From be639ac6901a082894771f55c8047d5772de5c27 Mon Sep 17 00:00:00 2001
From: Ralf Baechle <ralf@linux-mips.org>
Date: Thu, 24 Nov 2011 06:12:59 +0000
Subject: NET: AX.25: Check ioctl arguments to avoid overflows further down the
 road.

Very large, nonsenical arguments or use in very extreme conditions could
result in integer overflows.  Check ioctls arguments to avoid such
overflows and return -EINVAL for too large arguments.

To allow the use of AX.25 for even the most extreme setup (think packet
radio to the Phase 5E mars probe) we make no further attempt to clamp the
argument range.

Originally reported by Fan Long <longfancn@gmail.com> and a first patch
was sent by Xi Wang <xi.wang@gmail.com>.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Xi Wang <xi.wang@gmail.com>
Cc: Joerg Reuter <jreuter@yaina.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Thomas Osterried <thomas@osterried.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ax25/af_ax25.c b/net/ax25/af_ax25.c
index e7c69f4..b863c18 100644
--- a/net/ax25/af_ax25.c
+++ b/net/ax25/af_ax25.c
@@ -402,14 +402,14 @@ static int ax25_ctl_ioctl(const unsigned int cmd, void __user *arg)
 		break;
 
 	case AX25_T1:
-		if (ax25_ctl.arg < 1)
+		if (ax25_ctl.arg < 1 || ax25_ctl.arg > ULONG_MAX / HZ)
 			goto einval_put;
 		ax25->rtt = (ax25_ctl.arg * HZ) / 2;
 		ax25->t1  = ax25_ctl.arg * HZ;
 		break;
 
 	case AX25_T2:
-		if (ax25_ctl.arg < 1)
+		if (ax25_ctl.arg < 1 || ax25_ctl.arg > ULONG_MAX / HZ)
 			goto einval_put;
 		ax25->t2 = ax25_ctl.arg * HZ;
 		break;
@@ -422,10 +422,15 @@ static int ax25_ctl_ioctl(const unsigned int cmd, void __user *arg)
 		break;
 
 	case AX25_T3:
+		if (ax25_ctl.arg > ULONG_MAX / HZ)
+			goto einval_put;
 		ax25->t3 = ax25_ctl.arg * HZ;
 		break;
 
 	case AX25_IDLE:
+		if (ax25_ctl.arg > ULONG_MAX / (60 * HZ))
+			goto einval_put;
+
 		ax25->idle = ax25_ctl.arg * 60 * HZ;
 		break;
 
@@ -571,7 +576,7 @@ static int ax25_setsockopt(struct socket *sock, int level, int optname,
 		break;
 
 	case AX25_T1:
-		if (opt < 1) {
+		if (opt < 1 || opt > ULONG_MAX / HZ) {
 			res = -EINVAL;
 			break;
 		}
@@ -580,7 +585,7 @@ static int ax25_setsockopt(struct socket *sock, int level, int optname,
 		break;
 
 	case AX25_T2:
-		if (opt < 1) {
+		if (opt < 1 || opt > ULONG_MAX / HZ) {
 			res = -EINVAL;
 			break;
 		}
@@ -596,7 +601,7 @@ static int ax25_setsockopt(struct socket *sock, int level, int optname,
 		break;
 
 	case AX25_T3:
-		if (opt < 1) {
+		if (opt < 1 || opt > ULONG_MAX / HZ) {
 			res = -EINVAL;
 			break;
 		}
@@ -604,7 +609,7 @@ static int ax25_setsockopt(struct socket *sock, int level, int optname,
 		break;
 
 	case AX25_IDLE:
-		if (opt < 0) {
+		if (opt < 0 || opt > ULONG_MAX / (60 * HZ)) {
 			res = -EINVAL;
 			break;
 		}
-- 
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