// Copyright (c) 2008 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 "base/hmac.h"
#include <nss.h>
#include <pk11pub.h>
#include "base/logging.h"
#include "base/nss_util.h"
#include "base/scoped_ptr.h"
namespace {
template <typename Type, void (*Destroyer)(Type*)>
struct NSSDestroyer {
void operator()(Type* ptr) const {
if (ptr)
Destroyer(ptr);
}
};
void DestroyContext(PK11Context* context) {
PK11_DestroyContext(context, PR_TRUE);
}
// Define some convenient scopers around NSS pointers.
typedef scoped_ptr_malloc<
PK11SlotInfo, NSSDestroyer<PK11SlotInfo, PK11_FreeSlot> > ScopedNSSSlot;
typedef scoped_ptr_malloc<
PK11SymKey, NSSDestroyer<PK11SymKey, PK11_FreeSymKey> > ScopedNSSSymKey;
typedef scoped_ptr_malloc<
PK11Context, NSSDestroyer<PK11Context, DestroyContext> > ScopedNSSContext;
} // namespace
namespace base {
struct HMACPlatformData {
ScopedNSSSlot slot_;
ScopedNSSSymKey sym_key_;
};
HMAC::HMAC(HashAlgorithm hash_alg)
: hash_alg_(hash_alg), plat_(new HMACPlatformData()) {
// Only SHA-1 digest is supported now.
DCHECK(hash_alg_ == SHA1);
}
bool HMAC::Init(const unsigned char *key, int key_length) {
base::EnsureNSSInit();
if (hash_alg_ != SHA1) {
NOTREACHED();
return false;
}
if (plat_->slot_.get()) {
// Init must not be called more than twice on the same HMAC object.
NOTREACHED();
return false;
}
plat_->slot_.reset(PK11_GetBestSlot(CKM_SHA_1_HMAC, NULL));
if (!plat_->slot_.get()) {
NOTREACHED();
return false;
}
SECItem key_item;
key_item.type = siBuffer;
key_item.data = const_cast<unsigned char*>(key); // NSS API isn't const.
key_item.len = key_length;
plat_->sym_key_.reset(PK11_ImportSymKey(plat_->slot_.get(),
CKM_SHA_1_HMAC,
PK11_OriginUnwrap,
CKA_SIGN,
&key_item,
NULL));
if (!plat_->sym_key_.get()) {
NOTREACHED();
return false;
}
return true;
}
HMAC::~HMAC() {
}
bool HMAC::Sign(const std::string& data,
unsigned char* digest,
int digest_length) {
if (!plat_->sym_key_.get()) {
// Init has not been called before Sign.
NOTREACHED();
return false;
}
SECItem param = { siBuffer, NULL, 0 };
ScopedNSSContext context(PK11_CreateContextBySymKey(CKM_SHA_1_HMAC,
CKA_SIGN,
plat_->sym_key_.get(),
¶m));
if (!context.get()) {
NOTREACHED();
return false;
}
if (PK11_DigestBegin(context.get()) != SECSuccess) {
NOTREACHED();
return false;
}
if (PK11_DigestOp(context.get(),
reinterpret_cast<const unsigned char*>(data.data()),
data.length()) != SECSuccess) {
NOTREACHED();
return false;
}
unsigned int len = 0;
if (PK11_DigestFinal(context.get(),
digest, &len, digest_length) != SECSuccess) {
NOTREACHED();
return false;
}
return true;
}
} // namespace base