/* * SELinux NetLabel Support * * This file provides the necessary glue to tie NetLabel into the SELinux * subsystem. * * Author: Paul Moore * */ /* * (c) Copyright Hewlett-Packard Development Company, L.P., 2007, 2008 * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * 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. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * */ #include #include #include #include #include #include #include #include #include "objsec.h" #include "security.h" #include "netlabel.h" /** * selinux_netlbl_sidlookup_cached - Cache a SID lookup * @skb: the packet * @secattr: the NetLabel security attributes * @sid: the SID * * Description: * Query the SELinux security server to lookup the correct SID for the given * security attributes. If the query is successful, cache the result to speed * up future lookups. Returns zero on success, negative values on failure. * */ static int selinux_netlbl_sidlookup_cached(struct sk_buff *skb, struct netlbl_lsm_secattr *secattr, u32 *sid) { int rc; rc = security_netlbl_secattr_to_sid(secattr, sid); if (rc == 0 && (secattr->flags & NETLBL_SECATTR_CACHEABLE) && (secattr->flags & NETLBL_SECATTR_CACHE)) netlbl_cache_add(skb, secattr); return rc; } /** * selinux_netlbl_sock_genattr - Generate the NetLabel socket secattr * @sk: the socket * * Description: * Generate the NetLabel security attributes for a socket, making full use of * the socket's attribute cache. Returns a pointer to the security attributes * on success, NULL on failure. * */ static struct netlbl_lsm_secattr *selinux_netlbl_sock_genattr(struct sock *sk) { int rc; struct sk_security_struct *sksec = sk->sk_security; struct netlbl_lsm_secattr *secattr; if (sksec->nlbl_secattr != NULL) return sksec->nlbl_secattr; secattr = netlbl_secattr_alloc(GFP_ATOMIC); if (secattr == NULL) return NULL; rc = security_netlbl_sid_to_secattr(sksec->sid, secattr); if (rc != 0) { netlbl_secattr_free(secattr); return NULL; } sksec->nlbl_secattr = secattr; return secattr; } /** * selinux_netlbl_sock_setsid - Label a socket using the NetLabel mechanism * @sk: the socket to label * * Description: * Attempt to label a socket using the NetLabel mechanism. Returns zero values * on success, negative values on failure. * */ static int selinux_netlbl_sock_setsid(struct sock *sk) { int rc; struct sk_security_struct *sksec = sk->sk_security; struct netlbl_lsm_secattr *secattr; if (sksec->nlbl_state != NLBL_REQUIRE) return 0; secattr = selinux_netlbl_sock_genattr(sk); if (secattr == NULL) return -ENOMEM; rc = netlbl_sock_setattr(sk, secattr); switch (rc) { case 0: sksec->nlbl_state = NLBL_LABELED; break; case -EDESTADDRREQ: sksec->nlbl_state = NLBL_REQSKB; rc = 0; break; } return rc; } /** * selinux_netlbl_cache_invalidate - Invalidate the NetLabel cache * * Description: * Invalidate the NetLabel security attribute mapping cache. * */ void selinux_netlbl_cache_invalidate(void) { netlbl_cache_invalidate(); } /** * selinux_netlbl_err - Handle a NetLabel packet error * @skb: the packet * @error: the error code * @gateway: true if host is acting as a gateway, false otherwise * * Description: * When a packet is dropped due to a call to avc_has_perm() pass the error * code to the NetLabel subsystem so any protocol specific processing can be * done. This is safe to call even if you are unsure if NetLabel labeling is * present on the packet, NetLabel is smart enough to only act when it should. * */ void selinux_netlbl_err(struct sk_buff *skb, int error, int gateway) { netlbl_skbuff_err(skb, error, gateway); } /** * selinux_netlbl_sk_security_free - Free the NetLabel fields * @sssec: the sk_security_struct * * Description: * Free all of the memory in the NetLabel fields of a sk_security_struct. * */ void selinux_netlbl_sk_security_free(struct sk_security_struct *ssec) { if (ssec->nlbl_secattr != NULL) netlbl_secattr_free(ssec->nlbl_secattr); } /** * selinux_netlbl_sk_security_reset - Reset the NetLabel fields * @ssec: the sk_security_struct * @family: the socket family * * Description: * Called when the NetLabel state of a sk_security_struct needs to be reset. * The caller is responsibile for all the NetLabel sk_security_struct locking. * */ void selinux_netlbl_sk_security_reset(struct sk_security_struct *ssec, int family) { if (family == PF_INET) ssec->nlbl_state = NLBL_REQUIRE; else ssec->nlbl_state = NLBL_UNSET; } /** * selinux_netlbl_skbuff_getsid - Get the sid of a packet using NetLabel * @skb: the packet * @family: protocol family * @type: NetLabel labeling protocol type * @sid: the SID * * Description: * Call the NetLabel mechanism to get the security attributes of the given * packet and use those attributes to determine the correct context/SID to * assign to the packet. Returns zero on success, negative values on failure. * */ int selinux_netlbl_skbuff_getsid(struct sk_buff *skb, u16 family, u32 *type, u32 *sid) { int rc; struct netlbl_lsm_secattr secattr; if (!netlbl_enabled()) { *sid = SECSID_NULL; return 0; } netlbl_secattr_init(&secattr); rc = netlbl_skbuff_getattr(skb, family, &secattr); if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE) rc = selinux_netlbl_sidlookup_cached(skb, &secattr, sid); else *sid = SECSID_NULL; *type = secattr.type; netlbl_secattr_destroy(&secattr); return rc; } /** * selinux_netlbl_skbuff_setsid - Set the NetLabel on a packet given a sid * @skb: the packet * @family: protocol family * @sid: the SID * * Description * Call the NetLabel mechanism to set the label of a packet using @sid. * Returns zero on auccess, negative values on failure. * */ int selinux_netlbl_skbuff_setsid(struct sk_buff *skb, u16 family, u32 sid) { int rc; struct netlbl_lsm_secattr secattr_storage; struct netlbl_lsm_secattr *secattr = NULL; struct sock *sk; /* if this is a locally generated packet check to see if it is already * being labeled by it's parent socket, if it is just exit */ sk = skb->sk; if (sk != NULL) { struct sk_security_struct *sksec = sk->sk_security; if (sksec->nlbl_state != NLBL_REQSKB) return 0; secattr = sksec->nlbl_secattr; } if (secattr == NULL) { secattr = &secattr_storage; netlbl_secattr_init(secattr); rc = security_netlbl_sid_to_secattr(sid, secattr); if (rc != 0) goto skbuff_setsid_return; } rc = netlbl_skbuff_setattr(skb, family, secattr); skbuff_setsid_return: if (secattr == &secattr_storage) netlbl_secattr_destroy(secattr); return rc; } /** * selinux_netlbl_inet_conn_established - Netlabel the newly accepted connection * @sk: the new connection * * Description: * A new connection has been established on @sk so make sure it is labeled * correctly with the NetLabel susbsystem. * */ void selinux_netlbl_inet_conn_established(struct sock *sk, u16 family) { int rc; struct sk_security_struct *sksec = sk->sk_security; struct netlbl_lsm_secattr *secattr; struct inet_sock *sk_inet = inet_sk(sk); struct sockaddr_in addr; if (sksec->nlbl_state != NLBL_REQUIRE) return; secattr = selinux_netlbl_sock_genattr(sk); if (secattr == NULL) return; rc = netlbl_sock_setattr(sk, secattr); switch (rc) { case 0: sksec->nlbl_state = NLBL_LABELED; break; case -EDESTADDRREQ: /* no PF_INET6 support yet because we don't support any IPv6 * labeling protocols */ if (family != PF_INET) { sksec->nlbl_state = NLBL_UNSET; return; } addr.sin_family = family; addr.sin_addr.s_addr = sk_inet->daddr; if (netlbl_conn_setattr(sk, (struct sockaddr *)&addr, secattr) != 0) { /* we failed to label the connected socket (could be * for a variety of reasons, the actual "why" isn't * important here) so we have to go to our backup plan, * labeling the packets individually in the netfilter * local output hook. this is okay but we need to * adjust the MSS of the connection to take into * account any labeling overhead, since we don't know * the exact overhead at this point we'll use the worst * case value which is 40 bytes for IPv4 */ struct inet_connection_sock *sk_conn = inet_csk(sk); sk_conn->icsk_ext_hdr_len += 40 - (sk_inet->opt ? sk_inet->opt->optlen : 0); sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie); sksec->nlbl_state = NLBL_REQSKB; } else sksec->nlbl_state = NLBL_CONNLABELED; break; default: /* note that we are failing to label the socket which could be * a bad thing since it means traffic could leave the system * without the desired labeling, however, all is not lost as * we have a check in selinux_netlbl_inode_permission() to * pick up the pieces that we might drop here because we can't * return an error code */ break; } } /** * selinux_netlbl_socket_post_create - Label a socket using NetLabel * @sock: the socket to label * * Description: * Attempt to label a socket using the NetLabel mechanism using the given * SID. Returns zero values on success, negative values on failure. * */ int selinux_netlbl_socket_post_create(struct socket *sock) { return selinux_netlbl_sock_setsid(sock->sk); } /** * selinux_netlbl_inode_permission - Verify the socket is NetLabel labeled * @inode: the file descriptor's inode * @mask: the permission mask * * Description: * Looks at a file's inode and if it is marked as a socket protected by * NetLabel then verify that the socket has been labeled, if not try to label * the socket now with the inode's SID. Returns zero on success, negative * values on failure. * */ int selinux_netlbl_inode_permission(struct inode *inode, int mask) { int rc; struct sock *sk; struct socket *sock; struct sk_security_struct *sksec; if (!S_ISSOCK(inode->i_mode) || ((mask & (MAY_WRITE | MAY_APPEND)) == 0)) return 0; sock = SOCKET_I(inode); sk = sock->sk; if (sk == NULL) return 0; sksec = sk->sk_security; if (sksec == NULL || sksec->nlbl_state != NLBL_REQUIRE) return 0; local_bh_disable(); bh_lock_sock_nested(sk); if (likely(sksec->nlbl_state == NLBL_REQUIRE)) rc = selinux_netlbl_sock_setsid(sk); else rc = 0; bh_unlock_sock(sk); local_bh_enable(); return rc; } /** * selinux_netlbl_sock_rcv_skb - Do an inbound access check using NetLabel * @sksec: the sock's sk_security_struct * @skb: the packet * @family: protocol family * @ad: the audit data * * Description: * Fetch the NetLabel security attributes from @skb and perform an access check * against the receiving socket. Returns zero on success, negative values on * error. * */ int selinux_netlbl_sock_rcv_skb(struct sk_security_struct *sksec, struct sk_buff *skb, u16 family, struct avc_audit_data *ad) { int rc; u32 nlbl_sid; u32 perm; struct netlbl_lsm_secattr secattr; if (!netlbl_enabled()) return 0; netlbl_secattr_init(&secattr); rc = netlbl_skbuff_getattr(skb, family, &secattr); if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE) rc = selinux_netlbl_sidlookup_cached(skb, &secattr, &nlbl_sid); else nlbl_sid = SECINITSID_UNLABELED; netlbl_secattr_destroy(&secattr); if (rc != 0) return rc; switch (sksec->sclass) { case SECCLASS_UDP_SOCKET: perm = UDP_SOCKET__RECVFROM; break; case SECCLASS_TCP_SOCKET: perm = TCP_SOCKET__RECVFROM; break; default: perm = RAWIP_SOCKET__RECVFROM; } rc = avc_has_perm(sksec->sid, nlbl_sid, sksec->sclass, perm, ad); if (rc == 0) return 0; if (nlbl_sid != SECINITSID_UNLABELED) netlbl_skbuff_err(skb, rc, 0); return rc; } /** * selinux_netlbl_socket_setsockopt - Do not allow users to remove a NetLabel * @sock: the socket * @level: the socket level or protocol * @optname: the socket option name * * Description: * Check the setsockopt() call and if the user is trying to replace the IP * options on a socket and a NetLabel is in place for the socket deny the * access; otherwise allow the access. Returns zero when the access is * allowed, -EACCES when denied, and other negative values on error. * */ int selinux_netlbl_socket_setsockopt(struct socket *sock, int level, int optname) { int rc = 0; struct sock *sk = sock->sk; struct sk_security_struct *sksec = sk->sk_security; struct netlbl_lsm_secattr secattr; if (level == IPPROTO_IP && optname == IP_OPTIONS && (sksec->nlbl_state == NLBL_LABELED || sksec->nlbl_state == NLBL_CONNLABELED)) { netlbl_secattr_init(&secattr); lock_sock(sk); rc = netlbl_sock_getattr(sk, &secattr); release_sock(sk); if (rc == 0) rc = -EACCES; else if (rc == -ENOMSG) rc = 0; netlbl_secattr_destroy(&secattr); } return rc; } /** * selinux_netlbl_socket_connect - Label a client-side socket on connect * @sk: the socket to label * @addr: the destination address * * Description: * Attempt to label a connected socket with NetLabel using the given address. * Returns zero values on success, negative values on failure. * */ int selinux_netlbl_socket_connect(struct sock *sk, struct sockaddr *addr) { int rc; struct sk_security_struct *sksec = sk->sk_security; struct netlbl_lsm_secattr *secattr; if (sksec->nlbl_state != NLBL_REQSKB && sksec->nlbl_state != NLBL_CONNLABELED) return 0; local_bh_disable(); bh_lock_sock_nested(sk); /* connected sockets are allowed to disconnect when the address family * is set to AF_UNSPEC, if that is what is happening we want to reset * the socket */ if (addr->sa_family == AF_UNSPEC) { netlbl_sock_delattr(sk); sksec->nlbl_state = NLBL_REQSKB; rc = 0; goto socket_connect_return; } secattr = selinux_netlbl_sock_genattr(sk); if (secattr == NULL) { rc = -ENOMEM; goto socket_connect_return; } rc = netlbl_conn_setattr(sk, addr, secattr); if (rc == 0) sksec->nlbl_state = NLBL_CONNLABELED; socket_connect_return: bh_unlock_sock(sk); local_bh_enable(); return rc; }