sys/contrib/ipfilter/netinet/ip_ipsec_pxy.c

   1 /*
   2  * Copyright (C) 2012 by Darren Reed.
   3  *
   4  * See the IPFILTER.LICENCE file for details on licencing.
   5  *
   6  * Simple ISAKMP transparent proxy for in-kernel use.  For use with the NAT
   7  * code.
   8  *
   9  * $Id$
  10  *
  11  */
  12 #define IPF_IPSEC_PROXY
  13
  14
  15 /*
  16  * IPSec proxy
  17  */
  18 typedef struct ipf_ipsec_softc_s {
  19         frentry_t       ipsec_fr;
  20         int             ipsec_proxy_init;
  21         int             ipsec_proxy_ttl;
  22         ipftq_t         *ipsec_nat_tqe;
  23         ipftq_t         *ipsec_state_tqe;
  24         char            ipsec_buffer[1500];
  25 } ipf_ipsec_softc_t;
  26
  27
  28 void *ipf_p_ipsec_soft_create __P((ipf_main_softc_t *));
  29 void ipf_p_ipsec_soft_destroy __P((ipf_main_softc_t *, void *));
  30 int ipf_p_ipsec_soft_init __P((ipf_main_softc_t *, void *));
  31 void ipf_p_ipsec_soft_fini __P((ipf_main_softc_t *, void *));
  32 int ipf_p_ipsec_init __P((void));
  33 void ipf_p_ipsec_fini __P((void));
  34 int ipf_p_ipsec_new __P((void *, fr_info_t *, ap_session_t *, nat_t *));
  35 void ipf_p_ipsec_del __P((ipf_main_softc_t *, ap_session_t *));
  36 int ipf_p_ipsec_inout __P((void *, fr_info_t *, ap_session_t *, nat_t *));
  37 int ipf_p_ipsec_match __P((fr_info_t *, ap_session_t *, nat_t *));
  38
  39
  40 /*
  41  * IPSec application proxy initialization.
  42  */
  43 void *
  44 ipf_p_ipsec_soft_create(softc)
  45         ipf_main_softc_t *softc;
  46 {
  47         ipf_ipsec_softc_t *softi;
  48
  49         KMALLOC(softi, ipf_ipsec_softc_t *);
  50         if (softi == NULL)
  51                 return NULL;
  52
  53         bzero((char *)softi, sizeof(*softi));
  54         softi->ipsec_fr.fr_ref = 1;
  55         softi->ipsec_fr.fr_flags = FR_OUTQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
  56         MUTEX_INIT(&softi->ipsec_fr.fr_lock, "IPsec proxy rule lock");
  57         softi->ipsec_proxy_init = 1;
  58         softi->ipsec_proxy_ttl = 60;
  59
  60         return softi;
  61 }
  62
  63
  64 int
  65 ipf_p_ipsec_soft_init(softc, arg)
  66         ipf_main_softc_t *softc;
  67         void *arg;
  68 {
  69         ipf_ipsec_softc_t *softi = arg;
  70
  71         softi->ipsec_nat_tqe = ipf_state_add_tq(softc, softi->ipsec_proxy_ttl);
  72         if (softi->ipsec_nat_tqe == NULL)
  73                 return -1;
  74         softi->ipsec_state_tqe = ipf_nat_add_tq(softc, softi->ipsec_proxy_ttl);
  75         if (softi->ipsec_state_tqe == NULL) {
  76                 if (ipf_deletetimeoutqueue(softi->ipsec_nat_tqe) == 0)
  77                         ipf_freetimeoutqueue(softc, softi->ipsec_nat_tqe);
  78                 softi->ipsec_nat_tqe = NULL;
  79                 return -1;
  80         }
  81
  82         softi->ipsec_nat_tqe->ifq_flags |= IFQF_PROXY;
  83         softi->ipsec_state_tqe->ifq_flags |= IFQF_PROXY;
  84         softi->ipsec_fr.fr_age[0] = softi->ipsec_proxy_ttl;
  85         softi->ipsec_fr.fr_age[1] = softi->ipsec_proxy_ttl;
  86         return 0;
  87 }
  88
  89
  90 void
  91 ipf_p_ipsec_soft_fini(softc, arg)
  92         ipf_main_softc_t *softc;
  93         void *arg;
  94 {
  95         ipf_ipsec_softc_t *softi = arg;
  96
  97         if (arg == NULL)
  98                 return;
  99
 100         if (softi->ipsec_nat_tqe != NULL) {
 101                 if (ipf_deletetimeoutqueue(softi->ipsec_nat_tqe) == 0)
 102                         ipf_freetimeoutqueue(softc, softi->ipsec_nat_tqe);
 103         }
 104         softi->ipsec_nat_tqe = NULL;
 105         if (softi->ipsec_state_tqe != NULL) {
 106                 if (ipf_deletetimeoutqueue(softi->ipsec_state_tqe) == 0)
 107                         ipf_freetimeoutqueue(softc, softi->ipsec_state_tqe);
 108         }
 109         softi->ipsec_state_tqe = NULL;
 110 }
 111
 112
 113 void
 114 ipf_p_ipsec_soft_destroy(softc, arg)
 115         ipf_main_softc_t *softc;
 116         void *arg;
 117 {
 118         ipf_ipsec_softc_t *softi = arg;
 119
 120         if (softi->ipsec_proxy_init == 1) {
 121                 MUTEX_DESTROY(&softi->ipsec_fr.fr_lock);
 122                 softi->ipsec_proxy_init = 0;
 123         }
 124
 125         KFREE(softi);
 126 }
 127
 128
 129 /*
 130  * Setup for a new IPSEC proxy.
 131  */
 132 int
 133 ipf_p_ipsec_new(arg, fin, aps, nat)
 134         void *arg;
 135         fr_info_t *fin;
 136         ap_session_t *aps;
 137         nat_t *nat;
 138 {
 139         ipf_ipsec_softc_t *softi = arg;
 140         ipf_main_softc_t *softc = fin->fin_main_soft;
 141 #ifdef USE_MUTEXES
 142         ipf_nat_softc_t *softn = softc->ipf_nat_soft;
 143 #endif
 144         int p, off, dlen, ttl;
 145         ipsec_pxy_t *ipsec;
 146         ipnat_t *ipn, *np;
 147         fr_info_t fi;
 148         char *ptr;
 149         int size;
 150         ip_t *ip;
 151         mb_t *m;
 152
 153         if (fin->fin_v != 4)
 154                 return -1;
 155
 156         off = fin->fin_plen - fin->fin_dlen + fin->fin_ipoff;
 157         bzero(softi->ipsec_buffer, sizeof(softi->ipsec_buffer));
 158         ip = fin->fin_ip;
 159         m = fin->fin_m;
 160
 161         dlen = M_LEN(m) - off;
 162         if (dlen < 16)
 163                 return -1;
 164         COPYDATA(m, off, MIN(sizeof(softi->ipsec_buffer), dlen),
 165                  softi->ipsec_buffer);
 166
 167         if (ipf_nat_outlookup(fin, 0, IPPROTO_ESP, nat->nat_nsrcip,
 168                           ip->ip_dst) != NULL)
 169                 return -1;
 170
 171         np = nat->nat_ptr;
 172         size = np->in_size;
 173         KMALLOC(ipsec, ipsec_pxy_t *);
 174         if (ipsec == NULL)
 175                 return -1;
 176
 177         KMALLOCS(ipn, ipnat_t *, size);
 178         if (ipn == NULL) {
 179                 KFREE(ipsec);
 180                 return -1;
 181         }
 182
 183         aps->aps_data = ipsec;
 184         aps->aps_psiz = sizeof(*ipsec);
 185         bzero((char *)ipsec, sizeof(*ipsec));
 186         bzero((char *)ipn, size);
 187         ipsec->ipsc_rule = ipn;
 188
 189         /*
 190          * Create NAT rule against which the tunnel/transport mapping is
 191          * created.  This is required because the current NAT rule does not
 192          * describe ESP but UDP instead.
 193          */
 194         ipn->in_size = size;
 195         ttl = IPF_TTLVAL(softi->ipsec_nat_tqe->ifq_ttl);
 196         ipn->in_tqehead[0] = ipf_nat_add_tq(softc, ttl);
 197         ipn->in_tqehead[1] = ipf_nat_add_tq(softc, ttl);
 198         ipn->in_ifps[0] = fin->fin_ifp;
 199         ipn->in_apr = NULL;
 200         ipn->in_use = 1;
 201         ipn->in_hits = 1;
 202         ipn->in_snip = ntohl(nat->nat_nsrcaddr);
 203         ipn->in_ippip = 1;
 204         ipn->in_osrcip = nat->nat_osrcip;
 205         ipn->in_osrcmsk = 0xffffffff;
 206         ipn->in_nsrcip = nat->nat_nsrcip;
 207         ipn->in_nsrcmsk = 0xffffffff;
 208         ipn->in_odstip = nat->nat_odstip;
 209         ipn->in_odstmsk = 0xffffffff;
 210         ipn->in_ndstip = nat->nat_ndstip;
 211         ipn->in_ndstmsk = 0xffffffff;
 212         ipn->in_redir = NAT_MAP;
 213         ipn->in_pr[0] = IPPROTO_ESP;
 214         ipn->in_pr[1] = IPPROTO_ESP;
 215         ipn->in_flags = (np->in_flags | IPN_PROXYRULE);
 216         MUTEX_INIT(&ipn->in_lock, "IPSec proxy NAT rule");
 217
 218         ipn->in_namelen = np->in_namelen;
 219         bcopy(np->in_names, ipn->in_ifnames, ipn->in_namelen);
 220         ipn->in_ifnames[0] = np->in_ifnames[0];
 221         ipn->in_ifnames[1] = np->in_ifnames[1];
 222
 223         bcopy((char *)fin, (char *)&fi, sizeof(fi));
 224         fi.fin_fi.fi_p = IPPROTO_ESP;
 225         fi.fin_fr = &softi->ipsec_fr;
 226         fi.fin_data[0] = 0;
 227         fi.fin_data[1] = 0;
 228         p = ip->ip_p;
 229         ip->ip_p = IPPROTO_ESP;
 230         fi.fin_flx &= ~(FI_TCPUDP|FI_STATE|FI_FRAG);
 231         fi.fin_flx |= FI_IGNORE;
 232
 233         ptr = softi->ipsec_buffer;
 234         bcopy(ptr, (char *)ipsec->ipsc_icookie, sizeof(ipsec_cookie_t));
 235         ptr += sizeof(ipsec_cookie_t);
 236         bcopy(ptr, (char *)ipsec->ipsc_rcookie, sizeof(ipsec_cookie_t));
 237         /*
 238          * The responder cookie should only be non-zero if the initiator
 239          * cookie is non-zero.  Therefore, it is safe to assume(!) that the
 240          * cookies are both set after copying if the responder is non-zero.
 241          */
 242         if ((ipsec->ipsc_rcookie[0]|ipsec->ipsc_rcookie[1]) != 0)
 243                 ipsec->ipsc_rckset = 1;
 244
 245         MUTEX_ENTER(&softn->ipf_nat_new);
 246         ipsec->ipsc_nat = ipf_nat_add(&fi, ipn, &ipsec->ipsc_nat,
 247                                       NAT_SLAVE|SI_WILDP, NAT_OUTBOUND);
 248         MUTEX_EXIT(&softn->ipf_nat_new);
 249         if (ipsec->ipsc_nat != NULL) {
 250                 (void) ipf_nat_proto(&fi, ipsec->ipsc_nat, 0);
 251                 MUTEX_ENTER(&ipsec->ipsc_nat->nat_lock);
 252                 ipf_nat_update(&fi, ipsec->ipsc_nat);
 253                 MUTEX_EXIT(&ipsec->ipsc_nat->nat_lock);
 254
 255                 fi.fin_data[0] = 0;
 256                 fi.fin_data[1] = 0;
 257                 (void) ipf_state_add(softc, &fi, &ipsec->ipsc_state, SI_WILDP);
 258         }
 259         ip->ip_p = p & 0xff;
 260         return 0;
 261 }
 262
 263
 264 /*
 265  * For outgoing IKE packets.  refresh timeouts for NAT & state entries, if
 266  * we can.  If they have disappeared, recreate them.
 267  */
 268 int
 269 ipf_p_ipsec_inout(arg, fin, aps, nat)
 270         void *arg;
 271         fr_info_t *fin;
 272         ap_session_t *aps;
 273         nat_t *nat;
 274 {
 275         ipf_ipsec_softc_t *softi = arg;
 276         ipf_main_softc_t *softc = fin->fin_main_soft;
 277         ipsec_pxy_t *ipsec;
 278         fr_info_t fi;
 279         ip_t *ip;
 280         int p;
 281
 282         if ((fin->fin_out == 1) && (nat->nat_dir == NAT_INBOUND))
 283                 return 0;
 284
 285         if ((fin->fin_out == 0) && (nat->nat_dir == NAT_OUTBOUND))
 286                 return 0;
 287
 288         ipsec = aps->aps_data;
 289
 290         if (ipsec != NULL) {
 291                 ip = fin->fin_ip;
 292                 p = ip->ip_p;
 293
 294                 if ((ipsec->ipsc_nat == NULL) || (ipsec->ipsc_state == NULL)) {
 295                         bcopy((char *)fin, (char *)&fi, sizeof(fi));
 296                         fi.fin_fi.fi_p = IPPROTO_ESP;
 297                         fi.fin_fr = &softi->ipsec_fr;
 298                         fi.fin_data[0] = 0;
 299                         fi.fin_data[1] = 0;
 300                         ip->ip_p = IPPROTO_ESP;
 301                         fi.fin_flx &= ~(FI_TCPUDP|FI_STATE|FI_FRAG);
 302                         fi.fin_flx |= FI_IGNORE;
 303                 }
 304
 305                 /*
 306                  * Update NAT timeout/create NAT if missing.
 307                  */
 308                 if (ipsec->ipsc_nat != NULL)
 309                         ipf_queueback(softc->ipf_ticks,
 310                                       &ipsec->ipsc_nat->nat_tqe);
 311                 else {
 312 #ifdef USE_MUTEXES
 313                         ipf_nat_softc_t *softn = softc->ipf_nat_soft;
 314 #endif
 315
 316                         MUTEX_ENTER(&softn->ipf_nat_new);
 317                         ipsec->ipsc_nat = ipf_nat_add(&fi, ipsec->ipsc_rule,
 318                                                       &ipsec->ipsc_nat,
 319                                                       NAT_SLAVE|SI_WILDP,
 320                                                       nat->nat_dir);
 321                         MUTEX_EXIT(&softn->ipf_nat_new);
 322                         if (ipsec->ipsc_nat != NULL) {
 323                                 (void) ipf_nat_proto(&fi, ipsec->ipsc_nat, 0);
 324                                 MUTEX_ENTER(&ipsec->ipsc_nat->nat_lock);
 325                                 ipf_nat_update(&fi, ipsec->ipsc_nat);
 326                                 MUTEX_EXIT(&ipsec->ipsc_nat->nat_lock);
 327                         }
 328                 }
 329
 330                 /*
 331                  * Update state timeout/create state if missing.
 332                  */
 333                 READ_ENTER(&softc->ipf_state);
 334                 if (ipsec->ipsc_state != NULL) {
 335                         ipf_queueback(softc->ipf_ticks,
 336                                       &ipsec->ipsc_state->is_sti);
 337                         ipsec->ipsc_state->is_die = nat->nat_age;
 338                         RWLOCK_EXIT(&softc->ipf_state);
 339                 } else {
 340                         RWLOCK_EXIT(&softc->ipf_state);
 341                         fi.fin_data[0] = 0;
 342                         fi.fin_data[1] = 0;
 343                         (void) ipf_state_add(softc, &fi, &ipsec->ipsc_state,
 344                                              SI_WILDP);
 345                 }
 346                 ip->ip_p = p;
 347         }
 348         return 0;
 349 }
 350
 351
 352 /*
 353  * This extends the NAT matching to be based on the cookies associated with
 354  * a session and found at the front of IKE packets.  The cookies are always
 355  * in the same order (not reversed depending on packet flow direction as with
 356  * UDP/TCP port numbers).
 357  */
 358 int
 359 ipf_p_ipsec_match(fin, aps, nat)
 360         fr_info_t *fin;
 361         ap_session_t *aps;
 362         nat_t *nat;
 363 {
 364         ipsec_pxy_t *ipsec;
 365         u_32_t cookies[4];
 366         mb_t *m;
 367         int off;
 368
 369         nat = nat;      /* LINT */
 370
 371         if ((fin->fin_dlen < sizeof(cookies)) || (fin->fin_flx & FI_FRAG))
 372                 return -1;
 373
 374         off = fin->fin_plen - fin->fin_dlen + fin->fin_ipoff;
 375         ipsec = aps->aps_data;
 376         m = fin->fin_m;
 377         COPYDATA(m, off, sizeof(cookies), (char *)cookies);
 378
 379         if ((cookies[0] != ipsec->ipsc_icookie[0]) ||
 380             (cookies[1] != ipsec->ipsc_icookie[1]))
 381                 return -1;
 382
 383         if (ipsec->ipsc_rckset == 0) {
 384                 if ((cookies[2]|cookies[3]) == 0) {
 385                         return 0;
 386                 }
 387                 ipsec->ipsc_rckset = 1;
 388                 ipsec->ipsc_rcookie[0] = cookies[2];
 389                 ipsec->ipsc_rcookie[1] = cookies[3];
 390                 return 0;
 391         }
 392
 393         if ((cookies[2] != ipsec->ipsc_rcookie[0]) ||
 394             (cookies[3] != ipsec->ipsc_rcookie[1]))
 395                 return -1;
 396         return 0;
 397 }
 398
 399
 400 /*
 401  * clean up after ourselves.
 402  */
 403 void
 404 ipf_p_ipsec_del(softc, aps)
 405         ipf_main_softc_t *softc;
 406         ap_session_t *aps;
 407 {
 408         ipsec_pxy_t *ipsec;
 409
 410         ipsec = aps->aps_data;
 411
 412         if (ipsec != NULL) {
 413                 /*
 414                  * Don't bother changing any of the NAT structure details,
 415                  * *_del() is on a callback from aps_free(), from nat_delete()
 416                  */
 417
 418                 READ_ENTER(&softc->ipf_state);
 419                 if (ipsec->ipsc_state != NULL) {
 420                         ipsec->ipsc_state->is_die = softc->ipf_ticks + 1;
 421                         ipsec->ipsc_state->is_me = NULL;
 422                         ipf_queuefront(&ipsec->ipsc_state->is_sti);
 423                 }
 424                 RWLOCK_EXIT(&softc->ipf_state);
 425
 426                 ipsec->ipsc_state = NULL;
 427                 ipsec->ipsc_nat = NULL;
 428                 ipsec->ipsc_rule->in_flags |= IPN_DELETE;
 429                 ipf_nat_rule_deref(softc, &ipsec->ipsc_rule);
 430         }
 431 }