Bluetooth: L2CAP: Add missing checks for invalid DCID

[ Upstream commit 75767213f3d9b97f63694d02260b6a49a2271876 ]

When receiving a connect response we should make sure that the DCID is
within the valid range and that we don't already have another channel
allocated for the same DCID.
Missing checks may violate the specification (BLUETOOTH CORE SPECIFICATION
Version 5.4 | Vol 3, Part A, Page 1046).

Fixes: 40624183c202 ("Bluetooth: L2CAP: Add missing checks for invalid LE DCID")
Signed-off-by: Sungwoo Kim <iam@sung-woo.kim>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index d91ddcd54e278b94734c9b374e305c31c0f9aab6..fcc471f9218951394e902f165f2ce0c4be6402e0 100644 (file)
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -4007,6 +4007,10 @@ static int l2cap_connect_create_rsp(struct l2cap_conn *conn,
        result = __le16_to_cpu(rsp->result);
        status = __le16_to_cpu(rsp->status);
 
+       if (result == L2CAP_CR_SUCCESS && (dcid < L2CAP_CID_DYN_START ||
+                                          dcid > L2CAP_CID_DYN_END))
+               return -EPROTO;
+
        BT_DBG("dcid 0x%4.4x scid 0x%4.4x result 0x%2.2x status 0x%2.2x",
               dcid, scid, result, status);
 
@@ -4038,6 +4042,11 @@ static int l2cap_connect_create_rsp(struct l2cap_conn *conn,
 
        switch (result) {
        case L2CAP_CR_SUCCESS:
+               if (__l2cap_get_chan_by_dcid(conn, dcid)) {
+                       err = -EBADSLT;
+                       break;
+               }
+
                l2cap_state_change(chan, BT_CONFIG);
                chan->ident = 0;
                chan->dcid = dcid;