sys/dist/ipf/netinet/ip_ipsec_pxy.c

   1 /*      $NetBSD$        */
   2
   3 /*
   4  * Copyright (C) 2001-2003 by Darren Reed
   5  *
   6  * See the IPFILTER.LICENCE file for details on licencing.
   7  *
   8  * Simple ISAKMP transparent proxy for in-kernel use.  For use with the NAT
   9  * code.
  10  *
  11  * Id: ip_ipsec_pxy.c,v 2.20.2.11 2008/11/06 21:18:34 darrenr Exp
  12  *
  13  */
  14
  15 #include <sys/cdefs.h>
  16 __KERNEL_RCSID(1, "$NetBSD$");
  17
  18 #define IPF_IPSEC_PROXY
  19
  20
  21 int ippr_ipsec_init __P((void));
  22 void ippr_ipsec_fini __P((void));
  23 int ippr_ipsec_new __P((fr_info_t *, ap_session_t *, nat_t *));
  24 void ippr_ipsec_del __P((ap_session_t *));
  25 int ippr_ipsec_inout __P((fr_info_t *, ap_session_t *, nat_t *));
  26 int ippr_ipsec_match __P((fr_info_t *, ap_session_t *, nat_t *));
  27
  28 static  frentry_t       ipsecfr;
  29 static  ipftq_t         *ipsecnattqe;
  30 static  ipftq_t         *ipsecstatetqe;
  31 static  char    ipsec_buffer[1500];
  32
  33 int     ipsec_proxy_init = 0;
  34 int     ipsec_proxy_ttl = 60;
  35
  36 /*
  37  * IPSec application proxy initialization.
  38  */
  39 int ippr_ipsec_init()
  40 {
  41         bzero((char *)&ipsecfr, sizeof(ipsecfr));
  42         ipsecfr.fr_ref = 1;
  43         ipsecfr.fr_flags = FR_OUTQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
  44         MUTEX_INIT(&ipsecfr.fr_lock, "IPsec proxy rule lock");
  45         ipsec_proxy_init = 1;
  46
  47         ipsecnattqe = fr_addtimeoutqueue(&nat_utqe, ipsec_proxy_ttl);
  48         if (ipsecnattqe == NULL)
  49                 return -1;
  50         ipsecstatetqe = fr_addtimeoutqueue(&ips_utqe, ipsec_proxy_ttl);
  51         if (ipsecstatetqe == NULL) {
  52                 if (fr_deletetimeoutqueue(ipsecnattqe) == 0)
  53                         fr_freetimeoutqueue(ipsecnattqe);
  54                 ipsecnattqe = NULL;
  55                 return -1;
  56         }
  57
  58         ipsecnattqe->ifq_flags |= IFQF_PROXY;
  59         ipsecstatetqe->ifq_flags |= IFQF_PROXY;
  60
  61         ipsecfr.fr_age[0] = ipsec_proxy_ttl;
  62         ipsecfr.fr_age[1] = ipsec_proxy_ttl;
  63         return 0;
  64 }
  65
  66
  67 void ippr_ipsec_fini()
  68 {
  69         if (ipsecnattqe != NULL) {
  70                 if (fr_deletetimeoutqueue(ipsecnattqe) == 0)
  71                         fr_freetimeoutqueue(ipsecnattqe);
  72         }
  73         ipsecnattqe = NULL;
  74         if (ipsecstatetqe != NULL) {
  75                 if (fr_deletetimeoutqueue(ipsecstatetqe) == 0)
  76                         fr_freetimeoutqueue(ipsecstatetqe);
  77         }
  78         ipsecstatetqe = NULL;
  79
  80         if (ipsec_proxy_init == 1) {
  81                 MUTEX_DESTROY(&ipsecfr.fr_lock);
  82                 ipsec_proxy_init = 0;
  83         }
  84 }
  85
  86
  87 /*
  88  * Setup for a new IPSEC proxy.
  89  */
  90 int ippr_ipsec_new(fin, aps, nat)
  91 fr_info_t *fin;
  92 ap_session_t *aps;
  93 nat_t *nat;
  94 {
  95         ipsec_pxy_t *ipsec;
  96         fr_info_t fi;
  97         ipnat_t *ipn;
  98         char *ptr;
  99         int p, off, dlen, ttl;
 100         mb_t *m;
 101         ip_t *ip;
 102
 103         off = fin->fin_plen - fin->fin_dlen + fin->fin_ipoff;
 104         bzero(ipsec_buffer, sizeof(ipsec_buffer));
 105         ip = fin->fin_ip;
 106         m = fin->fin_m;
 107
 108         dlen = M_LEN(m) - off;
 109         if (dlen < 16)
 110                 return -1;
 111         COPYDATA(m, off, MIN(sizeof(ipsec_buffer), dlen), ipsec_buffer);
 112
 113         if (nat_outlookup(fin, 0, IPPROTO_ESP, nat->nat_inip,
 114                           ip->ip_dst) != NULL)
 115                 return -1;
 116
 117         aps->aps_psiz = sizeof(*ipsec);
 118         KMALLOCS(aps->aps_data, ipsec_pxy_t *, sizeof(*ipsec));
 119         if (aps->aps_data == NULL)
 120                 return -1;
 121
 122         ipsec = aps->aps_data;
 123         bzero((char *)ipsec, sizeof(*ipsec));
 124
 125         /*
 126          * Create NAT rule against which the tunnel/transport mapping is
 127          * created.  This is required because the current NAT rule does not
 128          * describe ESP but UDP instead.
 129          */
 130         ipn = &ipsec->ipsc_rule;
 131         ttl = IPF_TTLVAL(ipsecnattqe->ifq_ttl);
 132         ipn->in_tqehead[0] = fr_addtimeoutqueue(&nat_utqe, ttl);
 133         ipn->in_tqehead[1] = fr_addtimeoutqueue(&nat_utqe, ttl);
 134         ipn->in_ifps[0] = fin->fin_ifp;
 135         ipn->in_apr = NULL;
 136         ipn->in_use = 1;
 137         ipn->in_hits = 1;
 138         ipn->in_nip = ntohl(nat->nat_outip.s_addr);
 139         ipn->in_ippip = 1;
 140         ipn->in_inip = nat->nat_inip.s_addr;
 141         ipn->in_inmsk = 0xffffffff;
 142         ipn->in_outip = fin->fin_saddr;
 143         ipn->in_outmsk = nat->nat_outip.s_addr;
 144         ipn->in_srcip = fin->fin_saddr;
 145         ipn->in_srcmsk = 0xffffffff;
 146         ipn->in_redir = NAT_MAP;
 147         bcopy(nat->nat_ptr->in_ifnames[0], ipn->in_ifnames[0],
 148               sizeof(ipn->in_ifnames[0]));
 149         ipn->in_p = IPPROTO_ESP;
 150
 151         bcopy((char *)fin, (char *)&fi, sizeof(fi));
 152         fi.fin_fi.fi_p = IPPROTO_ESP;
 153         fi.fin_fr = &ipsecfr;
 154         fi.fin_data[0] = 0;
 155         fi.fin_data[1] = 0;
 156         p = ip->ip_p;
 157         ip->ip_p = IPPROTO_ESP;
 158         fi.fin_flx &= ~(FI_TCPUDP|FI_STATE|FI_FRAG);
 159         fi.fin_flx |= FI_IGNORE;
 160
 161         ptr = ipsec_buffer;
 162         bcopy(ptr, (char *)ipsec->ipsc_icookie, sizeof(ipsec_cookie_t));
 163         ptr += sizeof(ipsec_cookie_t);
 164         bcopy(ptr, (char *)ipsec->ipsc_rcookie, sizeof(ipsec_cookie_t));
 165         /*
 166          * The responder cookie should only be non-zero if the initiator
 167          * cookie is non-zero.  Therefore, it is safe to assume(!) that the
 168          * cookies are both set after copying if the responder is non-zero.
 169          */
 170         if ((ipsec->ipsc_rcookie[0]|ipsec->ipsc_rcookie[1]) != 0)
 171                 ipsec->ipsc_rckset = 1;
 172
 173         MUTEX_ENTER(&ipf_nat_new);
 174         ipsec->ipsc_nat = nat_new(&fi, ipn, &ipsec->ipsc_nat,
 175                                   NAT_SLAVE|SI_WILDP, NAT_OUTBOUND);
 176         MUTEX_EXIT(&ipf_nat_new);
 177         if (ipsec->ipsc_nat != NULL) {
 178                 (void) nat_proto(&fi, ipsec->ipsc_nat, 0);
 179                 MUTEX_ENTER(&ipsec->ipsc_nat->nat_lock);
 180                 nat_update(&fi, ipsec->ipsc_nat);
 181                 MUTEX_EXIT(&ipsec->ipsc_nat->nat_lock);
 182
 183                 fi.fin_data[0] = 0;
 184                 fi.fin_data[1] = 0;
 185                 ipsec->ipsc_state = fr_addstate(&fi, &ipsec->ipsc_state,
 186                                                 SI_WILDP);
 187         }
 188         ip->ip_p = p & 0xff;
 189         return 0;
 190 }
 191
 192
 193 /*
 194  * For outgoing IKE packets.  refresh timeouts for NAT & state entries, if
 195  * we can.  If they have disappeared, recreate them.
 196  */
 197 int ippr_ipsec_inout(fin, aps, nat)
 198 fr_info_t *fin;
 199 ap_session_t *aps;
 200 nat_t *nat;
 201 {
 202         ipsec_pxy_t *ipsec;
 203         fr_info_t fi;
 204         ip_t *ip;
 205         int p;
 206
 207         if ((fin->fin_out == 1) && (nat->nat_dir == NAT_INBOUND))
 208                 return 0;
 209
 210         if ((fin->fin_out == 0) && (nat->nat_dir == NAT_OUTBOUND))
 211                 return 0;
 212
 213         ipsec = aps->aps_data;
 214
 215         if (ipsec != NULL) {
 216                 ip = fin->fin_ip;
 217                 p = ip->ip_p;
 218
 219                 if ((ipsec->ipsc_nat == NULL) || (ipsec->ipsc_state == NULL)) {
 220                         bcopy((char *)fin, (char *)&fi, sizeof(fi));
 221                         fi.fin_fi.fi_p = IPPROTO_ESP;
 222                         fi.fin_fr = &ipsecfr;
 223                         fi.fin_data[0] = 0;
 224                         fi.fin_data[1] = 0;
 225                         ip->ip_p = IPPROTO_ESP;
 226                         fi.fin_flx &= ~(FI_TCPUDP|FI_STATE|FI_FRAG);
 227                         fi.fin_flx |= FI_IGNORE;
 228                 }
 229
 230                 /*
 231                  * Update NAT timeout/create NAT if missing.
 232                  */
 233                 if (ipsec->ipsc_nat != NULL)
 234                         fr_queueback(&ipsec->ipsc_nat->nat_tqe);
 235                 else {
 236                         MUTEX_ENTER(&ipf_nat_new);
 237                         ipsec->ipsc_nat = nat_new(&fi, &ipsec->ipsc_rule,
 238                                                   &ipsec->ipsc_nat,
 239                                                   NAT_SLAVE|SI_WILDP,
 240                                                   nat->nat_dir);
 241                         MUTEX_EXIT(&ipf_nat_new);
 242                         if (ipsec->ipsc_nat != NULL) {
 243                                 (void) nat_proto(&fi, ipsec->ipsc_nat, 0);
 244                                 MUTEX_ENTER(&ipsec->ipsc_nat->nat_lock);
 245                                 nat_update(&fi, ipsec->ipsc_nat);
 246                                 MUTEX_EXIT(&ipsec->ipsc_nat->nat_lock);
 247                         }
 248                 }
 249
 250                 /*
 251                  * Update state timeout/create state if missing.
 252                  */
 253                 READ_ENTER(&ipf_state);
 254                 if (ipsec->ipsc_state != NULL) {
 255                         fr_queueback(&ipsec->ipsc_state->is_sti);
 256                         ipsec->ipsc_state->is_die = nat->nat_age;
 257                         RWLOCK_EXIT(&ipf_state);
 258                 } else {
 259                         RWLOCK_EXIT(&ipf_state);
 260                         fi.fin_data[0] = 0;
 261                         fi.fin_data[1] = 0;
 262                         ipsec->ipsc_state = fr_addstate(&fi,
 263                                                         &ipsec->ipsc_state,
 264                                                         SI_WILDP);
 265                 }
 266                 ip->ip_p = p;
 267         }
 268         return 0;
 269 }
 270
 271
 272 /*
 273  * This extends the NAT matching to be based on the cookies associated with
 274  * a session and found at the front of IKE packets.  The cookies are always
 275  * in the same order (not reversed depending on packet flow direction as with
 276  * UDP/TCP port numbers).
 277  */
 278 int ippr_ipsec_match(fin, aps, nat)
 279 fr_info_t *fin;
 280 ap_session_t *aps;
 281 nat_t *nat;
 282 {
 283         ipsec_pxy_t *ipsec;
 284         u_32_t cookies[4];
 285         mb_t *m;
 286         int off;
 287
 288         nat = nat;      /* LINT */
 289
 290         if ((fin->fin_dlen < sizeof(cookies)) || (fin->fin_flx & FI_FRAG))
 291                 return -1;
 292
 293         off = fin->fin_plen - fin->fin_dlen + fin->fin_ipoff;
 294         ipsec = aps->aps_data;
 295         m = fin->fin_m;
 296         COPYDATA(m, off, sizeof(cookies), (char *)cookies);
 297
 298         if ((cookies[0] != ipsec->ipsc_icookie[0]) ||
 299             (cookies[1] != ipsec->ipsc_icookie[1]))
 300                 return -1;
 301
 302         if (ipsec->ipsc_rckset == 0) {
 303                 if ((cookies[2]|cookies[3]) == 0) {
 304                         return 0;
 305                 }
 306                 ipsec->ipsc_rckset = 1;
 307                 ipsec->ipsc_rcookie[0] = cookies[2];
 308                 ipsec->ipsc_rcookie[1] = cookies[3];
 309                 return 0;
 310         }
 311
 312         if ((cookies[2] != ipsec->ipsc_rcookie[0]) ||
 313             (cookies[3] != ipsec->ipsc_rcookie[1]))
 314                 return -1;
 315         return 0;
 316 }
 317
 318
 319 /*
 320  * clean up after ourselves.
 321  */
 322 void ippr_ipsec_del(aps)
 323 ap_session_t *aps;
 324 {
 325         ipsec_pxy_t *ipsec;
 326
 327         ipsec = aps->aps_data;
 328
 329         if (ipsec != NULL) {
 330                 /*
 331                  * Don't bother changing any of the NAT structure details,
 332                  * *_del() is on a callback from aps_free(), from nat_delete()
 333                  */
 334
 335                 READ_ENTER(&ipf_state);
 336                 if (ipsec->ipsc_state != NULL) {
 337                         ipsec->ipsc_state->is_die = fr_ticks + 1;
 338                         ipsec->ipsc_state->is_me = NULL;
 339                         fr_queuefront(&ipsec->ipsc_state->is_sti);
 340                 }
 341                 RWLOCK_EXIT(&ipf_state);
 342
 343                 ipsec->ipsc_state = NULL;
 344                 ipsec->ipsc_nat = NULL;
 345         }
 346 }