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Subject: Re: [Linux-kernel-mentees] [PATCH v3] net/bluetooth: Fix
 slab-out-of-bounds read in hci_extended_inquiry_result_evt()
From:   Marcel Holtmann <marcel@holtmann.org>
In-Reply-To: <20200710160915.228980-1-yepeilin.cs@gmail.com>
Date:   Fri, 10 Jul 2020 19:08:51 +0200
Cc:     Johan Hedberg <johan.hedberg@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Russell King <linux@armlinux.org.uk>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Bluetooth Kernel Mailing List 
        <linux-bluetooth@vger.kernel.org>,
        "open list:NETWORKING [GENERAL]" <netdev@vger.kernel.org>,
        syzkaller-bugs@googlegroups.com,
        linux-kernel-mentees@lists.linuxfoundation.org,
        linux-kernel@vger.kernel.org
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Message-Id: <43E6945B-1FFE-4283-9F1B-E84AFDCB528F@holtmann.org>
References: <20200709130224.214204-1-yepeilin.cs@gmail.com>
 <20200710160915.228980-1-yepeilin.cs@gmail.com>
To:     Peilin Ye <yepeilin.cs@gmail.com>
Sender: linux-kernel-owner@vger.kernel.org
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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