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Atmosphere/libraries/libstratosphere/source/patcher/patcher_api.cpp
2020-06-25 17:32:34 -07:00

284 lines
12 KiB
C++

/*
* 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 <stratosphere.hpp>
/* IPS Patching adapted from Luma3DS (https://github.com/AuroraWright/Luma3DS/blob/master/sysmodules/loader/source/patcher.c) */
namespace ams::patcher {
namespace {
/* Convenience definitions. */
constexpr const char IpsHeadMagic[5] = {'P', 'A', 'T', 'C', 'H'};
constexpr const char IpsTailMagic[3] = {'E', 'O', 'F'};
constexpr const char Ips32HeadMagic[5] = {'I', 'P', 'S', '3', '2'};
constexpr const char Ips32TailMagic[4] = {'E', 'E', 'O', 'F'};
constexpr const char *IpsFileExtension = ".ips";
constexpr size_t IpsFileExtensionLength = std::strlen(IpsFileExtension);
constexpr size_t ModuleIpsPatchLength = 2 * sizeof(ro::ModuleId) + IpsFileExtensionLength;
/* Global data. */
os::Mutex apply_patch_lock(false);
u8 g_patch_read_buffer[os::MemoryPageSize];
/* Helpers. */
inline u8 ConvertHexNybble(const char nybble) {
if ('0' <= nybble && nybble <= '9') {
return nybble - '0';
} else if ('a' <= nybble && nybble <= 'f') {
return nybble - 'a' + 0xa;
} else {
return nybble - 'A' + 0xA;
}
}
bool ParseModuleIdFromPath(ro::ModuleId *out_module_id, const char *name, size_t name_len, size_t extension_len) {
/* Validate name is hex module id. */
for (unsigned int i = 0; i < name_len - extension_len; i++) {
if (!std::isxdigit(static_cast<unsigned char>(name[i]))) {
return false;
}
}
/* Read module id from name. */
std::memset(out_module_id, 0, sizeof(*out_module_id));
for (unsigned int name_ofs = 0, id_ofs = 0; name_ofs < name_len - extension_len && id_ofs < sizeof(*out_module_id); id_ofs++) {
out_module_id->build_id[id_ofs] |= ConvertHexNybble(name[name_ofs++]) << 4;
out_module_id->build_id[id_ofs] |= ConvertHexNybble(name[name_ofs++]);
}
return true;
}
bool MatchesModuleId(const char *name, size_t name_len, size_t extension_len, const ro::ModuleId *module_id) {
/* Get module id. */
ro::ModuleId module_id_from_name;
if (!ParseModuleIdFromPath(&module_id_from_name, name, name_len, extension_len)) {
return false;
}
return std::memcmp(&module_id_from_name, module_id, sizeof(*module_id)) == 0;
}
bool IsIpsFileForModule(const char *name, const ro::ModuleId *module_id) {
const size_t name_len = std::strlen(name);
/* The path must be correct size for a build id (with trailing zeroes optionally trimmed) + ".ips". */
if (!(IpsFileExtensionLength < name_len && name_len <= ModuleIpsPatchLength)) {
return false;
}
/* The path must be an even number of characters to conform. */
if (!util::IsAligned(name_len, 2)) {
return false;
}
/* The path needs to end with .ips. */
if (std::strcmp(name + name_len - IpsFileExtensionLength, IpsFileExtension) != 0) {
return false;
}
/* The path needs to match the module id. */
return MatchesModuleId(name, name_len, IpsFileExtensionLength, module_id);
}
inline bool IsIpsTail(bool is_ips32, u8 *buffer) {
if (is_ips32) {
return std::memcmp(buffer, Ips32TailMagic, sizeof(Ips32TailMagic)) == 0;
} else {
return std::memcmp(buffer, IpsTailMagic, sizeof(IpsTailMagic)) == 0;
}
}
inline u32 GetIpsPatchOffset(bool is_ips32, u8 *buffer) {
if (is_ips32) {
return (buffer[0] << 24) | (buffer[1] << 16) | (buffer[2] << 8) | (buffer[3]);
} else {
return (buffer[0] << 16) | (buffer[1] << 8) | (buffer[2]);
}
}
inline u32 GetIpsPatchSize(bool is_ips32, u8 *buffer) {
return (buffer[0] << 8) | (buffer[1]);
}
void ApplyIpsPatch(u8 *mapped_module, size_t mapped_size, size_t protected_size, size_t offset, bool is_ips32, fs::FileHandle file) {
/* Validate offset/protected size. */
AMS_ABORT_UNLESS(offset <= protected_size);
s64 file_offset = sizeof(IpsHeadMagic);
auto ReadData = [&](void *dst, size_t size) ALWAYS_INLINE_LAMBDA {
R_ABORT_UNLESS(fs::ReadFile(file, file_offset, dst, size));
file_offset += size;
};
u8 buffer[sizeof(Ips32TailMagic)];
while (true) {
ReadData(buffer, is_ips32 ? sizeof(Ips32TailMagic) : sizeof(IpsTailMagic));
if (IsIpsTail(is_ips32, buffer)) {
break;
}
/* Offset of patch. */
u32 patch_offset = GetIpsPatchOffset(is_ips32, buffer);
/* Size of patch. */
ReadData(buffer, 2);
u32 patch_size = GetIpsPatchSize(is_ips32, buffer);
/* Check for RLE encoding. */
if (patch_size == 0) {
/* Size of RLE. */
ReadData(buffer, 2);
u32 rle_size = (buffer[0] << 8) | (buffer[1]);
/* Value for RLE. */
ReadData(buffer, 1);
/* Ensure we don't write to protected region. */
if (patch_offset < protected_size) {
if (patch_offset + rle_size > protected_size) {
const u32 diff = protected_size - patch_offset;
patch_offset += diff;
rle_size -= diff;
} else {
continue;
}
}
/* Adjust offset, if relevant. */
patch_offset -= offset;
/* Apply patch. */
if (patch_offset + rle_size > mapped_size) {
rle_size = mapped_size - patch_offset;
}
std::memset(mapped_module + patch_offset, buffer[0], rle_size);
} else {
/* Ensure we don't write to protected region. */
if (patch_offset < protected_size) {
if (patch_offset + patch_size > protected_size) {
const u32 diff = protected_size - patch_offset;
patch_offset += diff;
patch_size -= diff;
file_offset += diff;
} else {
file_offset += patch_size;
continue;
}
}
/* Adjust offset, if relevant. */
patch_offset -= offset;
/* Apply patch. */
u32 read_size = patch_size;
if (patch_offset + read_size > mapped_size) {
read_size = mapped_size - patch_offset;
}
{
size_t remaining = read_size;
size_t copy_offset = patch_offset;
while (remaining > 0) {
const size_t cur_read = std::min(remaining, sizeof(g_patch_read_buffer));
ReadData(g_patch_read_buffer, cur_read);
std::memcpy(mapped_module + copy_offset, g_patch_read_buffer, cur_read);
remaining -= cur_read;
copy_offset += cur_read;
}
}
if (patch_size > read_size) {
file_offset += patch_size - read_size;
}
}
}
}
}
void LocateAndApplyIpsPatchesToModule(const char *mount_name, const char *patch_dir_name, size_t protected_size, size_t offset, const ro::ModuleId *module_id, u8 *mapped_module, size_t mapped_size) {
/* Ensure only one thread tries to apply patches at a time. */
std::scoped_lock lk(apply_patch_lock);
/* Inspect all patches from /atmosphere/<patch_dir>/<*>/<*>.ips */
char path[fs::EntryNameLengthMax + 1];
std::snprintf(path, sizeof(path), "%s:/atmosphere/%s", mount_name, patch_dir_name);
const size_t patches_dir_path_len = std::strlen(path);
/* Open the patch directory. */
fs::DirectoryHandle patches_dir;
if (R_FAILED(fs::OpenDirectory(std::addressof(patches_dir), path, fs::OpenDirectoryMode_Directory))) {
return;
}
ON_SCOPE_EXIT { fs::CloseDirectory(patches_dir); };
/* Iterate over the patches directory to find patch subdirectories. */
while (true) {
/* Read the next entry. */
s64 count;
fs::DirectoryEntry entry;
if (R_FAILED(fs::ReadDirectory(std::addressof(count), std::addressof(entry), patches_dir, 1)) || count == 0) {
break;
}
/* Print the path for this directory. */
std::snprintf(path + patches_dir_path_len, sizeof(path) - patches_dir_path_len, "/%s", entry.name);
const size_t patch_dir_path_len = patches_dir_path_len + 1 + std::strlen(entry.name);
/* Open the patch directory. */
fs::DirectoryHandle patch_dir;
if (R_FAILED(fs::OpenDirectory(std::addressof(patch_dir), path, fs::OpenDirectoryMode_File))) {
continue;
}
ON_SCOPE_EXIT { fs::CloseDirectory(patch_dir); };
/* Iterate over files in the patch directory. */
while (true) {
if (R_FAILED(fs::ReadDirectory(std::addressof(count), std::addressof(entry), patch_dir, 1)) || count == 0) {
break;
}
/* Check if this file is an ips. */
if (!IsIpsFileForModule(entry.name, module_id)) {
continue;
}
/* Print the path for this file. */
std::snprintf(path + patch_dir_path_len, sizeof(path) - patch_dir_path_len, "/%s", entry.name);
/* Open the file. */
fs::FileHandle file;
if (R_FAILED(fs::OpenFile(std::addressof(file), path, fs::OpenMode_Read))) {
continue;
}
ON_SCOPE_EXIT { fs::CloseFile(file); };
/* Read the header. */
u8 header[sizeof(IpsHeadMagic)];
if (R_SUCCEEDED(fs::ReadFile(file, 0, header, sizeof(header)))) {
if (std::memcmp(header, IpsHeadMagic, sizeof(header)) == 0) {
ApplyIpsPatch(mapped_module, mapped_size, protected_size, offset, false, file);
} else if (std::memcmp(header, Ips32HeadMagic, sizeof(header)) == 0) {
ApplyIpsPatch(mapped_module, mapped_size, protected_size, offset, true, file);
}
}
}
}
}
}