From d93f05b21d04eab7ed1a289c7731163641be8dc6 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 1 Jul 2014 16:02:52 +0100 Subject: pefile: Parse the "Microsoft individual code signing" data blob The PKCS#7 certificate should contain a "Microsoft individual code signing" data blob as its signed content. This blob contains a digest of the signed content of the PE binary and the OID of the digest algorithm used (typically SHA256). Signed-off-by: David Howells Acked-by: Vivek Goyal Reviewed-by: Kees Cook --- crypto/asymmetric_keys/mscode_parser.c | 120 +++++++++++++++++++++++++++++++++ 1 file changed, 120 insertions(+) create mode 100644 crypto/asymmetric_keys/mscode_parser.c (limited to 'crypto/asymmetric_keys/mscode_parser.c') diff --git a/crypto/asymmetric_keys/mscode_parser.c b/crypto/asymmetric_keys/mscode_parser.c new file mode 100644 index 00000000..09336c32 --- /dev/null +++ b/crypto/asymmetric_keys/mscode_parser.c @@ -0,0 +1,120 @@ +/* Parse a Microsoft Individual Code Signing blob + * + * Copyright (C) 2014 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#define pr_fmt(fmt) "MSCODE: "fmt +#include +#include +#include +#include +#include +#include "verify_pefile.h" +#include "mscode-asn1.h" + +/* + * Parse a Microsoft Individual Code Signing blob + */ +int mscode_parse(struct pefile_context *ctx) +{ + const void *content_data; + size_t data_len; + int ret; + + ret = pkcs7_get_content_data(ctx->pkcs7, &content_data, &data_len, 1); + + if (ret) { + pr_debug("PKCS#7 message does not contain data\n"); + return ret; + } + + pr_devel("Data: %zu [%*ph]\n", data_len, (unsigned)(data_len), + content_data); + + return asn1_ber_decoder(&mscode_decoder, ctx, content_data, data_len); +} + +/* + * Check the content type OID + */ +int mscode_note_content_type(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + enum OID oid; + + oid = look_up_OID(value, vlen); + if (oid == OID__NR) { + char buffer[50]; + + sprint_oid(value, vlen, buffer, sizeof(buffer)); + pr_err("Unknown OID: %s\n", buffer); + return -EBADMSG; + } + + if (oid != OID_msIndividualSPKeyPurpose) { + pr_err("Unexpected content type OID %u\n", oid); + return -EBADMSG; + } + + return 0; +} + +/* + * Note the digest algorithm OID + */ +int mscode_note_digest_algo(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct pefile_context *ctx = context; + char buffer[50]; + enum OID oid; + + oid = look_up_OID(value, vlen); + switch (oid) { + case OID_md4: + ctx->digest_algo = HASH_ALGO_MD4; + break; + case OID_md5: + ctx->digest_algo = HASH_ALGO_MD5; + break; + case OID_sha1: + ctx->digest_algo = HASH_ALGO_SHA1; + break; + case OID_sha256: + ctx->digest_algo = HASH_ALGO_SHA256; + break; + + case OID__NR: + sprint_oid(value, vlen, buffer, sizeof(buffer)); + pr_err("Unknown OID: %s\n", buffer); + return -EBADMSG; + + default: + pr_err("Unsupported content type: %u\n", oid); + return -ENOPKG; + } + + return 0; +} + +/* + * Note the digest we're guaranteeing with this certificate + */ +int mscode_note_digest(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct pefile_context *ctx = context; + + ctx->digest = value; + ctx->digest_len = vlen; + return 0; +} -- cgit v1.2.3 From 8e1561e67b44b9439e02336dabfeb903040a7392 Mon Sep 17 00:00:00 2001 From: Vivek Goyal Date: Tue, 8 Jul 2014 18:10:46 +0100 Subject: pefile: Handle pesign using the wrong OID The pesign utility had a bug where it was using OID_msIndividualSPKeyPurpose instead of OID_msPeImageDataObjId - so allow both OIDs. Signed-off-by: Vivek Goyal Acked-by: Vivek Goyal --- crypto/asymmetric_keys/mscode_parser.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'crypto/asymmetric_keys/mscode_parser.c') diff --git a/crypto/asymmetric_keys/mscode_parser.c b/crypto/asymmetric_keys/mscode_parser.c index 09336c32..214a9921 100644 --- a/crypto/asymmetric_keys/mscode_parser.c +++ b/crypto/asymmetric_keys/mscode_parser.c @@ -58,7 +58,13 @@ int mscode_note_content_type(void *context, size_t hdrlen, return -EBADMSG; } - if (oid != OID_msIndividualSPKeyPurpose) { + /* + * pesign utility had a bug where it was putting + * OID_msIndividualSPKeyPurpose instead of OID_msPeImageDataObjId + * So allow both OIDs. + */ + if (oid != OID_msPeImageDataObjId && + oid != OID_msIndividualSPKeyPurpose) { pr_err("Unexpected content type OID %u\n", oid); return -EBADMSG; } -- cgit v1.2.3