Messages in this thread | | | Date | Fri, 26 Sep 2003 19:24:49 +0200 (CEST) | From | Ingo Molnar <> | Subject | Re: [patch] updated exec-shield patch, 2.4/2.6 -G3 |
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On Fri, 26 Sep 2003 Valdis.Kletnieks@vt.edu wrote:
> On Fri, 26 Sep 2003 14:28:54 +0200, Ingo Molnar <mingo@elte.hu> said: > > > against vanilla 2.6.0-test5: > > > > redhat.com/~mingo/exec-shield/exec-shield-2.6.0-test5-G2 > > Ingo, you rock. ;) I'm using a fairly current Rawhide here (within last 2 > weeks or so). > > Applied with 2 or 3 minor conflicts and a few fuzz/delta messages > against -test5-mm4 (I have a refactored patch if anybody is interested). > It booted OK, seems to be working well enough that e-mail and XFree > (even with the evil binary NVidia driver) are functional.
btw., i have a patch against Linus' latest, -bk12 too:
redhat.com/~mingo/exec-shield/exec-shield-2.6.0-test5-bk12-G2
> I'm assuming it's this GCC change in Rawhide: > > * Wed Jun 04 2003 Jakub Jelinek <jakub@redhat.com> 3.3-4 > > - mark object files with .note.GNU-stack notes whether they > need or don't need executable stack
yes. The kernel ELF loader now detects this PT_GNU_STACK program header entry and acts upon it. (when using the setting of 1.)
> (and another at 3.3-5). Has the current Rawhide been recompiled with this > support, or should I stick with '2' and use setarch for things that fail?
it's quit easy to check: with a setting of 1, does 'cat /proc/self/maps' show a randomized layout, while 'setarch i386 cat /proc/self/maps' shows a regular layout? If /bin/cat defaults to exec-shield even with a setting of 1 then everything's recompiled.
in fact with glibc-2.3.2-92 and later ld.so will revert a non-executable stack to executable if a binary loads a DSO that needs an executable stack. 'tuxracer' is one such very important example :-)
> Now to go build a testcase program and try to shellcode it. ;)
i see the smiley - but it would truly be interesting to try to find the boundaries of exec-shield and try to exploit it.
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