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// Copyright (c) 2011 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 "crypto/signature_verifier.h"
#include <cryptohi.h>
#include <keyhi.h>
#include <pk11pub.h>
#include <secerr.h>
#include <sechash.h>
#include <stdlib.h>
#include "base/logging.h"
#include "crypto/nss_util.h"
#include "crypto/third_party/nss/chromium-nss.h"
namespace crypto {
namespace {
HASH_HashType ToNSSHashType(SignatureVerifier::HashAlgorithm hash_alg) {
switch (hash_alg) {
case SignatureVerifier::SHA1:
return HASH_AlgSHA1;
case SignatureVerifier::SHA256:
return HASH_AlgSHA256;
}
return HASH_AlgNULL;
}
SECStatus VerifyRSAPSS_End(SECKEYPublicKey* public_key,
HASHContext* hash_context,
HASH_HashType mask_hash_alg,
unsigned int salt_len,
const unsigned char* signature,
unsigned int signature_len) {
unsigned int hash_len = HASH_ResultLenContext(hash_context);
std::vector<unsigned char> hash(hash_len);
HASH_End(hash_context, &hash[0], &hash_len, hash.size());
unsigned int modulus_len = SECKEY_PublicKeyStrength(public_key);
if (signature_len != modulus_len) {
PORT_SetError(SEC_ERROR_BAD_SIGNATURE);
return SECFailure;
}
std::vector<unsigned char> enc(signature_len);
SECStatus rv = PK11_PubEncryptRaw(public_key, &enc[0],
const_cast<unsigned char*>(signature),
signature_len, NULL);
if (rv != SECSuccess) {
LOG(WARNING) << "PK11_PubEncryptRaw failed";
return rv;
}
return emsa_pss_verify(&hash[0], &enc[0], enc.size(),
HASH_GetType(hash_context), mask_hash_alg,
salt_len);
}
} // namespace
SignatureVerifier::SignatureVerifier()
: vfy_context_(NULL),
hash_alg_(SHA1),
mask_hash_alg_(SHA1),
salt_len_(0),
public_key_(NULL),
hash_context_(NULL) {
EnsureNSSInit();
}
SignatureVerifier::~SignatureVerifier() {
Reset();
}
bool SignatureVerifier::VerifyInit(const uint8* signature_algorithm,
int signature_algorithm_len,
const uint8* signature,
int signature_len,
const uint8* public_key_info,
int public_key_info_len) {
if (vfy_context_ || hash_context_)
return false;
signature_.assign(signature, signature + signature_len);
SECKEYPublicKey* public_key = DecodePublicKeyInfo(public_key_info,
public_key_info_len);
if (!public_key)
return false;
PLArenaPool* arena = PORT_NewArena(DER_DEFAULT_CHUNKSIZE);
if (!arena) {
SECKEY_DestroyPublicKey(public_key);
return false;
}
SECItem sig_alg_der;
sig_alg_der.type = siBuffer;
sig_alg_der.data = const_cast<uint8*>(signature_algorithm);
sig_alg_der.len = signature_algorithm_len;
SECAlgorithmID sig_alg_id;
SECStatus rv;
rv = SEC_QuickDERDecodeItem(arena, &sig_alg_id,
SEC_ASN1_GET(SECOID_AlgorithmIDTemplate),
&sig_alg_der);
if (rv != SECSuccess) {
SECKEY_DestroyPublicKey(public_key);
PORT_FreeArena(arena, PR_TRUE);
return false;
}
SECItem sig;
sig.type = siBuffer;
sig.data = const_cast<uint8*>(signature);
sig.len = signature_len;
SECOidTag hash_alg_tag;
vfy_context_ = VFY_CreateContextWithAlgorithmID(public_key, &sig,
&sig_alg_id, &hash_alg_tag,
NULL);
SECKEY_DestroyPublicKey(public_key); // Done with public_key.
PORT_FreeArena(arena, PR_TRUE); // Done with sig_alg_id.
if (!vfy_context_) {
// A corrupted RSA signature could be detected without the data, so
// VFY_CreateContextWithAlgorithmID may fail with SEC_ERROR_BAD_SIGNATURE
// (-8182).
return false;
}
rv = VFY_Begin(vfy_context_);
if (rv != SECSuccess) {
NOTREACHED();
return false;
}
return true;
}
bool SignatureVerifier::VerifyInitRSAPSS(HashAlgorithm hash_alg,
HashAlgorithm mask_hash_alg,
int salt_len,
const uint8* signature,
int signature_len,
const uint8* public_key_info,
int public_key_info_len) {
if (vfy_context_ || hash_context_)
return false;
signature_.assign(signature, signature + signature_len);
SECKEYPublicKey* public_key = DecodePublicKeyInfo(public_key_info,
public_key_info_len);
if (!public_key)
return false;
public_key_ = public_key;
hash_alg_ = hash_alg;
mask_hash_alg_ = mask_hash_alg;
salt_len_ = salt_len;
hash_context_ = HASH_Create(ToNSSHashType(hash_alg_));
if (!hash_context_)
return false;
HASH_Begin(hash_context_);
return true;
}
void SignatureVerifier::VerifyUpdate(const uint8* data_part,
int data_part_len) {
if (vfy_context_) {
SECStatus rv = VFY_Update(vfy_context_, data_part, data_part_len);
DCHECK_EQ(SECSuccess, rv);
} else {
HASH_Update(hash_context_, data_part, data_part_len);
}
}
bool SignatureVerifier::VerifyFinal() {
SECStatus rv;
if (vfy_context_) {
rv = VFY_End(vfy_context_);
} else {
rv = VerifyRSAPSS_End(public_key_, hash_context_,
ToNSSHashType(mask_hash_alg_), salt_len_,
signature_.data(),
signature_.size());
}
Reset();
// If signature verification fails, the error code is
// SEC_ERROR_BAD_SIGNATURE (-8182).
return (rv == SECSuccess);
}
// static
SECKEYPublicKey* SignatureVerifier::DecodePublicKeyInfo(
const uint8* public_key_info,
int public_key_info_len) {
CERTSubjectPublicKeyInfo* spki = NULL;
SECItem spki_der;
spki_der.type = siBuffer;
spki_der.data = const_cast<uint8*>(public_key_info);
spki_der.len = public_key_info_len;
spki = SECKEY_DecodeDERSubjectPublicKeyInfo(&spki_der);
if (!spki)
return NULL;
SECKEYPublicKey* public_key = SECKEY_ExtractPublicKey(spki);
SECKEY_DestroySubjectPublicKeyInfo(spki); // Done with spki.
return public_key;
}
void SignatureVerifier::Reset() {
if (vfy_context_) {
VFY_DestroyContext(vfy_context_, PR_TRUE);
vfy_context_ = NULL;
}
if (hash_context_) {
HASH_Destroy(hash_context_);
hash_context_ = NULL;
}
if (public_key_) {
SECKEY_DestroyPublicKey(public_key_);
public_key_ = NULL;
}
signature_.clear();
}
} // namespace crypto
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