From 5c4c8c9544099bb9043a10a5318130a943e32fc3 Mon Sep 17 00:00:00 2001

From: Archie Pusaka <apusaka@chromium.org>

Date: Mon, 22 Mar 2021 14:03:11 +0800

Subject: [PATCH] Bluetooth: verify AMP hci_chan before amp_destroy

Git-commit: 5c4c8c9544099bb9043a10a5318130a943e32fc3

Patch-mainline: v5.13-rc1

References: CVE-2021-33034 bsc#1186111

hci_chan can be created in 2 places: hci_loglink_complete_evt() if

it is an AMP hci_chan, or l2cap_conn_add() otherwise. In theory,

Only AMP hci_chan should be removed by a call to

hci_disconn_loglink_complete_evt(). However, the controller might mess

up, call that function, and destroy an hci_chan which is not initiated

by hci_loglink_complete_evt().

This patch adds a verification that the destroyed hci_chan must have

been init'd by hci_loglink_complete_evt().

Example crash call trace:

Call Trace:

 __dump_stack lib/dump_stack.c:77 [inline]

 dump_stack+0xe3/0x144 lib/dump_stack.c:118

 print_address_description+0x67/0x22a mm/kasan/report.c:256

 kasan_report_error mm/kasan/report.c:354 [inline]

 kasan_report mm/kasan/report.c:412 [inline]

 kasan_report+0x251/0x28f mm/kasan/report.c:396

 hci_send_acl+0x3b/0x56e net/bluetooth/hci_core.c:4072

 l2cap_send_cmd+0x5af/0x5c2 net/bluetooth/l2cap_core.c:877

 l2cap_send_move_chan_cfm_icid+0x8e/0xb1 net/bluetooth/l2cap_core.c:4661

 l2cap_move_fail net/bluetooth/l2cap_core.c:5146 [inline]

 l2cap_move_channel_rsp net/bluetooth/l2cap_core.c:5185 [inline]

 l2cap_bredr_sig_cmd net/bluetooth/l2cap_core.c:5464 [inline]

 l2cap_sig_channel net/bluetooth/l2cap_core.c:5799 [inline]

 l2cap_recv_frame+0x1d12/0x51aa net/bluetooth/l2cap_core.c:7023

 l2cap_recv_acldata+0x2ea/0x693 net/bluetooth/l2cap_core.c:7596

 hci_acldata_packet net/bluetooth/hci_core.c:4606 [inline]

 hci_rx_work+0x2bd/0x45e net/bluetooth/hci_core.c:4796

 process_one_work+0x6f8/0xb50 kernel/workqueue.c:2175

 worker_thread+0x4fc/0x670 kernel/workqueue.c:2321

 kthread+0x2f0/0x304 kernel/kthread.c:253

 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:415

Allocated by task 38:

 set_track mm/kasan/kasan.c:460 [inline]

 kasan_kmalloc+0x8d/0x9a mm/kasan/kasan.c:553

 kmem_cache_alloc_trace+0x102/0x129 mm/slub.c:2787

 kmalloc include/linux/slab.h:515 [inline]

 kzalloc include/linux/slab.h:709 [inline]

 hci_chan_create+0x86/0x26d net/bluetooth/hci_conn.c:1674

 l2cap_conn_add.part.0+0x1c/0x814 net/bluetooth/l2cap_core.c:7062

 l2cap_conn_add net/bluetooth/l2cap_core.c:7059 [inline]

 l2cap_connect_cfm+0x134/0x852 net/bluetooth/l2cap_core.c:7381

 hci_connect_cfm+0x9d/0x122 include/net/bluetooth/hci_core.h:1404

 hci_remote_ext_features_evt net/bluetooth/hci_event.c:4161 [inline]

 hci_event_packet+0x463f/0x72fa net/bluetooth/hci_event.c:5981

 hci_rx_work+0x197/0x45e net/bluetooth/hci_core.c:4791

 process_one_work+0x6f8/0xb50 kernel/workqueue.c:2175

 worker_thread+0x4fc/0x670 kernel/workqueue.c:2321

 kthread+0x2f0/0x304 kernel/kthread.c:253

 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:415

Freed by task 1732:

 set_track mm/kasan/kasan.c:460 [inline]

 __kasan_slab_free mm/kasan/kasan.c:521 [inline]

 __kasan_slab_free+0x106/0x128 mm/kasan/kasan.c:493

 slab_free_hook mm/slub.c:1409 [inline]

 slab_free_freelist_hook+0xaa/0xf6 mm/slub.c:1436

 slab_free mm/slub.c:3009 [inline]

 kfree+0x182/0x21e mm/slub.c:3972

 hci_disconn_loglink_complete_evt net/bluetooth/hci_event.c:4891 [inline]

 hci_event_packet+0x6a1c/0x72fa net/bluetooth/hci_event.c:6050

 hci_rx_work+0x197/0x45e net/bluetooth/hci_core.c:4791

 process_one_work+0x6f8/0xb50 kernel/workqueue.c:2175

 worker_thread+0x4fc/0x670 kernel/workqueue.c:2321

 kthread+0x2f0/0x304 kernel/kthread.c:253

 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:415

The buggy address belongs to the object at ffff8881d7af9180

 which belongs to the cache kmalloc-128 of size 128

The buggy address is located 24 bytes inside of

 128-byte region [ffff8881d7af9180, ffff8881d7af9200)

The buggy address belongs to the page:

page:ffffea00075ebe40 count:1 mapcount:0 mapping:ffff8881da403200 index:0x0

Flags: 0x8000000000000200(slab)

Raw: 8000000000000200 dead000000000100 dead000000000200 ffff8881da403200

Raw: 0000000000000000 0000000080150015 00000001ffffffff 0000000000000000

page dumped because: kasan: bad access detected

Memory state around the buggy address:

 ffff8881d7af9080: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb

 ffff8881d7af9100: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc

>ffff8881d7af9180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb                            ^ ffff8881d7af9200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8881d7af9280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc

Signed-off-by: Archie Pusaka <apusaka@chromium.org>

Reported-by: syzbot+98228e7407314d2d4ba2@syzkaller.appspotmail.com

Reviewed-by: Alain Michaud <alainm@chromium.org>

Reviewed-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

Acked-by: Takashi Iwai <tiwai@suse.de>

---

 include/net/bluetooth/hci_core.h | 1 +

 net/bluetooth/hci_event.c        | 3 ++-

 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h

index ebdd4afe30d2..ca4ac6603b9a 100644

--- a/include/net/bluetooth/hci_core.h

+++ b/include/net/bluetooth/hci_core.h

@@ -704,6 +704,7 @@ struct hci_chan {

 	struct sk_buff_head data_q;

 	unsigned int	sent;

 	__u8		state;

+	bool		amp;

 };

 struct hci_conn_params {

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c

index cf2f4a0abdbd..341c8ce93648 100644

--- a/net/bluetooth/hci_event.c

+++ b/net/bluetooth/hci_event.c

@@ -5032,6 +5032,7 @@ static void hci_loglink_complete_evt(struct hci_dev *hdev, struct sk_buff *skb)

 		return;

 	hchan->handle = le16_to_cpu(ev->handle);

+	hchan->amp = true;

 	BT_DBG("hcon %p mgr %p hchan %p", hcon, hcon->amp_mgr, hchan);

@@ -5064,7 +5065,7 @@ static void hci_disconn_loglink_complete_evt(struct hci_dev *hdev,

 	hci_dev_lock(hdev);

 	hchan = hci_chan_lookup_handle(hdev, le16_to_cpu(ev->handle));

-	if (!hchan)

+	if (!hchan || !hchan->amp)

 		goto unlock;

 	amp_destroy_logical_link(hchan, ev->reason);

-- 

2.26.2