Re: [Libguestfs] [PATCH] Add a test for an executable stack in libguestfs.so

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.