From 9f1789bb05bcfd946f963d967b380e52209f5f8f Mon Sep 17 00:00:00 2001 From: Raymond Mao Date: Mon, 4 Mar 2024 09:28:53 -0800 Subject: [PATCH] lib/crypto: port PKCS7 parser on MbedTLS Integrate PKCS7 parser on top of MbedTLS PKCS7 library. Signed-off-by: Raymond Mao --- include/crypto/pkcs7_parser.h | 55 ++++ lib/crypto/pkcs7_parser.c | 482 ++++++++++++++++++++++++++++++++-- 2 files changed, 509 insertions(+), 28 deletions(-) diff --git a/include/crypto/pkcs7_parser.h b/include/crypto/pkcs7_parser.h index 2c45cce5234..4802779df6d 100644 --- a/include/crypto/pkcs7_parser.h +++ b/include/crypto/pkcs7_parser.h @@ -11,6 +11,11 @@ #include #include #include +#if CONFIG_IS_ENABLED(MBEDTLS_LIB_X509) +#include +#include +#include +#endif #include #define kenter(FMT, ...) \ @@ -18,7 +23,54 @@ #define kleave(FMT, ...) \ pr_devel("<== %s()"FMT"\n", __func__, ##__VA_ARGS__) +/* Backup the parsed MedTLS context that we need */ +#if CONFIG_IS_ENABLED(MBEDTLS_LIB_X509) +struct pkcs7_mbedtls_ctx { + void *content_data; +}; + +struct pkcs7_sinfo_mbedtls_ctx { + void *authattrs_data; + void *content_data_digest; +}; +#endif + +/* + * MbedTLS integration Notes: + * + * MbedTLS PKCS#7 library does not originally support parsing MicroSoft + * Authentication Code which is used for verifying the PE image digest. + * + * 1. Authenticated Attributes (authenticatedAttributes) + * MbedTLS assumes unauthenticatedAttributes and authenticatedAttributes + * fields not exist. + * See MbedTLS function 'pkcs7_get_signer_info' for details. + * + * 2. MicroSoft Authentication Code (mscode) + * MbedTLS only supports Content Data type defined as 1.2.840.113549.1.7.1 + * (MBEDTLS_OID_PKCS7_DATA, aka OID_data). + * 1.3.6.1.4.1.311.2.1.4 (MicroSoft Authentication Code, aka + * OID_msIndirectData) is not supported. + * See MbedTLS function 'pkcs7_get_content_info_type' for details. + * + * But the EFI loader assumes that a PKCS#7 message with an EFI image always + * contains MicroSoft Authentication Code as Content Data (msg->data is NOT + * NULL), see function 'efi_signature_verify'. + * + * MbedTLS patch "0002-support-MicroSoft-authentication-code-in-PKCS7-lib.patch" + * is to support both above features by parsing the Content Data and + * Authenticate Attributes from a given PKCS#7 message. + * + * Other fields we don't need to populate from MbedTLS, which are used + * internally by pkcs7_verify: + * 'signer', 'unsupported_crypto', 'blacklisted' + * 'sig->digest' is used internally by pkcs7_digest to calculate the hash of + * Content Data or Authenticate Attributes. + */ struct pkcs7_signed_info { +#if CONFIG_IS_ENABLED(MBEDTLS_LIB_X509) + struct pkcs7_sinfo_mbedtls_ctx *mbedtls_ctx; +#endif struct pkcs7_signed_info *next; struct x509_certificate *signer; /* Signing certificate (in msg->certs) */ unsigned index; @@ -55,6 +107,9 @@ struct pkcs7_signed_info { }; struct pkcs7_message { +#if CONFIG_IS_ENABLED(MBEDTLS_LIB_X509) + struct pkcs7_mbedtls_ctx *mbedtls_ctx; +#endif struct x509_certificate *certs; /* Certificate list */ struct x509_certificate *crl; /* Revocation list */ struct pkcs7_signed_info *signed_infos; diff --git a/lib/crypto/pkcs7_parser.c b/lib/crypto/pkcs7_parser.c index d5efa828d6a..3c819d934e3 100644 --- a/lib/crypto/pkcs7_parser.c +++ b/lib/crypto/pkcs7_parser.c @@ -27,7 +27,9 @@ #else #include "pkcs7_parser.h" #endif +#if !CONFIG_IS_ENABLED(MBEDTLS_LIB_X509) #include "pkcs7.asn1.h" +#endif MODULE_DESCRIPTION("PKCS#7 parser"); MODULE_AUTHOR("Red Hat, Inc."); @@ -52,6 +54,352 @@ struct pkcs7_parse_context { bool expect_skid; }; +#if CONFIG_IS_ENABLED(MBEDTLS_LIB_X509) + +static void pkcs7_free_mbedtls_ctx(struct pkcs7_mbedtls_ctx *ctx) +{ + if (ctx) { + kfree(ctx->content_data); + kfree(ctx); + } +} + +static void pkcs7_free_sinfo_mbedtls_ctx(struct pkcs7_sinfo_mbedtls_ctx *ctx) +{ + if (ctx) { + kfree(ctx->authattrs_data); + kfree(ctx->content_data_digest); + kfree(ctx); + } +} + +/* + * Parse Authenticate Attributes + * TODO: Shall we consider to integrate decoding of authenticate attribute into + * MbedTLS library? + * + * Structure of the data: + * + * [C.P.0] { + * U.P.SEQUENCE { + * U.P.OBJECTIDENTIFIER + * U.P.SET { + * U.P.OBJECTIDENTIFIER + * } + * } + * U.P.SEQUENCE { + * U.P.OBJECTIDENTIFIER + * U.P.SET { + * U.P.UTCTime + * } + * } + * U.P.SEQUENCE { + * U.P.OBJECTIDENTIFIER + * U.P.SET { + * U.P.OCTETSTRING + * } + * } + * U.P.SEQUENCE { + * U.P.OBJECTIDENTIFIER + * U.P.SET { + * U.P.SEQUENCE { + * [...] + * } + * } + * } + * } + */ +static int authattrs_parse(struct pkcs7_message *msg, void *aa, size_t aa_len, + struct pkcs7_signed_info *sinfo) +{ + unsigned char *p = (unsigned char *)aa; + unsigned char *end = (unsigned char *)aa + aa_len; + size_t len = 0; + int ret; + unsigned char *inner_p; + size_t seq_len = 0; + + ret = mbedtls_asn1_get_tag(&p, end, &seq_len, + MBEDTLS_ASN1_CONTEXT_SPECIFIC | + MBEDTLS_ASN1_CONSTRUCTED); + if (ret) + return ret; + + while (!mbedtls_asn1_get_tag(&p, end, &seq_len, + MBEDTLS_ASN1_CONSTRUCTED | + MBEDTLS_ASN1_SEQUENCE)) { + inner_p = p; + ret = mbedtls_asn1_get_tag(&inner_p, p + seq_len, &len, + MBEDTLS_ASN1_OID); + if (ret) + return ret; + + if (!MBEDTLS_OID_CMP_RAW(MBEDTLS_OID_PKCS9_CONTENTTYPE, inner_p, len)) { + inner_p += len; + ret = mbedtls_asn1_get_tag(&inner_p, p + seq_len, &len, + MBEDTLS_ASN1_CONSTRUCTED | + MBEDTLS_ASN1_SET); + if (ret) + return ret; + + ret = mbedtls_asn1_get_tag(&inner_p, p + seq_len, &len, + MBEDTLS_ASN1_OID); + if (ret) + return ret; + + if (MBEDTLS_OID_CMP_RAW(MBEDTLS_OID_MICROSOFT_INDIRECTDATA, + inner_p, len)) + return -EINVAL; + + if (__test_and_set_bit(sinfo_has_content_type, &sinfo->aa_set)) + return -EINVAL; + } else if (!MBEDTLS_OID_CMP_RAW(MBEDTLS_OID_PKCS9_MESSAGEDIGEST, inner_p, + len)) { + inner_p += len; + ret = mbedtls_asn1_get_tag(&inner_p, p + seq_len, &len, + MBEDTLS_ASN1_CONSTRUCTED | + MBEDTLS_ASN1_SET); + if (ret) + return ret; + + ret = mbedtls_asn1_get_tag(&inner_p, p + seq_len, &len, + MBEDTLS_ASN1_OCTET_STRING); + if (ret) + return ret; + + sinfo->msgdigest = inner_p; + sinfo->msgdigest_len = len; + + if (__test_and_set_bit(sinfo_has_message_digest, &sinfo->aa_set)) + return -EINVAL; + } else if (!MBEDTLS_OID_CMP_RAW(MBEDTLS_OID_PKCS9_SIGNINGTIME, inner_p, + len)) { + mbedtls_x509_time st; + + inner_p += len; + ret = mbedtls_asn1_get_tag(&inner_p, p + seq_len, &len, + MBEDTLS_ASN1_CONSTRUCTED | + MBEDTLS_ASN1_SET); + if (ret) + return ret; + + ret = mbedtls_x509_get_time(&inner_p, p + seq_len, &st); + if (ret) + return ret; + sinfo->signing_time = x509_get_timestamp(&st); + + if (__test_and_set_bit(sinfo_has_signing_time, &sinfo->aa_set)) + return -EINVAL; + } else if (!MBEDTLS_OID_CMP_RAW(MBEDTLS_OID_PKCS9_SMIMECAP, inner_p, + len)) { + if (__test_and_set_bit(sinfo_has_smime_caps, &sinfo->aa_set)) + return -EINVAL; + + if (msg->data_type != OID_msIndirectData && + msg->data_type != OID_data) + return -EINVAL; + } else if (!MBEDTLS_OID_CMP_RAW(MBEDTLS_OID_MICROSOFT_SPOPUSINFO, inner_p, + len)) { + if (__test_and_set_bit(sinfo_has_ms_opus_info, &sinfo->aa_set)) + return -EINVAL; + } else if (!MBEDTLS_OID_CMP_RAW(MBEDTLS_OID_MICROSOFT_STATETYPE, inner_p, + len)) { + if (__test_and_set_bit(sinfo_has_ms_statement_type, &sinfo->aa_set)) + return -EINVAL; + } + + p += seq_len; + } + + if (ret && ret != MBEDTLS_ERR_ASN1_OUT_OF_DATA) + return ret; + + msg->have_authattrs = true; + + /* + * Skip the leading tag byte (MBEDTLS_ASN1_CONTEXT_SPECIFIC | + * MBEDTLS_ASN1_CONSTRUCTED) to satisfy pkcs7_digest() when calculating + * the digest of authattrs. + */ + sinfo->authattrs = aa + 1; + sinfo->authattrs_len = aa_len - 1; + + return 0; +} + +static int x509_populate_content_data(struct pkcs7_message *msg, + mbedtls_pkcs7 *pkcs7_ctx) +{ + struct pkcs7_mbedtls_ctx *mctx; + + if (!pkcs7_ctx->content_data.data || + !pkcs7_ctx->content_data.data_len) + return 0; + + mctx = kzalloc(sizeof(*mctx), GFP_KERNEL); + if (!mctx) + return -ENOMEM; + + mctx->content_data = kmemdup(pkcs7_ctx->content_data.data, + pkcs7_ctx->content_data.data_len, + GFP_KERNEL); + if (!mctx->content_data) { + pkcs7_free_mbedtls_ctx(mctx); + return -ENOMEM; + } + + msg->data = mctx->content_data; + msg->data_len = pkcs7_ctx->content_data.data_len; + msg->data_hdrlen = pkcs7_ctx->content_data.data_hdrlen; + msg->data_type = pkcs7_ctx->content_data.data_type; + + msg->mbedtls_ctx = mctx; + return 0; +} + +static int x509_populate_sinfo(struct pkcs7_message *msg, + mbedtls_pkcs7_signer_info *mb_sinfo, + struct pkcs7_signed_info **sinfo) +{ + struct pkcs7_signed_info *signed_info; + struct public_key_signature *s; + mbedtls_md_type_t md_alg; + struct pkcs7_sinfo_mbedtls_ctx *mctx; + int ret; + + signed_info = kzalloc(sizeof(*signed_info), GFP_KERNEL); + if (!signed_info) + return -ENOMEM; + + s = kzalloc(sizeof(*s), GFP_KERNEL); + if (!s) { + ret = -ENOMEM; + goto out_no_sig; + } + + mctx = kzalloc(sizeof(*mctx), GFP_KERNEL); + if (!mctx) { + ret = -ENOMEM; + goto out_no_mctx; + } + + /* + * Hash algorithm: + * + * alg_identifier = digestAlgorithm (DigestAlgorithmIdentifier) + * MbedTLS internally checks this field to ensure + * it is the same as digest_alg_identifiers. + * sig_alg_identifier = digestEncryptionAlgorithm + * (DigestEncryptionAlgorithmIdentifier) + * MbedTLS just saves this field without any actions. + * See function pkcs7_get_signer_info() for reference. + * + * Public key algorithm: + * No information related to public key algorithm under MbedTLS signer + * info. Assume that we are using RSA. + */ + ret = mbedtls_oid_get_md_alg(&mb_sinfo->alg_identifier, &md_alg); + if (ret) + goto out_err_sinfo; + s->pkey_algo = "rsa"; + + /* Translate the hash algorithm */ + switch (md_alg) { + case MBEDTLS_MD_SHA1: + s->hash_algo = "sha1"; + s->digest_size = SHA1_SUM_LEN; + break; + case MBEDTLS_MD_SHA256: + s->hash_algo = "sha256"; + s->digest_size = SHA256_SUM_LEN; + break; + case MBEDTLS_MD_SHA384: + s->hash_algo = "sha384"; + s->digest_size = SHA384_SUM_LEN; + break; + case MBEDTLS_MD_SHA512: + s->hash_algo = "sha512"; + s->digest_size = SHA512_SUM_LEN; + break; + /* Unsupported algo */ + case MBEDTLS_MD_MD5: + case MBEDTLS_MD_SHA224: + default: + ret = -EINVAL; + goto out_err_sinfo; + } + + /* + * auth_ids holds AuthorityKeyIdentifier, aka akid + * auth_ids[0]: + * [PKCS#7 or CMS ver 1] - generated from "Issuer + Serial number" + * [CMS ver 3] - generated from skid (subjectKeyId) + * auth_ids[1]: generated from skid (subjectKeyId) + * + * Assume that we are using PKCS#7 (msg->version=1), + * not CMS ver 3 (msg->version=3). + */ + s->auth_ids[0] = asymmetric_key_generate_id(mb_sinfo->serial.p, + mb_sinfo->serial.len, + mb_sinfo->issuer_raw.p, + mb_sinfo->issuer_raw.len); + if (!s->auth_ids[0]) { + ret = -ENOMEM; + goto out_err_sinfo; + } + + /* skip s->auth_ids[1], no subjectKeyId in MbedTLS signer info ctx */ + + /* + * Encoding can be pkcs1 or raw, but only pkcs1 is supported. + * Set the encoding explicitly to pkcs1. + */ + s->encoding = "pkcs1"; + + /* Copy the signature data */ + s->s = kmemdup(mb_sinfo->sig.p, mb_sinfo->sig.len, GFP_KERNEL); + if (!s->s) { + ret = -ENOMEM; + goto out_err_sinfo; + } + s->s_size = mb_sinfo->sig.len; + signed_info->sig = s; + + /* Save the Authenticate Attributes data if exists */ + if (!mb_sinfo->authattrs.data || !mb_sinfo->authattrs.data_len) + goto no_authattrs; + + mctx->authattrs_data = kmemdup(mb_sinfo->authattrs.data, + mb_sinfo->authattrs.data_len, + GFP_KERNEL); + if (!mctx->authattrs_data) { + ret = -ENOMEM; + goto out_err_sinfo; + } + signed_info->mbedtls_ctx = mctx; + + /* If authattrs exists, decode it and parse msgdigest from it */ + ret = authattrs_parse(msg, mctx->authattrs_data, + mb_sinfo->authattrs.data_len, + signed_info); + if (ret) + goto out_err_sinfo; + +no_authattrs: + *sinfo = signed_info; + return 0; + +out_err_sinfo: + pkcs7_free_sinfo_mbedtls_ctx(mctx); +out_no_mctx: + public_key_signature_free(s); +out_no_sig: + kfree(signed_info); + return ret; +} + +#endif /* CONFIG_IS_ENABLED(MBEDTLS_LIB_X509) */ + /* * Free a signed information block. */ @@ -59,6 +407,9 @@ static void pkcs7_free_signed_info(struct pkcs7_signed_info *sinfo) { if (sinfo) { public_key_signature_free(sinfo->sig); +#if CONFIG_IS_ENABLED(MBEDTLS_LIB_X509) + pkcs7_free_sinfo_mbedtls_ctx(sinfo->mbedtls_ctx); +#endif kfree(sinfo); } } @@ -88,11 +439,85 @@ void pkcs7_free_message(struct pkcs7_message *pkcs7) pkcs7->signed_infos = sinfo->next; pkcs7_free_signed_info(sinfo); } +#if CONFIG_IS_ENABLED(MBEDTLS_LIB_X509) + pkcs7_free_mbedtls_ctx(pkcs7->mbedtls_ctx); +#endif kfree(pkcs7); } } EXPORT_SYMBOL_GPL(pkcs7_free_message); +#if CONFIG_IS_ENABLED(MBEDTLS_LIB_X509) +struct pkcs7_message *pkcs7_parse_message(const void *data, size_t datalen) +{ + int i; + int ret; + mbedtls_pkcs7 pkcs7_ctx; + mbedtls_pkcs7_signer_info *mb_sinfos; + mbedtls_x509_crt *mb_certs; + struct pkcs7_message *msg; + struct x509_certificate **cert; + struct pkcs7_signed_info **sinfos; + + msg = kzalloc(sizeof(*msg), GFP_KERNEL); + if (!msg) { + ret = -ENOMEM; + goto out_no_msg; + } + + /* Parse the DER encoded PKCS#7 message using MbedTLS */ + mbedtls_pkcs7_init(&pkcs7_ctx); + ret = mbedtls_pkcs7_parse_der(&pkcs7_ctx, data, datalen); + /* Check if it is a PKCS#7 message with signed data */ + if (ret != MBEDTLS_PKCS7_SIGNED_DATA) + goto parse_fail; + + /* Assume that we are using PKCS#7, not CMS ver 3 */ + msg->version = 1; /* 1 for [PKCS#7 or CMS ver 1] */ + + /* Populate the certs to msg->certs */ + for (i = 0, cert = &msg->certs, mb_certs = &pkcs7_ctx.signed_data.certs; + i < pkcs7_ctx.signed_data.no_of_certs && mb_certs; + i++, cert = &(*cert)->next, mb_certs = mb_certs->next) { + ret = x509_populate_cert(mb_certs, cert); + if (ret) + goto parse_fail; + + (*cert)->index = i + 1; + } + + /* + * Skip populating crl, that is not currently in-use. + */ + + /* Populate content data */ + ret = x509_populate_content_data(msg, &pkcs7_ctx); + if (ret) + goto parse_fail; + + /* Populate signed info to msg->signed_infos */ + for (i = 0, sinfos = &msg->signed_infos, + mb_sinfos = &pkcs7_ctx.signed_data.signers; + i < pkcs7_ctx.signed_data.no_of_signers && mb_sinfos; + i++, sinfos = &(*sinfos)->next, mb_sinfos = mb_sinfos->next) { + ret = x509_populate_sinfo(msg, mb_sinfos, sinfos); + if (ret) + goto parse_fail; + + (*sinfos)->index = i + 1; + } + + mbedtls_pkcs7_free(&pkcs7_ctx); + return msg; + +parse_fail: + mbedtls_pkcs7_free(&pkcs7_ctx); + pkcs7_free_message(msg); +out_no_msg: + msg = ERR_PTR(ret); + return msg; +} +#else /* !CONFIG_IS_ENABLED(MBEDTLS_LIB_X509) */ /* * Check authenticatedAttributes are provided or not provided consistently. */ @@ -182,34 +607,6 @@ struct pkcs7_message *pkcs7_parse_message(const void *data, size_t datalen) } EXPORT_SYMBOL_GPL(pkcs7_parse_message); -/** - * pkcs7_get_content_data - Get access to the PKCS#7 content - * @pkcs7: The preparsed PKCS#7 message to access - * @_data: Place to return a pointer to the data - * @_data_len: Place to return the data length - * @_headerlen: Size of ASN.1 header not included in _data - * - * Get access to the data content of the PKCS#7 message. The size of the - * header of the ASN.1 object that contains it is also provided and can be used - * to adjust *_data and *_data_len to get the entire object. - * - * Returns -ENODATA if the data object was missing from the message. - */ -int pkcs7_get_content_data(const struct pkcs7_message *pkcs7, - const void **_data, size_t *_data_len, - size_t *_headerlen) -{ - if (!pkcs7->data) - return -ENODATA; - - *_data = pkcs7->data; - *_data_len = pkcs7->data_len; - if (_headerlen) - *_headerlen = pkcs7->data_hdrlen; - return 0; -} -EXPORT_SYMBOL_GPL(pkcs7_get_content_data); - /* * Note an OID when we find one for later processing when we know how * to interpret it. @@ -698,3 +1095,32 @@ int pkcs7_note_signed_info(void *context, size_t hdrlen, return -ENOMEM; return 0; } +#endif /* CONFIG_IS_ENABLED(MBEDTLS_LIB_X509) */ + +/** + * pkcs7_get_content_data - Get access to the PKCS#7 content + * @pkcs7: The preparsed PKCS#7 message to access + * @_data: Place to return a pointer to the data + * @_data_len: Place to return the data length + * @_headerlen: Size of ASN.1 header not included in _data + * + * Get access to the data content of the PKCS#7 message. The size of the + * header of the ASN.1 object that contains it is also provided and can be used + * to adjust *_data and *_data_len to get the entire object. + * + * Returns -ENODATA if the data object was missing from the message. + */ +int pkcs7_get_content_data(const struct pkcs7_message *pkcs7, + const void **_data, size_t *_data_len, + size_t *_headerlen) +{ + if (!pkcs7->data) + return -ENODATA; + + *_data = pkcs7->data; + *_data_len = pkcs7->data_len; + if (_headerlen) + *_headerlen = pkcs7->data_hdrlen; + return 0; +} +EXPORT_SYMBOL_GPL(pkcs7_get_content_data);