diff options
Diffstat (limited to 'security')
| -rw-r--r-- | security/selinux/include/netport.h | 31 | ||||
| -rw-r--r-- | security/selinux/netport.c | 286 |
2 files changed, 317 insertions, 0 deletions
diff --git a/security/selinux/include/netport.h b/security/selinux/include/netport.h new file mode 100644 index 000000000000..8991752eaf93 --- /dev/null +++ b/security/selinux/include/netport.h @@ -0,0 +1,31 @@ +/* + * 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.moore@hp.com> + * + */ + +/* + * (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. + * + */ + +#ifndef _SELINUX_NETPORT_H +#define _SELINUX_NETPORT_H + +int sel_netport_sid(u8 protocol, u16 pnum, u32 *sid); + +#endif diff --git a/security/selinux/netport.c b/security/selinux/netport.c new file mode 100644 index 000000000000..68ede3c498ab --- /dev/null +++ b/security/selinux/netport.c @@ -0,0 +1,286 @@ +/* + * 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.moore@hp.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/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 <asm/bug.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_free - Frees a port entry + * @p: the entry's RCU field + * + * Description: + * This function is designed to be used as a callback to the call_rcu() + * function so that memory allocated to a hash table port entry can be + * released safely. + * + */ +static void sel_netport_free(struct rcu_head *p) +{ + struct sel_netport *port = container_of(p, struct sel_netport, rcu); + kfree(port); +} + +/** + * 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)); +} + +/** + * 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; +} + +/** + * 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. Returns zero on + * success, negative values on failure. + * + */ +static int 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(port->list.prev, struct sel_netport, list); + list_del_rcu(port->list.prev); + call_rcu(&tail->rcu, sel_netport_free); + } else + sel_netport_hash[idx].size++; + + return 0; +} + +/** + * 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; + 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; + ret = 0; + goto out; + } + new = kzalloc(sizeof(*new), GFP_ATOMIC); + if (new == NULL) { + ret = -ENOMEM; + goto out; + } + ret = security_port_sid(protocol, pnum, &new->psec.sid); + if (ret != 0) + goto out; + new->psec.port = pnum; + new->psec.protocol = protocol; + ret = sel_netport_insert(new); + if (ret != 0) + goto out; + *sid = new->psec.sid; + +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; +} + +/** + * 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); +} + +/** + * sel_netport_flush - Flush the entire network port table + * + * Description: + * Remove all entries from the network address table. + * + */ +static void sel_netport_flush(void) +{ + unsigned int idx; + struct sel_netport *port; + + spin_lock_bh(&sel_netport_lock); + for (idx = 0; idx < SEL_NETPORT_HASH_SIZE; idx++) { + list_for_each_entry(port, &sel_netport_hash[idx].list, list) { + list_del_rcu(&port->list); + call_rcu(&port->rcu, sel_netport_free); + } + sel_netport_hash[idx].size = 0; + } + spin_unlock_bh(&sel_netport_lock); +} + +static int sel_netport_avc_callback(u32 event, u32 ssid, u32 tsid, + u16 class, u32 perms, u32 *retained) +{ + if (event == AVC_CALLBACK_RESET) { + sel_netport_flush(); + synchronize_net(); + } + return 0; +} + +static __init int sel_netport_init(void) +{ + int iter; + int ret; + + 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; + } + + ret = avc_add_callback(sel_netport_avc_callback, AVC_CALLBACK_RESET, + SECSID_NULL, SECSID_NULL, SECCLASS_NULL, 0); + if (ret != 0) + panic("avc_add_callback() failed, error %d\n", ret); + + return ret; +} + +__initcall(sel_netport_init); |