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From: Ian Kent <raven@themaw.net>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Kernel Mailing List <linux-kernel@vger.kernel.org>,
	autofs mailing list <autofs@linux.kernel.org>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	Pavel Emelyanov <xemul@openvz.org>,
	"Eric W. Biederman" <ebiederm@xmission.com>
Subject: Re: [PATCH 3/4] autofs4 - track uid and gid of last mount requestor
Date: Thu, 28 Feb 2008 15:22:27 +0900	[thread overview]
Message-ID: <1204179747.3501.21.camel@raven.themaw.net> (raw)
In-Reply-To: <20080227204546.72e16e8d.akpm@linux-foundation.org>


On Wed, 2008-02-27 at 20:45 -0800, Andrew Morton wrote:
> On Tue, 26 Feb 2008 12:23:20 +0900 (WST) Ian Kent <raven@themaw.net> wrote:
> 
> > Hi Andrew,
> > 
> > Patch to track the uid and gid of the last process to request
> > a mount for on an autofs dentry.
> > 
> > Signed-off-by: Ian Kent < raven@themaw.net>
> > 
> > Ian
> > 
> > ---
> > diff -up linux-2.6.25-rc2-mm1/fs/autofs4/inode.c.track-last-mount-ids linux-2.6.25-rc2-mm1/fs/autofs4/inode.c
> > --- linux-2.6.25-rc2-mm1/fs/autofs4/inode.c.track-last-mount-ids	2008-02-20 13:11:28.000000000 +0900
> > +++ linux-2.6.25-rc2-mm1/fs/autofs4/inode.c	2008-02-20 13:12:23.000000000 +0900
> > @@ -43,6 +43,8 @@ struct autofs_info *autofs4_init_ino(str
> >  
> >  	ino->flags = 0;
> >  	ino->mode = mode;
> > +	ino->uid = 0;
> > +	ino->gid = 0;
> >  	ino->inode = NULL;
> >  	ino->dentry = NULL;
> >  	ino->size = 0;
> > diff -up linux-2.6.25-rc2-mm1/fs/autofs4/autofs_i.h.track-last-mount-ids linux-2.6.25-rc2-mm1/fs/autofs4/autofs_i.h
> > --- linux-2.6.25-rc2-mm1/fs/autofs4/autofs_i.h.track-last-mount-ids	2008-02-20 13:14:03.000000000 +0900
> > +++ linux-2.6.25-rc2-mm1/fs/autofs4/autofs_i.h	2008-02-20 13:14:34.000000000 +0900
> > @@ -58,6 +58,9 @@ struct autofs_info {
> >  	unsigned long last_used;
> >  	atomic_t count;
> >  
> > +	uid_t uid;
> > +	gid_t gid;
> > +
> >  	mode_t	mode;
> >  	size_t	size;
> >  
> > diff -up linux-2.6.25-rc2-mm1/fs/autofs4/waitq.c.track-last-mount-ids linux-2.6.25-rc2-mm1/fs/autofs4/waitq.c
> > --- linux-2.6.25-rc2-mm1/fs/autofs4/waitq.c.track-last-mount-ids	2008-02-20 13:06:20.000000000 +0900
> > +++ linux-2.6.25-rc2-mm1/fs/autofs4/waitq.c	2008-02-20 13:10:23.000000000 +0900
> > @@ -363,6 +363,38 @@ int autofs4_wait(struct autofs_sb_info *
> >  
> >  	status = wq->status;
> >  
> > +	/*
> > +	 * For direct and offset mounts we need to track the requestor
> > +	 * uid and gid in the dentry info struct. This is so it can be
> > +	 * supplied, on request, by the misc device ioctl interface.
> > +	 * This is needed during daemon resatart when reconnecting
> > +	 * to existing, active, autofs mounts. The uid and gid (and
> > +	 * related string values) may be used for macro substitution
> > +	 * in autofs mount maps.
> > +	 */
> > +	if (!status) {
> > +		struct dentry *de = NULL;
> > +
> > +		/* direct mount or browsable map */
> > +		ino = autofs4_dentry_ino(dentry);
> > +		if (!ino) {
> > +			/* If not lookup actual dentry used */
> > +			de = d_lookup(dentry->d_parent, &dentry->d_name);
> > +			ino = autofs4_dentry_ino(de);
> > +		}
> > +
> > +		/* Set mount requestor */
> > +		if (ino) {
> > +			if (ino) {
> > +				ino->uid = wq->uid;
> > +				ino->gid = wq->gid;
> > +			}
> > +		}
> > +
> > +		if (de)
> > +			dput(de);
> > +	}
> > +
> 
> But uids and gids are no longer system-wide-unique.  Two different users
> can have the same identifiers in different namespaces.  What happens then?

That's a tricky question.

Presumably, the process requesting the mount has the user space daemon
running in the namespace within which the uid and gid are to be looked
up, by the daemon.

Am I missing something?

Ian



  reply	other threads:[~2008-02-28  6:25 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-26  3:21 [PATCH 0/4] autofs4 - autofs needs a miscelaneous device for ioctls Ian Kent
2008-02-26  3:22 ` [PATCH 1/4] autofs4 - check for invalid dentry in getpath Ian Kent
2008-02-26  3:23 ` [PATCH 3/4] autofs4 - track uid and gid of last mount requestor Ian Kent
2008-02-26  5:14   ` [PATCH 3/4] autofs4 - track uid and gid of last mount requestor - correction Ian Kent
2008-02-28  4:45   ` [PATCH 3/4] autofs4 - track uid and gid of last mount requestor Andrew Morton
2008-02-28  6:22     ` Ian Kent [this message]
2008-02-28  6:37       ` Andrew Morton
2008-02-28  7:08         ` Ian Kent
2008-02-28  7:23           ` Andrew Morton
2008-02-28  8:00             ` Ian Kent
2008-02-28 17:13               ` Jeff Moyer
2008-02-28 19:51                 ` Serge E. Hallyn
2008-02-29  3:32                   ` Ian Kent
2008-02-29 16:09                     ` Serge E. Hallyn
2008-02-29 16:20                       ` Pavel Emelyanov
2008-02-29 17:42                         ` Serge E. Hallyn
2008-03-02  0:49                       ` Eric W. Biederman
2008-03-02  1:13                       ` Eric W. Biederman
2008-03-03 15:28                         ` Serge E. Hallyn
2008-03-04 22:16                           ` Eric W. Biederman
2008-02-28  7:51           ` Pavel Emelyanov
2008-02-28  7:59             ` Andrew Morton
2008-02-28  8:06               ` Ian Kent
2008-02-28 12:31                 ` [autofs] " Fabio Olive Leite
2008-02-28 20:33             ` Eric W. Biederman
2008-02-26  3:23 ` [PATCH 4/4] autofs4 - add miscelaneous device for ioctls Ian Kent
2008-02-28  5:17   ` Andrew Morton
2008-02-28  6:18     ` Ian Kent
2008-03-13  7:00       ` [RFC] " Ian Kent
2008-03-14  2:45         ` Ian Kent
2008-03-14 12:45         ` Thomas Graf
2008-03-14 14:10           ` Ian Kent
2008-02-29 16:24     ` Ian Kent
2008-04-11  7:02       ` Ian Kent
2008-04-12  4:03         ` Andrew Morton
2008-04-14  4:45           ` Ian Kent
2008-02-26  4:29 ` [PATCH 2/4] autofs4 - add mount option to display mount device Ian Kent
2008-02-28  5:17   ` Andrew Morton
2008-02-28  4:40 ` [PATCH 0/4] autofs4 - autofs needs a miscelaneous device for ioctls Andrew Morton
2008-02-28  6:07   ` Ian Kent

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