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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "NSSCipherStrategy.h"
#include <algorithm>
#include <cstdlib>
#include <cstring>
#include <memory>
#include <type_traits>
#include <utility>
#include "mozilla/Assertions.h"
#include "mozilla/ResultExtensions.h"
// NSS includes
#include "blapit.h"
#include "pk11pub.h"
#include "pkcs11t.h"
#include "seccomon.h"
#include "secmodt.h"
namespace mozilla::dom::quota {
static_assert(sizeof(NSSCipherStrategy::KeyType) == 32);
static_assert(NSSCipherStrategy::BlockPrefixLength == 32);
static_assert(NSSCipherStrategy::BasicBlockSize == 16);
Result<NSSCipherStrategy::KeyType, nsresult> NSSCipherStrategy::GenerateKey() {
const auto slot = UniquePK11SlotInfo{PK11_GetInternalSlot()};
if (slot == nullptr) {
return Err(NS_ERROR_FAILURE);
}
const auto symKey = UniquePK11SymKey{PK11_KeyGen(
slot.get(), CKM_CHACHA20_KEY_GEN, nullptr, sizeof(KeyType), nullptr)};
if (symKey == nullptr) {
return Err(NS_ERROR_FAILURE);
}
if (PK11_ExtractKeyValue(symKey.get()) != SECSuccess) {
return Err(NS_ERROR_FAILURE);
}
// No need to free keyData as it is a buffer managed by symKey.
SECItem* keyData = PK11_GetKeyData(symKey.get());
if (keyData == nullptr) {
return Err(NS_ERROR_FAILURE);
}
KeyType key;
MOZ_RELEASE_ASSERT(keyData->len == key.size());
std::copy(keyData->data, keyData->data + key.size(), key.data());
return key;
}
nsresult NSSCipherStrategy::Init(const CipherMode aMode,
const Span<const uint8_t> aKey,
const Span<const uint8_t> aInitialIv) {
MOZ_ASSERT_IF(CipherMode::Encrypt == aMode, aInitialIv.Length() == 32);
mMode.init(aMode);
mIv.AppendElements(aInitialIv);
const auto slot = UniquePK11SlotInfo{PK11_GetInternalSlot()};
if (slot == nullptr) {
return NS_ERROR_FAILURE;
}
SECItem keyItem;
keyItem.data = const_cast<uint8_t*>(aKey.Elements());
keyItem.len = aKey.Length();
const auto symKey = UniquePK11SymKey{
PK11_ImportSymKey(slot.get(), CKM_CHACHA20_POLY1305, PK11_OriginUnwrap,
CKA_ENCRYPT, &keyItem, nullptr)};
if (symKey == nullptr) {
return NS_ERROR_FAILURE;
}
SECItem empty = {siBuffer, nullptr, 0};
auto pk11Context = UniquePK11Context{PK11_CreateContextBySymKey(
CKM_CHACHA20_POLY1305,
CKA_NSS_MESSAGE |
(CipherMode::Encrypt == aMode ? CKA_ENCRYPT : CKA_DECRYPT),
symKey.get(), &empty)};
if (pk11Context == nullptr) {
return NS_ERROR_FAILURE;
}
mPK11Context.init(std::move(pk11Context));
return NS_OK;
}
nsresult NSSCipherStrategy::Cipher(const Span<uint8_t> aIv,
const Span<const uint8_t> aIn,
const Span<uint8_t> aOut) {
if (CipherMode::Encrypt == *mMode) {
MOZ_RELEASE_ASSERT(aIv.Length() == mIv.Length());
memcpy(aIv.Elements(), mIv.Elements(), aIv.Length());
}
// XXX make tag a separate parameter
constexpr size_t tagLen = 16;
const auto tag = aIv.Last(tagLen);
// tag is const on decrypt, but returned on encrypt
const auto iv = aIv.First(12);
MOZ_ASSERT(tag.Length() + iv.Length() <= aIv.Length());
int outLen;
// aIn and aOut may not overlap resp. be the same, so we can't do this
// in-place.
const SECStatus rv = PK11_AEADOp(
mPK11Context->get(), CKG_GENERATE_COUNTER, 0, iv.Elements(), iv.Length(),
nullptr, 0, aOut.Elements(), &outLen, aOut.Length(), tag.Elements(),
tag.Length(), aIn.Elements(), aIn.Length());
if (CipherMode::Encrypt == *mMode) {
memcpy(mIv.Elements(), aIv.Elements(), aIv.Length());
}
return MapSECStatus(rv);
}
template <size_t N>
static std::array<uint8_t, N> MakeRandomData() {
std::array<uint8_t, N> res;
const auto rv = PK11_GenerateRandom(res.data(), res.size());
/// XXX Allow return of error code to handle this gracefully.
MOZ_RELEASE_ASSERT(rv == SECSuccess);
return res;
}
std::array<uint8_t, NSSCipherStrategy::BlockPrefixLength>
NSSCipherStrategy::MakeBlockPrefix() {
return MakeRandomData<BlockPrefixLength>();
}
Span<const uint8_t> NSSCipherStrategy::SerializeKey(const KeyType& aKey) {
return Span(aKey);
}
Maybe<NSSCipherStrategy::KeyType> NSSCipherStrategy::DeserializeKey(
const Span<const uint8_t>& aSerializedKey) {
KeyType res;
if (res.size() != aSerializedKey.size()) {
return Nothing();
}
std::copy(aSerializedKey.cbegin(), aSerializedKey.cend(), res.begin());
return Some(res);
}
} // namespace mozilla::dom::quota
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