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1 // Copyright (c) 2011 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #include "crypto/signature_verifier.h" | |
6 | |
7 #include "base/logging.h" | |
8 #include "crypto/capi_util.h" | |
9 | |
10 #pragma comment(lib, "crypt32.lib") | |
11 | |
12 namespace crypto { | |
13 | |
14 SignatureVerifier::SignatureVerifier() : hash_object_(0), public_key_(0) { | |
15 if (!CryptAcquireContext(provider_.receive(), NULL, NULL, | |
16 PROV_RSA_FULL, CRYPT_VERIFYCONTEXT)) | |
17 provider_.reset(); | |
18 } | |
19 | |
20 SignatureVerifier::~SignatureVerifier() { | |
21 } | |
22 | |
23 bool SignatureVerifier::VerifyInit(const uint8* signature_algorithm, | |
24 int signature_algorithm_len, | |
25 const uint8* signature, | |
26 int signature_len, | |
27 const uint8* public_key_info, | |
28 int public_key_info_len) { | |
29 signature_.reserve(signature_len); | |
30 // CryptoAPI uses big integers in the little-endian byte order, so we need | |
31 // to first swap the order of signature bytes. | |
32 for (int i = signature_len - 1; i >= 0; --i) | |
33 signature_.push_back(signature[i]); | |
34 | |
35 CRYPT_DECODE_PARA decode_para; | |
36 decode_para.cbSize = sizeof(decode_para); | |
37 decode_para.pfnAlloc = crypto::CryptAlloc; | |
38 decode_para.pfnFree = crypto::CryptFree; | |
39 CERT_PUBLIC_KEY_INFO* cert_public_key_info = NULL; | |
40 DWORD struct_len = 0; | |
41 BOOL ok; | |
42 ok = CryptDecodeObjectEx(X509_ASN_ENCODING | PKCS_7_ASN_ENCODING, | |
43 X509_PUBLIC_KEY_INFO, | |
44 public_key_info, | |
45 public_key_info_len, | |
46 CRYPT_DECODE_ALLOC_FLAG | CRYPT_DECODE_NOCOPY_FLAG, | |
47 &decode_para, | |
48 &cert_public_key_info, | |
49 &struct_len); | |
50 if (!ok) | |
51 return false; | |
52 | |
53 ok = CryptImportPublicKeyInfo(provider_, | |
54 X509_ASN_ENCODING | PKCS_7_ASN_ENCODING, | |
55 cert_public_key_info, public_key_.receive()); | |
56 crypto::CryptFree(cert_public_key_info); | |
57 if (!ok) | |
58 return false; | |
59 | |
60 CRYPT_ALGORITHM_IDENTIFIER* signature_algorithm_id; | |
61 struct_len = 0; | |
62 ok = CryptDecodeObjectEx(X509_ASN_ENCODING | PKCS_7_ASN_ENCODING, | |
63 X509_ALGORITHM_IDENTIFIER, | |
64 signature_algorithm, | |
65 signature_algorithm_len, | |
66 CRYPT_DECODE_ALLOC_FLAG | CRYPT_DECODE_NOCOPY_FLAG, | |
67 &decode_para, | |
68 &signature_algorithm_id, | |
69 &struct_len); | |
70 DCHECK(ok || GetLastError() == ERROR_FILE_NOT_FOUND); | |
71 ALG_ID hash_alg_id; | |
72 if (ok) { | |
73 hash_alg_id = CALG_MD4; // Initialize to a weak hash algorithm that we | |
74 // don't support. | |
75 if (!strcmp(signature_algorithm_id->pszObjId, szOID_RSA_SHA1RSA)) | |
76 hash_alg_id = CALG_SHA1; | |
77 else if (!strcmp(signature_algorithm_id->pszObjId, szOID_RSA_MD5RSA)) | |
78 hash_alg_id = CALG_MD5; | |
79 crypto::CryptFree(signature_algorithm_id); | |
80 DCHECK_NE(static_cast<ALG_ID>(CALG_MD4), hash_alg_id); | |
81 if (hash_alg_id == CALG_MD4) | |
82 return false; // Unsupported hash algorithm. | |
83 } else if (GetLastError() == ERROR_FILE_NOT_FOUND) { | |
84 // TODO(wtc): X509_ALGORITHM_IDENTIFIER isn't supported on XP SP2. We | |
85 // may be able to encapsulate signature_algorithm in a dummy SignedContent | |
86 // and decode it with X509_CERT into a CERT_SIGNED_CONTENT_INFO. For now, | |
87 // just hardcode the hash algorithm to be SHA-1. | |
88 hash_alg_id = CALG_SHA1; | |
89 } else { | |
90 return false; | |
91 } | |
92 | |
93 ok = CryptCreateHash(provider_, hash_alg_id, 0, 0, hash_object_.receive()); | |
94 if (!ok) | |
95 return false; | |
96 return true; | |
97 } | |
98 | |
99 void SignatureVerifier::VerifyUpdate(const uint8* data_part, | |
100 int data_part_len) { | |
101 BOOL ok = CryptHashData(hash_object_, data_part, data_part_len, 0); | |
102 DCHECK(ok) << "CryptHashData failed: " << GetLastError(); | |
103 } | |
104 | |
105 bool SignatureVerifier::VerifyFinal() { | |
106 BOOL ok = CryptVerifySignature(hash_object_, &signature_[0], | |
107 signature_.size(), public_key_, NULL, 0); | |
108 Reset(); | |
109 if (!ok) | |
110 return false; | |
111 return true; | |
112 } | |
113 | |
114 void SignatureVerifier::Reset() { | |
115 hash_object_.reset(); | |
116 public_key_.reset(); | |
117 signature_.clear(); | |
118 } | |
119 | |
120 } // namespace crypto | |
121 | |
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