fault-injection: set bounds on what /proc/self/make-it-fail accepts.

/proc/self/make-it-fail is a boolean, but accepts any number, including
negative ones.  Change variable to unsigned, and cap upper bound at 1.

[akpm@linux-foundation.org: don't make make_it_fail unsigned]
Signed-off-by: Dave Jones <davej@fedoraproject.org>
Reviewed-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 8da60e768b42..6b7087e2e8fb 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1236,6 +1236,9 @@ static ssize_t proc_fault_inject_write(struct file * file,
         make_it_fail = simple_strtol(strstrip(buffer), &end, 0);
         if (*end)
                 return -EINVAL;
+        if (make_it_fail < 0 || make_it_fail > 1)
+                return -EINVAL;
+
         task = get_proc_task(file_inode(file));
         if (!task)
                 return -ESRCH;