/* $OpenBSD: exchange.c,v 1.21 1999/06/02 06:33:00 niklas Exp $ */ /* $EOM: exchange.c,v 1.106 1999/05/21 14:12:57 ho Exp $ */ /* * Copyright (c) 1998, 1999 Niklas Hallqvist. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by Ericsson Radio Systems. * 4. The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /* * This code was written under funding by Ericsson Radio Systems. */ #include #include #include #include #include #include #include "sysdep.h" #include "cert.h" #include "conf.h" #include "constants.h" #include "cookie.h" #include "crypto.h" #include "doi.h" #include "exchange.h" #include "ipsec_num.h" #include "isakmp.h" #include "log.h" #include "message.h" #include "timer.h" #include "transport.h" #include "sa.h" #include "util.h" /* Initial number of bits from the cookies used as hash. */ #define INITIAL_BUCKET_BITS 6 /* * Don't try to use more bits than this as a hash. * We only XOR 16 bits so going above that means changing the code below * too. */ #define MAX_BUCKET_BITS 16 static void exchange_dump (char *, struct exchange *); static void exchange_free_aux (void *); static LIST_HEAD (exchange_list, exchange) *exchange_tab; /* Works both as a maximum index and a mask. */ static int bucket_mask; /* * Validation scripts used to test messages for correct content of * payloads depending on the exchange type. */ int16_t script_base[] = { ISAKMP_PAYLOAD_SA, /* Initiator -> responder. */ ISAKMP_PAYLOAD_NONCE, EXCHANGE_SCRIPT_SWITCH, ISAKMP_PAYLOAD_SA, /* Responder -> initiator. */ ISAKMP_PAYLOAD_NONCE, EXCHANGE_SCRIPT_SWITCH, ISAKMP_PAYLOAD_KEY_EXCH, /* Initiator -> responder. */ ISAKMP_PAYLOAD_ID, EXCHANGE_SCRIPT_AUTH, EXCHANGE_SCRIPT_SWITCH, ISAKMP_PAYLOAD_KEY_EXCH, /* Responder -> initiator. */ ISAKMP_PAYLOAD_ID, EXCHANGE_SCRIPT_AUTH, EXCHANGE_SCRIPT_END }; int16_t script_identity_protection[] = { ISAKMP_PAYLOAD_SA, /* Initiator -> responder. */ EXCHANGE_SCRIPT_SWITCH, ISAKMP_PAYLOAD_SA, /* Responder -> initiator. */ EXCHANGE_SCRIPT_SWITCH, ISAKMP_PAYLOAD_KEY_EXCH, /* Initiator -> responder. */ ISAKMP_PAYLOAD_NONCE, EXCHANGE_SCRIPT_SWITCH, ISAKMP_PAYLOAD_KEY_EXCH, /* Responder -> initiator. */ ISAKMP_PAYLOAD_NONCE, EXCHANGE_SCRIPT_SWITCH, ISAKMP_PAYLOAD_ID, /* Initiator -> responder. */ EXCHANGE_SCRIPT_AUTH, EXCHANGE_SCRIPT_SWITCH, ISAKMP_PAYLOAD_ID, /* Responder -> initiator. */ EXCHANGE_SCRIPT_AUTH, EXCHANGE_SCRIPT_END }; int16_t script_authentication_only[] = { ISAKMP_PAYLOAD_SA, /* Initiator -> responder. */ ISAKMP_PAYLOAD_NONCE, EXCHANGE_SCRIPT_SWITCH, ISAKMP_PAYLOAD_SA, /* Responder -> initiator. */ ISAKMP_PAYLOAD_NONCE, ISAKMP_PAYLOAD_ID, EXCHANGE_SCRIPT_AUTH, EXCHANGE_SCRIPT_SWITCH, ISAKMP_PAYLOAD_ID, /* Initiator -> responder. */ EXCHANGE_SCRIPT_AUTH, EXCHANGE_SCRIPT_END }; int16_t script_aggressive[] = { ISAKMP_PAYLOAD_SA, /* Initiator -> responder. */ ISAKMP_PAYLOAD_KEY_EXCH, ISAKMP_PAYLOAD_NONCE, ISAKMP_PAYLOAD_ID, EXCHANGE_SCRIPT_SWITCH, ISAKMP_PAYLOAD_SA, /* Responder -> initiator. */ ISAKMP_PAYLOAD_KEY_EXCH, ISAKMP_PAYLOAD_NONCE, ISAKMP_PAYLOAD_ID, EXCHANGE_SCRIPT_AUTH, EXCHANGE_SCRIPT_SWITCH, EXCHANGE_SCRIPT_AUTH, /* Initiator -> responder. */ EXCHANGE_SCRIPT_END }; int16_t script_informational[] = { EXCHANGE_SCRIPT_INFO, /* Initiator -> responder. */ EXCHANGE_SCRIPT_END }; /* * Check what exchange SA is negotiated with and return a suitable validation * script. */ u_int16_t * exchange_script (struct exchange *exchange) { switch (exchange->type) { case ISAKMP_EXCH_BASE: return script_base; case ISAKMP_EXCH_ID_PROT: return script_identity_protection; case ISAKMP_EXCH_AUTH_ONLY: return script_authentication_only; case ISAKMP_EXCH_AGGRESSIVE: return script_aggressive; case ISAKMP_EXCH_INFO: return script_informational; default: if (exchange->type >= ISAKMP_EXCH_DOI_MIN && exchange->type <= ISAKMP_EXCH_DOI_MAX) return exchange->doi->exchange_script (exchange->type); } return 0; } /* * Validate the message MSG's contents wrt what payloads the exchange type * requires at this point in the dialogoue. Return -1 if the validation fails, * 0 if it succeeds and the script is not finished and 1 if it's ready. */ static int exchange_validate (struct message *msg) { struct exchange *exchange = msg->exchange; int16_t *pc = exchange->exch_pc; while (*pc != EXCHANGE_SCRIPT_END && *pc != EXCHANGE_SCRIPT_SWITCH) { log_debug (LOG_EXCHANGE, 90, "exchange_validate: checking for required %s", *pc >= ISAKMP_PAYLOAD_NONE ? constant_name (isakmp_payload_cst, *pc) : constant_name (exchange_script_cst, *pc)); /* Check for existence of the required payloads. */ if ((*pc > 0 && !TAILQ_FIRST (&msg->payload[*pc])) || (*pc == EXCHANGE_SCRIPT_AUTH && !TAILQ_FIRST (&msg->payload[ISAKMP_PAYLOAD_HASH]) && !TAILQ_FIRST (&msg->payload[ISAKMP_PAYLOAD_SIG])) || (*pc == EXCHANGE_SCRIPT_INFO && !TAILQ_FIRST (&msg->payload[ISAKMP_PAYLOAD_NOTIFY]) && !TAILQ_FIRST (&msg->payload[ISAKMP_PAYLOAD_DELETE]))) { /* Missing payload. */ log_debug (LOG_MESSAGE, 70, "exchange_validate: msg %p requires missing %s", msg, *pc >= ISAKMP_PAYLOAD_NONE ? constant_name (isakmp_payload_cst, *pc) : constant_name (exchange_script_cst, *pc)); return -1; } pc++; } if (*pc == EXCHANGE_SCRIPT_END) /* Cleanup. */ return 1; return 0; } /* * Run the exchange script from a point given by the "program counter" * upto either the script's end or a transmittal of a message. If we are * at the point of a reception of a message, that message should be handed * in here in the MSG argument. Otherwise we are the initiator and should * expect MSG to be a half-cooked message without payloads. */ void exchange_run (struct message *msg) { int i, done = 0; struct exchange *exchange = msg->exchange; struct doi *doi = exchange->doi; int (*handler) (struct message *) = exchange->initiator ? doi->initiator : doi->responder; struct payload *payload; while (!done) { /* * It's our turn if we're either the initiator on an even step, * or the responder on an odd step of the dialogue. */ if (exchange->initiator ^ (exchange->step % 2)) { done = 1; if (exchange->step) msg = message_alloc_reply (msg); message_setup_header (msg, exchange->type, 0, exchange->message_id); if (handler (msg)) { /* * This can happen when transient starvation of memory occurs. * XXX The peer's retransmit ought to kick-start this exchange * again. If he's stopped retransmitting he's likely dropped * the SA at his side so we need to do that too, i.e. * implement automatic SA teardown after a certain amount * of inactivity. */ log_print ("exchange_run: doi->%s (%p) failed", exchange->initiator ? "initiator" : "responder", msg); message_free (msg); return; } switch (exchange_validate (msg)) { case 1: /* * The last message of a multi-message exchange should * not be retransmitted other than "on-demand", i.e. if we * see retransmits of the last message of the peer * later. */ msg->flags |= MSG_LAST; if (exchange->step > 0) { if (exchange->last_sent) message_free (exchange->last_sent); exchange->last_sent = msg; } /* * After we physically have sent our last message we need to * do SA-specific finalization, like telling our application * the SA is ready to be used, or issuing a CONNECTED notify * if we set the COMMIT bit. */ message_register_post_send (msg, exchange_finalize); /* Fallthrough. */ case 0: /* XXX error handling. */ message_send (msg); break; default: log_print ("exchange_run: exchange_validate failed, DOI error"); exchange_free (exchange); message_free (msg); return; } } else { done = exchange_validate (msg); switch (done) { case 0: case 1: /* Feed the message to the DOI. */ if (handler (msg)) { /* * Trust the peer to retransmit. * XXX We have to implement SA aging with automatic teardown. */ message_free (msg); return; } /* * Go over the yet unhandled payloads and feed them to DOI * for handling. */ for (i = ISAKMP_PAYLOAD_SA; i < ISAKMP_PAYLOAD_RESERVED_MIN; i++) if (i != ISAKMP_PAYLOAD_PROPOSAL && i != ISAKMP_PAYLOAD_TRANSFORM) for (payload = TAILQ_FIRST (&msg->payload[i]); payload; payload = TAILQ_NEXT (payload, link)) if ((payload->flags & PL_MARK) == 0) if (!doi->handle_leftover_payload || doi->handle_leftover_payload (msg, i, payload)) log_print ("exchange_run: unexpected payload %s", constant_name (isakmp_payload_cst, i)); /* * We have advanced the state. If we have been processing an * incoming message, record that message as the one to do * duplication tests against. */ if (exchange->last_received) message_free (exchange->last_received); exchange->last_received = msg; if (exchange->flags & EXCHANGE_FLAG_ENCRYPT) crypto_update_iv (exchange->keystate); if (done) { exchange_finalize (msg); return; } break; case -1: log_print ("exchange_run: exchange_validate failed"); /* XXX Is this the best error notification type? */ message_drop (msg, ISAKMP_NOTIFY_PAYLOAD_MALFORMED, 0, 1, 1); return; } } log_debug (LOG_EXCHANGE, 40, "exchange_run: exchange %p finished step %d, advancing...", exchange, exchange->step); exchange->step++; while (*exchange->exch_pc != EXCHANGE_SCRIPT_SWITCH && *exchange->exch_pc != EXCHANGE_SCRIPT_END) exchange->exch_pc++; exchange->exch_pc++; } } void exchange_init () { int i; bucket_mask = (1 << INITIAL_BUCKET_BITS) - 1; exchange_tab = malloc ((bucket_mask + 1) * sizeof (struct exchange_list)); if (!exchange_tab) log_fatal ("exchange_init: out of memory"); for (i = 0; i <= bucket_mask; i++) { LIST_INIT (&exchange_tab[i]); } } void exchange_resize () { int new_mask = (bucket_mask + 1) * 2 - 1; int i; struct exchange_list *new_tab; new_tab = realloc (exchange_tab, (new_mask + 1) * sizeof (struct exchange_list)); if (!new_tab) return; for (i = bucket_mask + 1; i <= new_mask; i++) { LIST_INIT (&new_tab[i]); } bucket_mask = new_mask; /* XXX Rehash existing entries. */ } /* Lookup a phase 1 exchange out of just the initiator cookie. */ struct exchange * exchange_lookup_from_icookie (u_int8_t *cookie) { int i; struct exchange *exchange; for (i = 0; i <= bucket_mask; i++) for (exchange = LIST_FIRST (&exchange_tab[i]); exchange; exchange = LIST_NEXT (exchange, link)) if (memcmp (exchange->cookies, cookie, ISAKMP_HDR_ICOOKIE_LEN) == 0 && exchange->phase == 1) return exchange; return 0; } /* Lookup an exchange out of the name and phase. */ struct exchange * exchange_lookup_by_name (char *name, int phase) { int i; struct exchange *exchange; /* If we search for nothing, we will find nothing. */ if (!name) return 0; for (i = 0; i <= bucket_mask; i++) for (exchange = LIST_FIRST (&exchange_tab[i]); exchange; exchange = LIST_NEXT (exchange, link)) { log_debug (LOG_EXCHANGE, 90, "exchange_lookup_by_name: %s == %s && %d == %d?", name, exchange->name ? exchange->name : "", phase, exchange->phase); /* * Match by name, but don't select finished exchanges, i.e * where MSG_LAST are set in last_sent msg. */ if (exchange->name && strcasecmp (exchange->name, name) == 0 && exchange->phase == phase && (!exchange->last_sent || (exchange->last_sent->flags & MSG_LAST) == 0)) return exchange; } return 0; } /* Lookup an exchange out of the name, phase and step > 1. */ struct exchange * exchange_lookup_active (char *name, int phase) { int i; struct exchange *exchange; /* XXX Almost identical to exchange_lookup_by_name. */ if (!name) return 0; for (i = 0; i <= bucket_mask; i++) for (exchange = LIST_FIRST (&exchange_tab[i]); exchange; exchange = LIST_NEXT (exchange, link)) { log_debug (LOG_EXCHANGE, 90, "exchange_lookup_active: %s == %s && %d == %d?", name, exchange->name ? exchange->name : "", phase, exchange->phase); if (exchange->name && strcasecmp (exchange->name, name) == 0 && exchange->phase == phase) { if (exchange->step > 1) return exchange; else log_debug (LOG_EXCHANGE, 80, "exchange_lookup_active: avoided early (pre-step 1) " "exchange %p", exchange); } } return 0; } static void exchange_enter (struct exchange *exchange) { u_int16_t bucket = 0; int i; u_int8_t *cp; /* XXX We might resize if we are crossing a certain threshold */ for (i = 0; i < ISAKMP_HDR_COOKIES_LEN; i += 2) { cp = exchange->cookies + i; /* Doing it this way avoids alignment problems. */ bucket ^= cp[0] | cp[1] << 8; } for (i = 0; i < ISAKMP_HDR_MESSAGE_ID_LEN; i += 2) { cp = exchange->message_id + i; /* Doing it this way avoids alignment problems. */ bucket ^= cp[0] | cp[1] << 8; } bucket &= bucket_mask; LIST_INSERT_HEAD (&exchange_tab[bucket], exchange, link); } /* * Lookup the exchange given by the header fields MSG. PHASE2 is false when * looking for phase 1 exchanges and true otherwise. */ struct exchange * exchange_lookup (u_int8_t *msg, int phase2) { u_int16_t bucket = 0; int i; struct exchange *exchange; u_int8_t *cp; /* * We use the cookies to get bits to use as an index into exchange_tab, as at * least one (our cookie) is a good hash, xoring all the bits, 16 at a * time, and then masking, should do. Doing it this way means we can * validate cookies very fast thus delimiting the effects of "Denial of * service"-attacks using packet flooding. */ for (i = 0; i < ISAKMP_HDR_COOKIES_LEN; i += 2) { cp = msg + ISAKMP_HDR_COOKIES_OFF + i; /* Doing it this way avoids alignment problems. */ bucket ^= cp[0] | cp[1] << 8; } if (phase2) for (i = 0; i < ISAKMP_HDR_MESSAGE_ID_LEN; i += 2) { cp = msg + ISAKMP_HDR_MESSAGE_ID_OFF + i; /* Doing it this way avoids alignment problems. */ bucket ^= cp[0] | cp[1] << 8; } bucket &= bucket_mask; for (exchange = LIST_FIRST (&exchange_tab[bucket]); exchange && (memcmp (msg + ISAKMP_HDR_COOKIES_OFF, exchange->cookies, ISAKMP_HDR_COOKIES_LEN) != 0 || (phase2 && memcmp (msg + ISAKMP_HDR_MESSAGE_ID_OFF, exchange->message_id, ISAKMP_HDR_MESSAGE_ID_LEN) != 0) || (!phase2 && !zero_test (msg + ISAKMP_HDR_MESSAGE_ID_OFF, ISAKMP_HDR_MESSAGE_ID_LEN))); exchange = LIST_NEXT (exchange, link)) ; return exchange; } /* * Create a phase PHASE exchange where INITIATOR denotes our role. DOI * is the domain of interpretation identifier and TYPE tells what exchange * type to use per either the DOI document or the ISAKMP spec proper. * NSA tells how many SAs we should pre-allocate, and should be zero * when we have the responder role. */ static struct exchange * exchange_create (int phase, int initiator, int doi, int type) { struct exchange *exchange; struct timeval expiration; int delta; /* * We want the exchange zeroed for exchange_free to be able to find * out what fields have been filled-in. */ exchange = calloc (1, sizeof *exchange); if (!exchange) { log_error ("exchange_create: calloc (1, %d) failed", sizeof *exchange); return 0; } exchange->phase = phase; exchange->step = 0; exchange->initiator = initiator; memset (exchange->cookies, 0, ISAKMP_HDR_COOKIES_LEN); memset (exchange->message_id, 0, ISAKMP_HDR_MESSAGE_ID_LEN); exchange->doi = doi_lookup (doi); exchange->type = type; exchange->exch_pc = exchange_script (exchange); exchange->last_sent = exchange->last_received = 0; TAILQ_INIT (&exchange->sa_list); TAILQ_INIT (&exchange->aca_list); /* Allocate the DOI-specific structure and initialize it to zeroes. */ if (exchange->doi->exchange_size) { exchange->data = calloc (1, exchange->doi->exchange_size); if (!exchange->data) { log_error ("exchange_create: calloc (1, %d) failed", exchange->doi->exchange_size); exchange_free (exchange); return 0; } } gettimeofday(&expiration, 0); delta = conf_get_num ("General", "Exchange-max-time", EXCHANGE_MAX_TIME); expiration.tv_sec += delta; exchange->death = timer_add_event ("exchange_free_aux", exchange_free_aux, exchange, &expiration); if (!exchange->death) { /* If we don't give up we might start leaking... */ exchange_free_aux (exchange); return 0; } return exchange; } struct exchange_finalization_node { void (*first) (struct exchange *, void *, int); void *first_arg; void (*second) (struct exchange *, void *, int); void *second_arg; }; /* Run the finalization functions of ARG. */ static void exchange_run_finalizations (struct exchange *exchange, void *arg, int fail) { struct exchange_finalization_node *node = arg; node->first (exchange, node->first_arg, fail); node->second (exchange, node->second_arg, fail); free (node); } /* * Add a finalization function FINALIZE with argument ARG to the tail * of the finalization function list of EXCHANGE. */ static void exchange_add_finalization (struct exchange *exchange, void (*finalize) (struct exchange *, void *, int), void *arg) { struct exchange_finalization_node *node; if (!finalize) return; if (!exchange->finalize) { exchange->finalize = finalize; exchange->finalize_arg = arg; return; } node = malloc (sizeof *node); if (!node) { log_error ("exchange_add_finalization: malloc (%d) failed", sizeof *node); free (arg); return; } node->first = exchange->finalize; node->first_arg = exchange->finalize_arg; node->second = finalize; node->second_arg = arg; exchange->finalize = exchange_run_finalizations; exchange->finalize_arg = node; } /* Establish a phase 1 exchange. */ void exchange_establish_p1 (struct transport *t, u_int8_t type, u_int32_t doi, char *name, void *args, void (*finalize) (struct exchange *, void *, int), void *arg) { struct exchange *exchange; struct message *msg; char *tag = 0; char *str; if (name) { /* If no exchange type given, fetch from the configuration. */ if (type == 0) { /* XXX Similar code can be found in exchange_setup_p1. Share? */ /* Find out our phase 1 mode. */ tag = conf_get_str (name, "Configuration"); if (!tag) { /* XXX I am not sure a default should be used. */ #if 0 tag = conf_get_str ("Phase 1", "Default"); if (!tag) { log_print ("exchange_establish_p1: " "no \"Default\" tag in [Phase 1] section"); return; } #else log_print ("exchange_establish_p1: " "no configuration found for peer \"%s\"", name); #endif } /* Figure out the DOI. XXX Factor out? */ str = conf_get_str (tag, "DOI"); if (!str) { log_print ("exchange_establish_p1: " "no \"DOI\" tag in [%s] section", tag); return; } if (strcasecmp (str, "ISAKMP") == 0) doi = ISAKMP_DOI_ISAKMP; else if (strcasecmp (str, "IPSEC") == 0) doi = IPSEC_DOI_IPSEC; else { log_print ("exchange_establish_p1: DOI \"%s\" unsupported", str); return; } /* What exchange type do we want? */ str = conf_get_str (tag, "EXCHANGE_TYPE"); if (!str) { log_print ("exchange_establish_p1: " "no \"EXCHANGE_TYPE\" tag in [%s] section", tag); return; } type = constant_value (isakmp_exch_cst, str); if (!type) { log_print ("exchange_establish_p1: unknown exchange type %s", str); return; } } } exchange = exchange_create (1, 1, doi, type); if (!exchange) { /* XXX Do something here? */ return; } if (name) { exchange->name = strdup (name); if (!exchange->name) { log_error ("exchange_establish_p1: strdup (\"%s\") failed", name); exchange_free (exchange); return; } } exchange->policy = name ? conf_get_str (name, "Configuration") : 0; exchange->finalize = finalize; exchange->finalize_arg = arg; cookie_gen (t, exchange, exchange->cookies, ISAKMP_HDR_ICOOKIE_LEN); exchange_enter (exchange); exchange_dump ("exchange_establish_p1", exchange); msg = message_alloc (t, 0, ISAKMP_HDR_SZ); msg->exchange = exchange; /* Do not create SA for an information exchange. */ if (exchange->type != ISAKMP_EXCH_INFO) { /* * Don't install a transport into this SA as it will be an INADDR_ANY * address in the local end, which is not good at all. Let the reply * packet install the transport instead. */ sa_create (exchange, 0); msg->isakmp_sa = TAILQ_FIRST (&exchange->sa_list); if (!msg->isakmp_sa) { /* XXX Do something more here? */ exchange_free (exchange); return; } } msg->extra = args; exchange_run (msg); } /* Establish a phase 2 exchange. XXX With just one SA for now. */ void exchange_establish_p2 (struct sa *isakmp_sa, u_int8_t type, char *name, void *args, void (*finalize) (struct exchange *, void *, int), void *arg) { struct exchange *exchange; struct message *msg; int i; char *tag, *str; u_int32_t doi = ISAKMP_DOI_ISAKMP; if (isakmp_sa) doi = isakmp_sa->doi->id; if (name) { /* Find out our phase 2 modes. */ tag = conf_get_str (name, "Configuration"); if (!tag) { log_print ("exchange_establish_p2: no configuration for peer \"%s\"", name); return; } /* Figure out the DOI. */ str = conf_get_str (tag, "DOI"); if (str) { if (strcasecmp (str, "IPSEC") == 0) doi = IPSEC_DOI_IPSEC; else { log_print ("exchange_establish_p2: DOI \"%s\" unsupported", str); return; } } /* What exchange type do we want? */ if (!type) { str = conf_get_str (tag, "EXCHANGE_TYPE"); if (!str) { log_print ("exchange_establish_p2: " "no \"EXCHANGE_TYPE\" tag in [%s] section", tag); return; } /* XXX IKE dependent. */ type = constant_value (ike_exch_cst, str); if (!type) { log_print ("exchange_establish_p2: unknown exchange type %s", str); return; } } } exchange = exchange_create (2, 1, doi, type); if (!exchange) { /* XXX Do something here? */ return; } if (name) { exchange->name = strdup (name); if (!exchange->name) { log_error ("exchange_establish_p2: strdup (\"%s\") failed", name); exchange_free (exchange); return; } } exchange->policy = name ? conf_get_str (name, "Configuration") : 0; exchange->finalize = finalize; exchange->finalize_arg = arg; memcpy (exchange->cookies, isakmp_sa->cookies, ISAKMP_HDR_COOKIES_LEN); getrandom (exchange->message_id, ISAKMP_HDR_MESSAGE_ID_LEN); exchange->flags |= EXCHANGE_FLAG_ENCRYPT; exchange_enter (exchange); exchange_dump ("exchange_establish_p2", exchange); /* * Do not create SA's for informational exchanges. * XXX How to handle new group mode? */ if (exchange->type != ISAKMP_EXCH_INFO) { /* XXX Number of SAs should come from the args structure. */ for (i = 0; i < 1; i++) if (sa_create (exchange, isakmp_sa->transport)) { exchange_free (exchange); return; } } msg = message_alloc (isakmp_sa->transport, 0, ISAKMP_HDR_SZ); msg->isakmp_sa = isakmp_sa; msg->extra = args; /* This needs to be done late or else get_keystate won't work right. */ msg->exchange = exchange; exchange_run (msg); } /* Out of an incoming phase 1 message, setup an exchange. */ struct exchange * exchange_setup_p1 (struct message *msg, u_int32_t doi) { struct transport *t = msg->transport; struct exchange *exchange; struct sockaddr *dst; int dst_len; char *name = 0, *policy = 0, *str; u_int32_t want_doi; u_int8_t type; /* XXX Similar code can be found in exchange_establish_p1. Share? */ /* * Unless this is an informational exchange, look up our policy for this * peer. */ type = GET_ISAKMP_HDR_EXCH_TYPE (msg->iov[0].iov_base); if (type != ISAKMP_EXCH_INFO) { /* * Find out our inbound phase 1 mode. * XXX Assumes IPv4. It might make sense to search through several * policies too. */ t->vtbl->get_dst (t, &dst, &dst_len); name = conf_get_str ("Phase 1", inet_ntoa (((struct sockaddr_in *)dst)->sin_addr)); if (name) { /* * If another phase 1 exchange is ongoing don't bother returning the * call. However, we will need to continue responding if our phase 1 * exchange is still waiting for step 1 (i.e still half-open). */ if (exchange_lookup_active (name, 1)) return 0; } else { name = conf_get_str ("Phase 1", "Default"); if (!name) { log_print ("exchange_setup_p1: " "no \"Default\" tag in [Phase 1] section"); return 0; } } policy = conf_get_str (name, "Configuration"); if (!policy) { log_print ("exchange_setup_p1: no configuration for peer \"%s\"", name); return 0; } /* Figure out the DOI. */ str = conf_get_str (policy, "DOI"); if (!str) { log_print ("exchange_setup_p1: no \"DOI\" tag in [%s] section", policy); return 0; } if (strcasecmp (str, "ISAKMP") == 0) want_doi = ISAKMP_DOI_ISAKMP; else if (strcasecmp (str, "IPSEC") == 0) want_doi = IPSEC_DOI_IPSEC; else { log_print ("exchange_setup_p1: DOI \"%s\" unsupported", str); return 0; } if (want_doi != doi) { /* XXX Should I tell what DOI I got? */ log_print ("exchange_setup_p1: expected %s DOI", str); return 0; } /* What exchange type do we want? */ str = conf_get_str (policy, "EXCHANGE_TYPE"); if (!str) { log_print ("exchange_setup_p1: " "no \"EXCHANGE_TYPE\" tag in [%s] section", policy); return 0; } type = constant_value (isakmp_exch_cst, str); if (!type) { log_print ("exchange_setup_p1: unknown exchange type %s", str); return 0; } if (type != GET_ISAKMP_HDR_EXCH_TYPE (msg->iov[0].iov_base)) { log_print ("exchange_setup_p1: expected exchange type %s got %s", str, constant_lookup (isakmp_exch_cst, GET_ISAKMP_HDR_EXCH_TYPE (msg->iov[0] .iov_base))); return 0; } } exchange = exchange_create (1, 0, doi, type); if (!exchange) return 0; exchange->name = name ? strdup (name) : 0; if (name && !exchange->name) { log_error ("exchange_setup_p1: strdup (\"%s\") failed", name); exchange_free (exchange); return 0; } exchange->policy = policy; cookie_gen (msg->transport, exchange, exchange->cookies + ISAKMP_HDR_ICOOKIE_LEN, ISAKMP_HDR_RCOOKIE_LEN); GET_ISAKMP_HDR_ICOOKIE (msg->iov[0].iov_base, exchange->cookies); exchange_enter (exchange); exchange_dump ("exchange_setup_p1", exchange); return exchange; } /* Out of an incoming phase 2 message, setup an exchange. */ struct exchange * exchange_setup_p2 (struct message *msg, u_int8_t doi) { struct exchange *exchange; u_int8_t *buf = msg->iov[0].iov_base; exchange = exchange_create (2, 0, doi, GET_ISAKMP_HDR_EXCH_TYPE (buf)); if (!exchange) return 0; GET_ISAKMP_HDR_ICOOKIE (buf, exchange->cookies); GET_ISAKMP_HDR_RCOOKIE (buf, exchange->cookies + ISAKMP_HDR_ICOOKIE_LEN); GET_ISAKMP_HDR_MESSAGE_ID (buf, exchange->message_id); exchange_enter (exchange); exchange_dump ("exchange_setup_p2", exchange); return exchange; } /* Dump interesting data about an exchange. */ static void exchange_dump_real (char *header, struct exchange *exchange, int class, int level) { char buf[LOG_SIZE]; /* Don't risk overflowing the final log buffer. */ int bufsize_max = LOG_SIZE - strlen (header) - 32; struct sa *sa; log_debug (class, level, "%s: %p %s %s policy %s phase %d doi %d exchange %d step %d", header, exchange, exchange->name ? exchange->name : "", exchange->policy ? exchange->policy : "", exchange->initiator ? "initiator" : "responder", exchange->phase, exchange->doi->id, exchange->type, exchange->step); log_debug (class, level, "%s: icookie %08x%08x rcookie %08x%08x", header, decode_32 (exchange->cookies), decode_32 (exchange->cookies + 4), decode_32 (exchange->cookies + 8), decode_32 (exchange->cookies + 12)); /* Include phase 2 SA list for this exchange */ if (exchange->phase == 2) { sprintf (buf, "sa_list "); for (sa = TAILQ_FIRST (&exchange->sa_list); sa && strlen (buf) < bufsize_max; sa = TAILQ_NEXT (sa, next)) sprintf (buf + strlen (buf), "%p ", sa); if (sa) strcat (buf, "..."); } else buf[0] = '\0'; log_debug (class, level, "%s: msgid %08x %s", header, decode_32 (exchange->message_id), buf); } static void exchange_dump (char *header, struct exchange *exchange) { exchange_dump_real (header, exchange, LOG_EXCHANGE, 10); } void exchange_report (void) { int i; struct exchange *exchange; for (i = 0; i <= bucket_mask; i++) for (exchange = LIST_FIRST (&exchange_tab[i]); exchange; exchange = LIST_NEXT (exchange, link)) exchange_dump_real ("exchange_report", exchange, LOG_REPORT, 0); } /* * Release all resources this exchange is using *except* for the "death" * event. When removing an exchange from the expiration handler that event * will be dealt with therein instead. */ static void exchange_free_aux (void *v_exch) { struct exchange *exchange = v_exch; struct sa *sa, *next_sa; log_debug (LOG_EXCHANGE, 80, "exchange_free_aux: freeing exchange %p", exchange); if (exchange->last_received) message_free (exchange->last_received); if (exchange->last_sent) message_free (exchange->last_sent); if (exchange->in_transit && exchange->in_transit != exchange->last_sent) message_free (exchange->in_transit); if (exchange->nonce_i) free (exchange->nonce_i); if (exchange->nonce_r) free (exchange->nonce_r); if (exchange->id_i) free (exchange->id_i); if (exchange->id_r) free (exchange->id_r); if (exchange->keystate) free (exchange->keystate); if (exchange->doi && exchange->doi->free_exchange_data) exchange->doi->free_exchange_data (exchange->data); if (exchange->data) free (exchange->data); if (exchange->name) free (exchange->name); exchange_free_aca_list (exchange); LIST_REMOVE (exchange, link); /* Tell potential finalize routine we never got there. */ if (exchange->finalize) exchange->finalize (exchange, exchange->finalize_arg, 1); /* Remove any SAs that has not been dissociated from us. */ for (sa = TAILQ_FIRST (&exchange->sa_list); sa; sa = next_sa) { next_sa = TAILQ_NEXT (sa, next); sa_free (sa); } free (exchange); } /* Release all resources this exchange is using. */ void exchange_free (struct exchange *exchange) { if (exchange->death) timer_remove_event (exchange->death); exchange_free_aux (exchange); } /* * Upgrade the phase 1 exchange and its ISAKMP SA with the rcookie of our * peer (found in his recently sent message MSG). */ void exchange_upgrade_p1 (struct message *msg) { struct exchange *exchange = msg->exchange; LIST_REMOVE (exchange, link); GET_ISAKMP_HDR_RCOOKIE (msg->iov[0].iov_base, exchange->cookies + ISAKMP_HDR_ICOOKIE_LEN); exchange_enter (exchange); sa_isakmp_upgrade (msg); } static int exchange_check_old_sa (struct sa *sa, void *v_arg) { struct sa *new_sa = v_arg; if (sa == new_sa || !sa->name || !(sa->flags & SA_FLAG_READY) || (sa->flags & SA_FLAG_REPLACED)) return 0; return sa->phase == new_sa->phase && new_sa->name && strcasecmp (sa->name, new_sa->name) == 0; } void exchange_finalize (struct message *msg) { struct exchange *exchange = msg->exchange; struct sa *sa, *old_sa; struct proto *proto; struct conf_list *attrs; struct conf_list_node *attr; int i; exchange_dump ("exchange_finalize", exchange); /* * Walk over all the SAs and noting them as ready. If we set the * COMMIT bit, tell the peer each SA is connected. * * XXX The decision should really be based on if a SA was installed * successfully. */ for (sa = TAILQ_FIRST (&exchange->sa_list); sa; sa = TAILQ_NEXT (sa, next)) { /* Move over the name to the SA. */ sa->name = exchange->name ? strdup (exchange->name) : 0; if (exchange->flags & EXCHANGE_FLAG_I_COMMITTED) { for (proto = TAILQ_FIRST (&sa->protos); proto; proto = TAILQ_NEXT (proto, link)) for (i = 0; i < 2; i++) message_send_notification (exchange->last_received, msg->isakmp_sa, ISAKMP_NOTIFY_STATUS_CONNECTED, proto, i); } /* Locate any old SAs and mark them replaced (SA_FLAG_REPLACED). */ while ((old_sa = sa_find (exchange_check_old_sa, sa)) != 0) sa_mark_replaced (old_sa); /* Setup the SA flags. */ sa->flags |= SA_FLAG_READY; if (exchange->name) { attrs = conf_get_list (exchange->name, "Flags"); if (attrs) { for (attr = TAILQ_FIRST (&attrs->fields); attr; attr = TAILQ_NEXT (attr, link)) sa->flags |= sa_flag (attr->field); conf_free_list (attrs); } } sa->exch_type = exchange->type; } /* * If this was an phase 1 SA negotiation, save the keystate in the ISAKMP SA * structure for future initialization of phase 2 exchanges' keystates. */ if (exchange->phase == 1 && msg->isakmp_sa) { msg->isakmp_sa->keystate = exchange->keystate; exchange->keystate = 0; } exchange->doi->finalize_exchange (msg); if (exchange->finalize) exchange->finalize (exchange, exchange->finalize_arg, 0); exchange->finalize = 0; /* * There is no reason to keep the SAs connected to us anymore, in fact * it can hurt us if we have short lifetimes on the SAs and we try * to call exchange_report, where the SA list will be walked and * references to freed SAs can occur. */ while (TAILQ_FIRST (&exchange->sa_list)) TAILQ_REMOVE (&exchange->sa_list, TAILQ_FIRST (&exchange->sa_list), next); /* If we have nothing to retransmit we can safely remove ourselves. */ if (!exchange->last_sent) exchange_free (exchange); } /* Stash a nonce into the exchange data. */ static int exchange_nonce (struct exchange *exchange, int peer, size_t nonce_sz, u_int8_t *buf) { int initiator = exchange->initiator ^ peer; u_int8_t **nonce; size_t *nonce_len; char header[32]; nonce = initiator ? &exchange->nonce_i : &exchange->nonce_r; nonce_len = initiator ? &exchange->nonce_i_len : &exchange->nonce_r_len; *nonce_len = nonce_sz; *nonce = malloc (nonce_sz); if (!*nonce) { log_error ("exchange_nonce: malloc (%d) failed", nonce_sz); return -1; } memcpy (*nonce, buf, nonce_sz); snprintf (header, 32, "exchange_nonce: NONCE_%c", initiator ? 'i' : 'r'); log_debug_buf (LOG_EXCHANGE, 80, header, *nonce, nonce_sz); return 0; } /* Generate our NONCE. */ int exchange_gen_nonce (struct message *msg, size_t nonce_sz) { struct exchange *exchange = msg->exchange; u_int8_t *buf; buf = malloc (ISAKMP_NONCE_SZ + nonce_sz); if (!buf) { log_error ("exchange_gen_nonce: malloc (%d) failed", ISAKMP_NONCE_SZ + nonce_sz); return -1; } getrandom (buf + ISAKMP_NONCE_DATA_OFF, nonce_sz); if (message_add_payload (msg, ISAKMP_PAYLOAD_NONCE, buf, ISAKMP_NONCE_SZ + nonce_sz, 1)) { free (buf); return -1; } return exchange_nonce (exchange, 0, nonce_sz, buf + ISAKMP_NONCE_DATA_OFF); } /* Save the peer's NONCE. */ int exchange_save_nonce (struct message *msg) { struct payload *noncep; struct exchange *exchange = msg->exchange; noncep = TAILQ_FIRST (&msg->payload[ISAKMP_PAYLOAD_NONCE]); noncep->flags |= PL_MARK; return exchange_nonce (exchange, 1, GET_ISAKMP_GEN_LENGTH (noncep->p) - ISAKMP_NONCE_DATA_OFF, noncep->p + ISAKMP_NONCE_DATA_OFF); } /* Save the peer's CERT REQuests. */ int exchange_save_certreq (struct message *msg) { struct payload *cp = TAILQ_FIRST (&msg->payload[ISAKMP_PAYLOAD_CERT_REQ]); struct exchange *exchange = msg->exchange; struct certreq_aca *tmp; for ( ; cp; cp = TAILQ_NEXT (cp, link)) { cp->flags |= PL_MARK; tmp = certreq_decode (GET_ISAKMP_CERTREQ_TYPE (cp->p), cp->p + ISAKMP_CERTREQ_AUTHORITY_OFF, GET_ISAKMP_GEN_LENGTH (cp->p) - ISAKMP_CERTREQ_AUTHORITY_OFF); if (!tmp) continue; TAILQ_INSERT_TAIL (&exchange->aca_list, tmp, link); } return 0; } /* Free the list of pending CERTREQ */ void exchange_free_aca_list (struct exchange *exchange) { struct certreq_aca *aca; for (aca = TAILQ_FIRST (&exchange->aca_list); aca; aca = TAILQ_FIRST (&exchange->aca_list)) { if (aca->data) { if (aca->handler) aca->handler->free_aca (aca->data); free (aca->data); } TAILQ_REMOVE (&exchange->aca_list, aca, link); free (aca); } } /* Obtain certificates from acceptable certification authority. */ int exchange_add_certs (struct message *msg) { struct exchange *exchange = msg->exchange; struct certreq_aca *aca; u_int8_t *cert; u_int32_t certlen; for (aca = TAILQ_FIRST (&exchange->aca_list); aca; aca = TAILQ_NEXT (aca, link)) { /* XXX? If we can not satisfy a CERTREQ we drop the message */ if (!aca->handler->cert_obtain (exchange, aca->data, &cert, &certlen)) { log_print ("exchange_add_certs: could not obtain cert for a type %d " "cert request", aca->id); return -1; } cert = realloc (cert, ISAKMP_CERT_SZ + certlen); if (!cert) { log_error ("exchange_add_certs: realloc (%p, %d) failed", cert, ISAKMP_CERT_SZ + certlen); return -1; } memmove (cert + ISAKMP_CERT_DATA_OFF, cert, certlen); SET_ISAKMP_CERT_ENCODING (cert, aca->id); if (message_add_payload (msg, ISAKMP_PAYLOAD_CERT, cert, ISAKMP_CERT_SZ + certlen, 1)) { free (cert); return -1; } } /* We dont need the CERT REQs any more, they are anwsered */ exchange_free_aca_list (exchange); return 0; } static void exchange_establish_finalize (struct exchange *exchange, void *arg, int fail) { char *name = arg; log_debug (LOG_EXCHANGE, 20, "exchange_establish_finalize: " "finalizing exchange %p with arg %p (%s) & fail = %d", exchange, arg, name ? name : "", fail); if (!fail) exchange_establish (name, 0, 0); free (name); } /* * Establish an exchange named NAME, and record the FINALIZE function * taking ARG as an argument to be run after the exchange is ready. */ void exchange_establish (char *name, void (*finalize) (struct exchange *, void *, int), void *arg) { int phase; char *trpt; struct transport *transport; char *peer; struct sa *isakmp_sa; struct exchange *exchange; phase = conf_get_num (name, "Phase", 0); /* * First of all, never try to establish anything if another exchange of the * same kind is running. */ exchange = exchange_lookup_by_name (name, phase); if (exchange) { log_debug (LOG_EXCHANGE, 40, "exchange_establish: %s exchange already exists as %p", name, exchange); exchange_add_finalization (exchange, finalize, arg); return; } switch (phase) { case 1: trpt = conf_get_str (name, "Transport"); if (!trpt) { log_print ("exchange_establish: No transport given for peer \"%s\"", name); return; } transport = transport_create (trpt, name); if (!transport) { log_print ("exchange_establish: " "transport \"%s\" for peer \"%s\" could not be created", trpt, name); return; } exchange_establish_p1 (transport, 0, 0, name, 0, finalize, arg); break; case 2: peer = conf_get_str (name, "ISAKMP-peer"); if (!peer) { log_print ("exchange_establish: No ISAKMP-peer given for \"%s\"", name); return; } isakmp_sa = sa_lookup_by_name (peer, 1); if (!isakmp_sa) { name = strdup (name); if (!name) { log_error ("exchange_establish: strdup(\"%s\") failed", name); return; } exchange_establish (peer, exchange_establish_finalize, name); } else exchange_establish_p2 (isakmp_sa, 0, name, 0, finalize, arg); break; default: log_print ("exchange_establish: " "peer \"%s\" does not have a correct phase (%d)", name, phase); break; } }