From: Kees Cook <keescook@chromium.org>
To: Erick Archer <erick.archer@outlook.com>
Cc: Jiri Slaby <jirislaby@kernel.org>,
Luiz Augusto von Dentz <luiz.dentz@gmail.com>,
Marcel Holtmann <marcel@holtmann.org>,
Johan Hedberg <johan.hedberg@gmail.com>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
"Gustavo A. R. Silva" <gustavoars@kernel.org>,
Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Bill Wendling <morbo@google.com>,
Justin Stitt <justinstitt@google.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Geert Uytterhoeven <geert@linux-m68k.org>,
linux-bluetooth@vger.kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org,
llvm@lists.linux.dev
Subject: Re: [PATCH v2] tty: rfcomm: prefer struct_size over open coded arithmetic
Date: Mon, 13 May 2024 11:51:37 -0700 [thread overview]
Message-ID: <202405131150.31B872F41A@keescook> (raw)
In-Reply-To: <AS8PR02MB72379B760CF7B6A26A69C5558BE22@AS8PR02MB7237.eurprd02.prod.outlook.com>
On Mon, May 13, 2024 at 07:12:57PM +0200, Erick Archer wrote:
> Hi Kees, Jiri and Luiz,
> First of all, thanks for the reviews.
>
> On Mon, May 13, 2024 at 12:29:04PM -0400, Luiz Augusto von Dentz wrote:
> > Hi Jiri, Eric,
> >
> > On Mon, May 13, 2024 at 1:07 AM Jiri Slaby <jirislaby@kernel.org> wrote:
> > >
> > > On 12. 05. 24, 13:17, Erick Archer wrote:
> > > > This is an effort to get rid of all multiplications from allocation
> > > > functions in order to prevent integer overflows [1][2].
> > > >
> > > > As the "dl" variable is a pointer to "struct rfcomm_dev_list_req" and
> > > > this structure ends in a flexible array:
> > > ...
> > > > --- a/include/net/bluetooth/rfcomm.h
> > > > +++ b/include/net/bluetooth/rfcomm.h
> > > ...
> > > > @@ -528,12 +527,12 @@ static int rfcomm_get_dev_list(void __user *arg)
> > > > list_for_each_entry(dev, &rfcomm_dev_list, list) {
> > > > if (!tty_port_get(&dev->port))
> > > > continue;
> > > > - (di + n)->id = dev->id;
> > > > - (di + n)->flags = dev->flags;
> > > > - (di + n)->state = dev->dlc->state;
> > > > - (di + n)->channel = dev->channel;
> > > > - bacpy(&(di + n)->src, &dev->src);
> > > > - bacpy(&(di + n)->dst, &dev->dst);
> > > > + di[n].id = dev->id;
> > > > + di[n].flags = dev->flags;
> > > > + di[n].state = dev->dlc->state;
> > > > + di[n].channel = dev->channel;
> > > > + bacpy(&di[n].src, &dev->src);
> > > > + bacpy(&di[n].dst, &dev->dst);
> > >
> > > This does not relate much to "prefer struct_size over open coded
> > > arithmetic". It should have been in a separate patch.
> >
> > +1, please split these changes into its own patch so we can apply it separately.
>
> Ok, no problem. Also, I will simplify the "bacpy" lines with direct
> assignments as Kees suggested:
>
> di[n].src = dev->src;
> di[n].dst = dev->dst;
>
> instead of:
>
> bacpy(&di[n].src, &dev->src);
> bacpy(&di[n].dst, &dev->dst);
I think that's a separate thing and you can leave bacpy() as-is for now.
--
Kees Cook
prev parent reply other threads:[~2024-05-13 18:51 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-12 11:17 [PATCH v2] tty: rfcomm: prefer struct_size over open coded arithmetic Erick Archer
2024-05-13 3:03 ` Kees Cook
2024-05-13 5:07 ` Jiri Slaby
2024-05-13 16:29 ` Luiz Augusto von Dentz
2024-05-13 17:12 ` Erick Archer
2024-05-13 18:51 ` Kees Cook [this message]
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