+
+/**
+ * security_skb_extlbl_sid - Determine the external label of a packet
+ * @skb: the packet
+ * @base_sid: the SELinux SID to use as a context for MLS only external labels
+ * @sid: the packet's SID
+ *
+ * Description:
+ * Check the various different forms of external packet labeling and determine
+ * the external SID for the packet.
+ *
+ */
+void security_skb_extlbl_sid(struct sk_buff *skb, u32 base_sid, u32 *sid)
+{
+ u32 xfrm_sid;
+ u32 nlbl_sid;
+
+ selinux_skb_xfrm_sid(skb, &xfrm_sid);
+ if (selinux_netlbl_skbuff_getsid(skb,
+ (xfrm_sid == SECSID_NULL ?
+ base_sid : xfrm_sid),
+ &nlbl_sid) != 0)
+ nlbl_sid = SECSID_NULL;
+
+ *sid = (nlbl_sid == SECSID_NULL ? xfrm_sid : nlbl_sid);
+}
+
+#ifdef CONFIG_NETLABEL
+/*
+ * This is the structure we store inside the NetLabel cache block.
+ */
+#define NETLBL_CACHE(x) ((struct netlbl_cache *)(x))
+#define NETLBL_CACHE_T_NONE 0
+#define NETLBL_CACHE_T_SID 1
+#define NETLBL_CACHE_T_MLS 2
+struct netlbl_cache {
+ u32 type;
+ union {
+ u32 sid;
+ struct mls_range mls_label;
+ } data;
+};
+
+/**
+ * selinux_netlbl_cache_free - Free the NetLabel cached data
+ * @data: the data to free
+ *
+ * Description:
+ * This function is intended to be used as the free() callback inside the
+ * netlbl_lsm_cache structure.
+ *
+ */
+static void selinux_netlbl_cache_free(const void *data)
+{
+ struct netlbl_cache *cache;
+
+ if (data == NULL)
+ return;
+
+ cache = NETLBL_CACHE(data);
+ switch (cache->type) {
+ case NETLBL_CACHE_T_MLS:
+ ebitmap_destroy(&cache->data.mls_label.level[0].cat);
+ break;
+ }
+ kfree(data);
+}
+
+/**
+ * selinux_netlbl_cache_add - Add an entry to the NetLabel cache
+ * @skb: the packet
+ * @ctx: the SELinux context
+ *
+ * Description:
+ * Attempt to cache the context in @ctx, which was derived from the packet in
+ * @skb, in the NetLabel subsystem cache.
+ *
+ */
+static void selinux_netlbl_cache_add(struct sk_buff *skb, struct context *ctx)
+{
+ struct netlbl_cache *cache = NULL;
+ struct netlbl_lsm_secattr secattr;
+
+ netlbl_secattr_init(&secattr);
+ secattr.cache = netlbl_secattr_cache_alloc(GFP_ATOMIC);
+ if (secattr.cache == NULL)
+ goto netlbl_cache_add_return;
+
+ cache = kzalloc(sizeof(*cache), GFP_ATOMIC);
+ if (cache == NULL)
+ goto netlbl_cache_add_return;
+
+ cache->type = NETLBL_CACHE_T_MLS;
+ if (ebitmap_cpy(&cache->data.mls_label.level[0].cat,
+ &ctx->range.level[0].cat) != 0)
+ goto netlbl_cache_add_return;
+ cache->data.mls_label.level[1].cat.highbit =
+ cache->data.mls_label.level[0].cat.highbit;
+ cache->data.mls_label.level[1].cat.node =
+ cache->data.mls_label.level[0].cat.node;
+ cache->data.mls_label.level[0].sens = ctx->range.level[0].sens;
+ cache->data.mls_label.level[1].sens = ctx->range.level[0].sens;
+
+ secattr.cache->free = selinux_netlbl_cache_free;
+ secattr.cache->data = (void *)cache;
+ secattr.flags = NETLBL_SECATTR_CACHE;
+
+ netlbl_cache_add(skb, &secattr);
+
+netlbl_cache_add_return:
+ netlbl_secattr_destroy(&secattr);
+}
+
+/**
+ * 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_secattr_to_sid - Convert a NetLabel secattr to a SELinux SID
+ * @skb: the network packet
+ * @secattr: the NetLabel packet security attributes
+ * @base_sid: the SELinux SID to use as a context for MLS only attributes
+ * @sid: the SELinux SID
+ *
+ * Description:
+ * Convert the given NetLabel packet security attributes in @secattr into a
+ * SELinux SID. If the @secattr field does not contain a full SELinux
+ * SID/context then use the context in @base_sid as the foundation. If @skb
+ * is not NULL attempt to cache as much data as possibile. Returns zero on
+ * success, negative values on failure.
+ *
+ */
+static int selinux_netlbl_secattr_to_sid(struct sk_buff *skb,
+ struct netlbl_lsm_secattr *secattr,
+ u32 base_sid,
+ u32 *sid)
+{
+ int rc = -EIDRM;
+ struct context *ctx;
+ struct context ctx_new;
+ struct netlbl_cache *cache;
+
+ POLICY_RDLOCK;
+
+ if (secattr->flags & NETLBL_SECATTR_CACHE) {
+ cache = NETLBL_CACHE(secattr->cache->data);
+ switch (cache->type) {
+ case NETLBL_CACHE_T_SID:
+ *sid = cache->data.sid;
+ rc = 0;
+ break;
+ case NETLBL_CACHE_T_MLS:
+ ctx = sidtab_search(&sidtab, base_sid);
+ if (ctx == NULL)
+ goto netlbl_secattr_to_sid_return;
+
+ ctx_new.user = ctx->user;
+ ctx_new.role = ctx->role;
+ ctx_new.type = ctx->type;
+ ctx_new.range.level[0].sens =
+ cache->data.mls_label.level[0].sens;
+ ctx_new.range.level[0].cat.highbit =
+ cache->data.mls_label.level[0].cat.highbit;
+ ctx_new.range.level[0].cat.node =
+ cache->data.mls_label.level[0].cat.node;
+ ctx_new.range.level[1].sens =
+ cache->data.mls_label.level[1].sens;
+ ctx_new.range.level[1].cat.highbit =
+ cache->data.mls_label.level[1].cat.highbit;
+ ctx_new.range.level[1].cat.node =
+ cache->data.mls_label.level[1].cat.node;
+
+ rc = sidtab_context_to_sid(&sidtab, &ctx_new, sid);
+ break;
+ default:
+ goto netlbl_secattr_to_sid_return;
+ }
+ } else if (secattr->flags & NETLBL_SECATTR_MLS_LVL) {
+ ctx = sidtab_search(&sidtab, base_sid);
+ if (ctx == NULL)
+ goto netlbl_secattr_to_sid_return;
+
+ ctx_new.user = ctx->user;
+ ctx_new.role = ctx->role;
+ ctx_new.type = ctx->type;
+ mls_import_netlbl_lvl(&ctx_new, secattr);
+ if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
+ if (ebitmap_netlbl_import(&ctx_new.range.level[0].cat,
+ secattr->mls_cat) != 0)
+ goto netlbl_secattr_to_sid_return;
+ ctx_new.range.level[1].cat.highbit =
+ ctx_new.range.level[0].cat.highbit;
+ ctx_new.range.level[1].cat.node =
+ ctx_new.range.level[0].cat.node;
+ } else {
+ ebitmap_init(&ctx_new.range.level[0].cat);
+ ebitmap_init(&ctx_new.range.level[1].cat);
+ }
+ if (mls_context_isvalid(&policydb, &ctx_new) != 1)
+ goto netlbl_secattr_to_sid_return_cleanup;
+
+ rc = sidtab_context_to_sid(&sidtab, &ctx_new, sid);
+ if (rc != 0)
+ goto netlbl_secattr_to_sid_return_cleanup;
+
+ if (skb != NULL)
+ selinux_netlbl_cache_add(skb, &ctx_new);
+ ebitmap_destroy(&ctx_new.range.level[0].cat);
+ } else {
+ *sid = SECSID_NULL;
+ rc = 0;
+ }
+
+netlbl_secattr_to_sid_return:
+ POLICY_RDUNLOCK;
+ return rc;
+netlbl_secattr_to_sid_return_cleanup:
+ ebitmap_destroy(&ctx_new.range.level[0].cat);
+ goto netlbl_secattr_to_sid_return;
+}
+
+/**
+ * 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 = selinux_netlbl_secattr_to_sid(skb,
+ &secattr,
+ base_sid,
+ sid);
+ else
+ *sid = SECSID_NULL;
+ netlbl_secattr_destroy(&secattr);
+
+ return rc;
+}
+
+/**
+ * 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 = -ENOENT;
+ struct sk_security_struct *sksec = sock->sk->sk_security;
+ struct netlbl_lsm_secattr secattr;
+ struct context *ctx;
+
+ if (!ss_initialized)
+ return 0;
+
+ netlbl_secattr_init(&secattr);
+
+ POLICY_RDLOCK;
+
+ ctx = sidtab_search(&sidtab, sid);
+ if (ctx == NULL)
+ goto netlbl_socket_setsid_return;
+
+ secattr.domain = kstrdup(policydb.p_type_val_to_name[ctx->type - 1],
+ GFP_ATOMIC);
+ secattr.flags |= NETLBL_SECATTR_DOMAIN;
+ mls_export_netlbl_lvl(ctx, &secattr);
+ rc = mls_export_netlbl_cat(ctx, &secattr);
+ if (rc != 0)
+ goto netlbl_socket_setsid_return;
+
+ 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);
+ }
+
+netlbl_socket_setsid_return:
+ POLICY_RDUNLOCK;
+ netlbl_secattr_destroy(&secattr);
+ return rc;
+}
+
+/**
+ * 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_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_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 &&
+ selinux_netlbl_secattr_to_sid(NULL,
+ &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_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;
+}
+#endif /* CONFIG_NETLABEL */