[PATCH] Set bounds on what /proc/self/make-it-fail accepts.

[Dave Jones <davej@redhat.com>]

/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.

Signed-off-by: Dave Jones <davej@fedoraproject.org>

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 51507065263b..b926377c354f 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1207,7 +1207,7 @@ static ssize_t proc_fault_inject_read(struct file * file, char __user * buf,
 	struct task_struct *task = get_proc_task(file_inode(file));
 	char buffer[PROC_NUMBUF];
 	size_t len;
-	int make_it_fail;
+	unsigned int make_it_fail;
 
 	if (!task)
 		return -ESRCH;
@@ -1224,7 +1224,7 @@ static ssize_t proc_fault_inject_write(struct file * file,
 {
 	struct task_struct *task;
 	char buffer[PROC_NUMBUF], *end;
-	int make_it_fail;
+	unsigned int make_it_fail;
 
 	if (!capable(CAP_SYS_RESOURCE))
 		return -EPERM;
@@ -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 > 1)
+		return -EINVAL;
+
 	task = get_proc_task(file_inode(file));
 	if (!task)
 		return -ESRCH;