Bluetooth: Only check SAR bits if frame is an I-frame

The SAR bits doesn't make sense for an S-frame. It doesn't use SAR.

Checking SAR for a S-frames can lead to L2CAP errors, it could close
the channel with an invalid packet length, since we was removing the 2
of the of any frame that match SAR start bits, without check if it is
an I-frame.

Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index a9fdfe401f5b..108c2f290ac5 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -4117,7 +4117,7 @@ static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk
                 skb_pull(skb, 2);
                 len = skb->len;
 
-                if (__is_sar_start(control))
+                if (__is_sar_start(control) && __is_iframe(control))
                         len -= 2;
 
                 if (pi->fcs == L2CAP_FCS_CRC16)