tree 509dd304b80cf3d53f03c03fcbbc99d05fec7924
parent 5c64e3a45d43c6e3fa87cbe02e10059171d10812
author Oleg Nesterov <oleg@redhat.com> 1368719035 +0200
committer Linus Torvalds <torvalds@linux-foundation.org> 1368730871 -0700

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>