Question

Basically I want to execute a shell command inside a jailed process. When I try the below code(both as a normal user & root user), it produced no output

if(!(pid=fork)){
   chroot("./jail_folder");
   chdir("/");

   execl("/bin/ls","ls",NULL);
}

I tried the perror() function and it gave me a “No such file or directory” error.
Is it possible to run a shell command in a jailed process? If so, how do we do that?

Answer 1

Yes, it is possible, but you have to make it accessible to the jail (typically, it means copying the desired program + all its libraries to the jail; symlinking wouldn’t work, hardlinking is OK). Otherwise, it’s no surprise that if you confine a program to part of the directory tree without /bin, you can’t access /bin/ls.