/*
* Copyright 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <keymaster/km_openssl/ecdsa_operation.h>
#include <openssl/ecdsa.h>
#include <keymaster/km_openssl/ec_key.h>
#include <keymaster/km_openssl/openssl_err.h>
#include <keymaster/km_openssl/openssl_utils.h>
namespace keymaster {
static const keymaster_digest_t supported_digests[] = {KM_DIGEST_NONE, KM_DIGEST_SHA1,
KM_DIGEST_SHA_2_224, KM_DIGEST_SHA_2_256,
KM_DIGEST_SHA_2_384, KM_DIGEST_SHA_2_512};
OperationPtr EcdsaOperationFactory::CreateOperation(Key&& key, const AuthorizationSet& begin_params,
keymaster_error_t* error) const {
const EcKey& ecdsa_key = static_cast<EcKey&>(key);
UniquePtr<EVP_PKEY, EVP_PKEY_Delete> pkey(EVP_PKEY_new());
if (!ecdsa_key.InternalToEvp(pkey.get())) {
*error = KM_ERROR_UNKNOWN_ERROR;
return nullptr;
}
keymaster_digest_t digest;
if (!GetAndValidateDigest(begin_params, ecdsa_key, &digest, error)) return nullptr;
*error = KM_ERROR_OK;
auto op = OperationPtr(InstantiateOperation(key.hw_enforced_move(), key.sw_enforced_move(),
digest, pkey.release()));
if (!op) *error = KM_ERROR_MEMORY_ALLOCATION_FAILED;
return op;
}
const keymaster_digest_t* EcdsaOperationFactory::SupportedDigests(size_t* digest_count) const {
*digest_count = array_length(supported_digests);
return supported_digests;
}
EcdsaOperation::~EcdsaOperation() {
if (ecdsa_key_ != nullptr)
EVP_PKEY_free(ecdsa_key_);
EVP_MD_CTX_cleanup(&digest_ctx_);
}
keymaster_error_t EcdsaOperation::InitDigest() {
switch (digest_) {
case KM_DIGEST_NONE:
return KM_ERROR_OK;
case KM_DIGEST_MD5:
return KM_ERROR_UNSUPPORTED_DIGEST;
case KM_DIGEST_SHA1:
digest_algorithm_ = EVP_sha1();
return KM_ERROR_OK;
case KM_DIGEST_SHA_2_224:
digest_algorithm_ = EVP_sha224();
return KM_ERROR_OK;
case KM_DIGEST_SHA_2_256:
digest_algorithm_ = EVP_sha256();
return KM_ERROR_OK;
case KM_DIGEST_SHA_2_384:
digest_algorithm_ = EVP_sha384();
return KM_ERROR_OK;
case KM_DIGEST_SHA_2_512:
digest_algorithm_ = EVP_sha512();
return KM_ERROR_OK;
default:
return KM_ERROR_UNSUPPORTED_DIGEST;
}
}
inline size_t min(size_t a, size_t b) {
return (a < b) ? a : b;
}
keymaster_error_t EcdsaOperation::StoreData(const Buffer& input, size_t* input_consumed) {
if (!data_.reserve((EVP_PKEY_bits(ecdsa_key_) + 7) / 8))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
if (!data_.write(input.peek_read(), min(data_.available_write(), input.available_read())))
return KM_ERROR_UNKNOWN_ERROR;
*input_consumed = input.available_read();
return KM_ERROR_OK;
}
keymaster_error_t EcdsaSignOperation::Begin(const AuthorizationSet& /* input_params */,
AuthorizationSet* /* output_params */) {
auto rc = GenerateRandom(reinterpret_cast<uint8_t*>(&operation_handle_),
(size_t)sizeof(operation_handle_));
if (rc != KM_ERROR_OK) return rc;
keymaster_error_t error = InitDigest();
if (error != KM_ERROR_OK)
return error;
if (digest_ == KM_DIGEST_NONE)
return KM_ERROR_OK;
EVP_PKEY_CTX* pkey_ctx;
if (EVP_DigestSignInit(&digest_ctx_, &pkey_ctx, digest_algorithm_, nullptr /* engine */,
ecdsa_key_) != 1)
return TranslateLastOpenSslError();
return KM_ERROR_OK;
}
keymaster_error_t EcdsaSignOperation::Update(const AuthorizationSet& /* additional_params */,
const Buffer& input,
AuthorizationSet* /* output_params */,
Buffer* /* output */, size_t* input_consumed) {
if (digest_ == KM_DIGEST_NONE)
return StoreData(input, input_consumed);
if (EVP_DigestSignUpdate(&digest_ctx_, input.peek_read(), input.available_read()) != 1)
return TranslateLastOpenSslError();
*input_consumed = input.available_read();
return KM_ERROR_OK;
}
keymaster_error_t EcdsaSignOperation::Finish(const AuthorizationSet& additional_params,
const Buffer& input, const Buffer& /* signature */,
AuthorizationSet* /* output_params */,
Buffer* output) {
if (!output)
return KM_ERROR_OUTPUT_PARAMETER_NULL;
keymaster_error_t error = UpdateForFinish(additional_params, input);
if (error != KM_ERROR_OK)
return error;
size_t siglen;
if (digest_ == KM_DIGEST_NONE) {
UniquePtr<EC_KEY, EC_KEY_Delete> ecdsa(EVP_PKEY_get1_EC_KEY(ecdsa_key_));
if (!ecdsa.get())
return TranslateLastOpenSslError();
output->Reinitialize(ECDSA_size(ecdsa.get()));
unsigned int siglen_tmp;
if (!ECDSA_sign(0 /* type -- ignored */, data_.peek_read(), data_.available_read(),
output->peek_write(), &siglen_tmp, ecdsa.get()))
return TranslateLastOpenSslError();
siglen = siglen_tmp;
} else {
if (EVP_DigestSignFinal(&digest_ctx_, nullptr /* signature */, &siglen) != 1)
return TranslateLastOpenSslError();
if (!output->Reinitialize(siglen))
return KM_ERROR_MEMORY_ALLOCATION_FAILED;
if (EVP_DigestSignFinal(&digest_ctx_, output->peek_write(), &siglen) <= 0)
return TranslateLastOpenSslError();
}
if (!output->advance_write(siglen))
return KM_ERROR_UNKNOWN_ERROR;
return KM_ERROR_OK;
}
keymaster_error_t EcdsaVerifyOperation::Begin(const AuthorizationSet& /* input_params */,
AuthorizationSet* /* output_params */) {
auto rc = GenerateRandom(reinterpret_cast<uint8_t*>(&operation_handle_),
(size_t)sizeof(operation_handle_));
if (rc != KM_ERROR_OK) return rc;
keymaster_error_t error = InitDigest();
if (error != KM_ERROR_OK)
return error;
if (digest_ == KM_DIGEST_NONE)
return KM_ERROR_OK;
EVP_PKEY_CTX* pkey_ctx;
if (EVP_DigestVerifyInit(&digest_ctx_, &pkey_ctx, digest_algorithm_, nullptr /* engine */,
ecdsa_key_) != 1)
return TranslateLastOpenSslError();
return KM_ERROR_OK;
}
keymaster_error_t EcdsaVerifyOperation::Update(const AuthorizationSet& /* additional_params */,
const Buffer& input,
AuthorizationSet* /* output_params */,
Buffer* /* output */, size_t* input_consumed) {
if (digest_ == KM_DIGEST_NONE)
return StoreData(input, input_consumed);
if (EVP_DigestVerifyUpdate(&digest_ctx_, input.peek_read(), input.available_read()) != 1)
return TranslateLastOpenSslError();
*input_consumed = input.available_read();
return KM_ERROR_OK;
}
keymaster_error_t EcdsaVerifyOperation::Finish(const AuthorizationSet& additional_params,
const Buffer& input, const Buffer& signature,
AuthorizationSet* /* output_params */,
Buffer* /* output */) {
keymaster_error_t error = UpdateForFinish(additional_params, input);
if (error != KM_ERROR_OK)
return error;
if (digest_ == KM_DIGEST_NONE) {
UniquePtr<EC_KEY, EC_KEY_Delete> ecdsa(EVP_PKEY_get1_EC_KEY(ecdsa_key_));
if (!ecdsa.get())
return TranslateLastOpenSslError();
int result =
ECDSA_verify(0 /* type -- ignored */, data_.peek_read(), data_.available_read(),
signature.peek_read(), signature.available_read(), ecdsa.get());
if (result < 0)
return TranslateLastOpenSslError();
else if (result == 0)
return KM_ERROR_VERIFICATION_FAILED;
} else if (!EVP_DigestVerifyFinal(&digest_ctx_, signature.peek_read(),
signature.available_read()))
return KM_ERROR_VERIFICATION_FAILED;
return KM_ERROR_OK;
}
} // namespace keymaster