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Fri, 07 Aug 2026 03:15:39 -0700 (PDT) From: Baul Lee To: Luiz Augusto von Dentz , Marcel Holtmann , Brian Gix Cc: Baul Lee , Luiz Augusto von Dentz , Dmitry Antipov , linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org, federico.kirschbaum@xbow.com, stable@vger.kernel.org Subject: [PATCH v2 1/3] Bluetooth: MGMT: remove the mesh walk from the socket destructor Date: Fri, 7 Aug 2026 19:15:27 +0900 Message-ID: <20260807101529.17348-2-baul.lee@xbow.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20260807101529.17348-1-baul.lee@xbow.com> References: <20260807101529.17348-1-baul.lee@xbow.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" hci_sock_destruct() calls mgmt_cleanup(), which walks hdev->mesh_pending on every registered controller looking for entries owned by the socket being destroyed, and completes the ones it finds. It can never find one. mgmt_mesh_add() takes a reference on the owning socket for every entry it links onto the list and mgmt_mesh_remove() drops it again, so the socket's reference count cannot reach zero while one of its entries is there. The walk still races the list. mgmt_mesh_next() loads mesh_tx->sk from every node it passes, including nodes owned by other sockets, while the cmd_sync worker unlinks and frees nodes of the same list under a different lock. mgmt_cleanup() cannot take hdev->lock: it holds read_lock(&hci_dev_list_lock) across the walk, and hdev->lock sleeps. It is the one user of hdev->mesh_pending that cannot be brought under that lock. Remove mgmt_cleanup() and its caller. Discovered by XBOW, triaged by Baul Lee Fixes: b338d91703fa ("Bluetooth: Implement support for Mesh") Cc: stable@vger.kernel.org Signed-off-by: Baul Lee --- include/net/bluetooth/bluetooth.h | 1 - net/bluetooth/hci_sock.c | 1 - net/bluetooth/mgmt.c | 19 ------------------- 3 files changed, 21 deletions(-) diff --git a/include/net/bluetooth/bluetooth.h b/include/net/bluetooth/blue= tooth.h index b624da5026f5..f49cec5f01e6 100644 --- a/include/net/bluetooth/bluetooth.h +++ b/include/net/bluetooth/bluetooth.h @@ -675,7 +675,6 @@ static inline bool iso_inited(void) =20 int mgmt_init(void); void mgmt_exit(void); -void mgmt_cleanup(struct sock *sk); =20 void bt_sock_reclassify_lock(struct sock *sk, int proto); =20 diff --git a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c index 070ca388f9ac..5073f4fc3289 100644 --- a/net/bluetooth/hci_sock.c +++ b/net/bluetooth/hci_sock.c @@ -2164,7 +2164,6 @@ static int hci_sock_getsockopt(struct socket *sock, i= nt level, int optname, =20 static void hci_sock_destruct(struct sock *sk) { - mgmt_cleanup(sk); skb_queue_purge(&sk->sk_receive_queue); skb_queue_purge(&sk->sk_write_queue); skb_queue_purge(&sk->sk_error_queue); diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c index 860c086011b7..97408904f74b 100644 --- a/net/bluetooth/mgmt.c +++ b/net/bluetooth/mgmt.c @@ -10894,22 +10894,3 @@ void mgmt_exit(void) { hci_mgmt_chan_unregister(&chan); } - -void mgmt_cleanup(struct sock *sk) -{ - struct mgmt_mesh_tx *mesh_tx; - struct hci_dev *hdev; - - read_lock(&hci_dev_list_lock); - - list_for_each_entry(hdev, &hci_dev_list, list) { - do { - mesh_tx =3D mgmt_mesh_next(hdev, sk); - - if (mesh_tx) - mesh_send_complete(hdev, mesh_tx, true); - } while (mesh_tx); - } - - read_unlock(&hci_dev_list_lock); -} --=20 2.50.1 (Apple Git-155) From nobody Tue Sep 29 13:19:14 2026 Received: from mail-pj1-f43.google.com (mail-pj1-f43.google.com [209.85.216.43]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 581A046D2B7 for ; 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Fri, 07 Aug 2026 03:15:43 -0700 (PDT) Received: from localhost.localdomain ([1.220.41.130]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-39085dea04bsm4399162a91.8.2026.08.07.03.15.40 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Fri, 07 Aug 2026 03:15:43 -0700 (PDT) From: Baul Lee To: Luiz Augusto von Dentz , Marcel Holtmann , Brian Gix Cc: Baul Lee , Luiz Augusto von Dentz , Dmitry Antipov , linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org, federico.kirschbaum@xbow.com, stable@vger.kernel.org Subject: [PATCH v2 2/3] Bluetooth: MGMT: protect hdev->mesh_pending with hdev->lock Date: Fri, 7 Aug 2026 19:15:28 +0900 Message-ID: <20260807101529.17348-3-baul.lee@xbow.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20260807101529.17348-1-baul.lee@xbow.com> References: <20260807101529.17348-1-baul.lee@xbow.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" hdev->mesh_pending carries the queued struct mgmt_mesh_tx of the mesh mgmt interface. It is extended and walked from syscall context under hci_dev_lock(hdev), in mgmt_mesh_add() and mgmt_mesh_foreach(), and it is unlinked and freed from the hci_cmd_sync worker under hci_req_sync_lock(hdev), in send_cancel(), mesh_send_done_sync() and mesh_next(). The two sides hold different mutexes, so the list has no protection: MGMT_OP_MESH_READ_FEATURES on one socket can be mid-walk while MGMT_OP_MESH_SEND_CANCEL on another frees the entry it is standing on. [ 47.418949] BUG: KASAN: slab-use-after-free in send_count+0x4c/0x6c [ 47.419029] Read of size 1 at addr ffff000015943228 by task c2_race/191 [ 47.419546] send_count+0x4c/0x6c [ 47.419591] mgmt_mesh_foreach+0x68/0x100 [ 47.419637] mesh_features+0x180/0x184 [ 47.421345] Freed by task 59: [ 47.421555] mgmt_mesh_remove+0x94/0x110 [ 47.421589] send_cancel+0xd8/0x1cc [ 47.421627] hci_cmd_sync_work+0xac/0x128 Offset 40 of the freed 96-byte object is mesh_tx->handle, the byte send_count() puts in the MESH_READ_FEATURES reply. The walk also follows the LIST_POISON1 left by the concurrent list_del(), which oopses with hci_dev_lock held and never released, so every later mgmt command on that controller blocks. The same missing lock lets the worker free the object under mesh_send(), which reads mesh_tx->handle into the command complete after queueing: [ 41.093914] BUG: KASAN: slab-use-after-free in mgmt_cmd_complete+0xd0/0x= 210 [ 41.094353] Read of size 1 at addr ffff00000a0dea28 by task c1_poc/162 [ 41.096944] mgmt_mesh_remove+0x94/0x110 [ 41.096975] mesh_send_start_complete+0x128/0x160 That read already sits inside mesh_send()'s hci_dev_lock() section; it is the worker side that is missing the lock. Take hci_dev_lock(hdev) on the worker side, around the list work only and not around hci_disable_advertising_sync(), and assert it in the helpers that walk or extend the list. hci_req_sync_lock -> hdev->lock is the order this subsystem already uses: hci_cmd_sync_work() calls entry->func under req_lock, and callbacks such as hci_update_eir_sync() take hci_dev_lock() inside it. mesh_next() and mesh_send_start_complete() are destroy callbacks, and hci_cmd_sync_clear() runs a destroy callback under cmd_sync_work_lock, which every mgmt caller of hci_cmd_sync_queue() takes with hdev->lock already held. Both therefore return before hci_dev_lock() when err is -ECANCELED, as the other destroy callbacks in this file do. Without those returns lockdep reports a circular dependency, reached by closing /dev/vhci while a mesh entry is queued behind a parked req_workqueue: [ 78.211873] ffff00001b0340b8 (&hdev->lock){+.+.}-{4:4}, at: mesh_send_st= art_complete+0x88/0xf4 but task is already holding lock: [ 78.212596] ffff00001b0347c0 (&hdev->cmd_sync_work_lock){+.+.}-{4:4}, at= : hci_cmd_sync_clear+0x60/0xd4 -> #1 (&hdev->cmd_sync_work_lock){+.+.}-{4:4}: [ 78.214268] hci_update_passive_scan+0x6c/0x84 [ 78.214455] mgmt_set_powered_complete+0x1b0/0x1f8 The other leg of the cycle, mgmt_set_powered_complete() calling hci_update_passive_scan() with hdev->lock held, is an existing in-tree path. The entry such a return leaves on hdev->mesh_pending stays there, as entries already do across an unregister. Discovered by XBOW, triaged by Baul Lee Fixes: b338d91703fa ("Bluetooth: Implement support for Mesh") Fixes: 3bb88524b7d0 ("Bluetooth: MGMT: iterate over mesh commands in mgmt_m= esh_foreach()") Cc: stable@vger.kernel.org Signed-off-by: Baul Lee --- net/bluetooth/mgmt.c | 30 ++++++++++++++++++++++++++++-- net/bluetooth/mgmt_util.c | 8 ++++++++ 2 files changed, 36 insertions(+), 2 deletions(-) diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c index 97408904f74b..853a80fd15af 100644 --- a/net/bluetooth/mgmt.c +++ b/net/bluetooth/mgmt.c @@ -1087,6 +1087,8 @@ static void mesh_send_complete(struct hci_dev *hdev, { u8 handle =3D mesh_tx->handle; =20 + lockdep_assert_held(&hdev->lock); + if (!silent) mgmt_event(MGMT_EV_MESH_PACKET_CMPLT, hdev, &handle, sizeof(handle), NULL); @@ -1101,11 +1103,16 @@ static int mesh_send_done_sync(struct hci_dev *hdev= , void *data) hci_dev_clear_flag(hdev, HCI_MESH_SENDING); if (list_empty(&hdev->adv_instances)) hci_disable_advertising_sync(hdev); + + hci_dev_lock(hdev); + mesh_tx =3D mgmt_mesh_next(hdev, NULL); =20 if (mesh_tx) mesh_send_complete(hdev, mesh_tx, false); =20 + hci_dev_unlock(hdev); + return 0; } =20 @@ -1113,11 +1120,19 @@ static int mesh_send_sync(struct hci_dev *hdev, voi= d *data); static void mesh_send_start_complete(struct hci_dev *hdev, void *data, int= err); static void mesh_next(struct hci_dev *hdev, void *data, int err) { - struct mgmt_mesh_tx *mesh_tx =3D mgmt_mesh_next(hdev, NULL); + struct mgmt_mesh_tx *mesh_tx; =20 - if (!mesh_tx) + if (err =3D=3D -ECANCELED) return; =20 + hci_dev_lock(hdev); + + mesh_tx =3D mgmt_mesh_next(hdev, NULL); + if (!mesh_tx) { + hci_dev_unlock(hdev); + return; + } + err =3D hci_cmd_sync_queue(hdev, mesh_send_sync, mesh_tx, mesh_send_start_complete); =20 @@ -1125,6 +1140,8 @@ static void mesh_next(struct hci_dev *hdev, void *dat= a, int err) mesh_send_complete(hdev, mesh_tx, false); else hci_dev_set_flag(hdev, HCI_MESH_SENDING); + + hci_dev_unlock(hdev); } =20 static void mesh_send_done(struct work_struct *work) @@ -2310,12 +2327,17 @@ static void mesh_send_start_complete(struct hci_dev= *hdev, void *data, int err) unsigned long mesh_send_interval; u8 mgmt_err =3D mgmt_status(err); =20 + if (err =3D=3D -ECANCELED) + return; + /* Report any errors here, but don't report completion */ =20 if (mgmt_err) { hci_dev_clear_flag(hdev, HCI_MESH_SENDING); /* Send Complete Error Code for handle */ + hci_dev_lock(hdev); mesh_send_complete(hdev, mesh_tx, false); + hci_dev_unlock(hdev); return; } =20 @@ -2421,6 +2443,8 @@ static int send_cancel(struct hci_dev *hdev, void *da= ta) struct mgmt_cp_mesh_send_cancel *cancel =3D (void *)cmd->param; struct mgmt_mesh_tx *mesh_tx; =20 + hci_dev_lock(hdev); + if (!cancel->handle) { do { mesh_tx =3D mgmt_mesh_next(hdev, cmd->sk); @@ -2435,6 +2459,8 @@ static int send_cancel(struct hci_dev *hdev, void *da= ta) mesh_send_complete(hdev, mesh_tx, false); } =20 + hci_dev_unlock(hdev); + mgmt_cmd_complete(cmd->sk, hdev->id, MGMT_OP_MESH_SEND_CANCEL, 0, NULL, 0); =20 diff --git a/net/bluetooth/mgmt_util.c b/net/bluetooth/mgmt_util.c index 6ea107c0e054..a822091f2907 100644 --- a/net/bluetooth/mgmt_util.c +++ b/net/bluetooth/mgmt_util.c @@ -369,6 +369,8 @@ void mgmt_mesh_foreach(struct hci_dev *hdev, { struct mgmt_mesh_tx *mesh_tx, *tmp; 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Fri, 07 Aug 2026 03:15:46 -0700 (PDT) Received: from localhost.localdomain ([1.220.41.130]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-39085dea04bsm4399162a91.8.2026.08.07.03.15.43 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Fri, 07 Aug 2026 03:15:46 -0700 (PDT) From: Baul Lee To: Luiz Augusto von Dentz , Marcel Holtmann , Brian Gix Cc: Baul Lee , Luiz Augusto von Dentz , Dmitry Antipov , linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org, federico.kirschbaum@xbow.com, stable@vger.kernel.org Subject: [PATCH v2 3/3] Bluetooth: MGMT: reference-count struct mgmt_mesh_tx Date: Fri, 7 Aug 2026 19:15:29 +0900 Message-ID: <20260807101529.17348-4-baul.lee@xbow.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20260807101529.17348-1-baul.lee@xbow.com> References: <20260807101529.17348-1-baul.lee@xbow.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" hci_cmd_sync_submit() stores the caller's pointer in a work entry and takes no reference to what it names. hci_cmd_sync_work() drains that list from the head on an ordered workqueue, so an entry queued earlier runs to completion before a later one is looked at. mesh_send() links a struct mgmt_mesh_tx onto hdev->mesh_pending and queues mesh_send_sync() with the raw pointer. A MESH_SEND_CANCEL issued before that send leaves its send_cancel() entry ahead in the queue, so send_cancel() runs first: it picks the object out of hdev->mesh_pending with mgmt_mesh_next(), which returns it without unlinking it, and frees it through mesh_send_complete(). Nothing invalidates the pointer the later entry still holds, so mesh_send_sync() and its destroy callback mesh_send_start_complete() run on freed memory: [ 43.618774] BUG: KASAN: slab-use-after-free in mesh_send_sync+0xec/0x1b4 [ 43.618851] Write of size 1 at addr ffff000009f2a6a9 by task kworker/u5:= 2/148 [ 43.619464] mesh_send_sync+0xec/0x1b4 [ 43.619531] hci_cmd_sync_work+0xac/0x128 [ 43.620882] Freed by task 148: [ 43.621171] mgmt_mesh_remove+0x94/0x110 [ 43.621218] send_cancel+0xd8/0x1cc [ 43.621270] hci_cmd_sync_work+0xac/0x128 Offset 41 is mesh_tx->instance, the only byte mesh_send_sync() stores through mesh_tx; it reads further fields of the same freed object, and hci_set_adv_instance_data() copies 31 of those bytes into a live struct adv_info. The free and the use are consecutive iterations of one hci_cmd_sync_work() loop on one kworker, so queue order alone decides it. Give struct mgmt_mesh_tx a reference count. hdev->mesh_pending holds one, and every pointer handed to hci_cmd_sync_queue() takes a second one that the destroy callback drops, so a cancel that unlinks the object while a work entry is still queued no longer releases it. mgmt_mesh_remove() becomes an unlink plus a put and returns early when the object is already unlinked, because it can now outlive its removal from the list. The list reference is still dropped under hci_dev_lock() only, so mesh_send()'s use of mesh_tx->handle after queueing stays covered by the lock it holds. A cancel that arrives before the queued mesh_send_sync() now lets that send run rather than freeing the object under it; suppressing the transmission as well is a separate change. hci_cmd_sync_dequeue() is the other in-tree option, but mgmt_mesh_remove() is not given the hci_dev it needs and cannot tell whether the work entry has already been taken off cmd_sync_work_list. Discovered by XBOW, triaged by Baul Lee Fixes: b338d91703fa ("Bluetooth: Implement support for Mesh") Cc: stable@vger.kernel.org Signed-off-by: Baul Lee --- net/bluetooth/mgmt.c | 25 +++++++++++++++++-------- net/bluetooth/mgmt_util.c | 23 +++++++++++++++++++++-- net/bluetooth/mgmt_util.h | 3 +++ 3 files changed, 41 insertions(+), 10 deletions(-) diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c index 853a80fd15af..61d279ae2f71 100644 --- a/net/bluetooth/mgmt.c +++ b/net/bluetooth/mgmt.c @@ -1133,13 +1133,15 @@ static void mesh_next(struct hci_dev *hdev, void *d= ata, int err) return; } =20 - err =3D hci_cmd_sync_queue(hdev, mesh_send_sync, mesh_tx, + err =3D hci_cmd_sync_queue(hdev, mesh_send_sync, mgmt_mesh_get(mesh_tx), mesh_send_start_complete); =20 - if (err < 0) + if (err < 0) { + mgmt_mesh_put(mesh_tx); mesh_send_complete(hdev, mesh_tx, false); - else + } else { hci_dev_set_flag(hdev, HCI_MESH_SENDING); + } =20 hci_dev_unlock(hdev); } @@ -2328,7 +2330,7 @@ static void mesh_send_start_complete(struct hci_dev *= hdev, void *data, int err) u8 mgmt_err =3D mgmt_status(err); =20 if (err =3D=3D -ECANCELED) - return; + goto put; =20 /* Report any errors here, but don't report completion */ =20 @@ -2338,12 +2340,15 @@ static void mesh_send_start_complete(struct hci_dev= *hdev, void *data, int err) hci_dev_lock(hdev); mesh_send_complete(hdev, mesh_tx, false); hci_dev_unlock(hdev); - return; + goto put; } =20 mesh_send_interval =3D msecs_to_jiffies((send->cnt) * 25); queue_delayed_work(hdev->req_workqueue, &hdev->mesh_send_done, mesh_send_interval); + +put: + mgmt_mesh_put(mesh_tx); } =20 static int mesh_send_sync(struct hci_dev *hdev, void *data) @@ -2549,11 +2554,15 @@ static int mesh_send(struct sock *sk, struct hci_de= v *hdev, void *data, u16 len) sending =3D hci_dev_test_flag(hdev, HCI_MESH_SENDING); mesh_tx =3D mgmt_mesh_add(sk, hdev, send, len); =20 - if (!mesh_tx) + if (!mesh_tx) { err =3D -ENOMEM; - else if (!sending) - err =3D hci_cmd_sync_queue(hdev, mesh_send_sync, mesh_tx, + } else if (!sending) { + err =3D hci_cmd_sync_queue(hdev, mesh_send_sync, + mgmt_mesh_get(mesh_tx), mesh_send_start_complete); + if (err < 0) + mgmt_mesh_put(mesh_tx); + } =20 if (err < 0) { bt_dev_err(hdev, "Send Mesh Failed %d", err); diff --git a/net/bluetooth/mgmt_util.c b/net/bluetooth/mgmt_util.c index a822091f2907..c7543964525a 100644 --- a/net/bluetooth/mgmt_util.c +++ b/net/bluetooth/mgmt_util.c @@ -422,6 +422,7 @@ struct mgmt_mesh_tx *mgmt_mesh_add(struct sock *sk, str= uct hci_dev *hdev, if (!mesh_tx) return NULL; =20 + refcount_set(&mesh_tx->ref, 1); hdev->mesh_send_ref++; if (!hdev->mesh_send_ref) hdev->mesh_send_ref++; @@ -438,9 +439,27 @@ struct mgmt_mesh_tx *mgmt_mesh_add(struct sock *sk, st= ruct hci_dev *hdev, return mesh_tx; } =20 -void mgmt_mesh_remove(struct mgmt_mesh_tx *mesh_tx) +struct mgmt_mesh_tx *mgmt_mesh_get(struct mgmt_mesh_tx *mesh_tx) +{ + refcount_inc(&mesh_tx->ref); + + return mesh_tx; +} + +void mgmt_mesh_put(struct mgmt_mesh_tx *mesh_tx) { - list_del(&mesh_tx->list); + if (!refcount_dec_and_test(&mesh_tx->ref)) + return; + sock_put(mesh_tx->sk); kfree(mesh_tx); } + +void mgmt_mesh_remove(struct mgmt_mesh_tx *mesh_tx) +{ + if (list_empty(&mesh_tx->list)) + return; + + list_del_init(&mesh_tx->list); + mgmt_mesh_put(mesh_tx); +} diff --git a/net/bluetooth/mgmt_util.h b/net/bluetooth/mgmt_util.h index 20810cf06e81..b38970c1332c 100644 --- a/net/bluetooth/mgmt_util.h +++ b/net/bluetooth/mgmt_util.h @@ -19,6 +19,7 @@ =20 struct mgmt_mesh_tx { struct list_head list; + refcount_t ref; int index; size_t param_len; struct sock *sk; @@ -72,4 +73,6 @@ struct mgmt_mesh_tx *mgmt_mesh_find(struct hci_dev *hdev,= u8 handle); struct mgmt_mesh_tx *mgmt_mesh_next(struct hci_dev *hdev, struct sock *sk); struct mgmt_mesh_tx *mgmt_mesh_add(struct sock *sk, struct hci_dev *hdev, void *data, u16 len); +struct mgmt_mesh_tx *mgmt_mesh_get(struct mgmt_mesh_tx *mesh_tx); +void mgmt_mesh_put(struct mgmt_mesh_tx *mesh_tx); void mgmt_mesh_remove(struct mgmt_mesh_tx *mesh_tx); --=20 2.50.1 (Apple Git-155)