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From: Eric Dumazet <edumazet@google.com>
Date: Fri, 5 Apr 2024 19:45:37 +0200
Message-ID: <CANn89i+TB_cb9tSHW+8dAiqWXpAmtw=ktVG3WujiJfL2WcASiA@mail.gmail.com>
Subject: Re: [PATCH net] Bluetooth: validate setsockopt( BT_PKT_STATUS /
 BT_DEFER_SETUP) user input
To: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Cc: "David S . Miller" <davem@davemloft.net>, Jakub Kicinski <kuba@kernel.org>, 
	Paolo Abeni <pabeni@redhat.com>, netdev@vger.kernel.org, eric.dumazet@gmail.com, 
	syzbot <syzkaller@googlegroups.com>, Marcel Holtmann <marcel@holtmann.org>, 
	Johan Hedberg <johan.hedberg@gmail.com>, linux-bluetooth@vger.kernel.org
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On Fri, Apr 5, 2024 at 7:38=E2=80=AFPM Luiz Augusto von Dentz
<luiz.dentz@gmail.com> wrote:
>
> Hi Eric,
>
> On Fri, Apr 5, 2024 at 12:30=E2=80=AFPM Eric Dumazet <edumazet@google.com=
> wrote:
> >
> > On Fri, Apr 5, 2024 at 6:24=E2=80=AFPM Luiz Augusto von Dentz
> > <luiz.dentz@gmail.com> wrote:
> > >
> > ave used this so far (without risking a kernel bug)
> > >
> > > Fair enough, if we don't really have any risk of breaking the API
> > > (would result in using uninitialized memory) then I propose we do
> > > something like this:
> > >
> > > https://gist.github.com/Vudentz/c9092e8a3cb1e7e6a8fd384a51300eee
> > >
> > > That said perhaps copy_from_sockptr shall really take into account
> > > both source and destination lengths so it could incorporate the check
> > > e.g. if (dst_size > src_size) but that might result in changing every
> > > user of copy_from_sockptr thus I left it to be specific to bluetooth.
> >
> > Make sure to return -EINVAL if the user provided length is too small,
> > not -EFAULT.
>
> Sure, there was also a use of -EOVERFLOW and the fact we are using the
> return of copy_from_sockptr so if it fails we just return -EFAULT
> anyway, so if we do start returning the error from the like
> bt_copy_from_sockptr then we better figure out the errors it returns
> are proper.
>
> Btw, do you want me to spin a new version containing these changes or
> you would like to incorporate them into your patch and spin a v2?

Please go ahead and submit your own patch(es), thanks !