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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 "components/webcrypto/algorithms/aes.h"
- #include <stddef.h>
- #include "components/webcrypto/algorithms/secret_key_util.h"
- #include "components/webcrypto/algorithms/util.h"
- #include "components/webcrypto/blink_key_handle.h"
- #include "components/webcrypto/jwk.h"
- #include "components/webcrypto/status.h"
- #include "third_party/blink/public/platform/web_crypto_algorithm_params.h"
- #include "third_party/blink/public/platform/web_crypto_key_algorithm.h"
- namespace webcrypto {
- namespace {
- // Creates an AES algorithm name for the given key size (in bytes). For
- // instance "A128CBC" is the result of suffix="CBC", keylen_bytes=16.
- std::string MakeJwkAesAlgorithmName(const std::string& suffix,
- size_t keylen_bytes) {
- if (keylen_bytes == 16)
- return std::string("A128") + suffix;
- if (keylen_bytes == 24)
- return std::string("A192") + suffix;
- if (keylen_bytes == 32)
- return std::string("A256") + suffix;
- return std::string();
- }
- // Synthesizes an import algorithm given a key algorithm, so that
- // deserialization can re-use the ImportKey*() methods.
- blink::WebCryptoAlgorithm SynthesizeImportAlgorithmForClone(
- const blink::WebCryptoKeyAlgorithm& algorithm) {
- return blink::WebCryptoAlgorithm::AdoptParamsAndCreate(algorithm.Id(),
- nullptr);
- }
- } // namespace
- AesAlgorithm::AesAlgorithm(blink::WebCryptoKeyUsageMask all_key_usages,
- const std::string& jwk_suffix)
- : all_key_usages_(all_key_usages), jwk_suffix_(jwk_suffix) {
- }
- AesAlgorithm::AesAlgorithm(const std::string& jwk_suffix)
- : all_key_usages_(blink::kWebCryptoKeyUsageEncrypt |
- blink::kWebCryptoKeyUsageDecrypt |
- blink::kWebCryptoKeyUsageWrapKey |
- blink::kWebCryptoKeyUsageUnwrapKey),
- jwk_suffix_(jwk_suffix) {}
- Status AesAlgorithm::GenerateKey(const blink::WebCryptoAlgorithm& algorithm,
- bool extractable,
- blink::WebCryptoKeyUsageMask usages,
- GenerateKeyResult* result) const {
- Status status = CheckKeyCreationUsages(all_key_usages_, usages);
- if (status.IsError())
- return status;
- uint16_t keylen_bits = algorithm.AesKeyGenParams()->LengthBits();
- // 192-bit AES is intentionally unsupported (http://crbug.com/533699).
- if (keylen_bits == 192)
- return Status::ErrorAes192BitUnsupported();
- if (keylen_bits != 128 && keylen_bits != 256)
- return Status::ErrorGenerateAesKeyLength();
- return GenerateWebCryptoSecretKey(
- blink::WebCryptoKeyAlgorithm::CreateAes(algorithm.Id(), keylen_bits),
- extractable, usages, keylen_bits, result);
- }
- Status AesAlgorithm::ImportKey(blink::WebCryptoKeyFormat format,
- base::span<const uint8_t> key_data,
- const blink::WebCryptoAlgorithm& algorithm,
- bool extractable,
- blink::WebCryptoKeyUsageMask usages,
- blink::WebCryptoKey* key) const {
- switch (format) {
- case blink::kWebCryptoKeyFormatRaw:
- return ImportKeyRaw(key_data, algorithm, extractable, usages, key);
- case blink::kWebCryptoKeyFormatJwk:
- return ImportKeyJwk(key_data, algorithm, extractable, usages, key);
- default:
- return Status::ErrorUnsupportedImportKeyFormat();
- }
- }
- Status AesAlgorithm::ExportKey(blink::WebCryptoKeyFormat format,
- const blink::WebCryptoKey& key,
- std::vector<uint8_t>* buffer) const {
- switch (format) {
- case blink::kWebCryptoKeyFormatRaw:
- return ExportKeyRaw(key, buffer);
- case blink::kWebCryptoKeyFormatJwk:
- return ExportKeyJwk(key, buffer);
- default:
- return Status::ErrorUnsupportedExportKeyFormat();
- }
- }
- Status AesAlgorithm::ImportKeyRaw(base::span<const uint8_t> key_data,
- const blink::WebCryptoAlgorithm& algorithm,
- bool extractable,
- blink::WebCryptoKeyUsageMask usages,
- blink::WebCryptoKey* key) const {
- Status status = CheckKeyCreationUsages(all_key_usages_, usages);
- if (status.IsError())
- return status;
- const size_t keylen_bytes = key_data.size();
- // 192-bit AES is intentionally unsupported (http://crbug.com/533699).
- if (keylen_bytes == 24)
- return Status::ErrorAes192BitUnsupported();
- if (keylen_bytes != 16 && keylen_bytes != 32)
- return Status::ErrorImportAesKeyLength();
- // No possibility of overflow.
- unsigned int keylen_bits = keylen_bytes * 8;
- return CreateWebCryptoSecretKey(
- key_data,
- blink::WebCryptoKeyAlgorithm::CreateAes(algorithm.Id(), keylen_bits),
- extractable, usages, key);
- }
- Status AesAlgorithm::ImportKeyJwk(base::span<const uint8_t> key_data,
- const blink::WebCryptoAlgorithm& algorithm,
- bool extractable,
- blink::WebCryptoKeyUsageMask usages,
- blink::WebCryptoKey* key) const {
- Status status = CheckKeyCreationUsages(all_key_usages_, usages);
- if (status.IsError())
- return status;
- std::vector<uint8_t> raw_data;
- JwkReader jwk;
- status = ReadSecretKeyNoExpectedAlgJwk(key_data, extractable, usages,
- &raw_data, &jwk);
- if (status.IsError())
- return status;
- bool has_jwk_alg;
- std::string jwk_alg;
- status = jwk.GetAlg(&jwk_alg, &has_jwk_alg);
- if (status.IsError())
- return status;
- if (has_jwk_alg) {
- std::string expected_algorithm_name =
- MakeJwkAesAlgorithmName(jwk_suffix_, raw_data.size());
- if (jwk_alg != expected_algorithm_name) {
- // Give a different error message if the key length was wrong.
- if (jwk_alg == MakeJwkAesAlgorithmName(jwk_suffix_, 16) ||
- jwk_alg == MakeJwkAesAlgorithmName(jwk_suffix_, 24) ||
- jwk_alg == MakeJwkAesAlgorithmName(jwk_suffix_, 32)) {
- return Status::ErrorJwkIncorrectKeyLength();
- }
- return Status::ErrorJwkAlgorithmInconsistent();
- }
- }
- return ImportKeyRaw(raw_data, algorithm, extractable, usages, key);
- }
- Status AesAlgorithm::ExportKeyRaw(const blink::WebCryptoKey& key,
- std::vector<uint8_t>* buffer) const {
- *buffer = GetSymmetricKeyData(key);
- return Status::Success();
- }
- Status AesAlgorithm::ExportKeyJwk(const blink::WebCryptoKey& key,
- std::vector<uint8_t>* buffer) const {
- const std::vector<uint8_t>& raw_data = GetSymmetricKeyData(key);
- WriteSecretKeyJwk(raw_data,
- MakeJwkAesAlgorithmName(jwk_suffix_, raw_data.size()),
- key.Extractable(), key.Usages(), buffer);
- return Status::Success();
- }
- Status AesAlgorithm::DeserializeKeyForClone(
- const blink::WebCryptoKeyAlgorithm& algorithm,
- blink::WebCryptoKeyType type,
- bool extractable,
- blink::WebCryptoKeyUsageMask usages,
- base::span<const uint8_t> key_data,
- blink::WebCryptoKey* key) const {
- if (algorithm.ParamsType() != blink::kWebCryptoKeyAlgorithmParamsTypeAes ||
- type != blink::kWebCryptoKeyTypeSecret)
- return Status::ErrorUnexpected();
- return ImportKeyRaw(key_data, SynthesizeImportAlgorithmForClone(algorithm),
- extractable, usages, key);
- }
- Status AesAlgorithm::GetKeyLength(
- const blink::WebCryptoAlgorithm& key_length_algorithm,
- bool* has_length_bits,
- unsigned int* length_bits) const {
- *has_length_bits = true;
- *length_bits = key_length_algorithm.AesDerivedKeyParams()->LengthBits();
- if (*length_bits == 128 || *length_bits == 256)
- return Status::Success();
- // 192-bit AES is intentionally unsupported (http://crbug.com/533699).
- if (*length_bits == 192)
- return Status::ErrorAes192BitUnsupported();
- return Status::ErrorGetAesKeyLength();
- }
- } // namespace webcrypto
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