Subject: + kernel-kmodc-check-for-null-in-call_usermodehelper_exec.patch added to -mm tree
To: penguin-kernel@xxxxxxxxxxxxxxxxxxx,oleg@xxxxxxxxxx,stable@xxxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Mon, 23 Sep 2013 14:29:15 -0700
The patch titled
Subject: kernel/kmod.c: check for NULL in call_usermodehelper_exec()
has been added to the -mm tree. Its filename is
kernel-kmodc-check-for-null-in-call_usermodehelper_exec.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/kernel-kmodc-check-for-null-in-call_usermodehelper_exec.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/kernel-kmodc-check-for-null-in-call_usermodehelper_exec.patch
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The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Subject: kernel/kmod.c: check for NULL in call_usermodehelper_exec()
If /proc/sys/kernel/core_pattern contains only "|", NULL pointer
dereference happens upon core dump because argv_split("") returns argv[0]
== NULL.
This bug was once fixed by commit 264b83c0 ("usermodehelper: check
subprocess_info->path != NULL") but was by error reintroduced by commit
7f57cfa4 ("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>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/kmod.c | 4 ++++
1 file changed, 4 insertions(+)
diff -puN kernel/kmod.c~kernel-kmodc-check-for-null-in-call_usermodehelper_exec kernel/kmod.c
--- a/kernel/kmod.c~kernel-kmodc-check-for-null-in-call_usermodehelper_exec
+++ a/kernel/kmod.c
@@ -571,6 +571,10 @@ int call_usermodehelper_exec(struct subp
DECLARE_COMPLETION_ONSTACK(done);
int retval = 0;
+ if (!sub_info->path) {
+ call_usermodehelper_freeinfo(sub_info);
+ return -ENOENT;
+ }
helper_lock();
if (!khelper_wq || usermodehelper_disabled) {
retval = -EBUSY;
_
Patches currently in -mm which might be from penguin-kernel@xxxxxxxxxxxxxxxxxxx are
kernel-kmodc-check-for-null-in-call_usermodehelper_exec.patch
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