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1 // Copyright 2014 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 <openssl/aes.h> | |
6 #include <openssl/evp.h> | |
7 | |
8 #include "base/logging.h" | |
9 #include "base/numerics/safe_math.h" | |
10 #include "base/stl_util.h" | |
11 #include "components/webcrypto/crypto_data.h" | |
12 #include "components/webcrypto/openssl/aes_algorithm_openssl.h" | |
13 #include "components/webcrypto/openssl/key_openssl.h" | |
14 #include "components/webcrypto/openssl/util_openssl.h" | |
15 #include "components/webcrypto/status.h" | |
16 #include "components/webcrypto/webcrypto_util.h" | |
17 #include "crypto/openssl_util.h" | |
18 #include "crypto/scoped_openssl_types.h" | |
19 #include "third_party/WebKit/public/platform/WebCryptoAlgorithmParams.h" | |
20 | |
21 namespace webcrypto { | |
22 | |
23 namespace { | |
24 | |
25 const EVP_CIPHER* GetAESCipherByKeyLength(size_t key_length_bytes) { | |
26 // BoringSSL does not support 192-bit AES keys. | |
27 switch (key_length_bytes) { | |
28 case 16: | |
29 return EVP_aes_128_cbc(); | |
30 case 32: | |
31 return EVP_aes_256_cbc(); | |
32 default: | |
33 return NULL; | |
34 } | |
35 } | |
36 | |
37 Status AesCbcEncryptDecrypt(EncryptOrDecrypt cipher_operation, | |
38 const blink::WebCryptoAlgorithm& algorithm, | |
39 const blink::WebCryptoKey& key, | |
40 const CryptoData& data, | |
41 std::vector<uint8_t>* buffer) { | |
42 crypto::OpenSSLErrStackTracer err_tracer(FROM_HERE); | |
43 | |
44 const blink::WebCryptoAesCbcParams* params = algorithm.aesCbcParams(); | |
45 const std::vector<uint8_t>& raw_key = | |
46 SymKeyOpenSsl::Cast(key)->raw_key_data(); | |
47 | |
48 if (params->iv().size() != 16) | |
49 return Status::ErrorIncorrectSizeAesCbcIv(); | |
50 | |
51 // According to the openssl docs, the amount of data written may be as large | |
52 // as (data_size + cipher_block_size - 1), constrained to a multiple of | |
53 // cipher_block_size. | |
54 base::CheckedNumeric<int> output_max_len = data.byte_length(); | |
55 output_max_len += AES_BLOCK_SIZE - 1; | |
56 if (!output_max_len.IsValid()) | |
57 return Status::ErrorDataTooLarge(); | |
58 | |
59 const unsigned remainder = output_max_len.ValueOrDie() % AES_BLOCK_SIZE; | |
60 if (remainder != 0) | |
61 output_max_len += AES_BLOCK_SIZE - remainder; | |
62 if (!output_max_len.IsValid()) | |
63 return Status::ErrorDataTooLarge(); | |
64 | |
65 // Note: PKCS padding is enabled by default | |
66 crypto::ScopedOpenSSL<EVP_CIPHER_CTX, EVP_CIPHER_CTX_free> context( | |
67 EVP_CIPHER_CTX_new()); | |
68 | |
69 if (!context.get()) | |
70 return Status::OperationError(); | |
71 | |
72 const EVP_CIPHER* const cipher = GetAESCipherByKeyLength(raw_key.size()); | |
73 DCHECK(cipher); | |
74 | |
75 if (!EVP_CipherInit_ex(context.get(), cipher, NULL, &raw_key[0], | |
76 params->iv().data(), cipher_operation)) { | |
77 return Status::OperationError(); | |
78 } | |
79 | |
80 buffer->resize(output_max_len.ValueOrDie()); | |
81 | |
82 unsigned char* const buffer_data = vector_as_array(buffer); | |
83 | |
84 int output_len = 0; | |
85 if (!EVP_CipherUpdate(context.get(), buffer_data, &output_len, data.bytes(), | |
86 data.byte_length())) { | |
87 return Status::OperationError(); | |
88 } | |
89 int final_output_chunk_len = 0; | |
90 if (!EVP_CipherFinal_ex(context.get(), buffer_data + output_len, | |
91 &final_output_chunk_len)) { | |
92 return Status::OperationError(); | |
93 } | |
94 | |
95 const unsigned int final_output_len = | |
96 static_cast<unsigned int>(output_len) + | |
97 static_cast<unsigned int>(final_output_chunk_len); | |
98 | |
99 buffer->resize(final_output_len); | |
100 | |
101 return Status::Success(); | |
102 } | |
103 | |
104 class AesCbcImplementation : public AesAlgorithm { | |
105 public: | |
106 AesCbcImplementation() : AesAlgorithm("CBC") {} | |
107 | |
108 Status Encrypt(const blink::WebCryptoAlgorithm& algorithm, | |
109 const blink::WebCryptoKey& key, | |
110 const CryptoData& data, | |
111 std::vector<uint8_t>* buffer) const override { | |
112 return AesCbcEncryptDecrypt(ENCRYPT, algorithm, key, data, buffer); | |
113 } | |
114 | |
115 Status Decrypt(const blink::WebCryptoAlgorithm& algorithm, | |
116 const blink::WebCryptoKey& key, | |
117 const CryptoData& data, | |
118 std::vector<uint8_t>* buffer) const override { | |
119 return AesCbcEncryptDecrypt(DECRYPT, algorithm, key, data, buffer); | |
120 } | |
121 }; | |
122 | |
123 } // namespace | |
124 | |
125 AlgorithmImplementation* CreatePlatformAesCbcImplementation() { | |
126 return new AesCbcImplementation; | |
127 } | |
128 | |
129 } // namespace webcrypto | |
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