1 files changed, 615 insertions, 0 deletions
diff --git a/security/selinux/netlabel.c b/security/selinux/netlabel.c
new file mode 100644
index 000000000..8f182800e
--- /dev/null
+++ b/security/selinux/netlabel.c
@@ -0,0 +1,615 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * 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
+ */
+
+#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
+ * @family: the packet's address family
+ * @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(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(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
+ * @family: the packet's address family
+ * @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)
+		return;
+
+	netlbl_secattr_free(sksec->nlbl_secattr);
+	sksec->nlbl_secattr = NULL;
+	sksec->nlbl_state = NLBL_UNSET;
+}
+
+/**
+ * selinux_netlbl_sk_security_reset - Reset the NetLabel fields
+ * @sksec: the sk_security_struct
+ *
+ * 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()) {
+		*type = NETLBL_NLTYPE_NONE;
+		*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(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.
+ * @asoc: incoming association.
+ * @skb: the packet.
+ *
+ * Description:
+ * A new incoming connection is represented by @asoc, ......
+ * Returns zero on success, negative values on failure.
+ *
+ */
+int selinux_netlbl_sctp_assoc_request(struct sctp_association *asoc,
+				     struct sk_buff *skb)
+{
+	int rc;
+	struct netlbl_lsm_secattr secattr;
+	struct sk_security_struct *sksec = asoc->base.sk->sk_security;
+	struct sockaddr_in addr4;
+	struct sockaddr_in6 addr6;
+
+	if (asoc->base.sk->sk_family != PF_INET &&
+	    asoc->base.sk->sk_family != PF_INET6)
+		return 0;
+
+	netlbl_secattr_init(&secattr);
+	rc = security_netlbl_sid_to_secattr(asoc->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;
+		rc = netlbl_conn_setattr(asoc->base.sk, (void *)&addr4, &secattr);
+	} else if (IS_ENABLED(CONFIG_IPV6) && ip_hdr(skb)->version == 6) {
+		addr6.sin6_family = AF_INET6;
+		addr6.sin6_addr = ipv6_hdr(skb)->saddr;
+		rc = netlbl_conn_setattr(asoc->base.sk, (void *)&addr6, &secattr);
+	} else {
+		rc = -EAFNOSUPPORT;
+	}
+
+	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
+ * @family: the request socket's address family
+ *
+ * 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(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
+ * @family: the sock's address family
+ *
+ * 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
+ * @sk: the sock 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(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;
+}