Index: crypto/hmac_win.cc |
=================================================================== |
--- crypto/hmac_win.cc (revision 0) |
+++ crypto/hmac_win.cc (revision 0) |
@@ -0,0 +1,197 @@ |
+// Copyright (c) 2011 The Chromium Authors. All rights reserved. |
+// Use of this source code is governed by a BSD-style license that can be |
+// found in the LICENSE file. |
+ |
+#include "crypto/hmac.h" |
+ |
+#include <windows.h> |
+#include <wincrypt.h> |
+ |
+#include <algorithm> |
+#include <vector> |
+ |
+#include "base/logging.h" |
+#include "crypto/scoped_capi_types.h" |
+#include "crypto/third_party/nss/blapi.h" |
+#include "crypto/third_party/nss/sha256.h" |
+ |
+namespace crypto { |
+ |
+namespace { |
+ |
+// Implementation of HMAC-SHA-256: |
+// |
+// SHA-256 is supported in Windows XP SP3 or later. We still need to support |
+// Windows XP SP2, so unfortunately we have to implement HMAC-SHA-256 here. |
+ |
+enum { |
+ SHA256_BLOCK_SIZE = 64 // Block size (in bytes) of the input to SHA-256. |
+}; |
+ |
+// See FIPS 198: The Keyed-Hash Message Authentication Code (HMAC). |
+void ComputeHMACSHA256(const unsigned char* key, size_t key_len, |
+ const unsigned char* text, size_t text_len, |
+ unsigned char* output, size_t output_len) { |
+ SHA256Context ctx; |
+ |
+ // Pre-process the key, if necessary. |
+ unsigned char key0[SHA256_BLOCK_SIZE]; |
+ if (key_len > SHA256_BLOCK_SIZE) { |
+ SHA256_Begin(&ctx); |
+ SHA256_Update(&ctx, key, key_len); |
+ SHA256_End(&ctx, key0, NULL, SHA256_LENGTH); |
+ memset(key0 + SHA256_LENGTH, 0, SHA256_BLOCK_SIZE - SHA256_LENGTH); |
+ } else { |
+ memcpy(key0, key, key_len); |
+ memset(key0 + key_len, 0, SHA256_BLOCK_SIZE - key_len); |
+ } |
+ |
+ unsigned char padded_key[SHA256_BLOCK_SIZE]; |
+ unsigned char inner_hash[SHA256_LENGTH]; |
+ |
+ // XOR key0 with ipad. |
+ for (int i = 0; i < SHA256_BLOCK_SIZE; ++i) |
+ padded_key[i] = key0[i] ^ 0x36; |
+ |
+ // Compute the inner hash. |
+ SHA256_Begin(&ctx); |
+ SHA256_Update(&ctx, padded_key, SHA256_BLOCK_SIZE); |
+ SHA256_Update(&ctx, text, text_len); |
+ SHA256_End(&ctx, inner_hash, NULL, SHA256_LENGTH); |
+ |
+ // XOR key0 with opad. |
+ for (int i = 0; i < SHA256_BLOCK_SIZE; ++i) |
+ padded_key[i] = key0[i] ^ 0x5c; |
+ |
+ // Compute the outer hash. |
+ SHA256_Begin(&ctx); |
+ SHA256_Update(&ctx, padded_key, SHA256_BLOCK_SIZE); |
+ SHA256_Update(&ctx, inner_hash, SHA256_LENGTH); |
+ SHA256_End(&ctx, output, NULL, output_len); |
+} |
+ |
+} // namespace |
+ |
+struct HMACPlatformData { |
+ ~HMACPlatformData() { |
+ if (!raw_key_.empty()) { |
+ SecureZeroMemory(&raw_key_[0], raw_key_.size()); |
+ } |
+ |
+ // Destroy the key before releasing the provider. |
+ key_.reset(); |
+ } |
+ |
+ ScopedHCRYPTPROV provider_; |
+ ScopedHCRYPTKEY key_; |
+ |
+ // For HMAC-SHA-256 only. |
+ std::vector<unsigned char> raw_key_; |
+}; |
+ |
+HMAC::HMAC(HashAlgorithm hash_alg) |
+ : hash_alg_(hash_alg), plat_(new HMACPlatformData()) { |
+ // Only SHA-1 and SHA-256 hash algorithms are supported now. |
+ DCHECK(hash_alg_ == SHA1 || hash_alg_ == SHA256); |
+} |
+ |
+bool HMAC::Init(const unsigned char* key, int key_length) { |
+ if (plat_->provider_ || plat_->key_ || !plat_->raw_key_.empty()) { |
+ // Init must not be called more than once on the same HMAC object. |
+ NOTREACHED(); |
+ return false; |
+ } |
+ |
+ if (hash_alg_ == SHA256) { |
+ if (key_length < SHA256_LENGTH / 2) |
+ return false; // Key is too short. |
+ plat_->raw_key_.assign(key, key + key_length); |
+ return true; |
+ } |
+ |
+ if (!CryptAcquireContext(plat_->provider_.receive(), NULL, NULL, |
+ PROV_RSA_FULL, CRYPT_VERIFYCONTEXT)) { |
+ NOTREACHED(); |
+ return false; |
+ } |
+ |
+ // This code doesn't work on Win2k because PLAINTEXTKEYBLOB and |
+ // CRYPT_IPSEC_HMAC_KEY are not supported on Windows 2000. PLAINTEXTKEYBLOB |
+ // allows the import of an unencrypted key. For Win2k support, a cubmbersome |
+ // exponent-of-one key procedure must be used: |
+ // http://support.microsoft.com/kb/228786/en-us |
+ // CRYPT_IPSEC_HMAC_KEY allows keys longer than 16 bytes. |
+ |
+ struct KeyBlob { |
+ BLOBHEADER header; |
+ DWORD key_size; |
+ BYTE key_data[1]; |
+ }; |
+ size_t key_blob_size = std::max(offsetof(KeyBlob, key_data) + key_length, |
+ sizeof(KeyBlob)); |
+ std::vector<BYTE> key_blob_storage = std::vector<BYTE>(key_blob_size); |
+ KeyBlob* key_blob = reinterpret_cast<KeyBlob*>(&key_blob_storage[0]); |
+ key_blob->header.bType = PLAINTEXTKEYBLOB; |
+ key_blob->header.bVersion = CUR_BLOB_VERSION; |
+ key_blob->header.reserved = 0; |
+ key_blob->header.aiKeyAlg = CALG_RC2; |
+ key_blob->key_size = key_length; |
+ memcpy(key_blob->key_data, key, key_length); |
+ |
+ if (!CryptImportKey(plat_->provider_, &key_blob_storage[0], |
+ key_blob_storage.size(), 0, CRYPT_IPSEC_HMAC_KEY, |
+ plat_->key_.receive())) { |
+ NOTREACHED(); |
+ return false; |
+ } |
+ |
+ // Destroy the copy of the key. |
+ SecureZeroMemory(key_blob->key_data, key_length); |
+ |
+ return true; |
+} |
+ |
+HMAC::~HMAC() { |
+} |
+ |
+bool HMAC::Sign(const std::string& data, |
+ unsigned char* digest, |
+ int digest_length) { |
+ if (hash_alg_ == SHA256) { |
+ if (plat_->raw_key_.empty()) |
+ return false; |
+ ComputeHMACSHA256(&plat_->raw_key_[0], plat_->raw_key_.size(), |
+ reinterpret_cast<const unsigned char*>(data.data()), |
+ data.size(), digest, digest_length); |
+ return true; |
+ } |
+ |
+ if (!plat_->provider_ || !plat_->key_) |
+ return false; |
+ |
+ if (hash_alg_ != SHA1) { |
+ NOTREACHED(); |
+ return false; |
+ } |
+ |
+ ScopedHCRYPTHASH hash; |
+ if (!CryptCreateHash(plat_->provider_, CALG_HMAC, plat_->key_, 0, |
+ hash.receive())) |
+ return false; |
+ |
+ HMAC_INFO hmac_info; |
+ memset(&hmac_info, 0, sizeof(hmac_info)); |
+ hmac_info.HashAlgid = CALG_SHA1; |
+ if (!CryptSetHashParam(hash, HP_HMAC_INFO, |
+ reinterpret_cast<BYTE*>(&hmac_info), 0)) |
+ return false; |
+ |
+ if (!CryptHashData(hash, reinterpret_cast<const BYTE*>(data.data()), |
+ static_cast<DWORD>(data.size()), 0)) |
+ return false; |
+ |
+ DWORD sha1_size = digest_length; |
+ return !!CryptGetHashParam(hash, HP_HASHVAL, digest, &sha1_size, 0); |
+} |
+ |
+} // namespace crypto |
Property changes on: crypto\hmac_win.cc |
___________________________________________________________________ |
Added: svn:eol-style |
+ LF |