[PATCH 4.9 054/212] Bluetooth: Fix slab-out-of-bounds read in hci_extended_inquiry_result_evt()

[Greg Kroah-Hartman]

From: Peilin Ye <yepeilin.cs@xxxxxxxxx>

commit 51c19bf3d5cfaa66571e4b88ba2a6f6295311101 upstream.

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@xxxxxxxxxxxxxxxxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Peilin Ye <yepeilin.cs@xxxxxxxxx>
Acked-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Marcel Holtmann <marcel@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

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

--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -3826,7 +3826,7 @@ static void hci_extended_inquiry_result_
 
 	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))