Android中实现对/system/bin/surfaceflinger进程进行拦截和注入

对于Android for arm上的so注入（inject）和挂钩（hook），网上已有牛人给出了代码inject。由于实现中的ptrace函数是依赖于平台的，所以不经改动只能用于arm平台。本文将之扩展了一下，使它能够通用于Android的x86和arm平台。Arm平台部分基本重用了inject中的代码，其中因为汇编不好移植且容易出错，所以把shellcode.s用ptrace_call替换掉了，另外保留了mmap，用来传字符串参数，当然也可以通过栈来传，但栈里和其它东西混一起，一弄不好就会隔儿了，所以还是保险点好。最后注意设备要root。

还有就是要在Linux中配置一下NDK编译环境呀~~(这个可以google了~~)

首先创建目录及文件：

文件夹：jni

文件：
    inject.c
    Android.mk
    Application.mk

(说明：由于NDK编译的条件限制，所以我们需要创建的jni文件夹，当然这个文件的名字必须是jni)

注入的核心源代码：

inject.c

#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, &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");
    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/libhello.so", "hook_entry",  "I'm parameter!", strlen("I'm parameter!"));
    return 0;
} 

注意上面的/system/bin/surfaceflinger进程我随手写的，你的设备上不一定有。没有的话挑其它的也行，前提是ps命令里能找到。

Android.mk:

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)  

Application.mk:

APP_ABI := x86 armeabi-v7a  

运行nkd-build编译成生x86和arm平台下的可执行文件：

再来生成要注入的so，创建目录及文件：
jni
    suf.c
    Android.mk

Application.mk

suf.c:

#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;
}  

Android.mk:

LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_LDLIBS += -L$(SYSROOT)/usr/lib -llog
#LOCAL_ARM_MODE := arm
LOCAL_MODULE    := suf
LOCAL_SRC_FILES := suf.c
include $(BUILD_SHARED_LIBRARY)  

Application.mk:

APP_ABI := x86 armeabi-v7a  

运行nkd-build编译成生x86和arm平台下的so：

然后就可以跑起来试试了，连接root过的Android设备或者打开模拟器。将inject和libhello.so拷入设备，设执行权限，执行：
先看看被注入进程（surfaceflinger）的mmap，可以看到我们的so已经被加载了，紧接着的那一块就是我们mmap出来的：

从logcat中也可以看到so注入成功，并且以被注入进程的身份执行了so中的代码.

将编译好的文件拷贝到设备的data目录(这里不一定要拷贝到data目录下面，这个可以看自己的需要了)下面：

adb push inject /data/

adb push libsuf.so /data/

然后修改一下文件的权限

chmod 777 inject

然后运行inject,同时我们可以查询一下/system/bin/surfaceflinger进程信息，可以看到，我们将libsuf.so注入到了此进程中.

简单的注入成功，现在我们再来做一个实验，就是应用这套机制来截获surfaceflinger中的eglSwapBuffers调用，然后用我们自己的函数来替换掉原来的eglSwapBuffers调用。关于截系统中的函数调用网上有例子，这里依葫芦画瓢。首先将suf.c改下：

#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <android/log.h>
#include <EGL/egl.h>
#include <GLES/gl.h>
#include <elf.h>
#include <fcntl.h>
#include <sys/mman.h>  

#define LOG_TAG "DEBUG"
#define LOGD(fmt, args...) __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, fmt, ##args)    

EGLBoolean (*old_eglSwapBuffers)(EGLDisplay dpy, EGLSurface surf) = -1;  

EGLBoolean new_eglSwapBuffers(EGLDisplay dpy, EGLSurface surface)
{
    LOGD("New eglSwapBuffers\n");
    if (old_eglSwapBuffers == -1)
        LOGD("error\n");
    return old_eglSwapBuffers(dpy, surface);
}  

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;
}  

#define LIBSF_PATH  "/system/lib/libsurfaceflinger.so"
int hook_eglSwapBuffers()
{
    old_eglSwapBuffers = eglSwapBuffers;
    LOGD("Orig eglSwapBuffers = %p\n", old_eglSwapBuffers);
    void * base_addr = get_module_base(getpid(), LIBSF_PATH);
    LOGD("libsurfaceflinger.so address = %p\n", base_addr);    

    int fd;
    fd = open(LIBSF_PATH, O_RDONLY);
    if (-1 == fd) {
        LOGD("error\n");
        return -1;
    }    

    Elf32_Ehdr ehdr;
    read(fd, &ehdr, sizeof(Elf32_Ehdr));    

    unsigned long shdr_addr = ehdr.e_shoff;
    int shnum = ehdr.e_shnum;
    int shent_size = ehdr.e_shentsize;
    unsigned long stridx = ehdr.e_shstrndx;      

    Elf32_Shdr shdr;
    lseek(fd, shdr_addr + stridx * shent_size, SEEK_SET);
    read(fd, &shdr, shent_size);      

    char * string_table = (char *)malloc(shdr.sh_size);
    lseek(fd, shdr.sh_offset, SEEK_SET);
    read(fd, string_table, shdr.sh_size);
    lseek(fd, shdr_addr, SEEK_SET);      

    int i;
    uint32_t out_addr = 0;
    uint32_t out_size = 0;
    uint32_t got_item = 0;
    int32_t got_found = 0;    

    for (i = 0; i < shnum; i++) {
        read(fd, &shdr, shent_size);
        if (shdr.sh_type == SHT_PROGBITS) {
            int name_idx = shdr.sh_name;
            if (strcmp(&(string_table[name_idx]), ".got.plt") == 0
                    || strcmp(&(string_table[name_idx]), ".got") == 0) {
                out_addr = base_addr + shdr.sh_addr;
                out_size = shdr.sh_size;
                LOGD("out_addr = %lx, out_size = %lx\n", out_addr, out_size);    

                for (i = 0; i < out_size; i += 4) {
                    got_item = *(uint32_t *)(out_addr + i);
                    if (got_item  == old_eglSwapBuffers) {
                        LOGD("Found eglSwapBuffers in got\n");
                        got_found = 1;  

                        uint32_t page_size = getpagesize();
                        uint32_t entry_page_start = (out_addr + i) & (~(page_size - 1));
                        mprotect((uint32_t *)entry_page_start, page_size, PROT_READ | PROT_WRITE);
                        *(uint32_t *)(out_addr + i) = new_eglSwapBuffers;    

                        break;
                    } else if (got_item == new_eglSwapBuffers) {
                        LOGD("Already hooked\n");
                        break;
                    }
                }
                if (got_found)
                    break;
            }
        }
    }      

    free(string_table);
    close(fd);
}    

int hook_entry(char * a){
    LOGD("Hook success\n");
    LOGD("Start hooking\n");
    hook_eglSwapBuffers();
    return 0;
}  

其实这种查找方法有点简单粗暴，要是正式应用的话可以在动态符号表中查找这个符号的got地址。
接着Android.mk改为：

LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_LDLIBS += -L$(SYSROOT)/usr/lib -llog -lEGL
#LOCAL_ARM_MODE := arm
LOCAL_MODULE    := hello
LOCAL_SRC_FILES := hello.c
include $(BUILD_SHARED_LIBRARY) 

Application.mk :

APP_ABI := x86 armeabi-v7a
APP_PLATFORM := android-14  

运行ndk-build编译
和上面一样运行，查看logcat，我们可以看到surfaceflinger中调用eglSwapBuffers的地址已被替换成我们的版本：
D/INJECT  ( 2231): [+] Injecting process: 1728  
D/INJECT  ( 2231): [+] get_remote_addr: local[b7e4f000], remote[b7e73000]  
D/INJECT  ( 2231): [+] Remote mmap address: b7e9fe32  
D/INJECT  ( 2231): [+] Calling mmap in target process.  
D/INJECT  ( 2231): [+] Target process returned from mmap, return value=b4f1c000, pc=0   
D/INJECT  ( 2231): [+] get_remote_addr: local[b7f00000], remote[b7f7e000]  
D/INJECT  ( 2231): [+] get_remote_addr: local[b7f00000], remote[b7f7e000]  
D/INJECT  ( 2231): [+] get_remote_addr: local[b7f00000], remote[b7f7e000]  
D/INJECT  ( 2231): [+] get_remote_addr: local[b7f00000], remote[b7f7e000]  
D/INJECT  ( 2231): [+] Get imports: dlopen: b7f84f50, dlsym: b7f84fd0, dlclose: b7f84de0, dlerror: b7f84dc0  
D/INJECT  ( 2231): [+] Calling dlopen in target process.  
D/INJECT  ( 2231): [+] Target process returned from dlopen, return value=b7f995ec, pc=0   
D/INJECT  ( 2231): [+] Calling dlsym in target process.  
D/INJECT  ( 2231): [+] Target process returned from dlsym, return value=b4f17e10, pc=0   
D/INJECT  ( 2231): hook_entry_addr = 0xb4f17e10  
D/DEBUG   ( 1728): Hook success  
D/DEBUG   ( 1728): Start hooking  
D/DEBUG   ( 1728): Orig eglSwapBuffers = 0xb7d4a9c0  
D/DEBUG   ( 1728): libsurfaceflinger.so address = 0xb7f22000  
D/DEBUG   ( 1728): out_addr = b7f7aff4, out_size = 624  
D/DEBUG   ( 1728): Found eglSwapBuffers in got  
...  
D/DEBUG   ( 1728): New eglSwapBuffers  
D/DEBUG   ( 1728): New eglSwapBuffers  
D/DEBUG   ( 1728): New eglSwapBuffers  
...  

Demo下载地址：http://download.csdn.net/detail/jiangwei0910410003/7926427

这篇文章就简单介绍了如何将对surfaceflinger进程进行注入和拦截的操作。这个还是很有用的，后续我们还会对system_process进程进行注入和拦截，那时候还会参考这篇文章。。