[55/65] usermodehelper: check subprocess_info->path != NULL

Steven Rostedt
2013-06-03T22:15:29Z

[-- Attachment #1: 0055-usermodehelper-check-subprocess_info-path-NULL.patch --]
[-- Type: text/plain, Size: 1256 bytes --]

3.6.11.5 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Oleg Nesterov <oleg@redhat.com>

[ Upstream commit 264b83c07a84223f0efd0d1db9ccc66d6f88288f ]

argv_split(empty_or_all_spaces) happily succeeds, it simply returns
argc == 0 and argv[0] == NULL. Change call_usermodehelper_exec() to
check sub_info->path != NULL to avoid the crash.

This is the minimal fix, todo:

- perhaps we should change argv_split() to return NULL or change the
callers.

- kill or justify ->path[0] check

- narrow the scope of helper_lock()

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-By: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/kmod.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/kernel/kmod.c b/kernel/kmod.c
index 6f99aea..122a299 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -558,6 +558,11 @@ int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait)
int retval = 0;

helper_lock();
+ if (!sub_info->path) {
+ retval = -EINVAL;
+ goto out;
+ }
+
if (sub_info->path[0] == '\0')
goto out;

--
1.7.10.4