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From: Al Viro <viro@ZenIV.linux.org.uk>
To: john.johansen@canonical.com
Cc: linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org
Subject: Re: [PATCH 01/12] Miscellaneous functions and defines needed by AppArmor, including the base path resolution routines.
Date: Fri, 19 Feb 2010 11:03:21 +0000	[thread overview]
Message-ID: <20100219110320.GL30031@ZenIV.linux.org.uk> (raw)
In-Reply-To: <1266572188-26529-2-git-send-email-john.johansen@canonical.com>

On Fri, Feb 19, 2010 at 01:36:17AM -0800, john.johansen@canonical.com wrote:

> +static int d_namespace_path(struct path *path, char *buf, int buflen,
> +			    char **name, int flags)
> +{
> +	struct path root, tmp, ns_root = { };
> +	char *res;
> +	int deleted, connected;
> +	int error = 0;
> +
> +	read_lock(&current->fs->lock);
> +	root = current->fs->root;
> +	/* released below */
> +	path_get(&root);
> +	read_unlock(&current->fs->lock);
> +
> +	spin_lock(&vfsmount_lock);
> +	if (root.mnt && root.mnt->mnt_ns)
> +		/* released below */
> +		ns_root.mnt = mntget(root.mnt->mnt_ns->root);
> +	if (ns_root.mnt)
> +		/* released below */
> +		ns_root.dentry = dget(ns_root.mnt->mnt_root);
> +	spin_unlock(&vfsmount_lock);

Junk.  You might as well leave ns_root {NULL, NULL} instead of that crap.

> +	spin_lock(&dcache_lock);
> +	/* There is a race window between path lookup here and the
> +	 * need to strip the " (deleted) string that __d_path applies
> +	 * Detect the race and relookup the path
> +	 *
> +	 * The stripping of (deleted) is a hack that could be removed
> +	 * with an updated __d_path

Yes, it could.  Where's the patch doing just that?  Or discussion of
desired interface, at lease...

> +	if (flags & PATH_CHROOT_REL)
> +		connected = tmp.dentry == root.dentry && tmp.mnt == root.mnt;
> +	else
> +		connected = tmp.dentry == ns_root.dentry &&
> +			tmp.mnt == ns_root.mnt;
> +
> +	if (!connected && 
> +	    !(flags & PATH_CONNECT_PATH) &&
> +	    !((flags & PATH_CHROOT_REL) && (flags & PATH_CHROOT_NSCONNECT) &&
> +	      (tmp.dentry == ns_root.dentry && tmp.mnt == ns_root.mnt))) {
> +		/* disconnected path, don't return pathname starting with '/' */
> +		error = -ESTALE;
> +		if (*res == '/')
> +			*name = res + 1;

Explanations, please.

  reply	other threads:[~2010-02-19 11:03 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-02-19  9:36 [AppArmor #4 0/12] AppArmor security module john.johansen
2010-02-19  9:36 ` [PATCH 01/12] Miscellaneous functions and defines needed by AppArmor, including the base path resolution routines john.johansen
2010-02-19 11:03   ` Al Viro [this message]
2010-02-20 12:17     ` John Johansen
2010-02-20 17:25       ` John Johansen
2010-02-20 19:10         ` John Johansen
2010-02-20 12:24     ` John Johansen
2010-02-19  9:36 ` [PATCH 02/12] Update kenel audit range comments to show AppArmor's registered range of 1500-1599. This range used to be reserved for LSPP but LSPP uses the SELinux range and the range was given to AppArmor. Patch is not in mainline -- pending AppArmor code submission to lkml john.johansen
2010-02-19  9:36 ` [PATCH 03/12] AppArmor contexts attach profiles and state to tasks, files, etc. when a direct profile reference is not sufficient john.johansen
2010-02-19  9:36 ` [PATCH 04/12] The basic routines and defines for AppArmor policy. AppArmor policy is defined by a few basic components. profiles - the basic unit of confinement contain all the information to enforce policy on a task john.johansen
2010-02-19  9:36 ` [PATCH 05/12] A basic dfa matching engine based off the dfa engine in the Dragon Book. It uses simple row comb compression with a check field john.johansen
2010-02-19  9:36 ` [PATCH 06/12] AppArmor policy is loaded in a platform independent flattened binary stream. Verify and unpack the data converting it to the internal format needed for enforcement john.johansen
2010-02-19  9:36 ` [PATCH 07/12] AppArmor /proc/<pid>/attr/* and apparmorfs interfaces to userspace john.johansen
2010-02-19  9:36 ` [PATCH 08/12] AppArmor: file enforcement routines john.johansen
2010-02-19  9:36 ` [PATCH 09/12] AppArmor ipc, rlimit, network and capability routines john.johansen
2010-02-19  9:36 ` [PATCH 10/12] AppArmor routines for controlling domain transitions john.johansen
2010-02-19  9:36 ` [PATCH 11/12] AppArmor hooks to interface with the LSM, module parameters and initialization john.johansen
2010-02-22 22:14   ` Serge E. Hallyn
2010-02-23  7:58     ` John Johansen
2010-02-19  9:36 ` [PATCH 12/12] Kconfig and Makefiles to enable configuration and building of AppArmor john.johansen
2010-02-22 22:16   ` Serge E. Hallyn
2010-02-23  7:45     ` John Johansen
2010-03-03  7:50       ` Kees Cook
2010-02-23  1:59 ` [AppArmor #4 0/12] AppArmor security module Tetsuo Handa
2010-02-23  8:38   ` John Johansen
2010-02-23  8:31 ` Tetsuo Handa
2010-02-23  9:17   ` John Johansen
2010-02-26  3:22 ` Tetsuo Handa
2010-02-26  6:31 ` Tetsuo Handa

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