ax25: uninitialized variable in ax25_setsockopt()

The "opt" variable is unsigned long but we only copy 4 bytes from
the user so the lower 4 bytes are uninitialized.

I have changed the integer overflow checks from ULONG to UINT as well.
This is a slight API change but I don't expect it to break anything.

Fixes: a7b75c5 ("net: pass a sockptr_t into ->setsockopt")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: Dan Carpenter

net/ax25/af_ax25.c

@@ -536,7 +536,7 @@ static int ax25_setsockopt(struct socket *sock, int level, int optname,
 	ax25_cb *ax25;
 	struct net_device *dev;
 	char devname[IFNAMSIZ];
-	unsigned long opt;
+	unsigned int opt;
 	int res = 0;
 
 	if (level != SOL_AX25)
@@ -568,7 +568,7 @@ static int ax25_setsockopt(struct socket *sock, int level, int optname,
 		break;
 
 	case AX25_T1:
-		if (opt < 1 || opt > ULONG_MAX / HZ) {
+		if (opt < 1 || opt > UINT_MAX / HZ) {
 			res = -EINVAL;
 			break;
 		}
@@ -577,7 +577,7 @@ static int ax25_setsockopt(struct socket *sock, int level, int optname,
 		break;
 
 	case AX25_T2:
-		if (opt < 1 || opt > ULONG_MAX / HZ) {
+		if (opt < 1 || opt > UINT_MAX / HZ) {
 			res = -EINVAL;
 			break;
 		}
@@ -593,15 +593,15 @@ static int ax25_setsockopt(struct socket *sock, int level, int optname,
 		break;
 
 	case AX25_T3:
-		if (opt < 1 || opt > ULONG_MAX / HZ) {
+		if (opt < 1 || opt > UINT_MAX / HZ) {
 			res = -EINVAL;
 			break;
 		}
 		ax25->t3 = opt * HZ;
 		break;
 
 	case AX25_IDLE:
-		if (opt > ULONG_MAX / (60 * HZ)) {
+		if (opt > UINT_MAX / (60 * HZ)) {
 			res = -EINVAL;
 			break;
 		}