Question

我正在尝试在linux上对vsftpd服务器进程进行ptrace，以便能够在vsftpd进程进行系统调用时获得控制权。我启动vsftpd进程并将此进程id作为命令行传递给跟踪vsftpd的以下程序。

然而，当我运行以下程序时，它只是挂起并且不打印任何内容。任何人都可以指出可能出错的地方？非常感谢你的帮助!!

#include <sys/ptrace.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <linux/user.h> 
#include <sys/syscall.h>   /* For SYS_write etc */
#include<sys/reg.h>
int main(int argc,char* argv[])
{   pid_t child;
long orig_eax, eax;
long params[3];
int status;
int insyscall = 0;
child = atoi(argv[1]);
ptrace(PTRACE_ATTACH,child,NULL,NULL);
   while(1) {
      wait(&status);
      if(WIFEXITED(status))
          break;
      orig_eax = ptrace(PTRACE_PEEKUSER,
                 child, 4 * ORIG_EAX, NULL);

    if(orig_eax == __NR_clone || orig_eax == __NR_open || orig_eax == __NR_write)
        { 
if(insyscall == 0) {
            /* Syscall entry */
            insyscall = 1;
            params[0] = ptrace(PTRACE_PEEKUSER,
                               child, 4 * EBX,
                               NULL);
            params[1] = ptrace(PTRACE_PEEKUSER,
                               child, 4 * ECX,
                               NULL);
            params[2] = ptrace(PTRACE_PEEKUSER,
                               child, 4 * EDX,
                               NULL);
    if(orig_eax == __NR_clone)
    {
        printf("\nClone");
    }
    else if(orig_eax == __NR_open)
        printf("\nOpen");
    else if(orig_eax == __NR_write)
        printf("\nWrite");
            printf(" called with "
                   "%ld, %ld, %ld\n",
                   params[0], params[1],
                   params[2]);
            }
      else { /* Syscall exit */
            eax = ptrace(PTRACE_PEEKUSER,
                         child, 4 * EAX, NULL);
                printf("Returned "
                       "with %ld\n", eax);
                insyscall = 0;
            }
        }
        ptrace(PTRACE_SYSCALL,
               child, NULL, NULL);
    }

 return 0;
}

Answer 1

您需要拥有跟踪VSFTPD的权限。以root身份运行它。要进行测试，请将ptrace(PTRACE_ATTACH,child,NULL,NULL);的结果放入变量并打印，即

long result = ptrace(PTRACE_ATTACH,child,NULL,NULL);
printf("%ld",result);

如果结果== -1，在我的系统上，我没有权限。如果结果== 0，我会这样做。

ptrace附加到vsftpd挂起

1 个答案: