Messages in this thread | | | Date | Sun, 29 Jun 2003 15:27:25 +0100 | From | viro@parcelfa ... | Subject | Re: [RFC][PATCH-2.4] Prevent mounting on ".." |
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On Sun, Jun 29, 2003 at 04:20:47PM +0200, Willy TARREAU wrote: > No, it works only with "..", and not with "." ! I don't know why, I believe > it's because the process is still attached to the old FS when mounting on ".".
So? chdir around and you'll get to the covering directory.
> > If attacker can mount of chroot - you've LOST. Already. End of story. > > To me, it seems this is the *only* remaining case in an *empty* read-only > directory. The fact is that the attacker needs at least a mount point to mount > something. Not providing him one is efficient, but here he can only exploit > "..". > > Please reconsider the question, Al, because I really think that with this, we > can get reliable jails for network daemons which don't need file access at all.
Sigh... We _can't_ do that via chroot(). Please, stop fooling yourself - if attacker gets control over root process, the fight is over. In particular, attacker can chmod your read-only directory and/or remount the thing. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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