Atmosphere-libs/libvapours/include/vapours/crypto/impl/crypto_rsa_pkcs1_impl.hpp
2022-03-23 09:15:55 -07:00

95 lines
3.2 KiB
C++

/*
* Copyright (c) Atmosphère-NX
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
#include <vapours/common.hpp>
#include <vapours/assert.hpp>
#include <vapours/util.hpp>
#include <vapours/crypto/impl/crypto_hash_function.hpp>
namespace ams::crypto::impl {
template<HashFunction Hash>
class RsaPkcs1Impl {
NON_COPYABLE(RsaPkcs1Impl);
NON_MOVEABLE(RsaPkcs1Impl);
public:
static constexpr size_t HashSize = Hash::HashSize;
public:
RsaPkcs1Impl() { /* ... */ }
~RsaPkcs1Impl() { /* ... */ }
void BuildPad(void *out_block, size_t block_size, Hash *hash) {
AMS_ASSERT(block_size >= 2 + 1 + sizeof(Hash::Asn1Identifier) + HashSize);
u8 *dst = static_cast<u8 *>(out_block);
*(dst++) = 0x00;
*(dst++) = 0x01;
const size_t pad_len = block_size - (2 + 1 + sizeof(Hash::Asn1Identifier) + HashSize);
std::memset(dst, 0xFF, pad_len);
dst += pad_len;
*(dst++) = 0x00;
std::memcpy(dst, Hash::Asn1Identifier, sizeof(Hash::Asn1Identifier));
dst += sizeof(Hash::Asn1Identifier);
hash->GetHash(dst, HashSize);
}
bool CheckPad(const u8 *src, size_t block_size, Hash *hash) {
/* Check that block size is minimally big enough. */
if (block_size < 2 + 1 + sizeof(Hash::Asn1Identifier) + HashSize) {
return false;
}
/* Check that the padding if correctly of form 0001FF..FF00 */
if (*(src++) != 0x00) {
return false;
}
if (*(src++) != 0x01) {
return false;
}
const size_t pad_len = block_size - (2 + 1 + sizeof(Hash::Asn1Identifier) + HashSize);
for (size_t i = 0; i < pad_len; ++i) {
if (*(src++) != 0xFF) {
return false;
}
}
if (*(src++) != 0x00) {
return false;
}
/* Check that the asn1 identifier matches. */
if (std::memcmp(src, Hash::Asn1Identifier, sizeof(Hash::Asn1Identifier)) != 0) {
return false;
}
src += sizeof(Hash::Asn1Identifier);
/* Check the hash. */
u8 calc_hash[HashSize];
hash->GetHash(calc_hash, sizeof(calc_hash));
return std::memcmp(calc_hash, src, HashSize) == 0;
}
};
}