1 /* Parse a Microsoft Individual Code Signing blob 2 * 3 * Copyright (C) 2014 Red Hat, Inc. All Rights Reserved. 4 * Written by David Howells (dhowells@redhat.com) 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public Licence 8 * as published by the Free Software Foundation; either version 9 * 2 of the Licence, or (at your option) any later version. 10 */ 11 12 #define pr_fmt(fmt) "MSCODE: "fmt 13 #include <linux/kernel.h> 14 #include <linux/slab.h> 15 #include <linux/err.h> 16 #include <linux/oid_registry.h> 17 #include <crypto/pkcs7.h> 18 #include "verify_pefile.h" 19 #include "mscode-asn1.h" 20 21 /* 22 * Parse a Microsoft Individual Code Signing blob 23 */ 24 int mscode_parse(void *_ctx, const void *content_data, size_t data_len, 25 size_t asn1hdrlen) 26 { 27 struct pefile_context *ctx = _ctx; 28 29 content_data -= asn1hdrlen; 30 data_len += asn1hdrlen; 31 pr_devel("Data: %zu [%*ph]\n", data_len, (unsigned)(data_len), 32 content_data); 33 34 return asn1_ber_decoder(&mscode_decoder, ctx, content_data, data_len); 35 } 36 37 /* 38 * Check the content type OID 39 */ 40 int mscode_note_content_type(void *context, size_t hdrlen, 41 unsigned char tag, 42 const void *value, size_t vlen) 43 { 44 enum OID oid; 45 46 oid = look_up_OID(value, vlen); 47 if (oid == OID__NR) { 48 char buffer[50]; 49 50 sprint_oid(value, vlen, buffer, sizeof(buffer)); 51 pr_err("Unknown OID: %s\n", buffer); 52 return -EBADMSG; 53 } 54 55 /* 56 * pesign utility had a bug where it was putting 57 * OID_msIndividualSPKeyPurpose instead of OID_msPeImageDataObjId 58 * So allow both OIDs. 59 */ 60 if (oid != OID_msPeImageDataObjId && 61 oid != OID_msIndividualSPKeyPurpose) { 62 pr_err("Unexpected content type OID %u\n", oid); 63 return -EBADMSG; 64 } 65 66 return 0; 67 } 68 69 /* 70 * Note the digest algorithm OID 71 */ 72 int mscode_note_digest_algo(void *context, size_t hdrlen, 73 unsigned char tag, 74 const void *value, size_t vlen) 75 { 76 struct pefile_context *ctx = context; 77 char buffer[50]; 78 enum OID oid; 79 80 oid = look_up_OID(value, vlen); 81 switch (oid) { 82 case OID_md4: 83 ctx->digest_algo = "md4"; 84 break; 85 case OID_md5: 86 ctx->digest_algo = "md5"; 87 break; 88 case OID_sha1: 89 ctx->digest_algo = "sha1"; 90 break; 91 case OID_sha256: 92 ctx->digest_algo = "sha256"; 93 break; 94 case OID_sha384: 95 ctx->digest_algo = "sha384"; 96 break; 97 case OID_sha512: 98 ctx->digest_algo = "sha512"; 99 break; 100 case OID_sha224: 101 ctx->digest_algo = "sha224"; 102 break; 103 104 case OID__NR: 105 sprint_oid(value, vlen, buffer, sizeof(buffer)); 106 pr_err("Unknown OID: %s\n", buffer); 107 return -EBADMSG; 108 109 default: 110 pr_err("Unsupported content type: %u\n", oid); 111 return -ENOPKG; 112 } 113 114 return 0; 115 } 116 117 /* 118 * Note the digest we're guaranteeing with this certificate 119 */ 120 int mscode_note_digest(void *context, size_t hdrlen, 121 unsigned char tag, 122 const void *value, size_t vlen) 123 { 124 struct pefile_context *ctx = context; 125 126 ctx->digest = kmemdup(value, vlen, GFP_KERNEL); 127 if (!ctx->digest) 128 return -ENOMEM; 129 130 ctx->digest_len = vlen; 131 132 return 0; 133 } 134