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/**
* Copyright (C) 2017 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects
* for all of the code used other than as permitted herein. If you modify
* file(s) with this exception, you may extend this exception to your
* version of the file(s), but you are not obligated to do so. If you do not
* wish to do so, delete this exception statement from your version. If you
* delete this exception statement from all source files in the program,
* then also delete it in the license file.
*/
#pragma once
#include <array>
#include <cstddef>
#include <string>
#include <third_party/murmurhash3/MurmurHash3.h>
#include <vector>
#include "mongo/base/data_range.h"
#include "mongo/base/status_with.h"
#include "mongo/bson/bsonmisc.h"
#include "mongo/bson/bsonobjbuilder.h"
#include "mongo/util/base64.h"
#include "mongo/util/secure_compare_memory.h"
namespace mongo {
struct BSONBinData;
class BSONObjBuilder;
/**
* Data structure with fixed sized byte array that can be used as HMAC key or result of a SHA
* computation.
*/
template <typename Traits>
class SHABlock {
public:
using HashType = typename Traits::HashType;
static constexpr size_t kHashLength = sizeof(HashType);
static constexpr auto kName = Traits::name;
SHABlock() = default;
SHABlock(HashType rawHash) : _hash(rawHash) {}
/**
* Constructs a SHABlock from a buffer of specified size.
*/
static StatusWith<SHABlock> fromBuffer(const uint8_t* input, size_t inputLen) {
if (inputLen != kHashLength) {
return {
ErrorCodes::InvalidLength,
str::stream() << "Unsupported " << Traits::name << " hash length: " << inputLen};
}
HashType newHash;
memcpy(newHash.data(), input, inputLen);
return SHABlock(newHash);
}
/**
* Computes a hash of 'input' from multiple contigous buffers.
*/
static SHABlock computeHash(std::initializer_list<ConstDataRange> input) {
return SHABlock{Traits::computeHash(input)};
}
/**
* Computes a hash of 'input' from one buffer.
*/
static SHABlock computeHash(const uint8_t* input, size_t inputLen) {
return computeHash({ConstDataRange(reinterpret_cast<const char*>(input), inputLen)});
}
/**
* Computes a HMAC keyed hash of 'input' using the key 'key'.
*/
static SHABlock computeHmac(const uint8_t* key,
size_t keyLen,
const uint8_t* input,
size_t inputLen) {
SHABlock output;
SHABlock::computeHmac(key, keyLen, input, inputLen, &output);
return output;
}
/**
* Computes a HMAC keyed hash of 'input' using the key 'key'. Writes the results into
* a pre-allocated SHABlock. This lets us allocate SHABlocks with the SecureAllocator.
*/
static void computeHmac(const uint8_t* key,
size_t keyLen,
const uint8_t* input,
size_t inputLen,
SHABlock* const output) {
return Traits::computeHmac(key, keyLen, input, inputLen, &(output->_hash));
}
const uint8_t* data() const& {
return _hash.data();
}
uint8_t* data() && = delete;
ConstDataRange toCDR() && = delete;
ConstDataRange toCDR() const& {
return ConstDataRange(reinterpret_cast<const char*>(_hash.data()), kHashLength);
}
size_t size() const {
return _hash.size();
}
/**
* Make a new SHABlock from a BSON BinData value.
*/
static StatusWith<SHABlock> fromBinData(const BSONBinData& binData) {
if (binData.type != BinDataGeneral) {
return {ErrorCodes::UnsupportedFormat,
str::stream() << Traits::name << " only accepts BinDataGeneral type"};
}
if (binData.length != kHashLength) {
return {ErrorCodes::UnsupportedFormat,
str::stream() << "Unsupported " << Traits::name << " hash length: "
<< binData.length};
}
HashType newHash;
memcpy(newHash.data(), binData.data, binData.length);
return SHABlock(newHash);
}
/**
* Make a new SHABlock from a vector of bytes representing bindata. For IDL.
*/
static SHABlock fromBinData(const std::vector<unsigned char>& bytes) {
HashType newHash;
uassert(ErrorCodes::UnsupportedFormat,
str::stream() << "Unsupported " << Traits::name << " hash length: " << bytes.size(),
bytes.size() == kHashLength);
memcpy(newHash.data(), bytes.data(), bytes.size());
return SHABlock(newHash);
}
/**
* Append this to a builder using the given name as a BSON BinData type value.
*/
void appendAsBinData(BSONObjBuilder& builder, StringData fieldName) const {
builder.appendBinData(fieldName, _hash.size(), BinDataGeneral, _hash.data());
}
/**
* Do a bitwise xor against another SHABlock and replace the current contents of this block
* with the result.
*/
void xorInline(const SHABlock& other) {
for (size_t x = 0; x < _hash.size(); x++) {
_hash[x] ^= other._hash[x];
}
}
/**
* Base64 encoding of the sha block as a string.
*/
std::string toString() const {
return base64::encode(reinterpret_cast<const char*>(_hash.data()), _hash.size());
}
bool operator==(const SHABlock& other) const {
return consttimeMemEqual(this->_hash.data(), other._hash.data(), kHashLength);
}
bool operator!=(const SHABlock& other) const {
return !(*this == other);
}
/**
* Custom hasher so SHABlocks can be used in unordered data structures.
*
* ex: std::unordered_set<SHABlock, SHABlock::Hash> shaSet;
*/
struct Hash {
std::size_t operator()(const SHABlock& shaBlock) const {
uint32_t hash;
MurmurHash3_x86_32(shaBlock.data(), SHABlock::kHashLength, 0, &hash);
return hash;
}
};
private:
// The backing array of bytes for the sha block
HashType _hash;
};
template <typename T>
constexpr size_t SHABlock<T>::kHashLength;
template <typename Traits>
std::ostream& operator<<(std::ostream& os, const SHABlock<Traits>& sha) {
return os << sha.toString();
}
} // namespace mongo
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