1 files changed, 713 insertions, 0 deletions

diff --git a/src/main/state.c b/src/main/state.c
new file mode 100644
index 0000000..3700062
--- /dev/null
+++ b/src/main/state.c
@@ -0,0 +1,713 @@
+/*
+ *   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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
+ */
+
+/**
+ * $Id$
+ *
+ * @brief Multi-packet state handling
+ * @file main/state.c
+ *
+ * @ingroup AVP
+ *
+ * @copyright 2014 The FreeRADIUS server project
+ */
+RCSID("$Id$")
+
+#include <freeradius-devel/radiusd.h>
+#include <freeradius-devel/state.h>
+#include <freeradius-devel/md5.h>
+#include <freeradius-devel/rad_assert.h>
+#include <freeradius-devel/process.h>
+
+typedef struct state_entry_t {
+	uint8_t		state[AUTH_VECTOR_LEN];
+
+	time_t		cleanup;
+	struct state_entry_t *prev;
+	struct state_entry_t *next;
+
+	int		tries;
+
+	TALLOC_CTX		*ctx;
+	VALUE_PAIR		*vps;
+
+	char		*server;
+	unsigned int	request_number;
+	RADCLIENT	*request_client;
+	main_config_t	*request_root;
+
+	void 		*opaque;
+	void 		(*free_opaque)(void *opaque);
+} state_entry_t;
+
+struct fr_state_t {
+	rbtree_t *tree;
+
+	state_entry_t *head, *tail;
+
+#ifdef HAVE_PTHREAD_H
+	pthread_mutex_t mutex;
+#endif
+};
+
+static fr_state_t global_state;
+
+#define STATE_FREE(_x) if (_x != &global_state) talloc_free(_x)
+
+#ifdef HAVE_PTHREAD_H
+
+#define PTHREAD_MUTEX_LOCK pthread_mutex_lock
+#define PTHREAD_MUTEX_UNLOCK pthread_mutex_unlock
+
+#else
+/*
+ *	This is easier than ifdef's throughout the code.
+ */
+#define PTHREAD_MUTEX_LOCK(_x)
+#define PTHREAD_MUTEX_UNLOCK(_x)
+
+#endif
+
+/*
+ *	rbtree callback.
+ */
+static int state_entry_cmp(void const *one, void const *two)
+{
+	state_entry_t const *a = one;
+	state_entry_t const *b = two;
+
+	return memcmp(a->state, b->state, sizeof(a->state));
+}
+
+static bool state_entry_link(fr_state_t *state, state_entry_t *entry)
+{
+	if (!rbtree_insert(state->tree, entry)) {
+		return false;
+	}
+
+	/*
+	 *	Link it to the end of the list, which is implicitely
+	 *	ordered by cleanup time.
+	 */
+	if (!state->head) {
+		entry->prev = entry->next = NULL;
+		state->head = state->tail = entry;
+	} else {
+		rad_assert(state->tail != NULL);
+
+		entry->prev = state->tail;
+		state->tail->next = entry;
+
+		entry->next = NULL;
+		state->tail = entry;
+	}
+
+	return true;
+}
+
+static void state_entry_unlink(fr_state_t *state, state_entry_t *entry)
+{
+	state_entry_t *prev, *next;
+
+	prev = entry->prev;
+	next = entry->next;
+
+	if (prev) {
+		rad_assert(state->head != entry);
+		prev->next = next;
+	} else if (state->head) {
+		rad_assert(state->head == entry);
+		state->head = next;
+	}
+
+	if (next) {
+		rad_assert(state->tail != entry);
+		next->prev = prev;
+	} else if (state->tail) {
+		rad_assert(state->tail == entry);
+		state->tail = prev;
+	}
+
+	rbtree_deletebydata(state->tree, entry);
+}
+
+/*
+ *	When an entry is free'd, it's removed from the linked list of
+ *	cleanup timers.
+ */
+static void state_entry_free(fr_state_t *state, state_entry_t *entry)
+{
+	/*
+	 *	If we're deleting the whole tree, don't bother doing
+	 *	all of the fixups.
+	 */
+	if (!state || !state->tree) return;
+
+	state_entry_unlink(state, entry);
+
+	if (entry->opaque) {
+		entry->free_opaque(entry->opaque);
+	}
+
+#ifdef WITH_VERIFY_PTR
+	(void) talloc_get_type_abort(entry, state_entry_t);
+#endif
+	if (entry->ctx) talloc_free(entry->ctx);
+
+	talloc_free(entry);
+}
+
+fr_state_t *fr_state_init(TALLOC_CTX *ctx)
+{
+	fr_state_t *state;
+
+	if (!ctx) {
+		state = &global_state;
+		if (state->tree) return state;
+	} else {
+		state = talloc_zero(ctx, fr_state_t);
+		if (!state) return 0;
+	}
+
+#ifdef HAVE_PTHREAD_H
+	if (pthread_mutex_init(&state->mutex, NULL) != 0) {
+		STATE_FREE(state);
+		return NULL;
+	}
+#endif
+
+	state->tree = rbtree_create(NULL, state_entry_cmp, NULL, 0);
+	if (!state->tree) {
+		STATE_FREE(state);
+		return NULL;
+	}
+
+	return state;
+}
+
+void fr_state_delete(fr_state_t *state)
+{
+	rbtree_t *my_tree;
+
+	if (!state) return;
+
+	PTHREAD_MUTEX_LOCK(&state->mutex);
+
+	/*
+	 *	Tell the talloc callback to NOT delete the entry from
+	 *	the tree.  We're deleting the entire tree.
+	 */
+	my_tree = state->tree;
+	state->tree = NULL;
+
+	rbtree_free(my_tree);
+	PTHREAD_MUTEX_UNLOCK(&state->mutex);
+
+	STATE_FREE(state);
+}
+
+/*
+ *	Create a fake request, based on what we know about the
+ *	session that has expired, and inject it into the server to
+ *	allow final logging or cleaning up.
+ */
+static REQUEST *fr_state_cleanup_request(state_entry_t *entry)
+{
+	REQUEST		*request;
+	RADIUS_PACKET	*packet = NULL;
+	RADIUS_PACKET	*reply_packet = NULL;
+	VALUE_PAIR	*vp;
+
+	/*
+	 *	Allocate a new fake request with enough to keep
+	 *	the rest of the server happy.
+	 */
+	request = request_alloc(NULL);
+	if (unlikely(!request)) return NULL;
+
+	packet = rad_alloc(request, false);
+	if (unlikely(!packet)) {
+	error:
+		TALLOC_FREE(reply_packet);
+		TALLOC_FREE(packet);
+		TALLOC_FREE(request);
+		return NULL;
+	}
+
+	reply_packet = rad_alloc(request, false);
+	if (unlikely(!reply_packet)) goto error;
+
+	/*
+	 *	Move the server from the state entry over to the
+	 *	request. Clearing it in the state means this
+	 *	function will never be called again.
+	 */
+	request->server = talloc_steal(request, entry->server);
+	entry->server = NULL;
+
+	/*
+	 *	Build the fake request with the limited
+	 *	information we have from the state.
+	 */
+	request->packet = packet;
+	request->reply = reply_packet;
+	request->number = entry->request_number;
+	request->client = entry->request_client;
+	request->root = entry->request_root;
+	request->handle = rad_postauth;
+
+	/*
+	 *	Move session-state VPS over, after first freeing the
+	 *	separately-parented state_ctx that was allocated along with the
+	 *	fake request.
+	 */
+	talloc_free(request->state_ctx);
+	request->state_ctx = entry->ctx;
+	request->state = entry->vps;
+
+	entry->ctx = NULL;
+	entry->vps = NULL;
+
+	/*
+	 *	Set correct Post-Auth-Type section
+	 */
+	fr_pair_delete_by_num(&request->config, PW_POST_AUTH_TYPE, 0, TAG_ANY);
+	vp = pair_make_config("Post-Auth-Type", "Client-Lost", T_OP_SET);
+	if (unlikely(!vp)) goto error;
+
+	VERIFY_REQUEST(request);
+	return request;
+}
+
+/*
+ *	Check state for old entries that need to be cleaned up. If
+ *	they are old enough then move them from the global state
+ *	list to a list of entries to clean up (outside the mutex).
+ *	Called with the mutex held.
+ */
+static state_entry_t *fr_state_cleanup_find(fr_state_t *state)
+{
+	time_t now = time(NULL);
+	state_entry_t *entry, *next;
+	state_entry_t *head = NULL, **tail = &head;
+
+	for (entry = state->head; entry != NULL; entry = next) {
+		next = entry->next;
+
+		/*
+		 *	Unused.  We can delete it, even if now isn't
+		 *	the time to clean it up.
+		 */
+		if (!entry->ctx && !entry->opaque) {
+			state_entry_free(state, entry);
+			continue;
+		}
+
+		/*
+		 *	Not yet time to clean it up.
+		 */
+		if (entry->cleanup > now) {
+			continue;
+		}
+
+		/*
+		 *	We're not running the "client lost" section.
+		 *	Just nuke the entry now.
+		 */
+		if (!main_config.postauth_client_lost) {
+			state_entry_free(state, entry);
+			continue;
+		}
+
+		/*
+		 *	Old enough that the request has been removed.
+		 *	We can add it to the cleanup list.
+		 */
+		state_entry_unlink(state, entry);
+		entry->prev = entry->next = NULL;
+		(*tail) = entry;
+		tail = &entry->next;
+	}
+
+	return head;
+}
+
+/*
+ *	Inject all requests in cleanup list for cleanup post-auth
+ */
+static void fr_state_cleanup(state_entry_t *head)
+{
+	state_entry_t *entry, *next;
+
+	if (!head) return;
+
+	for (entry = head; entry != NULL; entry = next) {
+		REQUEST *request;
+
+		next = entry->next;
+
+		request = fr_state_cleanup_request(entry);
+		if (request) {
+			RDEBUG2("No response from client, cleaning up expired state");
+			RDEBUG2("Restoring &session-state");
+
+			/*
+			 *	@todo - print out message
+			 *	saying where the handler was
+			 *	in the process?  i.e. "sent
+			 *	server cert", etc.  This will
+			 *	require updating the EAP code
+			 *	to put a new attribute into
+			 *	the session state list.
+			 */
+
+			rdebug_pair_list(L_DBG_LVL_2, request, request->state, "&session-state:");
+
+			request_inject(request);
+		}
+
+		talloc_free(entry);
+	}
+}
+
+
+/*
+ *	Create a new entry.  Called with the mutex held.
+ */
+static state_entry_t *fr_state_entry_create(fr_state_t *state, REQUEST *request, RADIUS_PACKET *packet, state_entry_t *old)
+{
+	size_t i;
+	uint32_t x;
+	time_t now = time(NULL);
+	VALUE_PAIR *vp;
+	state_entry_t *entry;
+
+	/*
+	 *	Limit the size of the cache based on how many requests
+	 *	we can handle at the same time.
+	 */
+	if (rbtree_num_elements(state->tree) >= main_config.max_requests * 2) {
+		return NULL;
+	}
+
+	/*
+	 *	Allocate a new one.
+	 */
+	entry = talloc_zero(state->tree, state_entry_t);
+	if (!entry) return NULL;
+
+	/*
+	 *	Limit the lifetime of this entry based on how long the
+	 *	server takes to process a request.  Doing it this way
+	 *	isn't perfect, but it's reasonable, and it's one less
+	 *	thing for an administrator to configure.
+	 */
+	entry->cleanup = now + main_config.max_request_time * 2;
+
+	/*
+	 *	Hacks for EAP, until we convert EAP to using the state API.
+	 *
+	 *	The EAP module creates it's own State attribute, so we
+	 *	want to use that one in preference to one we create.
+	 */
+	vp = fr_pair_find_by_num(packet->vps, PW_STATE, 0, TAG_ANY);
+
+	/*
+	 *	If possible, base the new one off of the old one.
+	 */
+	if (old) {
+		entry->tries = old->tries + 1;
+
+		/*
+		 *	Track State
+		 */
+		if (!vp) {
+			memcpy(entry->state, old->state, sizeof(entry->state));
+
+			entry->state[1] = entry->state[0] ^ entry->tries;
+			entry->state[8] = entry->state[2] ^ ((((uint32_t) HEXIFY(RADIUSD_VERSION)) >> 16) & 0xff);
+			entry->state[10] = entry->state[2] ^ ((((uint32_t) HEXIFY(RADIUSD_VERSION)) >> 8) & 0xff);
+			entry->state[12] = entry->state[2] ^ (((uint32_t) HEXIFY(RADIUSD_VERSION)) & 0xff);
+		}
+
+		/*
+		 *	The old one isn't used any more, so we can free it.
+		 */
+		if (!old->opaque) state_entry_free(state, old);
+
+	} else if (!vp) {
+		/*
+		 *	16 octets of randomness should be enough to
+		 *	have a globally unique state.
+		 */
+		for (i = 0; i < sizeof(entry->state) / sizeof(x); i++) {
+			x = fr_rand();
+			memcpy(entry->state + (i * 4), &x, sizeof(x));
+		}
+	}
+
+	/*
+	 *	If EAP created a State, use that.  Otherwise, use the
+	 *	one we created above.
+	 */
+	if (vp) {
+		/*
+		 *	Assume our own State first.
+		 */
+		if (vp->vp_length == sizeof(entry->state)) {
+			memcpy(entry->state, vp->vp_octets, sizeof(entry->state));
+
+			/*
+			 *	Too big?  Get the MD5 hash, in order
+			 *	to depend on the entire contents of State.
+			 */
+		} else if (vp->vp_length > sizeof(entry->state)) {
+			fr_md5_calc(entry->state, vp->vp_octets, vp->vp_length);
+
+			/*
+			 *	Too small?  Use the whole thing, and
+			 *	set the rest of entry->state to zero.
+			 */
+		} else {
+			memcpy(entry->state, vp->vp_octets, vp->vp_length);
+			memset(&entry->state[vp->vp_length], 0, sizeof(entry->state) - vp->vp_length);
+		}
+	} else {
+		vp = fr_pair_afrom_num(packet, PW_STATE, 0);
+		fr_pair_value_memcpy(vp, entry->state, sizeof(entry->state));
+		fr_pair_add(&packet->vps, vp);
+	}
+
+	/*	Make unique for different virtual servers handling same request
+	 */
+	if (request->server) {
+		/*
+		 *	Make unique for different virtual servers handling same request
+		 */
+		*((uint32_t *)(&entry->state[4])) ^= fr_hash_string(request->server);
+
+		/*
+		 *	Copy server to state in case it's needed for cleanup
+		 */
+		entry->server = talloc_strdup(entry, request->server);
+		entry->request_number = request->number;
+		entry->request_client = request->client;
+		entry->request_root = request->root;
+	}
+
+	if (!state_entry_link(state, entry)) {
+		talloc_free(entry);
+		return NULL;
+	}
+
+	return entry;
+}
+
+
+/*
+ *	Find the entry, based on the State attribute.
+ */
+static state_entry_t *fr_state_find(fr_state_t *state, const char *server, RADIUS_PACKET *packet)
+{
+	VALUE_PAIR *vp;
+	state_entry_t *entry, my_entry;
+
+	vp = fr_pair_find_by_num(packet->vps, PW_STATE, 0, TAG_ANY);
+	if (!vp) return NULL;
+
+	/*
+	 *	Assume our own State first.
+	 */
+	if (vp->vp_length == sizeof(my_entry.state)) {
+		memcpy(my_entry.state, vp->vp_octets, sizeof(my_entry.state));
+
+		/*
+		 *	Too big?  Get the MD5 hash, in order
+		 *	to depend on the entire contents of State.
+		 */
+	} else if (vp->vp_length > sizeof(my_entry.state)) {
+		fr_md5_calc(my_entry.state, vp->vp_octets, vp->vp_length);
+
+		/*
+		 *	Too small?  Use the whole thing, and
+		 *	set the rest of my_entry.state to zero.
+		 */
+	} else {
+		memcpy(my_entry.state, vp->vp_octets, vp->vp_length);
+		memset(&my_entry.state[vp->vp_length], 0, sizeof(my_entry.state) - vp->vp_length);
+	}
+
+	/*	Make unique for different virtual servers handling same request
+	 */
+	if (server) *((uint32_t *)(&my_entry.state[4])) ^= fr_hash_string(server);
+
+	entry = rbtree_finddata(state->tree, &my_entry);
+
+#ifdef WITH_VERIFY_PTR
+	if (entry)  (void) talloc_get_type_abort(entry, state_entry_t);
+#endif
+
+	return entry;
+}
+
+/*
+ *	Called when sending Access-Accept or Access-Reject, so
+ *	that all State is discarded.
+ */
+void fr_state_discard(REQUEST *request, RADIUS_PACKET *original)
+{
+	state_entry_t *entry;
+	fr_state_t *state = &global_state;
+
+	fr_pair_list_free(&request->state);
+	request->state = NULL;
+
+	PTHREAD_MUTEX_LOCK(&state->mutex);
+	entry = fr_state_find(state, request->server, original);
+	if (entry) state_entry_free(state, entry);
+	PTHREAD_MUTEX_UNLOCK(&state->mutex);
+}
+
+/*
+ *	Get the VPS from the state.
+ */
+void fr_state_get_vps(REQUEST *request, RADIUS_PACKET *packet)
+{
+	state_entry_t *entry;
+	fr_state_t *state = &global_state;
+	TALLOC_CTX *old_ctx = NULL;
+
+	/*
+	 *	No State, don't do anything.
+	 */
+	if (!fr_pair_find_by_num(request->packet->vps, PW_STATE, 0, TAG_ANY)) {
+		RDEBUG3("session-state: No State attribute");
+		return;
+	}
+
+	rad_assert(request->state == NULL);
+
+	PTHREAD_MUTEX_LOCK(&state->mutex);
+	entry = fr_state_find(state, request->server, packet);
+
+	/*
+	 *	This has to be done in a mutex lock, because talloc
+	 *	isn't thread-safe.
+	 */
+	if (entry) {
+		RDEBUG2("Restoring &session-state");
+
+		if (request->state_ctx) old_ctx = request->state_ctx;
+
+		request->state_ctx = entry->ctx;
+		request->state = entry->vps;
+
+		entry->ctx = NULL;
+		entry->vps = NULL;
+
+		rdebug_pair_list(L_DBG_LVL_2, request, request->state, "&session-state:");
+
+	} else {
+		RDEBUG2("session-state: No cached attributes");
+	}
+
+	PTHREAD_MUTEX_UNLOCK(&state->mutex);
+
+	/*
+	 *	Free this outside of the mutex for less contention.
+	 */
+	if (old_ctx) talloc_free(old_ctx);
+
+	VERIFY_REQUEST(request);
+	return;
+}
+
+
+/*
+ *	Put request->state into the State attribute.  Put the State
+ *	attribute into the vps list.  Delete the original entry, if it
+ *	exists.
+ */
+bool fr_state_put_vps(REQUEST *request, RADIUS_PACKET *original, RADIUS_PACKET *packet)
+{
+	state_entry_t *entry, *old;
+	fr_state_t *state = &global_state;
+	state_entry_t *cleanup_list;
+
+	if (!request->state) {
+		size_t i;
+		uint32_t x;
+		VALUE_PAIR *vp;
+		uint8_t buffer[16];
+
+		RDEBUG3("session-state: Nothing to cache");
+
+		if (packet->code != PW_CODE_ACCESS_CHALLENGE) return true;
+
+		vp = fr_pair_find_by_num(packet->vps, PW_STATE, 0, TAG_ANY);
+		if (vp) return true;
+
+		/*
+		 *
+		 */
+		for (i = 0; i < sizeof(buffer) / sizeof(x); i++) {
+			x = fr_rand();
+			memcpy(buffer + (i * 4), &x, sizeof(x));
+		}
+
+		vp = fr_pair_afrom_num(packet, PW_STATE, 0);
+		fr_pair_value_memcpy(vp, buffer, sizeof(buffer));
+		fr_pair_add(&packet->vps, vp);
+
+		return true;
+	}
+
+	RDEBUG2("session-state: Saving cached attributes");
+	rdebug_pair_list(L_DBG_LVL_1, request, request->state, NULL);
+
+	PTHREAD_MUTEX_LOCK(&state->mutex);
+
+	cleanup_list = fr_state_cleanup_find(state);
+
+	if (original) {
+		old = fr_state_find(state, request->server, original);
+	} else {
+		old = NULL;
+	}
+
+	/*
+	 *	Create a new entry and add it to the list.
+	 */
+	entry = fr_state_entry_create(state, request, packet, old);
+	if (!entry) {
+		PTHREAD_MUTEX_UNLOCK(&state->mutex);
+		fr_state_cleanup(cleanup_list);
+		return false;
+	}
+
+	rad_assert(entry->ctx == NULL);
+	entry->ctx = request->state_ctx;
+	entry->vps = request->state;
+
+	request->state_ctx = NULL;
+	request->state = NULL;
+
+	PTHREAD_MUTEX_UNLOCK(&state->mutex);
+	fr_state_cleanup(cleanup_list);
+
+	VERIFY_REQUEST(request);
+	return true;
+}