mirror of
https://github.com/Atmosphere-NX/Atmosphere.git
synced 2024-12-24 11:16:11 +00:00
278 lines
11 KiB
C++
278 lines
11 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 <stratosphere.hpp>
|
||
|
|
|
||
|
|
namespace ams::spl::impl {
|
||
|
|
|
||
|
|
constexpr inline int BitsPerByte = BITSIZEOF(u8);
|
||
|
|
|
||
|
|
/* Nintendo implements CTR_DRBG for their csrng. We will do the same. */
|
||
|
|
template<typename BlockCipher, size_t KeySize, bool UseDerivation>
|
||
|
|
class CtrDrbg {
|
||
|
|
public:
|
||
|
|
static constexpr int KeyLen = KeySize * BitsPerByte;
|
||
|
|
static constexpr int OutLen = BlockCipher::BlockSize * BitsPerByte;
|
||
|
|
static constexpr int SeedLen = KeyLen + OutLen;
|
||
|
|
static constexpr int MaxNumberOfBitsPerRequest = (1 << 19);
|
||
|
|
static constexpr int ReseedInterval = 0x7FFFFFF0;
|
||
|
|
|
||
|
|
static constexpr size_t OutSize = OutLen / BitsPerByte;
|
||
|
|
static constexpr size_t SeedSize = SeedLen / BitsPerByte;
|
||
|
|
static constexpr size_t RequestSizeMax = MaxNumberOfBitsPerRequest / BitsPerByte;
|
||
|
|
|
||
|
|
static_assert(SeedSize % OutSize == 0);
|
||
|
|
private:
|
||
|
|
class Bcc {
|
||
|
|
private:
|
||
|
|
u8 *m_buffer;
|
||
|
|
const BlockCipher *m_cipher;
|
||
|
|
size_t m_offset;
|
||
|
|
public:
|
||
|
|
Bcc(u8 *buffer, const BlockCipher *cipher) : m_buffer(buffer), m_cipher(cipher), m_offset(0) { /* ... */ }
|
||
|
|
|
||
|
|
void Process(const void *data, size_t size) {
|
||
|
|
const u8 *data_8 = static_cast<const u8 *>(data);
|
||
|
|
size_t remaining = size;
|
||
|
|
|
||
|
|
while (m_offset + remaining >= OutSize) {
|
||
|
|
const size_t xor_size = OutSize - m_offset;
|
||
|
|
|
||
|
|
Xor(m_buffer + m_offset, data_8, xor_size);
|
||
|
|
m_cipher->EncryptBlock(m_buffer, OutSize, m_buffer, OutSize);
|
||
|
|
|
||
|
|
data_8 += xor_size;
|
||
|
|
remaining -= xor_size;
|
||
|
|
|
||
|
|
m_offset = 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
Xor(m_buffer + m_offset, data_8, remaining);
|
||
|
|
m_offset += remaining;
|
||
|
|
}
|
||
|
|
|
||
|
|
void Flush() {
|
||
|
|
if (m_offset != 0) {
|
||
|
|
m_cipher->EncryptBlock(m_buffer, OutSize, m_buffer, OutSize);
|
||
|
|
m_offset = 0;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
};
|
||
|
|
private:
|
||
|
|
BlockCipher m_block_cipher;
|
||
|
|
u8 m_v[OutSize];
|
||
|
|
u8 m_key[KeySize];
|
||
|
|
u8 m_work1[SeedSize];
|
||
|
|
u8 m_work2[SeedSize];
|
||
|
|
int m_reseed_counter;
|
||
|
|
private:
|
||
|
|
static void Xor(void *dst, const void *src, size_t size) {
|
||
|
|
const u8 *src_u8 = static_cast<const u8 *>(src);
|
||
|
|
u8 *dst_u8 = static_cast<u8 *>(dst);
|
||
|
|
|
||
|
|
for (size_t i = 0; i < size; i++) {
|
||
|
|
dst_u8[i] ^= src_u8[i];
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
static void Increment(void *v) {
|
||
|
|
u8 *v_8 = static_cast<u8 *>(v);
|
||
|
|
|
||
|
|
for (int i = OutSize - 1; i >= 0; --i) {
|
||
|
|
if ((++v_8[i]) != 0) {
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
private:
|
||
|
|
void DeriveSeed(void *seed, const void *a, size_t a_size, const void *b, size_t b_size, const void *c, size_t c_size) {
|
||
|
|
/* Determine sizes. */
|
||
|
|
const u32 in_size = a_size + b_size + c_size;
|
||
|
|
const u32 out_size = SeedSize;
|
||
|
|
|
||
|
|
/* Create header/footer. */
|
||
|
|
u32 header[2];
|
||
|
|
util::StoreBigEndian(header + 0, in_size);
|
||
|
|
util::StoreBigEndian(header + 1, out_size);
|
||
|
|
const u8 footer = 0x80;
|
||
|
|
|
||
|
|
/* Create seed as 000102... */
|
||
|
|
u8 *seed_8 = static_cast<u8 *>(seed);
|
||
|
|
for (size_t i = 0; i < KeySize; ++i) {
|
||
|
|
seed_8[i] = i;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Initialize block cipher. */
|
||
|
|
m_block_cipher.Initialize(seed_8, KeySize);
|
||
|
|
|
||
|
|
/* Perform derivation. */
|
||
|
|
for (u32 block = 0; block < SeedSize / OutSize; ++block) {
|
||
|
|
/* Create the block index value. */
|
||
|
|
u32 block_value;
|
||
|
|
util::StoreBigEndian(std::addressof(block_value), block);
|
||
|
|
|
||
|
|
/* Get the target block. */
|
||
|
|
u8 *target = seed_8 + block * OutSize;
|
||
|
|
std::memset(target, 0, OutSize);
|
||
|
|
|
||
|
|
/* Create block processor. */
|
||
|
|
Bcc bcc(target, std::addressof(m_block_cipher));
|
||
|
|
|
||
|
|
/* Process block value. */
|
||
|
|
bcc.Process(std::addressof(block_value), sizeof(block_value));
|
||
|
|
bcc.Flush();
|
||
|
|
|
||
|
|
/* Process header/data. */
|
||
|
|
bcc.Process(header, sizeof(header));
|
||
|
|
bcc.Process(a, a_size);
|
||
|
|
bcc.Process(b, b_size);
|
||
|
|
bcc.Process(c, c_size);
|
||
|
|
bcc.Process(footer, std::addressof(footer));
|
||
|
|
bcc.Flush();
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Initialize block cipher. */
|
||
|
|
m_block_cipher.Initialize(seed_8, KeySize);
|
||
|
|
|
||
|
|
/* Encrypt seed. */
|
||
|
|
m_block_cipher.EncryptBlock(seed_8, OutSize, seed_8 + KeySize, OutSize);
|
||
|
|
for (size_t offset = 0; offset < SeedSize - OutSize; offset += OutSize) {
|
||
|
|
m_block_cipher.EncryptBlock(seed_8 + offset + OutSize, OutSize, seed_8 + offset, OutSize);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
void UpdateStates(void *key, void *v, const void *provided_data) {
|
||
|
|
/* Initialize block cipher. */
|
||
|
|
m_block_cipher.Initialize(key, KeySize);
|
||
|
|
|
||
|
|
/* Update work. */
|
||
|
|
for (size_t offset = 0; offset < SeedSize; offset += OutSize) {
|
||
|
|
Increment(v);
|
||
|
|
m_block_cipher.EncryptBlock(std::addressof(m_work2[offset]), OutSize, v, OutSize);
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Xor work with provided data. */
|
||
|
|
Xor(m_work2, provided_data, SeedSize);
|
||
|
|
|
||
|
|
/* Copy to key/v. */
|
||
|
|
std::memcpy(key, m_work2 + 0, KeySize);
|
||
|
|
std::memcpy(v, m_work2 + KeySize, OutSize);
|
||
|
|
}
|
||
|
|
public:
|
||
|
|
constexpr CtrDrbg() = default;
|
||
|
|
|
||
|
|
void Initialize(const void *entropy, size_t entropy_size, const void *nonce, size_t nonce_size, const void *personalization, size_t personalization_size) {
|
||
|
|
/* Handle init. */
|
||
|
|
if constexpr (UseDerivation) {
|
||
|
|
this->DeriveSeed(m_work1, entropy, entropy_size, nonce, nonce_size, personalization, personalization_size);
|
||
|
|
} else {
|
||
|
|
AMS_ASSERT(entropy_size == SeedSize);
|
||
|
|
AMS_ASSERT(nonce_size == 0);
|
||
|
|
AMS_ASSERT(personalization_size <= SeedSize);
|
||
|
|
AMS_UNUSED(entropy_size, nonce, nonce_size);
|
||
|
|
|
||
|
|
std::memcpy(m_work1, entropy, SeedSize);
|
||
|
|
Xor(m_work1, personalization, personalization_size);
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Clear key/v. */
|
||
|
|
std::memset(m_key, 0, sizeof(m_key));
|
||
|
|
std::memset(m_v, 0, sizeof(m_v));
|
||
|
|
|
||
|
|
/* Set key/v. */
|
||
|
|
this->UpdateStates(m_key, m_v, m_work1);
|
||
|
|
|
||
|
|
/* Set reseed counter. */
|
||
|
|
m_reseed_counter = 1;
|
||
|
|
}
|
||
|
|
|
||
|
|
void Reseed(const void *entropy, size_t entropy_size, const void *addl, size_t addl_size) {
|
||
|
|
/* Handle init. */
|
||
|
|
if constexpr (UseDerivation) {
|
||
|
|
this->DeriveSeed(m_work1, entropy, entropy_size, addl, addl_size, nullptr, 0);
|
||
|
|
} else {
|
||
|
|
AMS_ASSERT(entropy_size == SeedSize);
|
||
|
|
AMS_ASSERT(addl_size <= SeedSize);
|
||
|
|
AMS_UNUSED(entropy_size);
|
||
|
|
|
||
|
|
std::memcpy(m_work1, entropy, SeedSize);
|
||
|
|
Xor(m_work1, addl, addl_size);
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Set key/v. */
|
||
|
|
this->UpdateStates(m_key, m_v, m_work1);
|
||
|
|
|
||
|
|
/* Set reseed counter. */
|
||
|
|
m_reseed_counter = 1;
|
||
|
|
}
|
||
|
|
|
||
|
|
bool Generate(void *out, size_t size, const void *addl, size_t addl_size) {
|
||
|
|
/* Check that the request is small enough. */
|
||
|
|
if (size > RequestSizeMax) {
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Check if we need reseed. */
|
||
|
|
if (m_reseed_counter > ReseedInterval) {
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Clear work buffer. */
|
||
|
|
std::memset(m_work1, 0, sizeof(m_work1));
|
||
|
|
|
||
|
|
/* Process additional input, if we have any. */
|
||
|
|
if (addl_size > 0) {
|
||
|
|
if constexpr (UseDerivation) {
|
||
|
|
this->DeriveSeed(m_work1, addl, addl_size, nullptr, 0, nullptr, 0);
|
||
|
|
} else {
|
||
|
|
AMS_ASSERT(addl_size <= SeedSize);
|
||
|
|
std::memcpy(m_work1, addl, addl_size);
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Set key/v. */
|
||
|
|
this->UpdateStates(m_key, m_v, m_work1);
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Get buffer and aligned size. */
|
||
|
|
u8 *out_8 = static_cast<u8 *>(out);
|
||
|
|
const size_t aligned_size = util::AlignDown(size, OutSize);
|
||
|
|
|
||
|
|
/* Generate ctr bytes. */
|
||
|
|
m_block_cipher.Initialize(m_key, KeySize);
|
||
|
|
for (size_t offset = 0; offset < aligned_size; offset += OutSize) {
|
||
|
|
Increment(m_v);
|
||
|
|
m_block_cipher.EncryptBlock(out_8 + offset, OutSize, m_v, OutSize);
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Handle any unaligned data. */
|
||
|
|
if (size > aligned_size) {
|
||
|
|
u8 temp[OutSize];
|
||
|
|
Increment(m_v);
|
||
|
|
m_block_cipher.EncryptBlock(temp, sizeof(temp), m_v, OutSize);
|
||
|
|
std::memcpy(out_8 + aligned_size, temp, size - aligned_size);
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Set key/v. */
|
||
|
|
this->UpdateStates(m_key, m_v, m_work1);
|
||
|
|
|
||
|
|
/* Increment reseed counter. */
|
||
|
|
++m_reseed_counter;
|
||
|
|
return true;
|
||
|
|
}
|
||
|
|
};
|
||
|
|
|
||
|
|
}
|