1 /* 2 * SELinux NetLabel Support 3 * 4 * This file provides the necessary glue to tie NetLabel into the SELinux 5 * subsystem. 6 * 7 * Author: Paul Moore <paul.moore@hp.com> 8 * 9 */ 10 11 /* 12 * (c) Copyright Hewlett-Packard Development Company, L.P., 2007 13 * 14 * This program is free software; you can redistribute it and/or modify 15 * it under the terms of the GNU General Public License as published by 16 * the Free Software Foundation; either version 2 of the License, or 17 * (at your option) any later version. 18 * 19 * This program is distributed in the hope that it will be useful, 20 * but WITHOUT ANY WARRANTY; without even the implied warranty of 21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See 22 * the GNU General Public License for more details. 23 * 24 * You should have received a copy of the GNU General Public License 25 * along with this program; if not, write to the Free Software 26 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 27 * 28 */ 29 30 #include <linux/spinlock.h> 31 #include <linux/rcupdate.h> 32 #include <net/sock.h> 33 #include <net/netlabel.h> 34 35 #include "objsec.h" 36 #include "security.h" 37 38 /** 39 * selinux_netlbl_sock_setsid - Label a socket using the NetLabel mechanism 40 * @sk: the socket to label 41 * @sid: the SID to use 42 * 43 * Description: 44 * Attempt to label a socket using the NetLabel mechanism using the given 45 * SID. Returns zero values on success, negative values on failure. The 46 * caller is responsibile for calling rcu_read_lock() before calling this 47 * this function and rcu_read_unlock() after this function returns. 48 * 49 */ 50 static int selinux_netlbl_sock_setsid(struct sock *sk, u32 sid) 51 { 52 int rc; 53 struct sk_security_struct *sksec = sk->sk_security; 54 struct netlbl_lsm_secattr secattr; 55 56 rc = security_netlbl_sid_to_secattr(sid, &secattr); 57 if (rc != 0) 58 return rc; 59 60 rc = netlbl_sock_setattr(sk, &secattr); 61 if (rc == 0) { 62 spin_lock_bh(&sksec->nlbl_lock); 63 sksec->nlbl_state = NLBL_LABELED; 64 spin_unlock_bh(&sksec->nlbl_lock); 65 } 66 67 return rc; 68 } 69 70 /** 71 * selinux_netlbl_cache_invalidate - Invalidate the NetLabel cache 72 * 73 * Description: 74 * Invalidate the NetLabel security attribute mapping cache. 75 * 76 */ 77 void selinux_netlbl_cache_invalidate(void) 78 { 79 netlbl_cache_invalidate(); 80 } 81 82 /** 83 * selinux_netlbl_sk_security_reset - Reset the NetLabel fields 84 * @ssec: the sk_security_struct 85 * @family: the socket family 86 * 87 * Description: 88 * Called when the NetLabel state of a sk_security_struct needs to be reset. 89 * The caller is responsibile for all the NetLabel sk_security_struct locking. 90 * 91 */ 92 void selinux_netlbl_sk_security_reset(struct sk_security_struct *ssec, 93 int family) 94 { 95 if (family == PF_INET) 96 ssec->nlbl_state = NLBL_REQUIRE; 97 else 98 ssec->nlbl_state = NLBL_UNSET; 99 } 100 101 /** 102 * selinux_netlbl_sk_security_init - Setup the NetLabel fields 103 * @ssec: the sk_security_struct 104 * @family: the socket family 105 * 106 * Description: 107 * Called when a new sk_security_struct is allocated to initialize the NetLabel 108 * fields. 109 * 110 */ 111 void selinux_netlbl_sk_security_init(struct sk_security_struct *ssec, 112 int family) 113 { 114 /* No locking needed, we are the only one who has access to ssec */ 115 selinux_netlbl_sk_security_reset(ssec, family); 116 spin_lock_init(&ssec->nlbl_lock); 117 } 118 119 /** 120 * selinux_netlbl_sk_security_clone - Copy the NetLabel fields 121 * @ssec: the original sk_security_struct 122 * @newssec: the cloned sk_security_struct 123 * 124 * Description: 125 * Clone the NetLabel specific sk_security_struct fields from @ssec to 126 * @newssec. 127 * 128 */ 129 void selinux_netlbl_sk_security_clone(struct sk_security_struct *ssec, 130 struct sk_security_struct *newssec) 131 { 132 /* We don't need to take newssec->nlbl_lock because we are the only 133 * thread with access to newssec, but we do need to take the RCU read 134 * lock as other threads could have access to ssec */ 135 rcu_read_lock(); 136 selinux_netlbl_sk_security_reset(newssec, ssec->sk->sk_family); 137 newssec->sclass = ssec->sclass; 138 rcu_read_unlock(); 139 } 140 141 /** 142 * selinux_netlbl_skbuff_getsid - Get the sid of a packet using NetLabel 143 * @skb: the packet 144 * @base_sid: the SELinux SID to use as a context for MLS only attributes 145 * @sid: the SID 146 * 147 * Description: 148 * Call the NetLabel mechanism to get the security attributes of the given 149 * packet and use those attributes to determine the correct context/SID to 150 * assign to the packet. Returns zero on success, negative values on failure. 151 * 152 */ 153 int selinux_netlbl_skbuff_getsid(struct sk_buff *skb, u32 base_sid, u32 *sid) 154 { 155 int rc; 156 struct netlbl_lsm_secattr secattr; 157 158 if (!netlbl_enabled()) { 159 *sid = SECSID_NULL; 160 return 0; 161 } 162 163 netlbl_secattr_init(&secattr); 164 rc = netlbl_skbuff_getattr(skb, &secattr); 165 if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE) { 166 rc = security_netlbl_secattr_to_sid(&secattr, base_sid, sid); 167 if (rc == 0 && 168 (secattr.flags & NETLBL_SECATTR_CACHEABLE) && 169 (secattr.flags & NETLBL_SECATTR_CACHE)) 170 netlbl_cache_add(skb, &secattr); 171 } else 172 *sid = SECSID_NULL; 173 netlbl_secattr_destroy(&secattr); 174 175 return rc; 176 } 177 178 /** 179 * selinux_netlbl_sock_graft - Netlabel the new socket 180 * @sk: the new connection 181 * @sock: the new socket 182 * 183 * Description: 184 * The connection represented by @sk is being grafted onto @sock so set the 185 * socket's NetLabel to match the SID of @sk. 186 * 187 */ 188 void selinux_netlbl_sock_graft(struct sock *sk, struct socket *sock) 189 { 190 struct inode_security_struct *isec = SOCK_INODE(sock)->i_security; 191 struct sk_security_struct *sksec = sk->sk_security; 192 struct netlbl_lsm_secattr secattr; 193 u32 nlbl_peer_sid; 194 195 sksec->sclass = isec->sclass; 196 197 rcu_read_lock(); 198 199 if (sksec->nlbl_state != NLBL_REQUIRE) { 200 rcu_read_unlock(); 201 return; 202 } 203 204 netlbl_secattr_init(&secattr); 205 if (netlbl_sock_getattr(sk, &secattr) == 0 && 206 secattr.flags != NETLBL_SECATTR_NONE && 207 security_netlbl_secattr_to_sid(&secattr, 208 SECINITSID_NETMSG, 209 &nlbl_peer_sid) == 0) 210 sksec->peer_sid = nlbl_peer_sid; 211 netlbl_secattr_destroy(&secattr); 212 213 /* Try to set the NetLabel on the socket to save time later, if we fail 214 * here we will pick up the pieces in later calls to 215 * selinux_netlbl_inode_permission(). */ 216 selinux_netlbl_sock_setsid(sk, sksec->sid); 217 218 rcu_read_unlock(); 219 } 220 221 /** 222 * selinux_netlbl_socket_post_create - Label a socket using NetLabel 223 * @sock: the socket to label 224 * 225 * Description: 226 * Attempt to label a socket using the NetLabel mechanism using the given 227 * SID. Returns zero values on success, negative values on failure. 228 * 229 */ 230 int selinux_netlbl_socket_post_create(struct socket *sock) 231 { 232 int rc = 0; 233 struct sock *sk = sock->sk; 234 struct inode_security_struct *isec = SOCK_INODE(sock)->i_security; 235 struct sk_security_struct *sksec = sk->sk_security; 236 237 sksec->sclass = isec->sclass; 238 239 rcu_read_lock(); 240 if (sksec->nlbl_state == NLBL_REQUIRE) 241 rc = selinux_netlbl_sock_setsid(sk, sksec->sid); 242 rcu_read_unlock(); 243 244 return rc; 245 } 246 247 /** 248 * selinux_netlbl_inode_permission - Verify the socket is NetLabel labeled 249 * @inode: the file descriptor's inode 250 * @mask: the permission mask 251 * 252 * Description: 253 * Looks at a file's inode and if it is marked as a socket protected by 254 * NetLabel then verify that the socket has been labeled, if not try to label 255 * the socket now with the inode's SID. Returns zero on success, negative 256 * values on failure. 257 * 258 */ 259 int selinux_netlbl_inode_permission(struct inode *inode, int mask) 260 { 261 int rc; 262 struct sock *sk; 263 struct socket *sock; 264 struct sk_security_struct *sksec; 265 266 if (!S_ISSOCK(inode->i_mode) || 267 ((mask & (MAY_WRITE | MAY_APPEND)) == 0)) 268 return 0; 269 sock = SOCKET_I(inode); 270 sk = sock->sk; 271 sksec = sk->sk_security; 272 273 rcu_read_lock(); 274 if (sksec->nlbl_state != NLBL_REQUIRE) { 275 rcu_read_unlock(); 276 return 0; 277 } 278 local_bh_disable(); 279 bh_lock_sock_nested(sk); 280 rc = selinux_netlbl_sock_setsid(sk, sksec->sid); 281 bh_unlock_sock(sk); 282 local_bh_enable(); 283 rcu_read_unlock(); 284 285 return rc; 286 } 287 288 /** 289 * selinux_netlbl_sock_rcv_skb - Do an inbound access check using NetLabel 290 * @sksec: the sock's sk_security_struct 291 * @skb: the packet 292 * @ad: the audit data 293 * 294 * Description: 295 * Fetch the NetLabel security attributes from @skb and perform an access check 296 * against the receiving socket. Returns zero on success, negative values on 297 * error. 298 * 299 */ 300 int selinux_netlbl_sock_rcv_skb(struct sk_security_struct *sksec, 301 struct sk_buff *skb, 302 struct avc_audit_data *ad) 303 { 304 int rc; 305 u32 nlbl_sid; 306 u32 perm; 307 struct netlbl_lsm_secattr secattr; 308 309 if (!netlbl_enabled()) 310 return 0; 311 312 netlbl_secattr_init(&secattr); 313 rc = netlbl_skbuff_getattr(skb, &secattr); 314 if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE) { 315 rc = security_netlbl_secattr_to_sid(&secattr, 316 SECINITSID_NETMSG, 317 &nlbl_sid); 318 if (rc == 0 && 319 (secattr.flags & NETLBL_SECATTR_CACHEABLE) && 320 (secattr.flags & NETLBL_SECATTR_CACHE)) 321 netlbl_cache_add(skb, &secattr); 322 } else 323 nlbl_sid = SECINITSID_UNLABELED; 324 netlbl_secattr_destroy(&secattr); 325 if (rc != 0) 326 return rc; 327 328 switch (sksec->sclass) { 329 case SECCLASS_UDP_SOCKET: 330 perm = UDP_SOCKET__RECVFROM; 331 break; 332 case SECCLASS_TCP_SOCKET: 333 perm = TCP_SOCKET__RECVFROM; 334 break; 335 default: 336 perm = RAWIP_SOCKET__RECVFROM; 337 } 338 339 rc = avc_has_perm(sksec->sid, nlbl_sid, sksec->sclass, perm, ad); 340 if (rc == 0) 341 return 0; 342 343 if (nlbl_sid != SECINITSID_UNLABELED) 344 netlbl_skbuff_err(skb, rc); 345 return rc; 346 } 347 348 /** 349 * selinux_netlbl_socket_setsockopt - Do not allow users to remove a NetLabel 350 * @sock: the socket 351 * @level: the socket level or protocol 352 * @optname: the socket option name 353 * 354 * Description: 355 * Check the setsockopt() call and if the user is trying to replace the IP 356 * options on a socket and a NetLabel is in place for the socket deny the 357 * access; otherwise allow the access. Returns zero when the access is 358 * allowed, -EACCES when denied, and other negative values on error. 359 * 360 */ 361 int selinux_netlbl_socket_setsockopt(struct socket *sock, 362 int level, 363 int optname) 364 { 365 int rc = 0; 366 struct sock *sk = sock->sk; 367 struct sk_security_struct *sksec = sk->sk_security; 368 struct netlbl_lsm_secattr secattr; 369 370 rcu_read_lock(); 371 if (level == IPPROTO_IP && optname == IP_OPTIONS && 372 sksec->nlbl_state == NLBL_LABELED) { 373 netlbl_secattr_init(&secattr); 374 lock_sock(sk); 375 rc = netlbl_sock_getattr(sk, &secattr); 376 release_sock(sk); 377 if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE) 378 rc = -EACCES; 379 netlbl_secattr_destroy(&secattr); 380 } 381 rcu_read_unlock(); 382 383 return rc; 384 } 385