diff options
Diffstat (limited to 'security/selinux/netlabel.c')
| -rw-r--r-- | security/selinux/netlabel.c | 497 |
1 files changed, 497 insertions, 0 deletions
diff --git a/security/selinux/netlabel.c b/security/selinux/netlabel.c new file mode 100644 index 000000000..0364120d1 --- /dev/null +++ b/security/selinux/netlabel.c @@ -0,0 +1,497 @@ +/* + * 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, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + */ + +#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, + 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_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, int error, int gateway) +{ + netlbl_skbuff_err(skb, 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, &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->sk; + 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(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_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) + return 0; + + netlbl_secattr_init(&secattr); + rc = security_netlbl_sid_to_secattr(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_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) + 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, &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); + /* 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 - 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; + + lock_sock(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: + release_sock(sk); + return rc; +} |