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Date: Thu, 9 Jan 2014 22:28:10 +0000
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Eric Paris <eparis@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>, LKML <linux-kernel@vger.kernel.org>,
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Subject: Re: [PATCH] SELinux: Fix possible NULL pointer dereference in
 selinux_inode_permission()
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On Thu, Jan 09, 2014 at 11:05:45AM -0500, Eric Paris wrote:
> [adding lsm and selinux]
> 
> Am I just crazy, or was this bug discussed (and obviously not fixed)
> some time ago?
> 
> VFS can still use inodes after security_inode_free_security() was
> called...

Unrelated bug.

> > Assuming the VFS guys say that delaying __destroy_inode() is safe like
> > that, I like it better.  It also means that this is fixed for all LSMs,
> > not just SELinux...

Recall what your own code called from __destroy_inode() (fsnotify horrors)
is doing - you can't grab a mutex from RCU callback...

From mboxrd@z Thu Jan  1 00:00:00 1970
Date: Thu, 9 Jan 2014 22:28:10 +0000
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Eric Paris <eparis@redhat.com>
Subject: Re: [PATCH] SELinux: Fix possible NULL pointer dereference in
 selinux_inode_permission()
Message-ID: <20140109222809.GL10323@ZenIV.linux.org.uk>
References: <20140109101932.0508dec7@gandalf.local.home>
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On Thu, Jan 09, 2014 at 11:05:45AM -0500, Eric Paris wrote:
> [adding lsm and selinux]
> 
> Am I just crazy, or was this bug discussed (and obviously not fixed)
> some time ago?
> 
> VFS can still use inodes after security_inode_free_security() was
> called...

Unrelated bug.

> > Assuming the VFS guys say that delaying __destroy_inode() is safe like
> > that, I like it better.  It also means that this is fixed for all LSMs,
> > not just SELinux...

Recall what your own code called from __destroy_inode() (fsnotify horrors)
is doing - you can't grab a mutex from RCU callback...