From: Eric Paris <eparis@redhat.com>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Steven Rostedt <rostedt@goodmis.org>,
LKML <linux-kernel@vger.kernel.org>,
Stephen Smalley <sds@tycho.nsa.gov>,
James Morris <james.l.morris@oracle.com>,
Paul Moore <paul@paul-moore.com>,
Andrew Morton <akpm@linux-foundation.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
stable <stable@vger.kernel.org>
Subject: Re: [PATCH] SELinux: Fix possible NULL pointer dereference in selinux_inode_permission()
Date: Thu, 09 Jan 2014 17:18:09 -0500 [thread overview]
Message-ID: <1389305889.15209.75.camel@localhost> (raw)
In-Reply-To: <20140109221303.GI10323@ZenIV.linux.org.uk>
On Thu, 2014-01-09 at 22:13 +0000, Al Viro wrote:
> On Thu, Jan 09, 2014 at 10:31:55AM -0500, Eric Paris wrote:
> > Didn't Al find this/something very similar. I really hate this
> > solution. Why should every LSM try to understand the intimate
> > lifetime rules of the parent subsystems? The real problem is that
> > inode_free_security() is being called while the inode is still in use.
> > While I agree with the assessment, I disagree with the solution. Let
> > me try to find where Al and Christoph talked about this....
>
> Because LSM has stuck its fingers into the guts of those filesystems,
> obviously.
>
> Just RCU-delay freeing the damn thing and treat NULL ->i_security in
> ->permission() (which can happen only with MAY_NOT_BLOCK in mask) as
> "return -ECHILD and let the caller deal with that".
>
> Modifying every ->destroy_inode() is obviously wrong - there's a lot more
> filesystems than LSM buggers in the tree.
We just want the same lifetime as the inode. Allocate the security blob
when the inode is allocated and free the security blob when the inode is
freed.
If we -rcu delay the free'ing we shouldn't need the NULL check, right?
-Eric
next prev parent reply other threads:[~2014-01-09 22:19 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-09 15:19 [PATCH] SELinux: Fix possible NULL pointer dereference in selinux_inode_permission() Steven Rostedt
2014-01-09 15:31 ` Eric Paris
2014-01-09 15:51 ` Steven Rostedt
2014-01-09 15:57 ` Eric Paris
2014-01-09 16:05 ` Eric Paris
2014-01-09 16:05 ` Eric Paris
2014-01-09 16:10 ` Stephen Smalley
2014-01-09 16:10 ` Stephen Smalley
2014-01-09 16:22 ` Steven Rostedt
2014-01-09 16:22 ` Steven Rostedt
2014-01-09 16:25 ` Eric Paris
2014-01-09 16:25 ` Eric Paris
2014-01-09 20:20 ` Mimi Zohar
2014-01-09 20:20 ` Mimi Zohar
2014-01-09 20:24 ` Eric Paris
2014-01-09 20:24 ` Eric Paris
2014-01-09 22:28 ` Al Viro
2014-01-09 22:28 ` Al Viro
2014-01-09 22:17 ` Al Viro
2014-01-09 22:13 ` Al Viro
2014-01-09 22:18 ` Eric Paris [this message]
2014-01-09 22:25 ` Al Viro
2014-01-09 22:45 ` Eric Paris
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