cregit-Linux how code gets into the kernel

Release 4.7 security/selinux/netport.c

Directory: security/selinux
/*
 * Network port table
 *
 * SELinux must keep a mapping of network ports to labels/SIDs.  This
 * mapping is maintained as part of the normal policy but a fast cache is
 * needed to reduce the lookup overhead.
 *
 * Author: Paul Moore <paul@paul-moore.com>
 *
 * This code is heavily based on the "netif" concept originally developed by
 * James Morris <jmorris@redhat.com>
 *   (see security/selinux/netif.c for more information)
 *
 */

/*
 * (c) Copyright Hewlett-Packard Development Company, L.P., 2008
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * 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.
 *
 */

#include <linux/types.h>
#include <linux/rcupdate.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/in.h>
#include <linux/in6.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <net/ip.h>
#include <net/ipv6.h>

#include "netport.h"
#include "objsec.h"


#define SEL_NETPORT_HASH_SIZE       256

#define SEL_NETPORT_HASH_BKT_LIMIT   16


struct sel_netport_bkt {
	
int size;
	
struct list_head list;
};


struct sel_netport {
	
struct netport_security_struct psec;

	
struct list_head list;
	
struct rcu_head rcu;
};

/* NOTE: we are using a combined hash table for both IPv4 and IPv6, the reason
 * for this is that I suspect most users will not make heavy use of both
 * address families at the same time so one table will usually end up wasted,
 * if this becomes a problem we can always add a hash table for each address
 * family later */

static LIST_HEAD(sel_netport_list);
static DEFINE_SPINLOCK(sel_netport_lock);

static struct sel_netport_bkt sel_netport_hash[SEL_NETPORT_HASH_SIZE];

/**
 * sel_netport_hashfn - Hashing function for the port table
 * @pnum: port number
 *
 * Description:
 * This is the hashing function for the port table, it returns the bucket
 * number for the given port.
 *
 */

static unsigned int sel_netport_hashfn(u16 pnum) { return (pnum & (SEL_NETPORT_HASH_SIZE - 1)); }

Contributors

PersonTokensPropCommitsCommitProp
james morrisjames morris21100.00%1100.00%
Total21100.00%1100.00%

/** * sel_netport_find - Search for a port record * @protocol: protocol * @port: pnum * * Description: * Search the network port table and return the matching record. If an entry * can not be found in the table return NULL. * */
static struct sel_netport *sel_netport_find(u8 protocol, u16 pnum) { unsigned int idx; struct sel_netport *port; idx = sel_netport_hashfn(pnum); list_for_each_entry_rcu(port, &sel_netport_hash[idx].list, list) if (port->psec.port == pnum && port->psec.protocol == protocol) return port; return NULL; }

Contributors

PersonTokensPropCommitsCommitProp
james morrisjames morris62100.00%1100.00%
Total62100.00%1100.00%

/** * sel_netport_insert - Insert a new port into the table * @port: the new port record * * Description: * Add a new port record to the network address hash table. * */
static void sel_netport_insert(struct sel_netport *port) { unsigned int idx; /* we need to impose a limit on the growth of the hash table so check * this bucket to make sure it is within the specified bounds */ idx = sel_netport_hashfn(port->psec.port); list_add_rcu(&port->list, &sel_netport_hash[idx].list); if (sel_netport_hash[idx].size == SEL_NETPORT_HASH_BKT_LIMIT) { struct sel_netport *tail; tail = list_entry( rcu_dereference_protected( sel_netport_hash[idx].list.prev, lockdep_is_held(&sel_netport_lock)), struct sel_netport, list); list_del_rcu(&tail->list); kfree_rcu(tail, rcu); } else sel_netport_hash[idx].size++; }

Contributors

PersonTokensPropCommitsCommitProp
james morrisjames morris9483.19%125.00%
paul moorepaul moore108.85%125.00%
david howellsdavid howells76.19%125.00%
lai jiangshanlai jiangshan21.77%125.00%
Total113100.00%4100.00%

/** * sel_netport_sid_slow - Lookup the SID of a network address using the policy * @protocol: protocol * @pnum: port * @sid: port SID * * Description: * This function determines the SID of a network port by quering the security * policy. The result is added to the network port table to speedup future * queries. Returns zero on success, negative values on failure. * */
static int sel_netport_sid_slow(u8 protocol, u16 pnum, u32 *sid) { int ret = -ENOMEM; struct sel_netport *port; struct sel_netport *new = NULL; spin_lock_bh(&sel_netport_lock); port = sel_netport_find(protocol, pnum); if (port != NULL) { *sid = port->psec.sid; spin_unlock_bh(&sel_netport_lock); return 0; } new = kzalloc(sizeof(*new), GFP_ATOMIC); if (new == NULL) goto out; ret = security_port_sid(protocol, pnum, sid); if (ret != 0) goto out; new->psec.port = pnum; new->psec.protocol = protocol; new->psec.sid = *sid; sel_netport_insert(new); out: spin_unlock_bh(&sel_netport_lock); if (unlikely(ret)) { printk(KERN_WARNING "SELinux: failure in sel_netport_sid_slow()," " unable to determine network port label\n"); kfree(new); } return ret; }

Contributors

PersonTokensPropCommitsCommitProp
james morrisjames morris16089.39%150.00%
paul moorepaul moore1910.61%150.00%
Total179100.00%2100.00%

/** * sel_netport_sid - Lookup the SID of a network port * @protocol: protocol * @pnum: port * @sid: port SID * * Description: * This function determines the SID of a network port using the fastest method * possible. First the port table is queried, but if an entry can't be found * then the policy is queried and the result is added to the table to speedup * future queries. Returns zero on success, negative values on failure. * */
int sel_netport_sid(u8 protocol, u16 pnum, u32 *sid) { struct sel_netport *port; rcu_read_lock(); port = sel_netport_find(protocol, pnum); if (port != NULL) { *sid = port->psec.sid; rcu_read_unlock(); return 0; } rcu_read_unlock(); return sel_netport_sid_slow(protocol, pnum, sid); }

Contributors

PersonTokensPropCommitsCommitProp
james morrisjames morris68100.00%1100.00%
Total68100.00%1100.00%

/** * sel_netport_flush - Flush the entire network port table * * Description: * Remove all entries from the network address table. * */
void sel_netport_flush(void) { unsigned int idx; struct sel_netport *port, *port_tmp; spin_lock_bh(&sel_netport_lock); for (idx = 0; idx < SEL_NETPORT_HASH_SIZE; idx++) { list_for_each_entry_safe(port, port_tmp, &sel_netport_hash[idx].list, list) { list_del_rcu(&port->list); kfree_rcu(port, rcu); } sel_netport_hash[idx].size = 0; } spin_unlock_bh(&sel_netport_lock); }

Contributors

PersonTokensPropCommitsCommitProp
james morrisjames morris7490.24%133.33%
paul moorepaul moore67.32%133.33%
lai jiangshanlai jiangshan22.44%133.33%
Total82100.00%3100.00%


static __init int sel_netport_init(void) { int iter; if (!selinux_enabled) return 0; for (iter = 0; iter < SEL_NETPORT_HASH_SIZE; iter++) { INIT_LIST_HEAD(&sel_netport_hash[iter].list); sel_netport_hash[iter].size = 0; } return 0; }

Contributors

PersonTokensPropCommitsCommitProp
james morrisjames morris5798.28%150.00%
paul moorepaul moore11.72%150.00%
Total58100.00%2100.00%

__initcall(sel_netport_init);

Overall Contributors

PersonTokensPropCommitsCommitProp
james morrisjames morris64192.50%114.29%
paul moorepaul moore385.48%342.86%
david howellsdavid howells71.01%114.29%
lai jiangshanlai jiangshan40.58%114.29%
tejun heotejun heo30.43%114.29%
Total693100.00%7100.00%
Directory: security/selinux
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