[PATCH 5.15 150/230] Bluetooth: btmtksdio: fix use-after-free at btmtksdio_recv_event

Greg Kroah-Hartman
2022-07-11T09:55:30Z

From: Sean Wang <sean.wang@mediatek.com>

[ Upstream commit 0fab6361c4ba17d1b43a991bef4238a3c1754d35 ]

We should not access skb buffer data anymore after hci_recv_frame was
called.

[ 39.634809] BUG: KASAN: use-after-free in btmtksdio_recv_event+0x1b0
[ 39.634855] Read of size 1 at addr ffffff80cf28a60d by task kworker
[ 39.634962] Call trace:
[ 39.634974] dump_backtrace+0x0/0x3b8
[ 39.634999] show_stack+0x20/0x2c
[ 39.635016] dump_stack_lvl+0x60/0x78
[ 39.635040] print_address_description+0x70/0x2f0
[ 39.635062] kasan_report+0x154/0x194
[ 39.635079] __asan_report_load1_noabort+0x44/0x50
[ 39.635099] btmtksdio_recv_event+0x1b0/0x1c4
[ 39.635129] btmtksdio_txrx_work+0x6cc/0xac4
[ 39.635157] process_one_work+0x560/0xc5c
[ 39.635177] worker_thread+0x7ec/0xcc0
[ 39.635195] kthread+0x2d0/0x3d0
[ 39.635215] ret_from_fork+0x10/0x20
[ 39.635247] Allocated by task 0:
[ 39.635260] (stack is not available)
[ 39.635281] Freed by task 2392:
[ 39.635295] kasan_save_stack+0x38/0x68
[ 39.635319] kasan_set_track+0x28/0x3c
[ 39.635338] kasan_set_free_info+0x28/0x4c
[ 39.635357] ____kasan_slab_free+0x104/0x150
[ 39.635374] __kasan_slab_free+0x18/0x28
[ 39.635391] slab_free_freelist_hook+0x114/0x248
[ 39.635410] kfree+0xf8/0x2b4
[ 39.635427] skb_free_head+0x58/0x98
[ 39.635447] skb_release_data+0x2f4/0x410
[ 39.635464] skb_release_all+0x50/0x60
[ 39.635481] kfree_skb+0xc8/0x25c
[ 39.635498] hci_event_packet+0x894/0xca4 [bluetooth]
[ 39.635721] hci_rx_work+0x1c8/0x68c [bluetooth]
[ 39.635925] process_one_work+0x560/0xc5c
[ 39.635951] worker_thread+0x7ec/0xcc0
[ 39.635970] kthread+0x2d0/0x3d0
[ 39.635990] ret_from_fork+0x10/0x20
[ 39.636021] The buggy address belongs to the object at ffffff80cf28a600
which belongs to the cache kmalloc-512 of size 512
[ 39.636039] The buggy address is located 13 bytes inside of
512-byte region [ffffff80cf28a600, ffffff80cf28a800)

Fixes: 9aebfd4a2200 ("Bluetooth: mediatek: add support for MediaTek MT7663S and MT7668S SDIO devices")
Co-developed-by: Yake Yang <yake.yang@mediatek.com>
Signed-off-by: Yake Yang <yake.yang@mediatek.com>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/bluetooth/btmtksdio.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/bluetooth/btmtksdio.c b/drivers/bluetooth/btmtksdio.c
index ff1f5dfbb6db..d66e4df171d2 100644
--- a/drivers/bluetooth/btmtksdio.c
+++ b/drivers/bluetooth/btmtksdio.c
@@ -331,6 +331,7 @@ static int btmtksdio_recv_event(struct hci_dev *hdev, struct sk_buff *skb)
{
struct btmtksdio_dev *bdev = hci_get_drvdata(hdev);
struct hci_event_hdr *hdr = (void *)skb->data;
+ u8 evt = hdr->evt;
int err;

/* Fix up the vendor event id with 0xff for vendor specific instead
@@ -355,7 +356,7 @@ static int btmtksdio_recv_event(struct hci_dev *hdev, struct sk_buff *skb)
if (err < 0)
goto err_free_skb;

- if (hdr->evt == HCI_EV_VENDOR) {
+ if (evt == HCI_EV_VENDOR) {
if (test_and_clear_bit(BTMTKSDIO_TX_WAIT_VND_EVT,
&bdev->tx_state)) {
/* Barrier to sync with other CPUs */
--
2.35.1