/* Security Policy Data Base (such as it is) * Copyright (C) 1998-2001 D. Hugh Redelmeier. * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the * Free Software Foundation; either version 2 of the License, or (at your * option) any later version. See . * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * for more details. * * RCSID $Id: spdb.c 3845 2008-04-18 17:00:30Z andreas $ */ #include #include #include #include #include #include #include #include #include #include "constants.h" #include "defs.h" #include "id.h" #include "connections.h" #include "state.h" #include "packet.h" #include "keys.h" #include "kernel.h" #include "log.h" #include "spdb.h" #include "whack.h" #include "sha1.h" #include "md5.h" #include "crypto.h" /* requires sha1.h and md5.h */ #include "alg_info.h" #include "kernel_alg.h" #include "ike_alg.h" #include "db_ops.h" #include "nat_traversal.h" #define AD(x) x, elemsof(x) /* Array Description */ #define AD_NULL NULL, 0 /**************** Oakely (main mode) SA database ****************/ /* array of proposals to be conjoined (can only be one for Oakley) */ static struct db_prop oakley_pc[] = { { PROTO_ISAKMP, AD_NULL } }; /* array of proposal conjuncts (can only be one) */ static struct db_prop_conj oakley_props[] = { { AD(oakley_pc) } }; /* the sadb entry */ struct db_sa oakley_sadb = { AD(oakley_props) }; /**************** IPsec (quick mode) SA database ****************/ /* arrays of attributes for transforms */ static struct db_attr espsha1_attr[] = { { AUTH_ALGORITHM, AUTH_ALGORITHM_HMAC_SHA1 }, }; static struct db_attr ah_HMAC_SHA1_attr[] = { { AUTH_ALGORITHM, AUTH_ALGORITHM_HMAC_SHA1 }, }; /* arrays of transforms, each in in preference order */ static struct db_trans espa_trans[] = { { ESP_3DES, AD(espsha1_attr) }, }; static struct db_trans esp_trans[] = { { ESP_3DES, AD_NULL }, }; #ifdef SUPPORT_ESP_NULL static struct db_trans espnull_trans[] = { { ESP_NULL, AD(espsha1_attr) }, }; #endif /* SUPPORT_ESP_NULL */ static struct db_trans ah_trans[] = { { AH_SHA, AD(ah_HMAC_SHA1_attr) }, }; static struct db_trans ipcomp_trans[] = { { IPCOMP_DEFLATE, AD_NULL }, }; /* arrays of proposals to be conjoined */ static struct db_prop ah_pc[] = { { PROTO_IPSEC_AH, AD(ah_trans) }, }; #ifdef SUPPORT_ESP_NULL static struct db_prop espnull_pc[] = { { PROTO_IPSEC_ESP, AD(espnull_trans) }, }; #endif /* SUPPORT_ESP_NULL */ static struct db_prop esp_pc[] = { { PROTO_IPSEC_ESP, AD(espa_trans) }, }; static struct db_prop ah_esp_pc[] = { { PROTO_IPSEC_AH, AD(ah_trans) }, { PROTO_IPSEC_ESP, AD(esp_trans) }, }; static struct db_prop compress_pc[] = { { PROTO_IPCOMP, AD(ipcomp_trans) }, }; static struct db_prop ah_compress_pc[] = { { PROTO_IPSEC_AH, AD(ah_trans) }, { PROTO_IPCOMP, AD(ipcomp_trans) }, }; #ifdef SUPPORT_ESP_NULL static struct db_prop espnull_compress_pc[] = { { PROTO_IPSEC_ESP, AD(espnull_trans) }, { PROTO_IPCOMP, AD(ipcomp_trans) }, }; #endif /* SUPPORT_ESP_NULL */ static struct db_prop esp_compress_pc[] = { { PROTO_IPSEC_ESP, AD(espa_trans) }, { PROTO_IPCOMP, AD(ipcomp_trans) }, }; static struct db_prop ah_esp_compress_pc[] = { { PROTO_IPSEC_AH, AD(ah_trans) }, { PROTO_IPSEC_ESP, AD(esp_trans) }, { PROTO_IPCOMP, AD(ipcomp_trans) }, }; /* arrays of proposal alternatives (each element is a conjunction) */ static struct db_prop_conj ah_props[] = { { AD(ah_pc) }, #ifdef SUPPORT_ESP_NULL { AD(espnull_pc) } #endif }; static struct db_prop_conj esp_props[] = { { AD(esp_pc) } }; static struct db_prop_conj ah_esp_props[] = { { AD(ah_esp_pc) } }; static struct db_prop_conj compress_props[] = { { AD(compress_pc) }, }; static struct db_prop_conj ah_compress_props[] = { { AD(ah_compress_pc) }, #ifdef SUPPORT_ESP_NULL { AD(espnull_compress_pc) } #endif }; static struct db_prop_conj esp_compress_props[] = { { AD(esp_compress_pc) } }; static struct db_prop_conj ah_esp_compress_props[] = { { AD(ah_esp_compress_pc) } }; /* The IPsec sadb is subscripted by a bitset (subset of policy) * with members from { POLICY_ENCRYPT, POLICY_AUTHENTICATE, POLICY_COMPRESS } * shifted right by POLICY_IPSEC_SHIFT. */ struct db_sa ipsec_sadb[1 << 3] = { { AD_NULL }, /* none */ { AD(esp_props) }, /* POLICY_ENCRYPT */ { AD(ah_props) }, /* POLICY_AUTHENTICATE */ { AD(ah_esp_props) }, /* POLICY_ENCRYPT+POLICY_AUTHENTICATE */ { AD(compress_props) }, /* POLICY_COMPRESS */ { AD(esp_compress_props) }, /* POLICY_ENCRYPT+POLICY_COMPRESS */ { AD(ah_compress_props) }, /* POLICY_AUTHENTICATE+POLICY_COMPRESS */ { AD(ah_esp_compress_props) }, /* POLICY_ENCRYPT+POLICY_AUTHENTICATE+POLICY_COMPRESS */ }; #undef AD #undef AD_NULL /* output an attribute (within an SA) */ static bool out_attr(int type , unsigned long val , struct_desc *attr_desc , enum_names **attr_val_descs USED_BY_DEBUG , pb_stream *pbs) { struct isakmp_attribute attr; if (val >> 16 == 0) { /* short value: use TV form */ attr.isaat_af_type = type | ISAKMP_ATTR_AF_TV; attr.isaat_lv = val; if (!out_struct(&attr, attr_desc, pbs, NULL)) return FALSE; } else { /* This is a real fudge! Since we rarely use long attributes * and since this is the only place where we can cause an * ISAKMP message length to be other than a multiple of 4 octets, * we force the length of the value to be a multiple of 4 octets. * Furthermore, we only handle values up to 4 octets in length. * Voila: a fixed format! */ pb_stream val_pbs; u_int32_t nval = htonl(val); attr.isaat_af_type = type | ISAKMP_ATTR_AF_TLV; if (!out_struct(&attr, attr_desc, pbs, &val_pbs) || !out_raw(&nval, sizeof(nval), &val_pbs, "long attribute value")) return FALSE; close_output_pbs(&val_pbs); } DBG(DBG_EMITTING, enum_names *d = attr_val_descs[type]; if (d != NULL) DBG_log(" [%lu is %s]" , val, enum_show(d, val))); return TRUE; } #define return_on(var, val) do { var=val;goto return_out; } while(0); /* Output an SA, as described by a db_sa. * This has the side-effect of allocating SPIs for us. */ bool out_sa(pb_stream *outs , struct db_sa *sadb , struct state *st , bool oakley_mode , u_int8_t np) { pb_stream sa_pbs; int pcn; bool ret = FALSE; bool ah_spi_generated = FALSE , esp_spi_generated = FALSE , ipcomp_cpi_generated = FALSE; #if !defined NO_KERNEL_ALG || !defined NO_IKE_ALG struct db_context *db_ctx = NULL; #endif /* SA header out */ { struct isakmp_sa sa; sa.isasa_np = np; st->st_doi = sa.isasa_doi = ISAKMP_DOI_IPSEC; /* all we know */ if (!out_struct(&sa, &isakmp_sa_desc, outs, &sa_pbs)) return_on(ret, FALSE); } /* within SA: situation out */ st->st_situation = SIT_IDENTITY_ONLY; if (!out_struct(&st->st_situation, &ipsec_sit_desc, &sa_pbs, NULL)) return_on(ret, FALSE); /* within SA: Proposal Payloads * * Multiple Proposals with the same number are simultaneous * (conjuncts) and must deal with different protocols (AH or ESP). * Proposals with different numbers are alternatives (disjuncts), * in preference order. * Proposal numbers must be monotonic. * See RFC 2408 "ISAKMP" 4.2 */ for (pcn = 0; pcn != sadb->prop_conj_cnt; pcn++) { struct db_prop_conj *pc = &sadb->prop_conjs[pcn]; int pn; for (pn = 0; pn != pc->prop_cnt; pn++) { struct db_prop *p = &pc->props[pn]; pb_stream proposal_pbs; struct isakmp_proposal proposal; struct_desc *trans_desc = NULL; struct_desc *attr_desc = NULL; enum_names **attr_val_descs = NULL; int tn; bool tunnel_mode; tunnel_mode = (pn == pc->prop_cnt-1) && (st->st_policy & POLICY_TUNNEL); /* Proposal header */ proposal.isap_np = pcn == sadb->prop_conj_cnt-1 && pn == pc->prop_cnt-1 ? ISAKMP_NEXT_NONE : ISAKMP_NEXT_P; proposal.isap_proposal = pcn; proposal.isap_protoid = p->protoid; proposal.isap_spisize = oakley_mode ? 0 : p->protoid == PROTO_IPCOMP ? IPCOMP_CPI_SIZE : IPSEC_DOI_SPI_SIZE; /* In quick mode ONLY, create proposal for runtime kernel algos. * Replace ESP proposals with runtime created one */ if (!oakley_mode && p->protoid == PROTO_IPSEC_ESP) { DBG(DBG_CONTROL | DBG_CRYPT, if (st->st_connection->alg_info_esp) { static char buf[256]=""; alg_info_snprint(buf, sizeof (buf), (struct alg_info *)st->st_connection->alg_info_esp); DBG_log(buf); } ) db_ctx = kernel_alg_db_new(st->st_connection->alg_info_esp, st->st_policy); p = db_prop_get(db_ctx); if (!p || p->trans_cnt == 0) { loglog(RC_LOG_SERIOUS, "empty IPSEC SA proposal to send " "(no kernel algorithms for esp selection)"); return_on(ret, FALSE); } } if (oakley_mode && p->protoid == PROTO_ISAKMP) { DBG(DBG_CONTROL | DBG_CRYPT, if (st->st_connection->alg_info_ike) { static char buf[256]=""; alg_info_snprint(buf, sizeof (buf), (struct alg_info *)st->st_connection->alg_info_ike); DBG_log(buf); } ) db_ctx = ike_alg_db_new(st->st_connection->alg_info_ike, st->st_policy); p = db_prop_get(db_ctx); if (!p || p->trans_cnt == 0) { loglog(RC_LOG_SERIOUS, "empty ISAKMP SA proposal to send " "(no algorithms for ike selection?)"); return_on(ret, FALSE); } } proposal.isap_notrans = p->trans_cnt; if (!out_struct(&proposal, &isakmp_proposal_desc, &sa_pbs, &proposal_pbs)) return_on(ret, FALSE); /* Per-protocols stuff: * Set trans_desc. * Set attr_desc. * Set attr_val_descs. * If not oakley_mode, emit SPI. * We allocate SPIs on demand. * All ESPs in an SA will share a single SPI. * All AHs in an SAwill share a single SPI. * AHs' SPI will be distinct from ESPs'. * This latter is needed because KLIPS doesn't * use the protocol when looking up a (dest, protocol, spi). * ??? If multiple ESPs are composed, how should their SPIs * be allocated? */ { ipsec_spi_t *spi_ptr = NULL; int proto = 0; bool *spi_generated = NULL; switch (p->protoid) { case PROTO_ISAKMP: passert(oakley_mode); trans_desc = &isakmp_isakmp_transform_desc; attr_desc = &isakmp_oakley_attribute_desc; attr_val_descs = oakley_attr_val_descs; /* no SPI needed */ break; case PROTO_IPSEC_AH: passert(!oakley_mode); trans_desc = &isakmp_ah_transform_desc; attr_desc = &isakmp_ipsec_attribute_desc; attr_val_descs = ipsec_attr_val_descs; spi_ptr = &st->st_ah.our_spi; spi_generated = &ah_spi_generated; proto = IPPROTO_AH; break; case PROTO_IPSEC_ESP: passert(!oakley_mode); trans_desc = &isakmp_esp_transform_desc; attr_desc = &isakmp_ipsec_attribute_desc; attr_val_descs = ipsec_attr_val_descs; spi_ptr = &st->st_esp.our_spi; spi_generated = &esp_spi_generated; proto = IPPROTO_ESP; break; case PROTO_IPCOMP: passert(!oakley_mode); trans_desc = &isakmp_ipcomp_transform_desc; attr_desc = &isakmp_ipsec_attribute_desc; attr_val_descs = ipsec_attr_val_descs; /* a CPI isn't quite the same as an SPI * so we use specialized code to emit it. */ if (!ipcomp_cpi_generated) { st->st_ipcomp.our_spi = get_my_cpi( &st->st_connection->spd, tunnel_mode); if (st->st_ipcomp.our_spi == 0) return_on(ret, FALSE); /* problem generating CPI */ ipcomp_cpi_generated = TRUE; } /* CPI is stored in network low order end of an * ipsec_spi_t. So we start a couple of bytes in. */ if (!out_raw((u_char *)&st->st_ipcomp.our_spi + IPSEC_DOI_SPI_SIZE - IPCOMP_CPI_SIZE , IPCOMP_CPI_SIZE , &proposal_pbs, "CPI")) return_on(ret, FALSE); break; default: bad_case(p->protoid); } if (spi_ptr != NULL) { if (!*spi_generated) { *spi_ptr = get_ipsec_spi(0 , proto , &st->st_connection->spd , tunnel_mode); if (*spi_ptr == 0) return FALSE; *spi_generated = TRUE; } if (!out_raw((u_char *)spi_ptr, IPSEC_DOI_SPI_SIZE , &proposal_pbs, "SPI")) return_on(ret, FALSE); } } /* within proposal: Transform Payloads */ for (tn = 0; tn != p->trans_cnt; tn++) { struct db_trans *t = &p->trans[tn]; pb_stream trans_pbs; struct isakmp_transform trans; int an; trans.isat_np = (tn == p->trans_cnt - 1) ? ISAKMP_NEXT_NONE : ISAKMP_NEXT_T; trans.isat_transnum = tn; trans.isat_transid = t->transid; if (!out_struct(&trans, trans_desc, &proposal_pbs, &trans_pbs)) return_on(ret, FALSE); /* Within tranform: Attributes. */ /* For Phase 2 / Quick Mode, GROUP_DESCRIPTION is * automatically generated because it must be the same * in every transform. Except IPCOMP. */ if (p->protoid != PROTO_IPCOMP && st->st_pfs_group != NULL) { passert(!oakley_mode); passert(st->st_pfs_group != &unset_group); out_attr(GROUP_DESCRIPTION, st->st_pfs_group->group , attr_desc, attr_val_descs , &trans_pbs); } /* automatically generate duration * and, for Phase 2 / Quick Mode, encapsulation. */ if (oakley_mode) { out_attr(OAKLEY_LIFE_TYPE, OAKLEY_LIFE_SECONDS , attr_desc, attr_val_descs , &trans_pbs); out_attr(OAKLEY_LIFE_DURATION , st->st_connection->sa_ike_life_seconds , attr_desc, attr_val_descs , &trans_pbs); } else { /* RFC 2407 (IPSEC DOI) 4.5 specifies that * the default is "unspecified (host-dependent)". * This makes little sense, so we always specify it. * * Unlike other IPSEC transforms, IPCOMP defaults * to Transport Mode, so we can exploit the default * (draft-shacham-ippcp-rfc2393bis-05.txt 4.1). */ if (p->protoid != PROTO_IPCOMP || st->st_policy & POLICY_TUNNEL) { #ifndef I_KNOW_TRANSPORT_MODE_HAS_SECURITY_CONCERN_BUT_I_WANT_IT if ((st->nat_traversal & NAT_T_DETECTED) && !(st->st_policy & POLICY_TUNNEL)) { /* Inform user that we will not respect policy and only * propose Tunnel Mode */ loglog(RC_LOG_SERIOUS, "NAT-Traversal: " "Transport Mode not allowed due to security concerns -- " "using Tunnel mode"); } #endif out_attr(ENCAPSULATION_MODE #ifdef I_KNOW_TRANSPORT_MODE_HAS_SECURITY_CONCERN_BUT_I_WANT_IT , NAT_T_ENCAPSULATION_MODE(st, st->st_policy) #else /* If NAT-T is detected, use UDP_TUNNEL as long as Transport * Mode has security concerns. * * User has been informed of that */ , NAT_T_ENCAPSULATION_MODE(st, POLICY_TUNNEL) #endif , attr_desc, attr_val_descs , &trans_pbs); } out_attr(SA_LIFE_TYPE, SA_LIFE_TYPE_SECONDS , attr_desc, attr_val_descs , &trans_pbs); out_attr(SA_LIFE_DURATION , st->st_connection->sa_ipsec_life_seconds , attr_desc, attr_val_descs , &trans_pbs); } /* spit out attributes from table */ for (an = 0; an != t->attr_cnt; an++) { struct db_attr *a = &t->attrs[an]; out_attr(a->type, a->val , attr_desc, attr_val_descs , &trans_pbs); } close_output_pbs(&trans_pbs); } close_output_pbs(&proposal_pbs); } /* end of a conjunction of proposals */ } close_output_pbs(&sa_pbs); ret = TRUE; return_out: #if !defined NO_KERNEL_ALG || !defined NO_IKE_ALG if (db_ctx) db_destroy(db_ctx); #endif return ret; } /* Handle long form of duration attribute. * The code is can only handle values that can fit in unsigned long. * "Clamping" is probably an acceptable way to impose this limitation. */ static u_int32_t decode_long_duration(pb_stream *pbs) { u_int32_t val = 0; /* ignore leading zeros */ while (pbs_left(pbs) != 0 && *pbs->cur == '\0') pbs->cur++; if (pbs_left(pbs) > sizeof(val)) { /* "clamp" too large value to max representable value */ val -= 1; /* portable way to get to maximum value */ DBG(DBG_PARSING, DBG_log(" too large duration clamped to: %lu" , (unsigned long)val)); } else { /* decode number */ while (pbs_left(pbs) != 0) val = (val << BITS_PER_BYTE) | *pbs->cur++; DBG(DBG_PARSING, DBG_log(" long duration: %lu", (unsigned long)val)); } return val; } /* Preparse the body of an ISAKMP SA Payload and * return body of ISAKMP Proposal Payload * * Only IPsec DOI is accepted (what is the ISAKMP DOI?). * Error response is rudimentary. */ notification_t preparse_isakmp_sa_body(const struct isakmp_sa *sa , pb_stream *sa_pbs , u_int32_t *ipsecdoisit , pb_stream *proposal_pbs , struct isakmp_proposal *proposal) { /* DOI */ if (sa->isasa_doi != ISAKMP_DOI_IPSEC) { loglog(RC_LOG_SERIOUS, "Unknown/unsupported DOI %s", enum_show(&doi_names, sa->isasa_doi)); /* XXX Could send notification back */ return DOI_NOT_SUPPORTED; } /* Situation */ if (!in_struct(ipsecdoisit, &ipsec_sit_desc, sa_pbs, NULL)) return SITUATION_NOT_SUPPORTED; if (*ipsecdoisit != SIT_IDENTITY_ONLY) { loglog(RC_LOG_SERIOUS, "unsupported IPsec DOI situation (%s)" , bitnamesof(sit_bit_names, *ipsecdoisit)); /* XXX Could send notification back */ return SITUATION_NOT_SUPPORTED; } /* The rules for ISAKMP SAs are scattered. * RFC 2409 "IKE" section 5 says that there * can only be one SA, and it can have only one proposal in it. * There may well be multiple transforms. */ if (!in_struct(proposal, &isakmp_proposal_desc, sa_pbs, proposal_pbs)) return PAYLOAD_MALFORMED; if (proposal->isap_np != ISAKMP_NEXT_NONE) { loglog(RC_LOG_SERIOUS, "Proposal Payload must be alone in Oakley SA; found %s following Proposal" , enum_show(&payload_names, proposal->isap_np)); return PAYLOAD_MALFORMED; } if (proposal->isap_protoid != PROTO_ISAKMP) { loglog(RC_LOG_SERIOUS, "unexpected Protocol ID (%s) found in Oakley Proposal" , enum_show(&protocol_names, proposal->isap_protoid)); return INVALID_PROTOCOL_ID; } /* Just what should we accept for the SPI field? * The RFC is sort of contradictory. We will ignore the SPI * as long as it is of the proper size. * * From RFC2408 2.4 Identifying Security Associations: * During phase 1 negotiations, the initiator and responder cookies * determine the ISAKMP SA. Therefore, the SPI field in the Proposal * payload is redundant and MAY be set to 0 or it MAY contain the * transmitting entity's cookie. * * From RFC2408 3.5 Proposal Payload: * o SPI Size (1 octet) - Length in octets of the SPI as defined by * the Protocol-Id. In the case of ISAKMP, the Initiator and * Responder cookie pair from the ISAKMP Header is the ISAKMP SPI, * therefore, the SPI Size is irrelevant and MAY be from zero (0) to * sixteen (16). If the SPI Size is non-zero, the content of the * SPI field MUST be ignored. If the SPI Size is not a multiple of * 4 octets it will have some impact on the SPI field and the * alignment of all payloads in the message. The Domain of * Interpretation (DOI) will dictate the SPI Size for other * protocols. */ if (proposal->isap_spisize == 0) { /* empty (0) SPI -- fine */ } else if (proposal->isap_spisize <= MAX_ISAKMP_SPI_SIZE) { u_char junk_spi[MAX_ISAKMP_SPI_SIZE]; if (!in_raw(junk_spi, proposal->isap_spisize, proposal_pbs, "Oakley SPI")) return PAYLOAD_MALFORMED; } else { loglog(RC_LOG_SERIOUS, "invalid SPI size (%u) in Oakley Proposal" , (unsigned)proposal->isap_spisize); return INVALID_SPI; } return NOTHING_WRONG; } static struct { u_int8_t *start; u_int8_t *cur; u_int8_t *roof; } backup; /* * backup the pointer into a pb_stream */ void backup_pbs(pb_stream *pbs) { backup.start = pbs->start; backup.cur = pbs->cur; backup.roof = pbs->roof; } /* * restore the pointer into a pb_stream */ void restore_pbs(pb_stream *pbs) { pbs->start = backup.start; pbs->cur = backup.cur; pbs->roof = backup.roof; } /* * Parse an ISAKMP Proposal Payload for RSA and PSK authentication policies */ notification_t parse_isakmp_policy(pb_stream *proposal_pbs , u_int notrans , lset_t *policy) { int last_transnum = -1; *policy = LEMPTY; while (notrans--) { pb_stream trans_pbs; u_char *attr_start; size_t attr_len; struct isakmp_transform trans; if (!in_struct(&trans, &isakmp_isakmp_transform_desc, proposal_pbs, &trans_pbs)) return BAD_PROPOSAL_SYNTAX; if (trans.isat_transnum <= last_transnum) { /* picky, picky, picky */ loglog(RC_LOG_SERIOUS, "Transform Numbers are not monotonically increasing" " in Oakley Proposal"); return BAD_PROPOSAL_SYNTAX; } last_transnum = trans.isat_transnum; if (trans.isat_transid != KEY_IKE) { loglog(RC_LOG_SERIOUS, "expected KEY_IKE but found %s in Oakley Transform" , enum_show(&isakmp_transformid_names, trans.isat_transid)); return INVALID_TRANSFORM_ID; } attr_start = trans_pbs.cur; attr_len = pbs_left(&trans_pbs); /* preprocess authentication attributes only */ while (pbs_left(&trans_pbs) != 0) { struct isakmp_attribute a; pb_stream attr_pbs; if (!in_struct(&a, &isakmp_oakley_attribute_desc, &trans_pbs, &attr_pbs)) return BAD_PROPOSAL_SYNTAX; passert((a.isaat_af_type & ISAKMP_ATTR_RTYPE_MASK) < 32); switch (a.isaat_af_type) { case OAKLEY_AUTHENTICATION_METHOD | ISAKMP_ATTR_AF_TV: switch (a.isaat_lv) { case OAKLEY_PRESHARED_KEY: *policy |= POLICY_PSK; break; case OAKLEY_RSA_SIG: *policy |= POLICY_RSASIG; break; case XAUTHInitPreShared: *policy |= POLICY_XAUTH_SERVER; /* fall through */ case XAUTHRespPreShared: *policy |= POLICY_XAUTH_PSK; break; case XAUTHInitRSA: *policy |= POLICY_XAUTH_SERVER; /* fall through */ case XAUTHRespRSA: *policy |= POLICY_XAUTH_RSASIG; break; default: break; } break; default: break; } } } DBG(DBG_CONTROL|DBG_PARSING, DBG_log("preparse_isakmp_policy: peer requests %s authentication" , prettypolicy(*policy)) ) return NOTHING_WRONG; } /* * check that we can find a preshared secret */ static err_t find_preshared_key(struct state* st) { err_t ugh = NULL; struct connection *c = st->st_connection; if (get_preshared_secret(c) == NULL) { char my_id[BUF_LEN], his_id[BUF_LEN]; idtoa(&c->spd.this.id, my_id, sizeof(my_id)); if (his_id_was_instantiated(c)) strcpy(his_id, "%any"); else idtoa(&c->spd.that.id, his_id, sizeof(his_id)); ugh = builddiag("Can't authenticate: no preshared key found for `%s' and `%s'" , my_id, his_id); } return ugh; } /* Parse the body of an ISAKMP SA Payload (i.e. Phase 1 / Main Mode). * Various shortcuts are taken. In particular, the policy, such as * it is, is hardwired. * * If r_sa is non-NULL, the body of an SA representing the selected * proposal is emitted. * * This routine is used by main_inI1_outR1() and main_inR1_outI2(). */ notification_t parse_isakmp_sa_body(u_int32_t ipsecdoisit , pb_stream *proposal_pbs , struct isakmp_proposal *proposal , pb_stream *r_sa_pbs , struct state *st , bool initiator) { struct connection *c = st->st_connection; unsigned no_trans_left; /* for each transform payload... */ no_trans_left = proposal->isap_notrans; for (;;) { pb_stream trans_pbs; u_char *attr_start; size_t attr_len; struct isakmp_transform trans; lset_t seen_attrs = 0; lset_t seen_durations = 0; u_int16_t life_type = 0; struct oakley_trans_attrs ta; err_t ugh = NULL; /* set to diagnostic when problem detected */ /* initialize only optional field in ta */ ta.life_seconds = OAKLEY_ISAKMP_SA_LIFETIME_DEFAULT; /* When this SA expires (seconds) */ if (no_trans_left == 0) { loglog(RC_LOG_SERIOUS, "number of Transform Payloads disagrees with Oakley Proposal Payload"); return BAD_PROPOSAL_SYNTAX; } in_struct(&trans, &isakmp_isakmp_transform_desc, proposal_pbs, &trans_pbs); attr_start = trans_pbs.cur; attr_len = pbs_left(&trans_pbs); /* process all the attributes that make up the transform */ while (pbs_left(&trans_pbs) != 0) { struct isakmp_attribute a; pb_stream attr_pbs; u_int32_t val; /* room for larger values */ if (!in_struct(&a, &isakmp_oakley_attribute_desc, &trans_pbs, &attr_pbs)) return BAD_PROPOSAL_SYNTAX; passert((a.isaat_af_type & ISAKMP_ATTR_RTYPE_MASK) < 32); if (LHAS(seen_attrs, a.isaat_af_type & ISAKMP_ATTR_RTYPE_MASK)) { loglog(RC_LOG_SERIOUS, "repeated %s attribute in Oakley Transform %u" , enum_show(&oakley_attr_names, a.isaat_af_type) , trans.isat_transnum); return BAD_PROPOSAL_SYNTAX; } seen_attrs |= LELEM(a.isaat_af_type & ISAKMP_ATTR_RTYPE_MASK); val = a.isaat_lv; DBG(DBG_PARSING, { enum_names *vdesc = oakley_attr_val_descs [a.isaat_af_type & ISAKMP_ATTR_RTYPE_MASK]; if (vdesc != NULL) { const char *nm = enum_name(vdesc, val); if (nm != NULL) DBG_log(" [%u is %s]", (unsigned)val, nm); } }); switch (a.isaat_af_type) { case OAKLEY_ENCRYPTION_ALGORITHM | ISAKMP_ATTR_AF_TV: if (ike_alg_enc_present(val)) { ta.encrypt = val; ta.encrypter = ike_alg_get_encrypter(val); ta.enckeylen = ta.encrypter->keydeflen; } else { ugh = builddiag("%s is not supported" , enum_show(&oakley_enc_names, val)); } break; case OAKLEY_HASH_ALGORITHM | ISAKMP_ATTR_AF_TV: if (ike_alg_hash_present(val)) { ta.hash = val; ta.hasher = ike_alg_get_hasher(val); } else { ugh = builddiag("%s is not supported" , enum_show(&oakley_hash_names, val)); } break; case OAKLEY_AUTHENTICATION_METHOD | ISAKMP_ATTR_AF_TV: { /* check that authentication method is acceptable */ lset_t iap = st->st_policy & POLICY_ID_AUTH_MASK; /* is the initiator the XAUTH client? */ bool xauth_init = ( initiator && (st->st_policy & POLICY_XAUTH_SERVER) == LEMPTY) || (!initiator && (st->st_policy & POLICY_XAUTH_SERVER) != LEMPTY); switch (val) { case OAKLEY_PRESHARED_KEY: if ((iap & POLICY_PSK) == LEMPTY) { ugh = "policy does not allow OAKLEY_PRESHARED_KEY authentication"; } else { ugh = find_preshared_key(st); ta.auth = OAKLEY_PRESHARED_KEY; } break; case XAUTHInitPreShared: if ((iap & POLICY_XAUTH_PSK) == LEMPTY || !xauth_init) { ugh = "policy does not allow XAUTHInitPreShared authentication"; } else { ugh = find_preshared_key(st); ta.auth = XAUTHInitPreShared; } break; case XAUTHRespPreShared: if ((iap & POLICY_XAUTH_PSK) == LEMPTY || xauth_init) { ugh = "policy does not allow XAUTHRespPreShared authentication"; } else { ugh = find_preshared_key(st); ta.auth = XAUTHRespPreShared; } break; case OAKLEY_RSA_SIG: /* Accept if policy specifies RSASIG or is default */ if ((iap & POLICY_RSASIG) == LEMPTY) { ugh = "policy does not allow OAKLEY_RSA_SIG authentication"; } else { ta.auth = OAKLEY_RSA_SIG; } break; case XAUTHInitRSA: if ((iap & POLICY_XAUTH_RSASIG) == LEMPTY || !xauth_init) { ugh = "policy does not allow XAUTHInitRSA authentication"; } else { ta.auth = XAUTHInitRSA; } break; case XAUTHRespRSA: if ((iap & POLICY_XAUTH_RSASIG) == LEMPTY || xauth_init) { ugh = "policy does not allow XAUTHRespRSA authentication"; } else { ta.auth = XAUTHRespRSA; } break; default: ugh = builddiag("Pluto does not support %s authentication" , enum_show(&oakley_auth_names, val)); break; } } break; case OAKLEY_GROUP_DESCRIPTION | ISAKMP_ATTR_AF_TV: ta.group = lookup_group(val); if (ta.group == NULL) { ugh = "only OAKLEY_GROUP_MODP1024 and OAKLEY_GROUP_MODP1536 supported"; } break; case OAKLEY_LIFE_TYPE | ISAKMP_ATTR_AF_TV: switch (val) { case OAKLEY_LIFE_SECONDS: case OAKLEY_LIFE_KILOBYTES: if (LHAS(seen_durations, val)) { loglog(RC_LOG_SERIOUS , "attribute OAKLEY_LIFE_TYPE value %s repeated" , enum_show(&oakley_lifetime_names, val)); return BAD_PROPOSAL_SYNTAX; } seen_durations |= LELEM(val); life_type = val; break; default: ugh = builddiag("unknown value %s" , enum_show(&oakley_lifetime_names, val)); break; } break; case OAKLEY_LIFE_DURATION | ISAKMP_ATTR_AF_TLV: val = decode_long_duration(&attr_pbs); /* fall through */ case OAKLEY_LIFE_DURATION | ISAKMP_ATTR_AF_TV: if (!LHAS(seen_attrs, OAKLEY_LIFE_TYPE)) { ugh = "OAKLEY_LIFE_DURATION attribute not preceded by OAKLEY_LIFE_TYPE attribute"; break; } seen_attrs &= ~(LELEM(OAKLEY_LIFE_DURATION) | LELEM(OAKLEY_LIFE_TYPE)); switch (life_type) { case OAKLEY_LIFE_SECONDS: if (val > OAKLEY_ISAKMP_SA_LIFETIME_MAXIMUM) { #ifdef CISCO_QUIRKS plog("peer requested %lu seconds" " which exceeds our limit %d seconds" , (long) val , OAKLEY_ISAKMP_SA_LIFETIME_MAXIMUM); plog("lifetime reduced to %d seconds " "(todo: IPSEC_RESPONDER_LIFETIME notification)" , OAKLEY_ISAKMP_SA_LIFETIME_MAXIMUM); val = OAKLEY_ISAKMP_SA_LIFETIME_MAXIMUM; #else ugh = builddiag("peer requested %lu seconds" " which exceeds our limit %d seconds" , (long) val , OAKLEY_ISAKMP_SA_LIFETIME_MAXIMUM); #endif } ta.life_seconds = val; break; case OAKLEY_LIFE_KILOBYTES: ta.life_kilobytes = val; break; default: bad_case(life_type); } break; case OAKLEY_KEY_LENGTH | ISAKMP_ATTR_AF_TV: if ((seen_attrs & LELEM(OAKLEY_ENCRYPTION_ALGORITHM)) == 0) { ugh = "OAKLEY_KEY_LENGTH attribute not preceded by " "OAKLEY_ENCRYPTION_ALGORITHM attribute"; break; } if (ta.encrypter == NULL) { ugh = "NULL encrypter with seen OAKLEY_ENCRYPTION_ALGORITHM"; break; } /* * check if this keylen is compatible with specified algorithm */ if (val && (val < ta.encrypter->keyminlen || val > ta.encrypter->keymaxlen)) { ugh = "peer proposed key length not valid for " "encryption algorithm specified"; } ta.enckeylen = val; break; #if 0 /* not yet supported */ case OAKLEY_GROUP_TYPE | ISAKMP_ATTR_AF_TV: case OAKLEY_PRF | ISAKMP_ATTR_AF_TV: case OAKLEY_FIELD_SIZE | ISAKMP_ATTR_AF_TV: case OAKLEY_GROUP_PRIME | ISAKMP_ATTR_AF_TV: case OAKLEY_GROUP_PRIME | ISAKMP_ATTR_AF_TLV: case OAKLEY_GROUP_GENERATOR_ONE | ISAKMP_ATTR_AF_TV: case OAKLEY_GROUP_GENERATOR_ONE | ISAKMP_ATTR_AF_TLV: case OAKLEY_GROUP_GENERATOR_TWO | ISAKMP_ATTR_AF_TV: case OAKLEY_GROUP_GENERATOR_TWO | ISAKMP_ATTR_AF_TLV: case OAKLEY_GROUP_CURVE_A | ISAKMP_ATTR_AF_TV: case OAKLEY_GROUP_CURVE_A | ISAKMP_ATTR_AF_TLV: case OAKLEY_GROUP_CURVE_B | ISAKMP_ATTR_AF_TV: case OAKLEY_GROUP_CURVE_B | ISAKMP_ATTR_AF_TLV: case OAKLEY_GROUP_ORDER | ISAKMP_ATTR_AF_TV: case OAKLEY_GROUP_ORDER | ISAKMP_ATTR_AF_TLV: #endif default: /* fix compiler warning */ memset(&ta, 0, sizeof(ta)); ugh = "unsupported OAKLEY attribute"; break; } if (ugh != NULL) { loglog(RC_LOG_SERIOUS, "%s. Attribute %s" , ugh, enum_show(&oakley_attr_names, a.isaat_af_type)); break; } } /* * ML: at last check for allowed transforms in alg_info_ike * (ALG_INFO_F_STRICT flag) */ if (ugh == NULL) { if (!ike_alg_ok_final(ta.encrypt, ta.enckeylen, ta.hash, ta.group ? ta.group->group : -1, c->alg_info_ike)) { ugh = "OAKLEY proposal refused"; } } if (ugh == NULL) { /* a little more checking is in order */ { lset_t missing = ~seen_attrs & (LELEM(OAKLEY_ENCRYPTION_ALGORITHM) | LELEM(OAKLEY_HASH_ALGORITHM) | LELEM(OAKLEY_AUTHENTICATION_METHOD) | LELEM(OAKLEY_GROUP_DESCRIPTION)); if (missing) { loglog(RC_LOG_SERIOUS, "missing mandatory attribute(s) %s in Oakley Transform %u" , bitnamesof(oakley_attr_bit_names, missing) , trans.isat_transnum); return BAD_PROPOSAL_SYNTAX; } } /* We must have liked this transform. * Lets finish early and leave. */ DBG(DBG_PARSING | DBG_CRYPT , DBG_log("Oakley Transform %u accepted", trans.isat_transnum)); if (r_sa_pbs != NULL) { struct isakmp_proposal r_proposal = *proposal; pb_stream r_proposal_pbs; struct isakmp_transform r_trans = trans; pb_stream r_trans_pbs; /* Situation */ if (!out_struct(&ipsecdoisit, &ipsec_sit_desc, r_sa_pbs, NULL)) impossible(); /* Proposal */ #ifdef EMIT_ISAKMP_SPI r_proposal.isap_spisize = COOKIE_SIZE; #else r_proposal.isap_spisize = 0; #endif r_proposal.isap_notrans = 1; if (!out_struct(&r_proposal, &isakmp_proposal_desc, r_sa_pbs, &r_proposal_pbs)) impossible(); /* SPI */ #ifdef EMIT_ISAKMP_SPI if (!out_raw(my_cookie, COOKIE_SIZE, &r_proposal_pbs, "SPI")) impossible(); r_proposal.isap_spisize = COOKIE_SIZE; #else /* none (0) */ #endif /* Transform */ r_trans.isat_np = ISAKMP_NEXT_NONE; if (!out_struct(&r_trans, &isakmp_isakmp_transform_desc, &r_proposal_pbs, &r_trans_pbs)) impossible(); if (!out_raw(attr_start, attr_len, &r_trans_pbs, "attributes")) impossible(); close_output_pbs(&r_trans_pbs); close_output_pbs(&r_proposal_pbs); close_output_pbs(r_sa_pbs); } /* copy over the results */ st->st_oakley = ta; return NOTHING_WRONG; } /* on to next transform */ no_trans_left--; if (trans.isat_np == ISAKMP_NEXT_NONE) { if (no_trans_left != 0) { loglog(RC_LOG_SERIOUS, "number of Transform Payloads disagrees with Oakley Proposal Payload"); return BAD_PROPOSAL_SYNTAX; } break; } if (trans.isat_np != ISAKMP_NEXT_T) { loglog(RC_LOG_SERIOUS, "unexpected %s payload in Oakley Proposal" , enum_show(&payload_names, proposal->isap_np)); return BAD_PROPOSAL_SYNTAX; } } loglog(RC_LOG_SERIOUS, "no acceptable Oakley Transform"); return NO_PROPOSAL_CHOSEN; } /* Parse the body of an IPsec SA Payload (i.e. Phase 2 / Quick Mode). * * The main routine is parse_ipsec_sa_body; other functions defined * between here and there are just helpers. * * Various shortcuts are taken. In particular, the policy, such as * it is, is hardwired. * * If r_sa is non-NULL, the body of an SA representing the selected * proposal is emitted into it. * * If "selection" is true, the SA is supposed to represent the * single tranform that the peer has accepted. * ??? We only check that it is acceptable, not that it is one that we offered! * * Only IPsec DOI is accepted (what is the ISAKMP DOI?). * Error response is rudimentary. * * Since all ISAKMP groups in all SA Payloads must match, st->st_pfs_group * holds this across multiple payloads. * &unset_group signifies not yet "set"; NULL signifies NONE. * * This routine is used by quick_inI1_outR1() and quick_inR1_outI2(). */ static const struct ipsec_trans_attrs null_ipsec_trans_attrs = { 0, /* transid (NULL, for now) */ 0, /* spi */ SA_LIFE_DURATION_DEFAULT, /* life_seconds */ SA_LIFE_DURATION_K_DEFAULT, /* life_kilobytes */ ENCAPSULATION_MODE_UNSPECIFIED, /* encapsulation */ AUTH_ALGORITHM_NONE, /* auth */ 0, /* key_len */ 0, /* key_rounds */ }; static bool parse_ipsec_transform(struct isakmp_transform *trans , struct ipsec_trans_attrs *attrs , pb_stream *prop_pbs , pb_stream *trans_pbs , struct_desc *trans_desc , int previous_transnum /* or -1 if none */ , bool selection , bool is_last , bool is_ipcomp , struct state *st) /* current state object */ { lset_t seen_attrs = 0; lset_t seen_durations = 0; u_int16_t life_type = 0; const struct oakley_group_desc *pfs_group = NULL; if (!in_struct(trans, trans_desc, prop_pbs, trans_pbs)) return FALSE; if (trans->isat_transnum <= previous_transnum) { loglog(RC_LOG_SERIOUS, "Transform Numbers in Proposal are not monotonically increasing"); return FALSE; } switch (trans->isat_np) { case ISAKMP_NEXT_T: if (is_last) { loglog(RC_LOG_SERIOUS, "Proposal Payload has more Transforms than specified"); return FALSE; } break; case ISAKMP_NEXT_NONE: if (!is_last) { loglog(RC_LOG_SERIOUS, "Proposal Payload has fewer Transforms than specified"); return FALSE; } break; default: loglog(RC_LOG_SERIOUS, "expecting Transform Payload, but found %s in Proposal" , enum_show(&payload_names, trans->isat_np)); return FALSE; } *attrs = null_ipsec_trans_attrs; attrs->transid = trans->isat_transid; while (pbs_left(trans_pbs) != 0) { struct isakmp_attribute a; pb_stream attr_pbs; enum_names *vdesc; u_int32_t val; /* room for larger value */ bool ipcomp_inappropriate = is_ipcomp; /* will get reset if OK */ if (!in_struct(&a, &isakmp_ipsec_attribute_desc, trans_pbs, &attr_pbs)) return FALSE; passert((a.isaat_af_type & ISAKMP_ATTR_RTYPE_MASK) < 32); if (LHAS(seen_attrs, a.isaat_af_type & ISAKMP_ATTR_RTYPE_MASK)) { loglog(RC_LOG_SERIOUS, "repeated %s attribute in IPsec Transform %u" , enum_show(&ipsec_attr_names, a.isaat_af_type) , trans->isat_transnum); return FALSE; } seen_attrs |= LELEM(a.isaat_af_type & ISAKMP_ATTR_RTYPE_MASK); val = a.isaat_lv; vdesc = ipsec_attr_val_descs[a.isaat_af_type & ISAKMP_ATTR_RTYPE_MASK]; if (vdesc != NULL) { if (enum_name(vdesc, val) == NULL) { loglog(RC_LOG_SERIOUS, "invalid value %u for attribute %s in IPsec Transform" , (unsigned)val, enum_show(&ipsec_attr_names, a.isaat_af_type)); return FALSE; } DBG(DBG_PARSING , if ((a.isaat_af_type & ISAKMP_ATTR_AF_MASK) == ISAKMP_ATTR_AF_TV) DBG_log(" [%u is %s]" , (unsigned)val, enum_show(vdesc, val))); } switch (a.isaat_af_type) { case SA_LIFE_TYPE | ISAKMP_ATTR_AF_TV: ipcomp_inappropriate = FALSE; if (LHAS(seen_durations, val)) { loglog(RC_LOG_SERIOUS, "attribute SA_LIFE_TYPE value %s repeated in message" , enum_show(&sa_lifetime_names, val)); return FALSE; } seen_durations |= LELEM(val); life_type = val; break; case SA_LIFE_DURATION | ISAKMP_ATTR_AF_TLV: val = decode_long_duration(&attr_pbs); /* fall through */ case SA_LIFE_DURATION | ISAKMP_ATTR_AF_TV: ipcomp_inappropriate = FALSE; if (!LHAS(seen_attrs, SA_LIFE_DURATION)) { loglog(RC_LOG_SERIOUS, "SA_LIFE_DURATION IPsec attribute not preceded by SA_LIFE_TYPE attribute"); return FALSE; } seen_attrs &= ~(LELEM(SA_LIFE_DURATION) | LELEM(SA_LIFE_TYPE)); switch (life_type) { case SA_LIFE_TYPE_SECONDS: /* silently limit duration to our maximum */ attrs->life_seconds = val <= SA_LIFE_DURATION_MAXIMUM ? val : SA_LIFE_DURATION_MAXIMUM; break; case SA_LIFE_TYPE_KBYTES: attrs->life_kilobytes = val; break; default: bad_case(life_type); } break; case GROUP_DESCRIPTION | ISAKMP_ATTR_AF_TV: if (is_ipcomp) { /* Accept reluctantly. Should not happen, according to * draft-shacham-ippcp-rfc2393bis-05.txt 4.1. */ ipcomp_inappropriate = FALSE; loglog(RC_COMMENT , "IPCA (IPcomp SA) contains GROUP_DESCRIPTION." " Ignoring inapproprate attribute."); } pfs_group = lookup_group(val); if (pfs_group == NULL) { loglog(RC_LOG_SERIOUS, "only OAKLEY_GROUP_MODP1024 and OAKLEY_GROUP_MODP1536 supported for PFS"); return FALSE; } break; case ENCAPSULATION_MODE | ISAKMP_ATTR_AF_TV: ipcomp_inappropriate = FALSE; switch (val) { case ENCAPSULATION_MODE_TUNNEL: case ENCAPSULATION_MODE_TRANSPORT: if (st->nat_traversal & NAT_T_DETECTED) { loglog(RC_LOG_SERIOUS , "%s must only be used if NAT-Traversal is not detected" , enum_name(&enc_mode_names, val)); /* * Accept it anyway because SSH-Sentinel does not * use UDP_TUNNEL or UDP_TRANSPORT for the diagnostic. * * remove when SSH-Sentinel is fixed */ #ifdef I_DONT_CARE_OF_SSH_SENTINEL return FALSE; #endif } attrs->encapsulation = val; break; case ENCAPSULATION_MODE_UDP_TRANSPORT_DRAFTS: #ifndef I_KNOW_TRANSPORT_MODE_HAS_SECURITY_CONCERN_BUT_I_WANT_IT loglog(RC_LOG_SERIOUS , "NAT-Traversal: Transport mode disabled due to security concerns"); return FALSE; #endif case ENCAPSULATION_MODE_UDP_TUNNEL_DRAFTS: if (st->nat_traversal & NAT_T_WITH_RFC_VALUES) { loglog(RC_LOG_SERIOUS , "%s must only be used with old IETF drafts" , enum_name(&enc_mode_names, val)); return FALSE; } else if (st->nat_traversal & NAT_T_DETECTED) { attrs->encapsulation = val - ENCAPSULATION_MODE_UDP_TUNNEL_DRAFTS + ENCAPSULATION_MODE_TUNNEL; } else { loglog(RC_LOG_SERIOUS , "%s must only be used if NAT-Traversal is detected" , enum_name(&enc_mode_names, val)); return FALSE; } break; case ENCAPSULATION_MODE_UDP_TRANSPORT_RFC: #ifndef I_KNOW_TRANSPORT_MODE_HAS_SECURITY_CONCERN_BUT_I_WANT_IT loglog(RC_LOG_SERIOUS , "NAT-Traversal: Transport mode disabled due " "to security concerns"); return FALSE; #endif case ENCAPSULATION_MODE_UDP_TUNNEL_RFC: if ((st->nat_traversal & NAT_T_DETECTED) && (st->nat_traversal & NAT_T_WITH_RFC_VALUES)) { attrs->encapsulation = val - ENCAPSULATION_MODE_UDP_TUNNEL_RFC + ENCAPSULATION_MODE_TUNNEL; } else if (st->nat_traversal & NAT_T_DETECTED) { loglog(RC_LOG_SERIOUS , "%s must only be used with NAT-T RFC" , enum_name(&enc_mode_names, val)); return FALSE; } else { loglog(RC_LOG_SERIOUS , "%s must only be used if NAT-Traversal is detected" , enum_name(&enc_mode_names, val)); return FALSE; } break; default: loglog(RC_LOG_SERIOUS , "unknown ENCAPSULATION_MODE %d in IPSec SA", val); return FALSE; } break; case AUTH_ALGORITHM | ISAKMP_ATTR_AF_TV: attrs->auth = val; break; case KEY_LENGTH | ISAKMP_ATTR_AF_TV: attrs->key_len = val; break; case KEY_ROUNDS | ISAKMP_ATTR_AF_TV: attrs->key_rounds = val; break; #if 0 /* not yet implemented */ case COMPRESS_DICT_SIZE | ISAKMP_ATTR_AF_TV: break; case COMPRESS_PRIVATE_ALG | ISAKMP_ATTR_AF_TV: break; case SA_LIFE_DURATION | ISAKMP_ATTR_AF_TLV: break; case COMPRESS_PRIVATE_ALG | ISAKMP_ATTR_AF_TLV: break; #endif default: loglog(RC_LOG_SERIOUS, "unsupported IPsec attribute %s" , enum_show(&ipsec_attr_names, a.isaat_af_type)); return FALSE; } if (ipcomp_inappropriate) { loglog(RC_LOG_SERIOUS, "IPsec attribute %s inappropriate for IPCOMP" , enum_show(&ipsec_attr_names, a.isaat_af_type)); return FALSE; } } /* Although an IPCOMP SA (IPCA) ought not to have a pfs_group, * if it does, demand that it be consistent. * See draft-shacham-ippcp-rfc2393bis-05.txt 4.1. */ if (!is_ipcomp || pfs_group != NULL) { if (st->st_pfs_group == &unset_group) st->st_pfs_group = pfs_group; if (st->st_pfs_group != pfs_group) { loglog(RC_LOG_SERIOUS, "GROUP_DESCRIPTION inconsistent with that of %s in IPsec SA" , selection? "the Proposal" : "a previous Transform"); return FALSE; } } if (LHAS(seen_attrs, SA_LIFE_DURATION)) { loglog(RC_LOG_SERIOUS, "SA_LIFE_TYPE IPsec attribute not followed by SA_LIFE_DURATION attribute in message"); return FALSE; } if (!LHAS(seen_attrs, ENCAPSULATION_MODE)) { if (is_ipcomp) { /* draft-shacham-ippcp-rfc2393bis-05.txt 4.1: * "If the Encapsulation Mode is unspecified, * the default value of Transport Mode is assumed." * This contradicts/overrides the DOI (quuoted below). */ attrs->encapsulation = ENCAPSULATION_MODE_TRANSPORT; } else { /* ??? Technically, RFC 2407 (IPSEC DOI) 4.5 specifies that * the default is "unspecified (host-dependent)". * This makes little sense, so we demand that it be specified. */ loglog(RC_LOG_SERIOUS, "IPsec Transform must specify ENCAPSULATION_MODE"); return FALSE; } } /* ??? should check for key_len and/or key_rounds if required */ return TRUE; } static void echo_proposal( struct isakmp_proposal r_proposal, /* proposal to emit */ struct isakmp_transform r_trans, /* winning transformation within it */ u_int8_t np, /* Next Payload for proposal */ pb_stream *r_sa_pbs, /* SA PBS into which to emit */ struct ipsec_proto_info *pi, /* info about this protocol instance */ struct_desc *trans_desc, /* descriptor for this transformation */ pb_stream *trans_pbs, /* PBS for incoming transform */ struct spd_route *sr, /* host details for the association */ bool tunnel_mode) /* true for inner most tunnel SA */ { pb_stream r_proposal_pbs; pb_stream r_trans_pbs; /* Proposal */ r_proposal.isap_np = np; r_proposal.isap_notrans = 1; if (!out_struct(&r_proposal, &isakmp_proposal_desc, r_sa_pbs, &r_proposal_pbs)) impossible(); /* allocate and emit our CPI/SPI */ if (r_proposal.isap_protoid == PROTO_IPCOMP) { /* CPI is stored in network low order end of an * ipsec_spi_t. So we start a couple of bytes in. * Note: we may fail to generate a satisfactory CPI, * but we'll ignore that. */ pi->our_spi = get_my_cpi(sr, tunnel_mode); out_raw((u_char *) &pi->our_spi + IPSEC_DOI_SPI_SIZE - IPCOMP_CPI_SIZE , IPCOMP_CPI_SIZE , &r_proposal_pbs, "CPI"); } else { pi->our_spi = get_ipsec_spi(pi->attrs.spi , r_proposal.isap_protoid == PROTO_IPSEC_AH ? IPPROTO_AH : IPPROTO_ESP , sr , tunnel_mode); /* XXX should check for errors */ out_raw((u_char *) &pi->our_spi, IPSEC_DOI_SPI_SIZE , &r_proposal_pbs, "SPI"); } /* Transform */ r_trans.isat_np = ISAKMP_NEXT_NONE; if (!out_struct(&r_trans, trans_desc, &r_proposal_pbs, &r_trans_pbs)) impossible(); /* Transform Attributes: pure echo */ trans_pbs->cur = trans_pbs->start + sizeof(struct isakmp_transform); if (!out_raw(trans_pbs->cur, pbs_left(trans_pbs) , &r_trans_pbs, "attributes")) impossible(); close_output_pbs(&r_trans_pbs); close_output_pbs(&r_proposal_pbs); } notification_t parse_ipsec_sa_body( pb_stream *sa_pbs, /* body of input SA Payload */ const struct isakmp_sa *sa, /* header of input SA Payload */ pb_stream *r_sa_pbs, /* if non-NULL, where to emit body of winning SA */ bool selection, /* if this SA is a selection, only one transform may appear */ struct state *st) /* current state object */ { const struct connection *c = st->st_connection; u_int32_t ipsecdoisit; pb_stream next_proposal_pbs; struct isakmp_proposal next_proposal; ipsec_spi_t next_spi; bool next_full = TRUE; /* DOI */ if (sa->isasa_doi != ISAKMP_DOI_IPSEC) { loglog(RC_LOG_SERIOUS, "Unknown or unsupported DOI %s", enum_show(&doi_names, sa->isasa_doi)); /* XXX Could send notification back */ return DOI_NOT_SUPPORTED; } /* Situation */ if (!in_struct(&ipsecdoisit, &ipsec_sit_desc, sa_pbs, NULL)) return SITUATION_NOT_SUPPORTED; if (ipsecdoisit != SIT_IDENTITY_ONLY) { loglog(RC_LOG_SERIOUS, "unsupported IPsec DOI situation (%s)" , bitnamesof(sit_bit_names, ipsecdoisit)); /* XXX Could send notification back */ return SITUATION_NOT_SUPPORTED; } /* The rules for IPsec SAs are scattered. * RFC 2408 "ISAKMP" section 4.2 gives some info. * There may be multiple proposals. Those with identical proposal * numbers must be considered as conjuncts. Those with different * numbers are disjuncts. * Each proposal may have several transforms, each considered * an alternative. * Each transform may have several attributes, all applying. * * To handle the way proposals are combined, we need to do a * look-ahead. */ if (!in_struct(&next_proposal, &isakmp_proposal_desc, sa_pbs, &next_proposal_pbs)) return BAD_PROPOSAL_SYNTAX; /* for each conjunction of proposals... */ while (next_full) { int propno = next_proposal.isap_proposal; pb_stream ah_prop_pbs, esp_prop_pbs, ipcomp_prop_pbs; struct isakmp_proposal ah_proposal = {0, 0, 0, 0, 0, 0, 0}; struct isakmp_proposal esp_proposal = {0, 0, 0, 0, 0, 0, 0}; struct isakmp_proposal ipcomp_proposal = {0, 0, 0, 0, 0, 0, 0}; ipsec_spi_t ah_spi = 0; ipsec_spi_t esp_spi = 0; ipsec_spi_t ipcomp_cpi = 0; bool ah_seen = FALSE; bool esp_seen = FALSE; bool ipcomp_seen = FALSE; bool tunnel_mode = FALSE; int inner_proto = 0; u_int16_t well_known_cpi = 0; pb_stream ah_trans_pbs, esp_trans_pbs, ipcomp_trans_pbs; struct isakmp_transform ah_trans, esp_trans, ipcomp_trans; struct ipsec_trans_attrs ah_attrs, esp_attrs, ipcomp_attrs; /* for each proposal in the conjunction */ do { if (next_proposal.isap_protoid == PROTO_IPCOMP) { /* IPCOMP CPI */ if (next_proposal.isap_spisize == IPSEC_DOI_SPI_SIZE) { /* This code is to accommodate those peculiar * implementations that send a CPI in the bottom of an * SPI-sized field. * See draft-shacham-ippcp-rfc2393bis-05.txt 4.1 */ u_int8_t filler[IPSEC_DOI_SPI_SIZE - IPCOMP_CPI_SIZE]; if (!in_raw(filler, sizeof(filler) , &next_proposal_pbs, "CPI filler") || !all_zero(filler, sizeof(filler))) return INVALID_SPI; } else if (next_proposal.isap_spisize != IPCOMP_CPI_SIZE) { loglog(RC_LOG_SERIOUS, "IPsec Proposal with improper CPI size (%u)" , next_proposal.isap_spisize); return INVALID_SPI; } /* We store CPI in the low order of a network order * ipsec_spi_t. So we start a couple of bytes in. */ zero(&next_spi); if (!in_raw((u_char *)&next_spi + IPSEC_DOI_SPI_SIZE - IPCOMP_CPI_SIZE , IPCOMP_CPI_SIZE, &next_proposal_pbs, "CPI")) return INVALID_SPI; /* If sanity ruled, CPIs would have to be such that * the SAID (the triple (CPI, IPCOM, destination IP)) * would be unique, just like for SPIs. But there is a * perversion where CPIs can be well-known and consequently * the triple is not unique. We hide this fact from * ourselves by fudging the top 16 bits to make * the property true internally! */ switch (ntohl(next_spi)) { case IPCOMP_DEFLATE: well_known_cpi = ntohl(next_spi); next_spi = uniquify_his_cpi(next_spi, st); if (next_spi == 0) { loglog(RC_LOG_SERIOUS , "IPsec Proposal contains well-known CPI that I cannot uniquify"); return INVALID_SPI; } break; default: if (ntohl(next_spi) < IPCOMP_FIRST_NEGOTIATED || ntohl(next_spi) > IPCOMP_LAST_NEGOTIATED) { loglog(RC_LOG_SERIOUS, "IPsec Proposal contains CPI from non-negotiated range (0x%lx)" , (unsigned long) ntohl(next_spi)); return INVALID_SPI; } break; } } else { /* AH or ESP SPI */ if (next_proposal.isap_spisize != IPSEC_DOI_SPI_SIZE) { loglog(RC_LOG_SERIOUS, "IPsec Proposal with improper SPI size (%u)" , next_proposal.isap_spisize); return INVALID_SPI; } if (!in_raw((u_char *)&next_spi, sizeof(next_spi), &next_proposal_pbs, "SPI")) return INVALID_SPI; /* SPI value 0 is invalid and values 1-255 are reserved to IANA. * RFC 2402 (ESP) 2.4, RFC 2406 (AH) 2.1 * IPCOMP??? */ if (ntohl(next_spi) < IPSEC_DOI_SPI_MIN) { loglog(RC_LOG_SERIOUS, "IPsec Proposal contains invalid SPI (0x%lx)" , (unsigned long) ntohl(next_spi)); return INVALID_SPI; } } if (next_proposal.isap_notrans == 0) { loglog(RC_LOG_SERIOUS, "IPsec Proposal contains no Transforms"); return BAD_PROPOSAL_SYNTAX; } switch (next_proposal.isap_protoid) { case PROTO_IPSEC_AH: if (ah_seen) { loglog(RC_LOG_SERIOUS, "IPsec SA contains two simultaneous AH Proposals"); return BAD_PROPOSAL_SYNTAX; } ah_seen = TRUE; ah_prop_pbs = next_proposal_pbs; ah_proposal = next_proposal; ah_spi = next_spi; break; case PROTO_IPSEC_ESP: if (esp_seen) { loglog(RC_LOG_SERIOUS, "IPsec SA contains two simultaneous ESP Proposals"); return BAD_PROPOSAL_SYNTAX; } esp_seen = TRUE; esp_prop_pbs = next_proposal_pbs; esp_proposal = next_proposal; esp_spi = next_spi; break; case PROTO_IPCOMP: if (ipcomp_seen) { loglog(RC_LOG_SERIOUS, "IPsec SA contains two simultaneous IPCOMP Proposals"); return BAD_PROPOSAL_SYNTAX; } ipcomp_seen = TRUE; ipcomp_prop_pbs = next_proposal_pbs; ipcomp_proposal = next_proposal; ipcomp_cpi = next_spi; break; default: loglog(RC_LOG_SERIOUS, "unexpected Protocol ID (%s) in IPsec Proposal" , enum_show(&protocol_names, next_proposal.isap_protoid)); return INVALID_PROTOCOL_ID; } /* refill next_proposal */ if (next_proposal.isap_np == ISAKMP_NEXT_NONE) { next_full = FALSE; break; } else if (next_proposal.isap_np != ISAKMP_NEXT_P) { loglog(RC_LOG_SERIOUS, "unexpected in Proposal: %s" , enum_show(&payload_names, next_proposal.isap_np)); return BAD_PROPOSAL_SYNTAX; } if (!in_struct(&next_proposal, &isakmp_proposal_desc, sa_pbs, &next_proposal_pbs)) return BAD_PROPOSAL_SYNTAX; } while (next_proposal.isap_proposal == propno); /* Now that we have all conjuncts, we should try * the Cartesian product of eachs tranforms! * At the moment, we take short-cuts on account of * our rudimentary hard-wired policy. * For now, we find an acceptable AH (if any) * and then an acceptable ESP. The only interaction * is that the ESP acceptance can know whether there * was an acceptable AH and hence not require an AUTH. */ if (ah_seen) { int previous_transnum = -1; int tn; for (tn = 0; tn != ah_proposal.isap_notrans; tn++) { int ok_transid = 0; bool ok_auth = FALSE; if (!parse_ipsec_transform(&ah_trans , &ah_attrs , &ah_prop_pbs , &ah_trans_pbs , &isakmp_ah_transform_desc , previous_transnum , selection , tn == ah_proposal.isap_notrans - 1 , FALSE , st)) return BAD_PROPOSAL_SYNTAX; previous_transnum = ah_trans.isat_transnum; /* we must understand ah_attrs.transid * COMBINED with ah_attrs.auth. * See RFC 2407 "IPsec DOI" section 4.4.3 * The following combinations are legal, * but we don't implement all of them: * It seems as if each auth algorithm * only applies to one ah transid. * AH_MD5, AUTH_ALGORITHM_HMAC_MD5 * AH_MD5, AUTH_ALGORITHM_KPDK (unimplemented) * AH_SHA, AUTH_ALGORITHM_HMAC_SHA1 * AH_DES, AUTH_ALGORITHM_DES_MAC (unimplemented) */ switch (ah_attrs.auth) { case AUTH_ALGORITHM_NONE: loglog(RC_LOG_SERIOUS, "AUTH_ALGORITHM attribute missing in AH Transform"); return BAD_PROPOSAL_SYNTAX; case AUTH_ALGORITHM_HMAC_MD5: ok_auth = TRUE; /* fall through */ case AUTH_ALGORITHM_KPDK: ok_transid = AH_MD5; break; case AUTH_ALGORITHM_HMAC_SHA1: ok_auth = TRUE; ok_transid = AH_SHA; break; case AUTH_ALGORITHM_DES_MAC: ok_transid = AH_DES; break; } if (ah_attrs.transid != ok_transid) { loglog(RC_LOG_SERIOUS, "%s attribute inappropriate in %s Transform" , enum_name(&auth_alg_names, ah_attrs.auth) , enum_show(&ah_transformid_names, ah_attrs.transid)); return BAD_PROPOSAL_SYNTAX; } if (!ok_auth) { DBG(DBG_CONTROL | DBG_CRYPT , DBG_log("%s attribute unsupported" " in %s Transform from %s" , enum_name(&auth_alg_names, ah_attrs.auth) , enum_show(&ah_transformid_names, ah_attrs.transid) , ip_str(&c->spd.that.host_addr))); continue; /* try another */ } break; /* we seem to be happy */ } if (tn == ah_proposal.isap_notrans) continue; /* we didn't find a nice one */ ah_attrs.spi = ah_spi; inner_proto = IPPROTO_AH; if (ah_attrs.encapsulation == ENCAPSULATION_MODE_TUNNEL) tunnel_mode = TRUE; } if (esp_seen) { int previous_transnum = -1; int tn; for (tn = 0; tn != esp_proposal.isap_notrans; tn++) { if (!parse_ipsec_transform(&esp_trans , &esp_attrs , &esp_prop_pbs , &esp_trans_pbs , &isakmp_esp_transform_desc , previous_transnum , selection , tn == esp_proposal.isap_notrans - 1 , FALSE , st)) return BAD_PROPOSAL_SYNTAX; previous_transnum = esp_trans.isat_transnum; /* set default key length for AES encryption */ if (!esp_attrs.key_len && esp_attrs.transid == ESP_AES) { esp_attrs.key_len = 128; /* bits */ } if (!kernel_alg_esp_enc_ok(esp_attrs.transid, esp_attrs.key_len ,c->alg_info_esp)) { switch (esp_attrs.transid) { case ESP_3DES: break; #ifdef SUPPORT_ESP_NULL /* should be about as secure as AH-only */ case ESP_NULL: if (esp_attrs.auth == AUTH_ALGORITHM_NONE) { loglog(RC_LOG_SERIOUS, "ESP_NULL requires auth algorithm"); return BAD_PROPOSAL_SYNTAX; } if (st->st_policy & POLICY_ENCRYPT) { DBG(DBG_CONTROL | DBG_CRYPT , DBG_log("ESP_NULL Transform Proposal from %s" " does not satisfy POLICY_ENCRYPT" , ip_str(&c->spd.that.host_addr))); continue; /* try another */ } break; #endif default: DBG(DBG_CONTROL | DBG_CRYPT , DBG_log("unsupported ESP Transform %s from %s" , enum_show(&esp_transformid_names, esp_attrs.transid) , ip_str(&c->spd.that.host_addr))); continue; /* try another */ } } if (!kernel_alg_esp_auth_ok(esp_attrs.auth, c->alg_info_esp)) { switch (esp_attrs.auth) { case AUTH_ALGORITHM_NONE: if (!ah_seen) { DBG(DBG_CONTROL | DBG_CRYPT , DBG_log("ESP from %s must either have AUTH or be combined with AH" , ip_str(&c->spd.that.host_addr))); continue; /* try another */ } break; case AUTH_ALGORITHM_HMAC_MD5: case AUTH_ALGORITHM_HMAC_SHA1: break; default: DBG(DBG_CONTROL | DBG_CRYPT , DBG_log("unsupported ESP auth alg %s from %s" , enum_show(&auth_alg_names, esp_attrs.auth) , ip_str(&c->spd.that.host_addr))); continue; /* try another */ } } /* A last check for allowed transforms in alg_info_esp * (ALG_INFO_F_STRICT flag) */ if (!kernel_alg_esp_ok_final(esp_attrs.transid, esp_attrs.key_len ,esp_attrs.auth, c->alg_info_esp)) { continue; } if (ah_seen && ah_attrs.encapsulation != esp_attrs.encapsulation) { /* ??? This should be an error, but is it? */ DBG(DBG_CONTROL | DBG_CRYPT , DBG_log("AH and ESP transforms disagree about encapsulation; TUNNEL presumed")); } break; /* we seem to be happy */ } if (tn == esp_proposal.isap_notrans) continue; /* we didn't find a nice one */ esp_attrs.spi = esp_spi; inner_proto = IPPROTO_ESP; if (esp_attrs.encapsulation == ENCAPSULATION_MODE_TUNNEL) tunnel_mode = TRUE; } else if (st->st_policy & POLICY_ENCRYPT) { DBG(DBG_CONTROL | DBG_CRYPT , DBG_log("policy for \"%s\" requires encryption but ESP not in Proposal from %s" , c->name, ip_str(&c->spd.that.host_addr))); continue; /* we needed encryption, but didn't find ESP */ } else if ((st->st_policy & POLICY_AUTHENTICATE) && !ah_seen) { DBG(DBG_CONTROL | DBG_CRYPT , DBG_log("policy for \"%s\" requires authentication" " but none in Proposal from %s" , c->name, ip_str(&c->spd.that.host_addr))); continue; /* we need authentication, but we found neither ESP nor AH */ } if (ipcomp_seen) { int previous_transnum = -1; int tn; #ifdef NEVER /* we think IPcomp is working now */ /**** FUDGE TO PREVENT UNREQUESTED IPCOMP: **** NEEDED BECAUSE OUR IPCOMP IS EXPERIMENTAL (UNSTABLE). ****/ if (!(st->st_policy & POLICY_COMPRESS)) { plog("compression proposed by %s, but policy for \"%s\" forbids it" , ip_str(&c->spd.that.host_addr), c->name); continue; /* unwanted compression proposal */ } #endif if (!can_do_IPcomp) { plog("compression proposed by %s, but KLIPS is not configured with IPCOMP" , ip_str(&c->spd.that.host_addr)); continue; } if (well_known_cpi != 0 && !ah_seen && !esp_seen) { plog("illegal proposal: bare IPCOMP used with well-known CPI"); return BAD_PROPOSAL_SYNTAX; } for (tn = 0; tn != ipcomp_proposal.isap_notrans; tn++) { if (!parse_ipsec_transform(&ipcomp_trans , &ipcomp_attrs , &ipcomp_prop_pbs , &ipcomp_trans_pbs , &isakmp_ipcomp_transform_desc , previous_transnum , selection , tn == ipcomp_proposal.isap_notrans - 1 , TRUE , st)) return BAD_PROPOSAL_SYNTAX; previous_transnum = ipcomp_trans.isat_transnum; if (well_known_cpi != 0 && ipcomp_attrs.transid != well_known_cpi) { plog("illegal proposal: IPCOMP well-known CPI disagrees with transform"); return BAD_PROPOSAL_SYNTAX; } switch (ipcomp_attrs.transid) { case IPCOMP_DEFLATE: /* all we can handle! */ break; default: DBG(DBG_CONTROL | DBG_CRYPT , DBG_log("unsupported IPCOMP Transform %s from %s" , enum_show(&ipcomp_transformid_names, ipcomp_attrs.transid) , ip_str(&c->spd.that.host_addr))); continue; /* try another */ } if (ah_seen && ah_attrs.encapsulation != ipcomp_attrs.encapsulation) { /* ??? This should be an error, but is it? */ DBG(DBG_CONTROL | DBG_CRYPT , DBG_log("AH and IPCOMP transforms disagree about encapsulation; TUNNEL presumed")); } else if (esp_seen && esp_attrs.encapsulation != ipcomp_attrs.encapsulation) { /* ??? This should be an error, but is it? */ DBG(DBG_CONTROL | DBG_CRYPT , DBG_log("ESP and IPCOMP transforms disagree about encapsulation; TUNNEL presumed")); } break; /* we seem to be happy */ } if (tn == ipcomp_proposal.isap_notrans) continue; /* we didn't find a nice one */ ipcomp_attrs.spi = ipcomp_cpi; inner_proto = IPPROTO_COMP; if (ipcomp_attrs.encapsulation == ENCAPSULATION_MODE_TUNNEL) tunnel_mode = TRUE; } /* Eureka: we liked what we saw -- accept it. */ if (r_sa_pbs != NULL) { /* emit what we've accepted */ /* Situation */ if (!out_struct(&ipsecdoisit, &ipsec_sit_desc, r_sa_pbs, NULL)) impossible(); /* AH proposal */ if (ah_seen) echo_proposal(ah_proposal , ah_trans , esp_seen || ipcomp_seen? ISAKMP_NEXT_P : ISAKMP_NEXT_NONE , r_sa_pbs , &st->st_ah , &isakmp_ah_transform_desc , &ah_trans_pbs , &st->st_connection->spd , tunnel_mode && inner_proto == IPPROTO_AH); /* ESP proposal */ if (esp_seen) echo_proposal(esp_proposal , esp_trans , ipcomp_seen? ISAKMP_NEXT_P : ISAKMP_NEXT_NONE , r_sa_pbs , &st->st_esp , &isakmp_esp_transform_desc , &esp_trans_pbs , &st->st_connection->spd , tunnel_mode && inner_proto == IPPROTO_ESP); /* IPCOMP proposal */ if (ipcomp_seen) echo_proposal(ipcomp_proposal , ipcomp_trans , ISAKMP_NEXT_NONE , r_sa_pbs , &st->st_ipcomp , &isakmp_ipcomp_transform_desc , &ipcomp_trans_pbs , &st->st_connection->spd , tunnel_mode && inner_proto == IPPROTO_COMP); close_output_pbs(r_sa_pbs); } /* save decoded version of winning SA in state */ st->st_ah.present = ah_seen; if (ah_seen) st->st_ah.attrs = ah_attrs; st->st_esp.present = esp_seen; if (esp_seen) st->st_esp.attrs = esp_attrs; st->st_ipcomp.present = ipcomp_seen; if (ipcomp_seen) st->st_ipcomp.attrs = ipcomp_attrs; return NOTHING_WRONG; } loglog(RC_LOG_SERIOUS, "no acceptable Proposal in IPsec SA"); return NO_PROPOSAL_CHOSEN; }