Messages in this thread | | | Date | Sun, 6 Feb 2005 13:02:44 +0100 | From | Ingo Molnar <> | Subject | Re: [PROPOSAL/PATCH] Remove PT_GNU_STACK support before 2.6.11 |
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* Arjan van de Ven <arjan@infradead.org> wrote:
> > [...] when the program has trampolines and has PT_GNU_STACK > > header with an E bit on the stack it still won't get an executable > > heap by default (this is what broke grub) > > this I can fix easy, see the patch below > > the problem is in the read_implies_exec() design, it passed in "does > it have a PT_GNU_STACK flag" not the value. Easy fix.
> So I rather see the patch below merged instead; it fixes the worst > problems (RWE not marking the heap executable) while keeping this > useful feature enabled. > > Signed-off-by: Arjan van de Ven <arjan@infradead.org>
looks good.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
(I'd like to stress that this problem only affects packages _recompiled_ with new gcc, running on NX capable CPUs - legacy apps or CPUs are in no way affected. Also, even with a recompile, apps/kernels/distros have a number of other options as well even without this kernel fix, of varying granularity: to use the setarch utility, to set the READ_IMPLIES_EXEC personality bit within the code, or to pass in the noexec=off kernel commandline option, or to add a oneliner patch to their heap of 1500+ kernel patches, or to fix the application. Also, with Arjan's patch applied, the execstack utility can be used to remark the binary permanently, if needed.)
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