Messages in this thread | | | Date | Tue, 25 Sep 2007 19:05:06 +0200 (CEST) | From | Jan Engelhardt <> | Subject | Re: Chroot bug |
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On Sep 25 2007 19:00, Miloslav Semler wrote: >> > This does not help. Let's try: >> > chroot somewhere >> > mkdir foo >> > fd = open / >> > chroot foo >> > >> >> ('fd' implicitly closed and chdir to /foo) >> > Really? Try it. I am sure, that this works. You can create directory in chroot > and break chroot by this. fd is not closed, because linux doesn't close > descriptors by chroot syscall. this can be done every time if you have > CAP_SYS_CHROOT.
In case you have not followed my earlier email, I'll repost:
|>> So what? Just do this: chdir into the root after chroot. |> |> I don't think so. His exploit just got me all the way out of a |> chroot within a chroot within a chroot, inclusive of lots of |> chdirs. |> | |Close all fds that point to directories outside the root ;-)
Perhaps that was formulated a bit sloppy. It of course means "On chroot(2), implicitly close all FDs that point outside." - 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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