Dear Luiz,
Thank you for your patch.
Am 10.09.25 um 00:03 schrieb Luiz Augusto von Dentz:
From: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx>
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@xxxxxxxxxxx>
Use Junvy Yang <…>?
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx>
---
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.
*/
Reviewed-by: Paul Menzel <pmenzel@xxxxxxxxxxxxx>
Kind regards,
Paul
