size_t size; + char c; + bool verified; + + debug("%s: Enter, %p, %p, %p(issuer: %s, subject: %s)\n", __func__, + regs, ps_info, cert, cert->issuer, cert->subject); + + verified = false; + + memset(&info, '\0', sizeof(info)); + info.padding = image_get_padding_algo("pkcs-1.5"); + /* + * Note: image_get_[checksum|crypto]_algo takes an string + * argument like "<checksum>,<crypto>" + * TODO: support other hash algorithms + */ + if (!strcmp(ps_info->sig->hash_algo, "sha1")) { + info.checksum = image_get_checksum_algo("sha1,rsa2048"); + info.name = "sha1,rsa2048"; + } else if (!strcmp(ps_info->sig->hash_algo, "sha256")) { + info.checksum = image_get_checksum_algo("sha256,rsa2048"); + info.name = "sha256,rsa2048"; + } else { + debug("unknown msg digest algo: %s\n", ps_info->sig->hash_algo); + goto out; + } + info.crypto = image_get_crypto_algo(info.name); + + info.key = cert->pub->key; + info.keylen = cert->pub->keylen; + + /* verify signature */ + debug("%s: crypto: %s, signature len:%x\n", __func__, + info.name, ps_info->sig->s_size); + if (ps_info->aa_set & (1UL << sinfo_has_message_digest)) { + debug("%s: RSA verify authentication attribute\n", __func__); + /* + * NOTE: This path will be executed only for + * PE image authentication + */ + + /* check if hash matches digest first */ + debug("checking msg digest first, len:0x%x\n", + ps_info->msgdigest_len); + +#ifdef DEBUG + debug("hash in database:\n"); + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1, + ps_info->msgdigest, ps_info->msgdigest_len, + false); +#endif + /* against contentInfo first */ + if ((msg->data && efi_hash_msg_content(msg, &hash, &size)) || + /* for signed image */ + efi_hash_regions(regs, &hash, &size)) { + /* for authenticated variable */ + if (ps_info->msgdigest_len != size || + memcmp(hash, ps_info->msgdigest, size)) { + debug("Digest doesn't match\n"); + free(hash); + goto out; + } + + free(hash); + } else { + debug("Digesting image failed\n"); + goto out; + } + + /* against digest */ + c = 0x31; + regtmp[0].data = &c; + regtmp[0].size = 1; + regtmp[1].data = ps_info->authattrs; + regtmp[1].size = ps_info->authattrs_len; + + if (!rsa_verify(&info, regtmp, 2, + ps_info->sig->s, ps_info->sig->s_size)) + verified = true; + } else { + debug("%s: RSA verify content data\n", __func__); + /* against all data */ + if (!rsa_verify(&info, regs->reg, regs->num, + ps_info->sig->s, ps_info->sig->s_size)) + verified = true; + } + +out: + debug("%s: Exit, verified: %d\n", __func__, verified); + return verified; +} + +/** + * efi_signature_verify_with_list - verify a signature with signature list + * @regs: List of regions to be authenticated + * @msg: Signature + * @signed_info: Pointer to PKCS7's signed_info + * @siglist: Signature list for certificates + * @valid_cert: x509 certificate that verifies this signature + * + * Signature pointed to by @signed_info against image pointed to by @regs + * is verified by signature list pointed to by @siglist. + * Signature database is a simple concatenation of one or more + * signature list(s). + * + * Return: true if signature is verified, false if not + */ +static +bool efi_signature_verify_with_list(struct efi_image_regions *regs, + struct pkcs7_message *msg, + struct pkcs7_signed_info *signed_info, + struct efi_signature_store *siglist, + struct x509_certificate **valid_cert) +{ + struct x509_certificate *cert; + struct efi_sig_data *sig_data; + bool verified = false; + + debug("%s: Enter, %p, %p, %p, %p\n", __func__, + regs, signed_info, siglist, valid_cert); + + if (!signed_info) { + void *hash; + size_t size; + + debug("%s: unsigned image\n", __func__); + /* + * verify based on calculated hash value + * TODO: support other hash algorithms + */ + if (guidcmp(&siglist->sig_type, &efi_guid_sha256)) { + debug("Digest algorithm is not supported: %pUl\n", + &siglist->sig_type); + goto out; + } + + if (!efi_hash_regions(regs, &hash, &size)) { + debug("Digesting unsigned image failed\n"); + goto out; + } + + /* go through the list */ + for (sig_data = siglist->sig_data_list; sig_data; + sig_data = sig_data->next) { +#ifdef DEBUG + debug("Msg digest in database:\n"); + print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1, + sig_data->data, sig_data->size, false); +#endif + if ((sig_data->size == size) && + !memcmp(sig_data->data, hash, size)) { + verified = true; + free(hash); + goto out; + } + } + free(hash); + goto out; + } + + debug("%s: signed image\n", __func__); + if (guidcmp(&siglist->sig_type, &efi_guid_cert_x509)) { + debug("Signature type is not supported: %pUl\n", + &siglist->sig_type); + goto out; + } + + /* go through the list */ + for (sig_data = siglist->sig_data_list; sig_data; + sig_data = sig_data->next) { + /* TODO: support owner check based on policy */ + + cert = x509_cert_parse(sig_data->data, sig_data->size); + if (IS_ERR(cert)) { + debug("Parsing x509 certificate failed\n"); + goto out; + } + + verified = efi_signature_verify(regs, msg, signed_info, cert); + + if (verified) { + if (valid_cert) + *valid_cert = cert; + else + x509_free_certificate(cert); + break; + } + x509_free_certificate(cert); + } + +out: + debug("%s: Exit, verified: %d\n", __func__, verified); + return verified; +} + +/** + * efi_signature_verify_with_sigdb - verify a signature with db + * @regs: List of regions to be authenticated + * @msg: Signature + * @db: Signature database for trusted certificates + * @cert: x509 certificate that verifies this signature + * + * Signature pointed to by @msg against image pointed to by @regs + * is verified by signature database pointed to by @db. + * + * Return: true if signature is verified, false if not + */ +bool efi_signature_verify_with_sigdb(struct efi_image_regions *regs, + struct pkcs7_message *msg, + struct efi_signature_store *db, + struct x509_certificate **cert) +{ + struct pkcs7_signed_info *info; + struct efi_signature_store *siglist; + bool verified = false; + + debug("%s: Enter, %p, %p, %p, %p\n", __func__, regs, msg, db, cert); + + if (!db) + goto out; + + if (!db->sig_data_list) + goto out; + + /* for unsigned image */ + if (!msg) { + debug("%s: Verify unsigned image with db\n", __func__); + for (siglist = db; siglist; siglist = siglist->next) + if (efi_signature_verify_with_list(regs, NULL, NULL, + siglist, cert)) { + verified = true; + goto out; + } + + goto out; + } + + /* for signed image or variable */ + debug("%s: Verify signed image with db\n", __func__); + for (info = msg->signed_infos; info; info = info->next) { + debug("Signed Info: digest algo: %s, pkey algo: %s\n", + info->sig->hash_algo, info->sig->pkey_algo); + + for (siglist = db; siglist; siglist = siglist->next) { + if (efi_signature_verify_with_list(regs, msg, info, + siglist, cert)) { + verified = true; + goto out; + } + } + } + +out: + debug("%s: Exit, verified: %d\n", __func__, verified); + return verified; +} + +/** + * efi_search_siglist - search signature list for a certificate + * @cert: x509 certificate + * @siglist: Signature list + * @revoc_time: Pointer to buffer for revocation time + * + * Search signature list pointed to by @siglist and find a certificate + * pointed to by @cert. + * If found, revocation time that is specified in signature database is + * returned in @revoc_time. + * + * Return: true if certificate is found, false if not + */ +static bool efi_search_siglist(struct x509_certificate *cert, + struct efi_signature_store *siglist, + time64_t *revoc_time) +{ + struct image_region reg[1]; + void *hash = NULL, *msg = NULL; + struct efi_sig_data *sig_data; + bool found = false; + + /* can be null */ + if (!siglist->sig_data_list) + return false; + + if (guidcmp(&siglist->sig_type, &efi_guid_cert_x509_sha256)) { + /* TODO: other hash algos */ + debug("Certificate's digest type is not supported: %pUl\n", + &siglist->sig_type); + goto out; + } + + /* calculate hash of TBSCertificate */ + msg = calloc(1, SHA256_SUM_LEN); + if (!msg) { + debug("Out of memory\n"); + goto out; + } + + hash = calloc(1, SHA256_SUM_LEN); + if (!hash) { + debug("Out of memory\n"); + goto out; + } + + reg[0].data = cert->tbs; + reg[0].size = cert->tbs_size; + hash_calculate("sha256", reg, 1, msg); + + /* go through signature list */ + for (sig_data = siglist->sig_data_list; sig_data; + sig_data = sig_data->next) { + /* + * struct efi_cert_x509_sha256 { + * u8 tbs_hash[256/8]; + * time64_t revocation_time; + * }; + */ + if ((sig_data->size == SHA256_SUM_LEN) && + !memcmp(sig_data->data, hash, SHA256_SUM_LEN)) { + memcpy(revoc_time, sig_data->data + SHA256_SUM_LEN, + sizeof(*revoc_time)); + found = true; + goto out; + } + } + +out: + free(hash); + free(msg); + + return found; +} + +/** + * efi_signature_verify_cert - verify a certificate with dbx + * @cert: x509 certificate + * @dbx: Signature database + * + * Search signature database pointed to by @dbx and find a certificate + * pointed to by @cert. + * This function is expected to be used against "dbx". + * + * Return: true if a certificate is not rejected, false otherwise. + */ +bool efi_signature_verify_cert(struct x509_certificate *cert, + struct efi_signature_store *dbx) +{ + struct efi_signature_store *siglist; + time64_t revoc_time; + bool found = false; + + debug("%s: Enter, %p, %p\n", __func__, dbx, cert); + + if (!cert) + return false; + + for (siglist = dbx; siglist; siglist = siglist->next) { + if (efi_search_siglist(cert, siglist, &revoc_time)) { + /* TODO */ + /* compare signing time with revocation time */ + + found = true; + break; + } + } + + debug("%s: Exit, verified: %d\n", __func__, !found); + return !found; +} + +/** + * efi_signature_verify_signers - verify signers' certificates with dbx + * @msg: Signature + * @dbx: Signature database + * + * Determine if any of signers' certificates in @msg may be verified + * by any of certificates in signature database pointed to by @dbx. + * This function is expected to be used against "dbx". + * + * Return: true if none of certificates is rejected, false otherwise. + */ +bool efi_signature_verify_signers(struct pkcs7_message *msg, + struct efi_signature_store *dbx) +{ + struct pkcs7_signed_info *info; + bool found = false; + + debug("%s: Enter, %p, %p\n", __func__, msg, dbx); + + if (!msg) + goto out; + + for (info = msg->signed_infos; info; info = info->next) { + if (info->signer && + !efi_signature_verify_cert(info->signer, dbx)) { + found = true; + goto out; + } + } +out: + debug("%s: Exit, verified: %d\n", __func__, !found); + return !found; +} + +/** + * efi_image_region_add - add an entry of region + * @regs: Pointer to array of regions + * @start: Start address of region + * @end: End address of region + * @nocheck: flag against overlapped regions + * + * Take one entry of region [@start, @end] and append it to the list + * pointed to by @regs. If @nocheck is false, overlapping among entries + * will be checked first. + * + * Return: 0 on success, status code (negative) on error + */ +efi_status_t efi_image_region_add(struct efi_image_regions *regs, + const void *start, const void *end, + int nocheck) +{ + struct image_region *reg; + int i, j; + + if (regs->num >= regs->max) { + debug("%s: no more room for regions\n", __func__); + return EFI_OUT_OF_RESOURCES; + } + + if (end < start) + return EFI_INVALID_PARAMETER; + + for (i = 0; i < regs->num; i++) { + reg = ®s->reg[i]; + if (nocheck) + continue; + + if (start > reg->data + reg->size) + continue; + + if ((start >= reg->data && start < reg->data + reg->size) || + (end > reg->data && end < reg->data + reg->size)) { + debug("%s: new region already part of another\n", + __func__); + return EFI_INVALID_PARAMETER; + } + + if (start < reg->data && end < reg->data + reg->size) { + for (j = regs->num - 1; j >= i; j--) + memcpy(®s->reg[j], ®s->reg[j + 1], + sizeof(*reg)); + break; + } + } + + reg = ®s->reg[i]; + reg->data = start; + reg->size = end - start; + regs->num++; + + return EFI_SUCCESS; +} +#endif /* CONFIG_EFI_SECURE_BOOT */
In this commit, implemented are a couple of helper functions which will be used to materialize variable authentication as well as image authentication in later patches. Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org> --- include/efi_api.h | 87 +++++ include/efi_loader.h | 72 ++++ lib/efi_loader/Makefile | 1 + lib/efi_loader/efi_signature.c | 583 +++++++++++++++++++++++++++++++++ 4 files changed, 743 insertions(+) create mode 100644 lib/efi_loader/efi_signature.c