Re: [PATCH V5] x86: NX protection for kernel data

[David Howells <dhowells@redhat.com>]

Siarhei Liakh <sliakh.lkml@gmail.com> wrote:

> This patch expands functionality of CONFIG_DEBUG_RODATA to set main
> (static) kernel data area as NX.
> The following steps are taken to achieve this:
> 1. Linker script is adjusted so .text always starts and ends on a page boundary
> 2. Linker script is adjusted so .rodata and .data always start and
> end on a page boundary
> 3. void mark_nxdata_nx(void) added to arch/x86/mm/init.c with actual
> functionality: NX is set for all pages from _etext through _end.
> 4. mark_nxdata_nx() called from free_initmem() (after init has been released)
> 5. free_init_pages() sets released memory NX in arch/x86/mm/init.c
> 
> The patch have been developed for Linux 2.6.31-rc7 x86 by Siarhei Liakh
> <sliakh.lkml@gmail.com> and Xuxian Jiang <jiang@cs.ncsu.edu>.
> 
> V1:  initial patch for 2.6.30
> V2:  patch for 2.6.31-rc7
> V3:  moved all code into arch/x86, adjusted credits
> V4:  fixed ifdef, removed credits from CREDITS
> V5:  fixed an address calculation bug in mark_nxdata_nx()
> ---
> 
> Signed-off-by: Siarhei Liakh <sliakh.lkml@gmail.com>
> Signed-off-by: Xuxian Jiang <jiang@cs.ncsu.edu>

That seems to fix the problem, thanks.

Acked-by: David Howells <dhowells@redhat.com>