[PATCH v6 1/3] Bluetooth: hci_event: Fix UAF in hci_conn_tx_dequeue

[PATCH v6 1/3] Bluetooth: hci_event: Fix UAF in hci_conn_tx_dequeue

[Luiz Augusto von Dentz]

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

This fixes the following UAF caused by not properly locking hdev when
processing HCI_EV_NUM_COMP_PKTS:

BUG: KASAN: slab-use-after-free in hci_conn_tx_dequeue+0x1be/0x220 net/bluetooth/hci_conn.c:3036
Read of size 4 at addr ffff8880740f0940 by task kworker/u11:0/54

CPU: 1 UID: 0 PID: 54 Comm: kworker/u11:0 Not tainted 6.16.0-rc7 #3 PREEMPT(full)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
Workqueue: hci1 hci_rx_work
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x230 mm/kasan/report.c:480
 kasan_report+0x118/0x150 mm/kasan/report.c:593
 hci_conn_tx_dequeue+0x1be/0x220 net/bluetooth/hci_conn.c:3036
 hci_num_comp_pkts_evt+0x1c8/0xa50 net/bluetooth/hci_event.c:4404
 hci_event_func net/bluetooth/hci_event.c:7477 [inline]
 hci_event_packet+0x7e0/0x1200 net/bluetooth/hci_event.c:7531
 hci_rx_work+0x46a/0xe80 net/bluetooth/hci_core.c:4070
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 home/kwqcheii/source/fuzzing/kernel/kasan/linux-6.16-rc7/arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 54:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4359
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 __hci_conn_add+0x233/0x1b30 net/bluetooth/hci_conn.c:939
 le_conn_complete_evt+0x3d6/0x1220 net/bluetooth/hci_event.c:5628
 hci_le_enh_conn_complete_evt+0x189/0x470 net/bluetooth/hci_event.c:5794
 hci_event_func net/bluetooth/hci_event.c:7474 [inline]
 hci_event_packet+0x78c/0x1200 net/bluetooth/hci_event.c:7531
 hci_rx_work+0x46a/0xe80 net/bluetooth/hci_core.c:4070
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 home/kwqcheii/source/fuzzing/kernel/kasan/linux-6.16-rc7/arch/x86/entry/entry_64.S:245

Freed by task 9572:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2381 [inline]
 slab_free mm/slub.c:4643 [inline]
 kfree+0x18e/0x440 mm/slub.c:4842
 device_release+0x9c/0x1c0
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x22b/0x480 lib/kobject.c:737
 hci_conn_cleanup net/bluetooth/hci_conn.c:175 [inline]
 hci_conn_del+0x8ff/0xcb0 net/bluetooth/hci_conn.c:1173
 hci_abort_conn_sync+0x5d1/0xdf0 net/bluetooth/hci_sync.c:5689
 hci_cmd_sync_work+0x210/0x3a0 net/bluetooth/hci_sync.c:332
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 home/kwqcheii/source/fuzzing/kernel/kasan/linux-6.16-rc7/arch/x86/entry/entry_64.S:245

Fixes: 134f4b39df7b ("Bluetooth: add support for skb TX SND/COMPLETION timestamping")
Reported-by: Junvyyang, Tencent Zhuque Lab <zhuque@tencent.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
---
 net/bluetooth/hci_event.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 571b7ca011c2..abb17dadf03c 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -4391,6 +4391,8 @@ static void hci_num_comp_pkts_evt(struct hci_dev *hdev, void *data,
 
 	bt_dev_dbg(hdev, "num %d", ev->num);
 
+	hci_dev_lock(hdev);
+
 	for (i = 0; i < ev->num; i++) {
 		struct hci_comp_pkts_info *info = &ev->handles[i];
 		struct hci_conn *conn;
@@ -4462,6 +4464,8 @@ static void hci_num_comp_pkts_evt(struct hci_dev *hdev, void *data,
 	}
 
 	queue_work(hdev->workqueue, &hdev->tx_work);
+
+	hci_dev_unlock(hdev);
 }
 
 static void hci_mode_change_evt(struct hci_dev *hdev, void *data,
-- 
2.51.0

[PATCH v6 2/3] Bluetooth: hci_event: Fix UAF in hci_acl_create_conn_sync

[Luiz Augusto von Dentz]

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

This fixes the following UFA in hci_acl_create_conn_sync where a
connection still pending is command submission (conn->state == BT_OPEN)
maybe freed, also since this also can happen with the likes of
hci_le_create_conn_sync fix it as well:

BUG: KASAN: slab-use-after-free in hci_acl_create_conn_sync+0x5ef/0x790 net/bluetooth/hci_sync.c:6861
Write of size 2 at addr ffff88805ffcc038 by task kworker/u11:2/9541

CPU: 1 UID: 0 PID: 9541 Comm: kworker/u11:2 Not tainted 6.16.0-rc7 #3 PREEMPT(full)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
Workqueue: hci3 hci_cmd_sync_work
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x230 mm/kasan/report.c:480
 kasan_report+0x118/0x150 mm/kasan/report.c:593
 hci_acl_create_conn_sync+0x5ef/0x790 net/bluetooth/hci_sync.c:6861
 hci_cmd_sync_work+0x210/0x3a0 net/bluetooth/hci_sync.c:332
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 home/kwqcheii/source/fuzzing/kernel/kasan/linux-6.16-rc7/arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 123736:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4359
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 __hci_conn_add+0x233/0x1b30 net/bluetooth/hci_conn.c:939
 hci_conn_add_unset net/bluetooth/hci_conn.c:1051 [inline]
 hci_connect_acl+0x16c/0x4e0 net/bluetooth/hci_conn.c:1634
 pair_device+0x418/0xa70 net/bluetooth/mgmt.c:3556
 hci_mgmt_cmd+0x9c9/0xef0 net/bluetooth/hci_sock.c:1719
 hci_sock_sendmsg+0x6ca/0xef0 net/bluetooth/hci_sock.c:1839
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x219/0x270 net/socket.c:727
 sock_write_iter+0x258/0x330 net/socket.c:1131
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x54b/0xa90 fs/read_write.c:686
 ksys_write+0x145/0x250 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 103680:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2381 [inline]
 slab_free mm/slub.c:4643 [inline]
 kfree+0x18e/0x440 mm/slub.c:4842
 device_release+0x9c/0x1c0
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x22b/0x480 lib/kobject.c:737
 hci_conn_cleanup net/bluetooth/hci_conn.c:175 [inline]
 hci_conn_del+0x8ff/0xcb0 net/bluetooth/hci_conn.c:1173
 hci_conn_complete_evt+0x3c7/0x1040 net/bluetooth/hci_event.c:3199
 hci_event_func net/bluetooth/hci_event.c:7477 [inline]
 hci_event_packet+0x7e0/0x1200 net/bluetooth/hci_event.c:7531
 hci_rx_work+0x46a/0xe80 net/bluetooth/hci_core.c:4070
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 home/kwqcheii/source/fuzzing/kernel/kasan/linux-6.16-rc7/arch/x86/entry/entry_64.S:245

Last potentially related work creation:
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:47
 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:548
 insert_work+0x3d/0x330 kernel/workqueue.c:2183
 __queue_work+0xbd9/0xfe0 kernel/workqueue.c:2345
 queue_delayed_work_on+0x18b/0x280 kernel/workqueue.c:2561
 pairing_complete+0x1e7/0x2b0 net/bluetooth/mgmt.c:3451
 pairing_complete_cb+0x1ac/0x230 net/bluetooth/mgmt.c:3487
 hci_connect_cfm include/net/bluetooth/hci_core.h:2064 [inline]
 hci_conn_failed+0x24d/0x310 net/bluetooth/hci_conn.c:1275
 hci_conn_complete_evt+0x3c7/0x1040 net/bluetooth/hci_event.c:3199
 hci_event_func net/bluetooth/hci_event.c:7477 [inline]
 hci_event_packet+0x7e0/0x1200 net/bluetooth/hci_event.c:7531
 hci_rx_work+0x46a/0xe80 net/bluetooth/hci_core.c:4070
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 home/kwqcheii/source/fuzzing/kernel/kasan/linux-6.16-rc7/arch/x86/entry/entry_64.S:245

Fixes: aef2aa4fa98e ("Bluetooth: hci_event: Fix creating hci_conn object on error status")
Reported-by: Junvyyang, Tencent Zhuque Lab <zhuque@tencent.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
---
 include/net/bluetooth/hci_core.h | 21 +++++++++++++++++++++
 net/bluetooth/hci_event.c        | 26 +++++++++++++++++++++++---
 2 files changed, 44 insertions(+), 3 deletions(-)

diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index 66523b74f828..2924c2bf2a98 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -1246,6 +1246,27 @@ static inline struct hci_conn *hci_conn_hash_lookup_ba(struct hci_dev *hdev,
 	return NULL;
 }
 
+static inline struct hci_conn *hci_conn_hash_lookup_role(struct hci_dev *hdev,
+							 __u8 type, __u8 role,
+							 bdaddr_t *ba)
+{
+	struct hci_conn_hash *h = &hdev->conn_hash;
+	struct hci_conn  *c;
+
+	rcu_read_lock();
+
+	list_for_each_entry_rcu(c, &h->list, list) {
+		if (c->type == type && c->role == role && !bacmp(&c->dst, ba)) {
+			rcu_read_unlock();
+			return c;
+		}
+	}
+
+	rcu_read_unlock();
+
+	return NULL;
+}
+
 static inline struct hci_conn *hci_conn_hash_lookup_le(struct hci_dev *hdev,
 						       bdaddr_t *ba,
 						       __u8 ba_type)
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index abb17dadf03c..d790b0d4eb9a 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -3087,8 +3087,18 @@ static void hci_conn_complete_evt(struct hci_dev *hdev, void *data,
 
 	hci_dev_lock(hdev);
 
+	/* Check for existing connection:
+	 *
+	 * 1. If it doesn't exist then it must be receiver/slave role.
+	 * 2. If it does exist confirm that it is connecting/BT_CONNECT in case
+	 *    of initiator/master role since there could be a collision where
+	 *    either side is attempting to connect or something like a fuzzing
+	 *    testing is trying to play tricks to destroy the hcon object before
+	 *    it even attempts to connect (e.g. hcon->state == BT_OPEN).
+	 */
 	conn = hci_conn_hash_lookup_ba(hdev, ev->link_type, &ev->bdaddr);
-	if (!conn) {
+	if (!conn ||
+	    (conn->role == HCI_ROLE_MASTER && conn->state != BT_CONNECT)) {
 		/* In case of error status and there is no connection pending
 		 * just unlock as there is nothing to cleanup.
 		 */
@@ -5628,8 +5638,18 @@ static void le_conn_complete_evt(struct hci_dev *hdev, u8 status,
 	 */
 	hci_dev_clear_flag(hdev, HCI_LE_ADV);
 
-	conn = hci_conn_hash_lookup_ba(hdev, LE_LINK, bdaddr);
-	if (!conn) {
+	/* Check for existing connection:
+	 *
+	 * 1. If it doesn't exist then use the role to create a new object.
+	 * 2. If it does exist confirm that it is connecting/BT_CONNECT in case
+	 *    of initiator/master role since there could be a collision where
+	 *    either side is attempting to connect or something like a fuzzing
+	 *    testing is trying to play tricks to destroy the hcon object before
+	 *    it even attempts to connect (e.g. hcon->state == BT_OPEN).
+	 */
+	conn = hci_conn_hash_lookup_role(hdev, LE_LINK, role, bdaddr);
+	if (!conn ||
+	    (conn->role == HCI_ROLE_MASTER && conn->state != BT_CONNECT)) {
 		/* In case of error status and there is no connection pending
 		 * just unlock as there is nothing to cleanup.
 		 */
-- 
2.51.0

[PATCH v6 3/3] Bluetooth: MGMT: Fix possible UAFs

[Luiz Augusto von Dentz]

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

This attemps to fix possible UAFs caused by struct mgmt_pending being
freed while still being processed like in the following trace, in order
to fix mgmt_pending_valid is introduce and use to check if the
mgmt_pending hasn't been removed from the pending list, on the complete
callbacks it is used to check and in addtion remove the cmd from the list
while holding mgmt_pending_lock to avoid TOCTOU problems since if the cmd
is left on the list it can still be accessed and freed.

BUG: KASAN: slab-use-after-free in mgmt_add_adv_patterns_monitor_sync+0x35/0x50 net/bluetooth/mgmt.c:5223
Read of size 8 at addr ffff8880709d4dc0 by task kworker/u11:0/55

CPU: 0 UID: 0 PID: 55 Comm: kworker/u11:0 Not tainted 6.16.4 #2 PREEMPT(full)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
Workqueue: hci0 hci_cmd_sync_work
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 mgmt_add_adv_patterns_monitor_sync+0x35/0x50 net/bluetooth/mgmt.c:5223
 hci_cmd_sync_work+0x210/0x3a0 net/bluetooth/hci_sync.c:332
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 home/kwqcheii/source/fuzzing/kernel/kasan/linux-6.16.4/arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 12210:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4364
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 mgmt_pending_new+0x65/0x1e0 net/bluetooth/mgmt_util.c:269
 mgmt_pending_add+0x35/0x140 net/bluetooth/mgmt_util.c:296
 __add_adv_patterns_monitor+0x130/0x200 net/bluetooth/mgmt.c:5247
 add_adv_patterns_monitor+0x214/0x360 net/bluetooth/mgmt.c:5364
 hci_mgmt_cmd+0x9c9/0xef0 net/bluetooth/hci_sock.c:1719
 hci_sock_sendmsg+0x6ca/0xef0 net/bluetooth/hci_sock.c:1839
 sock_sendmsg_nosec net/socket.c:714 [inline]
 __sock_sendmsg+0x219/0x270 net/socket.c:729
 sock_write_iter+0x258/0x330 net/socket.c:1133
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x5c9/0xb30 fs/read_write.c:686
 ksys_write+0x145/0x250 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 12221:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2381 [inline]
 slab_free mm/slub.c:4648 [inline]
 kfree+0x18e/0x440 mm/slub.c:4847
 mgmt_pending_free net/bluetooth/mgmt_util.c:311 [inline]
 mgmt_pending_foreach+0x30d/0x380 net/bluetooth/mgmt_util.c:257
 __mgmt_power_off+0x169/0x350 net/bluetooth/mgmt.c:9444
 hci_dev_close_sync+0x754/0x1330 net/bluetooth/hci_sync.c:5290
 hci_dev_do_close net/bluetooth/hci_core.c:501 [inline]
 hci_dev_close+0x108/0x200 net/bluetooth/hci_core.c:526
 sock_do_ioctl+0xd9/0x300 net/socket.c:1192
 sock_ioctl+0x576/0x790 net/socket.c:1313
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Fixes: b747a83690c8 ("Bluetooth: hci_sync: Refactor add Adv Monitor")
Closes: https://syzkaller.appspot.com/bug?extid=e8651419c44dbc2b8768
Reported-by: syzbot+e8651419c44dbc2b8768@syzkaller.appspotmail.com
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
---
 net/bluetooth/mgmt.c      | 193 +++++++++++++++++++++++++-------------
 net/bluetooth/mgmt_util.c |  23 +++++
 net/bluetooth/mgmt_util.h |   2 +
 3 files changed, 154 insertions(+), 64 deletions(-)

diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index 989321b1ea27..b9c53810bf06 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -1323,8 +1323,7 @@ static void mgmt_set_powered_complete(struct hci_dev *hdev, void *data, int err)
 	struct mgmt_mode *cp;
 
 	/* Make sure cmd still outstanding. */
-	if (err == -ECANCELED ||
-	    cmd != pending_find(MGMT_OP_SET_POWERED, hdev))
+	if (err == -ECANCELED || !mgmt_pending_valid(hdev, cmd, true))
 		return;
 
 	cp = cmd->param;
@@ -1351,7 +1350,7 @@ static void mgmt_set_powered_complete(struct hci_dev *hdev, void *data, int err)
 				mgmt_status(err));
 	}
 
-	mgmt_pending_remove(cmd);
+	mgmt_pending_free(cmd);
 }
 
 static int set_powered_sync(struct hci_dev *hdev, void *data)
@@ -1360,7 +1359,7 @@ static int set_powered_sync(struct hci_dev *hdev, void *data)
 	struct mgmt_mode *cp;
 
 	/* Make sure cmd still outstanding. */
-	if (cmd != pending_find(MGMT_OP_SET_POWERED, hdev))
+	if (!mgmt_pending_valid(hdev, cmd, false))
 		return -ECANCELED;
 
 	cp = cmd->param;
@@ -1516,8 +1515,7 @@ static void mgmt_set_discoverable_complete(struct hci_dev *hdev, void *data,
 	bt_dev_dbg(hdev, "err %d", err);
 
 	/* Make sure cmd still outstanding. */
-	if (err == -ECANCELED ||
-	    cmd != pending_find(MGMT_OP_SET_DISCOVERABLE, hdev))
+	if (err == -ECANCELED || !mgmt_pending_valid(hdev, cmd, true))
 		return;
 
 	hci_dev_lock(hdev);
@@ -1539,12 +1537,15 @@ static void mgmt_set_discoverable_complete(struct hci_dev *hdev, void *data,
 	new_settings(hdev, cmd->sk);
 
 done:
-	mgmt_pending_remove(cmd);
+	mgmt_pending_free(cmd);
 	hci_dev_unlock(hdev);
 }
 
 static int set_discoverable_sync(struct hci_dev *hdev, void *data)
 {
+	if (!mgmt_pending_valid(hdev, data, false))
+		return -ECANCELED;
+
 	BT_DBG("%s", hdev->name);
 
 	return hci_update_discoverable_sync(hdev);
@@ -1691,8 +1692,7 @@ static void mgmt_set_connectable_complete(struct hci_dev *hdev, void *data,
 	bt_dev_dbg(hdev, "err %d", err);
 
 	/* Make sure cmd still outstanding. */
-	if (err == -ECANCELED ||
-	    cmd != pending_find(MGMT_OP_SET_CONNECTABLE, hdev))
+	if (err == -ECANCELED || !mgmt_pending_valid(hdev, cmd, true))
 		return;
 
 	hci_dev_lock(hdev);
@@ -1707,7 +1707,7 @@ static void mgmt_set_connectable_complete(struct hci_dev *hdev, void *data,
 	new_settings(hdev, cmd->sk);
 
 done:
-	mgmt_pending_remove(cmd);
+	mgmt_pending_free(cmd);
 
 	hci_dev_unlock(hdev);
 }
@@ -1743,6 +1743,9 @@ static int set_connectable_update_settings(struct hci_dev *hdev,
 
 static int set_connectable_sync(struct hci_dev *hdev, void *data)
 {
+	if (!mgmt_pending_valid(hdev, data, false))
+		return -ECANCELED;
+
 	BT_DBG("%s", hdev->name);
 
 	return hci_update_connectable_sync(hdev);
@@ -1919,14 +1922,17 @@ static void set_ssp_complete(struct hci_dev *hdev, void *data, int err)
 {
 	struct cmd_lookup match = { NULL, hdev };
 	struct mgmt_pending_cmd *cmd = data;
-	struct mgmt_mode *cp = cmd->param;
-	u8 enable = cp->val;
+	struct mgmt_mode *cp;
+	u8 enable;
 	bool changed;
 
 	/* Make sure cmd still outstanding. */
-	if (err == -ECANCELED || cmd != pending_find(MGMT_OP_SET_SSP, hdev))
+	if (err == -ECANCELED || !mgmt_pending_valid(hdev, cmd, true))
 		return;
 
+	cp = cmd->param;
+	enable = cp->val;
+
 	if (err) {
 		u8 mgmt_err = mgmt_status(err);
 
@@ -1935,8 +1941,7 @@ static void set_ssp_complete(struct hci_dev *hdev, void *data, int err)
 			new_settings(hdev, NULL);
 		}
 
-		mgmt_pending_foreach(MGMT_OP_SET_SSP, hdev, true,
-				     cmd_status_rsp, &mgmt_err);
+		mgmt_cmd_status(cmd->sk, cmd->hdev->id, cmd->opcode, mgmt_err);
 		return;
 	}
 
@@ -1946,7 +1951,7 @@ static void set_ssp_complete(struct hci_dev *hdev, void *data, int err)
 		changed = hci_dev_test_and_clear_flag(hdev, HCI_SSP_ENABLED);
 	}
 
-	mgmt_pending_foreach(MGMT_OP_SET_SSP, hdev, true, settings_rsp, &match);
+	settings_rsp(cmd, &match);
 
 	if (changed)
 		new_settings(hdev, match.sk);
@@ -1960,10 +1965,15 @@ static void set_ssp_complete(struct hci_dev *hdev, void *data, int err)
 static int set_ssp_sync(struct hci_dev *hdev, void *data)
 {
 	struct mgmt_pending_cmd *cmd = data;
-	struct mgmt_mode *cp = cmd->param;
+	struct mgmt_mode *cp;
 	bool changed = false;
 	int err;
 
+	if (!mgmt_pending_valid(hdev, cmd, false))
+		return -ECANCELED;
+
+	cp = cmd->param;
+
 	if (cp->val)
 		changed = !hci_dev_test_and_set_flag(hdev, HCI_SSP_ENABLED);
 
@@ -2060,32 +2070,44 @@ static int set_hs(struct sock *sk, struct hci_dev *hdev, void *data, u16 len)
 
 static void set_le_complete(struct hci_dev *hdev, void *data, int err)
 {
+	struct mgmt_pending_cmd *cmd = data;
 	struct cmd_lookup match = { NULL, hdev };
 	u8 status = mgmt_status(err);
 
 	bt_dev_dbg(hdev, "err %d", err);
 
-	if (status) {
-		mgmt_pending_foreach(MGMT_OP_SET_LE, hdev, true, cmd_status_rsp,
-				     &status);
+	if (err == -ECANCELED || !mgmt_pending_valid(hdev, data, true))
 		return;
+
+	if (status) {
+		mgmt_cmd_status(cmd->sk, cmd->hdev->id, cmd->opcode, status);
+		goto done;
 	}
 
-	mgmt_pending_foreach(MGMT_OP_SET_LE, hdev, true, settings_rsp, &match);
+	settings_rsp(cmd, &match);
 
 	new_settings(hdev, match.sk);
 
 	if (match.sk)
 		sock_put(match.sk);
+
+done:
+	mgmt_pending_free(cmd);
 }
 
 static int set_le_sync(struct hci_dev *hdev, void *data)
 {
 	struct mgmt_pending_cmd *cmd = data;
-	struct mgmt_mode *cp = cmd->param;
-	u8 val = !!cp->val;
+	struct mgmt_mode *cp;
+	u8 val;
 	int err;
 
+	if (!mgmt_pending_valid(hdev, cmd, false))
+		return -ECANCELED;
+
+	cp = cmd->param;
+	val = !!cp->val;
+
 	if (!val) {
 		hci_clear_adv_instance_sync(hdev, NULL, 0x00, true);
 
@@ -2127,7 +2149,12 @@ static void set_mesh_complete(struct hci_dev *hdev, void *data, int err)
 {
 	struct mgmt_pending_cmd *cmd = data;
 	u8 status = mgmt_status(err);
-	struct sock *sk = cmd->sk;
+	struct sock *sk;
+
+	if (err == -ECANCELED || !mgmt_pending_valid(hdev, cmd, true))
+		return;
+
+	sk = cmd->sk;
 
 	if (status) {
 		mgmt_pending_foreach(MGMT_OP_SET_MESH_RECEIVER, hdev, true,
@@ -2142,8 +2169,14 @@ static void set_mesh_complete(struct hci_dev *hdev, void *data, int err)
 static int set_mesh_sync(struct hci_dev *hdev, void *data)
 {
 	struct mgmt_pending_cmd *cmd = data;
-	struct mgmt_cp_set_mesh *cp = cmd->param;
-	size_t len = cmd->param_len;
+	struct mgmt_cp_set_mesh *cp;
+	size_t len;
+
+	if (!mgmt_pending_valid(hdev, cmd, false))
+		return -ECANCELED;
+
+	cp = cmd->param;
+	len = cmd->param_len;
 
 	memset(hdev->mesh_ad_types, 0, sizeof(hdev->mesh_ad_types));
 
@@ -3867,15 +3900,16 @@ static int name_changed_sync(struct hci_dev *hdev, void *data)
 static void set_name_complete(struct hci_dev *hdev, void *data, int err)
 {
 	struct mgmt_pending_cmd *cmd = data;
-	struct mgmt_cp_set_local_name *cp = cmd->param;
+	struct mgmt_cp_set_local_name *cp;
 	u8 status = mgmt_status(err);
 
 	bt_dev_dbg(hdev, "err %d", err);
 
-	if (err == -ECANCELED ||
-	    cmd != pending_find(MGMT_OP_SET_LOCAL_NAME, hdev))
+	if (err == -ECANCELED || !mgmt_pending_valid(hdev, cmd, true))
 		return;
 
+	cp = cmd->param;
+
 	if (status) {
 		mgmt_cmd_status(cmd->sk, hdev->id, MGMT_OP_SET_LOCAL_NAME,
 				status);
@@ -3887,13 +3921,18 @@ static void set_name_complete(struct hci_dev *hdev, void *data, int err)
 			hci_cmd_sync_queue(hdev, name_changed_sync, NULL, NULL);
 	}
 
-	mgmt_pending_remove(cmd);
+	mgmt_pending_free(cmd);
 }
 
 static int set_name_sync(struct hci_dev *hdev, void *data)
 {
 	struct mgmt_pending_cmd *cmd = data;
-	struct mgmt_cp_set_local_name *cp = cmd->param;
+	struct mgmt_cp_set_local_name *cp;
+
+	if (!mgmt_pending_valid(hdev, cmd, false))
+		return -ECANCELED;
+
+	cp = cmd->param;
 
 	if (lmp_bredr_capable(hdev)) {
 		hci_update_name_sync(hdev, cp->name);
@@ -4048,13 +4087,14 @@ int mgmt_phy_configuration_changed(struct hci_dev *hdev, struct sock *skip)
 static void set_default_phy_complete(struct hci_dev *hdev, void *data, int err)
 {
 	struct mgmt_pending_cmd *cmd = data;
-	struct sk_buff *skb = cmd->skb;
+	struct sk_buff *skb;
 	u8 status = mgmt_status(err);
 
-	if (err == -ECANCELED ||
-	    cmd != pending_find(MGMT_OP_SET_PHY_CONFIGURATION, hdev))
+	if (err == -ECANCELED || !mgmt_pending_valid(hdev, cmd, true))
 		return;
 
+	skb = cmd->skb;
+
 	if (!status) {
 		if (!skb)
 			status = MGMT_STATUS_FAILED;
@@ -4080,15 +4120,21 @@ static void set_default_phy_complete(struct hci_dev *hdev, void *data, int err)
 	if (skb && !IS_ERR(skb))
 		kfree_skb(skb);
 
-	mgmt_pending_remove(cmd);
+	mgmt_pending_free(cmd);
 }
 
 static int set_default_phy_sync(struct hci_dev *hdev, void *data)
 {
 	struct mgmt_pending_cmd *cmd = data;
-	struct mgmt_cp_set_phy_configuration *cp = cmd->param;
+	struct mgmt_cp_set_phy_configuration *cp;
 	struct hci_cp_le_set_default_phy cp_phy;
-	u32 selected_phys = __le32_to_cpu(cp->selected_phys);
+	u32 selected_phys;
+
+	if (!mgmt_pending_valid(hdev, cmd, false))
+		return -ECANCELED;
+
+	cp = cmd->param;
+	selected_phys = __le32_to_cpu(cp->selected_phys);
 
 	memset(&cp_phy, 0, sizeof(cp_phy));
 
@@ -5187,7 +5233,17 @@ static void mgmt_add_adv_patterns_monitor_complete(struct hci_dev *hdev,
 {
 	struct mgmt_rp_add_adv_patterns_monitor rp;
 	struct mgmt_pending_cmd *cmd = data;
-	struct adv_monitor *monitor = cmd->user_data;
+	struct adv_monitor *monitor;
+
+	/* This is likely the result of hdev being closed and mgmt_index_removed
+	 * is attempting to clean up any pending command so
+	 * hci_adv_monitors_clear is about to be called which will take care of
+	 * freeing the adv_monitor instances.
+	 */
+	if (status == -ECANCELED && !mgmt_pending_valid(hdev, cmd, true))
+		return;
+
+	monitor = cmd->user_data;
 
 	hci_dev_lock(hdev);
 
@@ -5213,9 +5269,11 @@ static void mgmt_add_adv_patterns_monitor_complete(struct hci_dev *hdev,
 static int mgmt_add_adv_patterns_monitor_sync(struct hci_dev *hdev, void *data)
 {
 	struct mgmt_pending_cmd *cmd = data;
-	struct adv_monitor *monitor = cmd->user_data;
 
-	return hci_add_adv_monitor(hdev, monitor);
+	if (!mgmt_pending_valid(hdev, cmd, false))
+		return -ECANCELED;
+
+	return hci_add_adv_monitor(hdev, cmd->user_data);
 }
 
 static int __add_adv_patterns_monitor(struct sock *sk, struct hci_dev *hdev,
@@ -5482,7 +5540,8 @@ static int remove_adv_monitor(struct sock *sk, struct hci_dev *hdev,
 			       status);
 }
 
-static void read_local_oob_data_complete(struct hci_dev *hdev, void *data, int err)
+static void read_local_oob_data_complete(struct hci_dev *hdev, void *data,
+					 int err)
 {
 	struct mgmt_rp_read_local_oob_data mgmt_rp;
 	size_t rp_size = sizeof(mgmt_rp);
@@ -5502,7 +5561,8 @@ static void read_local_oob_data_complete(struct hci_dev *hdev, void *data, int e
 	bt_dev_dbg(hdev, "status %d", status);
 
 	if (status) {
-		mgmt_cmd_status(cmd->sk, hdev->id, MGMT_OP_READ_LOCAL_OOB_DATA, status);
+		mgmt_cmd_status(cmd->sk, hdev->id, MGMT_OP_READ_LOCAL_OOB_DATA,
+				status);
 		goto remove;
 	}
 
@@ -5784,17 +5844,12 @@ static void start_discovery_complete(struct hci_dev *hdev, void *data, int err)
 
 	bt_dev_dbg(hdev, "err %d", err);
 
-	if (err == -ECANCELED)
-		return;
-
-	if (cmd != pending_find(MGMT_OP_START_DISCOVERY, hdev) &&
-	    cmd != pending_find(MGMT_OP_START_LIMITED_DISCOVERY, hdev) &&
-	    cmd != pending_find(MGMT_OP_START_SERVICE_DISCOVERY, hdev))
+	if (err == -ECANCELED || !mgmt_pending_valid(hdev, cmd, true))
 		return;
 
 	mgmt_cmd_complete(cmd->sk, cmd->hdev->id, cmd->opcode, mgmt_status(err),
 			  cmd->param, 1);
-	mgmt_pending_remove(cmd);
+	mgmt_pending_free(cmd);
 
 	hci_discovery_set_state(hdev, err ? DISCOVERY_STOPPED:
 				DISCOVERY_FINDING);
@@ -5802,6 +5857,9 @@ static void start_discovery_complete(struct hci_dev *hdev, void *data, int err)
 
 static int start_discovery_sync(struct hci_dev *hdev, void *data)
 {
+	if (!mgmt_pending_valid(hdev, data, false))
+		return -ECANCELED;
+
 	return hci_start_discovery_sync(hdev);
 }
 
@@ -6007,15 +6065,14 @@ static void stop_discovery_complete(struct hci_dev *hdev, void *data, int err)
 {
 	struct mgmt_pending_cmd *cmd = data;
 
-	if (err == -ECANCELED ||
-	    cmd != pending_find(MGMT_OP_STOP_DISCOVERY, hdev))
+	if (err == -ECANCELED || !mgmt_pending_valid(hdev, cmd, true))
 		return;
 
 	bt_dev_dbg(hdev, "err %d", err);
 
 	mgmt_cmd_complete(cmd->sk, cmd->hdev->id, cmd->opcode, mgmt_status(err),
 			  cmd->param, 1);
-	mgmt_pending_remove(cmd);
+	mgmt_pending_free(cmd);
 
 	if (!err)
 		hci_discovery_set_state(hdev, DISCOVERY_STOPPED);
@@ -6023,6 +6080,9 @@ static void stop_discovery_complete(struct hci_dev *hdev, void *data, int err)
 
 static int stop_discovery_sync(struct hci_dev *hdev, void *data)
 {
+	if (!mgmt_pending_valid(hdev, data, false))
+		return -ECANCELED;
+
 	return hci_stop_discovery_sync(hdev);
 }
 
@@ -6232,14 +6292,18 @@ static void enable_advertising_instance(struct hci_dev *hdev, int err)
 
 static void set_advertising_complete(struct hci_dev *hdev, void *data, int err)
 {
+	struct mgmt_pending_cmd *cmd = data;
 	struct cmd_lookup match = { NULL, hdev };
 	u8 instance;
 	struct adv_info *adv_instance;
 	u8 status = mgmt_status(err);
 
+	if (err == -ECANCELED || !mgmt_pending_valid(hdev, data, true))
+		return;
+
 	if (status) {
-		mgmt_pending_foreach(MGMT_OP_SET_ADVERTISING, hdev, true,
-				     cmd_status_rsp, &status);
+		mgmt_cmd_status(cmd->sk, cmd->hdev->id, cmd->opcode, status);
+		mgmt_pending_free(cmd);
 		return;
 	}
 
@@ -6248,8 +6312,7 @@ static void set_advertising_complete(struct hci_dev *hdev, void *data, int err)
 	else
 		hci_dev_clear_flag(hdev, HCI_ADVERTISING);
 
-	mgmt_pending_foreach(MGMT_OP_SET_ADVERTISING, hdev, true, settings_rsp,
-			     &match);
+	settings_rsp(cmd, &match);
 
 	new_settings(hdev, match.sk);
 
@@ -6281,8 +6344,14 @@ static void set_advertising_complete(struct hci_dev *hdev, void *data, int err)
 static int set_adv_sync(struct hci_dev *hdev, void *data)
 {
 	struct mgmt_pending_cmd *cmd = data;
-	struct mgmt_mode *cp = cmd->param;
-	u8 val = !!cp->val;
+	struct mgmt_mode *cp;
+	u8 val;
+
+	if (!mgmt_pending_valid(hdev, cmd, false))
+		return -ECANCELED;
+
+	cp = cmd->param;
+	val = !!cp->val;
 
 	if (cp->val == 0x02)
 		hci_dev_set_flag(hdev, HCI_ADVERTISING_CONNECTABLE);
@@ -8037,10 +8106,6 @@ static void read_local_oob_ext_data_complete(struct hci_dev *hdev, void *data,
 	u8 status = mgmt_status(err);
 	u16 eir_len;
 
-	if (err == -ECANCELED ||
-	    cmd != pending_find(MGMT_OP_READ_LOCAL_OOB_EXT_DATA, hdev))
-		return;
-
 	if (!status) {
 		if (!skb)
 			status = MGMT_STATUS_FAILED;
@@ -8147,7 +8212,7 @@ static void read_local_oob_ext_data_complete(struct hci_dev *hdev, void *data,
 		kfree_skb(skb);
 
 	kfree(mgmt_rp);
-	mgmt_pending_remove(cmd);
+	mgmt_pending_free(cmd);
 }
 
 static int read_local_ssp_oob_req(struct hci_dev *hdev, struct sock *sk,
@@ -8156,7 +8221,7 @@ static int read_local_ssp_oob_req(struct hci_dev *hdev, struct sock *sk,
 	struct mgmt_pending_cmd *cmd;
 	int err;
 
-	cmd = mgmt_pending_add(sk, MGMT_OP_READ_LOCAL_OOB_EXT_DATA, hdev,
+	cmd = mgmt_pending_new(sk, MGMT_OP_READ_LOCAL_OOB_EXT_DATA, hdev,
 			       cp, sizeof(*cp));
 	if (!cmd)
 		return -ENOMEM;
diff --git a/net/bluetooth/mgmt_util.c b/net/bluetooth/mgmt_util.c
index a88a07da3947..be6d9b8db51b 100644
--- a/net/bluetooth/mgmt_util.c
+++ b/net/bluetooth/mgmt_util.c
@@ -320,6 +320,29 @@ void mgmt_pending_remove(struct mgmt_pending_cmd *cmd)
 	mgmt_pending_free(cmd);
 }
 
+bool mgmt_pending_valid(struct hci_dev *hdev, struct mgmt_pending_cmd *cmd,
+			bool remove)
+{
+	struct mgmt_pending_cmd *tmp;
+
+	if (!cmd)
+		return false;
+
+	mutex_lock(&hdev->mgmt_pending_lock);
+
+	list_for_each_entry(tmp, &hdev->mgmt_pending, list) {
+		if (cmd == tmp) {
+			if (remove)
+				list_del(&cmd->list);
+			mutex_unlock(&hdev->mgmt_pending_lock);
+			return true;
+		}
+	}
+
+	mutex_unlock(&hdev->mgmt_pending_lock);
+	return false;
+}
+
 void mgmt_mesh_foreach(struct hci_dev *hdev,
 		       void (*cb)(struct mgmt_mesh_tx *mesh_tx, void *data),
 		       void *data, struct sock *sk)
diff --git a/net/bluetooth/mgmt_util.h b/net/bluetooth/mgmt_util.h
index 024e51dd6937..5aeba4c7b07f 100644
--- a/net/bluetooth/mgmt_util.h
+++ b/net/bluetooth/mgmt_util.h
@@ -65,6 +65,8 @@ struct mgmt_pending_cmd *mgmt_pending_new(struct sock *sk, u16 opcode,
 					  void *data, u16 len);
 void mgmt_pending_free(struct mgmt_pending_cmd *cmd);
 void mgmt_pending_remove(struct mgmt_pending_cmd *cmd);
+bool mgmt_pending_valid(struct hci_dev *hdev, struct mgmt_pending_cmd *cmd,
+			bool remove);
 void mgmt_mesh_foreach(struct hci_dev *hdev,
 		       void (*cb)(struct mgmt_mesh_tx *mesh_tx, void *data),
 		       void *data, struct sock *sk);
-- 
2.51.0

Re: [PATCH v6 3/3] Bluetooth: MGMT: Fix possible UAFs

[Pauli Virtanen]

Hi,

ma, 2025-09-15 kello 12:15 -0400, Luiz Augusto von Dentz kirjoitti:
> From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
> 
> This attemps to fix possible UAFs caused by struct mgmt_pending being
> freed while still being processed like in the following trace, in order
> to fix mgmt_pending_valid is introduce and use to check if the
> mgmt_pending hasn't been removed from the pending list, on the complete
> callbacks it is used to check and in addtion remove the cmd from the list
> while holding mgmt_pending_lock to avoid TOCTOU problems since if the cmd
> is left on the list it can still be accessed and freed.
> 
> BUG: KASAN: slab-use-after-free in mgmt_add_adv_patterns_monitor_sync+0x35/0x50 net/bluetooth/mgmt.c:5223
> Read of size 8 at addr ffff8880709d4dc0 by task kworker/u11:0/55
> 
> CPU: 0 UID: 0 PID: 55 Comm: kworker/u11:0 Not tainted 6.16.4 #2 PREEMPT(full)
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
> Workqueue: hci0 hci_cmd_sync_work
> Call Trace:
>  <TASK>
>  dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
>  print_address_description mm/kasan/report.c:378 [inline]
>  print_report+0xca/0x240 mm/kasan/report.c:482
>  kasan_report+0x118/0x150 mm/kasan/report.c:595
>  mgmt_add_adv_patterns_monitor_sync+0x35/0x50 net/bluetooth/mgmt.c:5223
>  hci_cmd_sync_work+0x210/0x3a0 net/bluetooth/hci_sync.c:332
>  process_one_work kernel/workqueue.c:3238 [inline]
>  process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321
[clip]
> diff --git a/net/bluetooth/mgmt_util.c b/net/bluetooth/mgmt_util.c
> index a88a07da3947..be6d9b8db51b 100644
> --- a/net/bluetooth/mgmt_util.c
> +++ b/net/bluetooth/mgmt_util.c
> @@ -320,6 +320,29 @@ void mgmt_pending_remove(struct mgmt_pending_cmd *cmd)
>  	mgmt_pending_free(cmd);
>  }
>  
> +bool mgmt_pending_valid(struct hci_dev *hdev, struct mgmt_pending_cmd *cmd,
> +			bool remove)
> +{
> +	struct mgmt_pending_cmd *tmp;
> +
> +	if (!cmd)
> +		return false;
> +
> +	mutex_lock(&hdev->mgmt_pending_lock);
> +
> +	list_for_each_entry(tmp, &hdev->mgmt_pending, list) {
> +		if (cmd == tmp) {
> +			if (remove)
> +				list_del(&cmd->list);
> +			mutex_unlock(&hdev->mgmt_pending_lock);
> +			return true;

There seems to be a theoretical UAF left:

Task 1: [in mgmt_pending_foreach, remove=true] mutex_lock()

Task 2: [in here, remove=false] mutex_unlock()

Task 1: mgmt_pending_free(cmd)

Task 2: return true

mgmt_pending_valid(hdev, cmd, false) returns true even though cmd is
already freed.

This function could leave locking to caller and have
lockdep_assert_held(&hdev->mgmt_pending_lock). 

Or maybe always remove=true, and caller has to add it back to the list
if needed.

> +		}
> +	}
> +
> +	mutex_unlock(&hdev->mgmt_pending_lock);
> +	return false;
> +}
> +
>  void mgmt_mesh_foreach(struct hci_dev *hdev,
>  		       void (*cb)(struct mgmt_mesh_tx *mesh_tx, void *data),
>  		       void *data, struct sock *sk)
> diff --git a/net/bluetooth/mgmt_util.h b/net/bluetooth/mgmt_util.h
> index 024e51dd6937..5aeba4c7b07f 100644
> --- a/net/bluetooth/mgmt_util.h
> +++ b/net/bluetooth/mgmt_util.h
> @@ -65,6 +65,8 @@ struct mgmt_pending_cmd *mgmt_pending_new(struct sock *sk, u16 opcode,
>  					  void *data, u16 len);
>  void mgmt_pending_free(struct mgmt_pending_cmd *cmd);
>  void mgmt_pending_remove(struct mgmt_pending_cmd *cmd);
> +bool mgmt_pending_valid(struct hci_dev *hdev, struct mgmt_pending_cmd *cmd,
> +			bool remove);
>  void mgmt_mesh_foreach(struct hci_dev *hdev,
>  		       void (*cb)(struct mgmt_mesh_tx *mesh_tx, void *data),
>  		       void *data, struct sock *sk);

-- 
Pauli Virtanen

Re: [PATCH v6 3/3] Bluetooth: MGMT: Fix possible UAFs

[Luiz Augusto von Dentz]

Hi Pauli,

On Tue, Sep 16, 2025 at 12:37 PM Pauli Virtanen <pav@iki.fi> wrote:
>
> Hi,
>
> ma, 2025-09-15 kello 12:15 -0400, Luiz Augusto von Dentz kirjoitti:
> > From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
> >
> > This attemps to fix possible UAFs caused by struct mgmt_pending being
> > freed while still being processed like in the following trace, in order
> > to fix mgmt_pending_valid is introduce and use to check if the
> > mgmt_pending hasn't been removed from the pending list, on the complete
> > callbacks it is used to check and in addtion remove the cmd from the list
> > while holding mgmt_pending_lock to avoid TOCTOU problems since if the cmd
> > is left on the list it can still be accessed and freed.
> >
> > BUG: KASAN: slab-use-after-free in mgmt_add_adv_patterns_monitor_sync+0x35/0x50 net/bluetooth/mgmt.c:5223
> > Read of size 8 at addr ffff8880709d4dc0 by task kworker/u11:0/55
> >
> > CPU: 0 UID: 0 PID: 55 Comm: kworker/u11:0 Not tainted 6.16.4 #2 PREEMPT(full)
> > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
> > Workqueue: hci0 hci_cmd_sync_work
> > Call Trace:
> >  <TASK>
> >  dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
> >  print_address_description mm/kasan/report.c:378 [inline]
> >  print_report+0xca/0x240 mm/kasan/report.c:482
> >  kasan_report+0x118/0x150 mm/kasan/report.c:595
> >  mgmt_add_adv_patterns_monitor_sync+0x35/0x50 net/bluetooth/mgmt.c:5223
> >  hci_cmd_sync_work+0x210/0x3a0 net/bluetooth/hci_sync.c:332
> >  process_one_work kernel/workqueue.c:3238 [inline]
> >  process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321
> [clip]
> > diff --git a/net/bluetooth/mgmt_util.c b/net/bluetooth/mgmt_util.c
> > index a88a07da3947..be6d9b8db51b 100644
> > --- a/net/bluetooth/mgmt_util.c
> > +++ b/net/bluetooth/mgmt_util.c
> > @@ -320,6 +320,29 @@ void mgmt_pending_remove(struct mgmt_pending_cmd *cmd)
> >       mgmt_pending_free(cmd);
> >  }
> >
> > +bool mgmt_pending_valid(struct hci_dev *hdev, struct mgmt_pending_cmd *cmd,
> > +                     bool remove)
> > +{
> > +     struct mgmt_pending_cmd *tmp;
> > +
> > +     if (!cmd)
> > +             return false;
> > +
> > +     mutex_lock(&hdev->mgmt_pending_lock);
> > +
> > +     list_for_each_entry(tmp, &hdev->mgmt_pending, list) {
> > +             if (cmd == tmp) {
> > +                     if (remove)
> > +                             list_del(&cmd->list);
> > +                     mutex_unlock(&hdev->mgmt_pending_lock);
> > +                     return true;
>
> There seems to be a theoretical UAF left:
>
> Task 1: [in mgmt_pending_foreach, remove=true] mutex_lock()
>
> Task 2: [in here, remove=false] mutex_unlock()
>
> Task 1: mgmt_pending_free(cmd)
>
> Task 2: return true
>
> mgmt_pending_valid(hdev, cmd, false) returns true even though cmd is
> already freed.

You mean that after it has unlocked it still has the TOCTOU problem, right?

> This function could leave locking to caller and have
> lockdep_assert_held(&hdev->mgmt_pending_lock).
>
> Or maybe always remove=true, and caller has to add it back to the list
> if needed.

Yeah, well then perhaps we need an alternative version to
mgmt_pending_valid which can be called while holding
mgmt_pending_lock, that said there is another thing that we might want
to fix as well.

> > +             }
> > +     }
> > +
> > +     mutex_unlock(&hdev->mgmt_pending_lock);
> > +     return false;
> > +}
> > +
> >  void mgmt_mesh_foreach(struct hci_dev *hdev,
> >                      void (*cb)(struct mgmt_mesh_tx *mesh_tx, void *data),
> >                      void *data, struct sock *sk)
> > diff --git a/net/bluetooth/mgmt_util.h b/net/bluetooth/mgmt_util.h
> > index 024e51dd6937..5aeba4c7b07f 100644
> > --- a/net/bluetooth/mgmt_util.h
> > +++ b/net/bluetooth/mgmt_util.h
> > @@ -65,6 +65,8 @@ struct mgmt_pending_cmd *mgmt_pending_new(struct sock *sk, u16 opcode,
> >                                         void *data, u16 len);
> >  void mgmt_pending_free(struct mgmt_pending_cmd *cmd);
> >  void mgmt_pending_remove(struct mgmt_pending_cmd *cmd);
> > +bool mgmt_pending_valid(struct hci_dev *hdev, struct mgmt_pending_cmd *cmd,
> > +                     bool remove);
> >  void mgmt_mesh_foreach(struct hci_dev *hdev,
> >                      void (*cb)(struct mgmt_mesh_tx *mesh_tx, void *data),
> >                      void *data, struct sock *sk);
>
> --
> Pauli Virtanen



-- 
Luiz Augusto von Dentz

Re: [PATCH v6 1/3] Bluetooth: hci_event: Fix UAF in hci_conn_tx_dequeue

[patchwork-bot+bluetooth]

Hello:

This series was applied to bluetooth/bluetooth-next.git (master)
by Luiz Augusto von Dentz <luiz.von.dentz@intel.com>:

On Mon, 15 Sep 2025 12:15:02 -0400 you wrote:
> From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
> 
> This fixes the following UAF caused by not properly locking hdev when
> processing HCI_EV_NUM_COMP_PKTS:
> 
> BUG: KASAN: slab-use-after-free in hci_conn_tx_dequeue+0x1be/0x220 net/bluetooth/hci_conn.c:3036
> Read of size 4 at addr ffff8880740f0940 by task kworker/u11:0/54
> 
> [...]

Here is the summary with links:
  - [v6,1/3] Bluetooth: hci_event: Fix UAF in hci_conn_tx_dequeue
    https://git.kernel.org/bluetooth/bluetooth-next/c/6b74ce021062
  - [v6,2/3] Bluetooth: hci_event: Fix UAF in hci_acl_create_conn_sync
    https://git.kernel.org/bluetooth/bluetooth-next/c/b6018d6825ce
  - [v6,3/3] Bluetooth: MGMT: Fix possible UAFs
    https://git.kernel.org/bluetooth/bluetooth-next/c/3fe1be6fee6e

You are awesome, thank you!
-- 
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