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

Peilin Ye yepeilin.cs at gmail.com
Thu Jul 9 13:02:24 UTC 2020

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:


Reported-by: syzbot+d8489a79b781849b9c46 at syzkaller.appspotmail.com
Signed-off-by: Peilin Ye <yepeilin.cs at gmail.com>
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))
 	if (hci_dev_test_flag(hdev, HCI_PERIODIC_INQ))

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