ios-kernel-patch/deplaceholder.c
2010-12-31 19:58:55 +01:00

220 lines
8.5 KiB
C

#include <data/common.h>
#include <data/find.h>
#include <data/binary.h>
#include <data/cc.h>
#include <config/placeholder.h>
#include <data/running_kernel.h>
#include <data/dyld_cache_format.h>
// count the number of set bits
static int count_ones(uint32_t number) {
int result = 0;
for(; number; number >>= 1) {
result += (number & 1);
}
return result;
}
// ldmib<cond> r11/r11!, {.., .., .., sp, pc}
addr_t find_init_ldmib(struct binary *binary, uint32_t cond) {
range_t range;
for(int i = 0; (range = b_dyldcache_nth_segment(binary, i)).start; i++) {
uint32_t *p = rangeconv(range).start;
for(addr_t addr = range.start; addr + 4 <= (range.start + range.size); addr += 4) {
// <3 http://a.qoid.us/01x.py
// fun fact: on armv6 this is actually UNPREDICTABLE
uint32_t val = *p++;
if((val & 0xf9fe000) != 0x99ba000) continue;
uint32_t actual_cond = ((val & 0xf0000000) >> 28);
if(actual_cond != cond) continue;
uint32_t reglist = val & 0x1fff;
// The famous interview question: calculate the number of 1 bits
if(count_ones(reglist) != 3) continue;
return addr;
}
}
die("didn't find ldmib /anywhere/");
}
// ldmia<cond> r0/r0!, {.., .., sp,( lr,)? pc}
// OR
// ldmib<cond> r0/r0!, {.., sp,( lr,)? pc}
// aligned to 0x1000
// each set of two bits in valid_conds is:
// 0 - known false
// 1 - known true
// 2 - unknown
addr_t find_kernel_ldm(struct binary *binary, uint32_t valid_conds) {
range_t range;
uint32_t my_valid_conds = valid_conds;
for(int i = 0; (range = b_dyldcache_nth_segment(binary, i)).start; i++) {
if(!(binary->dyld_mappings[i].sfm_init_prot & PROT_EXEC)) continue;
char *p = rangeconv(range).start;
for(addr_t addr = range.start; addr + 4 <= (range.start + range.size); my_valid_conds = valid_conds, addr = (addr + 0x1000) & ~0xfff) {
back:;
uint32_t val = *((uint32_t *) (p + (addr - range.start)));
uint32_t cond = ((val & 0xf0000000) >> 28);
bool harmless = false;
if(cond != 15 && 0 == (my_valid_conds & (3 << (2*cond)))) {
harmless = true;
} else if(!(val & 0xc000000)) { // data processing
uint32_t rd = (val & 0xf000) >> 12;
if(rd != 0 && rd != 15) {
harmless = true;
if(!(val & (1 << 20))) my_valid_conds = 0x1aaaaaaa; // AL known 1, others unknown
} else if(rd == 0) {
uint32_t op = ((val & 0x1f00000) >> 20);
if(op == 17 || op == 19 || op == 21 || op == 23) {
harmless = true;
my_valid_conds = 0x1aaaaaaa;
}
}
}
if(harmless) {
//printf("@ %08x: %08x is harmless (vc=%08x)\n", addr, val, my_valid_conds);
addr += 4;
goto back;
}
if(cond == 15 || (1u << (2*cond)) != (my_valid_conds & (3 << (2*cond)))) {
continue;
}
//printf("ready to test %08x @ %08x\n", val, addr);
bool ldmib;
if((val & 0xf9fa000) == 0x890a000) {
ldmib = false;
} else if((val & 0xf9fa000) == 0x990a000) {
ldmib = true;
} else {
continue;
}
//printf("%08x -> %08x (%s)\n", addr, val, ldmib ? "ib" : "ia");
uint32_t reglist = val & 0x1fff;
if(count_ones(reglist) != (ldmib ? 1 : 2)) continue;
printf(":) %08x = %08x\n", addr, val);
return addr;
}
}
die("didn't find ldm /anywhere/");
}
void do_dyldcache(prange_t pr, struct binary *binary) {
bool is_armv7 = b_is_armv7(binary);
preplace32(pr, CONFIG_IS_ARMV7, (uint32_t) is_armv7);
int align = is_armv7 ? 2 : 4;
preplace32(pr, CONFIG_K4, b_dyldcache_find_anywhere(binary, is_armv7 ? "+ 00 68 b0 bd" : "- 00 00 90 e5 b0 80 bd e8", align));
preplace32(pr, CONFIG_K5, b_dyldcache_find_anywhere(binary, is_armv7 ? "+ 20 60 90 bd" : "- 00 00 84 e5 90 80 bd e8", align));
preplace32(pr, CONFIG_K6, b_dyldcache_find_anywhere(binary, is_armv7 ? "+ 20 44 90 bd" : "- 00 00 84 e0 90 80 bd e8", align));
preplace32(pr, CONFIG_K7, b_dyldcache_find_anywhere(binary, is_armv7 ? "+ 0f bd" : "- 0f 80 bd e8", align));
preplace32(pr, CONFIG_K9, b_dyldcache_find_anywhere(binary, "+ 0e bd", 2));
preplace32(pr, CONFIG_K10, b_dyldcache_find_anywhere(binary, is_armv7 ? "+ a7 f1 00 0d 80 bd" : "- 00 d0 47 e2 80 80 bd e8", align));
preplace32(pr, CONFIG_K11, b_dyldcache_find_anywhere(binary, "+ f0 bd", 2));
preplace32(pr, CONFIG_K12, b_dyldcache_find_anywhere(binary, is_armv7 ? "+ a0 47 b0 bd" : "- 34 ff 2f e1 b0 80 bd e8", align));
preplace32(pr, CONFIG_K14, b_dyldcache_find_anywhere(binary, "+ 20 58 90 bd", 2));
preplace32(pr, CONFIG_K15, b_dyldcache_find_anywhere(binary, is_armv7 ? "+ 40 f8 04 4b 90 bd" : "- 00 40 80 e5 90 80 bd e8", align));
preplace32(pr, CONFIG_K16, b_dyldcache_find_anywhere(binary, is_armv7 ? "+ 20 68 90 bd" : "- 00 00 94 e5 90 80 bd e8", align));
preplace32(pr, CONFIG_K17, b_dyldcache_find_anywhere(binary, is_armv7 ? "+ 25 60 b0 bd" : "- 00 50 84 e5 b0 80 bd e8", align));
preplace32(pr, CONFIG_K18, b_dyldcache_find_anywhere(binary, "+ 10 bd", 2));
preplace32(pr, CONFIG_K19, b_dyldcache_find_anywhere(binary, "+ 80 bd", 2));
preplace32(pr, CONFIG_KINIT, find_init_ldmib(binary, is_armv7 ? 4 /* MI */ : 5 /* PL */));
// NE, CS, MI, VC, HI, LT, LE, AL = 0b110100110010110
// >>> ''.join('0' + i for i in '110100110010110')
preplace32(pr, CONFIG_REMAP_FROM, find_kernel_ldm(binary, 0x14414114));
//b_dyldcache_load_macho(binary, "/usr/lib/libSystem.B.dylib");
//preplace32(pr, 0xfeed1001, b_sym(binary, "_sysctlbyname", true));
//preplace32(pr, 0xfeed1002, b_sym(binary, "_execve", true));
}
void do_dyld(prange_t pr, struct binary *binary) {
(void) pr; (void) binary;
}
void do_kernel(prange_t pr, struct binary *binary) {
addr_t sysent = find_data(b_macho_segrange(binary, "__DATA"), "21 00 00 00 00 10 86 00 -", 0, true);
preplace32(pr, CONFIG_SYSENT_PATCH, sysent + 4);
addr_t sysent_patch_orig = b_read32(binary, sysent + 4);
preplace32(pr, CONFIG_SYSENT_PATCH_ORIG, sysent_patch_orig);
preplace32(pr, CONFIG_TARGET_ADDR, (sysent_patch_orig & 0x00ffffff) | 0x2f000000);
}
int main(int argc, char **argv) {
struct binary kernel, dyld, cache;
b_init(&kernel);
b_init(&dyld);
b_init(&cache);
char **p = &argv[1];
if(!p[0]) goto usage;
while(p[0]) {
if(p[0][0] == '-') switch(p[0][1]) {
case 'C':
b_load_running_dyldcache(&cache, (void *) 0x30000000);
p++;
break;
case 'c':
if(!p[1]) goto usage;
b_load_dyldcache(&cache, p[1], false);
p += 2;
break;
case 'k':
if(!p[1]) goto usage;
b_load_macho(&kernel, p[1], false);
p += 2;
break;
case 'd':
if(!p[1]) goto usage;
b_load_macho(&dyld, p[1], false);
p += 2;
break;
case 'K': {
b_running_kernel_load_macho(&kernel);
p++;
break;
}
#ifdef IMG3_SUPPORT
case 'i': {
if(!p[1] || !p[2] || !p[3]) goto usage;
uint32_t key_bits;
prange_t key = parse_hex_string(p[2]);
prange_t iv = parse_hex_string(p[3]);
prange_t data = parse_img3_file(p[1], &key_bits);
prange_t kern = decrypt_and_decompress(key_bits, key, iv, data);
b_prange_load_macho(&kernel, kern, false);
p += 4;
break;
}
#endif
default:
goto usage;
}
else { // not a -
if(!p[1]) goto usage;
mode_t mode;
prange_t pr = load_file(p[0], true, &mode);
if(cache.valid) do_dyldcache(pr, &cache);
if(kernel.valid) do_kernel(pr, &kernel);
if(dyld.valid) do_dyld(pr, &dyld);
check_no_placeholders(pr);
store_file(pr, p[1], mode);
punmap(pr);
p += 2;
}
}
return 0;
usage:
fprintf(stderr, "Usage: data [-c cache | -C] [-d dyld] [-k kc | -K"
#ifdef IMG3_SUPPORT
" | -i kernel_img3 key iv"
#endif
"] infile outfile [infile outfile...]\n");
return 1;
}