Messages in this thread | | | Date | Tue, 28 Dec 1999 19:02:36 -0000 (GMT) | From | Anton Ivanov <> | Subject | Re: Unexecutable stack |
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On 28-Dec-1999 Adam J. Richter wrote: > If the problem with making the stack unexecutable is a few > pieces of trampoline code, then how about just modifying the few > programs that use this code to mprotect the stack when they actually > need it to be executable? Even if these programs simply made their > entire stack area executable at initialization time, at least the > other programs would be considerably more secure. > > I believe this change would eliminate about half of the root > exploits that I see reports of, or, to put it more dramatically, it > would eliminate more exploits than all other improvements combined.
1. It is a stick with two ends. You become slow lame and lazy and forget to update (under the idea: whatever, nobody can exploit it anyway). Have a look at DGUX. It used to have a non-exec stack in the 3.x days. As a result most of the exploits (even elementary ones like lpd were not fixed). Then in 4.x the stack had to go executable again. And then it became fun (actually I am slightly incorrect here because the fun officially began after some kid posted general purpose shellcode for alpha).
2. Trampolines: A: the few programs are f.e. glibc itself or docs on solar designer patches are wrong. B: solar designer patches have been doing this for quite a while.
3. If at least solar designer's and andrew tridgel's patches (pipes in proc, etc) will finally make it into the mainstream kernel it will be very very nice.
My 0.02$
- ---------------------------------- Anton R. Ivanov IP Enginteer Level3 Communications RIPE: ARI2-RIPE E-Mail: Anton Ivanov <aivanov@eu.level3.net> @*** Gerrold's Laws of Infernal Dynamics (No 2 of 3) An object at rest will always be in the wrong place.
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