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Atmosphere/fusee/fusee-secondary/src/ips.c
Michael Scire 2f29bcef3a fusee: Fix IPS patching for KIPs. (closes #3).
2018-10-16 17:21:08 -07:00

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/*
* Copyright (c) 2018 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 <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <dirent.h>
#include <string.h>
#include <ctype.h>
#include "utils.h"
#include "se.h"
#include "lib/log.h"
#include "ips.h"
/* 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"
#define IPS32_MAGIC "IPS32"
#define IPS32_TAIL "EEOF"
/* Applies an IPS/IPS32 patch to memory, disregarding writes to the first prot_size bytes. */
static void apply_ips_patch(uint8_t *mem, size_t mem_size, size_t prot_size, bool is_ips32, FILE *f_ips) {
uint8_t 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. */
uint32_t 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;
}
uint32_t 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;
}
uint32_t rle_size = (buffer[0] << 8) | (buffer[1]);
/* Value for RLE. */
if (fread(buffer, 1, 1, f_ips) != 1) {
break;
}
if (patch_offset < prot_size) {
if (patch_offset + rle_size > prot_size) {
uint32_t diff = prot_size - patch_offset;
patch_offset += diff;
rle_size -= diff;
goto IPS_RLE_PATCH_OFFSET_WITHIN_BOUNDS;
}
} else {
IPS_RLE_PATCH_OFFSET_WITHIN_BOUNDS:
if (patch_offset + rle_size > mem_size) {
rle_size = mem_size - patch_offset;
}
memset(mem + patch_offset, buffer[0], rle_size);
}
} else {
uint32_t read_size;
if (patch_offset < prot_size) {
if (patch_offset + patch_size > prot_size) {
uint32_t diff = prot_size - patch_offset;
patch_offset += diff;
patch_size -= diff;
fseek(f_ips, diff, SEEK_CUR);
goto IPS_DATA_PATCH_OFFSET_WITHIN_BOUNDS;
} else {
fseek(f_ips, patch_size, SEEK_CUR);
}
} else {
IPS_DATA_PATCH_OFFSET_WITHIN_BOUNDS:
read_size = patch_size;
if (patch_offset + read_size > mem_size) {
read_size = mem_size - patch_offset;
}
if (fread(mem + patch_offset, read_size, 1, f_ips) != 1) {
break;
}
if (patch_size > read_size) {
fseek(f_ips, patch_size - read_size, SEEK_CUR);
}
}
}
}
}
static inline uint8_t hex_nybble_to_u8(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;
}
}
static bool name_matches_hash(const char *name, size_t name_len, const void *hash, size_t hash_size) {
/* Validate name is hex build id. */
for (unsigned int i = 0; i < name_len - 4; i++) {
if (isxdigit(name[i]) == 0) {
return false;
}
}
/* Read hash from name. */
uint8_t hash_from_name[0x20] = {0};
for (unsigned int name_ofs = 0, id_ofs = 0; name_ofs < name_len - 4; id_ofs++) {
hash_from_name[id_ofs] |= hex_nybble_to_u8(name[name_ofs++]) << 4;
hash_from_name[id_ofs] |= hex_nybble_to_u8(name[name_ofs++]);
}
return memcmp(hash, hash_from_name, hash_size) == 0;
}
static bool has_ips_patches(const char *dir, const void *hash, size_t hash_size) {
bool any_patches = false;
char path[0x301] = {0};
snprintf(path, sizeof(path) - 1, "%s", dir);
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 && !any_patches) {
if (strcmp(pdir_ent->d_name, ".") == 0 || strcmp(pdir_ent->d_name, "..") == 0) {
continue;
}
snprintf(path, sizeof(path) - 1, "%s/%s", dir, 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 && !any_patches) {
if (strcmp(ent->d_name, ".") == 0 || strcmp(ent->d_name, "..") == 0) {
continue;
}
size_t name_len = strlen(ent->d_name);
if ((4 < name_len && name_len <= 0x44) && ((name_len & 1) == 0) && strcmp(ent->d_name + name_len - 4, ".ips") == 0 && name_matches_hash(ent->d_name, name_len, hash, hash_size)) {
snprintf(path, sizeof(path) - 1, "%s/%s/%s", dir, pdir_ent->d_name, ent->d_name);
FILE *f_ips = fopen(path, "rb");
if (f_ips != NULL) {
uint8_t header[5];
if (fread(header, 5, 1, f_ips) == 1) {
if (memcmp(header, IPS_MAGIC, 5) == 0 || memcmp(header, IPS32_MAGIC, 5) == 0) {
any_patches = true;
}
}
fclose(f_ips);
}
}
}
closedir(patch_dir);
}
}
closedir(patches_dir);
}
return any_patches;
}
static void apply_ips_patches(const char *dir, void *mem, size_t mem_size, size_t prot_size, const void *hash, size_t hash_size) {
char path[0x301] = {0};
snprintf(path, sizeof(path) - 1, "%s", dir);
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 (strcmp(pdir_ent->d_name, ".") == 0 || strcmp(pdir_ent->d_name, "..") == 0) {
continue;
}
snprintf(path, sizeof(path) - 1, "%s/%s", dir, 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 (strcmp(ent->d_name, ".") == 0 || strcmp(ent->d_name, "..") == 0) {
continue;
}
size_t name_len = strlen(ent->d_name);
if ((4 < name_len && name_len <= 0x44) && ((name_len & 1) == 0) && strcmp(ent->d_name + name_len - 4, ".ips") == 0 && name_matches_hash(ent->d_name, name_len, hash, hash_size)) {
snprintf(path, sizeof(path) - 1, "%s/%s/%s", dir, pdir_ent->d_name, ent->d_name);
FILE *f_ips = fopen(path, "rb");
if (f_ips != NULL) {
uint8_t header[5];
if (fread(header, 5, 1, f_ips) == 1) {
if (memcmp(header, IPS_MAGIC, 5) == 0) {
apply_ips_patch(mem, mem_size, prot_size, false, f_ips);
} else if (memcmp(header, IPS32_MAGIC, 5) == 0) {
apply_ips_patch(mem, mem_size, prot_size, true, f_ips);
}
}
fclose(f_ips);
}
}
}
closedir(patch_dir);
}
}
closedir(patches_dir);
}
}
void apply_kernel_ips_patches(void *kernel, size_t kernel_size) {
uint8_t hash[0x20];
se_calculate_sha256(hash, kernel, kernel_size);
apply_ips_patches("atmosphere/kernel_patches", kernel, kernel_size, 0, hash, sizeof(hash));
}
static void kip1_blz_uncompress(void *hdr_end) {
uint8_t *u8_hdr_end = (uint8_t *)hdr_end;
uint32_t addl_size = ((u8_hdr_end[-4]) << 0) | ((u8_hdr_end[-3]) << 8) | ((u8_hdr_end[-2]) << 16) | ((u8_hdr_end[-1]) << 24);
uint32_t header_size = ((u8_hdr_end[-8]) << 0) | ((u8_hdr_end[-7]) << 8) | ((u8_hdr_end[-6]) << 16) | ((u8_hdr_end[-5]) << 24);
uint32_t cmp_and_hdr_size = ((u8_hdr_end[-12]) << 0) | ((u8_hdr_end[-11]) << 8) | ((u8_hdr_end[-10]) << 16) | ((u8_hdr_end[-9]) << 24);
unsigned char *cmp_start = (unsigned char *)(((uintptr_t)hdr_end) - cmp_and_hdr_size);
uint32_t cmp_ofs = cmp_and_hdr_size - header_size;
uint32_t out_ofs = cmp_and_hdr_size + addl_size;
while (out_ofs) {
unsigned char control = cmp_start[--cmp_ofs];
for (unsigned int i = 0; i < 8; i++) {
if (control & 0x80) {
if (cmp_ofs < 2) {
fatal_error("KIP1 decompression out of bounds!\n");
}
cmp_ofs -= 2;
uint16_t seg_val = ((unsigned int)cmp_start[cmp_ofs+1] << 8) | cmp_start[cmp_ofs];
uint32_t seg_size = ((seg_val >> 12) & 0xF) + 3;
uint32_t seg_ofs = (seg_val & 0x0FFF) + 3;
if (out_ofs < seg_size) {
/* Kernel restricts segment copy to stay in bounds. */
seg_size = out_ofs;
}
out_ofs -= seg_size;
for (unsigned int j = 0; j < seg_size; j++) {
cmp_start[out_ofs + j] = cmp_start[out_ofs + j + seg_ofs];
}
} else {
/* Copy directly. */
if (cmp_ofs < 1) {
fatal_error("KIP1 decompression out of bounds!\n");
}
cmp_start[--out_ofs] = cmp_start[--cmp_ofs];
}
control <<= 1;
if (out_ofs == 0) {
return;
}
}
}
}
static kip1_header_t *kip1_uncompress(kip1_header_t *kip, size_t *size) {
kip1_header_t new_header = *kip;
for (unsigned int i = 0; i < 3; i++) {
new_header.section_headers[i].compressed_size = new_header.section_headers[i].out_size;
}
new_header.flags &= 0xF8;
*size = kip1_get_size_from_header(&new_header);
unsigned char *new_kip = calloc(1, *size);
if (new_kip == NULL) {
return NULL;
}
*((kip1_header_t *)new_kip) = new_header;
size_t new_offset = 0x100;
size_t old_offset = 0x100;
for (unsigned int i = 0; i < 3; i++) {
memcpy(new_kip + new_offset, (unsigned char *)kip + old_offset, kip->section_headers[i].compressed_size);
if (kip->flags & (1 << i)) {
kip1_blz_uncompress(new_kip + new_offset + kip->section_headers[i].compressed_size);
}
new_offset += kip->section_headers[i].out_size;
old_offset += kip->section_headers[i].compressed_size;
}
return (kip1_header_t *)new_kip;
}
kip1_header_t *apply_kip_ips_patches(kip1_header_t *kip, size_t kip_size) {
uint8_t hash[0x20];
se_calculate_sha256(hash, kip, kip_size);
if (!has_ips_patches("atmosphere/kip_patches", hash, sizeof(hash))) {
return NULL;
}
print(SCREEN_LOG_LEVEL_MANDATORY, "[NXBOOT]: Patching KIP %08x%08x...\n", (uint32_t)(kip->title_id >> 32), (uint32_t)kip->title_id);
size_t uncompressed_kip_size;
kip1_header_t *uncompressed_kip = kip1_uncompress(kip, &uncompressed_kip_size);
if (uncompressed_kip == NULL) {
return NULL;
}
apply_ips_patches("atmosphere/kip_patches", uncompressed_kip, uncompressed_kip_size, 0x100, hash, sizeof(hash));
return uncompressed_kip;
}
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