netrom: avoid overflows in nr_setsockopt()

Check setsockopt arguments to avoid overflows and return -EINVAL for
too large arguments.
Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/netrom/af_netrom.c

@@ -306,26 +306,26 @@ static int nr_setsockopt(struct socket *sock, int level, int optname,
 {
 	struct sock *sk = sock->sk;
 	struct nr_sock *nr = nr_sk(sk);
-	int opt;
+	unsigned long opt;
 
 	if (level != SOL_NETROM)
 		return -ENOPROTOOPT;
 
-	if (optlen < sizeof(int))
+	if (optlen < sizeof(unsigned int))
 		return -EINVAL;
 
-	if (get_user(opt, (int __user *)optval))
+	if (get_user(opt, (unsigned int __user *)optval))
 		return -EFAULT;
 
 	switch (optname) {
 	case NETROM_T1:
-		if (opt < 1)
+		if (opt < 1 || opt > ULONG_MAX / HZ)
 			return -EINVAL;
 		nr->t1 = opt * HZ;
 		return 0;
 
 	case NETROM_T2:
-		if (opt < 1)
+		if (opt < 1 || opt > ULONG_MAX / HZ)
 			return -EINVAL;
 		nr->t2 = opt * HZ;
 		return 0;
@@ -337,13 +337,13 @@ static int nr_setsockopt(struct socket *sock, int level, int optname,
 		return 0;
 
 	case NETROM_T4:
-		if (opt < 1)
+		if (opt < 1 || opt > ULONG_MAX / HZ)
 			return -EINVAL;
 		nr->t4 = opt * HZ;
 		return 0;
 
 	case NETROM_IDLE:
-		if (opt < 0)
+		if (opt > ULONG_MAX / (60 * HZ))
 			return -EINVAL;
 		nr->idle = opt * 60 * HZ;
 		return 0;