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Loader: Implement IPS/IPS32 patching.

This commit is contained in:
Michael Scire 2018-07-28 20:28:17 -07:00
parent c1fd2eda20
commit 0f5f3c2ad0

View file

@ -7,6 +7,8 @@
#include <switch.h>
#include "ldr_patcher.hpp"
/* IPS Patching adapted from Luma3DS (https://github.com/AuroraWright/Luma3DS/blob/master/sysmodules/loader/source/patcher.c) */
#define IPS_MAGIC "PATCH"
#define IPS_TAIL "EOF"
@ -43,21 +45,85 @@ static bool MatchesBuildId(const char *name, size_t name_len, const u8 *build_id
return memcmp(build_id, build_id_from_name, sizeof(build_id_from_name)) == 0;
}
static inline void PatchNsoByte(u8 *nso, size_t max_size, size_t offset, u8 val) {
/* TODO: Be smarter about this. */
if (sizeof(NsoUtils::NsoHeader) <= offset && offset < max_size) {
nso[offset - sizeof(NsoUtils::NsoHeader)] = val;
static void ApplyIpsPatch(u8 *mapped_nso, size_t mapped_size, bool is_ips32, FILE *f_ips) {
u8 buffer[4];
while (fread(buffer, is_ips32 ? 4 : 3, 1, f_ips) == 1) {
if (is_ips32 && memcmp(buffer, IPS32_TAIL, 4) == 0) {
break;
} else if (!is_ips32 && memcmp(buffer, IPS_TAIL, 3) == 0) {
break;
}
/* Offset of patch. */
u32 patch_offset;
if (is_ips32) {
patch_offset = (buffer[0] << 24) | (buffer[1] << 16) | (buffer[2] << 8) | buffer[3];
} else {
patch_offset = (buffer[0] << 16) | (buffer[1] << 8) | (buffer[2]);
}
/* Size of patch. */
if (fread(buffer, 2, 1, f_ips) != 1) {
break;
}
u32 patch_size = (buffer[0] << 8) | (buffer[1]);
/* Check for RLE encoding. */
if (patch_size == 0) {
/* Size of RLE. */
if (fread(buffer, 2, 1, f_ips) != 1) {
break;
}
u32 rle_size = (buffer[0] << 8) | (buffer[1]);
/* Value for RLE. */
if (fread(buffer, 1, 1, f_ips) != 1) {
break;
}
if (patch_offset < sizeof(NsoUtils::NsoHeader)) {
if (patch_offset + rle_size > sizeof(NsoUtils::NsoHeader)) {
u32 diff = sizeof(NsoUtils::NsoHeader) - patch_offset;
patch_offset += diff;
rle_size -= diff;
goto IPS_RLE_PATCH_OFFSET_WITHIN_BOUNDS;
}
} else {
IPS_RLE_PATCH_OFFSET_WITHIN_BOUNDS:
patch_offset -= sizeof(NsoUtils::NsoHeader);
if (patch_offset + rle_size > mapped_size) {
rle_size = mapped_size - patch_offset;
}
memset(mapped_nso + patch_offset, buffer[0], rle_size);
}
} else {
if (patch_offset < sizeof(NsoUtils::NsoHeader)) {
if (patch_offset + patch_size > sizeof(NsoUtils::NsoHeader)) {
u32 diff = sizeof(NsoUtils::NsoHeader) - patch_offset;
patch_offset += diff;
patch_size -= diff;
fseek(f_ips, diff, SEEK_CUR);
goto IPS_DATA_PATCH_OFFSET_WITHIN_BOUNDS;
}
} else {
IPS_DATA_PATCH_OFFSET_WITHIN_BOUNDS:
patch_offset -= sizeof(NsoUtils::NsoHeader);
u32 read_size = patch_size;
if (patch_offset + read_size > mapped_size) {
read_size = mapped_size - patch_offset;
}
if (fread(mapped_nso + patch_offset, read_size, 1, f_ips) != 1) {
break;
}
if (patch_size > read_size) {
fseek(f_ips, patch_size - read_size, SEEK_CUR);
}
}
}
}
}
static void ApplyIpsPatch(u8 *mapped_nso, size_t mapped_size, FILE *ips) {
/* TODO */
}
static void ApplyIps32Patch(u8 *mapped_nso, size_t mapped_size, FILE *ips) {
/* TODO */
}
void PatchUtils::ApplyPatches(u64 title_id, const NsoUtils::NsoHeader *header, u8 *mapped_nso, size_t mapped_size) {
/* Inspect all patches from /<title>/exefs/patches/<*>/<*>.ips. */
char path[FS_MAX_PATH+1] = {0};
@ -87,9 +153,9 @@ void PatchUtils::ApplyPatches(u64 title_id, const NsoUtils::NsoHeader *header, u
u8 header[5];
if (fread(header, 5, 1, f_ips) == 1) {
if (memcmp(header, IPS_MAGIC, 5) == 0) {
ApplyIpsPatch(mapped_nso, mapped_size, f_ips);
ApplyIpsPatch(mapped_nso, mapped_size, false, f_ips);
} else if (memcmp(header, IPS32_MAGIC, 5) == 0) {
ApplyIps32Patch(mapped_nso, mapped_size, f_ips);
ApplyIps32Patch(mapped_nso, mapped_size, true, f_ips);
}
}
fclose(f_ips);