]> git.ipfire.org Git - thirdparty/strongswan.git/commitdiff
child-rekey: Support CHILD_SA rekeying with multiple key exchanges
authorTobias Brunner <tobias@strongswan.org>
Mon, 29 Jun 2020 12:12:05 +0000 (14:12 +0200)
committerTobias Brunner <tobias@strongswan.org>
Wed, 7 Aug 2024 14:20:18 +0000 (16:20 +0200)
src/libcharon/sa/ikev2/tasks/child_create.c
src/libcharon/sa/ikev2/tasks/child_delete.c
src/libcharon/sa/ikev2/tasks/child_rekey.c

index a04b14d55524a4ab187c012064414352d4924914..132c3de469d87b560b8ac81743cb0125a14c4811 100644 (file)
@@ -2196,6 +2196,10 @@ static status_t delete_failed_sa(private_child_create_t *this)
        {
                this->public.task.build = _build_i_delete;
                this->public.task.process = (void*)return_success;
+               /* destroying it here allows the rekey task to differentiate between
+                * this and the multi-KE case */
+               this->child_sa->destroy(this->child_sa);
+               this->child_sa = NULL;
                return NEED_MORE;
        }
        return SUCCESS;
index 2e2668bbe20b46e2390b80fad9d6c92609ec0173..eff0e6cc601182aede6846c15b52646b7f318bdc 100644 (file)
@@ -187,11 +187,6 @@ static void install_outbound(private_child_delete_t *this,
                DBG1(DBG_IKE, "CHILD_SA not found after rekeying");
                return;
        }
-       if (this->initiator && is_redundant(this, child_sa))
-       {       /* if we won the rekey collision we don't want to install the
-                * redundant SA created by the peer */
-               return;
-       }
 
        status = child_sa->install_outbound(child_sa);
        if (status != SUCCESS)
index 5883a5ef583b59c6365ef1f59f25a05e9b9f3493..6ffeb52c504d97e691cca2d520e1183b5aa6fdc6 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2009-2018 Tobias Brunner
+ * Copyright (C) 2009-2023 Tobias Brunner
  * Copyright (C) 2005-2007 Martin Willi
  * Copyright (C) 2005 Jan Hutter
  *
@@ -84,13 +84,32 @@ struct private_child_rekey_t {
        task_t *collision;
 
        /**
-        * Indicate that peer destroyed the redundant child from collision.
-        * This happens if a peer's delete notification for the redundant
-        * child gets processed before the rekey job. If so, we must not
-        * touch the child created in the collision since it points to
-        * memory already freed.
+        * State flags
         */
-       bool other_child_destroyed;
+       enum {
+
+               /**
+                * Set if we use multiple key exchanges and already processed the
+                * CREATE_CHILD_SA response and started sending IKE_FOLLOWUP_KEs.
+                */
+               CHILD_REKEY_FOLLOWUP_KE = (1<<0),
+
+               /**
+                * Set if we adopted a completed passive task, otherwise (i.e. for
+                * multi-KE rekeyings) we just reference it.
+                */
+               CHILD_REKEY_ADOPTED_PASSIVE = (1<<1),
+
+               /**
+                * Indicate that the peer destroyed the redundant child from a
+                * collision. This happens if a peer's delete notification for the
+                * redundant child gets processed before the active rekey job is
+                * complete. If so, we must not touch the child created in the collision
+                * since it points to memory already freed.
+                */
+               CHILD_REKEY_OTHER_DESTROYED = (1<<2),
+
+       } flags;
 };
 
 /**
@@ -169,8 +188,6 @@ METHOD(task_t, build_i, status_t,
        private_child_rekey_t *this, message_t *message)
 {
        notify_payload_t *notify;
-       uint32_t reqid;
-       child_cfg_t *config;
 
        this->child_sa = this->ike_sa->get_child_sa(this->ike_sa, this->protocol,
                                                                                                this->spi, TRUE);
@@ -194,15 +211,16 @@ METHOD(task_t, build_i, status_t,
                message->set_exchange_type(message, EXCHANGE_TYPE_UNDEFINED);
                return SUCCESS;
        }
-       config = this->child_sa->get_config(this->child_sa);
-
 
        /* our CHILD_CREATE task does the hard work for us */
        if (!this->child_create)
        {
+               child_cfg_t *config;
                proposal_t *proposal;
                uint16_t ke_method;
+               uint32_t reqid;
 
+               config = this->child_sa->get_config(this->child_sa);
                this->child_create = child_create_create(this->ike_sa,
                                                                        config->get_ref(config), TRUE, NULL, NULL);
 
@@ -212,21 +230,21 @@ METHOD(task_t, build_i, status_t,
                {       /* reuse the KE method negotiated previously */
                        this->child_create->use_ke_method(this->child_create, ke_method);
                }
-       }
-       reqid = this->child_sa->get_reqid_ref(this->child_sa);
-       if (reqid)
-       {
-               this->child_create->use_reqid(this->child_create, reqid);
-               charon->kernel->release_reqid(charon->kernel, reqid);
-       }
-       this->child_create->use_marks(this->child_create,
+               reqid = this->child_sa->get_reqid_ref(this->child_sa);
+               if (reqid)
+               {
+                       this->child_create->use_reqid(this->child_create, reqid);
+                       charon->kernel->release_reqid(charon->kernel, reqid);
+               }
+               this->child_create->use_marks(this->child_create,
                                                this->child_sa->get_mark(this->child_sa, TRUE).value,
                                                this->child_sa->get_mark(this->child_sa, FALSE).value);
-       this->child_create->use_if_ids(this->child_create,
+               this->child_create->use_if_ids(this->child_create,
                                                this->child_sa->get_if_id(this->child_sa, TRUE),
                                                this->child_sa->get_if_id(this->child_sa, FALSE));
-       this->child_create->use_label(this->child_create,
+               this->child_create->use_label(this->child_create,
                                                this->child_sa->get_label(this->child_sa));
+       }
 
        if (this->child_create->task.build(&this->child_create->task,
                                                                           message) != NEED_MORE)
@@ -259,14 +277,48 @@ METHOD(task_t, process_r, status_t,
        return NEED_MORE;
 }
 
+/**
+ * Check if we are actively rekeying and, optionally, if we already sent an
+ * IKE_FOLLOWUP_KE message.
+ */
+static bool actively_rekeying(private_child_rekey_t *this, bool *followup_sent)
+{
+       enumerator_t *enumerator;
+       task_t *task;
+       bool found = FALSE;
+
+       enumerator = this->ike_sa->create_task_enumerator(this->ike_sa,
+                                                                                                         TASK_QUEUE_ACTIVE);
+       while (enumerator->enumerate(enumerator, (void**)&task))
+       {
+               if (task->get_type(task) == TASK_CHILD_REKEY)
+               {
+                       private_child_rekey_t *rekey = (private_child_rekey_t*)task;
+
+                       if (this->child_sa == rekey->child_sa)
+                       {
+                               if (followup_sent)
+                               {
+                                       *followup_sent = rekey->flags & CHILD_REKEY_FOLLOWUP_KE;
+                               }
+                               found = TRUE;
+                       }
+                       break;
+               }
+       }
+       enumerator->destroy(enumerator);
+       return found;
+}
+
 METHOD(task_t, build_r, status_t,
        private_child_rekey_t *this, message_t *message)
 {
        notify_payload_t *notify;
        child_cfg_t *config;
-       uint32_t reqid;
-       child_sa_state_t state;
        child_sa_t *child_sa;
+       child_sa_state_t state = CHILD_INSTALLED;
+       uint32_t reqid;
+       bool followup_sent;
 
        if (!this->child_sa)
        {
@@ -284,118 +336,195 @@ METHOD(task_t, build_r, status_t,
                message->add_notify(message, TRUE, TEMPORARY_FAILURE, chunk_empty);
                return SUCCESS;
        }
-
-       /* let the CHILD_CREATE task build the response */
-       reqid = this->child_sa->get_reqid_ref(this->child_sa);
-       if (reqid)
+       if (actively_rekeying(this, &followup_sent) && followup_sent)
        {
-               this->child_create->use_reqid(this->child_create, reqid);
-               charon->kernel->release_reqid(charon->kernel, reqid);
+               DBG1(DBG_IKE, "peer initiated rekeying, but we did too and already "
+                        "sent IKE_FOLLOWUP_KE");
+               message->add_notify(message, TRUE, TEMPORARY_FAILURE, chunk_empty);
+               return SUCCESS;
        }
-       this->child_create->use_marks(this->child_create,
+
+       if (message->get_exchange_type(message) == CREATE_CHILD_SA)
+       {
+               reqid = this->child_sa->get_reqid_ref(this->child_sa);
+               if (reqid)
+               {
+                       this->child_create->use_reqid(this->child_create, reqid);
+                       charon->kernel->release_reqid(charon->kernel, reqid);
+               }
+               this->child_create->use_marks(this->child_create,
                                                this->child_sa->get_mark(this->child_sa, TRUE).value,
                                                this->child_sa->get_mark(this->child_sa, FALSE).value);
-       this->child_create->use_if_ids(this->child_create,
+               this->child_create->use_if_ids(this->child_create,
                                                this->child_sa->get_if_id(this->child_sa, TRUE),
                                                this->child_sa->get_if_id(this->child_sa, FALSE));
-       this->child_create->use_label(this->child_create,
+               this->child_create->use_label(this->child_create,
                                                this->child_sa->get_label(this->child_sa));
-       config = this->child_sa->get_config(this->child_sa);
-       this->child_create->set_config(this->child_create, config->get_ref(config));
-       this->child_create->task.build(&this->child_create->task, message);
+               config = this->child_sa->get_config(this->child_sa);
+               this->child_create->set_config(this->child_create,
+                                                                          config->get_ref(config));
+               state = this->child_sa->get_state(this->child_sa);
+               this->child_sa->set_state(this->child_sa, CHILD_REKEYING);
+       }
 
-       state = this->child_sa->get_state(this->child_sa);
-       this->child_sa->set_state(this->child_sa, CHILD_REKEYING);
+       if (this->child_create->task.build(&this->child_create->task,
+                                                                          message) == NEED_MORE)
+       {
+               /* additional key exchanges */
+               this->flags |= CHILD_REKEY_FOLLOWUP_KE;
+               return NEED_MORE;
+       }
 
-       if (message->get_payload(message, PLV2_SECURITY_ASSOCIATION) == NULL)
+       child_sa = this->child_create->get_child(this->child_create);
+       if (child_sa && child_sa->get_state(child_sa) == CHILD_INSTALLED)
+       {
+               this->child_sa->set_state(this->child_sa, CHILD_REKEYED);
+               this->child_sa->set_rekey_spi(this->child_sa,
+                                                                         child_sa->get_spi(child_sa, FALSE));
+
+               /* FIXME: this might trigger twice if there was a collision */
+               charon->bus->child_rekey(charon->bus, this->child_sa, child_sa);
+       }
+       else if (this->child_sa->get_state(this->child_sa) == CHILD_REKEYING)
        {       /* rekeying failed, reuse old child */
                this->child_sa->set_state(this->child_sa, state);
-               return SUCCESS;
        }
+       return SUCCESS;
+}
 
-       child_sa = this->child_create->get_child(this->child_create);
-       this->child_sa->set_state(this->child_sa, CHILD_REKEYED);
-       this->child_sa->set_rekey_spi(this->child_sa,
-                                                                 child_sa->get_spi(child_sa, FALSE));
+/**
+ * Remove the passive rekey task that's waiting for IKE_FOLLOWUP_KE requests
+ * that will never come.
+ */
+static void remove_passive_rekey_task(private_child_rekey_t *this)
+{
+       enumerator_t *enumerator;
+       task_t *task;
 
-       /* invoke rekey hook */
-       charon->bus->child_rekey(charon->bus, this->child_sa,
-                                                        this->child_create->get_child(this->child_create));
-       return SUCCESS;
+       enumerator = this->ike_sa->create_task_enumerator(this->ike_sa,
+                                                                                                         TASK_QUEUE_PASSIVE);
+       while (enumerator->enumerate(enumerator, &task))
+       {
+               if (task->get_type(task) == TASK_CHILD_REKEY)
+               {
+                       this->ike_sa->remove_task(this->ike_sa, enumerator);
+                       task->destroy(task);
+                       break;
+               }
+       }
+       enumerator->destroy(enumerator);
 }
 
 /**
  * Handle a rekey collision
  */
 static child_sa_t *handle_collision(private_child_rekey_t *this,
-                                                                       child_sa_t **to_install)
+                                                                       child_sa_t **to_install, bool multi_ke)
 {
-       child_sa_t *to_delete;
+       private_child_rekey_t *other = (private_child_rekey_t*)this->collision;
+       chunk_t this_nonce, other_nonce;
+       child_sa_t *to_delete, *child_sa;
+
+       if (this->collision->get_type(this->collision) == TASK_CHILD_DELETE)
+       {       /* CHILD_DELETE, which we only adopt if it is for the CHILD_SA we are
+                * ourselves rekeying */
+               to_delete = this->child_create->get_child(this->child_create);
+               if (multi_ke)
+               {
+                       DBG1(DBG_IKE, "CHILD_SA rekey/delete collision, abort incomplete "
+                                "multi-KE rekeying");
+               }
+               else
+               {
+                       DBG1(DBG_IKE, "CHILD_SA rekey/delete collision, deleting redundant "
+                                "child %s{%d}", to_delete->get_name(to_delete),
+                                to_delete->get_unique_id(to_delete));
+               }
+               return to_delete;
+       }
+
+       this_nonce = this->child_create->get_lower_nonce(this->child_create);
+       other_nonce = other->child_create->get_lower_nonce(other->child_create);
 
-       if (this->collision->get_type(this->collision) == TASK_CHILD_REKEY)
+       /* the SA with the lowest nonce should be deleted (if already complete),
+        * check if we or the peer created it */
+       if (memcmp(this_nonce.ptr, other_nonce.ptr,
+                          min(this_nonce.len, other_nonce.len)) < 0)
        {
-               chunk_t this_nonce, other_nonce;
-               private_child_rekey_t *other = (private_child_rekey_t*)this->collision;
+               to_delete = this->child_create->get_child(this->child_create);
+               if (multi_ke)
+               {
+                       DBG1(DBG_IKE, "CHILD_SA rekey collision lost, abort incomplete "
+                                "multi-KE rekeying");
+               }
+               else
+               {
+                       DBG1(DBG_IKE, "CHILD_SA rekey collision lost, deleting "
+                                "redundant child %s{%d}", to_delete->get_name(to_delete),
+                                to_delete->get_unique_id(to_delete));
+               }
+               return to_delete;
+       }
 
-               this_nonce = this->child_create->get_lower_nonce(this->child_create);
-               other_nonce = other->child_create->get_lower_nonce(other->child_create);
+       *to_install = this->child_create->get_child(this->child_create);
+       to_delete = this->child_sa;
 
-               /* 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)
+       /* the passive rekeying is complete only if it was single-KE.  otherwise,
+        * the peer would either have stopped before sending IKE_FOLLOWUP_KE when
+        * it noticed it lost, or it responded with TEMPORARY_FAILURE to our
+        * CREATE_CHILD_SA request if it already started sending them. */
+       if (this->flags & CHILD_REKEY_ADOPTED_PASSIVE)
+       {
+               /* we don't want to install the peer's redundant outbound SA */
+               this->child_sa->set_rekey_spi(this->child_sa, 0);
+               /* don't touch child other created if it has already been deleted */
+               if (!(this->flags & CHILD_REKEY_OTHER_DESTROYED))
                {
-                       child_sa_t *child_sa;
-
-                       *to_install = this->child_create->get_child(this->child_create);
-                       to_delete = this->child_sa;
-                       DBG1(DBG_IKE, "CHILD_SA rekey collision won, deleting old child "
-                                "%s{%d}", to_delete->get_name(to_delete),
-                                to_delete->get_unique_id(to_delete));
-                       /* don't touch child other created, it has already been deleted */
-                       if (!this->other_child_destroyed)
+                       /* disable close action and updown event for redundant child the
+                        * other is expected to delete */
+                       child_sa = other->child_create->get_child(other->child_create);
+                       if (child_sa)
                        {
-                               /* disable close action and updown event for redundant child */
-                               child_sa = other->child_create->get_child(other->child_create);
-                               if (child_sa)
+                               child_sa->set_close_action(child_sa, ACTION_NONE);
+                               if (child_sa->get_state(child_sa) != CHILD_REKEYED)
                                {
-                                       child_sa->set_close_action(child_sa, ACTION_NONE);
-                                       if (child_sa->get_state(child_sa) != CHILD_REKEYED)
-                                       {
-                                               child_sa->set_state(child_sa, CHILD_REKEYED);
-                                       }
+                                       child_sa->set_state(child_sa, CHILD_REKEYED);
                                }
                        }
                }
+               if (multi_ke)
+               {
+                       DBG1(DBG_IKE, "CHILD_SA rekey collision won, continue with "
+                                "multi-KE rekeying");
+                       /* change the state back, we are not done rekeying yet */
+                       this->child_sa->set_state(this->child_sa, CHILD_REKEYING);
+               }
                else
                {
-                       to_delete = this->child_create->get_child(this->child_create);
-                       DBG1(DBG_IKE, "CHILD_SA rekey collision lost, deleting redundant "
-                                "child %s{%d}", to_delete->get_name(to_delete),
+                       DBG1(DBG_IKE, "CHILD_SA rekey collision won, deleting old child "
+                                "%s{%d}", to_delete->get_name(to_delete),
                                 to_delete->get_unique_id(to_delete));
                }
+               this->collision->destroy(this->collision);
        }
        else
-       {       /* CHILD_DELETE */
-               child_delete_t *del = (child_delete_t*)this->collision;
-
-               /* we didn't had a chance to compare the nonces, so we delete
-                * the CHILD_SA the other is not deleting. */
-               if (del->get_child(del) != this->child_sa)
+       {
+               /* the peer will not continue with its multi-KE rekeying, so we must
+                * remove the passive task that's waiting for IKE_FOLLOWUP_KEs */
+               if (multi_ke)
                {
-                       to_delete = this->child_sa;
-                       DBG1(DBG_IKE, "CHILD_SA rekey/delete collision, deleting old child "
-                                "%s{%d}", to_delete->get_name(to_delete),
-                                to_delete->get_unique_id(to_delete));
+                       DBG1(DBG_IKE, "CHILD_SA rekey collision won, continue with "
+                                "multi-KE rekeying and remove passive %N task",
+                                task_type_names, TASK_CHILD_REKEY);
                }
                else
                {
-                       to_delete = this->child_create->get_child(this->child_create);
-                       DBG1(DBG_IKE, "CHILD_SA rekey/delete collision, deleting redundant "
-                                "child %s{%d}", to_delete->get_name(to_delete),
-                                to_delete->get_unique_id(to_delete));
+                       DBG1(DBG_IKE, "CHILD_SA rekey collision won, remove passive %N "
+                                "task", task_type_names, TASK_CHILD_REKEY);
                }
+               remove_passive_rekey_task(this);
        }
+       this->collision = NULL;
        return to_delete;
 }
 
@@ -404,7 +533,7 @@ METHOD(task_t, process_i, status_t,
 {
        protocol_id_t protocol;
        uint32_t spi;
-       child_sa_t *to_delete, *to_install = NULL;
+       child_sa_t *child_sa, *to_delete = NULL, *to_install = NULL;
 
        if (message->get_notify(message, NO_ADDITIONAL_SAS))
        {
@@ -459,25 +588,43 @@ METHOD(task_t, process_i, status_t,
        if (this->child_create->task.process(&this->child_create->task,
                                                                                 message) == NEED_MORE)
        {
-               /* bad DH group while rekeying, retry, or failure requiring deletion */
-               return NEED_MORE;
+               if (message->get_notify(message, INVALID_KE_PAYLOAD) ||
+                       !this->child_create->get_child(this->child_create))
+               {       /* bad key exchange mechanism, retry, or failure requiring delete */
+                       return NEED_MORE;
+               }
+               /* multiple key exchanges */
+               this->flags |= CHILD_REKEY_FOLLOWUP_KE;
+               /* there will only be a collision while we process a CREATE_CHILD_SA
+                * response, later we just respond with TEMPORARY_FAILURE and ignore
+                * the passive task - if we lost, the returned SA is the one we created
+                * in this task, since it's not complete yet, we abort the task */
+               if (this->collision)
+               {
+                       to_delete = handle_collision(this, &to_install, TRUE);
+               }
+               return (to_delete && to_delete != this->child_sa) ? SUCCESS : NEED_MORE;
        }
-       if (message->get_payload(message, PLV2_SECURITY_ASSOCIATION) == NULL)
+
+       child_sa = this->child_create->get_child(this->child_create);
+       if (!child_sa || child_sa->get_state(child_sa) != CHILD_INSTALLED)
        {
                /* establishing new child failed, reuse old and try again. but not when
-                * we received a delete in the meantime */
+                * we received a delete in the meantime or passively rekeyed the SA */
                if (!this->collision ||
-                        this->collision->get_type(this->collision) != TASK_CHILD_DELETE)
+                       (this->collision->get_type(this->collision) != TASK_CHILD_DELETE &&
+                        !(this->flags & CHILD_REKEY_ADOPTED_PASSIVE)))
                {
                        schedule_delayed_rekey(this);
                }
                return SUCCESS;
        }
 
-       /* check for rekey collisions */
+       /* there won't be a collision if this task is for a multi-KE rekeying, as a
+        * collision during CREATE_CHILD_SA was cleaned up above */
        if (this->collision)
        {
-               to_delete = handle_collision(this, &to_install);
+               to_delete = handle_collision(this, &to_install, FALSE);
        }
        else
        {
@@ -571,18 +718,25 @@ METHOD(child_rekey_t, collide, bool,
                }
                /* ignore passive tasks that did not successfully create a CHILD_SA */
                other_child = rekey->child_create->get_child(rekey->child_create);
-               if (!other_child ||
-                        other_child->get_state(other_child) != CHILD_INSTALLED)
+               if (!other_child)
                {
                        return FALSE;
                }
+               if (other_child->get_state(other_child) != CHILD_INSTALLED)
+               {
+                       DBG1(DBG_IKE, "colliding passive rekeying is not yet complete",
+                                task_type_names, TASK_CHILD_REKEY);
+                       /* we do reference the task to check its state later */
+                       this->collision = other;
+                       return FALSE;
+               }
        }
        else if (other->get_type(other) == TASK_CHILD_DELETE)
        {
                child_delete_t *del = (child_delete_t*)other;
                if (is_redundant(this, del->get_child(del)))
                {
-                       this->other_child_destroyed = TRUE;
+                       this->flags |= CHILD_REKEY_OTHER_DESTROYED;
                        return FALSE;
                }
                if (del->get_child(del) != this->child_sa)
@@ -596,9 +750,15 @@ METHOD(child_rekey_t, collide, bool,
                /* shouldn't happen */
                return FALSE;
        }
+
        DBG1(DBG_IKE, "detected %N collision with %N", task_type_names,
                 TASK_CHILD_REKEY, task_type_names, other->get_type(other));
-       DESTROY_IF(this->collision);
+
+       if (this->flags & CHILD_REKEY_ADOPTED_PASSIVE)
+       {
+               DESTROY_IF(this->collision);
+       }
+       this->flags |= CHILD_REKEY_ADOPTED_PASSIVE;
        this->collision = other;
        return TRUE;
 }
@@ -615,7 +775,10 @@ METHOD(task_t, migrate, void,
        {
                this->child_create->task.migrate(&this->child_create->task, ike_sa);
        }
-       DESTROY_IF(this->collision);
+       if (this->flags & CHILD_REKEY_ADOPTED_PASSIVE)
+       {
+               DESTROY_IF(this->collision);
+       }
 
        this->ike_sa = ike_sa;
        this->collision = NULL;
@@ -632,7 +795,10 @@ METHOD(task_t, destroy, void,
        {
                this->child_delete->task.destroy(&this->child_delete->task);
        }
-       DESTROY_IF(this->collision);
+       if (this->flags & CHILD_REKEY_ADOPTED_PASSIVE)
+       {
+               DESTROY_IF(this->collision);
+       }
        chunk_free(&this->spi_data);
        free(this);
 }