Android so的注入流程如下：
demo分为三部分：
一个是普通linux进程或Android进程，在Linux或者ndk编译成可执行文件，这里就写一个非常简单的每隔着一秒打印一行log的程序；
#include<stdio.h>
int main()
{
static i =0;
while(1){
sleep(1);
printf("i am target program %d\n",i);
i++;
}
return 0;
}
第二个要注入的模块，编译成so文件，里面包含要注入的函数；
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <android/log.h>
#include <elf.h>
#include <fcntl.h>
#define LOG_TAG "DEBUG"
#define LOGD(fmt, args...) __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, fmt, ##args)
int hook_entry(char * a){
LOGD("Hook success, pid = %d\n", getpid());
LOGD("Hello %s\n", a);
return 0;
}
第三个是我们的ptrace注入模块，编译成elf可执行文件；
主要流程如下：
- attach到远程进程
- 保存寄存器环境，也叫保护现场，就是通过
ptrace的PTRACE_GETREGS参数获取目标进程当前寄存器的情况，然后复制出来；- 获取目标程序的
mmap,dlopen,dlsym,dlclose地址，首先分别获取目标进程和本地进程中libc.so的基址，然后获取本地进程中上述函数的地址，通过本地函数地址-本地libc.so基址+目标进程libc.so基址=目标进程中函数地址；- 远程调用
mmap函数申请内存空间用来保存参数信息，这里需要通过ptrace函数的PTRACE_POKETEXT、PTRACE_PEEKTEXT参数手动填些mmap函数的参数到寄存器中（大于四个需要手动写入sp堆栈寄存器），然后通过PTRACE_SETREGS参数设置寄存器，通过PTRACE_CONT参数使子进程继续执行完mmap函数后发出信号，然后再次保存现场；- 然后获取
mmap函数返回地址，将要注入的so写入该地址；- 远程调用
dlopen函数打开写入的so，过程和第四步相同；- 远程调用
dlsym函数加载目标函数地址，返回目标函数地址；- 写入目标函数参数，远程调用目标函数，执行；
- 远程调用
dlclose函数卸载so文件；- 恢复现场，即恢复寄存器原始环境；
- 远程调用
detach使进程继续；
#include <stdio.h>
#include <stdlib.h>
//#include <asm/user.h>
#include <asm/ptrace.h>
#include <sys/ptrace.h>
#include <sys/wait.h>
#include <sys/mman.h>
#include <dlfcn.h>
#include <dirent.h>
#include <unistd.h>
#include <string.h>
#include <elf.h>
#include <android/log.h>
#if defined(__i386__)
#define pt_regs user_regs_struct
#endif
#define ENABLE_DEBUG 1
#if ENABLE_DEBUG
#define LOG_TAG "INJECT"
#define LOGD(fmt, args...) __android_log_print(ANDROID_LOG_DEBUG,LOG_TAG, fmt, ##args)
#define DEBUG_PRINT(format,args...) \
LOGD(format, ##args)
#else
#define DEBUG_PRINT(format,args...)
#endif
#define CPSR_T_MASK ( 1u << 5 )
const char *libc_path = "/system/lib/libc.so";
const char *linker_path = "/system/bin/linker";
int ptrace_readdata(pid_t pid, uint8_t *src, uint8_t *buf, size_t size)
{
uint32_t i, j, remain;
uint8_t *laddr;
union u {
long val;
char chars[sizeof(long)];
} d;
j = size / 4;
remain = size % 4;
laddr = buf;
for (i = 0; i < j; i ++) {
d.val = ptrace(PTRACE_PEEKTEXT, pid, src, 0);
memcpy(laddr, d.chars, 4);
src += 4;
laddr += 4;
}
if (remain > 0) {
d.val = ptrace(PTRACE_PEEKTEXT, pid, src, 0);
memcpy(laddr, d.chars, remain);
}
return 0;
}
int ptrace_writedata(pid_t pid, uint8_t *dest, uint8_t *data, size_t size)
{
uint32_t i, j, remain;
uint8_t *laddr;
union u {
long val;
char chars[sizeof(long)];
} d;
j = size / 4;
remain = size % 4;
laddr = data;
for (i = 0; i < j; i ++) {
memcpy(d.chars, laddr, 4);
ptrace(PTRACE_POKETEXT, pid, dest, d.val);
dest += 4;
laddr += 4;
}
if (remain > 0) {
d.val = ptrace(PTRACE_PEEKTEXT, pid, dest, 0);
for (i = 0; i < remain; i ++) {
d.chars[i] = *laddr ++;
}
ptrace(PTRACE_POKETEXT, pid, dest, d.val);
}
return 0;
}
#if defined(__arm__)
int ptrace_call(pid_t pid, uint32_t addr, long *params, uint32_t num_params, struct pt_regs* regs)
{
uint32_t i;
for (i = 0; i < num_params && i < 4; i ++) {
regs->uregs[i] = params[i];
}
//
// push remained params onto stack
//
if (i < num_params) {
regs->ARM_sp -= (num_params - i) * sizeof(long) ;
ptrace_writedata(pid, (void *)regs->ARM_sp, (uint8_t *)¶ms[i], (num_params - i) * sizeof(long));
}
regs->ARM_pc = addr;
if (regs->ARM_pc & 1) {
/* thumb */
regs->ARM_pc &= (~1u);
regs->ARM_cpsr |= CPSR_T_MASK;
} else {
/* arm */
regs->ARM_cpsr &= ~CPSR_T_MASK;
}
regs->ARM_lr = 0;
if (ptrace_setregs(pid, regs) == -1
|| ptrace_continue(pid) == -1) {
printf("error\n");
return -1;
}
int stat = 0;
waitpid(pid, &stat, WUNTRACED);
while (stat != 0xb7f) {
if (ptrace_continue(pid) == -1) {
printf("error\n");
return -1;
}
waitpid(pid, &stat, WUNTRACED);
}
return 0;
}
#elif defined(__i386__)
long ptrace_call(pid_t pid, uint32_t addr, long *params, uint32_t num_params, struct user_regs_struct * regs)
{
regs->esp -= (num_params) * sizeof(long) ;
ptrace_writedata(pid, (void *)regs->esp, (uint8_t *)params, (num_params) * sizeof(long));
long tmp_addr = 0x00;
regs->esp -= sizeof(long);
ptrace_writedata(pid, regs->esp, (char *)&tmp_addr, sizeof(tmp_addr));
regs->eip = addr;
if (ptrace_setregs(pid, regs) == -1
|| ptrace_continue( pid) == -1) {
printf("error\n");
return -1;
}
int stat = 0;
waitpid(pid, &stat, WUNTRACED);
while (stat != 0xb7f) {
if (ptrace_continue(pid) == -1) {
printf("error\n");
return -1;
}
waitpid(pid, &stat, WUNTRACED);
}
return 0;
}
#else
#error "Not supported"
#endif
int ptrace_getregs(pid_t pid, struct pt_regs * regs)
{
if (ptrace(PTRACE_GETREGS, pid, NULL, regs) < 0) {
perror("ptrace_getregs: Can not get register values");
return -1;
}
return 0;
}
int ptrace_setregs(pid_t pid, struct pt_regs * regs)
{
if (ptrace(PTRACE_SETREGS, pid, NULL, regs) < 0) {
perror("ptrace_setregs: Can not set register values");
return -1;
}
return 0;
}
int ptrace_continue(pid_t pid)
{
if (ptrace(PTRACE_CONT, pid, NULL, 0) < 0) {
perror("ptrace_cont");
return -1;
}
return 0;
}
int ptrace_attach(pid_t pid)
{
if (ptrace(PTRACE_ATTACH, pid, NULL, 0) < 0) {
perror("ptrace_attach");
return -1;
}
int status = 0;
waitpid(pid, &status , WUNTRACED);
return 0;
}
int ptrace_detach(pid_t pid)
{
if (ptrace(PTRACE_DETACH, pid, NULL, 0) < 0) {
perror("ptrace_detach");
return -1;
}
return 0;
}
void* get_module_base(pid_t pid, const char* module_name)
{
FILE *fp;
long addr = 0;
char *pch;
char filename[32];
char line[1024];
if (pid < 0) {
/* self process */
snprintf(filename, sizeof(filename), "/proc/self/maps", pid);
} else {
snprintf(filename, sizeof(filename), "/proc/%d/maps", pid);
}
fp = fopen(filename, "r");
if (fp != NULL) {
while (fgets(line, sizeof(line), fp)) {
if (strstr(line, module_name)) {
pch = strtok( line, "-" );
addr = strtoul( pch, NULL, 16 );
if (addr == 0x8000)
addr = 0;
break;
}
}
fclose(fp) ;
}
return (void *)addr;
}
void* get_remote_addr(pid_t target_pid, const char* module_name, void* local_addr)
{
void* local_handle, *remote_handle;
local_handle = get_module_base(-1, module_name);
remote_handle = get_module_base(target_pid, module_name);
DEBUG_PRINT("[+] get_remote_addr: local[%x], remote[%x]\n", local_handle, remote_handle);
void * ret_addr = (void *)((uint32_t)local_addr + (uint32_t)remote_handle - (uint32_t)local_handle);
#if defined(__i386__)
if (!strcmp(module_name, libc_path)) {
ret_addr += 2;
}
#endif
return ret_addr;
}
int find_pid_of(const char *process_name)
{
int id;
pid_t pid = -1;
DIR* dir;
FILE *fp;
char filename[32];
char cmdline[256];
struct dirent * entry;
if (process_name == NULL)
return -1;
dir = opendir("/proc");
if (dir == NULL)
return -1;
while((entry = readdir(dir)) != NULL) {
id = atoi(entry->d_name);
if (id != 0) {
sprintf(filename, "/proc/%d/cmdline", id);
fp = fopen(filename, "r");
if (fp) {
fgets(cmdline, sizeof(cmdline), fp);
fclose(fp);
if (strcmp(process_name, cmdline) == 0) {
/* process found */
pid = id;
break;
}
}
}
}
closedir(dir);
return pid;
}
long ptrace_retval(struct pt_regs * regs)
{
#if defined(__arm__)
return regs->ARM_r0;
#elif defined(__i386__)
return regs->eax;
#else
#error "Not supported"
#endif
}
long ptrace_ip(struct pt_regs * regs)
{
#if defined(__arm__)
return regs->ARM_pc;
#elif defined(__i386__)
return regs->eip;
#else
#error "Not supported"
#endif
}
int ptrace_call_wrapper(pid_t target_pid, const char * func_name, void * func_addr, long * parameters, int param_num, struct pt_regs * regs)
{
DEBUG_PRINT("[+] Calling %s in target process.\n", func_name);
if (ptrace_call(target_pid, (uint32_t)func_addr, parameters, param_num, regs) == -1)
return -1;
if (ptrace_getregs(target_pid, regs) == -1)
return -1;
DEBUG_PRINT("[+] Target process returned from %s, return value=%x, pc=%x \n",
func_name, ptrace_retval(regs), ptrace_ip(regs));
return 0;
}
int inject_remote_process(pid_t target_pid, const char *library_path, const char *function_name, const char *param, size_t param_size)
{
int ret = -1;
void *mmap_addr, *dlopen_addr, *dlsym_addr, *dlclose_addr, *dlerror_addr;
void *local_handle, *remote_handle, *dlhandle;
uint8_t *map_base = 0;
uint8_t *dlopen_param1_ptr, *dlsym_param2_ptr, *saved_r0_pc_ptr, *inject_param_ptr, *remote_code_ptr, *local_code_ptr;
struct pt_regs regs, original_regs;
extern uint32_t _dlopen_addr_s, _dlopen_param1_s, _dlopen_param2_s, _dlsym_addr_s, \
_dlsym_param2_s, _dlclose_addr_s, _inject_start_s, _inject_end_s, _inject_function_param_s, \
_saved_cpsr_s, _saved_r0_pc_s;
uint32_t code_length;
long parameters[10];
DEBUG_PRINT("[+] Injecting process: %d\n", target_pid);
if (ptrace_attach(target_pid) == -1)
goto exit;
if (ptrace_getregs(target_pid, ®s) == -1)
goto exit;
/* save original registers */
memcpy(&original_regs, ®s, sizeof(regs));
mmap_addr = get_remote_addr(target_pid, libc_path, (void *)mmap);
DEBUG_PRINT("[+] Remote mmap address: %x\n", mmap_addr);
/* call mmap */
parameters[0] = 0; // addr
parameters[1] = 0x4000; // size
parameters[2] = PROT_READ | PROT_WRITE | PROT_EXEC; // prot
parameters[3] = MAP_ANONYMOUS | MAP_PRIVATE; // flags
parameters[4] = 0; //fd
parameters[5] = 0; //offset
if (ptrace_call_wrapper(target_pid, "mmap", mmap_addr, parameters, 6, ®s) == -1)
goto exit;
map_base = ptrace_retval(®s);
dlopen_addr = get_remote_addr( target_pid, linker_path, (void *)dlopen );
dlsym_addr = get_remote_addr( target_pid, linker_path, (void *)dlsym );
dlclose_addr = get_remote_addr( target_pid, linker_path, (void *)dlclose );
dlerror_addr = get_remote_addr( target_pid, linker_path, (void *)dlerror );
DEBUG_PRINT("[+] Get imports: dlopen: %x, dlsym: %x, dlclose: %x, dlerror: %x\n",
dlopen_addr, dlsym_addr, dlclose_addr, dlerror_addr);
printf("library path = %s\n", library_path);
ptrace_writedata(target_pid, map_base, library_path, strlen(library_path) + 1);
parameters[0] = map_base;
parameters[1] = RTLD_NOW| RTLD_GLOBAL;
if (ptrace_call_wrapper(target_pid, "dlopen", dlopen_addr, parameters, 2, ®s) == -1)
goto exit;
void * sohandle = ptrace_retval(®s);
#define FUNCTION_NAME_ADDR_OFFSET 0x100
ptrace_writedata(target_pid, map_base + FUNCTION_NAME_ADDR_OFFSET, function_name, strlen(function_name) + 1);
parameters[0] = sohandle;
parameters[1] = map_base + FUNCTION_NAME_ADDR_OFFSET;
if (ptrace_call_wrapper(target_pid, "dlsym", dlsym_addr, parameters, 2, ®s) == -1)
goto exit;
void * hook_entry_addr = ptrace_retval(®s);
DEBUG_PRINT("hook_entry_addr = %p\n", hook_entry_addr);
#define FUNCTION_PARAM_ADDR_OFFSET 0x200
ptrace_writedata(target_pid, map_base + FUNCTION_PARAM_ADDR_OFFSET, param, strlen(param) + 1);
parameters[0] = map_base + FUNCTION_PARAM_ADDR_OFFSET;
if (ptrace_call_wrapper(target_pid, "hook_entry", hook_entry_addr, parameters, 1, ®s) == -1)
goto exit;
printf("Press enter to dlclose and detach\n");
getchar();
parameters[0] = sohandle;
if (ptrace_call_wrapper(target_pid, "dlclose", dlclose, parameters, 1, ®s) == -1)
goto exit;
/* restore */
ptrace_setregs(target_pid, &original_regs);
ptrace_detach(target_pid);
ret = 0;
exit:
return ret;
}
int main(int argc, char** argv) {
pid_t target_pid;
target_pid = find_pid_of(argv[1]);
printf("target_pid:%d\n",target_pid );
if (-1 == target_pid) {
printf("Can't find the process\n");
return -1;
}
inject_remote_process(target_pid, argv[2], "hook_entry", "I'm parameter!", strlen("I'm parameter!"));
return 0;
}
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