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

[Stephen Smalley <sds@tycho.nsa.gov>]

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@us.ibm.com>
> Signed-off-by: Kylene Hall <kjhall@us.ibm.com>
> --- 
>  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@us.ibm.com>
> + *	   Kylene Hall <kjhall@us.ibm.com>
> + *
> + *      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?

> +
> +static struct file_operations slm_level_ops = {
> +	.read = slm_read_level,
> +};
> +
> +int __init slm_init_secfs(void)
> +{
> +	if (!slim_enabled)
> +		return 0;
> +
> +	slim_sec_dir = securityfs_create_dir("slim", NULL);
> +	if (!slim_sec_dir || IS_ERR(slim_sec_dir))
> +		return -EFAULT;
> +	slim_level = securityfs_create_file("level", S_IRUGO,
> +					    slim_sec_dir, NULL, &slm_level_ops);
> +	if (!slim_level || IS_ERR(slim_level)) {
> +		securityfs_remove(slim_sec_dir);
> +		return -EFAULT;
> +	}
> +	return 0;
> +}
> +
> +__initcall(slm_init_secfs);
> +
> +void __exit slm_cleanup_secfs(void)
> +{
> +	securityfs_remove(slim_level);
> +	securityfs_remove(slim_sec_dir);
> +}
> +

-- 
Stephen Smalley
National Security Agency

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