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From: Christoph Hellwig <hch@infradead.org>
To: Andreas Gruenbacher <agruen@suse.de>
Cc: Christoph Hellwig <hch@infradead.org>, Tony Jones <tonyj@suse.de>,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	chrisw@sous-sol.org, linux-security-module@vger.kernel.org,
	viro@zeniv.linux.org.uk
Subject: Re: [RFC 0/28] Patches to pass vfsmount to LSM inode security hooks
Date: Tue, 6 Feb 2007 09:52:31 +0000	[thread overview]
Message-ID: <20070206095231.GD5328@infradead.org> (raw)
In-Reply-To: <200702051813.26958.agruen@suse.de>

On Mon, Feb 05, 2007 at 06:13:26PM -0800, Andreas Gruenbacher wrote:
> On Monday 05 February 2007 10:44, Christoph Hellwig wrote:
> > Looking at the actual patches I see you're lazy in a lot of places.
> > Please make sure that when you introduce a vfsmount argument somewhere
> > that it is _always_ passed and not just when it's conveniant.  Yes, that's
> > more work, but then again if you're not consistant anyone half-serious
> > will laught at a security model using this infrasturcture.
> 
> It may appear like laziness, but it's not. Let's look at where we're passing 
> NULL at the moment:

You know, I've tracked a lot of this down previously when I submitted patches
to add vfsmount arguments to the vfs_ helpers, just to get tought by Al
that this is a bad idea :)

> fs/hpfs/namei.c
> 
> 	In hpfs_unlink, hpfs truncates one of its own inodes through
> 	notify_change(). You definitely don't want any lsms to interfere here,
> 	pathname based or not; hpfs should probably truncate its inode itself
> 	instead. But given that hpfs goes via the vfs, we at least pass NULL
> 	to indicate that this file really has no meaningful paths to it
> 	anymore. (In addition, we don't really have a vfsmount at this
> 	point anymore, and neither would it make sense to pass it there.)
> 
> 	To play more nicely with other lsms, hpfs could mark the inode as
> 	private before attempting the truncate.

The right fix would be to not go through the vfs.  Or even better to
remove the utter hack.  See my previous patch on this subject and the
discussion started on it.

> fs/reiserfs/xattr.c
> 
> 	The directories an files that reiserfs uses internally to store xattrs
> 	are hanging off ".reiserfs_priv/xattrs" in the filesystem. This part
> 	of the namespace is not accessible or visible from user space though
> 	except through the xattr syscalls.
> 
> 	Reiserfs should probably just mark all its xattr inodes as private in order
> 	to play nicely with other lsms. As far as pathname based lsms are concerned,
> 	pathnames to those fs-internal objects are meaningless though, and so we
> 	pass NULL here.

Well, the 100% correct fix would be to rip out the braindead reiserfs
xattr code :)
Of course that's not an option, but reiserfs would be much better of
stop using vfs_rmdir.  It really doesn't need most of the checks in there
and should just call into reiserfs_rmdir instead of doing this useless
trip into vfs land.

> fs/sysfs/file.c

> fs/nfsd/vfs.c and fs/nfsd/nfs4recover.c
> 
> 	For nfsd, the concept of pathnames is a bit peculiar. I'll try to respond to
> 	that separately.

the actually nfsd filehandle code is conceptually trivially fixable,
although with quite a bit of code churn.  As mention I'll soon submit
a patch for it.  nfs4recover.c is broken beyond repair and should just
be deleted from the tree.

  reply	other threads:[~2007-02-06  9:52 UTC|newest]

Thread overview: 61+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-02-05 18:22 Tony Jones
2007-02-05 18:22 ` [RFC 1/28] Pass struct vfsmount to the inode_create LSM hook Tony Jones
2007-02-05 18:22 ` [RFC 2/28] Remove redundant check from proc_setattr() Tony Jones
2007-02-05 19:16   ` Chris Wright
2007-02-05 18:22 ` [RFC 3/28] Pass struct file down to remove_suid and children Tony Jones
2007-02-05 18:22 ` [RFC 4/28] Add a vfsmount parameter to notify_change() Tony Jones
2007-02-05 18:23 ` [RFC 5/28] Pass struct vfsmount to the inode_setattr LSM hook Tony Jones
2007-02-05 18:23 ` [RFC 6/28] Add struct vfsmount parameter to vfs_mkdir() Tony Jones
2007-02-05 18:23 ` [RFC 7/28] Pass struct vfsmount to the inode_mkdir LSM hook Tony Jones
2007-02-05 18:23 ` [RFC 8/28] Add a struct vfsmount parameter to vfs_mknod() Tony Jones
2007-02-05 18:23 ` [RFC 9/28] Pass struct vfsmount to the inode_mknod LSM hook Tony Jones
2007-02-05 18:23 ` [RFC 10/28] Add a struct vfsmount parameter to vfs_symlink() Tony Jones
2007-02-05 18:23 ` [RFC 11/28] Pass struct vfsmount to the inode_symlink LSM hook Tony Jones
2007-02-05 18:24 ` [RFC 12/28] Pass struct vfsmount to the inode_readlink " Tony Jones
2007-02-05 18:24 ` [RFC 13/28] Add struct vfsmount parameters to vfs_link() Tony Jones
2007-02-05 18:24 ` [RFC 14/28] Pass struct vfsmount to the inode_link LSM hook Tony Jones
2007-02-05 18:24 ` [RFC 15/28] Add a struct vfsmount parameter to vfs_rmdir() Tony Jones
2007-02-05 18:24 ` [RFC 16/28] Pass struct vfsmount to the inode_rmdir LSM hook Tony Jones
2007-02-05 18:24 ` [RFC 17/28] Add a struct vfsmount parameter to vfs_unlink() Tony Jones
2007-02-05 18:25 ` [RFC 18/28] Pass struct vfsmount to the inode_unlink LSM hook Tony Jones
2007-02-05 18:25 ` [RFC 19/28] Add struct vfsmount parameters to vfs_rename() Tony Jones
2007-02-05 18:25 ` [RFC 20/28] Pass struct vfsmount to the inode_rename LSM hook Tony Jones
2007-02-05 18:25 ` [RFC 21/28] Add a struct vfsmount parameter to vfs_setxattr() Tony Jones
2007-02-05 18:25 ` [RFC 22/28] Pass struct vfsmount to the inode_setxattr LSM hook Tony Jones
2007-02-05 18:25 ` [RFC 23/28] Add a struct vfsmount parameter to vfs_getxattr() Tony Jones
2007-02-05 18:25 ` [RFC 24/28] Pass struct vfsmount to the inode_getxattr LSM hook Tony Jones
2007-02-05 18:26 ` [RFC 25/28] Add a struct vfsmount parameter to vfs_listxattr() Tony Jones
2007-02-05 18:26 ` [RFC 26/28] Pass struct vfsmount to the inode_listxattr LSM hook Tony Jones
2007-02-05 18:26 ` [RFC 27/28] Add a struct vfsmount parameter to vfs_removexattr() Tony Jones
2007-02-05 18:26 ` [RFC 28/28] Pass struct vfsmount to the inode_removexattr LSM hook Tony Jones
2007-02-05 18:44 ` [RFC 0/28] Patches to pass vfsmount to LSM inode security hooks Christoph Hellwig
2007-02-05 18:58   ` Trond Myklebust
2007-02-05 19:02     ` Christoph Hellwig
2007-02-06  3:20       ` Andreas Gruenbacher
2007-02-06  8:51         ` Trond Myklebust
2007-02-06  9:48           ` Christoph Hellwig
2007-02-06 10:31             ` Neil Brown
2007-02-07  9:25           ` Andreas Gruenbacher
2007-02-06  9:47         ` Christoph Hellwig
2007-02-06 10:26           ` Neil Brown
2007-02-06 10:37             ` Christoph Hellwig
2007-02-12 18:32               ` J. Bruce Fields
2007-02-07  9:58           ` Andreas Gruenbacher
2007-02-07 12:11             ` Christoph Hellwig
2007-02-05 19:15     ` Chris Wright
2007-02-06  0:44   ` Andreas Gruenbacher
2007-02-06  2:13   ` Andreas Gruenbacher
2007-02-06  9:52     ` Christoph Hellwig [this message]
2007-02-07  9:04       ` Andreas Gruenbacher
2007-02-06 12:55     ` Stephen Smalley
2007-02-07  8:55       ` Andreas Gruenbacher
2007-02-07 15:43         ` Chris Wright
2007-02-07 16:06           ` Stephen Smalley
2007-02-07 16:25           ` Jeff Mahoney
2007-02-07 19:55             ` Andreas Gruenbacher
2007-02-05 19:26 ` Casey Schaufler
2007-02-05 19:39   ` Arjan van de Ven
2007-02-05 19:50   ` Chris Wright
2007-02-05 20:23     ` Casey Schaufler
2007-02-06  2:30     ` Andreas Gruenbacher
2007-02-06 14:20     ` Tetsuo Handa

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