diff mbox series

[Linux-kernel-mentees,v3] net/bluetooth: Fix slab-out-of-bounds read in hci_extended_inquiry_result_evt()

Message ID 20200710160915.228980-1-yepeilin.cs@gmail.com
State Awaiting Upstream
Delegated to: David Miller
Headers show
Series [Linux-kernel-mentees,v3] net/bluetooth: Fix slab-out-of-bounds read in hci_extended_inquiry_result_evt() | expand

Commit Message

Peilin Ye July 10, 2020, 4:09 p.m. UTC 
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: syzbot+d8489a79b781849b9c46@syzkaller.appspotmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
---
Change in v3:
    - Minimum `skb->len` requirement was 1 byte inaccurate since `info`
      starts from `skb->data + 1`. Fix it.

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(-)

Comments

Marcel Holtmann July 10, 2020, 5:08 p.m. UTC | #1 
Hi Peilin,

> 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: syzbot+d8489a79b781849b9c46@syzkaller.appspotmail.com
> Cc: stable@vger.kernel.org
> Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
> ---
> Change in v3:
>    - Minimum `skb->len` requirement was 1 byte inaccurate since `info`
>      starts from `skb->data + 1`. Fix it.
> 
> 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(-)

patch has been applied to bluetooth-next tree.

Regards

Marcel
diff mbox series

Patch

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 03a0759f2fc2..13d8802b8137 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) + 1)
 		return;
 
 	if (hci_dev_test_flag(hdev, HCI_PERIODIC_INQ))