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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | 1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #include "crypto/hmac.h" | 5 #include "crypto/hmac.h" |
6 | 6 |
| 7 #include <openssl/hmac.h> |
7 #include <stddef.h> | 8 #include <stddef.h> |
8 | 9 |
9 #include <algorithm> | 10 #include <algorithm> |
10 #include <memory> | |
11 | 11 |
12 #include "base/logging.h" | 12 #include "base/logging.h" |
| 13 #include "base/stl_util.h" |
| 14 #include "crypto/openssl_util.h" |
13 #include "crypto/secure_util.h" | 15 #include "crypto/secure_util.h" |
14 #include "crypto/symmetric_key.h" | 16 #include "crypto/symmetric_key.h" |
15 | 17 |
16 namespace crypto { | 18 namespace crypto { |
17 | 19 |
18 bool HMAC::Init(SymmetricKey* key) { | 20 HMAC::HMAC(HashAlgorithm hash_alg) : hash_alg_(hash_alg), initialized_(false) { |
19 std::string raw_key; | 21 // Only SHA-1 and SHA-256 hash algorithms are supported now. |
20 bool result = key->GetRawKey(&raw_key) && Init(raw_key); | 22 DCHECK(hash_alg_ == SHA1 || hash_alg_ == SHA256); |
21 // Zero out key copy. This might get optimized away, but one can hope. | 23 } |
22 // Using std::string to store key info at all is a larger problem. | 24 |
23 std::fill(raw_key.begin(), raw_key.end(), 0); | 25 HMAC::~HMAC() { |
24 return result; | 26 // Zero out key copy. |
| 27 key_.assign(key_.size(), 0); |
| 28 STLClearObject(&key_); |
25 } | 29 } |
26 | 30 |
27 size_t HMAC::DigestLength() const { | 31 size_t HMAC::DigestLength() const { |
28 switch (hash_alg_) { | 32 switch (hash_alg_) { |
29 case SHA1: | 33 case SHA1: |
30 return 20; | 34 return 20; |
31 case SHA256: | 35 case SHA256: |
32 return 32; | 36 return 32; |
33 default: | 37 default: |
34 NOTREACHED(); | 38 NOTREACHED(); |
35 return 0; | 39 return 0; |
36 } | 40 } |
37 } | 41 } |
38 | 42 |
| 43 bool HMAC::Init(const unsigned char* key, size_t key_length) { |
| 44 // Init must not be called more than once on the same HMAC object. |
| 45 DCHECK(!initialized_); |
| 46 initialized_ = true; |
| 47 key_.assign(key, key + key_length); |
| 48 return true; |
| 49 } |
| 50 |
| 51 bool HMAC::Init(SymmetricKey* key) { |
| 52 std::string raw_key; |
| 53 bool result = key->GetRawKey(&raw_key) && Init(raw_key); |
| 54 // Zero out key copy. This might get optimized away, but one can hope. |
| 55 // Using std::string to store key info at all is a larger problem. |
| 56 std::fill(raw_key.begin(), raw_key.end(), 0); |
| 57 return result; |
| 58 } |
| 59 |
| 60 bool HMAC::Sign(const base::StringPiece& data, |
| 61 unsigned char* digest, |
| 62 size_t digest_length) const { |
| 63 DCHECK(initialized_); |
| 64 |
| 65 ScopedOpenSSLSafeSizeBuffer<EVP_MAX_MD_SIZE> result(digest, digest_length); |
| 66 return !!::HMAC(hash_alg_ == SHA1 ? EVP_sha1() : EVP_sha256(), |
| 67 key_.data(), key_.size(), |
| 68 reinterpret_cast<const unsigned char*>(data.data()), |
| 69 data.size(), result.safe_buffer(), NULL); |
| 70 } |
| 71 |
39 bool HMAC::Verify(const base::StringPiece& data, | 72 bool HMAC::Verify(const base::StringPiece& data, |
40 const base::StringPiece& digest) const { | 73 const base::StringPiece& digest) const { |
41 if (digest.size() != DigestLength()) | 74 if (digest.size() != DigestLength()) |
42 return false; | 75 return false; |
43 return VerifyTruncated(data, digest); | 76 return VerifyTruncated(data, digest); |
44 } | 77 } |
45 | 78 |
46 bool HMAC::VerifyTruncated(const base::StringPiece& data, | 79 bool HMAC::VerifyTruncated(const base::StringPiece& data, |
47 const base::StringPiece& digest) const { | 80 const base::StringPiece& digest) const { |
48 if (digest.empty()) | 81 if (digest.empty()) |
49 return false; | 82 return false; |
50 size_t digest_length = DigestLength(); | 83 size_t digest_length = DigestLength(); |
51 std::unique_ptr<unsigned char[]> computed_digest( | 84 std::unique_ptr<unsigned char[]> computed_digest( |
52 new unsigned char[digest_length]); | 85 new unsigned char[digest_length]); |
53 if (!Sign(data, computed_digest.get(), digest_length)) | 86 if (!Sign(data, computed_digest.get(), digest_length)) |
54 return false; | 87 return false; |
55 | 88 |
56 return SecureMemEqual(digest.data(), computed_digest.get(), | 89 return SecureMemEqual(digest.data(), computed_digest.get(), |
57 std::min(digest.size(), digest_length)); | 90 std::min(digest.size(), digest_length)); |
58 } | 91 } |
59 | 92 |
60 } // namespace crypto | 93 } // namespace crypto |
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