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Unified Diff: crypto/hmac_win.cc

Issue 6805019: Move crypto files out of base, to a top level directory. (Closed) Base URL: svn://svn.chromium.org/chrome/trunk/src/
Patch Set: Fixes comments by eroman Created 9 years, 8 months ago
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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
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