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// 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 "net/third_party/quiche/src/quic/core/crypto/crypto_utils.h"
#include <memory>
#include <string>
#include "third_party/boringssl/src/include/openssl/bytestring.h"
#include "third_party/boringssl/src/include/openssl/hkdf.h"
#include "third_party/boringssl/src/include/openssl/sha.h"
#include "net/third_party/quiche/src/quic/core/crypto/aes_128_gcm_decrypter.h"
#include "net/third_party/quiche/src/quic/core/crypto/aes_128_gcm_encrypter.h"
#include "net/third_party/quiche/src/quic/core/crypto/crypto_handshake.h"
#include "net/third_party/quiche/src/quic/core/crypto/crypto_protocol.h"
#include "net/third_party/quiche/src/quic/core/crypto/quic_decrypter.h"
#include "net/third_party/quiche/src/quic/core/crypto/quic_encrypter.h"
#include "net/third_party/quiche/src/quic/core/crypto/quic_hkdf.h"
#include "net/third_party/quiche/src/quic/core/crypto/quic_random.h"
#include "net/third_party/quiche/src/quic/core/quic_data_writer.h"
#include "net/third_party/quiche/src/quic/core/quic_time.h"
#include "net/third_party/quiche/src/quic/core/quic_utils.h"
#include "net/third_party/quiche/src/quic/platform/api/quic_arraysize.h"
#include "net/third_party/quiche/src/quic/platform/api/quic_bug_tracker.h"
#include "net/third_party/quiche/src/quic/platform/api/quic_logging.h"
#include "net/third_party/quiche/src/quic/platform/api/quic_ptr_util.h"
#include "net/third_party/quiche/src/quic/platform/api/quic_str_cat.h"
namespace quic {
// TODO(nharper): HkdfExpandLabel and SetKeyAndIV (below) implement what is
// specified in draft-ietf-quic-tls-16. The latest editors' draft has changed
// derivation again, and this will need to be updated to reflect those (and any
// other future) changes.
// static
std::vector<uint8_t> CryptoUtils::HkdfExpandLabel(
const EVP_MD* prf,
const std::vector<uint8_t>& secret,
const std::string& label,
size_t out_len) {
bssl::ScopedCBB quic_hkdf_label;
CBB inner_label;
const char label_prefix[] = "tls13 ";
// 19 = size(u16) + size(u8) + len("tls13 ") + len ("client in") + size(u8)
static const size_t max_quic_hkdf_label_length = 19;
if (!CBB_init(quic_hkdf_label.get(), max_quic_hkdf_label_length) ||
!CBB_add_u16(quic_hkdf_label.get(), out_len) ||
!CBB_add_u8_length_prefixed(quic_hkdf_label.get(), &inner_label) ||
!CBB_add_bytes(&inner_label,
reinterpret_cast<const uint8_t*>(label_prefix),
QUIC_ARRAYSIZE(label_prefix) - 1) ||
!CBB_add_bytes(&inner_label,
reinterpret_cast<const uint8_t*>(label.data()),
label.size()) ||
!CBB_add_u8(quic_hkdf_label.get(), 0) ||
!CBB_flush(quic_hkdf_label.get())) {
QUIC_LOG(ERROR) << "Building HKDF label failed";
return std::vector<uint8_t>();
}
std::vector<uint8_t> out;
out.resize(out_len);
if (!HKDF_expand(out.data(), out_len, prf, secret.data(), secret.size(),
CBB_data(quic_hkdf_label.get()),
CBB_len(quic_hkdf_label.get()))) {
QUIC_LOG(ERROR) << "Running HKDF-Expand-Label failed";
return std::vector<uint8_t>();
}
return out;
}
void CryptoUtils::SetKeyAndIV(const EVP_MD* prf,
const std::vector<uint8_t>& pp_secret,
QuicCrypter* crypter) {
std::vector<uint8_t> key = CryptoUtils::HkdfExpandLabel(
prf, pp_secret, "quic key", crypter->GetKeySize());
std::vector<uint8_t> iv = CryptoUtils::HkdfExpandLabel(
prf, pp_secret, "quic iv", crypter->GetIVSize());
std::vector<uint8_t> pn = CryptoUtils::HkdfExpandLabel(
prf, pp_secret, "quic hp", crypter->GetKeySize());
crypter->SetKey(
QuicStringPiece(reinterpret_cast<char*>(key.data()), key.size()));
crypter->SetIV(
QuicStringPiece(reinterpret_cast<char*>(iv.data()), iv.size()));
crypter->SetHeaderProtectionKey(
QuicStringPiece(reinterpret_cast<char*>(pn.data()), pn.size()));
}
namespace {
const uint8_t kInitialSalt[] = {0x7f, 0xbc, 0xdb, 0x0e, 0x7c, 0x66, 0xbb,
0xe9, 0x19, 0x3a, 0x96, 0xcd, 0x21, 0x51,
0x9e, 0xbd, 0x7a, 0x02, 0x64, 0x4a};
const char kPreSharedKeyLabel[] = "QUIC PSK";
} // namespace
// static
void CryptoUtils::CreateTlsInitialCrypters(Perspective perspective,
QuicTransportVersion version,
QuicConnectionId connection_id,
CrypterPair* crypters) {
QUIC_DLOG(INFO) << "Creating "
<< (perspective == Perspective::IS_CLIENT ? "client"
: "server")
<< " TLS crypters for " << connection_id;
QUIC_BUG_IF(!QuicUtils::IsConnectionIdValidForVersion(connection_id, version))
<< "CreateTlsInitialCrypters: attempted to use connection ID "
<< connection_id << " which is invalid with version "
<< QuicVersionToString(version);
const EVP_MD* hash = EVP_sha256();
std::vector<uint8_t> handshake_secret;
handshake_secret.resize(EVP_MAX_MD_SIZE);
size_t handshake_secret_len;
const bool hkdf_extract_success = HKDF_extract(
handshake_secret.data(), &handshake_secret_len, hash,
reinterpret_cast<const uint8_t*>(connection_id.data()),
connection_id.length(), kInitialSalt, QUIC_ARRAYSIZE(kInitialSalt));
QUIC_BUG_IF(!hkdf_extract_success)
<< "HKDF_extract failed when creating initial crypters";
handshake_secret.resize(handshake_secret_len);
const std::string client_label = "client in";
const std::string server_label = "server in";
std::string encryption_label, decryption_label;
if (perspective == Perspective::IS_CLIENT) {
encryption_label = client_label;
decryption_label = server_label;
} else {
encryption_label = server_label;
decryption_label = client_label;
}
crypters->encrypter = QuicMakeUnique<Aes128GcmEncrypter>();
std::vector<uint8_t> encryption_secret = HkdfExpandLabel(
hash, handshake_secret, encryption_label, EVP_MD_size(hash));
SetKeyAndIV(hash, encryption_secret, crypters->encrypter.get());
crypters->decrypter = QuicMakeUnique<Aes128GcmDecrypter>();
std::vector<uint8_t> decryption_secret = HkdfExpandLabel(
hash, handshake_secret, decryption_label, EVP_MD_size(hash));
SetKeyAndIV(hash, decryption_secret, crypters->decrypter.get());
}
// static
void CryptoUtils::GenerateNonce(QuicWallTime now,
QuicRandom* random_generator,
QuicStringPiece orbit,
std::string* nonce) {
// a 4-byte timestamp + 28 random bytes.
nonce->reserve(kNonceSize);
nonce->resize(kNonceSize);
uint32_t gmt_unix_time = static_cast<uint32_t>(now.ToUNIXSeconds());
// The time in the nonce must be encoded in big-endian because the
// strike-register depends on the nonces being ordered by time.
(*nonce)[0] = static_cast<char>(gmt_unix_time >> 24);
(*nonce)[1] = static_cast<char>(gmt_unix_time >> 16);
(*nonce)[2] = static_cast<char>(gmt_unix_time >> 8);
(*nonce)[3] = static_cast<char>(gmt_unix_time);
size_t bytes_written = 4;
if (orbit.size() == 8) {
memcpy(&(*nonce)[bytes_written], orbit.data(), orbit.size());
bytes_written += orbit.size();
}
random_generator->RandBytes(&(*nonce)[bytes_written],
kNonceSize - bytes_written);
}
// static
bool CryptoUtils::DeriveKeys(QuicStringPiece premaster_secret,
QuicTag aead,
QuicStringPiece client_nonce,
QuicStringPiece server_nonce,
QuicStringPiece pre_shared_key,
const std::string& hkdf_input,
Perspective perspective,
Diversification diversification,
CrypterPair* crypters,
std::string* subkey_secret) {
// If the connection is using PSK, concatenate it with the pre-master secret.
std::unique_ptr<char[]> psk_premaster_secret;
if (!pre_shared_key.empty()) {
const QuicStringPiece label(kPreSharedKeyLabel);
const size_t psk_premaster_secret_size = label.size() + 1 +
pre_shared_key.size() + 8 +
premaster_secret.size() + 8;
psk_premaster_secret = QuicMakeUnique<char[]>(psk_premaster_secret_size);
QuicDataWriter writer(psk_premaster_secret_size, psk_premaster_secret.get(),
HOST_BYTE_ORDER);
if (!writer.WriteStringPiece(label) || !writer.WriteUInt8(0) ||
!writer.WriteStringPiece(pre_shared_key) ||
!writer.WriteUInt64(pre_shared_key.size()) ||
!writer.WriteStringPiece(premaster_secret) ||
!writer.WriteUInt64(premaster_secret.size()) ||
writer.remaining() != 0) {
return false;
}
premaster_secret =
QuicStringPiece(psk_premaster_secret.get(), psk_premaster_secret_size);
}
crypters->encrypter = QuicEncrypter::Create(aead);
crypters->decrypter = QuicDecrypter::Create(aead);
size_t key_bytes = crypters->encrypter->GetKeySize();
size_t nonce_prefix_bytes = crypters->encrypter->GetNoncePrefixSize();
size_t subkey_secret_bytes =
subkey_secret == nullptr ? 0 : premaster_secret.length();
QuicStringPiece nonce = client_nonce;
std::string nonce_storage;
if (!server_nonce.empty()) {
nonce_storage = std::string(client_nonce) + std::string(server_nonce);
nonce = nonce_storage;
}
QuicHKDF hkdf(premaster_secret, nonce, hkdf_input, key_bytes,
nonce_prefix_bytes, subkey_secret_bytes);
// Key derivation depends on the key diversification method being employed.
// both the client and the server support never doing key diversification.
// The server also supports immediate diversification, and the client
// supports pending diversification.
switch (diversification.mode()) {
case Diversification::NEVER: {
if (perspective == Perspective::IS_SERVER) {
if (!crypters->encrypter->SetKey(hkdf.server_write_key()) ||
!crypters->encrypter->SetNoncePrefix(hkdf.server_write_iv()) ||
!crypters->encrypter->SetHeaderProtectionKey(
hkdf.server_hp_key()) ||
!crypters->decrypter->SetKey(hkdf.client_write_key()) ||
!crypters->decrypter->SetNoncePrefix(hkdf.client_write_iv()) ||
!crypters->decrypter->SetHeaderProtectionKey(
hkdf.client_hp_key())) {
return false;
}
} else {
if (!crypters->encrypter->SetKey(hkdf.client_write_key()) ||
!crypters->encrypter->SetNoncePrefix(hkdf.client_write_iv()) ||
!crypters->encrypter->SetHeaderProtectionKey(
hkdf.client_hp_key()) ||
!crypters->decrypter->SetKey(hkdf.server_write_key()) ||
!crypters->decrypter->SetNoncePrefix(hkdf.server_write_iv()) ||
!crypters->decrypter->SetHeaderProtectionKey(
hkdf.server_hp_key())) {
return false;
}
}
break;
}
case Diversification::PENDING: {
if (perspective == Perspective::IS_SERVER) {
QUIC_BUG << "Pending diversification is only for clients.";
return false;
}
if (!crypters->encrypter->SetKey(hkdf.client_write_key()) ||
!crypters->encrypter->SetNoncePrefix(hkdf.client_write_iv()) ||
!crypters->encrypter->SetHeaderProtectionKey(hkdf.client_hp_key()) ||
!crypters->decrypter->SetPreliminaryKey(hkdf.server_write_key()) ||
!crypters->decrypter->SetNoncePrefix(hkdf.server_write_iv()) ||
!crypters->decrypter->SetHeaderProtectionKey(hkdf.server_hp_key())) {
return false;
}
break;
}
case Diversification::NOW: {
if (perspective == Perspective::IS_CLIENT) {
QUIC_BUG << "Immediate diversification is only for servers.";
return false;
}
std::string key, nonce_prefix;
QuicDecrypter::DiversifyPreliminaryKey(
hkdf.server_write_key(), hkdf.server_write_iv(),
*diversification.nonce(), key_bytes, nonce_prefix_bytes, &key,
&nonce_prefix);
if (!crypters->decrypter->SetKey(hkdf.client_write_key()) ||
!crypters->decrypter->SetNoncePrefix(hkdf.client_write_iv()) ||
!crypters->decrypter->SetHeaderProtectionKey(hkdf.client_hp_key()) ||
!crypters->encrypter->SetKey(key) ||
!crypters->encrypter->SetNoncePrefix(nonce_prefix) ||
!crypters->encrypter->SetHeaderProtectionKey(hkdf.server_hp_key())) {
return false;
}
break;
}
default:
DCHECK(false);
}
if (subkey_secret != nullptr) {
*subkey_secret = std::string(hkdf.subkey_secret());
}
return true;
}
// static
bool CryptoUtils::ExportKeyingMaterial(QuicStringPiece subkey_secret,
QuicStringPiece label,
QuicStringPiece context,
size_t result_len,
std::string* result) {
for (size_t i = 0; i < label.length(); i++) {
if (label[i] == '\0') {
QUIC_LOG(ERROR) << "ExportKeyingMaterial label may not contain NULs";
return false;
}
}
// Create HKDF info input: null-terminated label + length-prefixed context
if (context.length() >= std::numeric_limits<uint32_t>::max()) {
QUIC_LOG(ERROR) << "Context value longer than 2^32";
return false;
}
uint32_t context_length = static_cast<uint32_t>(context.length());
std::string info = std::string(label);
info.push_back('\0');
info.append(reinterpret_cast<char*>(&context_length), sizeof(context_length));
info.append(context.data(), context.length());
QuicHKDF hkdf(subkey_secret, QuicStringPiece() /* no salt */, info,
result_len, 0 /* no fixed IV */, 0 /* no subkey secret */);
*result = std::string(hkdf.client_write_key());
return true;
}
// static
uint64_t CryptoUtils::ComputeLeafCertHash(QuicStringPiece cert) {
return QuicUtils::FNV1a_64_Hash(cert);
}
QuicErrorCode CryptoUtils::ValidateServerHello(
const CryptoHandshakeMessage& server_hello,
const ParsedQuicVersionVector& negotiated_versions,
std::string* error_details) {
DCHECK(error_details != nullptr);
if (server_hello.tag() != kSHLO) {
*error_details = "Bad tag";
return QUIC_INVALID_CRYPTO_MESSAGE_TYPE;
}
QuicVersionLabelVector supported_version_labels;
if (server_hello.GetVersionLabelList(kVER, &supported_version_labels) !=
QUIC_NO_ERROR) {
*error_details = "server hello missing version list";
return QUIC_INVALID_CRYPTO_MESSAGE_PARAMETER;
}
return ValidateServerHelloVersions(supported_version_labels,
negotiated_versions, error_details);
}
QuicErrorCode CryptoUtils::ValidateServerHelloVersions(
const QuicVersionLabelVector& server_versions,
const ParsedQuicVersionVector& negotiated_versions,
std::string* error_details) {
if (!negotiated_versions.empty()) {
bool mismatch = server_versions.size() != negotiated_versions.size();
for (size_t i = 0; i < server_versions.size() && !mismatch; ++i) {
mismatch =
server_versions[i] != CreateQuicVersionLabel(negotiated_versions[i]);
}
// The server sent a list of supported versions, and the connection
// reports that there was a version negotiation during the handshake.
// Ensure that these two lists are identical.
if (mismatch) {
*error_details = QuicStrCat(
"Downgrade attack detected: ServerVersions(", server_versions.size(),
")[", QuicVersionLabelVectorToString(server_versions, ",", 30),
"] NegotiatedVersions(", negotiated_versions.size(), ")[",
ParsedQuicVersionVectorToString(negotiated_versions, ",", 30), "]");
return QUIC_VERSION_NEGOTIATION_MISMATCH;
}
}
return QUIC_NO_ERROR;
}
QuicErrorCode CryptoUtils::ValidateClientHello(
const CryptoHandshakeMessage& client_hello,
ParsedQuicVersion version,
const ParsedQuicVersionVector& supported_versions,
std::string* error_details) {
if (client_hello.tag() != kCHLO) {
*error_details = "Bad tag";
return QUIC_INVALID_CRYPTO_MESSAGE_TYPE;
}
// If the client's preferred version is not the version we are currently
// speaking, then the client went through a version negotiation. In this
// case, we need to make sure that we actually do not support this version
// and that it wasn't a downgrade attack.
QuicVersionLabel client_version_label;
if (client_hello.GetVersionLabel(kVER, &client_version_label) !=
QUIC_NO_ERROR) {
*error_details = "client hello missing version list";
return QUIC_INVALID_CRYPTO_MESSAGE_PARAMETER;
}
return ValidateClientHelloVersion(client_version_label, version,
supported_versions, error_details);
}
QuicErrorCode CryptoUtils::ValidateClientHelloVersion(
QuicVersionLabel client_version,
ParsedQuicVersion connection_version,
const ParsedQuicVersionVector& supported_versions,
std::string* error_details) {
if (client_version != CreateQuicVersionLabel(connection_version)) {
// Check to see if |client_version| is actually on the supported versions
// list. If not, the server doesn't support that version and it's not a
// downgrade attack.
for (size_t i = 0; i < supported_versions.size(); ++i) {
if (client_version == CreateQuicVersionLabel(supported_versions[i])) {
*error_details = QuicStrCat(
"Downgrade attack detected: ClientVersion[",
QuicVersionLabelToString(client_version), "] SupportedVersions(",
supported_versions.size(), ")[",
ParsedQuicVersionVectorToString(supported_versions, ",", 30), "]");
return QUIC_VERSION_NEGOTIATION_MISMATCH;
}
}
}
return QUIC_NO_ERROR;
}
#define RETURN_STRING_LITERAL(x) \
case x: \
return #x
// Returns the name of the HandshakeFailureReason as a char*
// static
const char* CryptoUtils::HandshakeFailureReasonToString(
HandshakeFailureReason reason) {
switch (reason) {
RETURN_STRING_LITERAL(HANDSHAKE_OK);
RETURN_STRING_LITERAL(CLIENT_NONCE_UNKNOWN_FAILURE);
RETURN_STRING_LITERAL(CLIENT_NONCE_INVALID_FAILURE);
RETURN_STRING_LITERAL(CLIENT_NONCE_NOT_UNIQUE_FAILURE);
RETURN_STRING_LITERAL(CLIENT_NONCE_INVALID_ORBIT_FAILURE);
RETURN_STRING_LITERAL(CLIENT_NONCE_INVALID_TIME_FAILURE);
RETURN_STRING_LITERAL(CLIENT_NONCE_STRIKE_REGISTER_TIMEOUT);
RETURN_STRING_LITERAL(CLIENT_NONCE_STRIKE_REGISTER_FAILURE);
RETURN_STRING_LITERAL(SERVER_NONCE_DECRYPTION_FAILURE);
RETURN_STRING_LITERAL(SERVER_NONCE_INVALID_FAILURE);
RETURN_STRING_LITERAL(SERVER_NONCE_NOT_UNIQUE_FAILURE);
RETURN_STRING_LITERAL(SERVER_NONCE_INVALID_TIME_FAILURE);
RETURN_STRING_LITERAL(SERVER_NONCE_REQUIRED_FAILURE);
RETURN_STRING_LITERAL(SERVER_CONFIG_INCHOATE_HELLO_FAILURE);
RETURN_STRING_LITERAL(SERVER_CONFIG_UNKNOWN_CONFIG_FAILURE);
RETURN_STRING_LITERAL(SOURCE_ADDRESS_TOKEN_INVALID_FAILURE);
RETURN_STRING_LITERAL(SOURCE_ADDRESS_TOKEN_DECRYPTION_FAILURE);
RETURN_STRING_LITERAL(SOURCE_ADDRESS_TOKEN_PARSE_FAILURE);
RETURN_STRING_LITERAL(SOURCE_ADDRESS_TOKEN_DIFFERENT_IP_ADDRESS_FAILURE);
RETURN_STRING_LITERAL(SOURCE_ADDRESS_TOKEN_CLOCK_SKEW_FAILURE);
RETURN_STRING_LITERAL(SOURCE_ADDRESS_TOKEN_EXPIRED_FAILURE);
RETURN_STRING_LITERAL(INVALID_EXPECTED_LEAF_CERTIFICATE);
RETURN_STRING_LITERAL(MAX_FAILURE_REASON);
}
// Return a default value so that we return this when |reason| doesn't match
// any HandshakeFailureReason.. This can happen when the message by the peer
// (attacker) has invalid reason.
return "INVALID_HANDSHAKE_FAILURE_REASON";
}
// static
std::string CryptoUtils::HashHandshakeMessage(
const CryptoHandshakeMessage& message,
Perspective /*perspective*/) {
std::string output;
const QuicData& serialized = message.GetSerialized();
uint8_t digest[SHA256_DIGEST_LENGTH];
SHA256(reinterpret_cast<const uint8_t*>(serialized.data()),
serialized.length(), digest);
output.assign(reinterpret_cast<const char*>(digest), sizeof(digest));
return output;
}
#undef RETURN_STRING_LITERAL // undef for jumbo builds
} // namespace quic