/* $NetBSD: ip_ipsec_pxy.c,v 1.3 2012/07/22 14:27:51 darrenr Exp $ */ /* * Copyright (C) 2012 by Darren Reed. * * See the IPFILTER.LICENCE file for details on licencing. * * Simple ISAKMP transparent proxy for in-kernel use. For use with the NAT * code. * * Id: ip_ipsec_pxy.c,v 1.1.1.2 2012/07/22 13:45:19 darrenr Exp * */ #include __KERNEL_RCSID(1, "$NetBSD: ip_ipsec_pxy.c,v 1.3 2012/07/22 14:27:51 darrenr Exp $"); #define IPF_IPSEC_PROXY /* * IPSec proxy */ typedef struct ipf_ipsec_softc_s { frentry_t ipsec_fr; int ipsec_proxy_init; int ipsec_proxy_ttl; ipftq_t *ipsec_nat_tqe; ipftq_t *ipsec_state_tqe; char ipsec_buffer[1500]; } ipf_ipsec_softc_t; void *ipf_p_ipsec_soft_create(ipf_main_softc_t *); void ipf_p_ipsec_soft_destroy(ipf_main_softc_t *, void *); int ipf_p_ipsec_soft_init(ipf_main_softc_t *, void *); void ipf_p_ipsec_soft_fini(ipf_main_softc_t *, void *); int ipf_p_ipsec_init(void); void ipf_p_ipsec_fini(void); int ipf_p_ipsec_new(void *, fr_info_t *, ap_session_t *, nat_t *); void ipf_p_ipsec_del(ipf_main_softc_t *, ap_session_t *); int ipf_p_ipsec_inout(void *, fr_info_t *, ap_session_t *, nat_t *); int ipf_p_ipsec_match(fr_info_t *, ap_session_t *, nat_t *); /* * IPSec application proxy initialization. */ void * ipf_p_ipsec_soft_create(ipf_main_softc_t *softc) { ipf_ipsec_softc_t *softi; KMALLOC(softi, ipf_ipsec_softc_t *); if (softi == NULL) return NULL; bzero((char *)softi, sizeof(*softi)); softi->ipsec_fr.fr_ref = 1; softi->ipsec_fr.fr_flags = FR_OUTQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE; MUTEX_INIT(&softi->ipsec_fr.fr_lock, "IPsec proxy rule lock"); softi->ipsec_proxy_init = 1; softi->ipsec_proxy_ttl = 60; return softi; } int ipf_p_ipsec_soft_init(ipf_main_softc_t *softc, void *arg) { ipf_ipsec_softc_t *softi = arg; softi->ipsec_nat_tqe = ipf_state_add_tq(softc, softi->ipsec_proxy_ttl); if (softi->ipsec_nat_tqe == NULL) return -1; softi->ipsec_state_tqe = ipf_nat_add_tq(softc, softi->ipsec_proxy_ttl); if (softi->ipsec_state_tqe == NULL) { if (ipf_deletetimeoutqueue(softi->ipsec_nat_tqe) == 0) ipf_freetimeoutqueue(softc, softi->ipsec_nat_tqe); softi->ipsec_nat_tqe = NULL; return -1; } softi->ipsec_nat_tqe->ifq_flags |= IFQF_PROXY; softi->ipsec_state_tqe->ifq_flags |= IFQF_PROXY; softi->ipsec_fr.fr_age[0] = softi->ipsec_proxy_ttl; softi->ipsec_fr.fr_age[1] = softi->ipsec_proxy_ttl; return 0; } void ipf_p_ipsec_soft_fini(ipf_main_softc_t *softc, void *arg) { ipf_ipsec_softc_t *softi = arg; if (arg == NULL) return; if (softi->ipsec_nat_tqe != NULL) { if (ipf_deletetimeoutqueue(softi->ipsec_nat_tqe) == 0) ipf_freetimeoutqueue(softc, softi->ipsec_nat_tqe); } softi->ipsec_nat_tqe = NULL; if (softi->ipsec_state_tqe != NULL) { if (ipf_deletetimeoutqueue(softi->ipsec_state_tqe) == 0) ipf_freetimeoutqueue(softc, softi->ipsec_state_tqe); } softi->ipsec_state_tqe = NULL; } void ipf_p_ipsec_soft_destroy(ipf_main_softc_t *softc, void *arg) { ipf_ipsec_softc_t *softi = arg; if (softi->ipsec_proxy_init == 1) { MUTEX_DESTROY(&softi->ipsec_fr.fr_lock); softi->ipsec_proxy_init = 0; } KFREE(softi); } /* * Setup for a new IPSEC proxy. */ int ipf_p_ipsec_new(void *arg, fr_info_t *fin, ap_session_t *aps, nat_t *nat) { ipf_ipsec_softc_t *softi = arg; ipf_main_softc_t *softc = fin->fin_main_soft; #ifdef USE_MUTEXES ipf_nat_softc_t *softn = softc->ipf_nat_soft; #endif int p, off, dlen, ttl; ipsec_pxy_t *ipsec; ipnat_t *ipn, *np; fr_info_t fi; char *ptr; int size; ip_t *ip; mb_t *m; if (fin->fin_v != 4) return -1; off = fin->fin_plen - fin->fin_dlen + fin->fin_ipoff; bzero(softi->ipsec_buffer, sizeof(softi->ipsec_buffer)); ip = fin->fin_ip; m = fin->fin_m; dlen = M_LEN(m) - off; if (dlen < 16) return -1; COPYDATA(m, off, MIN(sizeof(softi->ipsec_buffer), dlen), softi->ipsec_buffer); if (ipf_nat_outlookup(fin, 0, IPPROTO_ESP, nat->nat_nsrcip, ip->ip_dst) != NULL) return -1; np = nat->nat_ptr; size = np->in_size; KMALLOC(ipsec, ipsec_pxy_t *); if (ipsec == NULL) return -1; KMALLOCS(ipn, ipnat_t *, size); if (ipn == NULL) { KFREE(ipsec); return -1; } aps->aps_data = ipsec; aps->aps_psiz = sizeof(*ipsec); bzero((char *)ipsec, sizeof(*ipsec)); bzero((char *)ipn, size); ipsec->ipsc_rule = ipn; /* * Create NAT rule against which the tunnel/transport mapping is * created. This is required because the current NAT rule does not * describe ESP but UDP instead. */ ipn->in_size = size; ttl = IPF_TTLVAL(softi->ipsec_nat_tqe->ifq_ttl); ipn->in_tqehead[0] = ipf_nat_add_tq(softc, ttl); ipn->in_tqehead[1] = ipf_nat_add_tq(softc, ttl); ipn->in_ifps[0] = fin->fin_ifp; ipn->in_apr = NULL; ipn->in_use = 1; ipn->in_hits = 1; ipn->in_snip = ntohl(nat->nat_nsrcaddr); ipn->in_ippip = 1; ipn->in_osrcip = nat->nat_osrcip; ipn->in_osrcmsk = 0xffffffff; ipn->in_nsrcip = nat->nat_nsrcip; ipn->in_nsrcmsk = 0xffffffff; ipn->in_odstip = nat->nat_odstip; ipn->in_odstmsk = 0xffffffff; ipn->in_ndstip = nat->nat_ndstip; ipn->in_ndstmsk = 0xffffffff; ipn->in_redir = NAT_MAP; ipn->in_pr[0] = IPPROTO_ESP; ipn->in_pr[1] = IPPROTO_ESP; ipn->in_flags = (np->in_flags | IPN_PROXYRULE); MUTEX_INIT(&ipn->in_lock, "IPSec proxy NAT rule"); ipn->in_namelen = np->in_namelen; bcopy(np->in_names, ipn->in_ifnames, ipn->in_namelen); ipn->in_ifnames[0] = np->in_ifnames[0]; ipn->in_ifnames[1] = np->in_ifnames[1]; bcopy((char *)fin, (char *)&fi, sizeof(fi)); fi.fin_fi.fi_p = IPPROTO_ESP; fi.fin_fr = &softi->ipsec_fr; fi.fin_data[0] = 0; fi.fin_data[1] = 0; p = ip->ip_p; ip->ip_p = IPPROTO_ESP; fi.fin_flx &= ~(FI_TCPUDP|FI_STATE|FI_FRAG); fi.fin_flx |= FI_IGNORE; ptr = softi->ipsec_buffer; bcopy(ptr, (char *)ipsec->ipsc_icookie, sizeof(ipsec_cookie_t)); ptr += sizeof(ipsec_cookie_t); bcopy(ptr, (char *)ipsec->ipsc_rcookie, sizeof(ipsec_cookie_t)); /* * The responder cookie should only be non-zero if the initiator * cookie is non-zero. Therefore, it is safe to assume(!) that the * cookies are both set after copying if the responder is non-zero. */ if ((ipsec->ipsc_rcookie[0]|ipsec->ipsc_rcookie[1]) != 0) ipsec->ipsc_rckset = 1; MUTEX_ENTER(&softn->ipf_nat_new); ipsec->ipsc_nat = ipf_nat_add(&fi, ipn, &ipsec->ipsc_nat, NAT_SLAVE|SI_WILDP, NAT_OUTBOUND); MUTEX_EXIT(&softn->ipf_nat_new); if (ipsec->ipsc_nat != NULL) { (void) ipf_nat_proto(&fi, ipsec->ipsc_nat, 0); MUTEX_ENTER(&ipsec->ipsc_nat->nat_lock); ipf_nat_update(&fi, ipsec->ipsc_nat); MUTEX_EXIT(&ipsec->ipsc_nat->nat_lock); fi.fin_data[0] = 0; fi.fin_data[1] = 0; (void) ipf_state_add(softc, &fi, &ipsec->ipsc_state, SI_WILDP); } ip->ip_p = p & 0xff; return 0; } /* * For outgoing IKE packets. refresh timeouts for NAT & state entries, if * we can. If they have disappeared, recreate them. */ int ipf_p_ipsec_inout(void *arg, fr_info_t *fin, ap_session_t *aps, nat_t *nat) { ipf_ipsec_softc_t *softi = arg; ipf_main_softc_t *softc = fin->fin_main_soft; ipsec_pxy_t *ipsec; fr_info_t fi; ip_t *ip; int p; if ((fin->fin_out == 1) && (nat->nat_dir == NAT_INBOUND)) return 0; if ((fin->fin_out == 0) && (nat->nat_dir == NAT_OUTBOUND)) return 0; ipsec = aps->aps_data; if (ipsec != NULL) { ip = fin->fin_ip; p = ip->ip_p; if ((ipsec->ipsc_nat == NULL) || (ipsec->ipsc_state == NULL)) { bcopy((char *)fin, (char *)&fi, sizeof(fi)); fi.fin_fi.fi_p = IPPROTO_ESP; fi.fin_fr = &softi->ipsec_fr; fi.fin_data[0] = 0; fi.fin_data[1] = 0; ip->ip_p = IPPROTO_ESP; fi.fin_flx &= ~(FI_TCPUDP|FI_STATE|FI_FRAG); fi.fin_flx |= FI_IGNORE; } /* * Update NAT timeout/create NAT if missing. */ if (ipsec->ipsc_nat != NULL) ipf_queueback(softc->ipf_ticks, &ipsec->ipsc_nat->nat_tqe); else { #ifdef USE_MUTEXES ipf_nat_softc_t *softn = softc->ipf_nat_soft; #endif MUTEX_ENTER(&softn->ipf_nat_new); ipsec->ipsc_nat = ipf_nat_add(&fi, ipsec->ipsc_rule, &ipsec->ipsc_nat, NAT_SLAVE|SI_WILDP, nat->nat_dir); MUTEX_EXIT(&softn->ipf_nat_new); if (ipsec->ipsc_nat != NULL) { (void) ipf_nat_proto(&fi, ipsec->ipsc_nat, 0); MUTEX_ENTER(&ipsec->ipsc_nat->nat_lock); ipf_nat_update(&fi, ipsec->ipsc_nat); MUTEX_EXIT(&ipsec->ipsc_nat->nat_lock); } } /* * Update state timeout/create state if missing. */ READ_ENTER(&softc->ipf_state); if (ipsec->ipsc_state != NULL) { ipf_queueback(softc->ipf_ticks, &ipsec->ipsc_state->is_sti); ipsec->ipsc_state->is_die = nat->nat_age; RWLOCK_EXIT(&softc->ipf_state); } else { RWLOCK_EXIT(&softc->ipf_state); fi.fin_data[0] = 0; fi.fin_data[1] = 0; (void) ipf_state_add(softc, &fi, &ipsec->ipsc_state, SI_WILDP); } ip->ip_p = p; } return 0; } /* * This extends the NAT matching to be based on the cookies associated with * a session and found at the front of IKE packets. The cookies are always * in the same order (not reversed depending on packet flow direction as with * UDP/TCP port numbers). */ int ipf_p_ipsec_match(fr_info_t *fin, ap_session_t *aps, nat_t *nat) { ipsec_pxy_t *ipsec; u_32_t cookies[4]; mb_t *m; int off; nat = nat; /* LINT */ if ((fin->fin_dlen < sizeof(cookies)) || (fin->fin_flx & FI_FRAG)) return -1; off = fin->fin_plen - fin->fin_dlen + fin->fin_ipoff; ipsec = aps->aps_data; m = fin->fin_m; COPYDATA(m, off, sizeof(cookies), (char *)cookies); if ((cookies[0] != ipsec->ipsc_icookie[0]) || (cookies[1] != ipsec->ipsc_icookie[1])) return -1; if (ipsec->ipsc_rckset == 0) { if ((cookies[2]|cookies[3]) == 0) { return 0; } ipsec->ipsc_rckset = 1; ipsec->ipsc_rcookie[0] = cookies[2]; ipsec->ipsc_rcookie[1] = cookies[3]; return 0; } if ((cookies[2] != ipsec->ipsc_rcookie[0]) || (cookies[3] != ipsec->ipsc_rcookie[1])) return -1; return 0; } /* * clean up after ourselves. */ void ipf_p_ipsec_del(ipf_main_softc_t *softc, ap_session_t *aps) { ipsec_pxy_t *ipsec; ipsec = aps->aps_data; if (ipsec != NULL) { /* * Don't bother changing any of the NAT structure details, * *_del() is on a callback from aps_free(), from nat_delete() */ READ_ENTER(&softc->ipf_state); if (ipsec->ipsc_state != NULL) { ipsec->ipsc_state->is_die = softc->ipf_ticks + 1; ipsec->ipsc_state->is_me = NULL; ipf_queuefront(&ipsec->ipsc_state->is_sti); } RWLOCK_EXIT(&softc->ipf_state); ipsec->ipsc_state = NULL; ipsec->ipsc_nat = NULL; ipsec->ipsc_rule->in_flags |= IPN_DELETE; ipf_nat_rule_deref(softc, &ipsec->ipsc_rule); } }