netrom: fix api breakage in nr_setsockopt()

[ Upstream commit dc35616e6c ]

This needs to copy an unsigned int from user space instead of a long to
avoid breaking user space with an API change.

I have updated all the integer overflow checks from ULONG to UINT as
well.  This is a slight API change but I do not expect it to affect
anything in real life.

Fixes: 3087a6f36e ("netrom: fix copying in user data in nr_setsockopt")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

net/netrom/af_netrom.c

@@ -298,7 +298,7 @@ static int nr_setsockopt(struct socket *sock, int level, int optname,
 {
 	struct sock *sk = sock->sk;
 	struct nr_sock *nr = nr_sk(sk);
-	unsigned long opt;
+	unsigned int opt;
 
 	if (level != SOL_NETROM)
 		return -ENOPROTOOPT;
@@ -306,18 +306,18 @@ static int nr_setsockopt(struct socket *sock, int level, int optname,
 	if (optlen < sizeof(unsigned int))
 		return -EINVAL;
 
-	if (copy_from_sockptr(&opt, optval, sizeof(unsigned long)))
+	if (copy_from_sockptr(&opt, optval, sizeof(opt)))
 		return -EFAULT;
 
 	switch (optname) {
 	case NETROM_T1:
-		if (opt < 1 || opt > ULONG_MAX / HZ)
+		if (opt < 1 || opt > UINT_MAX / HZ)
 			return -EINVAL;
 		nr->t1 = opt * HZ;
 		return 0;
 
 	case NETROM_T2:
-		if (opt < 1 || opt > ULONG_MAX / HZ)
+		if (opt < 1 || opt > UINT_MAX / HZ)
 			return -EINVAL;
 		nr->t2 = opt * HZ;
 		return 0;
@@ -329,13 +329,13 @@ static int nr_setsockopt(struct socket *sock, int level, int optname,
 		return 0;
 
 	case NETROM_T4:
-		if (opt < 1 || opt > ULONG_MAX / HZ)
+		if (opt < 1 || opt > UINT_MAX / HZ)
 			return -EINVAL;
 		nr->t4 = opt * HZ;
 		return 0;
 
 	case NETROM_IDLE:
-		if (opt > ULONG_MAX / (60 * HZ))
+		if (opt > UINT_MAX / (60 * HZ))
 			return -EINVAL;
 		nr->idle = opt * 60 * HZ;
 		return 0;