Bluetooth: Check the minimum {I,S}-frame size into L2CAP

All packets with size fewer than the minimum specified is dropped.
Note that the size of the l2cap basic header, FCS and SAR fields are
already subtracted of len at the moment of the size check.

Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
Reviewed-by: João Paulo Rechi Vita <jprvita@profusion.mobi>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index 36cd4e4e6ad1923dd5082eb46073563dcd63afc8..ac00f5fac2d2649f1c773c03f9d94e51fdeae836 100644 (file)
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -3627,10 +3627,17 @@ static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk
                if (l2cap_check_fcs(pi, skb))
                        goto drop;
 
-               if (__is_iframe(control))
+               if (__is_iframe(control)) {
+                       if (len < 4)
+                               goto drop;
+
                        l2cap_data_channel_iframe(sk, control, skb);
-               else
+               } else {
+                       if (len != 0)
+                               goto drop;
+
                        l2cap_data_channel_sframe(sk, control, skb);
+               }
 
                goto done;
 
@@ -3645,7 +3652,8 @@ static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk
                if (pi->fcs == L2CAP_FCS_CRC16)
                        len -= 2;
 
-               if (len > L2CAP_DEFAULT_MAX_PDU_SIZE || __is_sframe(control))
+               if (len > L2CAP_DEFAULT_MAX_PDU_SIZE || len < 4
+                               || __is_sframe(control))
                        goto drop;
 
                if (l2cap_check_fcs(pi, skb))