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-3.19.y-queue branch of the 3.19.y-ckt extended stable tree
which can be found at:
http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue
This patch is scheduled to be released in version 3.19.8-ckt10.
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Kamal
------
>From 29d614489d3e62515ee220533e102bafff2068cc Mon Sep 17 00:00:00 2001
From: Stephen Smalley <[email protected]>
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 <[email protected]>
Acked-by: Kees Cook <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Link:
http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Kamal Mostafa <[email protected]>
---
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 30eb05a..9d6e27eb 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -1146,7 +1146,7 @@ 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();
--
1.9.1
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