commit be639ac6901a082894771f55c8047d5772de5c27
author Ralf Baechle <ralf@linux-mips.org> Thu Nov 24 06:12:59 2011 +0000
committer David S. Miller <davem@davemloft.net> Tue Nov 29 00:23:12 2011 -0500
tree 3c2b8e72ba8f5625d338c2104f936eef41b79175
parent 3b1588593097b7d71f44c4b7b435bf28924316e0

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>

net/ax25/af_ax25.c

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 @@
 		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 @@
 		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 @@
 		break;
 
 	case AX25_T1:
-		if (opt < 1) {
+		if (opt < 1 || opt > ULONG_MAX / HZ) {
 			res = -EINVAL;
 			break;
 		}
@@ -580,7 +585,7 @@
 		break;
 
 	case AX25_T2:
-		if (opt < 1) {
+		if (opt < 1 || opt > ULONG_MAX / HZ) {
 			res = -EINVAL;
 			break;
 		}
@@ -596,7 +601,7 @@
 		break;
 
 	case AX25_T3:
-		if (opt < 1) {
+		if (opt < 1 || opt > ULONG_MAX / HZ) {
 			res = -EINVAL;
 			break;
 		}
@@ -604,7 +609,7 @@
 		break;
 
 	case AX25_IDLE:
-		if (opt < 0) {
+		if (opt < 0 || opt > ULONG_MAX / (60 * HZ)) {
 			res = -EINVAL;
 			break;
 		}