From: Eric Biggers <ebiggers3@gmail.com>
To: David Miller <davem@davemloft.net>
Cc: g.nault@alphalink.fr, linux-ppp@vger.kernel.org,
paulus@samba.org, netdev@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
syzkaller-bugs@googlegroups.com, ebiggers@google.com
Subject: Re: [PATCH] ppp: remove the PPPIOCDETACH ioctl
Date: Wed, 23 May 2018 21:17:09 +0000 [thread overview]
Message-ID: <20180523211709.GA63112@gmail.com> (raw)
In-Reply-To: <20180523.115636.2241611659399097483.davem@davemloft.net>
On Wed, May 23, 2018 at 11:56:36AM -0400, David Miller wrote:
> From: Guillaume Nault <g.nault@alphalink.fr>
> Date: Wed, 23 May 2018 15:57:08 +0200
>
> > I'd rather add
> > + if (cmd = PPPIOCDETACH) {
> > + err = -EINVAL;
> > + goto out;
> > + }
> >
> > Making PPPIOCDETACH unknown to ppp_generic means that the ioctl would
> > be handled by the underlying channel when pf->kind = CHANNEL (see the
> > chan->ops->ioctl() call further down). That shouldn't be a problem per
> > se, but even though PPPIOCDETACH is unsupported, I feel that it should
> > remain a ppp_generic thing. I don't really want its value to be reused
> > for other purposes in the future or have different behaviour depending
> > on the underlying channel.
> >
> > Also PPPIOCDETACH can already fail with -EINVAL. Therefore, if ever
> > there really were programs out there using this call, they'd already
> > have to handle this case. Unconditionally returning -EINVAL would
> > further minimise possibilities for breakage.
>
> I agree.
Okay, I'll do that and leave the ioctl number reserved.
I will add a pr_warn_once() too.
Thanks,
- Eric
next prev parent reply other threads:[~2018-05-23 21:17 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <f403043d0f18f879cc056648a875@google.com>
2018-05-14 6:11 ` KASAN: use-after-free Read in remove_wait_queue (2) Eric Biggers
2018-05-18 16:02 ` Guillaume Nault
2018-05-23 3:29 ` Eric Biggers
2018-05-23 3:59 ` [PATCH] ppp: remove the PPPIOCDETACH ioctl Eric Biggers
2018-05-23 13:57 ` Guillaume Nault
2018-05-23 15:56 ` David Miller
2018-05-23 21:17 ` Eric Biggers [this message]
2018-05-23 21:37 ` [PATCH v2] " Eric Biggers
2018-05-23 23:04 ` Paul Mackerras
2018-05-24 14:04 ` Guillaume Nault
2018-05-25 2:55 ` David Miller
2018-06-06 9:01 ` Walter Harms
2018-05-23 13:26 ` KASAN: use-after-free Read in remove_wait_queue (2) Guillaume Nault
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