Re: kernel bug in socketpair()

From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Glenn Fowler <gsf@research.att.com>
Cc: davem@redhat.com, dgk@research.att.com,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	netdev@oss.sgi.com
Subject: Re: kernel bug in socketpair()
Date: 23 Jul 2003 18:50:41 +0100	[thread overview]
Message-ID: <1058982641.5520.98.camel@dhcp22.swansea.linux.org.uk> (raw)
In-Reply-To: <200307231656.MAA69129@raptor.research.att.com>

On Mer, 2003-07-23 at 17:56, Glenn Fowler wrote:
> you can eliminate the security implications for all fd types by
> simply translating
> 	open("/dev/fd/N",...)
> to
> 	dup(atoi(N))
> w.r.t. fd N in the current process

This has very different semantics. Consider lseek().

> otherwise there is a bug in the /dev/fd/N -> /proc/self/fd/N implementation
> and /dev/fd/N should be separated out to its (original) dup(atoi(N))
> semantics

I don't see a bug. I see differing behaviour between Linux and BSD on a
completely non standards defined item. Also btw nobody ever really wrote
a /dev/fd/ for Linux - it was just a byproduct of the proc stuff someone
noticed. I guess someone could write a Plan-9 style dev/fd or devfdfs
for Linux if they wanted.

Alan