[PATCH] Bluetooth: fix oob in rfcomm_sock_setsockopt

[Edward Adam Davis]

If optlen < sizeof(u32) it will trigger oob, so take the min of them.

Reported-by: syzbot+d4ecae01a53fd9b42e7d@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Edward Adam Davis <eadavis@xxxxxx>
---
 net/bluetooth/rfcomm/sock.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c
index b54e8a530f55..42c55c756b51 100644
--- a/net/bluetooth/rfcomm/sock.c
+++ b/net/bluetooth/rfcomm/sock.c
@@ -629,7 +629,7 @@ static int rfcomm_sock_setsockopt_old(struct socket *sock, int optname,
 
 	switch (optname) {
 	case RFCOMM_LM:
-		if (copy_from_sockptr(&opt, optval, sizeof(u32))) {
+		if (copy_from_sockptr(&opt, optval, min_t(int, sizeof(u32), optlen))) {
 			err = -EFAULT;
 			break;
 		}
-- 
2.43.0