Messages in this thread | | | Date | Sun, 6 Feb 2005 13:25:07 +0100 | From | Ingo Molnar <> | Subject | Re: [PROPOSAL/PATCH] Remove PT_GNU_STACK support before 2.6.11 |
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* Ingo Molnar <mingo@elte.hu> 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)
> > 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.)
another, purely userspace solution is to add an execstack.c flag that clears the PT_GNU_STACK ELF program header and changes it to e.g. PT_NULL. That makes it a 'legacy' binary for the purposes of the kernel.
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