1 files changed, 430 insertions, 0 deletions
diff --git a/src/libcharon/sa/tasks/child_rekey.c b/src/libcharon/sa/tasks/child_rekey.c
new file mode 100644
index 000000000..b5e4e84b4
--- /dev/null
+++ b/src/libcharon/sa/tasks/child_rekey.c
@@ -0,0 +1,430 @@
+/*
+ * Copyright (C) 2005-2007 Martin Willi
+ * Copyright (C) 2005 Jan Hutter
+ * Hochschule fuer Technik Rapperswil
+ *
+ * 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.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * 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.
+ */
+
+#include "child_rekey.h"
+
+#include <daemon.h>
+#include <encoding/payloads/notify_payload.h>
+#include <sa/tasks/child_create.h>
+#include <sa/tasks/child_delete.h>
+#include <processing/jobs/rekey_child_sa_job.h>
+#include <processing/jobs/rekey_ike_sa_job.h>
+
+
+typedef struct private_child_rekey_t private_child_rekey_t;
+
+/**
+ * Private members of a child_rekey_t task.
+ */
+struct private_child_rekey_t {
+
+	/**
+	 * Public methods and task_t interface.
+	 */
+	child_rekey_t public;
+
+	/**
+	 * Assigned IKE_SA.
+	 */
+	ike_sa_t *ike_sa;
+
+	/**
+	 * Are we the initiator?
+	 */
+	bool initiator;
+
+	/**
+	 * Protocol of CHILD_SA to rekey
+	 */
+	protocol_id_t protocol;
+
+	/**
+	 * Inbound SPI of CHILD_SA to rekey
+	 */
+	u_int32_t spi;
+
+	/**
+	 * the CHILD_CREATE task which is reused to simplify rekeying
+	 */
+	child_create_t *child_create;
+
+	/**
+	 * the CHILD_DELETE task to delete rekeyed CHILD_SA
+	 */
+	child_delete_t *child_delete;
+
+	/**
+	 * CHILD_SA which gets rekeyed
+	 */
+	child_sa_t *child_sa;
+
+	/**
+	 * colliding task, may be delete or rekey
+	 */
+	task_t *collision;
+};
+
+/**
+ * Implementation of task_t.build for initiator, after rekeying
+ */
+static status_t build_i_delete(private_child_rekey_t *this, message_t *message)
+{
+	/* update exchange type to INFORMATIONAL for the delete */
+	message->set_exchange_type(message, INFORMATIONAL);
+
+	return this->child_delete->task.build(&this->child_delete->task, message);
+}
+
+/**
+ * Implementation of task_t.process for initiator, after rekeying
+ */
+static status_t process_i_delete(private_child_rekey_t *this, message_t *message)
+{
+	return this->child_delete->task.process(&this->child_delete->task, message);
+}
+
+/**
+ * find a child using the REKEY_SA notify
+ */
+static void find_child(private_child_rekey_t *this, message_t *message)
+{
+	notify_payload_t *notify;
+	protocol_id_t protocol;
+	u_int32_t spi;
+
+	notify = message->get_notify(message, REKEY_SA);
+	if (notify)
+	{
+		protocol = notify->get_protocol_id(notify);
+		spi = notify->get_spi(notify);
+
+		if (protocol == PROTO_ESP || protocol == PROTO_AH)
+		{
+			this->child_sa = this->ike_sa->get_child_sa(this->ike_sa, protocol,
+														spi, FALSE);
+		}
+	}
+}
+
+/**
+ * Implementation of task_t.build for initiator
+ */
+static status_t build_i(private_child_rekey_t *this, message_t *message)
+{
+	notify_payload_t *notify;
+	u_int32_t reqid;
+	child_cfg_t *config;
+
+	this->child_sa = this->ike_sa->get_child_sa(this->ike_sa, this->protocol,
+												this->spi, TRUE);
+	if (!this->child_sa)
+	{	/* check if it is an outbound CHILD_SA */
+		this->child_sa = this->ike_sa->get_child_sa(this->ike_sa, this->protocol,
+													this->spi, FALSE);
+		if (!this->child_sa)
+		{	/* CHILD_SA is gone, unable to rekey. As an empty CREATE_CHILD_SA
+			 * exchange is invalid, we fall back to an INFORMATIONAL exchange.*/
+			message->set_exchange_type(message, INFORMATIONAL);
+			return SUCCESS;
+		}
+		/* we work only with the inbound SPI */
+		this->spi = this->child_sa->get_spi(this->child_sa, TRUE);
+	}
+	config = this->child_sa->get_config(this->child_sa);
+
+	/* we just need the rekey notify ... */
+	notify = notify_payload_create_from_protocol_and_type(this->protocol,
+														  REKEY_SA);
+	notify->set_spi(notify, this->spi);
+	message->add_payload(message, (payload_t*)notify);
+
+	/* ... our CHILD_CREATE task does the hard work for us. */
+	if (!this->child_create)
+	{
+		this->child_create = child_create_create(this->ike_sa, config, TRUE,
+												 NULL, NULL);
+	}
+	reqid = this->child_sa->get_reqid(this->child_sa);
+	this->child_create->use_reqid(this->child_create, reqid);
+	this->child_create->task.build(&this->child_create->task, message);
+
+	this->child_sa->set_state(this->child_sa, CHILD_REKEYING);
+
+	return NEED_MORE;
+}
+
+/**
+ * Implementation of task_t.process for initiator
+ */
+static status_t process_r(private_child_rekey_t *this, message_t *message)
+{
+	/* let the CHILD_CREATE task process the message */
+	this->child_create->task.process(&this->child_create->task, message);
+
+	find_child(this, message);
+
+	return NEED_MORE;
+}
+
+/**
+ * Implementation of task_t.build for responder
+ */
+static status_t build_r(private_child_rekey_t *this, message_t *message)
+{
+	u_int32_t reqid;
+
+	if (this->child_sa == NULL ||
+		this->child_sa->get_state(this->child_sa) == CHILD_DELETING)
+	{
+		DBG1(DBG_IKE, "unable to rekey, CHILD_SA not found");
+		message->add_notify(message, TRUE, NO_PROPOSAL_CHOSEN, chunk_empty);
+		return SUCCESS;
+	}
+
+	/* let the CHILD_CREATE task build the response */
+	reqid = this->child_sa->get_reqid(this->child_sa);
+	this->child_create->use_reqid(this->child_create, reqid);
+	this->child_create->task.build(&this->child_create->task, message);
+
+	if (message->get_payload(message, SECURITY_ASSOCIATION) == NULL)
+	{
+		/* rekeying failed, reuse old child */
+		this->child_sa->set_state(this->child_sa, CHILD_INSTALLED);
+		return SUCCESS;
+	}
+
+	this->child_sa->set_state(this->child_sa, CHILD_REKEYING);
+
+	/* invoke rekey hook */
+	charon->bus->child_rekey(charon->bus, this->child_sa,
+							 this->child_create->get_child(this->child_create));
+	return SUCCESS;
+}
+
+/**
+ * Implementation of task_t.process for initiator
+ */
+static status_t process_i(private_child_rekey_t *this, message_t *message)
+{
+	protocol_id_t protocol;
+	u_int32_t spi;
+	child_sa_t *to_delete;
+
+	if (message->get_notify(message, NO_ADDITIONAL_SAS))
+	{
+		DBG1(DBG_IKE, "peer seems to not support CHILD_SA rekeying, "
+			 "starting reauthentication");
+		this->child_sa->set_state(this->child_sa, CHILD_INSTALLED);
+		charon->processor->queue_job(charon->processor,
+				(job_t*)rekey_ike_sa_job_create(
+							this->ike_sa->get_id(this->ike_sa), TRUE));
+		return SUCCESS;
+	}
+
+	if (this->child_create->task.process(&this->child_create->task,
+										 message) == NEED_MORE)
+	{
+		/* bad DH group while rekeying, try again */
+		this->child_create->task.migrate(&this->child_create->task, this->ike_sa);
+		return NEED_MORE;
+	}
+	if (message->get_payload(message, SECURITY_ASSOCIATION) == NULL)
+	{
+		/* establishing new child failed, reuse old. but not when we
+		 * recieved a delete in the meantime */
+		if (!(this->collision &&
+			  this->collision->get_type(this->collision) == CHILD_DELETE))
+		{
+			job_t *job;
+			u_int32_t retry = RETRY_INTERVAL - (random() % RETRY_JITTER);
+
+			job = (job_t*)rekey_child_sa_job_create(
+								this->child_sa->get_reqid(this->child_sa),
+								this->child_sa->get_protocol(this->child_sa),
+								this->child_sa->get_spi(this->child_sa, TRUE));
+			DBG1(DBG_IKE, "CHILD_SA rekeying failed, "
+								"trying again in %d seconds", retry);
+			this->child_sa->set_state(this->child_sa, CHILD_INSTALLED);
+			charon->scheduler->schedule_job(charon->scheduler, job, retry);
+		}
+		return SUCCESS;
+	}
+
+	to_delete = this->child_sa;
+
+	/* check for rekey collisions */
+	if (this->collision &&
+		this->collision->get_type(this->collision) == CHILD_REKEY)
+	{
+		chunk_t this_nonce, other_nonce;
+		private_child_rekey_t *other = (private_child_rekey_t*)this->collision;
+
+		this_nonce = this->child_create->get_lower_nonce(this->child_create);
+		other_nonce = other->child_create->get_lower_nonce(other->child_create);
+
+		/* if we have the lower nonce, delete rekeyed SA. If not, delete
+		 * the redundant. */
+		if (memcmp(this_nonce.ptr, other_nonce.ptr,
+				   min(this_nonce.len, other_nonce.len)) < 0)
+		{
+			DBG1(DBG_IKE, "CHILD_SA rekey collision won, deleting rekeyed child");
+		}
+		else
+		{
+			DBG1(DBG_IKE, "CHILD_SA rekey collision lost, deleting redundant child");
+			to_delete = this->child_create->get_child(this->child_create);
+			if (to_delete == NULL)
+			{
+				/* ooops, should not happen, fallback */
+				to_delete = this->child_sa;
+			}
+		}
+	}
+
+	if (to_delete != this->child_create->get_child(this->child_create))
+	{	/* invoke rekey hook if rekeying successful */
+		charon->bus->child_rekey(charon->bus, this->child_sa,
+							this->child_create->get_child(this->child_create));
+	}
+
+	spi = to_delete->get_spi(to_delete, TRUE);
+	protocol = to_delete->get_protocol(to_delete);
+
+	/* rekeying done, delete the obsolete CHILD_SA using a subtask */
+	this->child_delete = child_delete_create(this->ike_sa, protocol, spi);
+	this->public.task.build = (status_t(*)(task_t*,message_t*))build_i_delete;
+	this->public.task.process = (status_t(*)(task_t*,message_t*))process_i_delete;
+
+	return NEED_MORE;
+}
+
+/**
+ * Implementation of task_t.get_type
+ */
+static task_type_t get_type(private_child_rekey_t *this)
+{
+	return CHILD_REKEY;
+}
+
+/**
+ * Implementation of child_rekey_t.collide
+ */
+static void collide(private_child_rekey_t *this, task_t *other)
+{
+	/* the task manager only detects exchange collision, but not if
+	 * the collision is for the same child. we check it here. */
+	if (other->get_type(other) == CHILD_REKEY)
+	{
+		private_child_rekey_t *rekey = (private_child_rekey_t*)other;
+		if (rekey == NULL || rekey->child_sa != this->child_sa)
+		{
+			/* not the same child => no collision */
+			other->destroy(other);
+			return;
+		}
+	}
+	else if (other->get_type(other) == CHILD_DELETE)
+	{
+		child_delete_t *del = (child_delete_t*)other;
+		if (del == NULL || del->get_child(del) != this->child_sa)
+		{
+			/* not the same child => no collision */
+			other->destroy(other);
+			return;
+		}
+	}
+	else
+	{
+		/* any other task is not critical for collisisions, ignore */
+		other->destroy(other);
+		return;
+	}
+	DESTROY_IF(this->collision);
+	this->collision = other;
+}
+
+/**
+ * Implementation of task_t.migrate
+ */
+static void migrate(private_child_rekey_t *this, ike_sa_t *ike_sa)
+{
+	if (this->child_create)
+	{
+		this->child_create->task.migrate(&this->child_create->task, ike_sa);
+	}
+	if (this->child_delete)
+	{
+		this->child_delete->task.migrate(&this->child_delete->task, ike_sa);
+	}
+	DESTROY_IF(this->collision);
+
+	this->ike_sa = ike_sa;
+	this->collision = NULL;
+}
+
+/**
+ * Implementation of task_t.destroy
+ */
+static void destroy(private_child_rekey_t *this)
+{
+	if (this->child_create)
+	{
+		this->child_create->task.destroy(&this->child_create->task);
+	}
+	if (this->child_delete)
+	{
+		this->child_delete->task.destroy(&this->child_delete->task);
+	}
+	DESTROY_IF(this->collision);
+	free(this);
+}
+
+/*
+ * Described in header.
+ */
+child_rekey_t *child_rekey_create(ike_sa_t *ike_sa, protocol_id_t protocol,
+								  u_int32_t spi)
+{
+	private_child_rekey_t *this = malloc_thing(private_child_rekey_t);
+
+	this->public.collide = (void (*)(child_rekey_t*,task_t*))collide;
+	this->public.task.get_type = (task_type_t(*)(task_t*))get_type;
+	this->public.task.migrate = (void(*)(task_t*,ike_sa_t*))migrate;
+	this->public.task.destroy = (void(*)(task_t*))destroy;
+	if (protocol != PROTO_NONE)
+	{
+		this->public.task.build = (status_t(*)(task_t*,message_t*))build_i;
+		this->public.task.process = (status_t(*)(task_t*,message_t*))process_i;
+		this->initiator = TRUE;
+		this->child_create = NULL;
+	}
+	else
+	{
+		this->public.task.build = (status_t(*)(task_t*,message_t*))build_r;
+		this->public.task.process = (status_t(*)(task_t*,message_t*))process_r;
+		this->initiator = FALSE;
+		this->child_create = child_create_create(ike_sa, NULL, TRUE, NULL, NULL);
+	}
+
+	this->ike_sa = ike_sa;
+	this->child_sa = NULL;
+	this->protocol = protocol;
+	this->spi = spi;
+	this->collision = NULL;
+	this->child_delete = NULL;
+
+	return &this->public;
+}