From: Thiago Jung Bauermann Subject: [PATCH v5 13/18] PKCS#7: Introduce pkcs7_get_message_sig and verify_pkcs7_message_sig Date: Tue, 17 Oct 2017 22:53:26 -0200 Message-ID: <20171018005331.2688-14-bauerman@linux.vnet.ibm.com> References: <20171018005331.2688-1-bauerman@linux.vnet.ibm.com> Cc: linux-security-module@vger.kernel.org, keyrings@vger.kernel.org, linux-crypto@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, Mimi Zohar , Dmitry Kasatkin , James Morris , "Serge E. Hallyn" , David Howells , David Woodhouse , Jessica Yu , Rusty Russell , Herbert Xu , "David S. Miller" , "AKASHI, Takahiro" , Thiago Jung Bauermann To: linux-integrity@vger.kernel.org Return-path: Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:56654 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1761835AbdJRAzG (ORCPT ); Tue, 17 Oct 2017 20:55:06 -0400 Received: from pps.filterd (m0098413.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id v9I0rVoT131952 for ; Tue, 17 Oct 2017 20:55:05 -0400 Received: from e11.ny.us.ibm.com (e11.ny.us.ibm.com [129.33.205.201]) by mx0b-001b2d01.pphosted.com with ESMTP id 2dntfh4ych-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Tue, 17 Oct 2017 20:55:05 -0400 Received: from localhost by e11.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 17 Oct 2017 20:55:04 -0400 In-Reply-To: <20171018005331.2688-1-bauerman@linux.vnet.ibm.com> Sender: linux-crypto-owner@vger.kernel.org List-ID: IMA will need to access the digest used in the signature so that it can verify files containing module-style appended signatures. For this purpose, add function pkcs7_get_message_sig. It will also need to verify an already parsed PKCS#7 message. For this purpose, add function verify_pkcs7_message_signature which takes a struct pkcs7_message for verification instead of the raw bytes that verify_pkcs7_signature takes. Signed-off-by: Thiago Jung Bauermann --- certs/system_keyring.c | 60 +++++++++++++++++++++++++---------- crypto/asymmetric_keys/pkcs7_parser.c | 12 +++++++ include/crypto/pkcs7.h | 2 ++ include/linux/verification.h | 10 ++++++ 4 files changed, 68 insertions(+), 16 deletions(-) diff --git a/certs/system_keyring.c b/certs/system_keyring.c index 6251d1b27f0c..6a8684959780 100644 --- a/certs/system_keyring.c +++ b/certs/system_keyring.c @@ -190,33 +190,26 @@ late_initcall(load_system_certificate_list); #ifdef CONFIG_SYSTEM_DATA_VERIFICATION /** - * verify_pkcs7_signature - Verify a PKCS#7-based signature on system data. + * verify_pkcs7_message_sig - Verify a PKCS#7-based signature on system data. * @data: The data to be verified (NULL if expecting internal data). * @len: Size of @data. - * @raw_pkcs7: The PKCS#7 message that is the signature. - * @pkcs7_len: The size of @raw_pkcs7. + * @pkcs7: The PKCS#7 message that is the signature. * @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only, * (void *)1UL for all trusted keys). * @usage: The use to which the key is being put. * @view_content: Callback to gain access to content. * @ctx: Context for callback. */ -int verify_pkcs7_signature(const void *data, size_t len, - const void *raw_pkcs7, size_t pkcs7_len, - struct key *trusted_keys, - enum key_being_used_for usage, - int (*view_content)(void *ctx, - const void *data, size_t len, - size_t asn1hdrlen), - void *ctx) +int verify_pkcs7_message_sig(const void *data, size_t len, + struct pkcs7_message *pkcs7, + struct key *trusted_keys, + enum key_being_used_for usage, + int (*view_content)(void *ctx, const void *data, + size_t len, size_t asn1hdrlen), + void *ctx) { - struct pkcs7_message *pkcs7; int ret; - pkcs7 = pkcs7_parse_message(raw_pkcs7, pkcs7_len); - if (IS_ERR(pkcs7)) - return PTR_ERR(pkcs7); - /* The data should be detached - so we need to supply it. */ if (data && pkcs7_supply_detached_data(pkcs7, data, len) < 0) { pr_err("PKCS#7 signature with non-detached data\n"); @@ -258,6 +251,41 @@ int verify_pkcs7_signature(const void *data, size_t len, } error: + pr_devel("<==%s() = %d\n", __func__, ret); + return ret; +} + +/** + * verify_pkcs7_signature - Verify a PKCS#7-based signature on system data. + * @data: The data to be verified (NULL if expecting internal data). + * @len: Size of @data. + * @raw_pkcs7: The PKCS#7 message that is the signature. + * @pkcs7_len: The size of @raw_pkcs7. + * @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only, + * (void *)1UL for all trusted keys). + * @usage: The use to which the key is being put. + * @view_content: Callback to gain access to content. + * @ctx: Context for callback. + */ +int verify_pkcs7_signature(const void *data, size_t len, + const void *raw_pkcs7, size_t pkcs7_len, + struct key *trusted_keys, + enum key_being_used_for usage, + int (*view_content)(void *ctx, + const void *data, size_t len, + size_t asn1hdrlen), + void *ctx) +{ + struct pkcs7_message *pkcs7; + int ret; + + pkcs7 = pkcs7_parse_message(raw_pkcs7, pkcs7_len); + if (IS_ERR(pkcs7)) + return PTR_ERR(pkcs7); + + ret = verify_pkcs7_message_sig(data, len, pkcs7, trusted_keys, usage, + view_content, ctx); + pkcs7_free_message(pkcs7); pr_devel("<==%s() = %d\n", __func__, ret); return ret; diff --git a/crypto/asymmetric_keys/pkcs7_parser.c b/crypto/asymmetric_keys/pkcs7_parser.c index af4cd8649117..e41beda297a8 100644 --- a/crypto/asymmetric_keys/pkcs7_parser.c +++ b/crypto/asymmetric_keys/pkcs7_parser.c @@ -673,3 +673,15 @@ int pkcs7_note_signed_info(void *context, size_t hdrlen, return -ENOMEM; return 0; } + +/** + * pkcs7_get_message_sig - get signature in @pkcs7 + * + * This function doesn't meaningfully support messages with more than one + * signature. It will always return the first signature. + */ +const struct public_key_signature *pkcs7_get_message_sig( + const struct pkcs7_message *pkcs7) +{ + return pkcs7->signed_infos ? pkcs7->signed_infos->sig : NULL; +} diff --git a/include/crypto/pkcs7.h b/include/crypto/pkcs7.h index 583f199400a3..6f51d0cb6d12 100644 --- a/include/crypto/pkcs7.h +++ b/include/crypto/pkcs7.h @@ -28,6 +28,8 @@ extern void pkcs7_free_message(struct pkcs7_message *pkcs7); extern int pkcs7_get_content_data(const struct pkcs7_message *pkcs7, const void **_data, size_t *_datalen, size_t *_headerlen); +extern const struct public_key_signature *pkcs7_get_message_sig( + const struct pkcs7_message *pkcs7); /* * pkcs7_trust.c diff --git a/include/linux/verification.h b/include/linux/verification.h index a10549a6c7cd..f04dac2728ec 100644 --- a/include/linux/verification.h +++ b/include/linux/verification.h @@ -29,6 +29,7 @@ extern const char *const key_being_used_for[NR__KEY_BEING_USED_FOR]; #ifdef CONFIG_SYSTEM_DATA_VERIFICATION struct key; +struct pkcs7_message; extern int verify_pkcs7_signature(const void *data, size_t len, const void *raw_pkcs7, size_t pkcs7_len, @@ -38,6 +39,15 @@ extern int verify_pkcs7_signature(const void *data, size_t len, const void *data, size_t len, size_t asn1hdrlen), void *ctx); +extern int verify_pkcs7_message_sig(const void *data, size_t len, + struct pkcs7_message *pkcs7, + struct key *trusted_keys, + enum key_being_used_for usage, + int (*view_content)(void *ctx, + const void *data, + size_t len, + size_t asn1hdrlen), + void *ctx); #ifdef CONFIG_SIGNED_PE_FILE_VERIFICATION extern int verify_pefile_signature(const void *pebuf, unsigned pelen,