Messages in this thread | | | Date | Mon, 23 Apr 2018 20:00:09 +0200 | From | Joerg Roedel <> | Subject | Re: [PATCH 27/37] x86/mm/pti: Keep permissions when cloning kernel text in pti_clone_kernel_text() |
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On Mon, Apr 23, 2018 at 10:06:20AM -0700, Kees Cook wrote: > Why are there R/W text mappings in this range? I find that to be > unexpected. Shouldn't CONFIG_DEBUG_WX already complain if that were > true?
It actually complains, I have seen that with the base-kernel too. I guess this is because of the different mark_rodata_ro() and mark_nxdata_nx() implementations between 32 and 64 bit. They actually protect different regions, I think one reason is that some regions are not hupe-page aligned on 32 bit and doing the right protections as on 64 bit would require to split the 2M mappings into 4k mappings.
But I havn't looked deeper into that and whether it can be unified and fixed for 32 bit. It is probably out-of-scope for this patch-set.
Regards,
Joerg
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