[PATCH 4.19 286/338] Bluetooth: Fix use after free in hci_send_acl

Greg Kroah-Hartman
2022-04-14T14:02:00Z

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

[ Upstream commit f63d24baff787e13b723d86fe036f84bdbc35045 ]

This fixes the following trace caused by receiving
HCI_EV_DISCONN_PHY_LINK_COMPLETE which does call hci_conn_del without
first checking if conn->type is in fact AMP_LINK and in case it is
do properly cleanup upper layers with hci_disconn_cfm:

==================================================================
BUG: KASAN: use-after-free in hci_send_acl+0xaba/0xc50
Read of size 8 at addr ffff88800e404818 by task bluetoothd/142

CPU: 0 PID: 142 Comm: bluetoothd Not tainted
5.17.0-rc5-00006-gda4022eeac1a #7
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x45/0x59
print_address_description.constprop.0+0x1f/0x150
kasan_report.cold+0x7f/0x11b
hci_send_acl+0xaba/0xc50
l2cap_do_send+0x23f/0x3d0
l2cap_chan_send+0xc06/0x2cc0
l2cap_sock_sendmsg+0x201/0x2b0
sock_sendmsg+0xdc/0x110
sock_write_iter+0x20f/0x370
do_iter_readv_writev+0x343/0x690
do_iter_write+0x132/0x640
vfs_writev+0x198/0x570
do_writev+0x202/0x280
do_syscall_64+0x38/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
RSP: 002b:00007ffce8a099b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
Code: 0f 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b8 0f 1f 00 f3
0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 14 00 00 00 0f 05
<48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 89 54 24 1c 48 89 74 24 10
RDX: 0000000000000001 RSI: 00007ffce8a099e0 RDI: 0000000000000015
RAX: ffffffffffffffda RBX: 00007ffce8a099e0 RCX: 00007f788fc3cf77
R10: 00007ffce8af7080 R11: 0000000000000246 R12: 000055e4ccf75580
RBP: 0000000000000015 R08: 0000000000000002 R09: 0000000000000001
</TASK>
R13: 000055e4ccf754a0 R14: 000055e4ccf75cd0 R15: 000055e4ccf4a6b0

Allocated by task 45:
kasan_save_stack+0x1e/0x40
__kasan_kmalloc+0x81/0xa0
hci_chan_create+0x9a/0x2f0
l2cap_conn_add.part.0+0x1a/0xdc0
l2cap_connect_cfm+0x236/0x1000
le_conn_complete_evt+0x15a7/0x1db0
hci_le_conn_complete_evt+0x226/0x2c0
hci_le_meta_evt+0x247/0x450
hci_event_packet+0x61b/0xe90
hci_rx_work+0x4d5/0xc50
process_one_work+0x8fb/0x15a0
worker_thread+0x576/0x1240
kthread+0x29d/0x340
ret_from_fork+0x1f/0x30

Freed by task 45:
kasan_save_stack+0x1e/0x40
kasan_set_track+0x21/0x30
kasan_set_free_info+0x20/0x30
__kasan_slab_free+0xfb/0x130
kfree+0xac/0x350
hci_conn_cleanup+0x101/0x6a0
hci_conn_del+0x27e/0x6c0
hci_disconn_phylink_complete_evt+0xe0/0x120
hci_event_packet+0x812/0xe90
hci_rx_work+0x4d5/0xc50
process_one_work+0x8fb/0x15a0
worker_thread+0x576/0x1240
kthread+0x29d/0x340
ret_from_fork+0x1f/0x30

The buggy address belongs to the object at ffff88800c0f0500
The buggy address is located 24 bytes inside of
which belongs to the cache kmalloc-128 of size 128
The buggy address belongs to the page:
128-byte region [ffff88800c0f0500, ffff88800c0f0580)
flags: 0x100000000000200(slab|node=0|zone=1)
page:00000000fe45cd86 refcount:1 mapcount:0
mapping:0000000000000000 index:0x0 pfn:0xc0f0
raw: 0000000000000000 0000000080100010 00000001ffffffff
0000000000000000
raw: 0100000000000200 ffffea00003a2c80 dead000000000004
ffff8880078418c0
page dumped because: kasan: bad access detected
ffff88800c0f0400: 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc
Memory state around the buggy address:
>ffff88800c0f0500: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88800c0f0480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88800c0f0580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
==================================================================
ffff88800c0f0600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

Reported-by: Sönke Huster <soenke.huster@eknoes.de>
Tested-by: Sönke Huster <soenke.huster@eknoes.de>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/bluetooth/hci_event.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 196d0d832007..dd7bf437d88e 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -4792,8 +4792,9 @@ static void hci_disconn_phylink_complete_evt(struct hci_dev *hdev,
hci_dev_lock(hdev);

hcon = hci_conn_hash_lookup_handle(hdev, ev->phy_handle);
- if (hcon) {
+ if (hcon && hcon->type == AMP_LINK) {
hcon->state = BT_CLOSED;
+ hci_disconn_cfm(hcon, ev->reason);
hci_conn_del(hcon);
}

--
2.35.1