android hook 框架 libinject2 简介、编译、运行

简介:

libinject 最开始是2011年看雪android安全版版主之一‘古河’大神发布的一份android平台的注入库:  发个Android平台上的注入代码  ,网上很多随后发布的注入代码都是其变种,不过我这几天尝试运行那份代码,发现有些问题,本博运行和分析的代码是另外一位大神的改进版本,在我的环境里运行注入和挂钩都成功了 : Android中的so注入(inject)和挂钩(hook) - For both x86 and arm ,为了表示区别,我把这个项目称为  libinject2 。 

 

编译运行:

1. 在android studio里新建一个module(其实也可以随便把代码放在某个目录下,直接用ndk-build编译的,我这里放在android studio里主要为了方便编辑代码),目录如下

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非常简单,就2个文件,一个inject.c存放源码,jni目录下 Android.mk 存放编译脚本,原文作者同时支持了i386和arm,我在测试的时候,把i386的代码去掉了(将原链接的inject.c代码拷贝下面,把 i386 宏包围的代码都去掉,并且去掉了 Application.mk 文件)

2. Android.mk 内容如下

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

对于Android.mk文件的格式,可以参考 这里

3. 在 win7 下下载一个ndk包,设置目录到PATH环境变量,cmd进入终端,cd进入上述jni目录,执行 ndk-build , 正常情况下,会在 libs/armeabi/ 下生成 inject 可执行程序

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4. 在android studio 里再新建一个module,用于编译测试用的动态库

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其中,hello.c 内容如下:

#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;
}

提供了一个入口函数hook_entry,里边调用android的日志函数,最后的日志会在  logcat 里出现,通过  adb logcat 命令可以查看

Android.mk 内容如下

LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_LDLIBS += -L$(SYSROOT)/usr/lib -llog   #增加了对android log 库的链接
LOCAL_MODULE    := hello
LOCAL_SRC_FILES := ../hello.c
include $(BUILD_SHARED_LIBRARY) #指定编译为动态库

同样,使用 ndk-build 编译后,libs/armeabi/ 下出现 libhello.so

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5. 启动模拟器,推送 libhello.so 和 inject 到虚拟机里

我启动的模拟器配置如下

Name: android-helloworld

CPU/ABI: ARM (armeabi-v7a)

Path: C:\Users\Administrator\.android\avd\android-helloworld.avd

Target: Android 4.4.2 (API level 19)

Skin: HVGA

hw.dPad: no

hw.accelerometer: yes

hw.device.name: Nexus 7

vm.heapSize: 32

skin.dynamic: no

hw.device.manufacturer: Google

hw.gps: yes

hw.audioInput: yes

hw.cpu.model: cortex-a8

tag.id: default

hw.mainKeys: no

hw.camera.front: none

hw.lcd.density: 213

hw.device.hash2: MD5:d3c9ed02af441ec949711439b9a48b85

hw.ramSize: 1024

hw.trackBall: no

hw.battery: yes

hw.sdCard: no

tag.display: Default

hw.keyboard: yes

hw.sensors.proximity: no

disk.dataPartition.size: 200M

hw.sensors.orientation: yes

avd.ini.encoding: ISO-8859-1

使用adb push命令推送

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6. adb shell 进入模拟器运行

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先将动态库和可执行程序设置权限777,在另一个终端启动测试进程 target, 然后用 inject 注入该进程, 第三个终端用 adb logcat 查看日志,如下

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打印出来  Hello I‘m parameter! 证明 hook_entry 函数执行成功了。

 

最后给出 inject.c 的代码

 

#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>
#define __arm__
#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 *)&params[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__)
#if 0
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;
}
#endif
#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;
    struct pt_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, &regs) == -1)
        goto exit;

    /* save original registers */
    memcpy(&original_regs, &regs, 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, &regs) == -1)
        goto exit;

    map_base = ptrace_retval(&regs);

    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, &regs) == -1)
        goto exit;

    void * sohandle = ptrace_retval(&regs);

#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) == -1)
        goto exit;

    void * hook_entry_addr = ptrace_retval(&regs);
    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, &regs) == -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, &regs) == -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("/system/bin/surfaceflinger");
    target_pid = atoi(argv[1]);
    if (-1 == target_pid) {
        printf("Can‘t find the process\n");
        return -1;
    }
    //target_pid = find_pid_of("/data/test");
    inject_remote_process(target_pid, "/data/local/tmp/libhello.so", "hook_entry",  "I‘m parameter!", strlen("I‘m parameter!"));
    return 0;
}

 

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