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authorLuiz Augusto von Dentz <luiz.von.dentz@intel.com>2023-08-09 16:49:33 -0700
committerLuiz Augusto von Dentz <luiz.von.dentz@intel.com>2023-08-24 12:19:55 -0700
commit94d9ba9f9888b748d4abd2aa1547af56ae85f772 (patch)
tree911c4e4954d16c62b5407d121382039bb8b040fd /net/bluetooth
parent491f9eff276012f3036f5546198cdf4a9e268284 (diff)
Bluetooth: hci_sync: Fix UAF in hci_disconnect_all_sync
Use-after-free can occur in hci_disconnect_all_sync if a connection is deleted by concurrent processing of a controller event. To prevent this the code now tries to iterate over the list backwards to ensure the links are cleanup before its parents, also it no longer relies on a cursor, instead it always uses the last element since hci_abort_conn_sync is guaranteed to call hci_conn_del. UAF crash log: ================================================================== BUG: KASAN: slab-use-after-free in hci_set_powered_sync (net/bluetooth/hci_sync.c:5424) [bluetooth] Read of size 8 at addr ffff888009d9c000 by task kworker/u9:0/124 CPU: 0 PID: 124 Comm: kworker/u9:0 Tainted: G W 6.5.0-rc1+ #10 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-1.fc38 04/01/2014 Workqueue: hci0 hci_cmd_sync_work [bluetooth] Call Trace: <TASK> dump_stack_lvl+0x5b/0x90 print_report+0xcf/0x670 ? __virt_addr_valid+0xdd/0x160 ? hci_set_powered_sync+0x2c9/0x4a0 [bluetooth] kasan_report+0xa6/0xe0 ? hci_set_powered_sync+0x2c9/0x4a0 [bluetooth] ? __pfx_set_powered_sync+0x10/0x10 [bluetooth] hci_set_powered_sync+0x2c9/0x4a0 [bluetooth] ? __pfx_hci_set_powered_sync+0x10/0x10 [bluetooth] ? __pfx_lock_release+0x10/0x10 ? __pfx_set_powered_sync+0x10/0x10 [bluetooth] hci_cmd_sync_work+0x137/0x220 [bluetooth] process_one_work+0x526/0x9d0 ? __pfx_process_one_work+0x10/0x10 ? __pfx_do_raw_spin_lock+0x10/0x10 ? mark_held_locks+0x1a/0x90 worker_thread+0x92/0x630 ? __pfx_worker_thread+0x10/0x10 kthread+0x196/0x1e0 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x2c/0x50 </TASK> Allocated by task 1782: kasan_save_stack+0x33/0x60 kasan_set_track+0x25/0x30 __kasan_kmalloc+0x8f/0xa0 hci_conn_add+0xa5/0xa80 [bluetooth] hci_bind_cis+0x881/0x9b0 [bluetooth] iso_connect_cis+0x121/0x520 [bluetooth] iso_sock_connect+0x3f6/0x790 [bluetooth] __sys_connect+0x109/0x130 __x64_sys_connect+0x40/0x50 do_syscall_64+0x60/0x90 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 Freed by task 695: kasan_save_stack+0x33/0x60 kasan_set_track+0x25/0x30 kasan_save_free_info+0x2b/0x50 __kasan_slab_free+0x10a/0x180 __kmem_cache_free+0x14d/0x2e0 device_release+0x5d/0xf0 kobject_put+0xdf/0x270 hci_disconn_complete_evt+0x274/0x3a0 [bluetooth] hci_event_packet+0x579/0x7e0 [bluetooth] hci_rx_work+0x287/0xaa0 [bluetooth] process_one_work+0x526/0x9d0 worker_thread+0x92/0x630 kthread+0x196/0x1e0 ret_from_fork+0x2c/0x50 ================================================================== Fixes: 182ee45da083 ("Bluetooth: hci_sync: Rework hci_suspend_notifier") Signed-off-by: Pauli Virtanen <pav@iki.fi> Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Diffstat (limited to 'net/bluetooth')
-rw-r--r--net/bluetooth/hci_sync.c55
1 files changed, 35 insertions, 20 deletions
diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
index 5eb30ba21370..d10a0f36b947 100644
--- a/net/bluetooth/hci_sync.c
+++ b/net/bluetooth/hci_sync.c
@@ -5370,6 +5370,7 @@ int hci_abort_conn_sync(struct hci_dev *hdev, struct hci_conn *conn, u8 reason)
{
int err = 0;
u16 handle = conn->handle;
+ struct hci_conn *c;
switch (conn->state) {
case BT_CONNECTED:
@@ -5389,43 +5390,57 @@ int hci_abort_conn_sync(struct hci_dev *hdev, struct hci_conn *conn, u8 reason)
hci_dev_unlock(hdev);
return 0;
default:
+ hci_dev_lock(hdev);
conn->state = BT_CLOSED;
+ hci_disconn_cfm(conn, reason);
+ hci_conn_del(conn);
+ hci_dev_unlock(hdev);
return 0;
}
+ hci_dev_lock(hdev);
+
+ /* Check if the connection hasn't been cleanup while waiting
+ * commands to complete.
+ */
+ c = hci_conn_hash_lookup_handle(hdev, handle);
+ if (!c || c != conn) {
+ err = 0;
+ goto unlock;
+ }
+
/* Cleanup hci_conn object if it cannot be cancelled as it
* likelly means the controller and host stack are out of sync
* or in case of LE it was still scanning so it can be cleanup
* safely.
*/
- if (err) {
- struct hci_conn *c;
-
- /* Check if the connection hasn't been cleanup while waiting
- * commands to complete.
- */
- c = hci_conn_hash_lookup_handle(hdev, handle);
- if (!c || c != conn)
- return 0;
-
- hci_dev_lock(hdev);
- hci_conn_failed(conn, err);
- hci_dev_unlock(hdev);
- }
+ hci_conn_failed(conn, reason);
+unlock:
+ hci_dev_unlock(hdev);
return err;
}
static int hci_disconnect_all_sync(struct hci_dev *hdev, u8 reason)
{
- struct hci_conn *conn, *tmp;
- int err;
+ struct list_head *head = &hdev->conn_hash.list;
+ struct hci_conn *conn;
- list_for_each_entry_safe(conn, tmp, &hdev->conn_hash.list, list) {
- err = hci_abort_conn_sync(hdev, conn, reason);
- if (err)
- return err;
+ rcu_read_lock();
+ while ((conn = list_first_or_null_rcu(head, struct hci_conn, list))) {
+ /* Make sure the connection is not freed while unlocking */
+ conn = hci_conn_get(conn);
+ rcu_read_unlock();
+ /* Disregard possible errors since hci_conn_del shall have been
+ * called even in case of errors had occurred since it would
+ * then cause hci_conn_failed to be called which calls
+ * hci_conn_del internally.
+ */
+ hci_abort_conn_sync(hdev, conn, reason);
+ hci_conn_put(conn);
+ rcu_read_lock();
}
+ rcu_read_unlock();
return 0;
}