[Libguestfs] [PATCH] Add a test for an executable stack in libguestfs.so
Richard W.M. Jones
rjones at redhat.com
Wed Aug 5 10:58:10 UTC 2009
On Wed, Aug 05, 2009 at 11:45:02AM +0100, Matthew Booth wrote:
> I've updated the patch. It's now in regressions, and checks both
> libguestfs.so and the guest daemon. It occurs to me that it's the
> daemon that's would get an executable stack from the specific patch
> I posted the other day. However, would this actually matter
> specifically for the daemon?
Duh yes, you're right. I was checking the wrong executable.
$ readelf -l daemon/guestfsd
[...]
GNU_STACK 0x0000000000000000 0x0000000000000000 0x0000000000000000
0x0000000000000000 0x0000000000000000 RWE 8
So your patch *does* make the daemon stack executable.
Does it matter for the daemon? Probably yes. We should avoid
allowing code to be injected into the appliance. For example if there
was a malicious string which was passed into libguestfs from user
input, then the additional stack guards would be our last line of
defence.
Also rpmlint will give a warning about this.
NAK I'm afraid. However just hoisting those functions out so they are
not nested should make it OK. Don't forget the other two things I
raised in the original review.
Rich.
--
Richard Jones, Emerging Technologies, Red Hat http://et.redhat.com/~rjones
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