背景

反调试的方法很多，不过由于android系统是开源的，所以反调试其实也不是很神秘的东西。
下面是常见的也是很多厂商都在使用，包括我们项目组也在使用的。多个方案相互结合可以实现更好反调试。

1.1 ptrace自己,使得android_server附加不上

void anti_ptrace()
{
ptrace(PTRACE_TRACEME, 0, 0, 0);
}

1.2. 检测Tracepid的值

void anti_Tracepid()
{
try
{
const int bufsize = 1024;
char filename[bufsize];
char line[bufsize];
int pid = getpid();
sprintf(filename, “/proc/%d/status”, pid);
FILE* fd = fopen(filename, “r”);
if (fd !=NULL)
{
while (fgets(line, bufsize, fd))
{
if (strncmp(line, “TracerPid”, 9) == 0)
{
int statue = atoi(&line[10]);
if (statue != 0)
{
fclose(fd);
int ret = kill(pid, SIGKILL);
}
break;
}
}
fclose(fd);
} else
{
// LOGD(“open %s fail…”, filename);
}
} catch (…)
{

}

}

1.3 检测端口号，针对android_server这个端口号

void anti_serverport() {
const int bufsize=512;
char filename[bufsize];
char line[bufsize];
int pid =getpid();
sprintf(filename,"/proc/net/tcp");
FILE* fd=fopen(filename,“r”);
if(fd!=NULL){
while(fgets(line,bufsize,fd)){
if (strncmp(line, “5D8A”, 4)==0){
int ret = kill(pid, SIGKILL);
}
}
}
fclose(fd);

}

1.4 检测这些调试进程的名字

void anti_processstatus(){
const int bufsize = 1024;
char filename[bufsize];
char line[bufsize];
char name[bufsize];
char nameline[bufsize];
int pid = getpid();
//先读取Tracepid的值
sprintf(filename, “/proc/%d/status”, pid);
FILE *fd=fopen(filename,“r”);
if(fd!=NULL){
while(fgets(line,bufsize,fd)){
if(strstr(line,“TracerPid”)!=NULL)
{
int statue =atoi(&line[10]);
if(statue!=0){
sprintf(name,"/proc/%d/cmdline",statue);
FILE *fdname=fopen(name,“r”);
if(fdname!= NULL){
while(fgets(nameline,bufsize,fdname)){
if(strstr(nameline,“android_server”)!=NULL){
int ret=kill(pid,SIGKILL);
}
}
}
fclose(fdname);
}
}
}
}
fclose(fd);
}

1.5. 检测常放目录：/data/local/tmp

void anti_localtmp(){
int pid=getpid();
const int bufsize=1024;
char line[bufsize];
char filename[bufsize];
sprintf(filename,"/data/local/tmp");
FILE *fd=fopen(filename,“r”);
if(fd!=NULL){
while(fgets(line,bufsize,fd)){
if(strstr(line,“android_server”)!=NULL){
int ret=kill(pid,SIGKILL);
}
}
}
fclose(fd);
}

1.6 检测break point指令

unsigned long GetLibAddr() {
unsigned long ret = 0;
char name[] = “libptrace.so”;
char buf[4096], *temp;
int pid;
FILE *fp;
pid = getpid();
sprintf(buf, “/proc/%d/maps”, pid);
fp = fopen(buf, “r”);
if (fp == NULL) {
puts(“open failed”);
goto _error;
}
while (fgets(buf, sizeof(buf), fp)) {
if (strstr(buf, name)) {
temp = strtok(buf, “-”);
ret = strtoul(temp, NULL, 16);
break;
}
}
_error: fclose(fp);
return ret;
}

1.7 通过使用Linux inotify特性来对文件的读写，以及打开等权限进行监控

void anti_debug06() {
int ret, len, i;
int pid6 = getpid();
const int MAXLEN = 2048;
char buf[1024];
char readbuf[MAXLEN];
int fd, wd;
fd_set readfds;
fd = inotify_init();
sprintf(buf, “/proc/%d/maps”, pid6);
wd = inotify_add_watch(fd, buf, IN_ALL_EVENTS);
if(wd>=0){
while (1) {
i = 0;
FD_ZERO(&readfds);//使得readfds清零
FD_SET(fd, &readfds);//将fd加入readfds集合
ret = select(fd + 1, &readfds, 0, 0, 0);
if(ret==-1){
break;
}
if (ret) {
len = read(fd, readbuf, MAXLEN);
while (i < len) {
struct inotify_event *event = (struct inotify_event *) &readbuf[i];
if ((event->mask & IN_ACCESS) || (event->mask & IN_OPEN)) {
int ret = kill(pid6, SIGKILL);
return;
}
i += sizeof(struct inotify_event) + event->len;
}
}

}
}
inotify_rm_watch(fd, wd);
close(fd);

}

1.8.检测被调试代码的前后时间的差异；

int gettimeofday(struct timeval *tv,struct timezone *tz);
void anti_debug07(){
int pid=getpid();
struct timeval t1;
struct timeval t2;
struct timezone tz;
gettimeofday(&t1,&tz);
gettimeofday(&t2,&tz);
// int timeoff=gettimeofday(&t1,0)-gettimeofday(&t2,0);
int timeoff=(t2.tv_sec)-(t1.tv_sec);
if(timeoff>1){
int ret=kill(pid,SIGKILL);
return ;
}
}