From: Eric Paris <eparis@redhat.com>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: linux-kernel@vger.kernel.org, alan <alan@redhat.com>,
aviro@redhat.com, drepper@redhat.com, hch@infradead.org,
sds@tycho.nsa.gov, jmorris@namei.org
Subject: Re: [RFC] correct flags to f_mode conversion in __dentry_open
Date: Wed, 12 Mar 2008 14:41:00 -0400 [thread overview]
Message-ID: <1205347260.2925.0.camel@localhost.localdomain> (raw)
In-Reply-To: <20080312183441.GJ27894@ZenIV.linux.org.uk>
On Wed, 2008-03-12 at 18:34 +0000, Al Viro wrote:
> On Wed, Mar 12, 2008 at 02:25:27PM -0400, Eric Paris wrote:
> > I recently tried to add an SELinux BUG_ON in the case where the kernel
> > made a permission request for no permissions and was able to stumble
> > over it with something as simple as
> >
> > open("/dev/null", 3);
> >
> > Notice that 3 == (O_RDWR | O_WRONLY)
> >
> > First question, is 3 ever a valid flag from from userspace to sys_open?
>
> Yes. "Check for both read and write permissions, set neither FMODE_READ
> nor FMODE_WRITE".
>
> Don't break drivers, please - some use that for "ioctl-only" opens,
> with special semantics for those.
Ok, I'll just make SELinux happy allow the request if we don't have
FMODE_READ or FMODE_WRITE set.
-Eric
next prev parent reply other threads:[~2008-03-12 18:43 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-12 18:25 Eric Paris
2008-03-12 18:34 ` Al Viro
2008-03-12 18:41 ` Eric Paris [this message]
2008-03-12 18:47 ` Andreas Schwab
2008-03-15 21:59 ` Alan Cox
2008-03-15 22:00 ` Alexander Viro
2008-03-17 10:45 ` Christoph Hellwig
2008-05-21 17:54 ` Michael Kerrisk
2008-05-22 2:10 ` James Morris
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