From: "David S. Miller" <davem@redhat.com>
To: Glenn Fowler <gsf@research.att.com>
Cc: dgk@research.att.com, linux-kernel@vger.kernel.org, netdev@oss.sgi.com
Subject: Re: kernel bug in socketpair()
Date: Wed, 23 Jul 2003 10:00:43 -0700 [thread overview]
Message-ID: <20030723100043.18d5b025.davem@redhat.com> (raw)
In-Reply-To: <200307231656.MAA69129@raptor.research.att.com>
On Wed, 23 Jul 2003 12:56:12 -0400 (EDT)
Glenn Fowler <gsf@research.att.com> wrote:
> the problem is that linux took an implementation shortcut by symlinking
> /dev/fd/N -> /proc/self/fd/N
> and by the time the kernel sees /proc/self/fd/N the "self"-ness is apparently
> lost, and it is forced to do the security checks
None of this is true. If you open /proc/self/fd/N directly the problem
is still there.
> if the /proc fd open code has access to the original /proc/PID/fd/N path
> then it can do dup(atoi(N)) when the PID is the current process without
> affecting security
If we're talking about the current process, there is no use in using
/proc/*/fd/N to open a file descriptor in the first place, you can
simply call open(N,...)
I've personally always viewed /proc/*/fd/N as a way to see who has
various files or sockets open, ie. a debugging tool, not as a generic
way for processes to get access to each other's FDs.
There is an existing mechanism, a portable non-Linux one, that you
can use to do that.
Pass the fd over a UNIX domain socket if you want that, truly.
That works on every system.
next prev parent reply other threads:[~2003-07-23 16:47 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-07-23 14:28 Re: kernel bug in socketpair() David Korn
2003-07-23 14:46 ` David S. Miller
2003-07-23 16:56 ` Glenn Fowler
2003-07-23 17:00 ` David S. Miller [this message]
2003-07-23 17:24 ` Glenn Fowler
2003-07-23 17:31 ` David S. Miller
2003-07-23 18:14 ` Glenn Fowler
2003-07-23 18:23 ` David S. Miller
2003-07-23 18:54 ` Glenn Fowler
2003-07-23 19:04 ` David S. Miller
2003-07-23 19:11 ` Glenn Fowler
2003-07-23 19:14 ` David S. Miller
2003-07-23 19:29 ` Glenn Fowler
2003-07-23 19:56 ` David S. Miller
2003-07-23 22:24 ` jw schultz
2003-07-23 19:08 ` Alan Cox
2003-07-23 19:41 ` Andreas Jellinghaus
2003-07-23 17:50 ` Alan Cox
2003-07-23 23:27 ` Bill Rugolsky Jr.
-- strict thread matches above, loose matches on Subject: below --
2003-07-23 13:32 David Korn
2003-07-23 14:04 ` David S. Miller
2003-07-23 14:20 ` Alan Cox
2003-07-23 15:36 ` David S. Miller
2003-07-23 16:13 ` Alan Cox
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