From 3d1c16e920c88eb5e583e1b4a10b95a5dc97ec22 Mon Sep 17 00:00:00 2001 From: Luiz Augusto von Dentz Date: Fri, 8 Mar 2024 11:02:48 -0500 Subject: [PATCH] Bluetooth: hci_sync: Fix UAF in hci_acl_create_conn_sync This fixes the following error caused by hci_conn being freed while hcy_acl_create_conn_sync is pending: ================================================================== BUG: KASAN: slab-use-after-free in hci_acl_create_conn_sync+0xa7/0x2e0 Write of size 2 at addr ffff888002ae0036 by task kworker/u3:0/848 CPU: 0 PID: 848 Comm: kworker/u3:0 Not tainted 6.8.0-rc6-g2ab3e8d67fc1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-1.fc38 04/01/2014 Workqueue: hci0 hci_cmd_sync_work Call Trace: dump_stack_lvl+0x21/0x70 print_report+0xce/0x620 ? preempt_count_sub+0x13/0xc0 ? __virt_addr_valid+0x15f/0x310 ? hci_acl_create_conn_sync+0xa7/0x2e0 kasan_report+0xdf/0x110 ? hci_acl_create_conn_sync+0xa7/0x2e0 hci_acl_create_conn_sync+0xa7/0x2e0 ? __pfx_hci_acl_create_conn_sync+0x10/0x10 ? __pfx_lock_release+0x10/0x10 ? __pfx_hci_acl_create_conn_sync+0x10/0x10 hci_cmd_sync_work+0x138/0x1c0 process_one_work+0x405/0x800 ? __pfx_lock_acquire+0x10/0x10 ? __pfx_process_one_work+0x10/0x10 worker_thread+0x37b/0x670 ? __pfx_worker_thread+0x10/0x10 kthread+0x19b/0x1e0 ? kthread+0xfe/0x1e0 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x2f/0x50 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 Allocated by task 847: kasan_save_stack+0x33/0x60 kasan_save_track+0x14/0x30 __kasan_kmalloc+0x8f/0xa0 hci_conn_add+0xc6/0x970 hci_connect_acl+0x309/0x410 pair_device+0x4fb/0x710 hci_sock_sendmsg+0x933/0xef0 sock_write_iter+0x2c3/0x2d0 do_iter_readv_writev+0x21a/0x2e0 vfs_writev+0x21c/0x7b0 do_writev+0x14a/0x180 do_syscall_64+0x77/0x150 entry_SYSCALL_64_after_hwframe+0x6c/0x74 Freed by task 847: kasan_save_stack+0x33/0x60 kasan_save_track+0x14/0x30 kasan_save_free_info+0x3b/0x60 __kasan_slab_free+0xfa/0x150 kfree+0xcb/0x250 device_release+0x58/0xf0 kobject_put+0xbb/0x160 hci_conn_del+0x281/0x570 hci_conn_hash_flush+0xfc/0x130 hci_dev_close_sync+0x336/0x960 hci_dev_close+0x10e/0x140 hci_sock_ioctl+0x14a/0x5c0 sock_ioctl+0x58a/0x5d0 __x64_sys_ioctl+0x480/0xf60 do_syscall_64+0x77/0x150 entry_SYSCALL_64_after_hwframe+0x6c/0x74 Fixes: 45340097ce6e ("Bluetooth: hci_conn: Only do ACL connections sequentially") Signed-off-by: Luiz Augusto von Dentz --- net/bluetooth/hci_sync.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c index 8a3d0d1f7871..f6b662369322 100644 --- a/net/bluetooth/hci_sync.c +++ b/net/bluetooth/hci_sync.c @@ -6709,6 +6709,9 @@ static int hci_acl_create_conn_sync(struct hci_dev *hdev, void *data) struct hci_cp_create_conn cp; int err; + if (!hci_conn_valid(hdev, conn)) + return -ECANCELED; + /* Many controllers disallow HCI Create Connection while it is doing * HCI Inquiry. So we cancel the Inquiry first before issuing HCI Create * Connection. This may cause the MGMT discovering state to become false