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Atmosphere/libraries/libvapours/source/crypto/impl/crypto_md5_impl.cpp
2021-10-29 17:38:44 -07:00

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/*
* 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/>.
*/
#include <vapours.hpp>
namespace ams::crypto::impl {
namespace {
struct Md5Constants {
static constexpr const u32 A = 0x67452301;
static constexpr const u32 B = 0xEFCDAB89;
static constexpr const u32 C = 0x98BADCFE;
static constexpr const u32 D = 0x10325476;
static constexpr const u32 T[] = {
0xD76AA478, 0xE8C7B756, 0x242070DB, 0xC1BDCEEE,
0xF57C0FAF, 0x4787C62A, 0xA8304613, 0xFD469501,
0x698098D8, 0x8B44F7AF, 0xFFFF5BB1, 0x895CD7BE,
0x6B901122, 0xFD987193, 0xA679438E, 0x49B40821,
0xF61E2562, 0xC040B340, 0x265E5A51, 0xE9B6C7AA,
0xD62F105D, 0x02441453, 0xD8A1E681, 0xE7D3FBC8,
0x21E1CDE6, 0xC33707D6, 0xF4D50D87, 0x455A14ED,
0xA9E3E905, 0xFCEFA3F8, 0x676F02D9, 0x8D2A4C8A,
0xFFFA3942, 0x8771F681, 0x6D9D6122, 0xFDE5380C,
0xA4BEEA44, 0x4BDECFA9, 0xF6BB4B60, 0xBEBFBC70,
0x289B7EC6, 0xEAA127FA, 0xD4EF3085, 0x04881D05,
0xD9D4D039, 0xE6DB99E5, 0x1FA27CF8, 0xC4AC5665,
0xF4292244, 0x432AFF97, 0xAB9423A7, 0xFC93A039,
0x655B59C3, 0x8F0CCC92, 0xFFEFF47D, 0x85845DD1,
0x6FA87E4F, 0xFE2CE6E0, 0xA3014314, 0x4E0811A1,
0xF7537E82, 0xBD3AF235, 0x2AD7D2BB, 0xEB86D391,
};
static constexpr u32 K[] = {
0x1, 0x6, 0xB, 0x0,
0x5, 0xA, 0xF, 0x4,
0x9, 0xE, 0x3, 0x8,
0xD, 0x2, 0x7, 0xC,
0x5, 0x8, 0xB, 0xE,
0x1, 0x4, 0x7, 0xA,
0xD, 0x0, 0x3, 0x6,
0x9, 0xC, 0xF, 0x2,
0x0, 0x7, 0xE, 0x5,
0xC, 0x3, 0xA, 0x1,
0x8, 0xF, 0x6, 0xD,
0x4, 0xB, 0x2, 0x9,
};
static constexpr u8 Padding[] = {
0x80
};
};
constexpr ALWAYS_INLINE u32 F(u32 x, u32 y, u32 z) { return (x & y) | ((~x) & z); }
constexpr ALWAYS_INLINE u32 G(u32 x, u32 y, u32 z) { return (x & z) | (y & (~z)); }
constexpr ALWAYS_INLINE u32 H(u32 x, u32 y, u32 z) { return x ^ y ^ z; }
constexpr ALWAYS_INLINE u32 I(u32 x, u32 y, u32 z) { return y ^ (x | (~z)); }
constexpr ALWAYS_INLINE u32 CalculateRound1(u32 a, u32 b, u32 c, u32 d, u32 x, u32 s, u32 t) { return b + util::RotateLeft<u32>(a + F(b, c, d) + x + t, s); }
constexpr ALWAYS_INLINE u32 CalculateRound2(u32 a, u32 b, u32 c, u32 d, u32 x, u32 s, u32 t) { return b + util::RotateLeft<u32>(a + G(b, c, d) + x + t, s); }
constexpr ALWAYS_INLINE u32 CalculateRound3(u32 a, u32 b, u32 c, u32 d, u32 x, u32 s, u32 t) { return b + util::RotateLeft<u32>(a + H(b, c, d) + x + t, s); }
constexpr ALWAYS_INLINE u32 CalculateRound4(u32 a, u32 b, u32 c, u32 d, u32 x, u32 s, u32 t) { return b + util::RotateLeft<u32>(a + I(b, c, d) + x + t, s); }
void Encode(u32 *dst, const u32 *src, size_t size) {
if constexpr (util::IsBigEndian()) {
for (size_t i = 0; i < size; i += sizeof(u32)) {
util::StoreLittleEndian(dst + i, src[i]);
}
} else {
std::memcpy(dst, src, size);
}
}
void Decode(u32 *dst, const u32 *src, size_t size) {
if constexpr (util::IsBigEndian()) {
for (size_t i = 0; i < size; i += sizeof(u32)) {
dst[i] = util::LoadLittleEndian(src + i);
}
} else {
std::memcpy(dst, src, size);
}
}
}
void Md5Impl::Initialize() {
/* Set constants. */
m_x.p.a = Md5Constants::A;
m_x.p.b = Md5Constants::B;
m_x.p.c = Md5Constants::C;
m_x.p.d = Md5Constants::D;
/* Set size. */
m_size = 0;
/* Set initialized. */
m_state = State_Initialized;
}
void Md5Impl::Update(const void *data, size_t size) {
/* Check pre-conditions. */
AMS_ASSERT(m_state == State_Initialized);
/* Determine how much we can process. */
const size_t work_idx = m_size % BlockSize;
const size_t work_remaining = BlockSize - work_idx;
/* Increment our size. */
m_size += size;
/* Copy in the data to our buffer, if we don't have a full block. */
if (work_remaining > size) {
if (size > 0) {
std::memcpy(m_y + work_idx, data, size);
}
return;
}
/* Copy what we can to complete our block. */
std::memcpy(m_y + work_idx, data, work_remaining);
/* Process the block. */
this->ProcessBlock();
/* Adjust size to account for what we've processed. */
size -= work_remaining;
/* Process as many full blocks as we can. */
const u8 *cur_block = static_cast<const u8 *>(data) + work_remaining;
for (size_t i = 0; i < size / BlockSize; ++i) {
std::memcpy(m_y, cur_block, BlockSize);
cur_block += BlockSize;
this->ProcessBlock();
}
/* Copy in any leftover data. */
if (const auto left = size % BlockSize; left > 0) {
std::memcpy(m_y, cur_block, left);
}
}
void Md5Impl::GetHash(void *dst, size_t size) {
/* Check pre-conditions. */
AMS_ASSERT(m_state == State_Initialized || m_state == State_Done);
AMS_ASSERT(size >= HashSize);
AMS_UNUSED(size);
/* If we need to, finish processing. */
if (m_state == State_Initialized) {
this->ProcessLastBlock();
m_state = State_Done;
}
/* Encode the result. */
Encode(static_cast<u32 *>(dst), m_x.state, HashSize);
}
void Md5Impl::ProcessBlock() {
/* Declare tracking pointers for rounds. */
u32 x[BlockSize / sizeof(u32)];
const u32 *p_t = Md5Constants::T;
const u32 *p_k = Md5Constants::K;
const u32 *p_x = x;
/* Extract current state. */
u32 a = m_x.p.a;
u32 b = m_x.p.b;
u32 c = m_x.p.c;
u32 d = m_x.p.d;
/* Decode the block into native endian. */
Decode(x, reinterpret_cast<const u32 *>(m_y), BlockSize);
/* Perform round 1. */
for (size_t i = 0; i < 4; ++i) {
a = CalculateRound1(a, b, c, d, *p_x++, 7, *p_t++);
d = CalculateRound1(d, a, b, c, *p_x++, 12, *p_t++);
c = CalculateRound1(c, d, a, b, *p_x++, 17, *p_t++);
b = CalculateRound1(b, c, d, a, *p_x++, 22, *p_t++);
}
/* Perform round 2. */
for (size_t i = 0; i < 4; ++i) {
a = CalculateRound2(a, b, c, d, x[*p_k++], 5, *p_t++);
d = CalculateRound2(d, a, b, c, x[*p_k++], 9, *p_t++);
c = CalculateRound2(c, d, a, b, x[*p_k++], 14, *p_t++);
b = CalculateRound2(b, c, d, a, x[*p_k++], 20, *p_t++);
}
/* Perform round 3. */
for (size_t i = 0; i < 4; ++i) {
a = CalculateRound3(a, b, c, d, x[*p_k++], 4, *p_t++);
d = CalculateRound3(d, a, b, c, x[*p_k++], 11, *p_t++);
c = CalculateRound3(c, d, a, b, x[*p_k++], 16, *p_t++);
b = CalculateRound3(b, c, d, a, x[*p_k++], 23, *p_t++);
}
/* Perform round 4. */
for (size_t i = 0; i < 4; ++i) {
a = CalculateRound4(a, b, c, d, x[*p_k++], 6, *p_t++);
d = CalculateRound4(d, a, b, c, x[*p_k++], 10, *p_t++);
c = CalculateRound4(c, d, a, b, x[*p_k++], 15, *p_t++);
b = CalculateRound4(b, c, d, a, x[*p_k++], 21, *p_t++);
}
/* Mix the result back into our state. */
m_x.p.a += a;
m_x.p.b += b;
m_x.p.c += c;
m_x.p.d += d;
}
void Md5Impl::ProcessLastBlock() {
/* Get bit count. */
const u64 bit_count = m_size * BITSIZEOF(u8);
/* Add padding byte unconditionally. */
this->Update(Md5Constants::Padding, sizeof(Md5Constants::Padding));
/* Determine remaining. */
size_t work_idx = m_size % BlockSize;
size_t work_remaining = BlockSize - work_idx;
/* We want to process 8000.....{bit count}. */
if (work_remaining < sizeof(u64)) {
std::memset(m_y + work_idx, 0, work_remaining);
this->ProcessBlock();
work_idx = 0;
work_remaining = BlockSize;
}
if (work_remaining > sizeof(u64)) {
std::memset(m_y + work_idx, 0, work_remaining - sizeof(u64));
}
util::StoreLittleEndian<u64>(reinterpret_cast<u64 *>(m_y + BlockSize - sizeof(u64)), bit_count);
this->ProcessBlock();
}
}