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From:   zhang haiming <tcs.kernel@gmail.com>
Date:   Tue, 30 Aug 2022 15:04:36 +0800
Message-ID: <CAB2z9exjHXMTA5dHFwdf0V+niQZ4ER00pT5Kwz2ybiRHqDC2ow@mail.gmail.com>
Subject: Re: [PATCH] net/ieee802154: fix uninit value bug in dgram_sendmsg
To:     Stefan Schmidt <stefan@datenfreihafen.org>
Cc:     Alexander Aring <aahringo@redhat.com>,
        Alexander Aring <alex.aring@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        linux-wpan - ML <linux-wpan@vger.kernel.org>,
        Network Development <netdev@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Haimin Zhang <tcs_kernel@tencent.com>
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Thanks to all.
I have sent patch v2 to fix this.

On Mon, Aug 29, 2022 at 5:08 PM Stefan Schmidt
<stefan@datenfreihafen.org> wrote:
>
>
> Hello Alex.
>
> On 23.08.22 14:22, Alexander Aring wrote:
> > Hi,
> >
> > On Tue, Aug 23, 2022 at 5:42 AM Stefan Schmidt
> > <stefan@datenfreihafen.org> wrote:
> >>
> >> Hello.
> >>
> >> On 22.08.22 09:19, Haimin Zhang wrote:
> >>> There is uninit value bug in dgram_sendmsg function in
> >>> net/ieee802154/socket.c when the length of valid data pointed by the
> >>> msg->msg_name isn't verified.
> >>>
> >>> This length is specified by msg->msg_namelen. Function
> >>> ieee802154_addr_from_sa is called by dgram_sendmsg, which use
> >>> msg->msg_name as struct sockaddr_ieee802154* and read it, that will
> >>> eventually lead to uninit value read. So we should check the length of
> >>> msg->msg_name is not less than sizeof(struct sockaddr_ieee802154)
> >>> before entering the ieee802154_addr_from_sa.
> >>>
> >>> Signed-off-by: Haimin Zhang <tcs_kernel@tencent.com>
> >>
> >>
> >> This patch has been applied to the wpan tree and will be
> >> part of the next pull request to net. Thanks!
> >
> > For me this patch is buggy or at least it is questionable how to deal
> > with the size of ieee802154_addr_sa here.
>
> You are right. I completely missed this. Thanks for spotting!
>
> > There should be a helper to calculate the size which depends on the
> > addr_type field. It is not required to send the last 6 bytes if
> > addr_type is IEEE802154_ADDR_SHORT.
> > Nitpick is that we should check in the beginning of that function.
>
> Haimin, in ieee802154 we could have two different sizes for
> ieee802154_addr_sa depending on the addr_type. We have short and
> extended addresses.
>
> Could you please rework this patch to take this into account as Alex
> suggested?
>
> I reverted your original patch from my tree.
>
> regards
> Stefan Schmidt