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From: David Miller <davem@davemloft.net>
To: g.nault@alphalink.fr
Cc: ebiggers3@gmail.com, 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 11:56:36 -0400 (EDT)	[thread overview]
Message-ID: <20180523.115636.2241611659399097483.davem@davemloft.net> (raw)
In-Reply-To: <20180523135708.GB1569@alphalink.fr>

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.

WARNING: multiple messages have this Message-ID (diff)
From: David Miller <davem@davemloft.net>
To: g.nault@alphalink.fr
Cc: ebiggers3@gmail.com, 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 15:56:36 +0000	[thread overview]
Message-ID: <20180523.115636.2241611659399097483.davem@davemloft.net> (raw)
In-Reply-To: <20180523135708.GB1569@alphalink.fr>

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.

  reply	other threads:[~2018-05-23 15:56 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-28 16:59 KASAN: use-after-free Read in remove_wait_queue (2) syzbot
2018-05-14  6:11 ` Eric Biggers
2018-05-14  6:11   ` Eric Biggers
2018-05-18 16:02   ` Guillaume Nault
2018-05-18 16:02     ` Guillaume Nault
2018-05-23  3:29     ` Eric Biggers
2018-05-23  3:29       ` Eric Biggers
2018-05-23  3:59       ` [PATCH] ppp: remove the PPPIOCDETACH ioctl Eric Biggers
2018-05-23  3:59         ` Eric Biggers
2018-05-23 13:57         ` Guillaume Nault
2018-05-23 13:57           ` Guillaume Nault
2018-05-23 15:56           ` David Miller [this message]
2018-05-23 15:56             ` David Miller
2018-05-23 21:17             ` Eric Biggers
2018-05-23 21:17               ` Eric Biggers
2018-05-23 21:37         ` [PATCH v2] " Eric Biggers
2018-05-23 21:37           ` Eric Biggers
2018-05-23 23:04           ` Paul Mackerras
2018-05-23 23:04             ` Paul Mackerras
2018-05-24 14:04           ` Guillaume Nault
2018-05-24 14:04             ` Guillaume Nault
2018-05-25  2:55           ` David Miller
2018-05-25  2:55             ` David Miller
2018-06-06  9:01           ` Walter Harms
2018-06-06  9:01             ` Walter Harms
2018-05-23 13:26       ` KASAN: use-after-free Read in remove_wait_queue (2) Guillaume Nault
2018-05-23 13:26         ` Guillaume Nault

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