/* * SELinux NetLabel Support * * This file provides the necessary glue to tie NetLabel into the SELinux * subsystem. * * Author: Paul Moore <paul@paul-moore.com> * */ /* * (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, see <http://www.gnu.org/licenses/>. * */ #include <linux/spinlock.h> #include <linux/rcupdate.h> #include <linux/gfp.h> #include <linux/ip.h> #include <linux/ipv6.h> #include <net/sock.h> #include <net/netlabel.h> #include <net/ip.h> #include <net/ipv6.h> #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, u16 family, struct netlbl_lsm_secattr *secattr, u32 *sid) { int rc; rc = security_netlbl_secattr_to_sid(&selinux_state, secattr, sid); if (rc == 0 && (secattr->flags & NETLBL_SECATTR_CACHEABLE) && (secattr->flags & NETLBL_SECATTR_CACHE)) netlbl_cache_add(skb, family, 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(&selinux_state, sksec->sid, secattr); if (rc != 0) { netlbl_secattr_free(secattr); return NULL; } sksec->nlbl_secattr = secattr; return secattr; } /** * selinux_netlbl_sock_getattr - Get the cached NetLabel secattr * @sk: the socket * @sid: the SID * * Query the socket's cached secattr and if the SID matches the cached value * return the cache, otherwise return NULL. * */ static struct netlbl_lsm_secattr *selinux_netlbl_sock_getattr( const struct sock *sk, u32 sid) { struct sk_security_struct *sksec = sk->sk_security; struct netlbl_lsm_secattr *secattr = sksec->nlbl_secattr; if (secattr == NULL) return NULL; if ((secattr->flags & NETLBL_SECATTR_SECID) && (secattr->attr.secid == sid)) return secattr; return NULL; } /** * 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, u16 family, int error, int gateway) { netlbl_skbuff_err(skb, family, error, gateway); } /** * selinux_netlbl_sk_security_free - Free the NetLabel fields * @sksec: 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 *sksec) { if (sksec->nlbl_secattr != NULL) netlbl_secattr_free(sksec->nlbl_secattr); } /** * selinux_netlbl_sk_security_reset - Reset the NetLabel fields * @sksec: 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 responsible for all the NetLabel sk_security_struct locking. * */ void selinux_netlbl_sk_security_reset(struct sk_security_struct *sksec) { sksec->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, family, &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 success, 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_to_full_sk(skb); if (sk != NULL) { struct sk_security_struct *sksec = sk->sk_security; if (sksec->nlbl_state != NLBL_REQSKB) return 0; secattr = selinux_netlbl_sock_getattr(sk, sid); } if (secattr == NULL) { secattr = &secattr_storage; netlbl_secattr_init(secattr); rc = security_netlbl_sid_to_secattr(&selinux_state, 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_sctp_assoc_request - Label an incoming sctp association. * @ep: incoming association endpoint. * @skb: the packet. * * Description: * A new incoming connection is represented by @ep, ...... * Returns zero on success, negative values on failure. * */ int selinux_netlbl_sctp_assoc_request(struct sctp_endpoint *ep, struct sk_buff *skb) { int rc; struct netlbl_lsm_secattr secattr; struct sk_security_struct *sksec = ep->base.sk->sk_security; struct sockaddr *addr; struct sockaddr_in addr4; #if IS_ENABLED(CONFIG_IPV6) struct sockaddr_in6 addr6; #endif if (ep->base.sk->sk_family != PF_INET && ep->base.sk->sk_family != PF_INET6) return 0; netlbl_secattr_init(&secattr); rc = security_netlbl_sid_to_secattr(&selinux_state, ep->secid, &secattr); if (rc != 0) goto assoc_request_return; /* Move skb hdr address info to a struct sockaddr and then call * netlbl_conn_setattr(). */ if (ip_hdr(skb)->version == 4) { addr4.sin_family = AF_INET; addr4.sin_addr.s_addr = ip_hdr(skb)->saddr; addr = (struct sockaddr *)&addr4; #if IS_ENABLED(CONFIG_IPV6) } else { addr6.sin6_family = AF_INET6; addr6.sin6_addr = ipv6_hdr(skb)->saddr; addr = (struct sockaddr *)&addr6; #endif } rc = netlbl_conn_setattr(ep->base.sk, addr, &secattr); if (rc == 0) sksec->nlbl_state = NLBL_LABELED; assoc_request_return: netlbl_secattr_destroy(&secattr); return rc; } /** * selinux_netlbl_inet_conn_request - Label an incoming stream connection * @req: incoming connection request socket * * Description: * A new incoming connection request is represented by @req, we need to label * the new request_sock here and the stack will ensure the on-the-wire label * will get preserved when a full sock is created once the connection handshake * is complete. Returns zero on success, negative values on failure. * */ int selinux_netlbl_inet_conn_request(struct request_sock *req, u16 family) { int rc; struct netlbl_lsm_secattr secattr; if (family != PF_INET && family != PF_INET6) return 0; netlbl_secattr_init(&secattr); rc = security_netlbl_sid_to_secattr(&selinux_state, req->secid, &secattr); if (rc != 0) goto inet_conn_request_return; rc = netlbl_req_setattr(req, &secattr); inet_conn_request_return: netlbl_secattr_destroy(&secattr); return rc; } /** * selinux_netlbl_inet_csk_clone - Initialize the newly created sock * @sk: the new sock * * Description: * A new connection has been established using @sk, we've already labeled the * socket via the request_sock struct in selinux_netlbl_inet_conn_request() but * we need to set the NetLabel state here since we now have a sock structure. * */ void selinux_netlbl_inet_csk_clone(struct sock *sk, u16 family) { struct sk_security_struct *sksec = sk->sk_security; if (family == PF_INET) sksec->nlbl_state = NLBL_LABELED; else sksec->nlbl_state = NLBL_UNSET; } /** * selinux_netlbl_sctp_sk_clone - Copy state to the newly created sock * @sk: current sock * @newsk: the new sock * * Description: * Called whenever a new socket is created by accept(2) or sctp_peeloff(3). */ void selinux_netlbl_sctp_sk_clone(struct sock *sk, struct sock *newsk) { struct sk_security_struct *sksec = sk->sk_security; struct sk_security_struct *newsksec = newsk->sk_security; newsksec->nlbl_state = sksec->nlbl_state; } /** * selinux_netlbl_socket_post_create - Label a socket using NetLabel * @sock: the socket to label * @family: protocol family * * 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 sock *sk, u16 family) { int rc; struct sk_security_struct *sksec = sk->sk_security; struct netlbl_lsm_secattr *secattr; if (family != PF_INET && family != PF_INET6) return 0; secattr = selinux_netlbl_sock_genattr(sk); if (secattr == NULL) return -ENOMEM; rc = netlbl_sock_setattr(sk, family, 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_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 common_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, family, &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(&selinux_state, sksec->sid, nlbl_sid, sksec->sclass, perm, ad); if (rc == 0) return 0; if (nlbl_sid != SECINITSID_UNLABELED) netlbl_skbuff_err(skb, family, rc, 0); return rc; } /** * selinux_netlbl_option - Is this a NetLabel option * @level: the socket level or protocol * @optname: the socket option name * * Description: * Returns true if @level and @optname refer to a NetLabel option. * Helper for selinux_netlbl_socket_setsockopt(). */ static inline int selinux_netlbl_option(int level, int optname) { return (level == IPPROTO_IP && optname == IP_OPTIONS) || (level == IPPROTO_IPV6 && optname == IPV6_HOPOPTS); } /** * 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 (selinux_netlbl_option(level, optname) && (sksec->nlbl_state == NLBL_LABELED || sksec->nlbl_state == NLBL_CONNLABELED)) { netlbl_secattr_init(&secattr); lock_sock(sk); /* call the netlabel function directly as we want to see the * on-the-wire label that is assigned via the socket's options * and not the cached netlabel/lsm attributes */ 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_helper - Help 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. * */ static int selinux_netlbl_socket_connect_helper(struct sock *sk, struct sockaddr *addr) { int rc; struct sk_security_struct *sksec = sk->sk_security; struct netlbl_lsm_secattr *secattr; /* 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; return rc; } secattr = selinux_netlbl_sock_genattr(sk); if (secattr == NULL) { rc = -ENOMEM; return rc; } rc = netlbl_conn_setattr(sk, addr, secattr); if (rc == 0) sksec->nlbl_state = NLBL_CONNLABELED; return rc; } /** * selinux_netlbl_socket_connect_locked - Label a client-side socket on * connect * @sk: the socket to label * @addr: the destination address * * Description: * Attempt to label a connected socket that already has the socket locked * with NetLabel using the given address. * Returns zero values on success, negative values on failure. * */ int selinux_netlbl_socket_connect_locked(struct sock *sk, struct sockaddr *addr) { struct sk_security_struct *sksec = sk->sk_security; if (sksec->nlbl_state != NLBL_REQSKB && sksec->nlbl_state != NLBL_CONNLABELED) return 0; return selinux_netlbl_socket_connect_helper(sk, addr); } /** * 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; lock_sock(sk); rc = selinux_netlbl_socket_connect_locked(sk, addr); release_sock(sk); return rc; }