From: Luiz Augusto von Dentz Date: Tue, 3 Mar 2026 18:29:53 +0000 (-0500) Subject: Bluetooth: L2CAP: Fix accepting multiple L2CAP_ECRED_CONN_REQ X-Git-Tag: v7.0-rc5~31^2~32^2~3 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=5b3e2052334f2ff6d5200e952f4aa66994d09899;p=thirdparty%2Fkernel%2Fstable.git Bluetooth: L2CAP: Fix accepting multiple L2CAP_ECRED_CONN_REQ Currently the code attempts to accept requests regardless of the command identifier which may cause multiple requests to be marked as pending (FLAG_DEFER_SETUP) which can cause more than L2CAP_ECRED_MAX_CID(5) to be allocated in l2cap_ecred_rsp_defer causing an overflow. The spec is quite clear that the same identifier shall not be used on subsequent requests: 'Within each signaling channel a different Identifier shall be used for each successive request or indication.' https://www.bluetooth.com/wp-content/uploads/Files/Specification/HTML/Core-62/out/en/host/logical-link-control-and-adaptation-protocol-specification.html#UUID-32a25a06-4aa4-c6c7-77c5-dcfe3682355d So this attempts to check if there are any channels pending with the same identifier and rejects if any are found. Fixes: 15f02b910562 ("Bluetooth: L2CAP: Add initial code for Enhanced Credit Based Mode") Reported-by: Yiming Qian Signed-off-by: Luiz Augusto von Dentz --- diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c index 780136e18aae5..9d5b8d4d375a5 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -5055,7 +5055,7 @@ static inline int l2cap_ecred_conn_req(struct l2cap_conn *conn, u16 mtu, mps; __le16 psm; u8 result, rsp_len = 0; - int i, num_scid; + int i, num_scid = 0; bool defer = false; if (!enable_ecred) @@ -5068,6 +5068,14 @@ static inline int l2cap_ecred_conn_req(struct l2cap_conn *conn, goto response; } + /* Check if there are no pending channels with the same ident */ + __l2cap_chan_list_id(conn, cmd->ident, l2cap_ecred_list_defer, + &num_scid); + if (num_scid) { + result = L2CAP_CR_LE_INVALID_PARAMS; + goto response; + } + cmd_len -= sizeof(*req); num_scid = cmd_len / sizeof(u16);