From: Cen Zhang Date: Tue, 7 Jul 2026 04:15:18 +0000 (+0800) Subject: Bluetooth: MGMT: revalidate LOAD_CONN_PARAM queued update X-Git-Tag: v7.2-rc4~17^2~10^2~7 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2bf282f8f715f5d05d6f4c49ffb3bd241c5e667e;p=thirdparty%2Fkernel%2Flinux.git Bluetooth: MGMT: revalidate LOAD_CONN_PARAM queued update MGMT_OP_LOAD_CONN_PARAM queues conn_update_sync() when a single parameter update changes an existing LE central connection. The queued work currently stores a borrowed hci_conn_params entry from hdev->le_conn_params. A later LOAD_CONN_PARAM request can clear disabled parameters and free that entry before hci_cmd_sync_work() runs the queued callback. Do not keep the borrowed hci_conn_params pointer in queued work. Queue the hci_conn instead and hold a reference until the queued callback completes. When the work runs, revalidate that the connection is still present, look up the current hci_conn_params entry, and cancel the update if userspace removed that entry while the work was pending. Copy the interval values from the current params entry under hdev->lock, then drop the lock and keep using hci_le_conn_update_sync() to issue the update. Validation reproduced this kernel report: BUG: KASAN: slab-use-after-free in conn_update_sync+0x2a/0xf0 [bluetooth] Read of size 1 at addr ffff88810c697126 by task kworker/u17:0/377 Workqueue: hci0 hci_cmd_sync_work [bluetooth] Call Trace: dump_stack_lvl+0x66/0xa0 print_report+0xce/0x5f0 kasan_report+0xe0/0x110 conn_update_sync+0x2a/0xf0 [bluetooth] hci_cmd_sync_work+0x187/0x210 [bluetooth] process_one_work+0x4fd/0xbc0 worker_thread+0x2d8/0x570 kthread+0x1ad/0x1f0 ret_from_fork+0x3c9/0x540 ret_from_fork_asm+0x1a/0x30 Allocated by task 466: hci_conn_params_add+0xa6/0x240 [bluetooth] load_conn_param+0x4e1/0x850 [bluetooth] hci_sock_sendmsg+0x96b/0xf80 [bluetooth] Freed by task 474: kfree+0x313/0x590 hci_conn_params_clear_disabled+0x9b/0xc0 [bluetooth] load_conn_param+0x4bf/0x850 [bluetooth] hci_sock_sendmsg+0x96b/0xf80 [bluetooth] Fixes: 0ece498c27d8c ("Bluetooth: MGMT: Make MGMT_OP_LOAD_CONN_PARAM update existing connection") Suggested-by: Luiz Augusto von Dentz Assisted-by: Codex:gpt-5.5 Signed-off-by: Cen Zhang Signed-off-by: Luiz Augusto von Dentz --- diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c index 733a4b70e10c..a0a491e5311e 100644 --- a/net/bluetooth/mgmt.c +++ b/net/bluetooth/mgmt.c @@ -7937,14 +7937,36 @@ unlock: static int conn_update_sync(struct hci_dev *hdev, void *data) { - struct hci_conn_params *params = data; - struct hci_conn *conn; + struct hci_conn *conn = data; + struct hci_conn_params *params; + struct hci_conn_params local = {}; - conn = hci_conn_hash_lookup_le(hdev, ¶ms->addr, params->addr_type); - if (!conn) - return -ECANCELED; + hci_dev_lock(hdev); + + if (!hci_conn_valid(hdev, conn) || conn->role != HCI_ROLE_MASTER) + goto cancel; + + params = hci_conn_params_lookup(hdev, &conn->dst, conn->dst_type); + if (!params) + goto cancel; + + local.conn_min_interval = params->conn_min_interval; + local.conn_max_interval = params->conn_max_interval; + local.conn_latency = params->conn_latency; + local.supervision_timeout = params->supervision_timeout; - return hci_le_conn_update_sync(hdev, conn, params); + hci_dev_unlock(hdev); + + return hci_le_conn_update_sync(hdev, conn, &local); + +cancel: + hci_dev_unlock(hdev); + return -ECANCELED; +} + +static void conn_update_sync_destroy(struct hci_dev *hdev, void *data, int err) +{ + hci_conn_put(data); } static int load_conn_param(struct sock *sk, struct hci_dev *hdev, void *data, @@ -8054,9 +8076,13 @@ static int load_conn_param(struct sock *sk, struct hci_dev *hdev, void *data, (conn->le_conn_min_interval != min || conn->le_conn_max_interval != max || conn->le_conn_latency != latency || - conn->le_supv_timeout != timeout)) - hci_cmd_sync_queue(hdev, conn_update_sync, - hci_param, NULL); + conn->le_supv_timeout != timeout)) { + hci_conn_get(conn); + if (hci_cmd_sync_queue(hdev, conn_update_sync, + conn, + conn_update_sync_destroy) < 0) + hci_conn_put(conn); + } } }