1 // SPDX-License-Identifier: GPL-2.0+
3 * MSCode parser using MbedTLS ASN1 library
5 * Copyright (c) 2024 Linaro Limited
9 #include <linux/kernel.h>
10 #include <linux/err.h>
11 #include <crypto/pkcs7.h>
12 #include <crypto/mscode.h>
15 * Parse a Microsoft Individual Code Signing blob
18 * U.P.OBJECTIDENTIFIER 1.3.6.1.4.1.311.2.1.15 (SPC_PE_IMAGE_DATA_OBJID)
20 * U.P.BITSTRING NaN : 0 unused bit(s);
23 * [C.P.0] <arbitrary string>
30 * U.P.OBJECTIDENTIFIER <digest algorithm OID>
33 * U.P.OCTETSTRING <PE image digest>
36 * @ctx: PE file context.
37 * @content_data: content data pointer.
38 * @data_len: content data length.
39 * @asn1hdrlen: ASN1 header length.
41 int mscode_parse(void *ctx, const void *content_data, size_t data_len,
44 struct pefile_context *_ctx = ctx;
45 unsigned char *p = (unsigned char *)content_data;
46 unsigned char *end = (unsigned char *)content_data + data_len;
49 unsigned char *inner_p;
52 ret = mbedtls_asn1_get_tag(&p, end, &seq_len,
53 MBEDTLS_ASN1_CONSTRUCTED |
54 MBEDTLS_ASN1_SEQUENCE);
59 ret = mbedtls_asn1_get_tag(&inner_p, inner_p + seq_len, &len,
64 /* Sanity check on the PE Image Data OID (1.3.6.1.4.1.311.2.1.15) */
65 if (MBEDTLS_OID_CMP_RAW(MBEDTLS_OID_MICROSOFT_PEIMAGEDATA, inner_p,
70 ret = mbedtls_asn1_get_tag(&p, end, &seq_len,
71 MBEDTLS_ASN1_CONSTRUCTED |
72 MBEDTLS_ASN1_SEQUENCE);
76 ret = mbedtls_asn1_get_tag(&p, p + seq_len, &seq_len,
77 MBEDTLS_ASN1_CONSTRUCTED |
78 MBEDTLS_ASN1_SEQUENCE);
85 * Check if the inner sequence contains a supported hash
88 ret = mbedtls_asn1_get_tag(&inner_p, inner_p + seq_len, &len,
93 if (!MBEDTLS_OID_CMP_RAW(MBEDTLS_OID_DIGEST_ALG_MD5, inner_p, len))
94 _ctx->digest_algo = "md5";
95 else if (!MBEDTLS_OID_CMP_RAW(MBEDTLS_OID_DIGEST_ALG_SHA1, inner_p,
97 _ctx->digest_algo = "sha1";
98 else if (!MBEDTLS_OID_CMP_RAW(MBEDTLS_OID_DIGEST_ALG_SHA224, inner_p,
100 _ctx->digest_algo = "sha224";
101 else if (!MBEDTLS_OID_CMP_RAW(MBEDTLS_OID_DIGEST_ALG_SHA256, inner_p,
103 _ctx->digest_algo = "sha256";
104 else if (!MBEDTLS_OID_CMP_RAW(MBEDTLS_OID_DIGEST_ALG_SHA384, inner_p,
106 _ctx->digest_algo = "sha384";
107 else if (!MBEDTLS_OID_CMP_RAW(MBEDTLS_OID_DIGEST_ALG_SHA512, inner_p,
109 _ctx->digest_algo = "sha512";
111 if (!_ctx->digest_algo)
115 ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_OCTET_STRING);
120 _ctx->digest_len = len;