From: Siwei Zhang <oss@fourdim.xyz> stable inclusion from stable-v6.6.145 commit 83b22d7f7c384564fa42c3cf19bec715c693d7a2 category: bugfix bugzilla: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit 12917f591cea1af36087dba5b9ec888652f0b42a ] hci_abort_conn() read hci_skb_event(hdev->sent_cmd) when a connection was pending, but hdev->sent_cmd can be NULL while req_status is still HCI_REQ_PEND, leading to a NULL pointer dereference and a general protection fault from the hci_rx_work() receive path. Instead of inspecting hdev->sent_cmd, track the in-flight create connection command with a new per-connection HCI_CONN_CREATE flag and route all cancellation through hci_cancel_connect_sync(), which dispatches to a dedicated per-type cancel function. The create command is in exactly one of two states: still queued, or in flight. The cancel function holds cmd_sync_work_lock across the whole decision: the worker takes this lock to dequeue every entry, so while it is held a queued command cannot start running and an in-flight command cannot complete and let the next command become pending. This keeps the flag test and hci_cmd_sync_cancel() atomic with respect to the worker, so a queued command is simply dequeued, and an in-flight command owned by this connection is cancelled without the risk of cancelling an unrelated command that became pending in the meantime. CIS uses the same flag mechanism via HCI_CONN_CREATE_CIS but cannot be dequeued per-connection. hci_acl_create_conn_sync() and hci_le_create_conn_sync() clear HCI_CONN_CREATE after the create command completes, but the command status handler can free conn via hci_conn_del() (for example when the controller rejects the connection) while the worker is still blocked on the connection complete event. Hold a reference on conn across the create command so the flag can be cleared without a use-after-free. Fixes: a13f316e90fd ("Bluetooth: hci_conn: Consolidate code for aborting connections") Cc: stable@vger.kernel.org Suggested-by: XIAO WU <xiaowu.417@qq.com> Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Siwei Zhang <oss@fourdim.xyz> Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Conflicts: net/bluetooth/hci_sync.c [Context differences.] Signed-off-by: Hui Tang <tanghui20@huawei.com> --- include/net/bluetooth/hci_core.h | 1 + net/bluetooth/hci_conn.c | 21 +---- net/bluetooth/hci_sync.c | 133 +++++++++++++++++++++++++++---- 3 files changed, 123 insertions(+), 32 deletions(-) diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h index 22372ddba90d..8da493385bd4 100644 --- a/include/net/bluetooth/hci_core.h +++ b/include/net/bluetooth/hci_core.h @@ -965,6 +965,7 @@ enum { HCI_CONN_AUTH_FAILURE, HCI_CONN_PER_ADV, HCI_CONN_BIG_CREATED, + HCI_CONN_CREATE, HCI_CONN_CREATE_CIS, HCI_CONN_BIG_SYNC, HCI_CONN_BIG_SYNC_FAILED, diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c index 09b03686f913..66199bab8b7d 100644 --- a/net/bluetooth/hci_conn.c +++ b/net/bluetooth/hci_conn.c @@ -2934,26 +2934,11 @@ int hci_abort_conn(struct hci_conn *conn, u8 reason) conn->abort_reason = reason; - /* If the connection is pending check the command opcode since that - * might be blocking on hci_cmd_sync_work while waiting its respective - * event so we need to hci_cmd_sync_cancel to cancel it. - * - * hci_connect_le serializes the connection attempts so only one - * connection can be in BT_CONNECT at time. + /* Cancel the connect attempt. A return of 0 means the create command + * was still queued and got dequeued, so there is nothing to disconnect. */ - if (conn->state == BT_CONNECT && READ_ONCE(hdev->req_status) == HCI_REQ_PEND) { - switch (hci_skb_event(hdev->sent_cmd)) { - case HCI_EV_CONN_COMPLETE: - case HCI_EV_LE_CONN_COMPLETE: - case HCI_EV_LE_ENHANCED_CONN_COMPLETE: - case HCI_EVT_LE_CIS_ESTABLISHED: - hci_cmd_sync_cancel(hdev, ECANCELED); - break; - } - /* Cancel connect attempt if still queued/pending */ - } else if (!hci_cancel_connect_sync(hdev, conn)) { + if (!hci_cancel_connect_sync(hdev, conn)) return 0; - } /* Run immediately if on cmd_sync_work since this may be called * as a result to MGMT_OP_DISCONNECT/MGMT_OP_UNPAIR which does diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c index 1de8e48d1380..90e773cec12f 100644 --- a/net/bluetooth/hci_sync.c +++ b/net/bluetooth/hci_sync.c @@ -6580,6 +6580,11 @@ static int hci_le_create_conn_sync(struct hci_dev *hdev, void *data) bt_dev_dbg(hdev, "conn %p", conn); + /* Hold a reference so conn stays valid for the HCI_CONN_CREATE + * clear_bit() at done. + */ + hci_conn_get(conn); + clear_bit(HCI_CONN_SCANNING, &conn->flags); conn->state = BT_CONNECT; @@ -6592,6 +6597,7 @@ static int hci_le_create_conn_sync(struct hci_dev *hdev, void *data) hdev->le_scan_type == LE_SCAN_ACTIVE && !hci_dev_test_flag(hdev, HCI_LE_SIMULTANEOUS_ROLES)) { hci_conn_del(conn); + hci_conn_put(conn); return -EBUSY; } @@ -6637,6 +6643,12 @@ static int hci_le_create_conn_sync(struct hci_dev *hdev, void *data) &own_addr_type); if (err) goto done; + + /* Mark create connection in flight so hci_cancel_connect_sync() can + * cancel it while blocking on the connection complete event. + */ + set_bit(HCI_CONN_CREATE, &conn->flags); + /* Send command LE Extended Create Connection if supported */ if (use_ext_conn(hdev)) { err = hci_le_ext_create_conn_sync(hdev, conn, own_addr_type); @@ -6672,11 +6684,14 @@ static int hci_le_create_conn_sync(struct hci_dev *hdev, void *data) conn->conn_timeout, NULL); done: + clear_bit(HCI_CONN_CREATE, &conn->flags); + if (err == -ETIMEDOUT) hci_le_connect_cancel_sync(hdev, conn, 0x00); /* Re-enable advertising after the connection attempt is finished. */ hci_resume_advertising_sync(hdev); + hci_conn_put(conn); return err; } @@ -6955,10 +6970,25 @@ static int hci_acl_create_conn_sync(struct hci_dev *hdev, void *data) else cp.role_switch = 0x00; - return __hci_cmd_sync_status_sk(hdev, HCI_OP_CREATE_CONN, - sizeof(cp), &cp, - HCI_EV_CONN_COMPLETE, - conn->conn_timeout, NULL); + /* Hold a reference so conn stays valid for the HCI_CONN_CREATE + * clear_bit() below. + */ + hci_conn_get(conn); + + /* Mark create connection in flight so hci_cancel_connect_sync() can + * cancel it while blocking on the connection complete event. + */ + set_bit(HCI_CONN_CREATE, &conn->flags); + + err = __hci_cmd_sync_status_sk(hdev, HCI_OP_CREATE_CONN, + sizeof(cp), &cp, + HCI_EV_CONN_COMPLETE, + conn->conn_timeout, NULL); + + clear_bit(HCI_CONN_CREATE, &conn->flags); + hci_conn_put(conn); + + return err; } int hci_connect_acl_sync(struct hci_dev *hdev, struct hci_conn *conn) @@ -7010,20 +7040,95 @@ int hci_connect_le_sync(struct hci_dev *hdev, struct hci_conn *conn) return (err == -EEXIST) ? 0 : err; } -int hci_cancel_connect_sync(struct hci_dev *hdev, struct hci_conn *conn) +static int hci_acl_cancel_create_conn_sync(struct hci_dev *hdev, + struct hci_conn *conn) { - if (conn->state != BT_OPEN) - return -EINVAL; + struct hci_cmd_sync_work_entry *entry; + int err = -EBUSY; + + /* cmd_sync_work_lock makes the HCI_CONN_CREATE test and the cancel + * atomic against the worker, which takes this lock to dequeue every + * entry: while it is held no other command can become pending, so + * hci_cmd_sync_cancel() cannot cancel an unrelated command. + */ + mutex_lock(&hdev->cmd_sync_work_lock); + + /* In flight: this connection owns the pending request, cancel it. */ + if (test_bit(HCI_CONN_CREATE, &conn->flags)) { + hci_cmd_sync_cancel(hdev, ECANCELED); + goto unlock; + } + + /* Still queued: a successful dequeue means it never started, so there + * is nothing to disconnect. + */ + entry = _hci_cmd_sync_lookup_entry(hdev, hci_acl_create_conn_sync, conn, + NULL); + if (entry) { + _hci_cmd_sync_cancel_entry(hdev, entry, -ECANCELED); + err = 0; + } + +unlock: + mutex_unlock(&hdev->cmd_sync_work_lock); + return err; +} + +static int hci_le_cancel_create_conn_sync(struct hci_dev *hdev, + struct hci_conn *conn) +{ + struct hci_cmd_sync_work_entry *entry; + int err = -EBUSY; + /* cmd_sync_work_lock keeps the HCI_CONN_CREATE test and the cancel + * atomic against the cmd_sync worker. + */ + mutex_lock(&hdev->cmd_sync_work_lock); + + if (test_bit(HCI_CONN_CREATE, &conn->flags)) { + hci_cmd_sync_cancel(hdev, ECANCELED); + goto unlock; + } + + entry = _hci_cmd_sync_lookup_entry(hdev, hci_le_create_conn_sync, conn, + create_le_conn_complete); + if (entry) { + _hci_cmd_sync_cancel_entry(hdev, entry, -ECANCELED); + err = 0; + } + +unlock: + mutex_unlock(&hdev->cmd_sync_work_lock); + return err; +} + +static int hci_cis_cancel_create_conn_sync(struct hci_dev *hdev, + struct hci_conn *conn) +{ + /* LE Create CIS is shared by the whole CIG and cannot be dequeued + * per-connection, so only an in-flight command can be cancelled. + * cmd_sync_work_lock keeps the test and the cancel atomic against the + * cmd_sync worker. + */ + mutex_lock(&hdev->cmd_sync_work_lock); + + if (test_bit(HCI_CONN_CREATE_CIS, &conn->flags)) + hci_cmd_sync_cancel(hdev, ECANCELED); + + mutex_unlock(&hdev->cmd_sync_work_lock); + return -EBUSY; +} + +int hci_cancel_connect_sync(struct hci_dev *hdev, struct hci_conn *conn) +{ switch (conn->type) { case ACL_LINK: - return !hci_cmd_sync_dequeue_once(hdev, - hci_acl_create_conn_sync, - conn, NULL); + return hci_acl_cancel_create_conn_sync(hdev, conn); case LE_LINK: - return !hci_cmd_sync_dequeue_once(hdev, hci_le_create_conn_sync, - conn, create_le_conn_complete); + return hci_le_cancel_create_conn_sync(hdev, conn); + case CIS_LINK: + return hci_cis_cancel_create_conn_sync(hdev, conn); + default: + return -ENOENT; } - - return -ENOENT; } -- 2.34.1