This is a note to let you know that I've just added the patch titled
coredump: fix va_list corruption
to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
coredump-fix-va_list-corruption.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 404ca80eb5c2727d78cd517d12108b040c522e12 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <[email protected]>
Date: Sat, 19 Apr 2014 10:15:07 -0700
Subject: coredump: fix va_list corruption
From: Eric Dumazet <[email protected]>
commit 404ca80eb5c2727d78cd517d12108b040c522e12 upstream.
A va_list needs to be copied in case it needs to be used twice.
Thanks to Hugh for debugging this issue, leading to various panics.
Tested:
lpq84:~# echo "|/foobar12345 %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h
%h %h %h %h" >/proc/sys/kernel/core_pattern
'produce_core' is simply : main() { *(int *)0 = 1;}
lpq84:~# ./produce_core
Segmentation fault (core dumped)
lpq84:~# dmesg | tail -1
[ 614.352947] Core dump to |/foobar12345 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84
lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84
(null) pipe failed
Notice the last argument was replaced by a NULL (we were lucky enough to
not crash, but do not try this on your production machine !)
After fix :
lpq83:~# echo "|/foobar12345 %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h
%h %h %h %h" >/proc/sys/kernel/core_pattern
lpq83:~# ./produce_core
Segmentation fault
lpq83:~# dmesg | tail -1
[ 740.800441] Core dump to |/foobar12345 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83
lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83
lpq83 pipe failed
Fixes: 5fe9d8ca21cc ("coredump: cn_vprintf() has no reason to call vsnprintf()
twice")
Signed-off-by: Eric Dumazet <[email protected]>
Diagnosed-by: Hugh Dickins <[email protected]>
Acked-by: Oleg Nesterov <[email protected]>
Cc: Neil Horman <[email protected]>
Cc: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
fs/coredump.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -73,10 +73,15 @@ static int expand_corename(struct core_n
static int cn_vprintf(struct core_name *cn, const char *fmt, va_list arg)
{
int free, need;
+ va_list arg_copy;
again:
free = cn->size - cn->used;
- need = vsnprintf(cn->corename + cn->used, free, fmt, arg);
+
+ va_copy(arg_copy, arg);
+ need = vsnprintf(cn->corename + cn->used, free, fmt, arg_copy);
+ va_end(arg_copy);
+
if (need < free) {
cn->used += need;
return 0;
Patches currently in stable-queue which might be from [email protected] are
queue-3.14/coredump-fix-va_list-corruption.patch
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