| Message ID | 20240702-b4-dynamic-uuid-v4-2-a00c82d1f504@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | efi: CapsuleUpdate: support for dynamic UUIDs | expand |
On 7/2/24 15:30, Caleb Connolly wrote: > Add support for generating version 5 UUIDs, these are determistic and work > by hashing a "namespace" UUID together with some unique data. One intended > usecase is to allow for dynamically generate payload UUIDs for UEFI > capsule updates, so that supported boards can have their own UUIDs > without needing to hardcode them. > > In addition, move the common bit twiddling code from gen_ran_uuid into a > separate function and rewrite it not to use clrsetbits (which is not > available when building as part of host tools). > > Tests for this are added in an upcoming patch. > > Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org> > --- > include/uuid.h | 17 +++++++++++++++-- > lib/Kconfig | 1 + > lib/uuid.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++------- > 3 files changed, 67 insertions(+), 9 deletions(-) > > diff --git a/include/uuid.h b/include/uuid.h > index f5a941250f48..1f4fa103b5e9 100644 > --- a/include/uuid.h > +++ b/include/uuid.h > @@ -10,8 +10,9 @@ > #ifndef __UUID_H__ > #define __UUID_H__ > > #include <linux/bitops.h> > +#include <linux/kconfig.h> > > /* > * UUID - Universally Unique IDentifier - 128 bits unique number. > * There are 5 versions and one variant of UUID defined by RFC4122 > @@ -45,10 +46,10 @@ > * where x is a hexadecimal character. Fields are separated by '-'s. > * When converting to a binary UUID, le means the field should be converted > * to little endian and be means it should be converted to big endian. > * > - * UUID is also used as GUID (Globally Unique Identifier) with the same binary > - * format but it differs in string format like below. > + * UUID is also used as GUID (Globally Unique Identifier) with the same format > + * but with some fields stored in little endian. > * > * GUID: > * 0 9 14 19 24 > * xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx > @@ -142,8 +143,20 @@ void gen_rand_uuid(unsigned char *uuid_bin); > * @param - uuid output type: UUID - 0, GUID - 1 > */ > void gen_rand_uuid_str(char *uuid_str, int str_format); > > +struct efi_guid; > + > +/** > + * gen_v5_guid() - generate little endian v5 GUID from namespace and other seed data. > + * > + * @namespace: pointer to UUID namespace salt > + * @guid: pointer to allocated GUID output > + * @...: NULL terminated list of seed data as pairs of pointers > + * to data and their lengths > + */ > +void gen_v5_guid(const struct uuid *namespace, struct efi_guid *guid, ...); > + > /** > * uuid_str_to_le_bin() - Convert string UUID to little endian binary data. > * @uuid_str: pointer to UUID string > * @uuid_bin: pointer to allocated array for little endian output [16B] > diff --git a/lib/Kconfig b/lib/Kconfig > index 189e6eb31aa1..9aa882d5f882 100644 > --- a/lib/Kconfig > +++ b/lib/Kconfig > @@ -72,8 +72,9 @@ config HAVE_PRIVATE_LIBGCC > bool > > config LIB_UUID > bool > + select SHA1 > > config RANDOM_UUID > bool "GPT Random UUID generation" > select LIB_UUID > diff --git a/lib/uuid.c b/lib/uuid.c > index dfa2320ba267..7d0a8273d157 100644 > --- a/lib/uuid.c > +++ b/lib/uuid.c > @@ -21,8 +21,9 @@ > #include <part_efi.h> > #include <malloc.h> > #include <dm/uclass.h> > #include <rng.h> > +#include <u-boot/sha1.h> > > int uuid_str_valid(const char *uuid) > { > int i, valid; > @@ -368,8 +369,57 @@ void uuid_bin_to_str(const unsigned char *uuid_bin, char *uuid_str, > } > } > } > > +static void configure_uuid(struct uuid *uuid, unsigned char version) > +{ > + uint16_t tmp; > + > + /* Configure variant/version bits */ > + tmp = be16_to_cpu(uuid->time_hi_and_version); > + tmp = (tmp & ~UUID_VERSION_MASK) | (version << UUID_VERSION_SHIFT); As you wrote above time_hi is stored low-endian in a GUID and big endian in UUID. So the version is in the byte 6 for a UUID and in byte 7 in a GUID. E.g. on my hard disk I find: Partition unique GUID: 003EF8CE-F7E9-467F-B80D-22ED2E6E93D7 CE F8 3E 00 E9 F7 7F 46 B8 0D 22 ED 2E 6E 93 D7 Where 4 is the version. > + uuid->time_hi_and_version = cpu_to_be16(tmp); > + > + uuid->clock_seq_hi_and_reserved &= ~UUID_VARIANT_MASK; > + uuid->clock_seq_hi_and_reserved |= (UUID_VARIANT << UUID_VARIANT_SHIFT); > +} > + > +void gen_v5_guid(const struct uuid *namespace, struct efi_guid *guid, ...) > +{ > + sha1_context ctx; > + va_list args; > + const uint8_t *data; > + uint32_t *tmp32; > + uint16_t *tmp16; > + uint8_t hash[SHA1_SUM_LEN]; > + > + sha1_starts(&ctx); > + /* Hash the namespace UUID as salt */ > + sha1_update(&ctx, (unsigned char *)namespace, UUID_BIN_LEN); > + va_start(args, guid); > + > + while ((data = va_arg(args, const uint8_t *))) { > + unsigned int len = va_arg(args, size_t); > + sha1_update(&ctx, data, len); > + } > + > + va_end(args); > + sha1_finish(&ctx, hash); > + > + /* Truncate the hash into output UUID, it is already big endian */ > + memcpy(guid, hash, sizeof(*guid)); > + > + configure_uuid((struct uuid *)guid, 5); Please, provide a test that in the resulting GUID output we find the variant and version information at the expected places: The high nibble of the byte with index 7 should be 5. The high nibble of the byte with index 8 should 8, 9, C, or D. > + > + /* Make little endian */ > + tmp32 = (uint32_t *)&guid->b[0]; > + *tmp32 = be32_to_cpu(*tmp32); > + tmp16 = (uint16_t *)&guid->b[4]; > + *tmp16 = be16_to_cpu(*tmp16); > + tmp16 = (uint16_t *)&guid->b[6]; > + *tmp16 = be16_to_cpu(*tmp16); > +} > + > #if defined(CONFIG_RANDOM_UUID) || defined(CONFIG_CMD_UUID) > void gen_rand_uuid(unsigned char *uuid_bin) > { > u32 ptr[4]; > @@ -394,15 +444,9 @@ void gen_rand_uuid(unsigned char *uuid_bin) > /* Set all fields randomly */ > for (i = 0; i < 4; i++) > ptr[i] = rand(); > > - clrsetbits_be16(&uuid->time_hi_and_version, > - UUID_VERSION_MASK, > - UUID_VERSION << UUID_VERSION_SHIFT); > - > - clrsetbits_8(&uuid->clock_seq_hi_and_reserved, > - UUID_VARIANT_MASK, > - UUID_VARIANT << UUID_VARIANT_SHIFT); > + configure_uuid(uuid, UUID_VERSION); Please, provide a test that in the resulting UUID output we find the variant and version information at the expected places: The high nibble of the byte with index 6 should be 4. The high nibble of the byte with index 8 should 8, 9, C, or D. Best regards Heinrich > > memcpy(uuid_bin, uuid, 16); > } > >
diff --git a/include/uuid.h b/include/uuid.h index f5a941250f48..1f4fa103b5e9 100644 --- a/include/uuid.h +++ b/include/uuid.h @@ -10,8 +10,9 @@ #ifndef __UUID_H__ #define __UUID_H__ #include <linux/bitops.h> +#include <linux/kconfig.h> /* * UUID - Universally Unique IDentifier - 128 bits unique number. * There are 5 versions and one variant of UUID defined by RFC4122 @@ -45,10 +46,10 @@ * where x is a hexadecimal character. Fields are separated by '-'s. * When converting to a binary UUID, le means the field should be converted * to little endian and be means it should be converted to big endian. * - * UUID is also used as GUID (Globally Unique Identifier) with the same binary - * format but it differs in string format like below. + * UUID is also used as GUID (Globally Unique Identifier) with the same format + * but with some fields stored in little endian. * * GUID: * 0 9 14 19 24 * xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx @@ -142,8 +143,20 @@ void gen_rand_uuid(unsigned char *uuid_bin); * @param - uuid output type: UUID - 0, GUID - 1 */ void gen_rand_uuid_str(char *uuid_str, int str_format); +struct efi_guid; + +/** + * gen_v5_guid() - generate little endian v5 GUID from namespace and other seed data. + * + * @namespace: pointer to UUID namespace salt + * @guid: pointer to allocated GUID output + * @...: NULL terminated list of seed data as pairs of pointers + * to data and their lengths + */ +void gen_v5_guid(const struct uuid *namespace, struct efi_guid *guid, ...); + /** * uuid_str_to_le_bin() - Convert string UUID to little endian binary data. * @uuid_str: pointer to UUID string * @uuid_bin: pointer to allocated array for little endian output [16B] diff --git a/lib/Kconfig b/lib/Kconfig index 189e6eb31aa1..9aa882d5f882 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -72,8 +72,9 @@ config HAVE_PRIVATE_LIBGCC bool config LIB_UUID bool + select SHA1 config RANDOM_UUID bool "GPT Random UUID generation" select LIB_UUID diff --git a/lib/uuid.c b/lib/uuid.c index dfa2320ba267..7d0a8273d157 100644 --- a/lib/uuid.c +++ b/lib/uuid.c @@ -21,8 +21,9 @@ #include <part_efi.h> #include <malloc.h> #include <dm/uclass.h> #include <rng.h> +#include <u-boot/sha1.h> int uuid_str_valid(const char *uuid) { int i, valid; @@ -368,8 +369,57 @@ void uuid_bin_to_str(const unsigned char *uuid_bin, char *uuid_str, } } } +static void configure_uuid(struct uuid *uuid, unsigned char version) +{ + uint16_t tmp; + + /* Configure variant/version bits */ + tmp = be16_to_cpu(uuid->time_hi_and_version); + tmp = (tmp & ~UUID_VERSION_MASK) | (version << UUID_VERSION_SHIFT); + uuid->time_hi_and_version = cpu_to_be16(tmp); + + uuid->clock_seq_hi_and_reserved &= ~UUID_VARIANT_MASK; + uuid->clock_seq_hi_and_reserved |= (UUID_VARIANT << UUID_VARIANT_SHIFT); +} + +void gen_v5_guid(const struct uuid *namespace, struct efi_guid *guid, ...) +{ + sha1_context ctx; + va_list args; + const uint8_t *data; + uint32_t *tmp32; + uint16_t *tmp16; + uint8_t hash[SHA1_SUM_LEN]; + + sha1_starts(&ctx); + /* Hash the namespace UUID as salt */ + sha1_update(&ctx, (unsigned char *)namespace, UUID_BIN_LEN); + va_start(args, guid); + + while ((data = va_arg(args, const uint8_t *))) { + unsigned int len = va_arg(args, size_t); + sha1_update(&ctx, data, len); + } + + va_end(args); + sha1_finish(&ctx, hash); + + /* Truncate the hash into output UUID, it is already big endian */ + memcpy(guid, hash, sizeof(*guid)); + + configure_uuid((struct uuid *)guid, 5); + + /* Make little endian */ + tmp32 = (uint32_t *)&guid->b[0]; + *tmp32 = be32_to_cpu(*tmp32); + tmp16 = (uint16_t *)&guid->b[4]; + *tmp16 = be16_to_cpu(*tmp16); + tmp16 = (uint16_t *)&guid->b[6]; + *tmp16 = be16_to_cpu(*tmp16); +} + #if defined(CONFIG_RANDOM_UUID) || defined(CONFIG_CMD_UUID) void gen_rand_uuid(unsigned char *uuid_bin) { u32 ptr[4]; @@ -394,15 +444,9 @@ void gen_rand_uuid(unsigned char *uuid_bin) /* Set all fields randomly */ for (i = 0; i < 4; i++) ptr[i] = rand(); - clrsetbits_be16(&uuid->time_hi_and_version, - UUID_VERSION_MASK, - UUID_VERSION << UUID_VERSION_SHIFT); - - clrsetbits_8(&uuid->clock_seq_hi_and_reserved, - UUID_VARIANT_MASK, - UUID_VARIANT << UUID_VARIANT_SHIFT); + configure_uuid(uuid, UUID_VERSION); memcpy(uuid_bin, uuid, 16); }
Add support for generating version 5 UUIDs, these are determistic and work by hashing a "namespace" UUID together with some unique data. One intended usecase is to allow for dynamically generate payload UUIDs for UEFI capsule updates, so that supported boards can have their own UUIDs without needing to hardcode them. In addition, move the common bit twiddling code from gen_ran_uuid into a separate function and rewrite it not to use clrsetbits (which is not available when building as part of host tools). Tests for this are added in an upcoming patch. Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org> --- include/uuid.h | 17 +++++++++++++++-- lib/Kconfig | 1 + lib/uuid.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++------- 3 files changed, 67 insertions(+), 9 deletions(-)