Add support for INVALID_KE_PAYLOAD in CREATE_CHILD_SA

exchange.  In the case of an invalid KE error, retry
CREATE_CHILD_SA exchange with different group instead
of restarting the full IKE handshake.

ok markus@

diff --git a/sbin/iked/config.c b/sbin/iked/config.c
index a77e532..7df23d8 100644 (file)
--- a/sbin/iked/config.c
+++ b/sbin/iked/config.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: config.c,v 1.74 2020/11/29 21:00:43 tobhe Exp $       */
+/*     $OpenBSD: config.c,v 1.75 2021/01/21 16:46:47 tobhe Exp $       */
 
 /*
  * Copyright (c) 2019 Tobias Heider <tobias.heider@stusta.de>
@@ -84,8 +84,7 @@ config_free_kex(struct iked_kex *kex)
        ibuf_release(kex->kex_inonce);
        ibuf_release(kex->kex_rnonce);
 
-       if (kex->kex_dhgroup != NULL)
-               group_free(kex->kex_dhgroup);
+       group_free(kex->kex_dhgroup);
        ibuf_release(kex->kex_dhiexchange);
        ibuf_release(kex->kex_dhrexchange);
 
@@ -140,8 +139,7 @@ config_free_sa(struct iked *env, struct iked_sa *sa)
        ibuf_release(sa->sa_inonce);
        ibuf_release(sa->sa_rnonce);
 
-       if (sa->sa_dhgroup != NULL)
-               group_free(sa->sa_dhgroup);
+       group_free(sa->sa_dhgroup);
        ibuf_release(sa->sa_dhiexchange);
        ibuf_release(sa->sa_dhrexchange);
 
@@ -408,7 +406,7 @@ config_add_transform(struct iked_proposal *prop, unsigned int type,
 }
 
 struct iked_transform *
-config_findtransform(struct iked_proposals *props, uint8_t type,
+config_findtransform_ext(struct iked_proposals *props, uint8_t type, int id,
     unsigned int proto)
 {
        struct iked_proposal    *prop;
@@ -422,6 +420,9 @@ config_findtransform(struct iked_proposals *props, uint8_t type,
                        continue;
                for (i = 0; i < prop->prop_nxforms; i++) {
                        xform = prop->prop_xforms + i;
+                       /* optional lookup of specific transform */
+                       if (id >= 0 && xform->xform_id != id)
+                               continue;
                        if (xform->xform_type == type)
                                return (xform);
                }
@@ -430,6 +431,13 @@ config_findtransform(struct iked_proposals *props, uint8_t type,
        return (NULL);
 }
 
+struct iked_transform *
+config_findtransform(struct iked_proposals *props, uint8_t type,
+    unsigned int proto)
+{
+       return config_findtransform_ext(props, type, -1, proto);
+}
+
 struct iked_user *
 config_new_user(struct iked *env, struct iked_user *new)
 {

diff --git a/sbin/iked/iked.h b/sbin/iked/iked.h
index 242ceef..a8578d8 100644 (file)
--- a/sbin/iked/iked.h
+++ b/sbin/iked/iked.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: iked.h,v 1.179 2020/12/21 22:49:36 tobhe Exp $        */
+/*     $OpenBSD: iked.h,v 1.180 2021/01/21 16:46:47 tobhe Exp $        */
 
 /*
  * Copyright (c) 2019 Tobias Heider <tobias.heider@stusta.de>
@@ -479,7 +479,7 @@ struct iked_sa {
        struct iked_sa                  *sa_previ;      /* matching back pointer */
        struct iked_sa                  *sa_nextr;      /* simultaneous rekey */
        struct iked_sa                  *sa_prevr;      /* matching back pointer */
-       uint64_t                         sa_rekeyspi;   /* peerspi CSA rekey*/
+       uint64_t                         sa_rekeyspi;   /* peerspi CSA rekey */
        struct ibuf                     *sa_simult;     /* simultaneous rekey */
 
        struct iked_ipcomp               sa_ipcompi;    /* IPcomp initator */
@@ -800,6 +800,8 @@ uint64_t
         config_getspi(void);
 struct iked_transform *
         config_findtransform(struct iked_proposals *, uint8_t, unsigned int);
+struct iked_transform *
+        config_findtransform_ext(struct iked_proposals *, uint8_t,int, unsigned int);
 void    config_free_policy(struct iked *, struct iked_policy *);
 struct iked_proposal *
         config_add_proposal(struct iked_proposals *, unsigned int,

diff --git a/sbin/iked/ikev2.c b/sbin/iked/ikev2.c
index 5a2a2c5..2f7b781 100644 (file)
--- a/sbin/iked/ikev2.c
+++ b/sbin/iked/ikev2.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: ikev2.c,v 1.295 2021/01/20 18:44:28 tobhe Exp $       */
+/*     $OpenBSD: ikev2.c,v 1.296 2021/01/21 16:46:47 tobhe Exp $       */
 
 /*
  * Copyright (c) 2019 Tobias Heider <tobias.heider@stusta.de>
@@ -103,7 +103,7 @@ ssize_t      ikev2_handle_delete(struct iked *, struct iked_message *,
            struct ibuf *, struct ikev2_payload **, uint8_t *);
 
 int     ikev2_send_create_child_sa(struct iked *, struct iked_sa *,
-           struct iked_spi *, uint8_t);
+           struct iked_spi *, uint8_t, uint16_t);
 int     ikev2_ikesa_enable(struct iked *, struct iked_sa *, struct iked_sa *);
 void    ikev2_ikesa_delete(struct iked *, struct iked_sa *, int);
 int     ikev2_nonce_cmp(struct ibuf *, struct ibuf *);
@@ -593,6 +593,7 @@ ikev2_recv(struct iked *env, struct iked_message *msg)
 
        initiator = (hdr->ike_flags & IKEV2_FLAG_INITIATOR) ? 0 : 1;
        msg->msg_response = (hdr->ike_flags & IKEV2_FLAG_RESPONSE) ? 1 : 0;
+       msg->msg_exchange = hdr->ike_exchange;
        msg->msg_sa = sa_lookup(env,
            betoh64(hdr->ike_ispi), betoh64(hdr->ike_rspi),
            initiator);
@@ -2952,7 +2953,10 @@ ikev2_handle_notifies(struct iked *env, struct iked_message *msg)
 {
        struct iked_ipcomp      *ic;
        struct iked_sa          *sa;
-       uint16_t                 group;
+       struct iked_spi          rekey;
+       struct group            *group;
+       uint16_t                 groupid;
+       unsigned int             protoid;
 
        if ((sa = msg->msg_sa) == NULL)
                return (-1);
@@ -2980,39 +2984,85 @@ ikev2_handle_notifies(struct iked *env, struct iked_message *msg)
        }
 
        if (msg->msg_flags & IKED_MSG_FLAGS_INVALID_KE) {
-               /* XXX chould also happen for PFS */
-               group = betoh16(msg->msg_group);
-               if (!sa->sa_hdr.sh_initiator) {
-                       log_debug("%s: not an initiator", __func__);
+               groupid = betoh16(msg->msg_group);
+               if (group_getid(groupid) == NULL) {
+                       log_debug("%s: unable to select DH group %u",
+                           __func__, groupid);
                        ikev2_ike_sa_setreason(sa,
-                           "received invalid KE as responder");
+                           "unable to select DH group");
                        sa_state(env, sa, IKEV2_STATE_CLOSED);
                        msg->msg_sa = NULL;
                        return (-1);
                }
-               if (group_getid(group) == NULL) {
-                       log_debug("%s: unable to select DH group %u", __func__,
-                           group);
+               log_debug("%s: responder selected DH group %u", __func__,
+                   groupid);
+               switch (msg->msg_exchange) {
+               case IKEV2_EXCHANGE_IKE_SA_INIT:
+                       protoid = IKEV2_SAPROTO_ESP;
+                       if (!sa->sa_hdr.sh_initiator) {
+                               log_debug("%s: not an initiator", __func__);
+                               ikev2_ike_sa_setreason(sa,
+                                   "received invalid KE as responder");
+                               sa_state(env, sa, IKEV2_STATE_CLOSED);
+                               msg->msg_sa = NULL;
+                               return (-1);
+                       }
+                       if (config_findtransform_ext(&msg->msg_policy->pol_proposals,
+                           IKEV2_XFORMTYPE_DH, groupid, protoid) == NULL) {
+                               log_debug("%s: DH group %u denied by policy",
+                                   __func__, groupid);
+                               ikev2_ike_sa_setreason(sa,
+                                   "unsupported group in INVALID_KE message");
+                               sa_state(env, sa, IKEV2_STATE_CLOSED);
+                               msg->msg_sa = NULL;
+                               return (-1);
+                       }
                        ikev2_ike_sa_setreason(sa,
-                           "unable to select DH group");
+                           "reinitiating with new DH group");
                        sa_state(env, sa, IKEV2_STATE_CLOSED);
                        msg->msg_sa = NULL;
+                       msg->msg_policy->pol_peerdh = groupid;
+                       timer_set(env, &env->sc_inittmr, ikev2_init_ike_sa, NULL);
+                       timer_add(env, &env->sc_inittmr, IKED_INITIATOR_INITIAL);
+                       return (-1);
+               case IKEV2_EXCHANGE_CREATE_CHILD_SA:
+                       if (!(sa->sa_stateflags & IKED_REQ_CHILDSA)) {
+                               log_debug("%s: IKED_REQ_CHILDSA missing",
+                                    __func__);
+                               return (-1);
+                       }
+                       sa->sa_stateflags &= ~IKED_REQ_CHILDSA;
+                       protoid = sa->sa_rekeyspi ?
+                           IKEV2_SAPROTO_ESP : IKEV2_SAPROTO_IKE;
+                       if (config_findtransform_ext(&msg->msg_policy->pol_proposals,
+                           IKEV2_XFORMTYPE_DH, groupid, protoid) == NULL) {
+                               log_debug("%s: DH group %u denied by policy",
+                                   __func__, groupid);
+                               ikev2_ike_sa_setreason(sa,
+                                   "unsupported group in INVALID_KE message");
+                               sa_state(env, sa, IKEV2_STATE_CLOSED);
+                               msg->msg_sa = NULL;
+                               return (-1);
+                       }
+                       if (protoid == IKEV2_SAPROTO_ESP) {
+                               /* CHILDSA */
+                               rekey.spi = sa->sa_rekeyspi;
+                               rekey.spi_size = 4;
+                               rekey.spi_protoid = protoid;
+                               (void)ikev2_send_create_child_sa(env, sa,
+                                   &rekey, rekey.spi_protoid, groupid);
+                       } else {
+                               /* IKESA */
+                               if ((group = group_get(groupid)) == NULL)
+                                       return -1;
+                               group_free(sa->sa_dhgroup);
+                               sa->sa_dhgroup = group;
+                               timer_set(env, &sa->sa_rekey,
+                                   ikev2_ike_sa_rekey, sa);
+                               timer_add(env, &sa->sa_rekey, 0);
+                       }
                        return (-1);
                }
-               msg->msg_policy->pol_peerdh = group;
-               log_debug("%s: responder selected DH group %u", __func__,
-                   group);
-               ikev2_ike_sa_setreason(sa,
-                   "reinitiating with new DH group");
-               sa_state(env, sa, IKEV2_STATE_CLOSED);
-               msg->msg_sa = NULL;
-
-               /*
-                * XXX should also happen for PFS so we have to check state.
-                */
-               timer_set(env, &env->sc_inittmr, ikev2_init_ike_sa, NULL);
-               timer_add(env, &env->sc_inittmr, IKED_INITIATOR_INITIAL);
-               return (-1);
        }
 
        if (msg->msg_flags & IKED_MSG_FLAGS_IPCOMP_SUPPORTED) {
@@ -3762,7 +3812,7 @@ ikev2_set_sa_proposal(struct iked_sa *sa, struct iked_policy *pol,
 
 int
 ikev2_send_create_child_sa(struct iked *env, struct iked_sa *sa,
-    struct iked_spi *rekey, uint8_t protoid)
+    struct iked_spi *rekey, uint8_t protoid, uint16_t proposed_group)
 {
        struct iked_policy              *pol = sa->sa_policy;
        struct iked_childsa             *csa = NULL, *csb = NULL;
@@ -3862,6 +3912,13 @@ ikev2_send_create_child_sa(struct iked *env, struct iked_sa *sa,
            protoid)) {
                log_debug("%s: enable PFS", __func__);
                ikev2_sa_cleanup_dh(sa);
+               if (proposed_group) {
+                       if ((sa->sa_dhgroup =
+                           group_get(proposed_group)) == NULL) {
+                               log_debug("%s: failed to get group", __func__);
+                               goto done;
+                       }
+               }
                if (ikev2_sa_initiator_dh(sa, NULL, protoid, NULL) < 0) {
                        log_debug("%s: failed to setup DH", __func__);
                        goto done;
@@ -6357,7 +6414,7 @@ ikev2_child_sa_acquire(struct iked *env, struct iked_flow *acquire)
                if (sa->sa_stateflags & (IKED_REQ_CHILDSA|IKED_REQ_INF))
                        return (-1);    /* busy, retry later */
                if (ikev2_send_create_child_sa(env, sa, NULL,
-                   flow->flow_saproto) != 0)
+                   flow->flow_saproto, 0) != 0)
                        log_warnx("%s: failed to initiate a "
                            "CREATE_CHILD_SA exchange", SPI_SA(sa, __func__));
        }
@@ -6407,7 +6464,7 @@ ikev2_child_sa_rekey(struct iked *env, struct iked_spi *rekey)
                return (-1);    /* peer is busy, retry later */
        if (csa->csa_allocated) /* Peer SPI died first, get the local one */
                rekey->spi = csa->csa_peerspi;
-       if (ikev2_send_create_child_sa(env, sa, rekey, rekey->spi_protoid))
+       if (ikev2_send_create_child_sa(env, sa, rekey, rekey->spi_protoid, 0))
                log_warnx("%s: failed to initiate a CREATE_CHILD_SA exchange",
                    SPI_SA(sa, __func__));
        return (0);