#include <stdio.h> #include <stdlib.h> #include <sys/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> #include <sys/uio.h> #if defined(__i386__) #define pt_regs user_regs_struct #elif defined(__aarch64__) #define pt_regs user_pt_regs #define uregs regs #define ARM_pc pc #define ARM_sp sp #define ARM_cpsr pstate #define ARM_lr regs[30] #define ARM_r0 regs[0] #define PTRACE_GETREGS PTRACE_GETREGSET #define PTRACE_SETREGS PTRACE_SETREGSET #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 ) #if defined(__aarch64__) const char *libc_path = "/system/lib64/libc.so"; const char *linker_path = "/system/bin/linker64"; #else const char *libc_path = "/system/lib/libc.so"; const char *linker_path = "/system/bin/linker"; #endif int ptrace_readdata(pid_t pid, uint8_t *src, uint8_t *buf, size_t size) { long i, j, remain; uint8_t *laddr; size_t bytes_width = sizeof(long); union u { long val; char chars[bytes_width]; } d; j = size / bytes_width; remain = size % bytes_width; laddr = buf; for (i = 0; i < j; i ++) { d.val = ptrace(PTRACE_PEEKTEXT, pid, src, 0); memcpy(laddr, d.chars, bytes_width); src += bytes_width; laddr += bytes_width; } if (remain > 0) { d.val = ptrace(PTRACE_PEEKTEXT, pid, src, 0); memcpy(laddr, d.chars, remain); } return 0; } /* Func : 將size字節的data數據寫入到pid進程的dest地址處 @param dest: 目的進程的棧地址 @param data: 需要寫入的數據的起始地址 @param size: 需要寫入的數據的大小，以字節為單位 */ int ptrace_writedata(pid_t pid, uint8_t *dest, uint8_t *data, size_t size) { long i, j, remain; uint8_t *laddr; size_t bytes_width = sizeof(long); //很奇妙的聯合體，這樣就能夠方便的以字節為單位寫入4字節數據，再以long為單位ptrace_poketext到棧中  union u { long val; char chars[bytes_width]; } d; j = size / bytes_width; remain = size % bytes_width; laddr = data; //先以4字節為單位進行數據寫入 for (i = 0; i < j; i ++) { memcpy(d.chars, laddr, bytes_width); ptrace(PTRACE_POKETEXT, pid, dest, d.val); dest += bytes_width; laddr += bytes_width; } if (remain > 0) { //為了最大程度的保持原棧的數據，先讀取dest的long數據，然后只更改其中的前remain字節，再寫回 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; } /* 功能總結： 1，將要履行的指令寫入寄存器中，指令長度大于4個long的話，需要將剩余的指令通過ptrace_writedata函數寫入棧中； 2，使用ptrace_continue函數運行目的進程，直到目的進程返回狀態值0xb7f（對該值的分析見后面紅字）； 3，函數履行完以后，目標進程掛起，使用ptrace_getregs函數獲得當前的所有寄存器值，方便后面使用ptrace_retval函數獲得函數的返回值。 */ #if defined(__arm__) || defined(__aarch64__) int ptrace_call(pid_t pid, uintptr_t addr, long *params, int num_params, struct pt_regs* regs) { int i; #if defined(__arm__) int num_param_registers = 4; #elif defined(__aarch64__) int num_param_registers = 8; #endif for (i = 0; i < num_params && i < num_param_registers; 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 *)& params[i], (num_params - i) * sizeof(long)); } //將PC寄存器值設為目標函數的地址 regs->ARM_pc = addr; //進行指令集判斷  if (regs->ARM_pc & 1) { /* thumb */ regs->ARM_pc &= (~1u); // #define CPSR_T_MASK  ( 1u << 5 )  CPSR為程序狀態寄存器 regs->ARM_cpsr |= CPSR_T_MASK; } else { /* arm */ regs->ARM_cpsr &= ~CPSR_T_MASK; } //設置子程序的返回地址為空，以便函數履行完后，返回到null地址，產生SIGSEGV毛病，詳細作用見后面的紅字分析 regs->ARM_lr = 0; /*     *Ptrace_setregs就是將修改后的regs寫入寄存器中，然后調用ptrace_continue來履行我們指定的代碼     */ if (ptrace_setregs(pid, regs) == ⑴ || ptrace_continue(pid) == ⑴) { printf("error\n"); return ⑴; } int stat = 0; waitpid(pid, &stat, WUNTRACED); /* WUNTRACED告知waitpid，如果子進程進入暫停狀態，那末就立即返回。如果是被ptrace的子進程，那末即便不提供WUNTRACED參數，也會在子進程進入暫停狀態的時候立即返回。 對使用ptrace_cont運行的子進程，它會在3種情況下進入暫停狀態：①下1次系統調用；②子進程退出；③子進程的履行產生毛病。這里的0xb7f就表示子進程進入了暫停狀態，且發送的毛病信號為11(SIGSEGV)，它表示試圖訪問未分配給自己的內存, 或試圖往沒有寫權限的內存地址寫數據。那末甚么時候會產生這類毛病呢？明顯，當子進程履行完注入的函數后，由于我們在前面設置了regs->ARM_lr = 0，它就會返回到0地址處繼續履行，這樣就會產生SIGSEGV了！*/ //這個循環是不是必須我還不肯定。由于目前每次ptrace_call調用一定會返回0xb7f，不過在這也算是增加容錯性吧~ //通過看ndk的源碼sys/wait.h和man waitpid可以知道這個0xb7f的具體作用。首先說1下stat的值：高2字節用于表示致使子進程的退出或暫停狀態信號值，低2字節表示子進程是退出(0x0)還是暫停(0x7f)狀態。0xb7f就表示子進程為暫停狀態，致使它暫停的信號量為11即sigsegv毛病。 while (stat != 0xb7f) { if (ptrace_continue(pid) == ⑴) { printf("error\n"); return ⑴; } waitpid(pid, &stat, WUNTRACED); } return 0; } #elif defined(__i386__) long ptrace_call(pid_t pid, uintptr_t addr, long *params, int 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) == ⑴ || ptrace_continue( pid) == ⑴) { printf("error\n"); return ⑴; } int stat = 0; waitpid(pid, &stat, WUNTRACED); while (stat != 0xb7f) { if (ptrace_continue(pid) == ⑴) { printf("error\n"); return ⑴; } waitpid(pid, &stat, WUNTRACED); } return 0; } #else #error "Not supported" #endif int ptrace_getregs(pid_t pid, struct pt_regs * regs) { #if defined (__aarch64__) int regset = NT_PRSTATUS; struct iovec ioVec; ioVec.iov_base = regs; ioVec.iov_len = sizeof(*regs); if (ptrace(PTRACE_GETREGSET, pid, (void*)regset, &ioVec) < 0) { perror("ptrace_getregs: Can not get register values"); printf(" io %llx, %d", ioVec.iov_base, ioVec.iov_len); return ⑴; } return 0; #else if (ptrace(PTRACE_GETREGS, pid, NULL, regs) < 0) { perror("ptrace_getregs: Can not get register values"); return ⑴; } return 0; #endif } int ptrace_setregs(pid_t pid, struct pt_regs * regs) { #if defined (__aarch64__) int regset = NT_PRSTATUS; struct iovec ioVec; ioVec.iov_base = regs; ioVec.iov_len = sizeof(*regs); if (ptrace(PTRACE_SETREGSET, pid, (void*)regset, &ioVec) < 0) { perror("ptrace_setregs: Can not get register values"); return ⑴; } return 0; #else if (ptrace(PTRACE_SETREGS, pid, NULL, regs) < 0) { perror("ptrace_setregs: Can not set register values"); return ⑴; } return 0; #endif } int ptrace_continue(pid_t pid) { if (ptrace(PTRACE_CONT, pid, NULL, 0) < 0) { perror("ptrace_cont"); return ⑴; } return 0; } int ptrace_attach(pid_t pid) { if (ptrace(PTRACE_ATTACH, pid, NULL, 0) < 0) { perror("ptrace_attach"); return ⑴; } 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 ⑴; } return 0; } //明顯，這里面核心的就是get_module_base函數： /* 此函數的功能就是通過遍歷/proc/pid/maps文件，來找到目的module_name的內存映照起始地址。 由于內存地址的表達方式是startAddrxxxxxxx-endAddrxxxxxxx的，所以會在后面使用strtok(line,"-")來分割字符串 如果pid = ⑴,表示獲得本地進程的某個模塊的地址， 否則就是pid進程的某個模塊的地址。 */ 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)) { //分解字符串為1組字符串。line為要分解的字符串，"-"為分隔符字符串。 pch = strtok( line, "-" ); //將參數pch字符串根據參數base(表示進制)來轉換成無符號的長整型數  addr = strtoull( pch, NULL, 16 ); if (addr == 0x8000) addr = 0; break; } } fclose(fp) ; } return (void *)addr; } /* 該函數為1個封裝函數，通過調用get_module_base函數來獲得目的進程的某個模塊的起始地址，然后通過公式計算出指定函數在目的進程的起始地址。 */ void* get_remote_addr(pid_t target_pid, const char* module_name, void* local_addr) { void* local_handle, *remote_handle; //獲得本地某個模塊的起始地址 local_handle = get_module_base(⑴, module_name); //獲得遠程pid的某個模塊的起始地址 remote_handle = get_module_base(target_pid, module_name); DEBUG_PRINT("[+] get_remote_addr: local[%llx], remote[%llx]\n", local_handle, remote_handle); /*這需要我們好好理解：local_addr - local_handle的值為指定函數(如mmap)在該模塊中的偏移量，然后再加上rempte_handle，結果就為指定函數在目的進程的虛擬地址*/ void * ret_addr = (void *)((uintptr_t)local_addr + (uintptr_t)remote_handle - (uintptr_t)local_handle); #if defined(__i386__) if (!strcmp(module_name, libc_path)) { ret_addr += 2; } #endif return ret_addr; } //根據name找到pid int find_pid_of(const char *process_name) { int id; pid_t pid = ⑴; DIR* dir; FILE *fp; char filename[32]; char cmdline[256]; struct dirent * entry; if (process_name == NULL) return ⑴; dir = opendir("/proc"); if (dir == NULL) return ⑴; 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; } uint64_t ptrace_retval(struct pt_regs * regs) { #if defined(__arm__) || defined(__aarch64__) return regs->ARM_r0; #elif defined(__i386__) return regs->eax; #else #error "Not supported" #endif } uint64_t ptrace_ip(struct pt_regs * regs) { #if defined(__arm__) || defined(__aarch64__) return regs->ARM_pc; #elif defined(__i386__) return regs->eip; #else #error "Not supported" #endif } //總結1下ptrace_call_wrapper，它的完成兩個功能： //1是調用ptrace_call函數來履行指定函數，履行完后將子進程掛起； //2是調用ptrace_getregs函數獲得所有寄存器的值，主要是為了獲得r0即函數的返回值。 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, (uintptr_t)func_addr, parameters, param_num, regs) == ⑴) return ⑴; if (ptrace_getregs(target_pid, regs) == ⑴) return ⑴; DEBUG_PRINT("[+] Target process returned from %s, return value=%llx, pc=%llx \n", func_name, ptrace_retval(regs), ptrace_ip(regs)); return 0; } //遠程注入 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 = ⑴; 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; long parameters[10]; DEBUG_PRINT("[+] Injecting process: %d\n", target_pid); //①ATTATCH，指定目標進程，開始調試 if (ptrace_attach(target_pid) == ⑴) goto exit; //②GETREGS，獲得目標進程的寄存器，保存現場 if (ptrace_getregs(target_pid, &regs) == ⑴) goto exit; /* save original registers */ memcpy(&original_regs, &regs, sizeof(regs)); //③通過get_remote_addr函數獲得目的進程的mmap函數的地址，以便為libxxx.so分配內存 /* 需要對(void*)mmap進行說明：這是獲得inject本身進程的mmap函數的地址，由于mmap函數在libc.so  庫中，為了將libxxx.so加載到目的進程中，就需要使用目的進程的mmap函數，所以需要查找到libc.so庫在目的進程的起始地址。 */ mmap_addr = get_remote_addr(target_pid, libc_path, (void *)mmap); DEBUG_PRINT("[+] Remote mmap address: %llx\n", mmap_addr); /* call mmap (null, 0x4000, PROT_READ | PROT_WRITE | PROT_EXEC,                          MAP_ANONYMOUS | MAP_PRIVATE, 0, 0); 匿名申請1塊0x4000大小的內存 */ 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, &regs) == ⑴) goto exit; //⑤從寄存器中獲得mmap函數的返回值，即申請的內存首地址： map_base = ptrace_retval(&regs); //⑥順次獲得linker中dlopen、dlsym、dlclose、dlerror函數的地址: 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: %llx, dlsym: %llx, dlclose: %llx, dlerror: %llx\n", dlopen_addr, dlsym_addr, dlclose_addr, dlerror_addr); printf("library path = %s\n", library_path); //⑦調用dlopen函數： /* ①將要注入的so名寫入前面mmap出來的內存 ②寫入dlopen代碼 ③履行dlopen("libxxx.so", RTLD_NOW ! RTLD_GLOBAL) RTLD_NOW之類的參數作用可參考： http://baike.baidu.com/view/2907309.htm?fr=aladdin ④獲得dlopen的返回值，寄存在sohandle變量中 */ 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, &regs) == ⑴) goto exit; void * sohandle = ptrace_retval(&regs); if(!sohandle) { if (ptrace_call_wrapper(target_pid, "dlerror", dlerror_addr, 0, 0, &regs) == ⑴) goto exit; uint8_t *errret = ptrace_retval(&regs); uint8_t errbuf[100]; ptrace_readdata(target_pid, errret, errbuf, 100); } //⑧調用dlsym函數 /* 同等于hook_entry_addr = (void *)dlsym(sohandle, "hook_entry"); */ #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, &regs) == ⑴) goto exit; void * hook_entry_addr = ptrace_retval(&regs); DEBUG_PRINT("hook_entry_addr = %p\n", hook_entry_addr); //⑨調用hook_entry函數： #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, &regs) == ⑴) goto exit; printf("Press enter to dlclose and detach\n"); getchar(); parameters[0] = sohandle; //⑩調用dlclose關閉lib: if (ptrace_call_wrapper(target_pid, "dlclose", dlclose, parameters, 1, &regs) == ⑴) goto exit; /* restore */ //?恢復現場并退出ptrace: 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("system_server"); if (⑴ == target_pid) { printf("Can't find the process\n"); return ⑴; } //target_pid = find_pid_of("/data/test"); inject_remote_process(target_pid, "/data/libhello.so", "hook_entry", "I'm parameter!", strlen("I'm parameter!")); return 0; }

APP_ABI :=arm64-v8a armeabi-v7a

LOCAL_PATH := $(call my-dir) include $(CLEAR_VARS) LOCAL_MODULE := inject LOCAL_SRC_FILES := inject.c #shellcode.s LOCAL_LDLIBS += -L$(SYSROOT)/usr/lib -llog #LOCAL_FORCE_STATIC_EXECUTABLE := true include $(BUILD_EXECUTABLE)

#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; }