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From: Eugene Teo <eugene@redhat.com>
To: Frank Filz <ffilzlnx@us.ibm.com>
Cc: NFS List <linux-nfs@vger.kernel.org>,
	NFS V4 Mailing List <nfsv4@linux-nfs.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	security@kernel.org, Trond Myklebust <trond.myklebust@fys.uio.no>,
	Bruce Fields <bfields@fieldses.org>
Subject: Re: [PATCH] nfs: Fix NFS v4 client handling of MAY_EXEC in 	nfs_permission.
Date: Tue, 19 May 2009 08:13:11 +0800	[thread overview]
Message-ID: <4A11F997.5030602@redhat.com> (raw)
In-Reply-To: <1242674983.4273.8.camel@dyn9047022153>

Frank Filz wrote:
> Sorry for the resend, got lkml address wrong...
> 
> The problem is that permission checking is skipped if atomic open is
> possible, but when exec opens a file, it just opens it O_READONLY which
> means EXEC permission will not be checked at that time.
> 
> This problem is observed by the following sequence (executed as root):
> 
> mount -t nfs4 server:/ /mnt4
> echo "ls" >/mnt4/foo
> chmod 744 /mnt4/foo
> su guest -c "mnt4/foo"
> 
> Signed-off-by: Frank Filz <ffilzlnx@us.ibm.com>

Tested-by: Eugene Teo <eugeneteo-X4ZF2iejbADYtjvyW6yDsg@public.gmane.org>

Thanks, Eugene

WARNING: multiple messages have this Message-ID (diff)
From: Eugene Teo <eugene@redhat.com>
To: Frank Filz <ffilzlnx@us.ibm.com>
Cc: NFS List <linux-nfs@vger.kernel.org>,
	NFS V4 Mailing List <nfsv4@linux-nfs.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	security@kernel.org, Trond Myklebust <trond.myklebust@fys.uio.no>,
	Bruce Fields <bfields@fieldses.org>
Subject: Re: [PATCH] nfs: Fix NFS v4 client handling of MAY_EXEC in 	nfs_permission.
Date: Tue, 19 May 2009 08:13:11 +0800	[thread overview]
Message-ID: <4A11F997.5030602@redhat.com> (raw)
In-Reply-To: <1242674983.4273.8.camel@dyn9047022153>

Frank Filz wrote:
> Sorry for the resend, got lkml address wrong...
> 
> The problem is that permission checking is skipped if atomic open is
> possible, but when exec opens a file, it just opens it O_READONLY which
> means EXEC permission will not be checked at that time.
> 
> This problem is observed by the following sequence (executed as root):
> 
> mount -t nfs4 server:/ /mnt4
> echo "ls" >/mnt4/foo
> chmod 744 /mnt4/foo
> su guest -c "mnt4/foo"
> 
> Signed-off-by: Frank Filz <ffilzlnx@us.ibm.com>

Tested-by: Eugene Teo <eugeneteo@kernel.sg>

Thanks, Eugene

  reply	other threads:[~2009-05-19  0:14 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-18 19:29 [PATCH] nfs: Fix NFS v4 client handling of MAY_EXEC in nfs_permission Frank Filz
2009-05-18 19:29 ` Frank Filz
2009-05-19  0:13 ` Eugene Teo [this message]
2009-05-19  0:13   ` Eugene Teo
  -- strict thread matches above, loose matches on Subject: below --
2009-05-18 19:25 Frank Filz
2009-05-09  2:55 [NFS] " Frank Filz
2009-05-13  8:50 ` Eugene Teo

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