From patchwork Thu Nov 5 04:24:05 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Lee, Chun-Yi" X-Patchwork-Id: 317924 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B3036C4742C for ; Thu, 5 Nov 2020 04:24:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6891620825 for ; Thu, 5 Nov 2020 04:24:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="fsdDrj9u" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731169AbgKEEYe (ORCPT ); Wed, 4 Nov 2020 23:24:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34906 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731123AbgKEEYc (ORCPT ); Wed, 4 Nov 2020 23:24:32 -0500 Received: from mail-pf1-x443.google.com (mail-pf1-x443.google.com [IPv6:2607:f8b0:4864:20::443]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8DCE7C0613CF; Wed, 4 Nov 2020 20:24:32 -0800 (PST) Received: by mail-pf1-x443.google.com with SMTP id x13so352940pfa.9; Wed, 04 Nov 2020 20:24:32 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=Fk1XjhsIVpehEyUHjISdm6QYmnqvAVbB3cg/2P5Gk18=; b=fsdDrj9ulrPJymyx5BMLxNn/9u3dFjjW3GuKGSis2ZqEO+5vgwbnLLa6DwGBp2Mo1F 6oNXLNPYHrASASdw/N9mIaGJHDOoK+SafQXeEC7Y+HS3Eos9u8QT4RtRBbZqau5rLpV8 siPoWc1Aam1/XLWeSftRSleELG0MD7xEGPFBkcb0mADRrHjzi2cJVmhnmBD6lCgDhxyx vY1KYea19IXOUQgG7EBo/26D4nMjcgh5VbJvzzLpoFz5mRAvoB4FcEMouIXQCcELO2SN TFPZqM5eFzbRKN2CNI4tITgg5M6U74vuny+khO8L4hhA+iimBQF0+lGvC7S9IM022O/t LRqw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=Fk1XjhsIVpehEyUHjISdm6QYmnqvAVbB3cg/2P5Gk18=; b=HPAao61VQEblQuGGoGGeMyzNMAsIX8iRLCOAtAA+Z8OrvriuacctZZs6FzkWe6DTdd efvX1BFbMdlHpBTPpkHHa+KBPA3E5vonjnLQiHr/V1hcbu4E8NBHaiEd9uGugbTNFpxx u4njpsJB3cC7Ok0LcA3EsdZtiikL5weXQHxd/9o/taGjcwjcCT/3E2C+gS0PDzOlYl1z Vvf9HtCGb5fdJ/OxIu2NGMQhyyWuyGY+65cOvxPC66uLHqIXke4h1e7DJtklcGTIl+pv W6KdOXHT36082xFHiKu8ABU3zcQ+wVH/2yzYNXayA4f6KApfr525+L0Skg3WTolYR89z 9+QQ== X-Gm-Message-State: AOAM532R70TZk49egSsMcO8ALDdA8B3cnjmQs/ooSmLbk6EXPhsTfSZ/ lLQCKMODaAphX5qLknp8rM2YSsGp8Bs= X-Google-Smtp-Source: ABdhPJwYYSxIsD0L45wrkYlchreKYoRYL2ClZqiXC3s448F8zN8aaIH/bi2tvRIgr3i1LEht9iXkwA== X-Received: by 2002:a05:6a00:22c6:b029:18b:3bb8:8b6d with SMTP id f6-20020a056a0022c6b029018b3bb88b6dmr607779pfj.31.1604550272199; Wed, 04 Nov 2020 20:24:32 -0800 (PST) Received: from linux-l9pv.suse ([124.11.22.254]) by smtp.gmail.com with ESMTPSA id z22sm472782pfa.220.2020.11.04.20.24.29 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 04 Nov 2020 20:24:31 -0800 (PST) From: "Lee, Chun-Yi" X-Google-Original-From: "Lee, Chun-Yi" To: David Howells Cc: Herbert Xu , "David S . Miller" , Ben Boeckel , Randy Dunlap , keyrings@vger.kernel.org, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, "Lee, Chun-Yi" Subject: [PATCH v2 1/2] X.509: Add CodeSigning extended key usage parsing Date: Thu, 5 Nov 2020 12:24:05 +0800 Message-Id: <20201105042406.5783-2-jlee@suse.com> X-Mailer: git-send-email 2.12.3 In-Reply-To: <20201105042406.5783-1-jlee@suse.com> References: <20201105042406.5783-1-jlee@suse.com> Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org This patch adds the logic for parsing the CodeSign extended key usage extension in X.509. The parsing result will be set to the eku flag which is carried by public key. It can be used in the PKCS#7 verification. Signed-off-by: "Lee, Chun-Yi" --- crypto/asymmetric_keys/x509_cert_parser.c | 24 ++++++++++++++++++++++++ include/crypto/public_key.h | 1 + include/linux/oid_registry.h | 5 +++++ 3 files changed, 30 insertions(+) diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c index 52c9b455fc7d..65721313b265 100644 --- a/crypto/asymmetric_keys/x509_cert_parser.c +++ b/crypto/asymmetric_keys/x509_cert_parser.c @@ -497,6 +497,8 @@ int x509_process_extension(void *context, size_t hdrlen, struct x509_parse_context *ctx = context; struct asymmetric_key_id *kid; const unsigned char *v = value; + int i = 0; + enum OID oid; pr_debug("Extension: %u\n", ctx->last_oid); @@ -526,6 +528,28 @@ int x509_process_extension(void *context, size_t hdrlen, return 0; } + if (ctx->last_oid == OID_extKeyUsage) { + if (v[0] != ((ASN1_UNIV << 6) | ASN1_CONS_BIT | ASN1_SEQ) || + v[1] != vlen - 2) + return -EBADMSG; + i += 2; + + while (i < vlen) { + /* A 10 bytes EKU OID Octet blob = + * ASN1_OID + size byte + 8 bytes OID */ + if (v[i] != ASN1_OID || v[i + 1] != 8 || (i + 10) > vlen) + return -EBADMSG; + + oid = look_up_OID(v + i + 2, v[i + 1]); + if (oid == OID_codeSigning) { + ctx->cert->pub->eku |= EKU_codeSigning; + } + i += 10; + } + pr_debug("extKeyUsage: %d\n", ctx->cert->pub->eku); + return 0; + } + return 0; } diff --git a/include/crypto/public_key.h b/include/crypto/public_key.h index 948c5203ca9c..07a1b28460a2 100644 --- a/include/crypto/public_key.h +++ b/include/crypto/public_key.h @@ -29,6 +29,7 @@ struct public_key { bool key_is_private; const char *id_type; const char *pkey_algo; + unsigned int eku : 9; /* Extended Key Usage (9-bit) */ }; extern void public_key_free(struct public_key *key); diff --git a/include/linux/oid_registry.h b/include/linux/oid_registry.h index 4462ed2c18cd..e20e8eb53b21 100644 --- a/include/linux/oid_registry.h +++ b/include/linux/oid_registry.h @@ -113,9 +113,14 @@ enum OID { OID_SM2_with_SM3, /* 1.2.156.10197.1.501 */ OID_sm3WithRSAEncryption, /* 1.2.156.10197.1.504 */ + /* Extended key purpose OIDs [RFC 5280] */ + OID_codeSigning, /* 1.3.6.1.5.5.7.3.3 */ + OID__NR }; +#define EKU_codeSigning (1 << 2) + extern enum OID look_up_OID(const void *data, size_t datasize); extern int sprint_oid(const void *, size_t, char *, size_t); extern int sprint_OID(enum OID, char *, size_t); From patchwork Thu Nov 5 04:24:06 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Lee, Chun-Yi" X-Patchwork-Id: 319456 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4E16DC388F9 for ; Thu, 5 Nov 2020 04:25:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E9B2120795 for ; 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Wed, 04 Nov 2020 20:24:58 -0800 (PST) Received: from linux-l9pv.suse ([124.11.22.254]) by smtp.gmail.com with ESMTPSA id z22sm472782pfa.220.2020.11.04.20.24.55 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 04 Nov 2020 20:24:58 -0800 (PST) From: "Lee, Chun-Yi" X-Google-Original-From: "Lee, Chun-Yi" To: David Howells Cc: Herbert Xu , "David S . Miller" , Ben Boeckel , Randy Dunlap , keyrings@vger.kernel.org, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, "Lee, Chun-Yi" Subject: [PATCH v2 2/2] PKCS#7: Check codeSigning EKU for kernel module and kexec pe verification Date: Thu, 5 Nov 2020 12:24:06 +0800 Message-Id: <20201105042406.5783-3-jlee@suse.com> X-Mailer: git-send-email 2.12.3 In-Reply-To: <20201105042406.5783-1-jlee@suse.com> References: <20201105042406.5783-1-jlee@suse.com> Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org This patch adds the logic for checking the CodeSigning extended key usage when verifying signature of kernel module or kexec PE binary in PKCS#7. Signed-off-by: "Lee, Chun-Yi" --- certs/system_keyring.c | 2 +- crypto/asymmetric_keys/Kconfig | 9 +++++++++ crypto/asymmetric_keys/pkcs7_trust.c | 37 +++++++++++++++++++++++++++++++++--- include/crypto/pkcs7.h | 3 ++- 4 files changed, 46 insertions(+), 5 deletions(-) diff --git a/certs/system_keyring.c b/certs/system_keyring.c index 798291177186..4104f5465d8a 100644 --- a/certs/system_keyring.c +++ b/certs/system_keyring.c @@ -242,7 +242,7 @@ int verify_pkcs7_message_sig(const void *data, size_t len, goto error; } } - ret = pkcs7_validate_trust(pkcs7, trusted_keys); + ret = pkcs7_validate_trust(pkcs7, trusted_keys, usage); if (ret < 0) { if (ret == -ENOKEY) pr_devel("PKCS#7 signature not signed with a trusted key\n"); diff --git a/crypto/asymmetric_keys/Kconfig b/crypto/asymmetric_keys/Kconfig index 1f1f004dc757..1754812df989 100644 --- a/crypto/asymmetric_keys/Kconfig +++ b/crypto/asymmetric_keys/Kconfig @@ -96,4 +96,13 @@ config SIGNED_PE_FILE_VERIFICATION This option provides support for verifying the signature(s) on a signed PE binary. +config CHECK_CODESIGN_EKU + bool "Check codeSigning extended key usage" + depends on PKCS7_MESSAGE_PARSER=y + depends on SYSTEM_DATA_VERIFICATION + help + This option provides support for checking the codeSigning extended + key usage when verifying the signature in PKCS#7. It affects kernel + module verification and kexec PE binary verification. + endif # ASYMMETRIC_KEY_TYPE diff --git a/crypto/asymmetric_keys/pkcs7_trust.c b/crypto/asymmetric_keys/pkcs7_trust.c index 61af3c4d82cc..1d2318ff63db 100644 --- a/crypto/asymmetric_keys/pkcs7_trust.c +++ b/crypto/asymmetric_keys/pkcs7_trust.c @@ -16,12 +16,36 @@ #include #include "pkcs7_parser.h" +#ifdef CONFIG_CHECK_CODESIGN_EKU +static bool check_codesign_eku(struct key *key, + enum key_being_used_for usage) +{ + struct public_key *public_key = key->payload.data[asym_crypto]; + + switch (usage) { + case VERIFYING_MODULE_SIGNATURE: + case VERIFYING_KEXEC_PE_SIGNATURE: + return !!(public_key->eku & EKU_codeSigning); + default: + break; + } + return true; +} +#else +static bool check_codesign_eku(struct key *key, + enum key_being_used_for usage) +{ + return true; +} +#endif + /** * Check the trust on one PKCS#7 SignedInfo block. */ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7, struct pkcs7_signed_info *sinfo, - struct key *trust_keyring) + struct key *trust_keyring, + enum key_being_used_for usage) { struct public_key_signature *sig = sinfo->sig; struct x509_certificate *x509, *last = NULL, *p; @@ -112,6 +136,12 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7, return -ENOKEY; matched: + if (!check_codesign_eku(key, usage)) { + pr_warn("sinfo %u: The signer %x key is not CodeSigning\n", + sinfo->index, key_serial(key)); + key_put(key); + return -ENOKEY; + } ret = verify_signature(key, sig); key_put(key); if (ret < 0) { @@ -156,7 +186,8 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7, * May also return -ENOMEM. */ int pkcs7_validate_trust(struct pkcs7_message *pkcs7, - struct key *trust_keyring) + struct key *trust_keyring, + enum key_being_used_for usage) { struct pkcs7_signed_info *sinfo; struct x509_certificate *p; @@ -167,7 +198,7 @@ int pkcs7_validate_trust(struct pkcs7_message *pkcs7, p->seen = false; for (sinfo = pkcs7->signed_infos; sinfo; sinfo = sinfo->next) { - ret = pkcs7_validate_trust_one(pkcs7, sinfo, trust_keyring); + ret = pkcs7_validate_trust_one(pkcs7, sinfo, trust_keyring, usage); switch (ret) { case -ENOKEY: continue; diff --git a/include/crypto/pkcs7.h b/include/crypto/pkcs7.h index 38ec7f5f9041..b3b48240ba73 100644 --- a/include/crypto/pkcs7.h +++ b/include/crypto/pkcs7.h @@ -30,7 +30,8 @@ extern int pkcs7_get_content_data(const struct pkcs7_message *pkcs7, * pkcs7_trust.c */ extern int pkcs7_validate_trust(struct pkcs7_message *pkcs7, - struct key *trust_keyring); + struct key *trust_keyring, + enum key_being_used_for usage); /* * pkcs7_verify.c