/*
* CALIPSO - Common Architecture Label IPv6 Security Option
*
* This is an implementation of the CALIPSO protocol as specified in
* RFC 5570.
*
* Authors: Paul Moore <paul.moore@hp.com>
* Huw Davies <huw@codeweavers.com>
*
*/
/* (c) Copyright Hewlett-Packard Development Company, L.P., 2006, 2008
* (c) Copyright Huw Davies <huw@codeweavers.com>, 2015
*
* 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; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
* the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*
*/
#include <linux/init.h>
#include <linux/types.h>
#include <linux/rcupdate.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/jhash.h>
#include <linux/audit.h>
#include <linux/slab.h>
#include <net/ip.h>
#include <net/icmp.h>
#include <net/tcp.h>
#include <net/netlabel.h>
#include <net/calipso.h>
#include <linux/atomic.h>
#include <linux/bug.h>
#include <asm/unaligned.h>
/* List of available DOI definitions */
static DEFINE_SPINLOCK(calipso_doi_list_lock);
static LIST_HEAD(calipso_doi_list);
/* DOI List Functions
*/
/**
* calipso_doi_search - Searches for a DOI definition
* @doi: the DOI to search for
*
* Description:
* Search the DOI definition list for a DOI definition with a DOI value that
* matches @doi. The caller is responsible for calling rcu_read_[un]lock().
* Returns a pointer to the DOI definition on success and NULL on failure.
*/
static struct calipso_doi *calipso_doi_search(u32 doi)
{
struct calipso_doi *iter;
list_for_each_entry_rcu(iter, &calipso_doi_list, list)
if (iter->doi == doi && atomic_read(&iter->refcount))
return iter;
return NULL;
}
/**
* calipso_doi_add - Add a new DOI to the CALIPSO protocol engine
* @doi_def: the DOI structure
* @audit_info: NetLabel audit information
*
* Description:
* The caller defines a new DOI for use by the CALIPSO engine and calls this
* function to add it to the list of acceptable domains. The caller must
* ensure that the mapping table specified in @doi_def->map meets all of the
* requirements of the mapping type (see calipso.h for details). Returns
* zero on success and non-zero on failure.
*
*/
static int calipso_doi_add(struct calipso_doi *doi_def,
struct netlbl_audit *audit_info)
{
int ret_val = -EINVAL;
u32 doi;
u32 doi_type;
struct audit_buffer *audit_buf;
doi = doi_def->doi;
doi_type = doi_def->type;
if (doi_def->doi == CALIPSO_DOI_UNKNOWN)
goto doi_add_return;
atomic_set(&doi_def->refcount, 1);
spin_lock(&calipso_doi_list_lock);
if (calipso_doi_search(doi_def->doi)) {
spin_unlock(&calipso_doi_list_lock);
ret_val = -EEXIST;
goto doi_add_return;
}
list_add_tail_rcu(&doi_def->list, &calipso_doi_list);
spin_unlock(&calipso_doi_list_lock);
ret_val = 0;
doi_add_return:
audit_buf = netlbl_audit_start(AUDIT_MAC_CALIPSO_ADD, audit_info);
if (audit_buf) {
const char *type_str;
switch (doi_type) {
case CALIPSO_MAP_PASS:
type_str = "pass";
break;
default:
type_str = "(unknown)";
}
audit_log_format(audit_buf,
" calipso_doi=%u calipso_type=%s res=%u",
doi, type_str, ret_val == 0 ? 1 : 0);
audit_log_end(audit_buf);
}
return ret_val;
}
/**
* calipso_doi_free - Frees a DOI definition
* @doi_def: the DOI definition
*
* Description:
* This function frees all of the memory associated with a DOI definition.
*
*/
static void calipso_doi_free(struct calipso_doi *doi_def)
{
kfree(doi_def);
}
/**
* calipso_doi_free_rcu - Frees a DOI definition via the RCU pointer
* @entry: the entry's RCU field
*
* Description:
* This function is designed to be used as a callback to the call_rcu()
* function so that the memory allocated to the DOI definition can be released
* safely.
*
*/
static void calipso_doi_free_rcu(struct rcu_head *entry)
{
struct calipso_doi *doi_def;
doi_def = container_of(entry, struct calipso_doi, rcu);
calipso_doi_free(doi_def);
}
/**
* calipso_doi_remove - Remove an existing DOI from the CALIPSO protocol engine
* @doi: the DOI value
* @audit_secid: the LSM secid to use in the audit message
*
* Description:
* Removes a DOI definition from the CALIPSO engine. The NetLabel routines will
* be called to release their own LSM domain mappings as well as our own
* domain list. Returns zero on success and negative values on failure.
*
*/
static int calipso_doi_remove(u32 doi, struct netlbl_audit *audit_info)
{
int ret_val;
struct calipso_doi *doi_def;
struct audit_buffer *audit_buf;
spin_lock(&calipso_doi_list_lock);
doi_def = calipso_doi_search(doi);
if (!doi_def) {
spin_unlock(&calipso_doi_list_lock);
ret_val = -ENOENT;
goto doi_remove_return;
}
if (!atomic_dec_and_test(&doi_def->refcount)) {
spin_unlock(&calipso_doi_list_lock);
ret_val = -EBUSY;
goto doi_remove_return;
}
list_del_rcu(&doi_def->list);
spin_unlock(&calipso_doi_list_lock);
call_rcu(&doi_def->rcu, calipso_doi_free_rcu);
ret_val = 0;
doi_remove_return:
audit_buf = netlbl_audit_start(AUDIT_MAC_CALIPSO_DEL, audit_info);
if (audit_buf) {
audit_log_format(audit_buf,
" calipso_doi=%u res=%u",
doi, ret_val == 0 ? 1 : 0);
audit_log_end(audit_buf);
}
return ret_val;
}
/**
* calipso_doi_getdef - Returns a reference to a valid DOI definition
* @doi: the DOI value
*
* Description:
* Searches for a valid DOI definition and if one is found it is returned to
* the caller. Otherwise NULL is returned. The caller must ensure that
* calipso_doi_putdef() is called when the caller is done.
*
*/
static struct calipso_doi *calipso_doi_getdef(u32 doi)
{
struct calipso_doi *doi_def;
rcu_read_lock();
doi_def = calipso_doi_search(doi);
if (!doi_def)
goto doi_getdef_return;
if (!atomic_inc_not_zero(&doi_def->refcount))
doi_def = NULL;
doi_getdef_return:
rcu_read_unlock();
return doi_def;
}
/**
* calipso_doi_putdef - Releases a reference for the given DOI definition
* @doi_def: the DOI definition
*
* Description:
* Releases a DOI definition reference obtained from calipso_doi_getdef().
*
*/
static void calipso_doi_putdef(struct calipso_doi *doi_def)
{
if (!doi_def)
return;
if (!atomic_dec_and_test(&doi_def->refcount))
return;
spin_lock(&calipso_doi_list_lock);
list_del_rcu(&doi_def->list);
spin_unlock(&calipso_doi_list_lock);
call_rcu(&doi_def->rcu, calipso_doi_free_rcu);
}
/**
* calipso_doi_walk - Iterate through the DOI definitions
* @skip_cnt: skip past this number of DOI definitions, updated
* @callback: callback for each DOI definition
* @cb_arg: argument for the callback function
*
* Description:
* Iterate over the DOI definition list, skipping the first @skip_cnt entries.
* For each entry call @callback, if @callback returns a negative value stop
* 'walking' through the list and return. Updates the value in @skip_cnt upon
* return. Returns zero on success, negative values on failure.
*
*/
static int calipso_doi_walk(u32 *skip_cnt,
int (*callback)(struct calipso_doi *doi_def,
void *arg),
void *cb_arg)
{
int ret_val = -ENOENT;
u32 doi_cnt = 0;
struct calipso_doi *iter_doi;
rcu_read_lock();
list_for_each_entry_rcu(iter_doi, &calipso_doi_list, list)
if (atomic_read(&iter_doi->refcount) > 0) {
if (doi_cnt++ < *skip_cnt)
continue;
ret_val = callback(iter_doi, cb_arg);
if (ret_val < 0) {
doi_cnt--;
goto doi_walk_return;
}
}
doi_walk_return:
rcu_read_unlock();
*skip_cnt = doi_cnt;
return ret_val;
}
static const struct netlbl_calipso_ops ops = {
.doi_add = calipso_doi_add,
.doi_free = calipso_doi_free,
.doi_remove = calipso_doi_remove,
.doi_getdef = calipso_doi_getdef,
.doi_putdef = calipso_doi_putdef,
.doi_walk = calipso_doi_walk,
};
/**
* calipso_init - Initialize the CALIPSO module
*
* Description:
* Initialize the CALIPSO module and prepare it for use. Returns zero on
* success and negative values on failure.
*
*/
int __init calipso_init(void)
{
netlbl_calipso_ops_register(&ops);
return 0;
}
void calipso_exit(void)
{
netlbl_calipso_ops_register(NULL);
}
