/**
* Copyright (C) 2018 netsniffer
* mprop v1.0, 2017/01/19
* https://bbs.pediy.com/thread-215311.htm
*/
#include <unistd.h>
#include <ctype.h>
#include <stdio.h>
#include <errno.h>
#include <memory.h>
#include <string.h>
#include <sys/ptrace.h>
#include <sys/system_properties.h>
#define PROP_NAME_MAX 32
#define PROP_VALUE_MAX 92
static void dump_hex(const char* buf, int len)
{
const uint8_t *data = (const uint8_t*)buf;
int i;
char ascii_buf[17];
ascii_buf[16] = '\0';
for (i = 0; i < len; i++) {
int val = data[i];
int off = i % 16;
if (off == 0)
printf("%08x ", i);
printf("%02x ", val);
ascii_buf[off] = isprint(val) ? val : '.';
if (off == 15)
printf(" %-16s\n", ascii_buf);
}
i %= 16;
if (i) {
ascii_buf[i] = '\0';
while (i++ < 16)
printf(" ");
printf(" %-16s\n", ascii_buf);
}
}
#define ORI_INST 0x2e6f72
#define HACK_INST 0x2e6f73
int main(int argc, char **argv)
{
FILE *fp;
int m, rc;
int patch_count;
unsigned long maps, mape, addr, mlen;
unsigned long real_val, real_vaddr;
char perms[5];
char line[512];
char *buffer, *ro;
char* name = NULL, *value = NULL;
uint32_t tmp;
uint32_t dest_inst = ORI_INST;
uint32_t mod_inst = HACK_INST;
int restore = 0, verbose = 0;
for (m = 1; m < argc; m++) {
if (argv[m] == NULL)
continue;
if (argv[m][0] != '-') {
break;
}
if (argv[m][1] == 'r') {
restore = 1;
dest_inst = HACK_INST;
mod_inst = ORI_INST;
} else if (argv[m][1] == 'v') {
verbose = 1;
}
}
if (restore) {
fprintf(stderr, "restore ...\n");
}
else {
if (argc - m >= 2) {
// fprintf(stderr, "Usage: %s [-r] [-v] [prop_name] [prop_value]\n"
// "e.g.: %s ro.debuggable 1\n", argv[0], argv[0]);
name = argv[m];
value = argv[m+1];
}
fprintf(stderr, "start hacking ...\n");
}
fp = fopen("/proc/1/maps", "r");
if (!fp) {
perror("!! fopen ");
return 1;
}
// 00008000-000cb000 r-xp 00000000 00:01 6999 /init
memset(line, 0, sizeof(line));
while (fgets(line, sizeof(line), fp)) {
int main_exe = (strstr(line, "/init") != NULL) ? 1 : 0;
if (main_exe) {
rc = sscanf(line, "%lx-%lx %4s ", &maps, &mape, perms);
if (rc < 3) {
perror("!! sscanf ");
return 1;
}
if (perms[0] == 'r' && perms[1] == '-' && perms[2] == 'x' && perms[3] == 'p') {
break;
}
}
}
fclose(fp);
fprintf(stderr, "target mapped area: 0x%lx-0x%lx\n", maps, mape);
mlen = mape - maps;
buffer = (char *) calloc(1, mlen + 16);
if (!buffer) {
perror("!! malloc ");
return 1;
}
rc = ptrace(PTRACE_ATTACH, 1, 0, 0);
if (rc < 0) {
perror("!! ptrace ");
return rc;
}
for (addr = maps; addr < mape; addr += 4) {
tmp = ptrace(PTRACE_PEEKTEXT, 1, (void *) addr, 0);
*((uint32_t*)(buffer + addr - maps)) = tmp;
}
if (verbose) {
dump_hex(buffer, mlen);
}
for (m = 0; m < mlen; ++m) {
if (dest_inst == *(uint32_t*)(buffer+m)) { // 72 6F 2E 00 == ro.\0
break;
}
}
if (m >= mlen) {
fprintf(stderr, ">> inject position not found, may be already patched!\n");
}
else {
real_vaddr = maps + m;
real_val = *(uint32_t*)(buffer+m);
fprintf(stderr, ">> patching at: 0x%lx [0x%lx -> 0x%08x]\n", real_vaddr, real_val, mod_inst);
tmp = mod_inst;
rc = ptrace(PTRACE_POKETEXT, 1, (void *)real_vaddr, (void*)tmp);
if (rc < 0) {
perror("!! patching failed ");
}
tmp = ptrace(PTRACE_PEEKTEXT, 1, (void *)real_vaddr, 0);
fprintf(stderr, ">> %s reread: [0x%lx] => 0x%08x\n", restore ? "restored!" : "patched!", real_vaddr, tmp);
}
free(buffer);
rc = ptrace(PTRACE_DETACH, 1, 0, 0);
if (!restore && (name && value && name[0] != 0)) {
char propbuf[PROP_VALUE_MAX];
fprintf(stderr, "-- setprop: [%s] = [%s]\n", name, value);
__system_property_set(name, value);
usleep(400000);
__system_property_get(name, propbuf);
fprintf(stderr, "++ getprop: [%s] = [%s]\n", name, propbuf);
}
return rc;
}
