Re: sys_chroot+sys_fchdir Fix

From: David Newall
Date: Tue Sep 25 2007 - 09:59:09 EST


Serge E. Hallyn wrote:
Quoting David Newall (david@xxxxxxxxxxxxxxx):
Serge E. Hallyn wrote:
Quoting David Newall (david@xxxxxxxxxxxxxxx):
It might be tidy if pivot_root could be used (instead of a hack based on a chroot bug), but it'd still be unportable.
It can.

Please re-read my previous msg.
I read it. Currently pivot_root can't be used to affect a single process.

No. If you unshare your mounts namespace immediately before pivot_root,
then pivot_root will only affect that single process.

Bugger. You're right, I didn't read your previous message; I thought I had but I was wrong.

unshare(CLONE_NEWNS);
chdir(new_dir);
pivot_root(new_dir, oldroot);


After further RTFMing, and assuming "any processes or threads which use the old root directory" means what you imply, and surely it does, then I agree: pivot_root already does the job. Does anybody still need to use a bug in chroot?
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/