[PATCH] [174/275] keyboard: integer underflow bug

[Andi Kleen]

2.6.35-longterm review patch.  If anyone has any objections, please let me know.

------------------
From: Dan Carpenter <error27@xxxxxxxxx>

commit b652277b09d3d030cb074cc6a98ba80b34244c03 upstream.

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.

Signed-off-by: Dan Carpenter <error27@xxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>

---
 drivers/s390/char/keyboard.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Index: linux-2.6.35.y/drivers/s390/char/keyboard.c
===================================================================
--- linux-2.6.35.y.orig/drivers/s390/char/keyboard.c	2011-03-29 22:50:54.267869839 -0700
+++ linux-2.6.35.y/drivers/s390/char/keyboard.c	2011-03-29 23:03:01.863252494 -0700
@@ -460,7 +460,8 @@
 	  unsigned int cmd, unsigned long arg)
 {
 	void __user *argp;
-	int ct, perm;
+	unsigned int ct;
+	int perm;
 
 	argp = (void __user *)arg;
 
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