diff options
Diffstat (limited to 'security/selinux/netlabel.c')
| -rw-r--r-- | security/selinux/netlabel.c | 363 |
1 files changed, 363 insertions, 0 deletions
diff --git a/security/selinux/netlabel.c b/security/selinux/netlabel.c new file mode 100644 index 000000000000..bf8750791dd1 --- /dev/null +++ b/security/selinux/netlabel.c @@ -0,0 +1,363 @@ +/* + * SELinux NetLabel Support + * + * This file provides the necessary glue to tie NetLabel into the SELinux + * subsystem. + * + * Author: Paul Moore <paul.moore@hp.com> + * + */ + +/* + * (c) Copyright Hewlett-Packard Development Company, L.P., 2007 + * + * 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 <net/sock.h> +#include <net/netlabel.h> + +#include "objsec.h" +#include "security.h" + +/** + * selinux_netlbl_socket_setsid - Label a socket using the NetLabel mechanism + * @sock: the socket to label + * @sid: the SID to use + * + * Description: + * Attempt to label a socket using the NetLabel mechanism using the given + * SID. Returns zero values on success, negative values on failure. The + * caller is responsibile for calling rcu_read_lock() before calling this + * this function and rcu_read_unlock() after this function returns. + * + */ +static int selinux_netlbl_socket_setsid(struct socket *sock, u32 sid) +{ + int rc; + struct sk_security_struct *sksec = sock->sk->sk_security; + struct netlbl_lsm_secattr secattr; + + rc = security_netlbl_sid_to_secattr(sid, &secattr); + if (rc != 0) + return rc; + + rc = netlbl_socket_setattr(sock, &secattr); + if (rc == 0) { + spin_lock_bh(&sksec->nlbl_lock); + sksec->nlbl_state = NLBL_LABELED; + spin_unlock_bh(&sksec->nlbl_lock); + } + + 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_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_sk_security_init - Setup the NetLabel fields + * @ssec: the sk_security_struct + * @family: the socket family + * + * Description: + * Called when a new sk_security_struct is allocated to initialize the NetLabel + * fields. + * + */ +void selinux_netlbl_sk_security_init(struct sk_security_struct *ssec, + int family) +{ + /* No locking needed, we are the only one who has access to ssec */ + selinux_netlbl_sk_security_reset(ssec, family); + spin_lock_init(&ssec->nlbl_lock); +} + +/** + * selinux_netlbl_sk_security_clone - Copy the NetLabel fields + * @ssec: the original sk_security_struct + * @newssec: the cloned sk_security_struct + * + * Description: + * Clone the NetLabel specific sk_security_struct fields from @ssec to + * @newssec. + * + */ +void selinux_netlbl_sk_security_clone(struct sk_security_struct *ssec, + struct sk_security_struct *newssec) +{ + /* We don't need to take newssec->nlbl_lock because we are the only + * thread with access to newssec, but we do need to take the RCU read + * lock as other threads could have access to ssec */ + rcu_read_lock(); + selinux_netlbl_sk_security_reset(newssec, ssec->sk->sk_family); + newssec->sclass = ssec->sclass; + rcu_read_unlock(); +} + +/** + * selinux_netlbl_skbuff_getsid - Get the sid of a packet using NetLabel + * @skb: the packet + * @base_sid: the SELinux SID to use as a context for MLS only attributes + * @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, u32 base_sid, u32 *sid) +{ + int rc; + struct netlbl_lsm_secattr secattr; + + netlbl_secattr_init(&secattr); + rc = netlbl_skbuff_getattr(skb, &secattr); + if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE) + rc = security_netlbl_secattr_to_sid(&secattr, + base_sid, + sid); + else + *sid = SECSID_NULL; + netlbl_secattr_destroy(&secattr); + + return rc; +} + +/** + * selinux_netlbl_sock_graft - Netlabel the new socket + * @sk: the new connection + * @sock: the new socket + * + * Description: + * The connection represented by @sk is being grafted onto @sock so set the + * socket's NetLabel to match the SID of @sk. + * + */ +void selinux_netlbl_sock_graft(struct sock *sk, struct socket *sock) +{ + struct inode_security_struct *isec = SOCK_INODE(sock)->i_security; + struct sk_security_struct *sksec = sk->sk_security; + struct netlbl_lsm_secattr secattr; + u32 nlbl_peer_sid; + + sksec->sclass = isec->sclass; + + rcu_read_lock(); + + if (sksec->nlbl_state != NLBL_REQUIRE) { + rcu_read_unlock(); + return; + } + + netlbl_secattr_init(&secattr); + if (netlbl_sock_getattr(sk, &secattr) == 0 && + secattr.flags != NETLBL_SECATTR_NONE && + security_netlbl_secattr_to_sid(&secattr, + SECINITSID_UNLABELED, + &nlbl_peer_sid) == 0) + sksec->peer_sid = nlbl_peer_sid; + netlbl_secattr_destroy(&secattr); + + /* Try to set the NetLabel on the socket to save time later, if we fail + * here we will pick up the pieces in later calls to + * selinux_netlbl_inode_permission(). */ + selinux_netlbl_socket_setsid(sock, sksec->sid); + + rcu_read_unlock(); +} + +/** + * 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) +{ + int rc = 0; + struct inode_security_struct *isec = SOCK_INODE(sock)->i_security; + struct sk_security_struct *sksec = sock->sk->sk_security; + + sksec->sclass = isec->sclass; + + rcu_read_lock(); + if (sksec->nlbl_state == NLBL_REQUIRE) + rc = selinux_netlbl_socket_setsid(sock, sksec->sid); + rcu_read_unlock(); + + return rc; +} + +/** + * 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 sk_security_struct *sksec; + struct socket *sock; + + if (!S_ISSOCK(inode->i_mode) || + ((mask & (MAY_WRITE | MAY_APPEND)) == 0)) + return 0; + sock = SOCKET_I(inode); + sksec = sock->sk->sk_security; + + rcu_read_lock(); + if (sksec->nlbl_state != NLBL_REQUIRE) { + rcu_read_unlock(); + return 0; + } + local_bh_disable(); + bh_lock_sock_nested(sock->sk); + rc = selinux_netlbl_socket_setsid(sock, sksec->sid); + bh_unlock_sock(sock->sk); + local_bh_enable(); + rcu_read_unlock(); + + return rc; +} + +/** + * selinux_netlbl_sock_rcv_skb - Do an inbound access check using NetLabel + * @sksec: the sock's sk_security_struct + * @skb: the packet + * @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, + struct avc_audit_data *ad) +{ + int rc; + u32 netlbl_sid; + u32 recv_perm; + + rc = selinux_netlbl_skbuff_getsid(skb, + SECINITSID_UNLABELED, + &netlbl_sid); + if (rc != 0) + return rc; + + if (netlbl_sid == SECSID_NULL) + return 0; + + switch (sksec->sclass) { + case SECCLASS_UDP_SOCKET: + recv_perm = UDP_SOCKET__RECVFROM; + break; + case SECCLASS_TCP_SOCKET: + recv_perm = TCP_SOCKET__RECVFROM; + break; + default: + recv_perm = RAWIP_SOCKET__RECVFROM; + } + + rc = avc_has_perm(sksec->sid, + netlbl_sid, + sksec->sclass, + recv_perm, + ad); + if (rc == 0) + return 0; + + netlbl_skbuff_err(skb, rc); + 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 sk_security_struct *sksec = sock->sk->sk_security; + struct netlbl_lsm_secattr secattr; + + rcu_read_lock(); + if (level == IPPROTO_IP && optname == IP_OPTIONS && + sksec->nlbl_state == NLBL_LABELED) { + netlbl_secattr_init(&secattr); + rc = netlbl_socket_getattr(sock, &secattr); + if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE) + rc = -EACCES; + netlbl_secattr_destroy(&secattr); + } + rcu_read_unlock(); + + return rc; +} |