| // Copyright (c) 2013 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 "quic/core/crypto/aead_base_decrypter.h" |
| |
| #include <cstdint> |
| #include <string> |
| |
| #include "absl/base/macros.h" |
| #include "absl/strings/string_view.h" |
| #include "third_party/boringssl/src/include/openssl/crypto.h" |
| #include "third_party/boringssl/src/include/openssl/err.h" |
| #include "third_party/boringssl/src/include/openssl/evp.h" |
| #include "quic/core/quic_utils.h" |
| #include "quic/platform/api/quic_bug_tracker.h" |
| #include "quic/platform/api/quic_logging.h" |
| |
| namespace quic { |
| |
| namespace { |
| |
| // Clear OpenSSL error stack. |
| void ClearOpenSslErrors() { |
| while (ERR_get_error()) { |
| } |
| } |
| |
| // In debug builds only, log OpenSSL error stack. Then clear OpenSSL error |
| // stack. |
| void DLogOpenSslErrors() { |
| #ifdef NDEBUG |
| ClearOpenSslErrors(); |
| #else |
| while (uint32_t error = ERR_get_error()) { |
| char buf[120]; |
| ERR_error_string_n(error, buf, ABSL_ARRAYSIZE(buf)); |
| QUIC_DLOG(ERROR) << "OpenSSL error: " << buf; |
| } |
| #endif |
| } |
| |
| const EVP_AEAD* InitAndCall(const EVP_AEAD* (*aead_getter)()) { |
| // Ensure BoringSSL is initialized before calling |aead_getter|. In Chromium, |
| // the static initializer is disabled. |
| CRYPTO_library_init(); |
| return aead_getter(); |
| } |
| |
| } // namespace |
| |
| AeadBaseDecrypter::AeadBaseDecrypter(const EVP_AEAD* (*aead_getter)(), |
| size_t key_size, |
| size_t auth_tag_size, |
| size_t nonce_size, |
| bool use_ietf_nonce_construction) |
| : aead_alg_(InitAndCall(aead_getter)), |
| key_size_(key_size), |
| auth_tag_size_(auth_tag_size), |
| nonce_size_(nonce_size), |
| use_ietf_nonce_construction_(use_ietf_nonce_construction), |
| have_preliminary_key_(false) { |
| DCHECK_GT(256u, key_size); |
| DCHECK_GT(256u, auth_tag_size); |
| DCHECK_GT(256u, nonce_size); |
| DCHECK_LE(key_size_, sizeof(key_)); |
| DCHECK_LE(nonce_size_, sizeof(iv_)); |
| } |
| |
| AeadBaseDecrypter::~AeadBaseDecrypter() {} |
| |
| bool AeadBaseDecrypter::SetKey(absl::string_view key) { |
| DCHECK_EQ(key.size(), key_size_); |
| if (key.size() != key_size_) { |
| return false; |
| } |
| memcpy(key_, key.data(), key.size()); |
| |
| EVP_AEAD_CTX_cleanup(ctx_.get()); |
| if (!EVP_AEAD_CTX_init(ctx_.get(), aead_alg_, key_, key_size_, auth_tag_size_, |
| nullptr)) { |
| DLogOpenSslErrors(); |
| return false; |
| } |
| |
| return true; |
| } |
| |
| bool AeadBaseDecrypter::SetNoncePrefix(absl::string_view nonce_prefix) { |
| if (use_ietf_nonce_construction_) { |
| QUIC_BUG << "Attempted to set nonce prefix on IETF QUIC crypter"; |
| return false; |
| } |
| DCHECK_EQ(nonce_prefix.size(), nonce_size_ - sizeof(QuicPacketNumber)); |
| if (nonce_prefix.size() != nonce_size_ - sizeof(QuicPacketNumber)) { |
| return false; |
| } |
| memcpy(iv_, nonce_prefix.data(), nonce_prefix.size()); |
| return true; |
| } |
| |
| bool AeadBaseDecrypter::SetIV(absl::string_view iv) { |
| if (!use_ietf_nonce_construction_) { |
| QUIC_BUG << "Attempted to set IV on Google QUIC crypter"; |
| return false; |
| } |
| DCHECK_EQ(iv.size(), nonce_size_); |
| if (iv.size() != nonce_size_) { |
| return false; |
| } |
| memcpy(iv_, iv.data(), iv.size()); |
| return true; |
| } |
| |
| bool AeadBaseDecrypter::SetPreliminaryKey(absl::string_view key) { |
| DCHECK(!have_preliminary_key_); |
| SetKey(key); |
| have_preliminary_key_ = true; |
| |
| return true; |
| } |
| |
| bool AeadBaseDecrypter::SetDiversificationNonce( |
| const DiversificationNonce& nonce) { |
| if (!have_preliminary_key_) { |
| return true; |
| } |
| |
| std::string key, nonce_prefix; |
| size_t prefix_size = nonce_size_; |
| if (!use_ietf_nonce_construction_) { |
| prefix_size -= sizeof(QuicPacketNumber); |
| } |
| DiversifyPreliminaryKey( |
| absl::string_view(reinterpret_cast<const char*>(key_), key_size_), |
| absl::string_view(reinterpret_cast<const char*>(iv_), prefix_size), nonce, |
| key_size_, prefix_size, &key, &nonce_prefix); |
| |
| if (!SetKey(key) || |
| (!use_ietf_nonce_construction_ && !SetNoncePrefix(nonce_prefix)) || |
| (use_ietf_nonce_construction_ && !SetIV(nonce_prefix))) { |
| DCHECK(false); |
| return false; |
| } |
| |
| have_preliminary_key_ = false; |
| return true; |
| } |
| |
| bool AeadBaseDecrypter::DecryptPacket(uint64_t packet_number, |
| absl::string_view associated_data, |
| absl::string_view ciphertext, |
| char* output, |
| size_t* output_length, |
| size_t max_output_length) { |
| if (ciphertext.length() < auth_tag_size_) { |
| return false; |
| } |
| |
| if (have_preliminary_key_) { |
| QUIC_BUG << "Unable to decrypt while key diversification is pending"; |
| return false; |
| } |
| |
| uint8_t nonce[kMaxNonceSize]; |
| memcpy(nonce, iv_, nonce_size_); |
| size_t prefix_len = nonce_size_ - sizeof(packet_number); |
| if (use_ietf_nonce_construction_) { |
| for (size_t i = 0; i < sizeof(packet_number); ++i) { |
| nonce[prefix_len + i] ^= |
| (packet_number >> ((sizeof(packet_number) - i - 1) * 8)) & 0xff; |
| } |
| } else { |
| memcpy(nonce + prefix_len, &packet_number, sizeof(packet_number)); |
| } |
| if (!EVP_AEAD_CTX_open( |
| ctx_.get(), reinterpret_cast<uint8_t*>(output), output_length, |
| max_output_length, reinterpret_cast<const uint8_t*>(nonce), |
| nonce_size_, reinterpret_cast<const uint8_t*>(ciphertext.data()), |
| ciphertext.size(), |
| reinterpret_cast<const uint8_t*>(associated_data.data()), |
| associated_data.size())) { |
| // Because QuicFramer does trial decryption, decryption errors are expected |
| // when encryption level changes. So we don't log decryption errors. |
| ClearOpenSslErrors(); |
| return false; |
| } |
| return true; |
| } |
| |
| size_t AeadBaseDecrypter::GetKeySize() const { |
| return key_size_; |
| } |
| |
| size_t AeadBaseDecrypter::GetNoncePrefixSize() const { |
| return nonce_size_ - sizeof(QuicPacketNumber); |
| } |
| |
| size_t AeadBaseDecrypter::GetIVSize() const { |
| return nonce_size_; |
| } |
| |
| absl::string_view AeadBaseDecrypter::GetKey() const { |
| return absl::string_view(reinterpret_cast<const char*>(key_), key_size_); |
| } |
| |
| absl::string_view AeadBaseDecrypter::GetNoncePrefix() const { |
| return absl::string_view(reinterpret_cast<const char*>(iv_), |
| nonce_size_ - sizeof(QuicPacketNumber)); |
| } |
| |
| } // namespace quic |