From: Ian Campbell <ijc@hellion.org.uk>
To: Salvatore Mesoraca <s.mesoraca16@gmail.com>,
Solar Designer <solar@openwall.com>
Cc: David Laight <David.Laight@aculab.com>,
Alan Cox <gnomes@lxorguk.ukuu.org.uk>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Kernel Hardening <kernel-hardening@lists.openwall.com>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Jann Horn <jannh@google.com>, Kees Cook <keescook@chromium.org>,
"Eric W. Biederman" <ebiederm@xmission.com>
Subject: Re: [kernel-hardening] Re: [PATCH v3 2/2] Protected O_CREAT open in sticky directories
Date: Thu, 30 Nov 2017 14:57:06 +0000 [thread overview]
Message-ID: <1512053826.26048.8.camel@hellion.org.uk> (raw)
In-Reply-To: <CAJHCu1+yjSCReBGG4=K2Kx-iTjVxbSTqacM9bNVPNdg74pGoow@mail.gmail.com>
On Thu, 2017-11-30 at 15:39 +0100, Salvatore Mesoraca wrote:
> 2017-11-27 1:26 GMT+01:00 Solar Designer <solar@openwall.com>:
> > On Fri, Nov 24, 2017 at 12:43:47PM +0100, Salvatore Mesoraca wrote:
> > > 2017-11-24 11:53 GMT+01:00 David Laight <David.Laight@aculab.com>
> > > :
> > > > From: Alan Cox
> > > > > Sent: 22 November 2017 16:52
> > > > >
> > > > > On Wed, 22 Nov 2017 09:01:46 +0100 Salvatore Mesoraca <s.meso
> > > > > raca16@gmail.com> wrote:
> > > > >
> > > > > > Disallows O_CREAT open missing the O_EXCL flag, in world or
> > > > > > group writable directories, even if the file doesn't exist
> > > > > > yet.
> > > > > > With few exceptions (e.g. shared lock files based on
> > > > > > flock())
> >
> > Why would "shared lock files based on flock()" need O_CREAT without
> > O_EXCL? Where specifically are they currently used that way?
>
> I don't think that they *need* to act like this, but this is how
> util-linux's flock(1) currently works.
> And it doesn't seem an unreasonable behavior from their perspective,
I thought that too, specifically I reasoned that using O_EXCL would
defeat the purpose of the _shared_ flock(), wouldn't it?
Ian.
next prev parent reply other threads:[~2017-11-30 15:18 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-22 8:01 [PATCH v3 0/2] Restrict dangerous open in sticky directories Salvatore Mesoraca
2017-11-22 8:01 ` [PATCH v3 1/2] Protected FIFOs and regular files Salvatore Mesoraca
2017-11-23 22:43 ` [kernel-hardening] " Tobin C. Harding
2017-11-24 8:24 ` Salvatore Mesoraca
2017-11-22 8:01 ` [PATCH v3 2/2] Protected O_CREAT open in sticky directories Salvatore Mesoraca
2017-11-22 13:22 ` Matthew Wilcox
2017-11-24 8:29 ` Salvatore Mesoraca
2017-11-22 16:51 ` Alan Cox
2017-11-24 8:31 ` Salvatore Mesoraca
2017-11-24 10:53 ` David Laight
2017-11-24 11:43 ` Salvatore Mesoraca
2017-11-24 11:53 ` David Laight
2017-11-26 11:29 ` Salvatore Mesoraca
2017-11-27 0:26 ` Solar Designer
2017-11-30 14:39 ` Salvatore Mesoraca
2017-11-30 14:57 ` Ian Campbell [this message]
2017-11-30 16:30 ` [kernel-hardening] " Solar Designer
2017-12-05 10:21 ` Salvatore Mesoraca
2017-12-07 21:47 ` Solar Designer
2017-12-11 12:08 ` Salvatore Mesoraca
2017-11-23 22:57 ` Tobin C. Harding
2017-11-24 8:34 ` Salvatore Mesoraca
2017-11-30 16:53 ` David Laight
2017-11-30 17:51 ` Solar Designer
2017-12-01 9:46 ` David Laight
2017-12-01 15:52 ` Alan Cox
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