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+d8489a79b781849b9...@syzkaller.appspotmail.com
Cc: sta...@vger.kernel.org
Signed-off-by: Peilin Ye <yepeilin...@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(-)

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))
-- 
2.25.1

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