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Atmosphere/libraries/libstratosphere/source/patcher/patcher_api.cpp
2020-02-22 23:05:14 -08:00

235 lines
10 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 <dirent.h>
#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;
/* 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(name[i]) == 0) {
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;
}
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, FILE *f_ips) {
/* Validate offset/protected size. */
AMS_ABORT_UNLESS(offset <= protected_size);
u8 buffer[sizeof(Ips32TailMagic)];
while (true) {
AMS_ABORT_UNLESS(fread(buffer, is_ips32 ? sizeof(Ips32TailMagic) : sizeof(IpsTailMagic), 1, f_ips) == 1);
if (IsIpsTail(is_ips32, buffer)) {
break;
}
/* Offset of patch. */
u32 patch_offset = GetIpsPatchOffset(is_ips32, buffer);
/* Size of patch. */
AMS_ABORT_UNLESS(fread(buffer, 2, 1, f_ips) == 1);
u32 patch_size = GetIpsPatchSize(is_ips32, buffer);
/* Check for RLE encoding. */
if (patch_size == 0) {
/* Size of RLE. */
AMS_ABORT_UNLESS(fread(buffer, 2, 1, f_ips) == 1);
u32 rle_size = (buffer[0] << 8) | (buffer[1]);
/* Value for RLE. */
AMS_ABORT_UNLESS(fread(buffer, 1, 1, f_ips) == 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;
fseek(f_ips, diff, SEEK_CUR);
} else {
fseek(f_ips, patch_size, SEEK_CUR);
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;
}
AMS_ABORT_UNLESS(fread(mapped_module + patch_offset, read_size, 1, f_ips) == 1);
if (patch_size > read_size) {
fseek(f_ips, patch_size - read_size, SEEK_CUR);
}
}
}
}
}
void LocateAndApplyIpsPatchesToModule(const char *patch_dir_name, size_t protected_size, size_t offset, const ro::ModuleId *module_id, u8 *mapped_module, size_t mapped_size) {
/* Inspect all patches from /atmosphere/<patch_dir>/<*>/<*>.ips */
char path[FS_MAX_PATH+1] = {0};
std::snprintf(path, sizeof(path) - 1, "sdmc:/atmosphere/%s", patch_dir_name);
DIR *patches_dir = opendir(path);
struct dirent *pdir_ent;
if (patches_dir != NULL) {
/* Iterate over the patches directory to find patch subdirectories. */
while ((pdir_ent = readdir(patches_dir)) != NULL) {
if (std::strcmp(pdir_ent->d_name, ".") == 0 || std::strcmp(pdir_ent->d_name, "..") == 0) {
continue;
}
std::snprintf(path, sizeof(path) - 1, "sdmc:/atmosphere/%s/%s", patch_dir_name, pdir_ent->d_name);
DIR *patch_dir = opendir(path);
struct dirent *ent;
if (patch_dir != NULL) {
/* Iterate over the patch subdirectory to find .ips patches. */
while ((ent = readdir(patch_dir)) != NULL) {
if (std::strcmp(ent->d_name, ".") == 0 || std::strcmp(ent->d_name, "..") == 0) {
continue;
}
size_t name_len = strlen(ent->d_name);
if (!(IpsFileExtensionLength < name_len && name_len <= ModuleIpsPatchLength)) {
continue;
}
if ((name_len & 1) != 0) {
continue;
}
if (std::strcmp(ent->d_name + name_len - IpsFileExtensionLength, IpsFileExtension) != 0) {
continue;
}
if (!MatchesModuleId(ent->d_name, name_len, IpsFileExtensionLength, module_id)) {
continue;
}
std::snprintf(path, sizeof(path) - 1, "sdmc:/atmosphere/%s/%s/%s", patch_dir_name, pdir_ent->d_name, ent->d_name);
FILE *f_ips = fopen(path, "rb");
if (f_ips == NULL) {
continue;
}
ON_SCOPE_EXIT { fclose(f_ips); };
u8 header[5];
if (fread(header, 5, 1, f_ips) == 1) {
if (std::memcmp(header, IpsHeadMagic, 5) == 0) {
ApplyIpsPatch(mapped_module, mapped_size, protected_size, offset, false, f_ips);
} else if (std::memcmp(header, Ips32HeadMagic, 5) == 0) {
ApplyIpsPatch(mapped_module, mapped_size, protected_size, offset, true, f_ips);
}
}
fclose(f_ips);
}
closedir(patch_dir);
}
}
closedir(patches_dir);
}
}
}