~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/security/selinux/netport.c

Version: ~ [ linux-5.12-rc1 ] ~ [ linux-5.11.2 ] ~ [ linux-5.10.19 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.101 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.177 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.222 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.258 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.258 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.18.140 ] ~ [ linux-3.16.85 ] ~ [ linux-3.14.79 ] ~ [ linux-3.12.74 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  * Network port table
  3  *
  4  * SELinux must keep a mapping of network ports to labels/SIDs.  This
  5  * mapping is maintained as part of the normal policy but a fast cache is
  6  * needed to reduce the lookup overhead.
  7  *
  8  * Author: Paul Moore <paul.moore@hp.com>
  9  *
 10  * This code is heavily based on the "netif" concept originally developed by
 11  * James Morris <jmorris@redhat.com>
 12  *   (see security/selinux/netif.c for more information)
 13  *
 14  */
 15 
 16 /*
 17  * (c) Copyright Hewlett-Packard Development Company, L.P., 2008
 18  *
 19  * This program is free software: you can redistribute it and/or modify
 20  * it under the terms of version 2 of the GNU General Public License as
 21  * published by the Free Software Foundation.
 22  *
 23  * This program is distributed in the hope that it will be useful,
 24  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 25  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 26  * GNU General Public License for more details.
 27  *
 28  */
 29 
 30 #include <linux/types.h>
 31 #include <linux/rcupdate.h>
 32 #include <linux/list.h>
 33 #include <linux/spinlock.h>
 34 #include <linux/in.h>
 35 #include <linux/in6.h>
 36 #include <linux/ip.h>
 37 #include <linux/ipv6.h>
 38 #include <net/ip.h>
 39 #include <net/ipv6.h>
 40 
 41 #include "netport.h"
 42 #include "objsec.h"
 43 
 44 #define SEL_NETPORT_HASH_SIZE       256
 45 #define SEL_NETPORT_HASH_BKT_LIMIT   16
 46 
 47 struct sel_netport_bkt {
 48         int size;
 49         struct list_head list;
 50 };
 51 
 52 struct sel_netport {
 53         struct netport_security_struct psec;
 54 
 55         struct list_head list;
 56         struct rcu_head rcu;
 57 };
 58 
 59 /* NOTE: we are using a combined hash table for both IPv4 and IPv6, the reason
 60  * for this is that I suspect most users will not make heavy use of both
 61  * address families at the same time so one table will usually end up wasted,
 62  * if this becomes a problem we can always add a hash table for each address
 63  * family later */
 64 
 65 static LIST_HEAD(sel_netport_list);
 66 static DEFINE_SPINLOCK(sel_netport_lock);
 67 static struct sel_netport_bkt sel_netport_hash[SEL_NETPORT_HASH_SIZE];
 68 
 69 /**
 70  * sel_netport_free - Frees a port entry
 71  * @p: the entry's RCU field
 72  *
 73  * Description:
 74  * This function is designed to be used as a callback to the call_rcu()
 75  * function so that memory allocated to a hash table port entry can be
 76  * released safely.
 77  *
 78  */
 79 static void sel_netport_free(struct rcu_head *p)
 80 {
 81         struct sel_netport *port = container_of(p, struct sel_netport, rcu);
 82         kfree(port);
 83 }
 84 
 85 /**
 86  * sel_netport_hashfn - Hashing function for the port table
 87  * @pnum: port number
 88  *
 89  * Description:
 90  * This is the hashing function for the port table, it returns the bucket
 91  * number for the given port.
 92  *
 93  */
 94 static unsigned int sel_netport_hashfn(u16 pnum)
 95 {
 96         return (pnum & (SEL_NETPORT_HASH_SIZE - 1));
 97 }
 98 
 99 /**
100  * sel_netport_find - Search for a port record
101  * @protocol: protocol
102  * @port: pnum
103  *
104  * Description:
105  * Search the network port table and return the matching record.  If an entry
106  * can not be found in the table return NULL.
107  *
108  */
109 static struct sel_netport *sel_netport_find(u8 protocol, u16 pnum)
110 {
111         unsigned int idx;
112         struct sel_netport *port;
113 
114         idx = sel_netport_hashfn(pnum);
115         list_for_each_entry_rcu(port, &sel_netport_hash[idx].list, list)
116                 if (port->psec.port == pnum && port->psec.protocol == protocol)
117                         return port;
118 
119         return NULL;
120 }
121 
122 /**
123  * sel_netport_insert - Insert a new port into the table
124  * @port: the new port record
125  *
126  * Description:
127  * Add a new port record to the network address hash table.
128  *
129  */
130 static void sel_netport_insert(struct sel_netport *port)
131 {
132         unsigned int idx;
133 
134         /* we need to impose a limit on the growth of the hash table so check
135          * this bucket to make sure it is within the specified bounds */
136         idx = sel_netport_hashfn(port->psec.port);
137         list_add_rcu(&port->list, &sel_netport_hash[idx].list);
138         if (sel_netport_hash[idx].size == SEL_NETPORT_HASH_BKT_LIMIT) {
139                 struct sel_netport *tail;
140                 tail = list_entry(
141                         rcu_dereference(sel_netport_hash[idx].list.prev),
142                         struct sel_netport, list);
143                 list_del_rcu(&tail->list);
144                 call_rcu(&tail->rcu, sel_netport_free);
145         } else
146                 sel_netport_hash[idx].size++;
147 }
148 
149 /**
150  * sel_netport_sid_slow - Lookup the SID of a network address using the policy
151  * @protocol: protocol
152  * @pnum: port
153  * @sid: port SID
154  *
155  * Description:
156  * This function determines the SID of a network port by quering the security
157  * policy.  The result is added to the network port table to speedup future
158  * queries.  Returns zero on success, negative values on failure.
159  *
160  */
161 static int sel_netport_sid_slow(u8 protocol, u16 pnum, u32 *sid)
162 {
163         int ret = -ENOMEM;
164         struct sel_netport *port;
165         struct sel_netport *new = NULL;
166 
167         spin_lock_bh(&sel_netport_lock);
168         port = sel_netport_find(protocol, pnum);
169         if (port != NULL) {
170                 *sid = port->psec.sid;
171                 spin_unlock_bh(&sel_netport_lock);
172                 return 0;
173         }
174         new = kzalloc(sizeof(*new), GFP_ATOMIC);
175         if (new == NULL)
176                 goto out;
177         ret = security_port_sid(protocol, pnum, sid);
178         if (ret != 0)
179                 goto out;
180 
181         new->psec.port = pnum;
182         new->psec.protocol = protocol;
183         new->psec.sid = *sid;
184         sel_netport_insert(new);
185 
186 out:
187         spin_unlock_bh(&sel_netport_lock);
188         if (unlikely(ret)) {
189                 printk(KERN_WARNING
190                        "SELinux: failure in sel_netport_sid_slow(),"
191                        " unable to determine network port label\n");
192                 kfree(new);
193         }
194         return ret;
195 }
196 
197 /**
198  * sel_netport_sid - Lookup the SID of a network port
199  * @protocol: protocol
200  * @pnum: port
201  * @sid: port SID
202  *
203  * Description:
204  * This function determines the SID of a network port using the fastest method
205  * possible.  First the port table is queried, but if an entry can't be found
206  * then the policy is queried and the result is added to the table to speedup
207  * future queries.  Returns zero on success, negative values on failure.
208  *
209  */
210 int sel_netport_sid(u8 protocol, u16 pnum, u32 *sid)
211 {
212         struct sel_netport *port;
213 
214         rcu_read_lock();
215         port = sel_netport_find(protocol, pnum);
216         if (port != NULL) {
217                 *sid = port->psec.sid;
218                 rcu_read_unlock();
219                 return 0;
220         }
221         rcu_read_unlock();
222 
223         return sel_netport_sid_slow(protocol, pnum, sid);
224 }
225 
226 /**
227  * sel_netport_flush - Flush the entire network port table
228  *
229  * Description:
230  * Remove all entries from the network address table.
231  *
232  */
233 static void sel_netport_flush(void)
234 {
235         unsigned int idx;
236         struct sel_netport *port, *port_tmp;
237 
238         spin_lock_bh(&sel_netport_lock);
239         for (idx = 0; idx < SEL_NETPORT_HASH_SIZE; idx++) {
240                 list_for_each_entry_safe(port, port_tmp,
241                                          &sel_netport_hash[idx].list, list) {
242                         list_del_rcu(&port->list);
243                         call_rcu(&port->rcu, sel_netport_free);
244                 }
245                 sel_netport_hash[idx].size = 0;
246         }
247         spin_unlock_bh(&sel_netport_lock);
248 }
249 
250 static int sel_netport_avc_callback(u32 event, u32 ssid, u32 tsid,
251                                     u16 class, u32 perms, u32 *retained)
252 {
253         if (event == AVC_CALLBACK_RESET) {
254                 sel_netport_flush();
255                 synchronize_net();
256         }
257         return 0;
258 }
259 
260 static __init int sel_netport_init(void)
261 {
262         int iter;
263         int ret;
264 
265         if (!selinux_enabled)
266                 return 0;
267 
268         for (iter = 0; iter < SEL_NETPORT_HASH_SIZE; iter++) {
269                 INIT_LIST_HEAD(&sel_netport_hash[iter].list);
270                 sel_netport_hash[iter].size = 0;
271         }
272 
273         ret = avc_add_callback(sel_netport_avc_callback, AVC_CALLBACK_RESET,
274                                SECSID_NULL, SECSID_NULL, SECCLASS_NULL, 0);
275         if (ret != 0)
276                 panic("avc_add_callback() failed, error %d\n", ret);
277 
278         return ret;
279 }
280 
281 __initcall(sel_netport_init);
282 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp