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// Copyright 2014 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 "net/quic/crypto/chacha20_poly1305_decrypter.h"
#include "net/quic/quic_flags.h"
#include "net/quic/test_tools/quic_test_utils.h"
using base::StringPiece;
using std::string;
namespace {
// The test vectors come from draft-agl-tls-chacha20poly1305-04 Section 7.
// Each test vector consists of six strings of lowercase hexadecimal digits.
// The strings may be empty (zero length). A test vector with a nullptr |key|
// marks the end of an array of test vectors.
struct TestVector {
// Input:
const char* key;
const char* iv;
const char* aad;
const char* ct;
// Expected output:
const char* pt; // An empty string "" means decryption succeeded and
// the plaintext is zero-length. NULL means decryption
// failed.
};
const TestVector test_vectors[] = {
{"4290bcb154173531f314af57f3be3b5006da371ece272afa1b5dbdd110"
"0a1007",
"cd7cf67be39c794a", "87e229d4500845a079c0",
"e3e446f7ede9a19b62a4677dabf4e3d24b876bb28475", // "3896e1d6" truncated.
"86d09974840bded2a5ca"},
// Modify the ciphertext (ChaCha20 encryption output).
{
"4290bcb154173531f314af57f3be3b5006da371ece272afa1b5dbdd110"
"0a1007",
"cd7cf67be39c794a", "87e229d4500845a079c0",
"f3e446f7ede9a19b62a4677dabf4e3d24b876bb28475", // "3896e1d6"
// truncated.
nullptr // FAIL
},
// Modify the ciphertext (Poly1305 authenticator).
{
"4290bcb154173531f314af57f3be3b5006da371ece272afa1b5dbdd110"
"0a1007",
"cd7cf67be39c794a", "87e229d4500845a079c0",
"e3e446f7ede9a19b62a4677dabf4e3d24b876bb28476", // "3896e1d6"
// truncated.
nullptr // FAIL
},
// Modify the associated data.
{
"4290bcb154173531f314af57f3be3b5006da371ece272afa1b5dbdd110"
"0a1007",
"dd7cf67be39c794a", "87e229d4500845a079c0",
"e3e446f7ede9a19b62a4677dabf4e3d24b876bb28475", // "3896e1d6"
// truncated.
nullptr // FAIL
},
{nullptr}};
} // namespace
namespace net {
namespace test {
// DecryptWithNonce wraps the |Decrypt| method of |decrypter| to allow passing
// in an nonce and also to allocate the buffer needed for the plaintext.
QuicData* DecryptWithNonce(ChaCha20Poly1305Decrypter* decrypter,
StringPiece nonce,
StringPiece associated_data,
StringPiece ciphertext) {
QuicPathId path_id = kDefaultPathId;
QuicPacketNumber packet_number;
StringPiece nonce_prefix(nonce.data(), nonce.size() - sizeof(packet_number));
decrypter->SetNoncePrefix(nonce_prefix);
memcpy(&packet_number, nonce.data() + nonce_prefix.size(),
sizeof(packet_number));
path_id = static_cast<QuicPathId>(
packet_number >> 8 * (sizeof(packet_number) - sizeof(path_id)));
packet_number &= UINT64_C(0x00FFFFFFFFFFFFFF);
scoped_ptr<char[]> output(new char[ciphertext.length()]);
size_t output_length = 0;
const bool success = decrypter->DecryptPacket(
path_id, packet_number, associated_data, ciphertext, output.get(),
&output_length, ciphertext.length());
if (!success) {
return nullptr;
}
return new QuicData(output.release(), output_length, true);
}
TEST(ChaCha20Poly1305DecrypterTest, Decrypt) {
for (size_t i = 0; test_vectors[i].key != nullptr; i++) {
// If not present then decryption is expected to fail.
bool has_pt = test_vectors[i].pt;
// Decode the test vector.
string key;
string iv;
string aad;
string ct;
string pt;
ASSERT_TRUE(DecodeHexString(test_vectors[i].key, &key));
ASSERT_TRUE(DecodeHexString(test_vectors[i].iv, &iv));
ASSERT_TRUE(DecodeHexString(test_vectors[i].aad, &aad));
ASSERT_TRUE(DecodeHexString(test_vectors[i].ct, &ct));
if (has_pt) {
ASSERT_TRUE(DecodeHexString(test_vectors[i].pt, &pt));
}
ChaCha20Poly1305Decrypter decrypter;
ASSERT_TRUE(decrypter.SetKey(key));
scoped_ptr<QuicData> decrypted(DecryptWithNonce(
&decrypter, iv,
// This deliberately tests that the decrypter can handle an AAD that
// is set to nullptr, as opposed to a zero-length, non-nullptr pointer.
StringPiece(aad.length() ? aad.data() : nullptr, aad.length()), ct));
if (!decrypted.get()) {
EXPECT_FALSE(has_pt);
continue;
}
EXPECT_TRUE(has_pt);
ASSERT_EQ(pt.length(), decrypted->length());
test::CompareCharArraysWithHexError("plaintext", decrypted->data(),
pt.length(), pt.data(), pt.length());
}
}
} // namespace test
} // namespace net
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