smackfs.c 29.0 KB
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/*
 * Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.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.
 *
 * Authors:
 * 	Casey Schaufler <casey@schaufler-ca.com>
 * 	Ahmed S. Darwish <darwish.07@gmail.com>
 *
 * Special thanks to the authors of selinuxfs.
 *
 *	Karl MacMillan <kmacmillan@tresys.com>
 *	James Morris <jmorris@redhat.com>
 *
 */

#include <linux/kernel.h>
#include <linux/vmalloc.h>
#include <linux/security.h>
#include <linux/mutex.h>
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#include <net/net_namespace.h>
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#include <net/netlabel.h>
#include <net/cipso_ipv4.h>
#include <linux/seq_file.h>
#include <linux/ctype.h>
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#include <linux/audit.h>
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#include "smack.h"

/*
 * smackfs pseudo filesystem.
 */

enum smk_inos {
	SMK_ROOT_INO	= 2,
	SMK_LOAD	= 3,	/* load policy */
	SMK_CIPSO	= 4,	/* load label -> CIPSO mapping */
	SMK_DOI		= 5,	/* CIPSO DOI */
	SMK_DIRECT	= 6,	/* CIPSO level indicating direct label */
	SMK_AMBIENT	= 7,	/* internet ambient label */
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	SMK_NETLBLADDR	= 8,	/* single label hosts */
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	SMK_ONLYCAP	= 9,	/* the only "capable" label */
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};

/*
 * List locks
 */
static DEFINE_MUTEX(smack_list_lock);
static DEFINE_MUTEX(smack_cipso_lock);
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static DEFINE_MUTEX(smack_ambient_lock);
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static DEFINE_MUTEX(smk_netlbladdr_lock);
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/*
 * This is the "ambient" label for network traffic.
 * If it isn't somehow marked, use this.
 * It can be reset via smackfs/ambient
 */
char *smack_net_ambient = smack_known_floor.smk_known;

/*
 * This is the level in a CIPSO header that indicates a
 * smack label is contained directly in the category set.
 * It can be reset via smackfs/direct
 */
int smack_cipso_direct = SMACK_CIPSO_DIRECT_DEFAULT;

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/*
 * Unless a process is running with this label even
 * having CAP_MAC_OVERRIDE isn't enough to grant
 * privilege to violate MAC policy. If no label is
 * designated (the NULL case) capabilities apply to
 * everyone. It is expected that the hat (^) label
 * will be used if any label is used.
 */
char *smack_onlycap;

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/*
 * Certain IP addresses may be designated as single label hosts.
 * Packets are sent there unlabeled, but only from tasks that
 * can write to the specified label.
 */
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LIST_HEAD(smk_netlbladdr_list);
LIST_HEAD(smack_rule_list);
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static int smk_cipso_doi_value = SMACK_CIPSO_DOI_DEFAULT;

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const char *smack_cipso_option = SMACK_CIPSO_OPTION;


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#define	SEQ_READ_FINISHED	1

/*
 * Values for parsing cipso rules
 * SMK_DIGITLEN: Length of a digit field in a rule.
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 * SMK_CIPSOMIN: Minimum possible cipso rule length.
 * SMK_CIPSOMAX: Maximum possible cipso rule length.
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 */
#define SMK_DIGITLEN 4
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#define SMK_CIPSOMIN (SMK_LABELLEN + 2 * SMK_DIGITLEN)
#define SMK_CIPSOMAX (SMK_CIPSOMIN + SMACK_CIPSO_MAXCATNUM * SMK_DIGITLEN)

/*
 * Values for parsing MAC rules
 * SMK_ACCESS: Maximum possible combination of access permissions
 * SMK_ACCESSLEN: Maximum length for a rule access field
 * SMK_LOADLEN: Smack rule length
 */
#define SMK_ACCESS    "rwxa"
#define SMK_ACCESSLEN (sizeof(SMK_ACCESS) - 1)
#define SMK_LOADLEN   (SMK_LABELLEN + SMK_LABELLEN + SMK_ACCESSLEN)

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/**
 * smk_netlabel_audit_set - fill a netlbl_audit struct
 * @nap: structure to fill
 */
static void smk_netlabel_audit_set(struct netlbl_audit *nap)
{
	nap->loginuid = audit_get_loginuid(current);
	nap->sessionid = audit_get_sessionid(current);
	nap->secid = smack_to_secid(current_security());
}

/*
 * Values for parsing single label host rules
 * "1.2.3.4 X"
 * "192.168.138.129/32 abcdefghijklmnopqrstuvw"
 */
#define SMK_NETLBLADDRMIN	9
#define SMK_NETLBLADDRMAX	42
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/*
 * Seq_file read operations for /smack/load
 */

static void *load_seq_start(struct seq_file *s, loff_t *pos)
{
	if (*pos == SEQ_READ_FINISHED)
		return NULL;
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	if (list_empty(&smack_rule_list))
		return NULL;
	return smack_rule_list.next;
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}

static void *load_seq_next(struct seq_file *s, void *v, loff_t *pos)
{
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	struct list_head *list = v;
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	if (list_is_last(list, &smack_rule_list)) {
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		*pos = SEQ_READ_FINISHED;
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		return NULL;
	}
	return list->next;
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}

static int load_seq_show(struct seq_file *s, void *v)
{
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	struct list_head *list = v;
	struct smack_rule *srp =
		 list_entry(list, struct smack_rule, list);
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	seq_printf(s, "%s %s", (char *)srp->smk_subject,
		   (char *)srp->smk_object);

	seq_putc(s, ' ');

	if (srp->smk_access & MAY_READ)
		seq_putc(s, 'r');
	if (srp->smk_access & MAY_WRITE)
		seq_putc(s, 'w');
	if (srp->smk_access & MAY_EXEC)
		seq_putc(s, 'x');
	if (srp->smk_access & MAY_APPEND)
		seq_putc(s, 'a');
	if (srp->smk_access == 0)
		seq_putc(s, '-');

	seq_putc(s, '\n');

	return 0;
}

static void load_seq_stop(struct seq_file *s, void *v)
{
	/* No-op */
}

static struct seq_operations load_seq_ops = {
	.start = load_seq_start,
	.next  = load_seq_next,
	.show  = load_seq_show,
	.stop  = load_seq_stop,
};

/**
 * smk_open_load - open() for /smack/load
 * @inode: inode structure representing file
 * @file: "load" file pointer
 *
 * For reading, use load_seq_* seq_file reading operations.
 */
static int smk_open_load(struct inode *inode, struct file *file)
{
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	return seq_open(file, &load_seq_ops);
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}

/**
 * smk_set_access - add a rule to the rule list
 * @srp: the new rule to add
 *
 * Looks through the current subject/object/access list for
 * the subject/object pair and replaces the access that was
 * there. If the pair isn't found add it with the specified
 * access.
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 *
 * Returns 0 if nothing goes wrong or -ENOMEM if it fails
 * during the allocation of the new pair to add.
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 */
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static int smk_set_access(struct smack_rule *srp)
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{
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	struct smack_rule *sp;
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	int ret = 0;
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	int found;
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	mutex_lock(&smack_list_lock);

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	found = 0;
	list_for_each_entry_rcu(sp, &smack_rule_list, list) {
		if (sp->smk_subject == srp->smk_subject &&
		    sp->smk_object == srp->smk_object) {
			found = 1;
			sp->smk_access = srp->smk_access;
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			break;
		}
	}
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	if (found == 0)
		list_add_rcu(&srp->list, &smack_rule_list);
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	mutex_unlock(&smack_list_lock);

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	return ret;
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}

/**
 * smk_write_load - write() for /smack/load
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 * @file: file pointer, not actually used
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 * @buf: where to get the data from
 * @count: bytes sent
 * @ppos: where to start - must be 0
 *
 * Get one smack access rule from above.
 * The format is exactly:
 *     char subject[SMK_LABELLEN]
 *     char object[SMK_LABELLEN]
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 *     char access[SMK_ACCESSLEN]
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 *
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 * writes must be SMK_LABELLEN+SMK_LABELLEN+SMK_ACCESSLEN bytes.
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 */
static ssize_t smk_write_load(struct file *file, const char __user *buf,
			      size_t count, loff_t *ppos)
{
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	struct smack_rule *rule;
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	char *data;
	int rc = -EINVAL;

	/*
	 * Must have privilege.
	 * No partial writes.
	 * Enough data must be present.
	 */
	if (!capable(CAP_MAC_ADMIN))
		return -EPERM;
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	if (*ppos != 0 || count != SMK_LOADLEN)
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		return -EINVAL;

	data = kzalloc(count, GFP_KERNEL);
	if (data == NULL)
		return -ENOMEM;

	if (copy_from_user(data, buf, count) != 0) {
		rc = -EFAULT;
		goto out;
	}

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	rule = kzalloc(sizeof(*rule), GFP_KERNEL);
	if (rule == NULL) {
		rc = -ENOMEM;
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		goto out;
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	}
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	rule->smk_subject = smk_import(data, 0);
	if (rule->smk_subject == NULL)
		goto out_free_rule;
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	rule->smk_object = smk_import(data + SMK_LABELLEN, 0);
	if (rule->smk_object == NULL)
		goto out_free_rule;

	rule->smk_access = 0;
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	switch (data[SMK_LABELLEN + SMK_LABELLEN]) {
	case '-':
		break;
	case 'r':
	case 'R':
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		rule->smk_access |= MAY_READ;
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		break;
	default:
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		goto out_free_rule;
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	}

	switch (data[SMK_LABELLEN + SMK_LABELLEN + 1]) {
	case '-':
		break;
	case 'w':
	case 'W':
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		rule->smk_access |= MAY_WRITE;
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		break;
	default:
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		goto out_free_rule;
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	}

	switch (data[SMK_LABELLEN + SMK_LABELLEN + 2]) {
	case '-':
		break;
	case 'x':
	case 'X':
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		rule->smk_access |= MAY_EXEC;
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		break;
	default:
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		goto out_free_rule;
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	}

	switch (data[SMK_LABELLEN + SMK_LABELLEN + 3]) {
	case '-':
		break;
	case 'a':
	case 'A':
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		rule->smk_access |= MAY_APPEND;
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		break;
	default:
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		goto out_free_rule;
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	}

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	rc = smk_set_access(rule);
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	if (!rc)
		rc = count;
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	goto out;
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out_free_rule:
	kfree(rule);
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out:
	kfree(data);
	return rc;
}

static const struct file_operations smk_load_ops = {
	.open           = smk_open_load,
	.read		= seq_read,
	.llseek         = seq_lseek,
	.write		= smk_write_load,
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	.release        = seq_release,
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};

/**
 * smk_cipso_doi - initialize the CIPSO domain
 */
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static void smk_cipso_doi(void)
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{
	int rc;
	struct cipso_v4_doi *doip;
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	struct netlbl_audit nai;
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	smk_netlabel_audit_set(&nai);
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	rc = netlbl_cfg_map_del(NULL, PF_INET, NULL, NULL, &nai);
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	if (rc != 0)
		printk(KERN_WARNING "%s:%d remove rc = %d\n",
		       __func__, __LINE__, rc);

	doip = kmalloc(sizeof(struct cipso_v4_doi), GFP_KERNEL);
	if (doip == NULL)
		panic("smack:  Failed to initialize cipso DOI.\n");
	doip->map.std = NULL;
	doip->doi = smk_cipso_doi_value;
	doip->type = CIPSO_V4_MAP_PASS;
	doip->tags[0] = CIPSO_V4_TAG_RBITMAP;
	for (rc = 1; rc < CIPSO_V4_TAG_MAXCNT; rc++)
		doip->tags[rc] = CIPSO_V4_TAG_INVALID;

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	rc = netlbl_cfg_cipsov4_add(doip, &nai);
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	if (rc != 0) {
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		printk(KERN_WARNING "%s:%d cipso add rc = %d\n",
		       __func__, __LINE__, rc);
		kfree(doip);
		return;
	}
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	rc = netlbl_cfg_cipsov4_map_add(doip->doi, NULL, NULL, NULL, &nai);
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	if (rc != 0) {
		printk(KERN_WARNING "%s:%d map add rc = %d\n",
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		       __func__, __LINE__, rc);
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		kfree(doip);
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		return;
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	}
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}

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/**
 * smk_unlbl_ambient - initialize the unlabeled domain
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 * @oldambient: previous domain string
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 */
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static void smk_unlbl_ambient(char *oldambient)
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{
	int rc;
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	struct netlbl_audit nai;
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	smk_netlabel_audit_set(&nai);
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	if (oldambient != NULL) {
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		rc = netlbl_cfg_map_del(oldambient, PF_INET, NULL, NULL, &nai);
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		if (rc != 0)
			printk(KERN_WARNING "%s:%d remove rc = %d\n",
			       __func__, __LINE__, rc);
	}

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	rc = netlbl_cfg_unlbl_map_add(smack_net_ambient, PF_INET,
				      NULL, NULL, &nai);
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	if (rc != 0)
		printk(KERN_WARNING "%s:%d add rc = %d\n",
		       __func__, __LINE__, rc);
}

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/*
 * Seq_file read operations for /smack/cipso
 */

static void *cipso_seq_start(struct seq_file *s, loff_t *pos)
{
	if (*pos == SEQ_READ_FINISHED)
		return NULL;
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	if (list_empty(&smack_known_list))
		return NULL;
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	return smack_known_list.next;
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}

static void *cipso_seq_next(struct seq_file *s, void *v, loff_t *pos)
{
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	struct list_head  *list = v;
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	/*
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	 * labels with no associated cipso value wont be printed
	 * in cipso_seq_show
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	 */
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	if (list_is_last(list, &smack_known_list)) {
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		*pos = SEQ_READ_FINISHED;
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		return NULL;
	}
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	return list->next;
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}

/*
 * Print cipso labels in format:
 * label level[/cat[,cat]]
 */
static int cipso_seq_show(struct seq_file *s, void *v)
{
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	struct list_head  *list = v;
	struct smack_known *skp =
		 list_entry(list, struct smack_known, list);
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	struct smack_cipso *scp = skp->smk_cipso;
	char *cbp;
	char sep = '/';
	int cat = 1;
	int i;
	unsigned char m;

	if (scp == NULL)
		return 0;

	seq_printf(s, "%s %3d", (char *)&skp->smk_known, scp->smk_level);

	cbp = scp->smk_catset;
	for (i = 0; i < SMK_LABELLEN; i++)
		for (m = 0x80; m != 0; m >>= 1) {
			if (m & cbp[i]) {
				seq_printf(s, "%c%d", sep, cat);
				sep = ',';
			}
			cat++;
		}

	seq_putc(s, '\n');

	return 0;
}

static void cipso_seq_stop(struct seq_file *s, void *v)
{
	/* No-op */
}

static struct seq_operations cipso_seq_ops = {
	.start = cipso_seq_start,
	.stop  = cipso_seq_stop,
	.next  = cipso_seq_next,
	.show  = cipso_seq_show,
};

/**
 * smk_open_cipso - open() for /smack/cipso
 * @inode: inode structure representing file
 * @file: "cipso" file pointer
 *
 * Connect our cipso_seq_* operations with /smack/cipso
 * file_operations
 */
static int smk_open_cipso(struct inode *inode, struct file *file)
{
	return seq_open(file, &cipso_seq_ops);
}

/**
 * smk_write_cipso - write() for /smack/cipso
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 * @file: file pointer, not actually used
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 * @buf: where to get the data from
 * @count: bytes sent
 * @ppos: where to start
 *
 * Accepts only one cipso rule per write call.
 * Returns number of bytes written or error code, as appropriate
 */
static ssize_t smk_write_cipso(struct file *file, const char __user *buf,
			       size_t count, loff_t *ppos)
{
	struct smack_known *skp;
	struct smack_cipso *scp = NULL;
	char mapcatset[SMK_LABELLEN];
	int maplevel;
	int cat;
	int catlen;
	ssize_t rc = -EINVAL;
	char *data = NULL;
	char *rule;
	int ret;
	int i;

	/*
	 * Must have privilege.
	 * No partial writes.
	 * Enough data must be present.
	 */
	if (!capable(CAP_MAC_ADMIN))
		return -EPERM;
	if (*ppos != 0)
		return -EINVAL;
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	if (count < SMK_CIPSOMIN || count > SMK_CIPSOMAX)
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		return -EINVAL;

	data = kzalloc(count + 1, GFP_KERNEL);
	if (data == NULL)
		return -ENOMEM;

	if (copy_from_user(data, buf, count) != 0) {
		rc = -EFAULT;
		goto unlockedout;
	}

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	/* labels cannot begin with a '-' */
	if (data[0] == '-') {
		rc = -EINVAL;
		goto unlockedout;
	}
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	data[count] = '\0';
	rule = data;
	/*
	 * Only allow one writer at a time. Writes should be
	 * quite rare and small in any case.
	 */
	mutex_lock(&smack_cipso_lock);

	skp = smk_import_entry(rule, 0);
	if (skp == NULL)
		goto out;

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	rule += SMK_LABELLEN;
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	ret = sscanf(rule, "%d", &maplevel);
	if (ret != 1 || maplevel > SMACK_CIPSO_MAXLEVEL)
		goto out;

	rule += SMK_DIGITLEN;
	ret = sscanf(rule, "%d", &catlen);
	if (ret != 1 || catlen > SMACK_CIPSO_MAXCATNUM)
		goto out;

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	if (count != (SMK_CIPSOMIN + catlen * SMK_DIGITLEN))
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		goto out;

	memset(mapcatset, 0, sizeof(mapcatset));

	for (i = 0; i < catlen; i++) {
		rule += SMK_DIGITLEN;
		ret = sscanf(rule, "%d", &cat);
		if (ret != 1 || cat > SMACK_CIPSO_MAXCATVAL)
			goto out;

		smack_catset_bit(cat, mapcatset);
	}

	if (skp->smk_cipso == NULL) {
		scp = kzalloc(sizeof(struct smack_cipso), GFP_KERNEL);
		if (scp == NULL) {
			rc = -ENOMEM;
			goto out;
		}
	}

	spin_lock_bh(&skp->smk_cipsolock);

	if (scp == NULL)
		scp = skp->smk_cipso;
	else
		skp->smk_cipso = scp;

	scp->smk_level = maplevel;
	memcpy(scp->smk_catset, mapcatset, sizeof(mapcatset));

	spin_unlock_bh(&skp->smk_cipsolock);

	rc = count;
out:
	mutex_unlock(&smack_cipso_lock);
unlockedout:
	kfree(data);
	return rc;
}

static const struct file_operations smk_cipso_ops = {
	.open           = smk_open_cipso,
	.read		= seq_read,
	.llseek         = seq_lseek,
	.write		= smk_write_cipso,
	.release        = seq_release,
};

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/*
 * Seq_file read operations for /smack/netlabel
 */

static void *netlbladdr_seq_start(struct seq_file *s, loff_t *pos)
{
	if (*pos == SEQ_READ_FINISHED)
		return NULL;
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	if (list_empty(&smk_netlbladdr_list))
		return NULL;
	return smk_netlbladdr_list.next;
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}

static void *netlbladdr_seq_next(struct seq_file *s, void *v, loff_t *pos)
{
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	struct list_head *list = v;
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665
	if (list_is_last(list, &smk_netlbladdr_list)) {
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		*pos = SEQ_READ_FINISHED;
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		return NULL;
	}
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	return list->next;
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}
#define BEBITS	(sizeof(__be32) * 8)

/*
 * Print host/label pairs
 */
static int netlbladdr_seq_show(struct seq_file *s, void *v)
{
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	struct list_head *list = v;
	struct smk_netlbladdr *skp =
			 list_entry(list, struct smk_netlbladdr, list);
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	unsigned char *hp = (char *) &skp->smk_host.sin_addr.s_addr;
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	int maskn;
	u32 temp_mask = be32_to_cpu(skp->smk_mask.s_addr);
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686
	for (maskn = 0; temp_mask; temp_mask <<= 1, maskn++);
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	seq_printf(s, "%u.%u.%u.%u/%d %s\n",
		hp[0], hp[1], hp[2], hp[3], maskn, skp->smk_label);

	return 0;
}

static void netlbladdr_seq_stop(struct seq_file *s, void *v)
{
	/* No-op */
}

static struct seq_operations netlbladdr_seq_ops = {
	.start = netlbladdr_seq_start,
	.stop  = netlbladdr_seq_stop,
	.next  = netlbladdr_seq_next,
	.show  = netlbladdr_seq_show,
};

/**
 * smk_open_netlbladdr - open() for /smack/netlabel
 * @inode: inode structure representing file
 * @file: "netlabel" file pointer
 *
 * Connect our netlbladdr_seq_* operations with /smack/netlabel
 * file_operations
 */
static int smk_open_netlbladdr(struct inode *inode, struct file *file)
{
	return seq_open(file, &netlbladdr_seq_ops);
}

719 720 721 722 723 724
/**
 * smk_netlbladdr_insert
 * @new : netlabel to insert
 *
 * This helper insert netlabel in the smack_netlbladdrs list
 * sorted by netmask length (longest to smallest)
725 726
 * locked by &smk_netlbladdr_lock in smk_write_netlbladdr
 *
727 728 729
 */
static void smk_netlbladdr_insert(struct smk_netlbladdr *new)
{
730
	struct smk_netlbladdr *m, *m_next;
731

732 733
	if (list_empty(&smk_netlbladdr_list)) {
		list_add_rcu(&new->list, &smk_netlbladdr_list);
734 735 736
		return;
	}

737 738 739
	m = list_entry(rcu_dereference(smk_netlbladdr_list.next),
			 struct smk_netlbladdr, list);

740
	/* the comparison '>' is a bit hacky, but works */
741 742
	if (new->smk_mask.s_addr > m->smk_mask.s_addr) {
		list_add_rcu(&new->list, &smk_netlbladdr_list);
743 744
		return;
	}
745 746 747 748

	list_for_each_entry_rcu(m, &smk_netlbladdr_list, list) {
		if (list_is_last(&m->list, &smk_netlbladdr_list)) {
			list_add_rcu(&new->list, &m->list);
749 750
			return;
		}
751 752 753 754
		m_next = list_entry(rcu_dereference(m->list.next),
				 struct smk_netlbladdr, list);
		if (new->smk_mask.s_addr > m_next->smk_mask.s_addr) {
			list_add_rcu(&new->list, &m->list);
755 756 757 758 759 760
			return;
		}
	}
}


761 762
/**
 * smk_write_netlbladdr - write() for /smack/netlabel
763
 * @file: file pointer, not actually used
764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783
 * @buf: where to get the data from
 * @count: bytes sent
 * @ppos: where to start
 *
 * Accepts only one netlbladdr per write call.
 * Returns number of bytes written or error code, as appropriate
 */
static ssize_t smk_write_netlbladdr(struct file *file, const char __user *buf,
				size_t count, loff_t *ppos)
{
	struct smk_netlbladdr *skp;
	struct sockaddr_in newname;
	char smack[SMK_LABELLEN];
	char *sp;
	char data[SMK_NETLBLADDRMAX];
	char *host = (char *)&newname.sin_addr.s_addr;
	int rc;
	struct netlbl_audit audit_info;
	struct in_addr mask;
	unsigned int m;
784
	int found;
785
	u32 mask_bits = (1<<31);
786
	__be32 nsa;
787
	u32 temp_mask;
788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818

	/*
	 * Must have privilege.
	 * No partial writes.
	 * Enough data must be present.
	 * "<addr/mask, as a.b.c.d/e><space><label>"
	 * "<addr, as a.b.c.d><space><label>"
	 */
	if (!capable(CAP_MAC_ADMIN))
		return -EPERM;
	if (*ppos != 0)
		return -EINVAL;
	if (count < SMK_NETLBLADDRMIN || count > SMK_NETLBLADDRMAX)
		return -EINVAL;
	if (copy_from_user(data, buf, count) != 0)
		return -EFAULT;

	data[count] = '\0';

	rc = sscanf(data, "%hhd.%hhd.%hhd.%hhd/%d %s",
		&host[0], &host[1], &host[2], &host[3], &m, smack);
	if (rc != 6) {
		rc = sscanf(data, "%hhd.%hhd.%hhd.%hhd %s",
			&host[0], &host[1], &host[2], &host[3], smack);
		if (rc != 5)
			return -EINVAL;
		m = BEBITS;
	}
	if (m > BEBITS)
		return -EINVAL;

819 820 821 822 823 824 825 826 827 828 829 830
	/* if smack begins with '-', its an option, don't import it */
	if (smack[0] != '-') {
		sp = smk_import(smack, 0);
		if (sp == NULL)
			return -EINVAL;
	} else {
		/* check known options */
		if (strcmp(smack, smack_cipso_option) == 0)
			sp = (char *)smack_cipso_option;
		else
			return -EINVAL;
	}
831

832 833 834
	for (temp_mask = 0; m > 0; m--) {
		temp_mask |= mask_bits;
		mask_bits >>= 1;
835
	}
836 837 838
	mask.s_addr = cpu_to_be32(temp_mask);

	newname.sin_addr.s_addr &= mask.s_addr;
839 840 841 842 843 844 845
	/*
	 * Only allow one writer at a time. Writes should be
	 * quite rare and small in any case.
	 */
	mutex_lock(&smk_netlbladdr_lock);

	nsa = newname.sin_addr.s_addr;
846
	/* try to find if the prefix is already in the list */
847 848
	found = 0;
	list_for_each_entry_rcu(skp, &smk_netlbladdr_list, list) {
849
		if (skp->smk_host.sin_addr.s_addr == nsa &&
850 851
		    skp->smk_mask.s_addr == mask.s_addr) {
			found = 1;
852
			break;
853 854
		}
	}
855 856
	smk_netlabel_audit_set(&audit_info);

857
	if (found == 0) {
858 859 860 861 862 863 864 865
		skp = kzalloc(sizeof(*skp), GFP_KERNEL);
		if (skp == NULL)
			rc = -ENOMEM;
		else {
			rc = 0;
			skp->smk_host.sin_addr.s_addr = newname.sin_addr.s_addr;
			skp->smk_mask.s_addr = mask.s_addr;
			skp->smk_label = sp;
866
			smk_netlbladdr_insert(skp);
867 868
		}
	} else {
869 870 871 872 873 874 875 876
		/* we delete the unlabeled entry, only if the previous label
		 * wasnt the special CIPSO option */
		if (skp->smk_label != smack_cipso_option)
			rc = netlbl_cfg_unlbl_static_del(&init_net, NULL,
					&skp->smk_host.sin_addr, &skp->smk_mask,
					PF_INET, &audit_info);
		else
			rc = 0;
877 878 879 880 881 882
		skp->smk_label = sp;
	}

	/*
	 * Now tell netlabel about the single label nature of
	 * this host so that incoming packets get labeled.
883
	 * but only if we didn't get the special CIPSO option
884
	 */
885
	if (rc == 0 && sp != smack_cipso_option)
886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905
		rc = netlbl_cfg_unlbl_static_add(&init_net, NULL,
			&skp->smk_host.sin_addr, &skp->smk_mask, PF_INET,
			smack_to_secid(skp->smk_label), &audit_info);

	if (rc == 0)
		rc = count;

	mutex_unlock(&smk_netlbladdr_lock);

	return rc;
}

static const struct file_operations smk_netlbladdr_ops = {
	.open           = smk_open_netlbladdr,
	.read		= seq_read,
	.llseek         = seq_lseek,
	.write		= smk_write_netlbladdr,
	.release        = seq_release,
};

906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931
/**
 * smk_read_doi - read() for /smack/doi
 * @filp: file pointer, not actually used
 * @buf: where to put the result
 * @count: maximum to send along
 * @ppos: where to start
 *
 * Returns number of bytes read or error code, as appropriate
 */
static ssize_t smk_read_doi(struct file *filp, char __user *buf,
			    size_t count, loff_t *ppos)
{
	char temp[80];
	ssize_t rc;

	if (*ppos != 0)
		return 0;

	sprintf(temp, "%d", smk_cipso_doi_value);
	rc = simple_read_from_buffer(buf, count, ppos, temp, strlen(temp));

	return rc;
}

/**
 * smk_write_doi - write() for /smack/doi
932
 * @file: file pointer, not actually used
933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996
 * @buf: where to get the data from
 * @count: bytes sent
 * @ppos: where to start
 *
 * Returns number of bytes written or error code, as appropriate
 */
static ssize_t smk_write_doi(struct file *file, const char __user *buf,
			     size_t count, loff_t *ppos)
{
	char temp[80];
	int i;

	if (!capable(CAP_MAC_ADMIN))
		return -EPERM;

	if (count >= sizeof(temp) || count == 0)
		return -EINVAL;

	if (copy_from_user(temp, buf, count) != 0)
		return -EFAULT;

	temp[count] = '\0';

	if (sscanf(temp, "%d", &i) != 1)
		return -EINVAL;

	smk_cipso_doi_value = i;

	smk_cipso_doi();

	return count;
}

static const struct file_operations smk_doi_ops = {
	.read		= smk_read_doi,
	.write		= smk_write_doi,
};

/**
 * smk_read_direct - read() for /smack/direct
 * @filp: file pointer, not actually used
 * @buf: where to put the result
 * @count: maximum to send along
 * @ppos: where to start
 *
 * Returns number of bytes read or error code, as appropriate
 */
static ssize_t smk_read_direct(struct file *filp, char __user *buf,
			       size_t count, loff_t *ppos)
{
	char temp[80];
	ssize_t rc;

	if (*ppos != 0)
		return 0;

	sprintf(temp, "%d", smack_cipso_direct);
	rc = simple_read_from_buffer(buf, count, ppos, temp, strlen(temp));

	return rc;
}

/**
 * smk_write_direct - write() for /smack/direct
997
 * @file: file pointer, not actually used
998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054
 * @buf: where to get the data from
 * @count: bytes sent
 * @ppos: where to start
 *
 * Returns number of bytes written or error code, as appropriate
 */
static ssize_t smk_write_direct(struct file *file, const char __user *buf,
				size_t count, loff_t *ppos)
{
	char temp[80];
	int i;

	if (!capable(CAP_MAC_ADMIN))
		return -EPERM;

	if (count >= sizeof(temp) || count == 0)
		return -EINVAL;

	if (copy_from_user(temp, buf, count) != 0)
		return -EFAULT;

	temp[count] = '\0';

	if (sscanf(temp, "%d", &i) != 1)
		return -EINVAL;

	smack_cipso_direct = i;

	return count;
}

static const struct file_operations smk_direct_ops = {
	.read		= smk_read_direct,
	.write		= smk_write_direct,
};

/**
 * smk_read_ambient - read() for /smack/ambient
 * @filp: file pointer, not actually used
 * @buf: where to put the result
 * @cn: maximum to send along
 * @ppos: where to start
 *
 * Returns number of bytes read or error code, as appropriate
 */
static ssize_t smk_read_ambient(struct file *filp, char __user *buf,
				size_t cn, loff_t *ppos)
{
	ssize_t rc;
	int asize;

	if (*ppos != 0)
		return 0;
	/*
	 * Being careful to avoid a problem in the case where
	 * smack_net_ambient gets changed in midstream.
	 */
1055
	mutex_lock(&smack_ambient_lock);
1056

1057 1058 1059 1060 1061 1062 1063
	asize = strlen(smack_net_ambient) + 1;

	if (cn >= asize)
		rc = simple_read_from_buffer(buf, cn, ppos,
					     smack_net_ambient, asize);
	else
		rc = -EINVAL;
1064

1065
	mutex_unlock(&smack_ambient_lock);
1066 1067 1068 1069 1070 1071

	return rc;
}

/**
 * smk_write_ambient - write() for /smack/ambient
1072
 * @file: file pointer, not actually used
1073 1074 1075 1076 1077 1078 1079 1080 1081 1082
 * @buf: where to get the data from
 * @count: bytes sent
 * @ppos: where to start
 *
 * Returns number of bytes written or error code, as appropriate
 */
static ssize_t smk_write_ambient(struct file *file, const char __user *buf,
				 size_t count, loff_t *ppos)
{
	char in[SMK_LABELLEN];
1083
	char *oldambient;
1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098
	char *smack;

	if (!capable(CAP_MAC_ADMIN))
		return -EPERM;

	if (count >= SMK_LABELLEN)
		return -EINVAL;

	if (copy_from_user(in, buf, count) != 0)
		return -EFAULT;

	smack = smk_import(in, count);
	if (smack == NULL)
		return -EINVAL;

1099 1100 1101
	mutex_lock(&smack_ambient_lock);

	oldambient = smack_net_ambient;
1102
	smack_net_ambient = smack;
1103 1104 1105
	smk_unlbl_ambient(oldambient);

	mutex_unlock(&smack_ambient_lock);
1106 1107 1108 1109 1110 1111 1112 1113 1114

	return count;
}

static const struct file_operations smk_ambient_ops = {
	.read		= smk_read_ambient,
	.write		= smk_write_ambient,
};

1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146
/**
 * smk_read_onlycap - read() for /smack/onlycap
 * @filp: file pointer, not actually used
 * @buf: where to put the result
 * @cn: maximum to send along
 * @ppos: where to start
 *
 * Returns number of bytes read or error code, as appropriate
 */
static ssize_t smk_read_onlycap(struct file *filp, char __user *buf,
				size_t cn, loff_t *ppos)
{
	char *smack = "";
	ssize_t rc = -EINVAL;
	int asize;

	if (*ppos != 0)
		return 0;

	if (smack_onlycap != NULL)
		smack = smack_onlycap;

	asize = strlen(smack) + 1;

	if (cn >= asize)
		rc = simple_read_from_buffer(buf, cn, ppos, smack, asize);

	return rc;
}

/**
 * smk_write_onlycap - write() for /smack/onlycap
1147
 * @file: file pointer, not actually used
1148 1149 1150 1151 1152 1153 1154 1155 1156 1157
 * @buf: where to get the data from
 * @count: bytes sent
 * @ppos: where to start
 *
 * Returns number of bytes written or error code, as appropriate
 */
static ssize_t smk_write_onlycap(struct file *file, const char __user *buf,
				 size_t count, loff_t *ppos)
{
	char in[SMK_LABELLEN];
1158
	char *sp = current->cred->security;
1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193

	if (!capable(CAP_MAC_ADMIN))
		return -EPERM;

	/*
	 * This can be done using smk_access() but is done
	 * explicitly for clarity. The smk_access() implementation
	 * would use smk_access(smack_onlycap, MAY_WRITE)
	 */
	if (smack_onlycap != NULL && smack_onlycap != sp)
		return -EPERM;

	if (count >= SMK_LABELLEN)
		return -EINVAL;

	if (copy_from_user(in, buf, count) != 0)
		return -EFAULT;

	/*
	 * Should the null string be passed in unset the onlycap value.
	 * This seems like something to be careful with as usually
	 * smk_import only expects to return NULL for errors. It
	 * is usually the case that a nullstring or "\n" would be
	 * bad to pass to smk_import but in fact this is useful here.
	 */
	smack_onlycap = smk_import(in, count);

	return count;
}

static const struct file_operations smk_onlycap_ops = {
	.read		= smk_read_onlycap,
	.write		= smk_write_onlycap,
};

1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219
/**
 * smk_fill_super - fill the /smackfs superblock
 * @sb: the empty superblock
 * @data: unused
 * @silent: unused
 *
 * Fill in the well known entries for /smack
 *
 * Returns 0 on success, an error code on failure
 */
static int smk_fill_super(struct super_block *sb, void *data, int silent)
{
	int rc;
	struct inode *root_inode;

	static struct tree_descr smack_files[] = {
		[SMK_LOAD]	=
			{"load", &smk_load_ops, S_IRUGO|S_IWUSR},
		[SMK_CIPSO]	=
			{"cipso", &smk_cipso_ops, S_IRUGO|S_IWUSR},
		[SMK_DOI]	=
			{"doi", &smk_doi_ops, S_IRUGO|S_IWUSR},
		[SMK_DIRECT]	=
			{"direct", &smk_direct_ops, S_IRUGO|S_IWUSR},
		[SMK_AMBIENT]	=
			{"ambient", &smk_ambient_ops, S_IRUGO|S_IWUSR},
1220 1221
		[SMK_NETLBLADDR] =
			{"netlabel", &smk_netlbladdr_ops, S_IRUGO|S_IWUSR},
1222 1223
		[SMK_ONLYCAP]	=
			{"onlycap", &smk_onlycap_ops, S_IRUGO|S_IWUSR},
1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271
		/* last one */ {""}
	};

	rc = simple_fill_super(sb, SMACK_MAGIC, smack_files);
	if (rc != 0) {
		printk(KERN_ERR "%s failed %d while creating inodes\n",
			__func__, rc);
		return rc;
	}

	root_inode = sb->s_root->d_inode;
	root_inode->i_security = new_inode_smack(smack_known_floor.smk_known);

	return 0;
}

/**
 * smk_get_sb - get the smackfs superblock
 * @fs_type: passed along without comment
 * @flags: passed along without comment
 * @dev_name: passed along without comment
 * @data: passed along without comment
 * @mnt: passed along without comment
 *
 * Just passes everything along.
 *
 * Returns what the lower level code does.
 */
static int smk_get_sb(struct file_system_type *fs_type,
		      int flags, const char *dev_name, void *data,
		      struct vfsmount *mnt)
{
	return get_sb_single(fs_type, flags, data, smk_fill_super, mnt);
}

static struct file_system_type smk_fs_type = {
	.name		= "smackfs",
	.get_sb		= smk_get_sb,
	.kill_sb	= kill_litter_super,
};

static struct vfsmount *smackfs_mount;

/**
 * init_smk_fs - get the smackfs superblock
 *
 * register the smackfs
 *
1272 1273 1274 1275 1276 1277 1278
 * Do not register smackfs if Smack wasn't enabled
 * on boot. We can not put this method normally under the
 * smack_init() code path since the security subsystem get
 * initialized before the vfs caches.
 *
 * Returns true if we were not chosen on boot or if
 * we were chosen and filesystem registration succeeded.
1279 1280 1281 1282 1283
 */
static int __init init_smk_fs(void)
{
	int err;

1284 1285 1286
	if (!security_module_enable(&smack_ops))
		return 0;

1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297
	err = register_filesystem(&smk_fs_type);
	if (!err) {
		smackfs_mount = kern_mount(&smk_fs_type);
		if (IS_ERR(smackfs_mount)) {
			printk(KERN_ERR "smackfs:  could not mount!\n");
			err = PTR_ERR(smackfs_mount);
			smackfs_mount = NULL;
		}
	}

	smk_cipso_doi();
1298
	smk_unlbl_ambient(NULL);
1299 1300 1301 1302 1303

	return err;
}

__initcall(init_smk_fs);