diff options
| author | Luiz Augusto von Dentz <luiz.von.dentz@intel.com> | 2026-05-11 12:09:42 -0400 |
|---|---|---|
| committer | Luiz Augusto von Dentz <luiz.von.dentz@intel.com> | 2026-05-27 15:29:16 -0400 |
| commit | 1403053c428f6ef054b0bfb0f62d0cb578f93b4d (patch) | |
| tree | 89d8293b4185bc71528334a4a992a3779da70077 /net | |
| parent | 4fe5ea11ac728b12b5a139742ed9f561ccd2707e (diff) | |
| download | linux-next-history-1403053c428f6ef054b0bfb0f62d0cb578f93b4d.tar.gz | |
Bluetooth: L2CAP: Fix possible crash on l2cap_ecred_conn_rsp
If dcid is received for an already-assigned destination CID the spec
requires that both channels to be discarded, but calling l2cap_chan_del
may invalidate the tmp cursor created by list_for_each_entry_safe and
in fact it is the wrong procedure as the chan->dcid may be assigned
previously it really needs to be disconnected.
Calling l2cap_chan_clone directly may still lead to l2cap_chan_del so
instead schedule l2cap_chan_timeout with delay 0 to close the channel
asynchronously.
Fixes: 15f02b910562 ("Bluetooth: L2CAP: Add initial code for Enhanced Credit Based Mode")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Diffstat (limited to 'net')
| -rw-r--r-- | net/bluetooth/l2cap_core.c | 27 |
1 files changed, 22 insertions, 5 deletions
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c index ff13c43e3588c..45b175399e8db 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -5262,6 +5262,7 @@ static inline int l2cap_ecred_conn_rsp(struct l2cap_conn *conn, cmd_len -= sizeof(*rsp); list_for_each_entry_safe(chan, tmp, &conn->chan_l, list) { + struct l2cap_chan *orig; u16 dcid; if (chan->ident != cmd->ident || @@ -5283,8 +5284,10 @@ static inline int l2cap_ecred_conn_rsp(struct l2cap_conn *conn, BT_DBG("dcid[%d] 0x%4.4x", i, dcid); + orig = __l2cap_get_chan_by_dcid(conn, dcid); + /* Check if dcid is already in use */ - if (dcid && __l2cap_get_chan_by_dcid(conn, dcid)) { + if (dcid && orig) { /* If a device receives a * L2CAP_CREDIT_BASED_CONNECTION_RSP packet with an * already-assigned Destination CID, then both the @@ -5293,10 +5296,24 @@ static inline int l2cap_ecred_conn_rsp(struct l2cap_conn *conn, */ l2cap_chan_del(chan, ECONNREFUSED); l2cap_chan_unlock(chan); - chan = __l2cap_get_chan_by_dcid(conn, dcid); - l2cap_chan_lock(chan); - l2cap_chan_del(chan, ECONNRESET); - l2cap_chan_unlock(chan); + + /* Check that the dcid channel mode is + * L2CAP_MODE_EXT_FLOWCTL since this procedure is only + * valid for that mode and shouldn't disconnect a dcid + * in other modes. + */ + if (orig->mode == L2CAP_MODE_EXT_FLOWCTL) { + l2cap_chan_lock(orig); + /* Disconnect the original channel as it may be + * considered connected since dcid has already + * been assigned; don't call l2cap_chan_close + * directly since that could lead to + * l2cap_chan_del and then removing the channel + * from the list while we're iterating over it. + */ + __set_chan_timer(orig, 0); + l2cap_chan_unlock(orig); + } continue; } |