Paul Moore | 5778eab | 2007-02-28 15:14:22 -0500 | [diff] [blame] | 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_socket_setsid - Label a socket using the NetLabel mechanism |
| 40 | * @sock: 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_socket_setsid(struct socket *sock, u32 sid) |
| 51 | { |
| 52 | int rc; |
| 53 | struct sk_security_struct *sksec = sock->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_socket_setattr(sock, &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 | netlbl_secattr_init(&secattr); |
| 159 | rc = netlbl_skbuff_getattr(skb, &secattr); |
| 160 | if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE) |
| 161 | rc = security_netlbl_secattr_to_sid(&secattr, |
| 162 | base_sid, |
| 163 | sid); |
| 164 | else |
| 165 | *sid = SECSID_NULL; |
| 166 | netlbl_secattr_destroy(&secattr); |
| 167 | |
| 168 | return rc; |
| 169 | } |
| 170 | |
| 171 | /** |
| 172 | * selinux_netlbl_sock_graft - Netlabel the new socket |
| 173 | * @sk: the new connection |
| 174 | * @sock: the new socket |
| 175 | * |
| 176 | * Description: |
| 177 | * The connection represented by @sk is being grafted onto @sock so set the |
| 178 | * socket's NetLabel to match the SID of @sk. |
| 179 | * |
| 180 | */ |
| 181 | void selinux_netlbl_sock_graft(struct sock *sk, struct socket *sock) |
| 182 | { |
| 183 | struct inode_security_struct *isec = SOCK_INODE(sock)->i_security; |
| 184 | struct sk_security_struct *sksec = sk->sk_security; |
| 185 | struct netlbl_lsm_secattr secattr; |
| 186 | u32 nlbl_peer_sid; |
| 187 | |
| 188 | sksec->sclass = isec->sclass; |
| 189 | |
| 190 | rcu_read_lock(); |
| 191 | |
| 192 | if (sksec->nlbl_state != NLBL_REQUIRE) { |
| 193 | rcu_read_unlock(); |
| 194 | return; |
| 195 | } |
| 196 | |
| 197 | netlbl_secattr_init(&secattr); |
| 198 | if (netlbl_sock_getattr(sk, &secattr) == 0 && |
| 199 | secattr.flags != NETLBL_SECATTR_NONE && |
| 200 | security_netlbl_secattr_to_sid(&secattr, |
| 201 | SECINITSID_UNLABELED, |
| 202 | &nlbl_peer_sid) == 0) |
| 203 | sksec->peer_sid = nlbl_peer_sid; |
| 204 | netlbl_secattr_destroy(&secattr); |
| 205 | |
| 206 | /* Try to set the NetLabel on the socket to save time later, if we fail |
| 207 | * here we will pick up the pieces in later calls to |
| 208 | * selinux_netlbl_inode_permission(). */ |
| 209 | selinux_netlbl_socket_setsid(sock, sksec->sid); |
| 210 | |
| 211 | rcu_read_unlock(); |
| 212 | } |
| 213 | |
| 214 | /** |
| 215 | * selinux_netlbl_socket_post_create - Label a socket using NetLabel |
| 216 | * @sock: the socket to label |
| 217 | * |
| 218 | * Description: |
| 219 | * Attempt to label a socket using the NetLabel mechanism using the given |
| 220 | * SID. Returns zero values on success, negative values on failure. |
| 221 | * |
| 222 | */ |
| 223 | int selinux_netlbl_socket_post_create(struct socket *sock) |
| 224 | { |
| 225 | int rc = 0; |
| 226 | struct inode_security_struct *isec = SOCK_INODE(sock)->i_security; |
| 227 | struct sk_security_struct *sksec = sock->sk->sk_security; |
| 228 | |
| 229 | sksec->sclass = isec->sclass; |
| 230 | |
| 231 | rcu_read_lock(); |
| 232 | if (sksec->nlbl_state == NLBL_REQUIRE) |
| 233 | rc = selinux_netlbl_socket_setsid(sock, sksec->sid); |
| 234 | rcu_read_unlock(); |
| 235 | |
| 236 | return rc; |
| 237 | } |
| 238 | |
| 239 | /** |
| 240 | * selinux_netlbl_inode_permission - Verify the socket is NetLabel labeled |
| 241 | * @inode: the file descriptor's inode |
| 242 | * @mask: the permission mask |
| 243 | * |
| 244 | * Description: |
| 245 | * Looks at a file's inode and if it is marked as a socket protected by |
| 246 | * NetLabel then verify that the socket has been labeled, if not try to label |
| 247 | * the socket now with the inode's SID. Returns zero on success, negative |
| 248 | * values on failure. |
| 249 | * |
| 250 | */ |
| 251 | int selinux_netlbl_inode_permission(struct inode *inode, int mask) |
| 252 | { |
| 253 | int rc; |
| 254 | struct sk_security_struct *sksec; |
| 255 | struct socket *sock; |
| 256 | |
| 257 | if (!S_ISSOCK(inode->i_mode) || |
| 258 | ((mask & (MAY_WRITE | MAY_APPEND)) == 0)) |
| 259 | return 0; |
| 260 | sock = SOCKET_I(inode); |
| 261 | sksec = sock->sk->sk_security; |
| 262 | |
| 263 | rcu_read_lock(); |
| 264 | if (sksec->nlbl_state != NLBL_REQUIRE) { |
| 265 | rcu_read_unlock(); |
| 266 | return 0; |
| 267 | } |
| 268 | local_bh_disable(); |
| 269 | bh_lock_sock_nested(sock->sk); |
| 270 | rc = selinux_netlbl_socket_setsid(sock, sksec->sid); |
| 271 | bh_unlock_sock(sock->sk); |
| 272 | local_bh_enable(); |
| 273 | rcu_read_unlock(); |
| 274 | |
| 275 | return rc; |
| 276 | } |
| 277 | |
| 278 | /** |
| 279 | * selinux_netlbl_sock_rcv_skb - Do an inbound access check using NetLabel |
| 280 | * @sksec: the sock's sk_security_struct |
| 281 | * @skb: the packet |
| 282 | * @ad: the audit data |
| 283 | * |
| 284 | * Description: |
| 285 | * Fetch the NetLabel security attributes from @skb and perform an access check |
| 286 | * against the receiving socket. Returns zero on success, negative values on |
| 287 | * error. |
| 288 | * |
| 289 | */ |
| 290 | int selinux_netlbl_sock_rcv_skb(struct sk_security_struct *sksec, |
| 291 | struct sk_buff *skb, |
| 292 | struct avc_audit_data *ad) |
| 293 | { |
| 294 | int rc; |
| 295 | u32 netlbl_sid; |
| 296 | u32 recv_perm; |
| 297 | |
| 298 | rc = selinux_netlbl_skbuff_getsid(skb, |
| 299 | SECINITSID_UNLABELED, |
| 300 | &netlbl_sid); |
| 301 | if (rc != 0) |
| 302 | return rc; |
| 303 | |
| 304 | if (netlbl_sid == SECSID_NULL) |
| 305 | return 0; |
| 306 | |
| 307 | switch (sksec->sclass) { |
| 308 | case SECCLASS_UDP_SOCKET: |
| 309 | recv_perm = UDP_SOCKET__RECVFROM; |
| 310 | break; |
| 311 | case SECCLASS_TCP_SOCKET: |
| 312 | recv_perm = TCP_SOCKET__RECVFROM; |
| 313 | break; |
| 314 | default: |
| 315 | recv_perm = RAWIP_SOCKET__RECVFROM; |
| 316 | } |
| 317 | |
| 318 | rc = avc_has_perm(sksec->sid, |
| 319 | netlbl_sid, |
| 320 | sksec->sclass, |
| 321 | recv_perm, |
| 322 | ad); |
| 323 | if (rc == 0) |
| 324 | return 0; |
| 325 | |
| 326 | netlbl_skbuff_err(skb, rc); |
| 327 | return rc; |
| 328 | } |
| 329 | |
| 330 | /** |
| 331 | * selinux_netlbl_socket_setsockopt - Do not allow users to remove a NetLabel |
| 332 | * @sock: the socket |
| 333 | * @level: the socket level or protocol |
| 334 | * @optname: the socket option name |
| 335 | * |
| 336 | * Description: |
| 337 | * Check the setsockopt() call and if the user is trying to replace the IP |
| 338 | * options on a socket and a NetLabel is in place for the socket deny the |
| 339 | * access; otherwise allow the access. Returns zero when the access is |
| 340 | * allowed, -EACCES when denied, and other negative values on error. |
| 341 | * |
| 342 | */ |
| 343 | int selinux_netlbl_socket_setsockopt(struct socket *sock, |
| 344 | int level, |
| 345 | int optname) |
| 346 | { |
| 347 | int rc = 0; |
| 348 | struct sk_security_struct *sksec = sock->sk->sk_security; |
| 349 | struct netlbl_lsm_secattr secattr; |
| 350 | |
| 351 | rcu_read_lock(); |
| 352 | if (level == IPPROTO_IP && optname == IP_OPTIONS && |
| 353 | sksec->nlbl_state == NLBL_LABELED) { |
| 354 | netlbl_secattr_init(&secattr); |
| 355 | rc = netlbl_socket_getattr(sock, &secattr); |
| 356 | if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE) |
| 357 | rc = -EACCES; |
| 358 | netlbl_secattr_destroy(&secattr); |
| 359 | } |
| 360 | rcu_read_unlock(); |
| 361 | |
| 362 | return rc; |
| 363 | } |