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ike-auth: Calculate and collect IntAuth for IKE_INTERMEDIATE exchanges

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The message ID of the first IKE_AUTH exchange is a safe-guard against
potential truncation attacks if IKE_INTERMEDIATE exchanges are not used
for multiple key exchanges but some other future use where the number of
exchanges might not depend on the selected proposal.
This commit is contained in:
Tobias Brunner 2019-08-20 17:07:55 +02:00
parent 1212780b32
commit f6b2e6a21f
1 changed files with 103 additions and 0 deletions
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103
src/libcharon/sa/ikev2/tasks/ike_auth.c
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@ -81,6 +81,21 @@ struct private_ike_auth_t {
*/ */
packet_t *other_packet; packet_t *other_packet;
/**
* IntAuth data from IKE_INTERMEDIATE exchanges: IntAuth_i | IntAuth_r | MID
*/
chunk_t int_auth;
/**
* Pointer for IntAuth_i into int_auth
*/
chunk_t int_auth_i;
/**
* Pointer for IntAuth_r into int_auth
*/
chunk_t int_auth_r;
/** /**
* Reserved bytes of ID payload * Reserved bytes of ID payload
*/ */
@ -193,6 +208,61 @@ static status_t collect_other_init_data(private_ike_auth_t *this,
return NEED_MORE; return NEED_MORE;
} }
/**
* Collect IntAuth data for IKE_INTERMEDIATE exchanges.
*/
static status_t collect_int_auth_data(private_ike_auth_t *this, bool verify,
message_t *message)
{
keymat_v2_t *keymat;
chunk_t int_auth_ap, prev = chunk_empty, int_auth;
if (!message->get_plain(message, &int_auth_ap))
{
return FAILED;
}
if (this->int_auth.len)
{
prev = this->initiator != verify ? this->int_auth_i : this->int_auth_r;
}
keymat = (keymat_v2_t*)this->ike_sa->get_keymat(this->ike_sa);
if (!keymat->get_int_auth(keymat, verify, int_auth_ap, prev, &int_auth))
{
chunk_free(&int_auth_ap);
return FAILED;
}
chunk_free(&int_auth_ap);
if (!this->int_auth.len)
{ /* IntAuth consists of IntAuth_i | IntAuth_r | MID */
this->int_auth = chunk_alloc(int_auth.len * 2 + sizeof(uint32_t));
this->int_auth_i = chunk_create(this->int_auth.ptr, int_auth.len);
memset(this->int_auth.ptr, 0, this->int_auth.len);
prev = this->int_auth_i;
}
else if (!this->int_auth_r.len)
{
this->int_auth_r = chunk_create(this->int_auth.ptr + int_auth.len,
int_auth.len);
prev = this->int_auth_r;
}
memcpy(prev.ptr, int_auth.ptr, int_auth.len);
chunk_free(&int_auth);
return NEED_MORE;
}
/**
* Set the MID in the IntAuth data to that of the first IKE_AUTH message.
*/
static void set_ike_auth_mid(private_ike_auth_t *this, message_t *message)
{
if (this->int_auth.len)
{
htoun32(this->int_auth.ptr + this->int_auth.len - sizeof(uint32_t),
message->get_message_id(message));
}
}
/** /**
* Get and store reserved bytes of id_payload, required for AUTH payload * Get and store reserved bytes of id_payload, required for AUTH payload
*/ */
@ -662,6 +732,8 @@ METHOD(task_t, build_i, status_t,
charon->bus->alert(charon->bus, ALERT_LOCAL_AUTH_FAILED); charon->bus->alert(charon->bus, ALERT_LOCAL_AUTH_FAILED);
return FAILED; return FAILED;
} }
/* set MID in IntAuth data if used */
set_ike_auth_mid(this, message);
} }
if (!this->do_another_auth && !this->my_auth) if (!this->do_another_auth && !this->my_auth)
@ -733,6 +805,10 @@ METHOD(task_t, build_i, status_t,
charon->bus->alert(charon->bus, ALERT_LOCAL_AUTH_FAILED); charon->bus->alert(charon->bus, ALERT_LOCAL_AUTH_FAILED);
return FAILED; return FAILED;
} }
if (this->int_auth.ptr && this->my_auth->set_int_auth)
{
this->my_auth->set_int_auth(this->my_auth, this->int_auth);
}
} }
/* for authentication methods that return NEED_MORE, the PPK will be reset /* for authentication methods that return NEED_MORE, the PPK will be reset
* in process_i() for messages without PPK_ID notify, so we always set it * in process_i() for messages without PPK_ID notify, so we always set it
@ -784,6 +860,8 @@ METHOD(task_t, post_build_i, status_t,
{ {
case IKE_SA_INIT: case IKE_SA_INIT:
return collect_my_init_data(this, message); return collect_my_init_data(this, message);
case IKE_INTERMEDIATE:
return collect_int_auth_data(this, FALSE, message);
default: default:
return NEED_MORE; return NEED_MORE;
} }
@ -800,6 +878,8 @@ METHOD(task_t, process_r, status_t,
{ {
case IKE_SA_INIT: case IKE_SA_INIT:
return collect_other_init_data(this, message); return collect_other_init_data(this, message);
case IKE_INTERMEDIATE:
return collect_int_auth_data(this, TRUE, message);
case IKE_AUTH: case IKE_AUTH:
break; break;
default: default:
@ -841,6 +921,8 @@ METHOD(task_t, process_r, status_t,
{ {
this->initial_contact = TRUE; this->initial_contact = TRUE;
} }
/* set MID in IntAuth data if used */
set_ike_auth_mid(this, message);
this->first_auth = TRUE; this->first_auth = TRUE;
} }
@ -912,6 +994,10 @@ METHOD(task_t, process_r, status_t,
this->authentication_failed = TRUE; this->authentication_failed = TRUE;
return NEED_MORE; return NEED_MORE;
} }
if (this->int_auth.ptr && this->other_auth->set_int_auth)
{
this->other_auth->set_int_auth(this->other_auth, this->int_auth);
}
} }
if (message->get_payload(message, PLV2_AUTH) && if (message->get_payload(message, PLV2_AUTH) &&
is_first_round(this, FALSE)) is_first_round(this, FALSE))
@ -1097,6 +1183,10 @@ METHOD(task_t, build_r, status_t,
{ {
goto local_auth_failed; goto local_auth_failed;
} }
if (this->int_auth.ptr && this->my_auth->set_int_auth)
{
this->my_auth->set_int_auth(this->my_auth, this->int_auth);
}
} }
} }
@ -1219,6 +1309,8 @@ METHOD(task_t, post_build_r, status_t,
{ {
case IKE_SA_INIT: case IKE_SA_INIT:
return collect_my_init_data(this, message); return collect_my_init_data(this, message);
case IKE_INTERMEDIATE:
return collect_int_auth_data(this, FALSE, message);
default: default:
return NEED_MORE; return NEED_MORE;
} }
@ -1299,6 +1391,8 @@ METHOD(task_t, process_i, status_t,
this->ike_sa->enable_extension(this->ike_sa, EXT_MULTIPLE_AUTH); this->ike_sa->enable_extension(this->ike_sa, EXT_MULTIPLE_AUTH);
} }
return collect_other_init_data(this, message); return collect_other_init_data(this, message);
case IKE_INTERMEDIATE:
return collect_int_auth_data(this, TRUE, message);
case IKE_AUTH: case IKE_AUTH:
break; break;
default: default:
@ -1404,6 +1498,11 @@ METHOD(task_t, process_i, status_t,
{ {
goto peer_auth_failed; goto peer_auth_failed;
} }
if (this->int_auth.ptr && this->other_auth->set_int_auth)
{
this->other_auth->set_int_auth(this->other_auth,
this->int_auth);
}
} }
else else
{ {
@ -1558,6 +1657,9 @@ METHOD(task_t, migrate, void,
clear_ppk(this); clear_ppk(this);
chunk_free(&this->my_nonce); chunk_free(&this->my_nonce);
chunk_free(&this->other_nonce); chunk_free(&this->other_nonce);
chunk_free(&this->int_auth);
this->int_auth_i = chunk_empty;
this->int_auth_r = chunk_empty;
DESTROY_IF(this->my_packet); DESTROY_IF(this->my_packet);
DESTROY_IF(this->other_packet); DESTROY_IF(this->other_packet);
DESTROY_IF(this->peer_cfg); DESTROY_IF(this->peer_cfg);
@ -1586,6 +1688,7 @@ METHOD(task_t, destroy, void,
clear_ppk(this); clear_ppk(this);
chunk_free(&this->my_nonce); chunk_free(&this->my_nonce);
chunk_free(&this->other_nonce); chunk_free(&this->other_nonce);
chunk_free(&this->int_auth);
DESTROY_IF(this->my_packet); DESTROY_IF(this->my_packet);
DESTROY_IF(this->other_packet); DESTROY_IF(this->other_packet);
DESTROY_IF(this->my_auth); DESTROY_IF(this->my_auth);