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child-rekey: Support CHILD_SA rekeying with multiple key exchanges

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This commit is contained in:
Tobias Brunner 2020-06-29 14:12:05 +02:00 committed by Andreas Steffen
parent ce4a3d6d75
commit e44b7695c9
3 changed files with 287 additions and 122 deletions
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4
src/libcharon/sa/ikev2/tasks/child_create.c
View File

@ -2058,6 +2058,10 @@ 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;

5
src/libcharon/sa/ikev2/tasks/child_delete.c
View File

@ -186,11 +186,6 @@ 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)

400
src/libcharon/sa/ikev2/tasks/child_rekey.c
View File

@ -1,5 +1,5 @@
/*
* Copyright (C) 2009-2018 Tobias Brunner
* Copyright (C) 2009-2020 Tobias Brunner
* Copyright (C) 2005-2007 Martin Willi
* Copyright (C) 2005 Jan Hutter
* HSR Hochschule fuer Technik Rapperswil
@ -78,13 +78,32 @@ 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;
};
/**
@ -158,8 +177,6 @@ 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);
@ -183,15 +200,16 @@ 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 dh_group;
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);
@ -201,15 +219,15 @@ METHOD(task_t, build_i, status_t,
{ /* reuse the DH group negotiated previously */
this->child_create->use_dh_group(this->child_create, dh_group);
}
}
reqid = this->child_sa->get_reqid(this->child_sa);
this->child_create->use_reqid(this->child_create, reqid);
this->child_create->use_marks(this->child_create,
reqid = this->child_sa->get_reqid(this->child_sa);
this->child_create->use_reqid(this->child_create, 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));
}
if (this->child_create->task.build(&this->child_create->task,
message) != NEED_MORE)
@ -242,13 +260,47 @@ 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)
{
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)
{
@ -262,112 +314,189 @@ 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(this->child_sa);
this->child_create->use_reqid(this->child_create, 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_sa->get_if_id(this->child_sa, TRUE),
this->child_sa->get_if_id(this->child_sa, FALSE));
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);
state = this->child_sa->get_state(this->child_sa);
this->child_sa->set_state(this->child_sa, CHILD_REKEYING);
if (message->get_payload(message, PLV2_SECURITY_ASSOCIATION) == NULL)
{ /* rekeying failed, reuse old child */
this->child_sa->set_state(this->child_sa, state);
if (actively_rekeying(this, &followup_sent) && followup_sent)
{
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;
}
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));
if (message->get_exchange_type(message) == CREATE_CHILD_SA)
{
reqid = this->child_sa->get_reqid(this->child_sa);
this->child_create->use_reqid(this->child_create, 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_sa->get_if_id(this->child_sa, TRUE),
this->child_sa->get_if_id(this->child_sa, FALSE));
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);
}
/* invoke rekey hook */
charon->bus->child_rekey(charon->bus, this->child_sa,
this->child_create->get_child(this->child_create));
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;
}
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;
}
/**
* 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;
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_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)
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)
{
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 */
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_state(child_sa, CHILD_REKEYED);
}
}
}
DBG1(DBG_IKE, "CHILD_SA rekey/delete collision, abort incomplete "
"multi-KE 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),
to_delete->get_unique_id(to_delete));
}
}
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)
{
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));
}
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));
}
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);
/* 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)
{
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;
}
*to_install = this->child_create->get_child(this->child_create);
to_delete = this->child_sa;
/* 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))
{
/* 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)
{
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);
}
}
}
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
{
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
{
/* 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)
{
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
{
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;
}
@ -376,7 +505,7 @@ 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))
{
@ -420,25 +549,43 @@ 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
{
@ -480,7 +627,7 @@ METHOD(task_t, process_i, status_t,
charon->bus->child_rekey(charon->bus, this->child_sa,
this->child_create->get_child(this->child_create));
}
if (to_delete == NULL)
if (!to_delete)
{
return SUCCESS;
}
@ -534,18 +681,25 @@ 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)
@ -559,9 +713,15 @@ 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;
}
@ -578,7 +738,10 @@ 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;
@ -595,7 +758,10 @@ 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);
}
free(this);
}