59 lines
1.6 KiB
C++
59 lines
1.6 KiB
C++
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "crypto/hmac.h"
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#include <stddef.h>
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#include <algorithm>
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#include "base/logging.h"
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#include "crypto/secure_util.h"
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#include "crypto/symmetric_key.h"
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namespace crypto {
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bool HMAC::Init(SymmetricKey* key) {
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std::string raw_key;
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bool result = key->GetRawKey(&raw_key) && Init(raw_key);
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// Zero out key copy. This might get optimized away, but one can hope.
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// Using std::string to store key info at all is a larger problem.
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std::fill(raw_key.begin(), raw_key.end(), 0);
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return result;
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}
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size_t HMAC::DigestLength() const {
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switch (hash_alg_) {
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case SHA1:
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return 20;
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case SHA256:
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return 32;
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default:
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NOTREACHED();
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return 0;
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}
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}
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bool HMAC::Verify(const base::StringPiece& data,
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const base::StringPiece& digest) const {
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if (digest.size() != DigestLength())
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return false;
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return VerifyTruncated(data, digest);
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}
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bool HMAC::VerifyTruncated(const base::StringPiece& data,
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const base::StringPiece& digest) const {
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if (digest.empty())
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return false;
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size_t digest_length = DigestLength();
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std::unique_ptr<unsigned char[]> computed_digest(
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new unsigned char[digest_length]);
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if (!Sign(data, computed_digest.get(), digest_length))
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return false;
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return SecureMemEqual(digest.data(), computed_digest.get(),
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std::min(digest.size(), digest_length));
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}
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} // namespace crypto
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