iOS安全防护系列之重签名防护与sysctl反调试详解

void checkCodesign(NSString *id){
 // 描述文件路径
 NSString *embeddedPath = [[NSBundle mainBundle] pathForResource:@"embedded" ofType:@"mobileprovision"];
 // 读取application-identifier 注意描述文件的编码要使用:NSASCIIStringEncoding
 NSString *embeddedProvisioning = [NSString stringWithContentsOfFile:embeddedPath encoding:NSASCIIStringEncoding error:nil];
 NSArray *embeddedProvisioningLines = [embeddedProvisioning componentsSeparatedByCharactersInSet:[NSCharacterSet newlineCharacterSet]];
 
 for (int i = 0; i < embeddedProvisioningLines.count; i++) {
 if ([embeddedProvisioningLines[i] rangeOfString:@"application-identifier"].location != NSNotFound) {
  
  NSInteger fromPosition = [embeddedProvisioningLines[i+1] rangeOfString:@"<string>"].location+8;
  
  NSInteger toPosition = [embeddedProvisioningLines[i+1] rangeOfString:@"</string>"].location;
  
  NSRange range;
  range.location = fromPosition;
  range.length = toPosition - fromPosition;
  
  NSString *fullIdentifier = [embeddedProvisioningLines[i+1] substringWithRange:range];
  NSArray *identifierComponents = [fullIdentifier componentsSeparatedByString:@"."];
  NSString *appIdentifier = [identifierComponents firstObject];
 
  // 对比签名ID
  if (![appIdentifier isEqual:id]) {
  //exit
  asm(
   "mov X0,#0n"
   "mov w16,#1n"
   "svc #0x80"
   );
  }
  break;
 }
 }
}

#import <sys/sysctl.h>
bool checkDebugger(){
 //控制码
 int name[4];//放字节码-查询信息
 name[0] = CTL_KERN;//内核查看
 name[1] = KERN_PROC;//查询进程
 name[2] = KERN_PROC_PID; //通过进程id查进程
 name[3] = getpid();//拿到自己进程的id
 //查询结果
 struct kinfo_proc info;//进程查询信息结果
 size_t info_size = sizeof(info);//结构体大小
 int error = sysctl(name, sizeof(name)/sizeof(*name), &info, &info_size, 0, 0);
 assert(error == 0);//0就是没有错误
 
 //结果解析 p_flag的第12位为1就是有调试
 //p_flag 与 P_TRACED =0 就是有调试
 return ((info.kp_proc.p_flag & P_TRACED) !=0); 
}

if (checkDebugger()) {
 asm("mov X0,#0n"
  "mov w16,#1n"
  "svc #0x80"
  );
 }

//原始函数的地址
int (*sysctl_p)(int *, u_int, void *, size_t *, void *, size_t);

//自定义函数
int mySysctl(int *name, u_int namelen, void *info, size_t *infosize, void *newinfo, size_t newinfosize){
 if (namelen == 4
 && name[0] == CTL_KERN
 && name[1] == KERN_PROC
 && name[2] == KERN_PROC_PID
 && info
 && (int)*infosize == sizeof(struct kinfo_proc))
 {
 int err = sysctl_p(name, namelen, info, infosize, newinfo, newinfosize);
 //拿出info做判断
 struct kinfo_proc * myInfo = (struct kinfo_proc *)info;
 if((myInfo->kp_proc.p_flag & P_TRACED) != 0){
  //使用异或取反
  myInfo->kp_proc.p_flag ^= P_TRACED;
 }
 
 
 return err;
 }
 
 return sysctl_p(name, namelen, info, infosize, newinfo, newinfosize);
}


+(void)load
{
 //交换
 rebind_symbols((struct rebinding[1]){{"sysctl",mySysctl,(void *)&sysctl_p}}, 1);
}

 asm("mov X0,#0n"
  "mov w16,#1n"
  "svc #0x80"
  );