From 264b83c07a84223f0efd0d1db9ccc66d6f88288f Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Thu, 16 May 2013 17:43:55 +0200
Subject: [PATCH] usermodehelper: check subprocess_info->path != NULL
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>
---
kernel/kmod.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/kernel/kmod.c b/kernel/kmod.c
index 1296e72e4161..8241906c4b61 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -569,6 +569,11 @@ 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;
--
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