This is a note to let you know that I have just added a patch titled
x86/mm: Set NX on gap between __ex_table and rodata
to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree
which can be found at:
http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue
This patch is scheduled to be released in version 3.16.7-ckt19.
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Luis
------
>From 86d789f65722a825ea614b292842168844db39a6 Mon Sep 17 00:00:00 2001
From: Stephen Smalley <s...@tycho.nsa.gov>
Date: Thu, 1 Oct 2015 09:04:22 -0400
Subject: x86/mm: Set NX on gap between __ex_table and rodata
commit ab76f7b4ab2397ffdd2f1eb07c55697d19991d10 upstream.
Unused space between the end of __ex_table and the start of
rodata can be left W+x in the kernel page tables. Extend the
setting of the NX bit to cover this gap by starting from
text_end rather than rodata_start.
Before:
---[ High Kernel Mapping ]---
0xffffffff80000000-0xffffffff81000000 16M
pmd
0xffffffff81000000-0xffffffff81600000 6M ro PSE GLB
x pmd
0xffffffff81600000-0xffffffff81754000 1360K ro GLB
x pte
0xffffffff81754000-0xffffffff81800000 688K RW GLB
x pte
0xffffffff81800000-0xffffffff81a00000 2M ro PSE GLB
NX pmd
0xffffffff81a00000-0xffffffff81b3b000 1260K ro GLB
NX pte
0xffffffff81b3b000-0xffffffff82000000 4884K RW GLB
NX pte
0xffffffff82000000-0xffffffff82200000 2M RW PSE GLB
NX pmd
0xffffffff82200000-0xffffffffa0000000 478M
pmd
After:
---[ High Kernel Mapping ]---
0xffffffff80000000-0xffffffff81000000 16M
pmd
0xffffffff81000000-0xffffffff81600000 6M ro PSE GLB
x pmd
0xffffffff81600000-0xffffffff81754000 1360K ro GLB
x pte
0xffffffff81754000-0xffffffff81800000 688K RW GLB
NX pte
0xffffffff81800000-0xffffffff81a00000 2M ro PSE GLB
NX pmd
0xffffffff81a00000-0xffffffff81b3b000 1260K ro GLB
NX pte
0xffffffff81b3b000-0xffffffff82000000 4884K RW GLB
NX pte
0xffffffff82000000-0xffffffff82200000 2M RW PSE GLB
NX pmd
0xffffffff82200000-0xffffffffa0000000 478M
pmd
Signed-off-by: Stephen Smalley <s...@tycho.nsa.gov>
Acked-by: Kees Cook <keesc...@chromium.org>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Mike Galbraith <efa...@gmx.de>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Link:
http://lkml.kernel.org/r/1443704662-3138-1-git-send-email-...@tycho.nsa.gov
Signed-off-by: Ingo Molnar <mi...@kernel.org>
Signed-off-by: Luis Henriques <luis.henriq...@canonical.com>
---
arch/x86/mm/init_64.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 5146f4652092..12e5ac7885f8 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -1131,7 +1131,7 @@ void mark_rodata_ro(void)
* has been zapped already via cleanup_highmem().
*/
all_end = roundup((unsigned long)_brk_end, PMD_SIZE);
- set_memory_nx(rodata_start, (all_end - rodata_start) >> PAGE_SHIFT);
+ set_memory_nx(text_end, (all_end - text_end) >> PAGE_SHIFT);
rodata_test();
--
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