From 56897b217a1d0a91c9920cb418d6b3fe922f590a Mon Sep 17 00:00:00 2001
From: Kefeng Wang <wangkefeng.wang@huawei.com>
Date: Sat, 23 Feb 2019 12:33:27 +0800
Subject: [PATCH] Bluetooth: hci_ldisc: Postpone HCI_UART_PROTO_READY bit set in hci_uart_set_proto()
Git-commit: 56897b217a1d0a91c9920cb418d6b3fe922f590a
Patch-mainline: v5.1-rc1
References: bsc#1051510, CVE-2019-15917, bsc#1149539
task A: task B:
hci_uart_set_proto flush_to_ldisc
- p->open(hu) -> h5_open //alloc h5 - receive_buf
- set_bit HCI_UART_PROTO_READY - tty_port_default_receive_buf
- hci_uart_register_dev - tty_ldisc_receive_buf
- hci_uart_tty_receive
- test_bit HCI_UART_PROTO_READY
- h5_recv
- clear_bit HCI_UART_PROTO_READY while() {
- p->open(hu) -> h5_close //free h5
- h5_rx_3wire_hdr
- h5_reset() //use-after-free
}
It could use ioctl to set hci uart proto, but there is
a use-after-free issue when hci_uart_register_dev() fail in
hci_uart_set_proto(), see stack above, fix this by setting
HCI_UART_PROTO_READY bit only when hci_uart_register_dev()
return success.
Reported-by: syzbot+899a33dc0fa0dbaf06a6@syzkaller.appspotmail.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Jeremy Cline <jcline@redhat.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/bluetooth/hci_ldisc.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c
index 4918fefc4a6f..9562e72c1ae5 100644
--- a/drivers/bluetooth/hci_ldisc.c
+++ b/drivers/bluetooth/hci_ldisc.c
@@ -696,14 +696,13 @@ static int hci_uart_set_proto(struct hci_uart *hu, int id)
return -EPROTONOSUPPORT;
hu->proto = p;
- set_bit(HCI_UART_PROTO_READY, &hu->flags);
err = hci_uart_register_dev(hu);
if (err) {
- clear_bit(HCI_UART_PROTO_READY, &hu->flags);
return err;
}
+ set_bit(HCI_UART_PROTO_READY, &hu->flags);
return 0;
}
--
2.16.4