Re: Doubt: core not dumped when binary give up root privileges.

From: Alan Cox (alan_at_lxorguk.ukuu.org.uk)
Date: 08/26/03

  • Next message: David Howells: "Re: authentication / encryption key retention" 
    To: Alexandre Pereira Nunes <alex@PolesApart.wox.org>
Date:	26 Aug 2003 17:04:08 +0100

    On Gwe, 2003-08-22 at 20:25, Alexandre Pereira Nunes wrote:
    > The program explicitly sets RLIMIT_CORE to RLIM_INFINITY when still
    > running with uid 0.

    The kernel assumes a core image from something that was priviledged may
    be unsafe.

    > If instead of calling the program as root, I call it from the non-priv
    > uid in question, if it crashes, it dumps core on the mentioned dir.
    > That's the desired behaviour, since I can then take the core and debug.
    > But if I run it as root (in fact, I would have to), and it crashes (or
    > is forced to ,by means of kill -SEGV), after it gives up root
    > credentials, it won't leave a core dump file, which in turn means I
    > cannot debug it later.
    >
    > Any ideas?

    2.4-ac has support for enabling setuid core dumps and setting the dump
    path, so you can write such dumps to /root/dumps and the kernel will
    make them root accessible only.

    The 2.6 test tree and Marcelo 2.4 don't currently support this

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  • Next message: David Howells: "Re: authentication / encryption key retention"

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