2020-07-09 13:05:45

by Peilin Ye

Subject: [Linux-kernel-mentees] [PATCH v2] net/bluetooth: Fix slab-out-of-bounds read in hci_extended_inquiry_result_evt()

Check upon `num_rsp` is insufficient. A malformed event packet with a
large `num_rsp` number makes hci_extended_inquiry_result_evt() go out
of bounds. Fix it.

This patch fixes the following syzbot bug:

https://syzkaller.appspot.com/bug?id=4bf11aa05c4ca51ce0df86e500fce486552dc8d2

Reported-by: [email protected]
Signed-off-by: Peilin Ye <[email protected]>
---
Changes in v2:
- Use `skb->len` instead of `skb->truesize` as the length limit.
- Leave `num_rsp` as of type `int`.

net/bluetooth/hci_event.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 03a0759f2fc2..91cb3707d20a 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -4375,7 +4375,7 @@ static void hci_extended_inquiry_result_evt(struct hci_dev *hdev,

BT_DBG("%s num_rsp %d", hdev->name, num_rsp);

- if (!num_rsp)
+ if (!num_rsp || skb->len < num_rsp * sizeof(*info))
return;

if (hci_dev_test_flag(hdev, HCI_PERIODIC_INQ))
--
2.25.1

2020-07-10 10:44:13

by Greg Kroah-Hartman

Subject: Re: [Linux-kernel-mentees] [PATCH v2] net/bluetooth: Fix slab-out-of-bounds read in hci_extended_inquiry_result_evt()

On Thu, Jul 09, 2020 at 09:02:24AM -0400, Peilin Ye wrote:
> Check upon `num_rsp` is insufficient. A malformed event packet with a
> large `num_rsp` number makes hci_extended_inquiry_result_evt() go out
> of bounds. Fix it.
>
> This patch fixes the following syzbot bug:
>
> https://syzkaller.appspot.com/bug?id=4bf11aa05c4ca51ce0df86e500fce486552dc8d2
>
> Reported-by: [email protected]
> Signed-off-by: Peilin Ye <[email protected]>

Acked-by: Greg Kroah-Hartman <[email protected]>

Bluetooth maintainers, can you also add a cc: stable on this so it gets
picked up properly there?

thanks,

greg k-h

2021-07-01 16:42:23

by Alexander Larkin

Subject: Re: maybe similar bug exists for HCI_EV_INQUIRY_RESULT* like [Linux-kernel-mentees] [PATCH v2] net/bluetooth: slab-out-of-bounds read in hci_extended_inquiry_result_evt()

For the net/bluetooth/hci_event.c , maybe similar bug could be inside
hci_inquiry_result_with_rssi_evt() that is HCI_EV_INQUIRY_RESULT_WITH_RSSI
and inside hci_inquiry_result_evt() that is HCI_EV_INQUIRY_RESULT.