Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752713AbdHDWFX (ORCPT ); Fri, 4 Aug 2017 18:05:23 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:56018 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752535AbdHDWFV (ORCPT ); Fri, 4 Aug 2017 18:05:21 -0400 From: Thiago Jung Bauermann To: linux-security-module@vger.kernel.org Cc: linux-ima-devel@lists.sourceforge.net, 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 Subject: [PATCH v4 3/7] PKCS#7: Introduce pkcs7_get_message_sig and verify_pkcs7_message_sig Date: Fri, 4 Aug 2017 19:03:26 -0300 X-Mailer: git-send-email 2.13.0 In-Reply-To: <20170804220330.30026-1-bauerman@linux.vnet.ibm.com> References: <20170804220330.30026-1-bauerman@linux.vnet.ibm.com> X-TM-AS-MML: disable x-cbid: 17080422-0024-0000-0000-000016F9CB89 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00007485; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000217; SDB=6.00897625; UDB=6.00449156; IPR=6.00677808; BA=6.00005510; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00016538; XFM=3.00000015; UTC=2017-08-04 22:05:18 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17080422-0025-0000-0000-00004C26AAD6 Message-Id: <20170804220330.30026-4-bauerman@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-08-04_12:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=3 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1706020000 definitions=main-1708040344 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6291 Lines: 169 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, -- 2.13.0