authd: add rdns provider (compile-tested)

authd/Makefile.am

@@ -3,5 +3,11 @@ AM_CFLAGS=$(WARNFLAGS)
 AM_CPPFLAGS = -I../include -I../librb/include 
 
 
-authd_SOURCES = provider.c authd.c res.c reslib.c dns.c
+authd_SOURCES = provider.c \
+		authd.c \
+		res.c \
+		reslib.c \
+		dns.c \
+		providers/rdns.c
+
 authd_LDADD = ../librb/src/librb.la

authd/provider.c

@@ -66,17 +66,7 @@ void unload_provider(struct auth_provider *provider)
 /* Initalise all providers */
 void init_providers(void)
 {
-	rb_dlink_node *ptr;
-	struct auth_provider *provider;
-
-	RB_DLINK_FOREACH(ptr, auth_providers.head)
-	{
-		provider = ptr->data;
-
-		if(provider->init && !provider->init())
-			/* Provider failed to init, time to go */
-			exit(1);
-	}
+	load_provider(&rdns_provider);
 }
 
 /* Terminate all providers */
@@ -184,7 +174,7 @@ void notice_client(struct auth_client *auth, const char *notice)
 }
 
 /* Begin authenticating user */
-static void start_auth(const char *cid, const char *l_ip, const char *l_port, const char *c_ip, const char *c_port)
+static void start_auth(const char *cid, const char *l_ip, const char *l_port, const char *c_addr, const char *c_port)
 {
 	rb_dlink_node *ptr;
 	struct auth_provider *provider;
@@ -204,7 +194,7 @@ static void start_auth(const char *cid, const char *l_ip, const char *l_port, co
 	(void)rb_inet_pton_sock(l_ip, (struct sockaddr *)&auth->l_ip);
 	auth->l_port = (uint16_t)atoi(l_port); /* Safe cast, port shouldn't exceed 16 bits  */
 
-	(void)rb_inet_pton_sock(c_ip, (struct sockaddr *)&auth->c_ip);
+	(void)rb_inet_pton_sock(c_addr, (struct sockaddr *)&auth->c_addr);
 	auth->c_port = (uint16_t)atoi(c_port);
 
 	RB_DLINK_FOREACH(ptr, auth_providers.head)

authd/provider.h

@@ -42,7 +42,7 @@ struct auth_client
 	struct rb_sockaddr_storage l_ip;	/* Listener IP address */
 	uint16_t l_port;			/* Listener port */
 
-	struct rb_sockaddr_storage c_ip;	/* Client IP address */
+	struct rb_sockaddr_storage c_addr;	/* Client IP address */
 	uint16_t c_port;			/* Client port */
 
 	char hostname[HOSTLEN + 1];		/* Used for DNS lookup */
@@ -73,6 +73,7 @@ struct auth_provider
 };
 
 extern rb_dlink_list auth_providers;
+extern struct auth_provider rdns_provider;
 
 extern struct auth_client auth_clients[MAX_CLIENTS];
 

authd/providers/rdns.c

@@ -0,0 +1,226 @@
+/* authd/providers/rdns.c - rDNS lookup provider for authd
+ * Copyright (c) 2016 Elizabeth Myers <elizabeth@interlinked.me>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice is present in all copies.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "stdinc.h"
+#include "rb_commio.h"
+#include "authd.h"
+#include "provider.h"
+#include "res.h"
+#include "dns.h"
+
+struct dns_query
+{
+	rb_dlink_node node;
+
+	struct auth_client *auth;		/* Our client */
+	struct DNSQuery query;			/* DNS query */
+	time_t timeout;				/* When the request times out */
+};
+
+/* Goinked from old s_auth.c --Elizabeth */
+static const char *messages[] =
+{
+	"*** Looking up your hostname...",
+	"*** Found your hostname",
+	"*** Couldn't look up your hostname",
+	"*** Your hostname is too long, ignoring hostname",
+};
+
+typedef enum
+{
+	REPORT_LOOKUP,
+	REPORT_FOUND,
+	REPORT_FAIL,
+	REPORT_TOOLONG,
+} dns_message;
+
+static EVH timeout_dns_queries_event;
+static void client_fail(struct dns_query *query, dns_message message);
+static void client_success(struct dns_query *query);
+static void get_dns_answer(void *userdata, struct DNSReply *reply);
+
+rb_dlink_list queries;
+static struct ev_entry *timeout_ev;
+int timeout = 30;
+
+
+bool client_dns_init(void)
+{
+	timeout_ev = rb_event_addish("timeout_dns_queries_event", timeout_dns_queries_event, NULL, 1);
+	return (timeout_ev != NULL);
+}
+
+void client_dns_destroy(void)
+{
+	rb_dlink_node *ptr, *nptr;
+	struct dns_query *query;
+
+	RB_DLINK_FOREACH_SAFE(ptr, nptr, queries.head)
+	{
+		client_fail(ptr->data, REPORT_FAIL);
+		rb_dlinkDelete(ptr, &queries);
+		rb_free(ptr);
+	}
+
+	rb_event_delete(timeout_ev);
+}
+
+bool client_dns_start(struct auth_client *auth)
+{
+	struct dns_query *query = rb_malloc(sizeof(struct dns_query));
+
+	query->auth = auth;
+	query->timeout = rb_current_time() + timeout;
+
+	query->query.ptr = query;
+	query->query.callback = get_dns_answer;
+
+	gethost_byaddr(&auth->c_addr, &query->query);
+	notice_client(auth, messages[REPORT_LOOKUP]);
+	return true;
+}
+
+void client_dns_cancel(struct auth_client *auth)
+{
+	rb_dlink_node *ptr;
+
+	/* Bah, the stupid DNS resolver code doesn't have a cancellation
+	 * func... */
+	RB_DLINK_FOREACH(ptr, queries.head)
+	{
+		struct dns_query *query = ptr->data;
+
+		if(query->auth == auth)
+		{
+			/* This will get cleaned up later by the DNS stuff */
+			client_fail(query, REPORT_FAIL);
+			return;
+		}
+	}
+}
+
+static void
+get_dns_answer(void *userdata, struct DNSReply *reply)
+{
+	struct dns_query *query = userdata;
+	struct auth_client *auth = query->auth;
+	rb_dlink_node *ptr, *nptr;
+	bool fail = false;
+	dns_message response;
+
+	if(reply == NULL || auth == NULL)
+	{
+		response = REPORT_FAIL;
+		fail = true;
+		goto cleanup;
+	}
+
+	if(!sockcmp(&auth->c_addr, &reply->addr, GET_SS_FAMILY(&auth->c_addr)))
+	{
+		response = REPORT_FAIL;
+		fail = true;
+		goto cleanup;
+	}
+
+	if(strlen(reply->h_name) > HOSTLEN)
+	{
+		/* Ah well. */
+		response = REPORT_TOOLONG;
+		fail = true;
+		goto cleanup;
+	}
+
+	rb_strlcpy(auth->hostname, reply->h_name, HOSTLEN + 1);
+
+cleanup:
+	/* Clean us up off the pending queries list */
+	RB_DLINK_FOREACH_SAFE(ptr, nptr, queries.head)
+	{
+		struct dns_query *query_l = ptr->data;
+
+		if(query == query_l)
+		{
+			/* Found */
+			if(fail)
+				client_fail(query, response);
+			else
+				client_success(query);
+
+			rb_dlinkDelete(ptr, &queries);
+			rb_free(query);
+			return;
+		}
+	}
+}
+
+/* Timeout outstanding queries */
+static void timeout_dns_queries_event(void *notused)
+{
+	rb_dlink_node *ptr;
+
+	/* NOTE - we do not delete queries from the list from a timeout, when
+	 * the query times out later it will be deleted.
+	 */
+	RB_DLINK_FOREACH(ptr, queries.head)
+	{
+		struct dns_query *query = ptr->data;
+
+		if(query->auth && query->timeout < rb_current_time())
+		{
+			client_fail(query, REPORT_FAIL);
+			return;
+		}
+	}
+}
+
+static void client_fail(struct dns_query *query, dns_message report)
+{
+	struct auth_client *auth = query->auth;
+
+	if(auth)
+	{
+		rb_strlcpy(auth->hostname, "*", sizeof(auth->hostname));
+		notice_client(auth, messages[report]);
+		provider_done(auth, PROVIDER_RDNS);
+		query->auth = NULL;
+	}
+}
+
+static void client_success(struct dns_query *query)
+{
+	struct auth_client *auth = query->auth;
+
+	if(auth)
+	{
+		notice_client(auth, messages[REPORT_FOUND]);
+		provider_done(auth, PROVIDER_RDNS);
+		query->auth = NULL;
+	}
+}
+
+struct auth_provider rdns_provider =
+{
+	.id = PROVIDER_RDNS,
+	.init = client_dns_init,
+	.destroy = client_dns_destroy,
+	.start = client_dns_start,
+	.cancel = client_dns_cancel,
+	.completed = NULL,
+};