[S390] keyboard: integer underflow bug

The "ct" variable should be an unsigned int.  Both struct kbdiacrs
->kb_cnt and struct kbd_data ->accent_table_size are unsigned ints.

Making it signed causes a problem in KBDIACRUC because the user could
set the signed bit and cause a buffer overflow.

Cc: <stable@kernel.org>
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/s390/char/keyboard.c b/drivers/s390/char/keyboard.c
index 8cd58e412b5e..5ad44daef73b 100644
--- a/drivers/s390/char/keyboard.c
+++ b/drivers/s390/char/keyboard.c
@@ -460,7 +460,8 @@ kbd_ioctl(struct kbd_data *kbd, struct file *file,
           unsigned int cmd, unsigned long arg)
 {
         void __user *argp;
-        int ct, perm;
+        unsigned int ct;
+        int perm;
 
         argp = (void __user *)arg;