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crypto: Implement BigNum/ExpMod

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This commit is contained in:
Michael Scire 2020-02-23 06:51:32 -08:00
parent 981166783b
commit d675aa3414
14 changed files with 1086 additions and 33 deletions
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15
libraries/config/common.mk
View file

@ -76,17 +76,12 @@ TARGET := $(notdir $(CURDIR))
BUILD := build
DATA := data
INCLUDES := include
SOURCES ?= source $(foreach d,$(filter-out source/arch source/board source,$(wildcard source/*)),$(if $(wildcard $d/.),$(call DIR_WILDCARD,$d) $d,))
ifneq ($(strip $(wildcard source/$(ATMOSPHERE_ARCH_DIR)/.*)),)
SOURCES += source/$(ATMOSPHERE_ARCH_DIR) $(call DIR_WILDCARD,source/$(ATMOSPHERE_ARCH_DIR))
endif
ifneq ($(strip $(wildcard source/$(ATMOSPHERE_BOARD_DIR)/.*)),)
SOURCES += source/$(ATMOSPHERE_BOARD_DIR) $(call DIR_WILDCARD,source/$(ATMOSPHERE_BOARD_DIR))
endif
ifneq ($(strip $(wildcard source/$(ATMOSPHERE_OS_DIR)/.*)),)
SOURCES += source/$(ATMOSPHERE_OS_DIR) $(call DIR_WILDCARD,source/$(ATMOSPHERE_OS_DIR))
endif
GENERAL_SOURCE_DIRS=$1 $(foreach d,$(filter-out $1/arch $1/board $1,$(wildcard $1/*)),$(if $(wildcard $d/.),$(call DIR_WILDCARD,$d) $d,))
SPECIFIC_SOURCE_DIRS=$(if $(wildcard $1/$2/.*),$1/$2 $(call DIR_WILDCARD,$1/$2),)
ALL_SOURCE_DIRS=$(call GENERAL_SOURCE_DIRS,$1) $(call SPECIFIC_SOURCE_DIRS,$1,$(ATMOSPHERE_ARCH_DIR)) $(call SPECIFIC_SOURCE_DIRS,$1,$(ATMOSPHERE_BOARD_DIR)) $(call SPECIFIC_SOURCE_DIRS,$1,$(ATMOSPHERE_OS_DIR))
SOURCES ?= $(call ALL_SOURCE_DIRS,source)
#---------------------------------------------------------------------------------
# Rules for compiling pre-compiled headers

2
libraries/libmesosphere/Makefile
View file

@ -14,6 +14,8 @@ CFLAGS := $(ATMOSPHERE_CFLAGS) $(SETTINGS) $(DEFINES) $(INCLUDE)
CXXFLAGS := $(CFLAGS) $(ATMOSPHERE_CXXFLAGS) -fno-use-cxa-atexit -flto
ASFLAGS := $(ATMOSPHERE_ASFLAGS) $(SETTINGS)
SOURCES += $(call ALL_SOURCE_DIRS,../libvapours/source)
LIBS :=
#---------------------------------------------------------------------------------

2
libraries/libstratosphere/Makefile
View file

@ -23,6 +23,8 @@ ASFLAGS := $(ATMOSPHERE_ASFLAGS) $(SETTINGS)
LDFLAGS := -specs=$(DEVKITPRO)/libnx/switch.specs $(SETTINGS) -Wl,-Map,$(notdir $*.map)
SOURCES += $(call ALL_SOURCE_DIRS,../libvapours/source)
LIBS := -lnx
#---------------------------------------------------------------------------------

2
libraries/libvapours/include/vapours/assert.hpp
View file

@ -19,7 +19,7 @@
namespace ams::impl {
template<typename... ArgTypes>
ALWAYS_INLINE void UnusedImpl(ArgTypes... args) {
constexpr ALWAYS_INLINE void UnusedImpl(ArgTypes... args) {
(static_cast<void>(args), ...);
}

2
libraries/libvapours/include/vapours/crypto.hpp
View file

@ -18,3 +18,5 @@
#include <vapours/defines.hpp>
#include <vapours/crypto/crypto_memory_compare.hpp>
#include <vapours/crypto/crypto_memory_clear.hpp>
#include <vapours/crypto/impl/crypto_bignum.hpp>

26
libraries/libvapours/include/vapours/crypto/crypto_memory_clear.hpp Normal file
View file

@ -0,0 +1,26 @@
/*
* Copyright (c) 2018-2020 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>
namespace ams::crypto {
void ClearMemory(void *mem, size_t size);
}

14
libraries/libvapours/include/vapours/crypto/crypto_memory_compare.hpp
View file

@ -19,20 +19,8 @@
#include <vapours/assert.hpp>
#include <vapours/util.hpp>
#ifdef ATMOSPHERE_ARCH_ARM64
#include <vapours/crypto/impl/crypto_memory_compare.arch.arm64.hpp>
#else
#error "Unknown architecture for crypto::IsSameBytes"
#endif
namespace ams::crypto {
inline bool IsSameBytes(const void *lhs, const void *rhs, size_t size) {
return impl::IsSameBytes(lhs, rhs, size);
}
bool IsSameBytes(const void *lhs, const void *rhs, size_t size);
}

163
libraries/libvapours/include/vapours/crypto/impl/crypto_bignum.hpp Normal file
View file

@ -0,0 +1,163 @@
/*
* Copyright (c) 2018-2020 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/crypto_memory_compare.hpp>
#include <vapours/crypto/crypto_memory_clear.hpp>
namespace ams::crypto::impl {
class BigNum {
NON_COPYABLE(BigNum);
NON_MOVEABLE(BigNum);
public:
using HalfWord = u16;
using Word = u32;
using DoubleWord = u64;
static constexpr size_t MaxBits = 4096;
static constexpr size_t BitsPerWord = sizeof(Word) * CHAR_BIT;
static constexpr Word MaxWord = std::numeric_limits<Word>::max();
static constexpr Word MaxHalfWord = std::numeric_limits<HalfWord>::max();
class WordAllocator {
NON_COPYABLE(WordAllocator);
NON_MOVEABLE(WordAllocator);
public:
class Allocation {
NON_COPYABLE(Allocation);
NON_MOVEABLE(Allocation);
private:
friend class WordAllocator;
private:
WordAllocator *allocator;
Word *buffer;
size_t count;
private:
constexpr ALWAYS_INLINE Allocation(WordAllocator *a, Word *w, size_t c) : allocator(a), buffer(w), count(c) { /* ... */ }
public:
ALWAYS_INLINE ~Allocation() { if (allocator) { allocator->Free(this->buffer, this->count); } }
constexpr ALWAYS_INLINE Word *GetBuffer() const { return this->buffer; }
constexpr ALWAYS_INLINE size_t GetCount() const { return this->count; }
constexpr ALWAYS_INLINE bool IsValid() const { return this->buffer != nullptr; }
};
friend class Allocation;
private:
Word *buffer;
size_t count;
size_t max_count;
size_t min_count;
private:
ALWAYS_INLINE void Free(void *words, size_t num) {
this->buffer -= num;
this->count += num;
AMS_ASSERT(words == this->buffer);
}
public:
constexpr ALWAYS_INLINE WordAllocator(Word *buf, size_t c) : buffer(buf), count(c), max_count(c), min_count(c) { /* ... */ }
ALWAYS_INLINE Allocation Allocate(size_t num) {
if (num <= this->count) {
Word *allocated = this->buffer;
this->buffer += num;
this->count -= num;
this->min_count = std::min(this->count, this->min_count);
return Allocation(this, allocated, num);
} else {
return Allocation(nullptr, nullptr, 0);
}
}
constexpr ALWAYS_INLINE size_t GetMaxUsedSize() const {
return (this->max_count - this->min_count) * sizeof(Word);
}
};
private:
Word *words;
size_t num_words;
size_t max_words;
private:
static void ImportImpl(Word *out, size_t out_size, const u8 *src, size_t src_size);
static void ExportImpl(u8 *out, size_t out_size, const Word *src, size_t src_size);
public:
constexpr BigNum() : words(), num_words(), max_words() { /* ... */ }
~BigNum() { /* ... */ }
constexpr void ReserveStatic(Word *buf, size_t capacity) {
this->words = buf;
this->max_words = capacity;
}
bool Import(const void *src, size_t src_size);
void Export(void *dst, size_t dst_size);
size_t GetSize() const;
bool IsZero() const {
return this->num_words == 0;
}
bool ExpMod(void *dst, const void *src, size_t size, const BigNum &exp, u32 *work_buf, size_t work_buf_size) const;
void ClearToZero();
void UpdateCount();
public:
/* Utility. */
static bool IsZero(const Word *w, size_t num_words);
static int Compare(const Word *lhs, const Word *rhs, size_t num_words);
static size_t CountWords(const Word *w, size_t num_words);
static size_t CountSignificantBits(Word w);
static void ClearToZero(Word *w, size_t num_words);
static void SetToWord(Word *w, size_t num_words, Word v);
static void Copy(Word *dst, const Word *src, size_t num_words);
/* Arithmetic. */
static bool ExpMod(Word *dst, const Word *src, const Word *exp, size_t exp_num_words, const Word *mod, size_t mod_num_words, WordAllocator *allocator);
static bool MultMod(Word *dst, const Word *src, const Word *mult, const Word *mod, size_t num_words, WordAllocator *allocator);
static bool Mod(Word *dst, const Word *src, size_t src_words, const Word *mod, size_t mod_words, WordAllocator *allocator);
static bool DivMod(Word *quot, Word *rem, const Word *top, size_t top_words, const Word *bot, size_t bot_words, WordAllocator *allocator);
static bool Mult(Word *dst, const Word *lhs, const Word *rhs, size_t num_words, WordAllocator *allocator);
static Word LeftShift(Word *dst, const Word *w, size_t num_words, const size_t shift);
static Word RightShift(Word *dst, const Word *w, size_t num_words, const size_t shift);
static Word Add(Word *dst, const Word *lhs, const Word *rhs, size_t num_words);
static Word Sub(Word *dst, const Word *lhs, const Word *rhs, size_t num_words);
static Word MultAdd(Word *dst, const Word *w, size_t num_words, Word mult);
static Word MultSub(Word *dst, const Word *w, const Word *v, size_t num_words, Word mult);
};
template<size_t Bits>
class StackBigNum : public BigNum {
public:
static constexpr size_t NumBits = Bits;
static constexpr size_t NumWords = util::AlignUp(NumBits, BitsPerWord) / BitsPerWord;
static constexpr size_t NumBytes = NumWords * sizeof(Word);
private:
Word word_buf[NumWords];
public:
constexpr StackBigNum() : word_buf() {
this->ReserveStatic(word_buf, NumWords);
}
};
}

4
libraries/libvapours/include/vapours/svc/svc_common.hpp
View file

@ -24,10 +24,8 @@ namespace ams::svc {
/* TODO: C++ style handle? */
#ifdef ATMOSPHERE_IS_STRATOSPHERE
using Handle = ::Handle;
#elif defined ATMOSPHERE_IS_MESOSPHERE
using Handle = u32;
#else
#error "Unknown target for svc::Handle"
using Handle = u32;
#endif
static constexpr size_t MaxWaitSynchronizationHandleCount = 0x40;

28
libraries/libvapours/source/crypto/crypto_memory_clear.cpp Normal file
View file

@ -0,0 +1,28 @@
/*
* Copyright (c) 2018-2020 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 {
void ClearMemory(void *_mem, size_t size) {
volatile u8 *mem = reinterpret_cast<volatile u8 *>(_mem);
for (size_t i = 0; i < size; i++) {
mem[i] = 0;
}
}
}

9
libraries/libvapours/include/vapours/crypto/impl/crypto_memory_compare.arch.arm64.hpp → libraries/libvapours/source/crypto/crypto_memory_compare.arch.arm64.cpp
View file

@ -13,14 +13,11 @@
* 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>
#pragma once
#include <vapours/defines.hpp>
#include <vapours/util.hpp>
namespace ams::crypto {
namespace ams::crypto::impl {
inline bool IsSameBytes(const void *lhs, const void *rhs, size_t size) {
bool IsSameBytes(const void *lhs, const void *rhs, size_t size) {
bool result;
u8 xor_acc, ltmp, rtmp;
size_t index;

148
libraries/libvapours/source/crypto/impl/crypto_bignum.cpp Normal file
View file

@ -0,0 +1,148 @@
/*
* Copyright (c) 2018-2020 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 {
void BigNum::ImportImpl(Word *out, size_t out_size, const u8 *src, size_t src_size) {
size_t octet_ofs = src_size;
size_t word_ofs = 0;
/* Parse octets into words. */
while (word_ofs < out_size && octet_ofs > 0) {
Word w = 0;
for (size_t shift = 0; octet_ofs > 0 && shift < BITSIZEOF(Word); shift += BITSIZEOF(u8)) {
w |= static_cast<Word>(src[--octet_ofs]) << shift;
}
out[word_ofs++] = w;
}
/* Zero-fill upper words. */
while (word_ofs < out_size) {
out[word_ofs++] = 0;
}
}
void BigNum::ExportImpl(u8 *out, size_t out_size, const Word *src, size_t src_size) {
size_t octet_ofs = out_size;
/* Parse words into octets. */
for (size_t word_ofs = 0; word_ofs < src_size && octet_ofs > 0; word_ofs++) {
const Word w = src[word_ofs];
for (size_t shift = 0; octet_ofs > 0 && shift < BITSIZEOF(Word); shift += BITSIZEOF(u8)) {
out[--octet_ofs] = static_cast<u8>(w >> shift);
}
}
/* Zero-clear remaining octets. */
while (octet_ofs > 0) {
out[--octet_ofs] = 0;
}
}
size_t BigNum::GetSize() const {
if (this->num_words == 0) {
return 0;
}
static_assert(sizeof(Word) == 4);
size_t size = this->num_words * sizeof(Word);
const Word last = this->words[this->num_words - 1];
AMS_ASSERT(last != 0);
if (last >= 0x01000000u) {
return size - 0;
} else if (last >= 0x00010000u) {
return size - 1;
} else if (last >= 0x00000100u) {
return size - 2;
} else {
return size - 3;
}
}
bool BigNum::Import(const void *src, size_t src_size) {
AMS_ASSERT((src != nullptr) || (src_size != 0));
/* Ignore leading zeroes. */
const u8 *data = static_cast<const u8 *>(src);
while (src_size > 0 && *data == 0) {
++data;
--src_size;
}
/* Ensure we have space for the number. */
AMS_ASSERT(src_size <= this->max_words * sizeof(Word));
if (AMS_UNLIKELY(!(src_size <= this->max_words * sizeof(Word)))) {
return false;
}
/* Import. */
this->num_words = util::AlignUp(src_size, sizeof(Word)) / sizeof(Word);
ImportImpl(this->words, this->max_words, data, src_size);
return true;
}
void BigNum::Export(void *dst, size_t dst_size) {
AMS_ASSERT(dst_size >= this->GetSize());
ExportImpl(static_cast<u8 *>(dst), dst_size, this->words, this->num_words);
}
bool BigNum::ExpMod(void *dst, const void *src, size_t size, const BigNum &exp, u32 *work_buf, size_t work_buf_size) const {
/* Can't exponentiate with or about zero. */
if (this->IsZero() || exp.IsZero()) {
return false;
}
AMS_ASSERT(size == this->GetSize());
/* Create an allocator. */
WordAllocator allocator(work_buf, work_buf_size / sizeof(Word));
ON_SCOPE_EXIT { ClearMemory(work_buf, allocator.GetMaxUsedSize()); };
/* Create a BigNum for the signature. */
BigNum signature;
auto signature_words = allocator.Allocate(size / sizeof(Word));
if (!signature_words.IsValid()) {
return false;
}
/* Import data for the signature. */
signature.ReserveStatic(signature_words.GetBuffer(), signature_words.GetCount());
if (!signature.Import(src, size)) {
return false;
}
/* Perform the exponentiation. */
if (!ExpMod(signature.words, signature.words, exp.words, exp.num_words, this->words, this->num_words, std::addressof(allocator))) {
return false;
}
/* We succeeded, so export. */
signature.UpdateCount();
signature.Export(dst, size);
return true;
}
void BigNum::ClearToZero() {
std::memset(this->words, 0, this->num_words * sizeof(Word));
}
void BigNum::UpdateCount() {
this->num_words = CountWords(this->words, this->max_words);
}
}

425
libraries/libvapours/source/crypto/impl/crypto_bignum_operations.cpp Normal file
View file

@ -0,0 +1,425 @@
/*
* Copyright (c) 2018-2020 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 {
constexpr ALWAYS_INLINE BigNum::Word GetTop2Bits(BigNum::Word w) {
return (w >> (BigNum::BitsPerWord - 2)) & 0x3u;
}
constexpr ALWAYS_INLINE void MultWord(BigNum::Word *dst, BigNum::Word lhs, BigNum::Word rhs) {
static_assert(sizeof(BigNum::DoubleWord) == sizeof(BigNum::Word) * 2);
BigNum::DoubleWord result = static_cast<BigNum::DoubleWord>(lhs) * static_cast<BigNum::DoubleWord>(rhs);
dst[0] = static_cast<BigNum::Word>(result & ~BigNum::Word());
dst[1] = static_cast<BigNum::Word>(result >> BITSIZEOF(BigNum::Word));
}
constexpr ALWAYS_INLINE BigNum::HalfWord GetUpperHalf(BigNum::Word word) {
static_assert(sizeof(BigNum::Word) == sizeof(BigNum::HalfWord) * 2);
return static_cast<BigNum::HalfWord>((word >> BITSIZEOF(BigNum::HalfWord)) & ~BigNum::HalfWord());
}
constexpr ALWAYS_INLINE BigNum::HalfWord GetLowerHalf(BigNum::Word word) {
static_assert(sizeof(BigNum::Word) == sizeof(BigNum::HalfWord) * 2);
return static_cast<BigNum::HalfWord>(word & ~BigNum::HalfWord());
}
constexpr ALWAYS_INLINE BigNum::Word ToUpperHalf(BigNum::HalfWord half) {
static_assert(sizeof(BigNum::Word) == sizeof(BigNum::HalfWord) * 2);
return static_cast<BigNum::Word>(half) << BITSIZEOF(BigNum::HalfWord);
}
constexpr ALWAYS_INLINE BigNum::Word ToLowerHalf(BigNum::HalfWord half) {
static_assert(sizeof(BigNum::Word) == sizeof(BigNum::HalfWord) * 2);
return static_cast<BigNum::Word>(half);
}
constexpr ALWAYS_INLINE BigNum::Word DivWord(const BigNum::Word *w, BigNum::Word div) {
using Word = BigNum::Word;
using HalfWord = BigNum::HalfWord;
Word work[2] = { w[0], w[1] };
HalfWord r_hi = 0, r_lo = 0;
HalfWord d_hi = GetUpperHalf(div);
HalfWord d_lo = GetLowerHalf(div);
if (d_hi == BigNum::MaxHalfWord) {
r_hi = GetUpperHalf(work[1]);
} else {
r_hi = GetLowerHalf(work[1] / (d_hi + 1));
}
{
const Word hh = static_cast<Word>(r_hi) * static_cast<Word>(d_hi);
const Word hl = static_cast<Word>(r_hi) * static_cast<Word>(d_lo);
const Word uhl = ToUpperHalf(static_cast<HalfWord>(hl));
if ((work[0] -= uhl) > (BigNum::MaxWord - uhl)) {
work[1]--;
}
work[1] -= GetUpperHalf(hl);
work[1] -= hh;
const Word udl = ToUpperHalf(d_lo);
while (work[1] > d_hi || (work[1] == d_hi && work[0] >= udl)) {
if ((work[0] -= udl) > (BigNum::MaxWord - udl)) {
work[1]--;
}
work[1] -= d_hi;
r_hi++;
}
}
if (d_hi == BigNum::MaxHalfWord) {
r_lo = GetLowerHalf(work[1]);
} else {
r_lo = GetLowerHalf((ToUpperHalf(static_cast<HalfWord>(work[1])) + GetUpperHalf(work[0])) / (d_hi + 1));
}
{
const Word ll = static_cast<Word>(r_lo) * static_cast<Word>(d_lo);
const Word lh = static_cast<Word>(r_lo) * static_cast<Word>(d_hi);
if ((work[0] -= ll) > (BigNum::MaxWord - ll)) {
work[1]--;
}
const Word ulh = ToUpperHalf(static_cast<HalfWord>(lh));
if ((work[0] -= ulh) > (BigNum::MaxWord - ulh)) {
work[1]--;
}
work[1] -= GetUpperHalf(lh);
while ((work[1] > 0) || (work[1] == 0 && work[0] >= div)) {
if ((work[0] -= div) > (BigNum::MaxWord - div)) {
work[1]--;
}
r_lo++;
}
}
return ToUpperHalf(r_hi) + r_lo;
}
}
bool BigNum::IsZero(const Word *w, size_t num_words) {
for (size_t i = 0; i < num_words; i++) {
if (w[i]) {
return false;
}
}
return true;
}
int BigNum::Compare(const Word *lhs, const Word *rhs, size_t num_words) {
for (s32 i = static_cast<s32>(num_words) - 1; i >= 0; i--) {
if (lhs[i] > rhs[i]) {
return 1;
} else if (lhs[i] < rhs[i]) {
return -1;
}
}
return 0;
}
size_t BigNum::CountWords(const Word *w, size_t num_words) {
s32 i = static_cast<s32>(num_words) - 1;
while (i >= 0 && !w[i]) {
i--;
}
return i + 1;
}
size_t BigNum::CountSignificantBits(Word w) {
size_t i;
for (i = 0; i < BitsPerWord && w != 0; i++) {
w >>= 1;
}
return i;
}
void BigNum::ClearToZero(Word *w, size_t num_words) {
for (size_t i = 0; i < num_words; i++) {
w[i] = 0;
}
}
void BigNum::SetToWord(Word *w, size_t num_words, Word v) {
ClearToZero(w, num_words);
w[0] = v;
}
void BigNum::Copy(Word *dst, const Word *src, size_t num_words) {
for (size_t i = 0; i < num_words; i++) {
dst[i] = src[i];
}
}
BigNum::Word BigNum::LeftShift(Word *dst, const Word *w, size_t num_words, const size_t shift) {
if (shift >= BitsPerWord) {
return 0;
}
const size_t invshift = BitsPerWord - shift;
Word carry = 0;
for (size_t i = 0; i < num_words; i++) {
const Word cur = w[i];
dst[i] = (cur << shift) | carry;
carry = shift ? (cur >> invshift) : 0;
}
return carry;
}
BigNum::Word BigNum::RightShift(Word *dst, const Word *w, size_t num_words, const size_t shift) {
if (shift >= BitsPerWord) {
return 0;
}
const size_t invshift = BitsPerWord - shift;
Word carry = 0;
for (s32 i = static_cast<s32>(num_words) - 1; i >= 0; i--) {
const Word cur = w[i];
dst[i] = (cur >> shift) | carry;
carry = shift ? (cur << invshift) : 0;
}
return carry;
}
BigNum::Word BigNum::MultSub(Word *dst, const Word *w, const Word *v, size_t num_words, Word mult) {
/* If multiplying by zero, nothing to do. */
if (mult == 0) {
return 0;
}
Word borrow = 0, work[2];
for (size_t i = 0; i < num_words; i++) {
/* Multiply, calculate borrow for next. */
MultWord(work, mult, v[i]);
if ((dst[i] = (w[i] - borrow)) > (MaxWord - borrow)) {
borrow = 1;
} else {
borrow = 0;
}
if ((dst[i] -= work[0]) > (MaxWord - work[0])) {
borrow++;
}
borrow += work[1];
}
return borrow;
}
bool BigNum::ExpMod(Word *dst, const Word *src, const Word *exp, size_t exp_words, const Word *mod, size_t mod_words, WordAllocator *allocator) {
/* Nintendo uses an algorithm that relies on powers of exp. */
bool needs_exp[4] = {};
if (exp_words > 1) {
needs_exp[2] = true;
needs_exp[3] = true;
} else {
Word exp_w = exp[0];
for (size_t i = 0; i < BitsPerWord / 2; i++) {
/* Nintendo at each step determines needed exponent from a pair of two bits. */
needs_exp[exp_w & 0x3u] = true;
exp_w >>= 2;
}
if (needs_exp[3]) {
needs_exp[2] = true;
}
}
/* Allocate space for powers 1, 2, 3. */
auto power_1 = allocator->Allocate(mod_words);
auto power_2 = allocator->Allocate(mod_words);
auto power_3 = allocator->Allocate(mod_words);
if (!(power_1.IsValid() && power_2.IsValid() && power_3.IsValid())) {
return false;
}
decltype(power_1)* powers[3] = { &power_1, &power_2, &power_3 };
/* Set the powers of src. */
Copy(power_1.GetBuffer(), src, mod_words);
if (needs_exp[2]) {
if (!MultMod(power_2.GetBuffer(), power_1.GetBuffer(), src, mod, mod_words, allocator)) {
return false;
}
}
if (needs_exp[3]) {
if (!MultMod(power_3.GetBuffer(), power_2.GetBuffer(), src, mod, mod_words, allocator)) {
return false;
}
}
/* Allocate space to work. */
auto work = allocator->Allocate(mod_words);
if (!work.IsValid()) {
return false;
}
SetToWord(work.GetBuffer(), work.GetCount(), 1);
/* Ensure we're working with the correct exponent word count. */
exp_words = CountWords(exp, exp_words);
for (s32 i = static_cast<s32>(exp_words - 1); i >= 0; i--) {
Word cur_word = exp[i];
size_t cur_bits = BitsPerWord;
/* Remove leading zeroes in first word. */
if (i == static_cast<s32>(exp_words - 1)) {
while (!GetTop2Bits(cur_word)) {
cur_word <<= 2;
cur_bits -= 2;
}
}
/* Compute current modular multiplicative step. */
for (size_t j = 0; j < cur_bits; j += 2, cur_word <<= 2) {
/* Exponentiate current work to the 4th power. */
if (!MultMod(work.GetBuffer(), work.GetBuffer(), work.GetBuffer(), mod, mod_words, allocator)) {
return false;
}
if (!MultMod(work.GetBuffer(), work.GetBuffer(), work.GetBuffer(), mod, mod_words, allocator)) {
return false;
}
if (const Word top = GetTop2Bits(cur_word)) {
if (!MultMod(work.GetBuffer(), work.GetBuffer(), powers[top - 1]->GetBuffer(), mod, mod_words, allocator)) {
return false;
}
}
}
}
/* Copy work to output. */
Copy(dst, work.GetBuffer(), mod_words);
return true;
}
bool BigNum::MultMod(Word *dst, const Word *src, const Word *mult, const Word *mod, size_t num_words, WordAllocator *allocator) {
/* Allocate work. */
auto work = allocator->Allocate(2 * num_words);
if (!work.IsValid()) {
return false;
}
/* Multiply. */
if (!Mult(work.GetBuffer(), src, mult, num_words, allocator)) {
return false;
}
/* Mod. */
if (!Mod(dst, work.GetBuffer(), 2 * num_words, mod, num_words, allocator)) {
return false;
}
return true;
}
bool BigNum::Mod(Word *dst, const Word *src, size_t src_words, const Word *mod, size_t mod_words, WordAllocator *allocator) {
/* Allocate work. */
auto work = allocator->Allocate(src_words);
if (!work.IsValid()) {
return false;
}
if (!DivMod(work.GetBuffer(), dst, src, src_words, mod, mod_words, allocator)) {
return false;
}
return true;
}
bool BigNum::DivMod(Word *quot, Word *rem, const Word *top, size_t top_words, const Word *bot, size_t bot_words, WordAllocator *allocator) {
/* Allocate work. */
auto top_work = allocator->Allocate(top_words + 1);
auto bot_work = allocator->Allocate(bot_words);
if (!(top_work.IsValid() && bot_work.IsValid())) {
return false;
}
/* Prevent division by zero. */
size_t bot_work_words = CountWords(bot, bot_words);
if (bot_work_words == 0) {
return false;
}
ClearToZero(quot, top_words);
ClearToZero(top_work.GetBuffer(), bot_work_words);
/* Align to edges. */
const size_t shift = BitsPerWord - CountSignificantBits(bot[bot_work_words - 1]);
top_work.GetBuffer()[top_words] = LeftShift(top_work.GetBuffer(), top, top_words, shift);
LeftShift(bot_work.GetBuffer(), bot, bot_work_words, shift);
const Word tb = bot_work.GetBuffer()[bot_work_words - 1];
/* Repeatedly div + sub. */
for (s32 i = (top_words - bot_work_words); i >= 0; i--) {
Word cur_word;
if (tb == MaxWord) {
cur_word = top_work.GetBuffer()[i + bot_work_words];
} else {
cur_word = DivWord(top_work.GetBuffer() + i + bot_work_words - 1, tb + 1);
}
top_work.GetBuffer()[i + bot_work_words] -= MultSub(top_work.GetBuffer() + i, top_work.GetBuffer() + i, bot_work.GetBuffer(), bot_work_words, cur_word);
while (top_work.GetBuffer()[i + bot_work_words] || Compare(top_work.GetBuffer() + i, bot_work.GetBuffer(), bot_work_words) >= 0) {
cur_word++;
top_work.GetBuffer()[i + bot_work_words] -= Sub(top_work.GetBuffer() + i, top_work.GetBuffer() + i, bot_work.GetBuffer(), bot_work_words);
}
quot[i] = cur_word;
}
/* Calculate remainder. */
ClearToZero(rem, bot_words);
RightShift(rem, top_work.GetBuffer(), bot_work_words, shift);
return true;
}
bool BigNum::Mult(Word *dst, const Word *lhs, const Word *rhs, size_t num_words, WordAllocator *allocator) {
/* Allocate work. */
auto work = allocator->Allocate(2 * num_words);
if (!work.IsValid()) {
return false;
}
ClearToZero(work.GetBuffer(), work.GetCount());
/* Repeatedly add and multiply. */
const size_t lhs_words = CountWords(lhs, num_words);
const size_t rhs_words = CountWords(rhs, num_words);
for (size_t i = 0; i < lhs_words; i++) {
work.GetBuffer()[i + rhs_words] += MultAdd(work.GetBuffer() + i, rhs, rhs_words, lhs[i]);
}
/* Copy to output. */
Copy(dst, work.GetBuffer(), work.GetCount());
return true;
}
}

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@ -0,0 +1,279 @@
/*
* Copyright (c) 2018-2020 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/>.
*/
/* ams::crypto::impl::BigNum::Add(Word *dst, const Word *lhs, const Word *rhs, size_t num_words) */
.section .text._ZN3ams6crypto4impl6BigNum3AddEPjPKjS5_m, "ax", %progbits
.global _ZN3ams6crypto4impl6BigNum3AddEPjPKjS5_m
.type _ZN3ams6crypto4impl6BigNum3AddEPjPKjS5_m, %function
.balign 0x10
_ZN3ams6crypto4impl6BigNum3AddEPjPKjPKjm:
/* Check if we have anything to do at all. */
msr nzcv, xzr
cbz x3, 7f
/* Save registers. */
stp x16, x17, [sp, #-16]!
stp xzr, x19, [sp, #-16]!
stp x20, x21, [sp, #-16]!
/* Check if we have less than 16 words to process. */
lsr x20, x3, #4
cbz x20, 2f
sub x3, x3, x20, lsl #4
1: /* Process 16 words at a time. */
/* NOTE: Nintendo uses X18 here, we will use X21 for EL1+ compat. */
ldp x4, x5, [x1], #16
ldp x12, x13, [x2], #16
ldp x6, x7, [x1], #16
ldp x14, x15, [x2], #16
ldp x8, x9, [x1], #16
ldp x16, x17, [x2], #16
ldp x10, x11, [x1], #16
ldp x21, x19, [x2], #16
adcs x4, x4, x12
adcs x5, x5, x13
stp x4, x5, [x0], #16
adcs x6, x6, x14
adcs x7, x7, x15
stp x6, x7, [x0], #16
adcs x8, x8, x16
adcs x9, x9, x17
stp x8, x9, [x0], #16
adcs x10, x10, x21
adcs x11, x11, x19
stp x10, x11, [x0], #16
sub x20, x20, #1
cbnz x20, 1b
2: /* We have less than 16 words to process. */
lsr x15, x3, #2
cbz x15, 4f
sub x3, x3, x15, lsl #2
3: /* Process 4 words at a time. */
ldp x4, x5, [x1], #16
ldp x8, x9, [x2], #16
sub x15, x15, #1
adcs x4, x4, x8
adcs x5, x5, x9
stp x4, x5, [x0], #16
cbnz x15, 3b
4: /* We have less than 4 words to process. */
cbz x3, 6f
5: /* Process 1 word at a time. */
ldr w4, [x1], #4
ldr w8, [x2], #4
adcs w4, w4, w8
str w4, [x0], #4
sub x3, x3, #1
cbnz x3, 5b
6: /* Restore registers we used while adding. */
ldp x20, x21, [sp], #16
ldp xzr, x19, [sp], #16
ldp x16, x17, [sp], #16
7: /* We're done. */
adc x0, xzr, xzr
ret
/* ams::crypto::impl::BigNum::Sub(Word *dst, const Word *lhs, const Word *rhs, size_t num_words) */
.section .text._ZN3ams6crypto4impl6BigNum3SubEPjPKjS5_m, "ax", %progbits
.global _ZN3ams6crypto4impl6BigNum3SubEPjPKjS5_m
.type _ZN3ams6crypto4impl6BigNum3SubEPjPKjS5_m, %function
.balign 0x10
_ZN3ams6crypto4impl6BigNum3SubEPjPKjS5_m:
/* Check if we have anything to do at all. */
mov x4, #0x20000000
msr nzcv, x4
cbz x3, 7f
/* Save registers. */
stp x16, x17, [sp, #-16]!
stp xzr, x19, [sp, #-16]!
stp x20, x21, [sp, #-16]!
/* Check if we have less than 16 words to process. */
lsr x20, x3, #4
cbz x20, 2f
sub x3, x3, x20, lsl #4
1: /* Process 16 words at a time. */
/* NOTE: Nintendo uses X18 here, we will use X21 for EL1+ compat. */
ldp x4, x5, [x1], #16
ldp x12, x13, [x2], #16
ldp x6, x7, [x1], #16
ldp x14, x15, [x2], #16
ldp x8, x9, [x1], #16
ldp x16, x17, [x2], #16
ldp x10, x11, [x1], #16
ldp x21, x19, [x2], #16
sbcs x4, x4, x12
sbcs x5, x5, x13
stp x4, x5, [x0], #16
sbcs x6, x6, x14
sbcs x7, x7, x15
stp x6, x7, [x0], #16
sbcs x8, x8, x16
sbcs x9, x9, x17
stp x8, x9, [x0], #16
sbcs x10, x10, x21
sbcs x11, x11, x19
stp x10, x11, [x0], #16
sub x20, x20, #1
cbnz x20, 1b
2: /* We have less than 16 words to process. */
lsr x15, x3, #2
cbz x15, 4f
sub x3, x3, x15, lsl #2
3: /* Process 4 words at a time. */
ldp x4, x5, [x1], #16
ldp x8, x9, [x2], #16
sub x15, x15, #1
sbcs x4, x4, x8
sbcs x5, x5, x9
stp x4, x5, [x0], #16
cbnz x15, 3b
4: /* We have less than 4 words to process. */
cbz x3, 6f
5: /* Process 1 word at a time. */
ldr w4, [x1], #4
ldr w8, [x2], #4
sbcs w4, w4, w8
str w4, [x0], #4
sub x3, x3, #1
cbnz x3, 5b
6: /* Restore registers we used while adding. */
ldp x20, x21, [sp], #16
ldp xzr, x19, [sp], #16
ldp x16, x17, [sp], #16
7: /* We're done. */
cinc x0, xzr, cc
ret
/* ams::crypto::impl::BigNum::MultAdd(Word *dst, const Word *w, size_t num_words, Word mult) */
.section .text._ZN3ams6crypto4impl6BigNum7MultAddEPjPKjmj, "ax", %progbits
.global _ZN3ams6crypto4impl6BigNum7MultAddEPjPKjmj
.type _ZN3ams6crypto4impl6BigNum7MultAddEPjPKjmj, %function
.balign 0x10
_ZN3ams6crypto4impl6BigNum7MultAddEPjPKjmj:
/* Check if we have anything to do at all. */
mov x15, xzr
cbz x2, 5f
/* Check if we have less than four words to process. */
lsr x6, x2, #2
cbz x6, 2f
/* We have more than four words to process. */
sub x2, x2, x6, lsl #2
stp x16, x17, [sp, #-16]!
1: /* Loop processing four words at a time. */
ldp w4, w5, [x1], #8
ldp w16, w7, [x1], #8
ldp w8, w9, [x0]
ldp w10, w11, [x0, #8]
umaddl x4, w3, w4, x8
umaddl x5, w3, w5, x9
umaddl x16, w3, w16, x10
umaddl x7, w3, w7, x11
add x12, x4, x15, lsr #32
add x13, x5, x12, lsr #32
stp w12, w13, [x0], #8
add x14, x16, x13, lsr #32
add x15, x7, x14, lsr #32
stp w14, w15, [x0], #8
sub x6, x6, #1
cbnz x6, 1b
ldp x16, x17, [sp], #16
2: /* We have less than four words. Check if we have less than two. */
lsr x6, x2, #1
cbz x6, 4f
/* We have more than two words to process. */
sub x2, x2, x6, lsl #1
3: /* Loop processing two words at a time. */
ldp w4, w5, [x1], #8
ldp w8, w9, [x0]
umaddl x4, w3, w4, x8
umaddl x5, w3, w5, x9
sub x6, x6, #1
add x14, x4, x15, lsr #32
add x15, x5, x14, lsr #32
stp w14, w15, [x0], #8
cbnz x6, 3b
4: /* We have less than two words to process. */
cbz x2, 5f
/* We have one word to process. */
ldr w4, [x1], #4
ldr w8, [x0]
umaddl x4, w3, w4, x8
add x15, x4, x15, lsr #32
str w15, [x0], #4
5: /* We're done. */
lsr x0, x15, #32
ret