This is a note to let you know that I've just added the patch titled
kernel/kmod.c: check for NULL in call_usermodehelper_exec()
to the 3.4-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:
kernel-kmod.c-check-for-null-in-call_usermodehelper_exec.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 4c1c7be95c345cf2ad537a0c48e9aeadc7304527 Mon Sep 17 00:00:00 2001
From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Date: Mon, 30 Sep 2013 13:45:08 -0700
Subject: kernel/kmod.c: check for NULL in call_usermodehelper_exec()
From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
commit 4c1c7be95c345cf2ad537a0c48e9aeadc7304527 upstream.
If /proc/sys/kernel/core_pattern contains only "|", a NULL pointer
dereference happens upon core dump because argv_split("") returns
argv[0] == NULL.
This bug was once fixed by commit 264b83c07a84 ("usermodehelper: check
subprocess_info->path != NULL") but was by error reintroduced by commit
7f57cfa4e2aa ("usermodehelper: kill the sub_info->path[0] check").
This bug seems to exist since 2.6.19 (the version which core dump to
pipe was added). Depending on kernel version and config, some side
effect might happen immediately after this oops (e.g. kernel panic with
2.6.32-358.18.1.el6).
Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Acked-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/kmod.c | 4 ++++
1 file changed, 4 insertions(+)
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -540,6 +540,10 @@ int call_usermodehelper_exec(struct subp
DECLARE_COMPLETION_ONSTACK(done);
int retval = 0;
+ if (!sub_info->path) {
+ call_usermodehelper_freeinfo(sub_info);
+ return -EINVAL;
+ }
helper_lock();
if (!sub_info->path) {
retval = -EINVAL;
Patches currently in stable-queue which might be from penguin-kernel@xxxxxxxxxxxxxxxxxxx are
queue-3.4/kernel-kmod.c-check-for-null-in-call_usermodehelper_exec.patch
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