Re: [PATCH 4/7] SLIM: secfs patch

From: Stephen Smalley
Date: Wed Sep 27 2006 - 08:29:49 EST


On Mon, 2006-09-18 at 13:50 -0700, Kylene Jo Hall wrote:
> On Mon, 2006-09-18 at 16:30 -0400, Stephen Smalley wrote:
> > On Tue, 2006-09-12 at 10:57 -0700, Kylene Jo Hall wrote:
> > > This patch provides the securityfs used by SLIM.
> > >
> > > Signed-off-by: Mimi Zohar <zohar@xxxxxxxxxx>
> > > Signed-off-by: Kylene Hall <kjhall@xxxxxxxxxx>
> > > ---
> > > security/slim/slm_secfs.c | 73 ++++++++++++++++++++++++++++++++++++
> > > 1 files changed, 73 insertions(+)
> > >
> > > --- linux-2.6.18/security/slim/slm_secfs.c 1969-12-31 16:00:00.000000000 -0800
> > > +++ linux-2.6.17-working/security/slim/slm_secfs.c 2006-09-06 11:49:09.000000000 -0700
> > > @@ -0,0 +1,73 @@
> > > +/*
> > > + * SLIM securityfs support: debugging control files
> > > + *
> > > + * Copyright (C) 2005, 2006 IBM Corporation
> > > + * Author: Mimi Zohar <zohar@xxxxxxxxxx>
> > > + * Kylene Hall <kjhall@xxxxxxxxxx>
> > > + *
> > > + * This program is free software; you can redistribute it and/or modify
> > > + * it under the terms of the GNU General Public License as published by
> > > + * the Free Software Foundation, version 2 of the License.
> > > + */
> > > +
> > > +#include <asm/uaccess.h>
> > > +#include <linux/config.h>
> > > +#include <linux/module.h>
> > > +#include <linux/kernel.h>
> > > +#include <linux/security.h>
> > > +#include <linux/debugfs.h>
> > > +#include "slim.h"
> > > +
> > > +static struct dentry *slim_sec_dir, *slim_level;
> > > +
> > > +static ssize_t slm_read_level(struct file *file, char __user *buf,
> > > + size_t buflen, loff_t *ppos)
> > > +{
> > > + struct slm_tsec_data *cur_tsec = current->security;
> > > + ssize_t len;
> > > + char data[28];
> > > + if (is_kernel_thread(current))
> > > + len = snprintf(data, sizeof(data), "KERNEL\n");
> > > + else if (!cur_tsec)
> > > + len = snprintf(data, sizeof(data), "UNKNOWN\n");
> > > + else {
> > > + if (cur_tsec->iac_wx != cur_tsec->iac_r)
> > > + len = snprintf(data, sizeof(data), "GUARD wx:%s r:%s\n",
> > > + slm_iac_str[cur_tsec->iac_wx],
> > > + slm_iac_str[cur_tsec->iac_r]);
> > > + else
> > > + len = snprintf(data, sizeof(data), "%s\n",
> > > + slm_iac_str[cur_tsec->iac_wx]);
> > > + }
> > > + return simple_read_from_buffer(buf, buflen, ppos, data, len);
> > > +}
> >
> > Why do you need this when you implement getprocattr and return the same
> > data that way?
> >
> True you can get the same info that way but we find it very useful to be
> able to cat this file and get the level of the current process.

It is duplicated code and interface for no obvious purpose - why cannot
you cat /proc/self/attr/current instead?

--
Stephen Smalley
National Security Agency

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