| 1 | /* $NetBSD: portalgo.c,v 1.10 2016/04/26 08:44:44 ozaki-r Exp $ */ |
| 2 | |
| 3 | /* |
| 4 | * Copyright 2011 Vlad Balan |
| 5 | * |
| 6 | * Written by Vlad Balan for the NetBSD Foundation. |
| 7 | * |
| 8 | * Redistribution and use in source and binary forms, with or without |
| 9 | * modification, are permitted provided that the following conditions |
| 10 | * are met: |
| 11 | * 1. Redistributions of source code must retain the above copyright |
| 12 | * notice, this list of conditions and the following disclaimer. |
| 13 | * 2. Redistributions in binary form must reproduce the above copyright |
| 14 | * notice, this list of conditions and the following disclaimer in the |
| 15 | * documentation and/or other materials provided with the distribution. |
| 16 | * |
| 17 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 18 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 19 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 20 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 21 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 22 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 23 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 24 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 25 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 26 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 27 | * SUCH DAMAGE. |
| 28 | * |
| 29 | */ |
| 30 | |
| 31 | /* |
| 32 | * see: |
| 33 | * RFC 6056 Recommendations for Transport-Protocol Port Randomization |
| 34 | */ |
| 35 | |
| 36 | #include <sys/cdefs.h> |
| 37 | __KERNEL_RCSID(0, "$NetBSD: portalgo.c,v 1.10 2016/04/26 08:44:44 ozaki-r Exp $" ); |
| 38 | |
| 39 | #ifdef _KERNEL_OPT |
| 40 | #include "opt_inet.h" |
| 41 | #endif |
| 42 | |
| 43 | #include <sys/param.h> |
| 44 | #include <sys/errno.h> |
| 45 | #include <sys/kauth.h> |
| 46 | #include <sys/uidinfo.h> |
| 47 | #include <sys/domain.h> |
| 48 | #include <sys/md5.h> |
| 49 | #include <sys/cprng.h> |
| 50 | #include <sys/bitops.h> |
| 51 | |
| 52 | #include <net/if.h> |
| 53 | |
| 54 | #include <netinet/in.h> |
| 55 | #include <netinet/in_systm.h> |
| 56 | #include <netinet/ip.h> |
| 57 | #include <netinet/in_pcb.h> |
| 58 | #include <netinet/in_var.h> |
| 59 | #include <netinet/ip_var.h> |
| 60 | |
| 61 | #ifdef INET6 |
| 62 | #include <netinet/ip6.h> |
| 63 | #include <netinet6/ip6_var.h> |
| 64 | #include <netinet6/in6_pcb.h> |
| 65 | #endif |
| 66 | |
| 67 | #include <netinet/tcp_vtw.h> |
| 68 | |
| 69 | #include "portalgo.h" |
| 70 | |
| 71 | #define NPROTO 2 |
| 72 | #define PORTALGO_TCP 0 |
| 73 | #define PORTALGO_UDP 1 |
| 74 | |
| 75 | #define NAF 2 |
| 76 | #define PORTALGO_IPV4 0 |
| 77 | #define PORTALGO_IPV6 1 |
| 78 | |
| 79 | #define NRANGES 2 |
| 80 | #define PORTALGO_LOWPORT 0 |
| 81 | #define PORTALGO_HIGHPORT 1 |
| 82 | |
| 83 | #if PORTALGO_DEBUG |
| 84 | static bool portalgo_debug = true; |
| 85 | #define DPRINTF if (portalgo_debug) printf |
| 86 | #else |
| 87 | #define DPRINTF while (/*CONSTCOND*/0) printf |
| 88 | #endif |
| 89 | |
| 90 | #ifndef PORTALGO_INET4_DEFAULT |
| 91 | #define PORTALGO_INET4_DEFAULT PORTALGO_BSD |
| 92 | #endif |
| 93 | #ifndef PORTALGO_INET6_DEFAULT |
| 94 | #define PORTALGO_INET6_DEFAULT PORTALGO_BSD |
| 95 | #endif |
| 96 | |
| 97 | typedef __BITMAP_TYPE(, uint32_t, 0x10000) bitmap; |
| 98 | #ifdef INET |
| 99 | static int inet4_portalgo = PORTALGO_INET4_DEFAULT; |
| 100 | static bitmap inet4_reserve; |
| 101 | #endif |
| 102 | #ifdef INET6 |
| 103 | static int inet6_portalgo = PORTALGO_INET6_DEFAULT; |
| 104 | static bitmap inet6_reserve; |
| 105 | #endif |
| 106 | |
| 107 | typedef struct { |
| 108 | const char *name; |
| 109 | int (*func)(int, uint16_t *, struct inpcb_hdr *, kauth_cred_t); |
| 110 | } portalgo_algorithm_t; |
| 111 | |
| 112 | static int algo_bsd(int, uint16_t *, struct inpcb_hdr *, kauth_cred_t); |
| 113 | static int algo_random_start(int, uint16_t *, struct inpcb_hdr *, kauth_cred_t); |
| 114 | static int algo_random_pick(int, uint16_t *, struct inpcb_hdr *, kauth_cred_t); |
| 115 | static int algo_hash(int, uint16_t *, struct inpcb_hdr *, kauth_cred_t); |
| 116 | static int algo_doublehash(int, uint16_t *, struct inpcb_hdr *, kauth_cred_t); |
| 117 | static int algo_randinc(int, uint16_t *, struct inpcb_hdr *, kauth_cred_t); |
| 118 | |
| 119 | static const portalgo_algorithm_t algos[] = { |
| 120 | { |
| 121 | .name = "bsd" , |
| 122 | .func = algo_bsd |
| 123 | }, |
| 124 | { |
| 125 | .name = "random_start" , |
| 126 | .func = algo_random_start |
| 127 | }, |
| 128 | { |
| 129 | .name = "random_pick" , |
| 130 | .func = algo_random_pick |
| 131 | }, |
| 132 | { |
| 133 | .name = "hash" , |
| 134 | .func = algo_hash |
| 135 | }, |
| 136 | { |
| 137 | .name = "doublehash" , |
| 138 | .func = algo_doublehash |
| 139 | }, |
| 140 | { |
| 141 | .name = "randinc" , |
| 142 | .func = algo_randinc |
| 143 | } |
| 144 | }; |
| 145 | |
| 146 | #define NALGOS __arraycount(algos) |
| 147 | |
| 148 | static uint16_t portalgo_next_ephemeral[NPROTO][NAF][NRANGES][NALGOS]; |
| 149 | |
| 150 | /* |
| 151 | * Access the pcb and copy the values of the last port and the ends of |
| 152 | * the port range. |
| 153 | */ |
| 154 | static int |
| 155 | pcb_getports(struct inpcb_hdr *inp_hdr, uint16_t *lastport, |
| 156 | uint16_t *mymin, uint16_t *mymax, uint16_t **pnext_ephemeral, int algo) |
| 157 | { |
| 158 | struct inpcbtable * const table = inp_hdr->inph_table; |
| 159 | struct socket *so; |
| 160 | int portalgo_proto; |
| 161 | int portalgo_af; |
| 162 | int portalgo_range; |
| 163 | |
| 164 | so = inp_hdr->inph_socket; |
| 165 | switch (so->so_type) { |
| 166 | case SOCK_DGRAM: /* UDP or DCCP */ |
| 167 | case SOCK_CONN_DGRAM: |
| 168 | portalgo_proto = PORTALGO_UDP; |
| 169 | break; |
| 170 | case SOCK_STREAM: /* TCP or SCTP */ |
| 171 | portalgo_proto = PORTALGO_TCP; |
| 172 | break; |
| 173 | default: |
| 174 | return EPFNOSUPPORT; |
| 175 | } |
| 176 | |
| 177 | switch (inp_hdr->inph_af) { |
| 178 | #ifdef INET |
| 179 | case AF_INET: { |
| 180 | struct inpcb *inp = (struct inpcb *)(void *)inp_hdr; |
| 181 | |
| 182 | portalgo_af = PORTALGO_IPV4; |
| 183 | if (inp->inp_flags & INP_LOWPORT) { |
| 184 | *mymin = lowportmin; |
| 185 | *mymax = lowportmax; |
| 186 | *lastport = table->inpt_lastlow; |
| 187 | portalgo_range = PORTALGO_LOWPORT; |
| 188 | } else { |
| 189 | *mymin = anonportmin; |
| 190 | *mymax = anonportmax; |
| 191 | *lastport = table->inpt_lastport; |
| 192 | portalgo_range = PORTALGO_HIGHPORT; |
| 193 | } |
| 194 | break; |
| 195 | } |
| 196 | #endif |
| 197 | #ifdef INET6 |
| 198 | case AF_INET6: { |
| 199 | struct in6pcb *in6p = (struct in6pcb *)(void *)inp_hdr; |
| 200 | |
| 201 | portalgo_af = PORTALGO_IPV6; |
| 202 | if (in6p->in6p_flags & IN6P_LOWPORT) { |
| 203 | *mymin = ip6_lowportmin; |
| 204 | *mymax = ip6_lowportmax; |
| 205 | *lastport = table->inpt_lastlow; |
| 206 | portalgo_range = PORTALGO_LOWPORT; |
| 207 | } else { |
| 208 | *mymin = ip6_anonportmin; |
| 209 | *mymax = ip6_anonportmax; |
| 210 | *lastport = table->inpt_lastport; |
| 211 | portalgo_range = PORTALGO_HIGHPORT; |
| 212 | } |
| 213 | break; |
| 214 | } |
| 215 | #endif |
| 216 | default: |
| 217 | return EAFNOSUPPORT; |
| 218 | } |
| 219 | |
| 220 | if (*mymin > *mymax) { /* sanity check */ |
| 221 | u_int16_t swp; |
| 222 | |
| 223 | swp = *mymin; |
| 224 | *mymin = *mymax; |
| 225 | *mymax = swp; |
| 226 | } |
| 227 | |
| 228 | DPRINTF("%s mymin:%d mymax:%d lastport:%d\n" , __func__, |
| 229 | *mymin, *mymax, *lastport); |
| 230 | |
| 231 | *pnext_ephemeral = &portalgo_next_ephemeral[portalgo_proto] |
| 232 | [portalgo_af][portalgo_range][algo]; |
| 233 | |
| 234 | DPRINTF("%s portalgo_proto:%d portalgo_af:%d portalgo_range:%d\n" , |
| 235 | __func__, portalgo_proto, portalgo_af, portalgo_range); |
| 236 | return 0; |
| 237 | } |
| 238 | |
| 239 | /* |
| 240 | * Check whether the port picked by the port randomizer is available |
| 241 | * and whether KAUTH approves of our choice. This part of the code |
| 242 | * shamelessly copied from in_pcb.c. |
| 243 | */ |
| 244 | static bool |
| 245 | check_suitable_port(uint16_t port, struct inpcb_hdr *inp_hdr, kauth_cred_t cred) |
| 246 | { |
| 247 | struct inpcbtable * const table = inp_hdr->inph_table; |
| 248 | #ifdef INET |
| 249 | vestigial_inpcb_t vestigial; |
| 250 | #endif |
| 251 | int error; |
| 252 | #ifdef INET6 |
| 253 | struct socket *so; |
| 254 | int wild = 0; |
| 255 | #endif |
| 256 | |
| 257 | DPRINTF("%s called for argument %d\n" , __func__, port); |
| 258 | |
| 259 | switch (inp_hdr->inph_af) { |
| 260 | #ifdef INET |
| 261 | case AF_INET: { /* IPv4 */ |
| 262 | struct inpcb *inp = (struct inpcb *)(void *)inp_hdr; |
| 263 | struct inpcb *pcb; |
| 264 | struct sockaddr_in sin; |
| 265 | |
| 266 | if (__BITMAP_ISSET(port, &inet4_reserve)) |
| 267 | return false; |
| 268 | |
| 269 | sin.sin_addr = inp->inp_laddr; |
| 270 | pcb = in_pcblookup_port(table, sin.sin_addr, htons(port), 1, |
| 271 | &vestigial); |
| 272 | |
| 273 | DPRINTF("%s in_pcblookup_port returned %p and " |
| 274 | "vestigial.valid %d\n" , |
| 275 | __func__, pcb, vestigial.valid); |
| 276 | |
| 277 | if ((!pcb) && (!vestigial.valid)) { |
| 278 | enum kauth_network_req req; |
| 279 | |
| 280 | /* We have a free port. Check with the secmodel. */ |
| 281 | if (inp->inp_flags & INP_LOWPORT) { |
| 282 | #ifndef IPNOPRIVPORTS |
| 283 | req = KAUTH_REQ_NETWORK_BIND_PRIVPORT; |
| 284 | #else |
| 285 | req = KAUTH_REQ_NETWORK_BIND_PORT; |
| 286 | #endif |
| 287 | } else |
| 288 | req = KAUTH_REQ_NETWORK_BIND_PORT; |
| 289 | |
| 290 | sin.sin_port = port; |
| 291 | error = kauth_authorize_network(cred, |
| 292 | KAUTH_NETWORK_BIND, |
| 293 | req, inp->inp_socket, &sin, NULL); |
| 294 | DPRINTF("%s kauth_authorize_network returned %d\n" , |
| 295 | __func__, error); |
| 296 | |
| 297 | if (error == 0) { |
| 298 | DPRINTF("%s port approved\n" , __func__); |
| 299 | return true; /* KAUTH agrees */ |
| 300 | } |
| 301 | } |
| 302 | break; |
| 303 | } |
| 304 | #endif |
| 305 | #ifdef INET6 |
| 306 | case AF_INET6: { /* IPv6 */ |
| 307 | struct in6pcb *in6p = (struct in6pcb *)(void *)inp_hdr; |
| 308 | struct sockaddr_in6 sin6; |
| 309 | void *t; |
| 310 | |
| 311 | if (__BITMAP_ISSET(port, &inet6_reserve)) |
| 312 | return false; |
| 313 | |
| 314 | sin6.sin6_addr = in6p->in6p_laddr; |
| 315 | so = in6p->in6p_socket; |
| 316 | |
| 317 | /* XXX: this is redundant when called from in6_pcbbind */ |
| 318 | if ((so->so_options & (SO_REUSEADDR|SO_REUSEPORT)) == 0 && |
| 319 | ((so->so_proto->pr_flags & PR_CONNREQUIRED) == 0 || |
| 320 | (so->so_options & SO_ACCEPTCONN) == 0)) |
| 321 | wild = 1; |
| 322 | |
| 323 | #ifdef INET |
| 324 | if (IN6_IS_ADDR_V4MAPPED(&sin6.sin6_addr)) { |
| 325 | t = in_pcblookup_port(table, |
| 326 | *(struct in_addr *)&sin6.sin6_addr.s6_addr32[3], |
| 327 | htons(port), wild, &vestigial); |
| 328 | if (!t && vestigial.valid) { |
| 329 | DPRINTF("%s in_pcblookup_port returned " |
| 330 | "a result\n" , __func__); |
| 331 | return false; |
| 332 | } |
| 333 | } else |
| 334 | #endif |
| 335 | { |
| 336 | t = in6_pcblookup_port(table, &sin6.sin6_addr, |
| 337 | htons(port), wild, &vestigial); |
| 338 | if (!t && vestigial.valid) { |
| 339 | DPRINTF("%s in6_pcblookup_port returned " |
| 340 | "a result\n" , __func__); |
| 341 | return false; |
| 342 | } |
| 343 | } |
| 344 | if (t == NULL) { |
| 345 | enum kauth_network_req req; |
| 346 | |
| 347 | /* We have a free port. Check with the secmodel. */ |
| 348 | if (in6p->in6p_flags & IN6P_LOWPORT) { |
| 349 | #ifndef IPNOPRIVPORTS |
| 350 | req = KAUTH_REQ_NETWORK_BIND_PRIVPORT; |
| 351 | #else |
| 352 | req = KAUTH_REQ_NETWORK_BIND_PORT; |
| 353 | #endif |
| 354 | } else { |
| 355 | req = KAUTH_REQ_NETWORK_BIND_PORT; |
| 356 | } |
| 357 | |
| 358 | sin6.sin6_port = port; |
| 359 | error = kauth_authorize_network(cred, |
| 360 | KAUTH_NETWORK_BIND, req, so, &sin6, NULL); |
| 361 | if (error) { |
| 362 | /* Secmodel says no. Keep looking. */ |
| 363 | DPRINTF("%s secmodel says no\n" , __func__); |
| 364 | return false; |
| 365 | } |
| 366 | DPRINTF("%s port approved\n" , __func__); |
| 367 | return true; |
| 368 | } |
| 369 | break; |
| 370 | } |
| 371 | #endif |
| 372 | default: |
| 373 | DPRINTF("%s unknown address family\n" , __func__); |
| 374 | return false; |
| 375 | } |
| 376 | return false; |
| 377 | } |
| 378 | |
| 379 | /* This is the default BSD algorithm, as described in RFC 6056 */ |
| 380 | static int |
| 381 | algo_bsd(int algo, uint16_t *port, struct inpcb_hdr *inp_hdr, kauth_cred_t cred) |
| 382 | { |
| 383 | uint16_t count; |
| 384 | uint16_t mymin, mymax, lastport; |
| 385 | uint16_t *next_ephemeral; |
| 386 | int error; |
| 387 | |
| 388 | DPRINTF("%s called\n" , __func__); |
| 389 | error = pcb_getports(inp_hdr, &lastport, &mymin, &mymax, |
| 390 | &next_ephemeral, algo); |
| 391 | if (error) |
| 392 | return error; |
| 393 | count = mymax - mymin + 1; |
| 394 | do { |
| 395 | uint16_t myport = *next_ephemeral; |
| 396 | |
| 397 | if (myport < mymin || mymax < myport) |
| 398 | myport = mymax; |
| 399 | *next_ephemeral = myport - 1; |
| 400 | if (check_suitable_port(myport, inp_hdr, cred)) { |
| 401 | *port = myport; |
| 402 | DPRINTF("%s returning port %d\n" , __func__, *port); |
| 403 | return 0; |
| 404 | } |
| 405 | count--; |
| 406 | } while (count > 0); |
| 407 | |
| 408 | DPRINTF("%s returning EAGAIN\n" , __func__); |
| 409 | return EAGAIN; |
| 410 | } |
| 411 | |
| 412 | /* |
| 413 | * The straightforward algorithm that increments the port number |
| 414 | * by a random amount. |
| 415 | */ |
| 416 | static int |
| 417 | algo_random_start(int algo, uint16_t *port, struct inpcb_hdr *inp_hdr, |
| 418 | kauth_cred_t cred) |
| 419 | { |
| 420 | uint16_t count, num_ephemeral; |
| 421 | uint16_t mymin, mymax, lastport; |
| 422 | uint16_t *next_ephemeral; |
| 423 | int error; |
| 424 | |
| 425 | DPRINTF("%s called\n" , __func__); |
| 426 | |
| 427 | error = pcb_getports(inp_hdr, &lastport, &mymin, &mymax, |
| 428 | &next_ephemeral, algo); |
| 429 | if (error) |
| 430 | return error; |
| 431 | |
| 432 | num_ephemeral = mymax - mymin + 1; |
| 433 | |
| 434 | DPRINTF("num_ephemeral: %u\n" , num_ephemeral); |
| 435 | |
| 436 | *next_ephemeral = mymin + (cprng_fast32() % num_ephemeral); |
| 437 | |
| 438 | DPRINTF("next_ephemeral initially: %u\n" , *next_ephemeral); |
| 439 | |
| 440 | count = num_ephemeral; |
| 441 | |
| 442 | do { |
| 443 | if (check_suitable_port(*next_ephemeral, inp_hdr, cred)) { |
| 444 | *port = *next_ephemeral; |
| 445 | DPRINTF("%s returning port %d\n" , __func__, *port); |
| 446 | return 0; |
| 447 | } |
| 448 | if (*next_ephemeral == mymax) { |
| 449 | *next_ephemeral = mymin; |
| 450 | } else |
| 451 | (*next_ephemeral)++; |
| 452 | |
| 453 | count--; |
| 454 | |
| 455 | |
| 456 | DPRINTF("next_ephemeral: %u count: %u\n" , *next_ephemeral, |
| 457 | count); |
| 458 | |
| 459 | } while (count > 0); |
| 460 | |
| 461 | DPRINTF("%s returning EINVAL\n" , __func__); |
| 462 | |
| 463 | return EINVAL; |
| 464 | } |
| 465 | |
| 466 | /* |
| 467 | * Since there is no state kept on the ports tried, we might actually |
| 468 | * give up before exhausting the free ports. |
| 469 | */ |
| 470 | static int |
| 471 | algo_random_pick(int algo, uint16_t *port, struct inpcb_hdr *inp_hdr, |
| 472 | kauth_cred_t cred) |
| 473 | { |
| 474 | uint16_t count, num_ephemeral; |
| 475 | uint16_t mymin, mymax, lastport; |
| 476 | uint16_t *next_ephemeral; |
| 477 | int error; |
| 478 | |
| 479 | DPRINTF("%s called\n" , __func__); |
| 480 | |
| 481 | error = pcb_getports(inp_hdr, &lastport, &mymin, &mymax, |
| 482 | &next_ephemeral, algo); |
| 483 | if (error) |
| 484 | return error; |
| 485 | |
| 486 | num_ephemeral = mymax - mymin + 1; |
| 487 | |
| 488 | DPRINTF("num_ephemeral: %u\n" , num_ephemeral); |
| 489 | *next_ephemeral = mymin + (cprng_fast32() % num_ephemeral); |
| 490 | |
| 491 | DPRINTF("next_ephemeral initially: %u\n" , *next_ephemeral); |
| 492 | |
| 493 | count = num_ephemeral; |
| 494 | |
| 495 | do { |
| 496 | if (check_suitable_port(*next_ephemeral, inp_hdr, cred)) { |
| 497 | *port = *next_ephemeral; |
| 498 | DPRINTF("%s returning port %d\n" , __func__, *port); |
| 499 | return 0; |
| 500 | } |
| 501 | *next_ephemeral = mymin + |
| 502 | (cprng_fast32() % num_ephemeral); |
| 503 | |
| 504 | count--; |
| 505 | |
| 506 | DPRINTF("next_ephemeral: %u count: %u\n" , |
| 507 | *next_ephemeral, count); |
| 508 | } while (count > 0); |
| 509 | |
| 510 | DPRINTF("%s returning EINVAL\n" , __func__); |
| 511 | |
| 512 | return EINVAL; |
| 513 | } |
| 514 | |
| 515 | /* This is the implementation from FreeBSD, with tweaks */ |
| 516 | static uint16_t |
| 517 | Fhash(const struct inpcb_hdr *inp_hdr) |
| 518 | { |
| 519 | MD5_CTX f_ctx; |
| 520 | uint32_t Ff[4]; |
| 521 | uint32_t secret_f[4]; |
| 522 | uint32_t offset; |
| 523 | uint16_t soffset[2]; |
| 524 | |
| 525 | cprng_fast(secret_f, sizeof(secret_f)); |
| 526 | |
| 527 | MD5Init(&f_ctx); |
| 528 | switch (inp_hdr->inph_af) { |
| 529 | #ifdef INET |
| 530 | case AF_INET: { |
| 531 | const struct inpcb *inp = |
| 532 | (const struct inpcb *)(const void *)inp_hdr; |
| 533 | MD5Update(&f_ctx, (const u_char *)&inp->inp_laddr, |
| 534 | sizeof(inp->inp_laddr)); |
| 535 | MD5Update(&f_ctx, (const u_char *)&inp->inp_faddr, |
| 536 | sizeof(inp->inp_faddr)); |
| 537 | MD5Update(&f_ctx, (const u_char *)&inp->inp_fport, |
| 538 | sizeof(inp->inp_fport)); |
| 539 | break; |
| 540 | } |
| 541 | #endif |
| 542 | #ifdef INET6 |
| 543 | case AF_INET6: { |
| 544 | const struct in6pcb *in6p = |
| 545 | (const struct in6pcb *)(const void *)inp_hdr; |
| 546 | MD5Update(&f_ctx, (const u_char *)&in6p->in6p_laddr, |
| 547 | sizeof(in6p->in6p_laddr)); |
| 548 | MD5Update(&f_ctx, (const u_char *)&in6p->in6p_faddr, |
| 549 | sizeof(in6p->in6p_faddr)); |
| 550 | MD5Update(&f_ctx, (const u_char *)&in6p->in6p_fport, |
| 551 | sizeof(in6p->in6p_fport)); |
| 552 | break; |
| 553 | } |
| 554 | #endif |
| 555 | default: |
| 556 | break; |
| 557 | } |
| 558 | MD5Update(&f_ctx, (const u_char *)secret_f, sizeof(secret_f)); |
| 559 | MD5Final((u_char *)&Ff, &f_ctx); |
| 560 | |
| 561 | offset = (Ff[0] ^ Ff[1]) ^ (Ff[2] ^ Ff[3]); |
| 562 | |
| 563 | memcpy(&soffset, &offset, sizeof(soffset)); |
| 564 | |
| 565 | return soffset[0] ^ soffset[1]; |
| 566 | } |
| 567 | |
| 568 | /* |
| 569 | * Checks whether the tuple is complete. If not, marks the pcb for |
| 570 | * late binding. |
| 571 | */ |
| 572 | static bool |
| 573 | iscompletetuple(struct inpcb_hdr *inp_hdr) |
| 574 | { |
| 575 | #ifdef INET6 |
| 576 | struct in6pcb *in6p; |
| 577 | #endif |
| 578 | |
| 579 | switch (inp_hdr->inph_af) { |
| 580 | #ifdef INET |
| 581 | case AF_INET: { |
| 582 | struct inpcb *inp = (struct inpcb *)(void *)inp_hdr; |
| 583 | if (inp->inp_fport == 0 || in_nullhost(inp->inp_faddr)) { |
| 584 | DPRINTF("%s fport or faddr missing, delaying port " |
| 585 | "to connect/send\n" , __func__); |
| 586 | inp->inp_bindportonsend = true; |
| 587 | return false; |
| 588 | } else { |
| 589 | inp->inp_bindportonsend = false; |
| 590 | } |
| 591 | break; |
| 592 | } |
| 593 | #endif |
| 594 | #ifdef INET6 |
| 595 | case AF_INET6: { |
| 596 | in6p = (struct in6pcb *)(void *)inp_hdr; |
| 597 | if (in6p->in6p_fport == 0 || memcmp(&in6p->in6p_faddr, |
| 598 | &in6addr_any, sizeof(in6p->in6p_faddr)) == 0) { |
| 599 | DPRINTF("%s fport or faddr missing, delaying port " |
| 600 | "to connect/send\n" , __func__); |
| 601 | in6p->in6p_bindportonsend = true; |
| 602 | return false; |
| 603 | } else { |
| 604 | in6p->in6p_bindportonsend = false; |
| 605 | } |
| 606 | break; |
| 607 | } |
| 608 | #endif |
| 609 | default: |
| 610 | DPRINTF("%s incorrect address family\n" , __func__); |
| 611 | return false; |
| 612 | } |
| 613 | |
| 614 | return true; |
| 615 | } |
| 616 | |
| 617 | static int |
| 618 | algo_hash(int algo, uint16_t *port, struct inpcb_hdr *inp_hdr, |
| 619 | kauth_cred_t cred) |
| 620 | { |
| 621 | uint16_t count, num_ephemeral; |
| 622 | uint16_t mymin, mymax, lastport; |
| 623 | uint16_t *next_ephemeral; |
| 624 | uint16_t offset, myport; |
| 625 | int error; |
| 626 | |
| 627 | DPRINTF("%s called\n" , __func__); |
| 628 | |
| 629 | error = pcb_getports(inp_hdr, &lastport, &mymin, &mymax, |
| 630 | &next_ephemeral, algo); |
| 631 | if (error) |
| 632 | return error; |
| 633 | |
| 634 | if (!iscompletetuple(inp_hdr)) { |
| 635 | *port = 0; |
| 636 | return 0; |
| 637 | } |
| 638 | |
| 639 | /* Ephemeral port selection function */ |
| 640 | num_ephemeral = mymax - mymin + 1; |
| 641 | |
| 642 | DPRINTF("num_ephemeral: %d\n" , num_ephemeral); |
| 643 | |
| 644 | offset = Fhash(inp_hdr); |
| 645 | |
| 646 | count = num_ephemeral; |
| 647 | do { |
| 648 | myport = mymin + (*next_ephemeral + offset) |
| 649 | % num_ephemeral; |
| 650 | |
| 651 | (*next_ephemeral)++; |
| 652 | |
| 653 | if (check_suitable_port(myport, inp_hdr, cred)) { |
| 654 | *port = myport; |
| 655 | DPRINTF("%s returning port %d\n" , __func__, *port); |
| 656 | return 0; |
| 657 | } |
| 658 | count--; |
| 659 | } while (count > 0); |
| 660 | |
| 661 | DPRINTF("%s returning EINVAL\n" , __func__); |
| 662 | |
| 663 | return EINVAL; |
| 664 | } |
| 665 | |
| 666 | static int |
| 667 | algo_doublehash(int algo, uint16_t *port, struct inpcb_hdr *inp_hdr, |
| 668 | kauth_cred_t cred) |
| 669 | { |
| 670 | uint16_t count, num_ephemeral; |
| 671 | uint16_t mymin, mymax, lastport; |
| 672 | uint16_t *next_ephemeral; |
| 673 | uint16_t offset, myport; |
| 674 | static uint16_t dhtable[8]; |
| 675 | size_t idx; |
| 676 | int error; |
| 677 | |
| 678 | DPRINTF("%s called\n" , __func__); |
| 679 | |
| 680 | error = pcb_getports(inp_hdr, &lastport, &mymin, &mymax, |
| 681 | &next_ephemeral, algo); |
| 682 | if (error) |
| 683 | return error; |
| 684 | |
| 685 | if (!iscompletetuple(inp_hdr)) { |
| 686 | *port = 0; |
| 687 | return 0; |
| 688 | } |
| 689 | /* first time initialization */ |
| 690 | if (dhtable[0] == 0) |
| 691 | for (size_t i = 0; i < __arraycount(dhtable); i++) |
| 692 | dhtable[i] = cprng_fast32() & 0xffff; |
| 693 | |
| 694 | /* Ephemeral port selection function */ |
| 695 | num_ephemeral = mymax - mymin + 1; |
| 696 | offset = Fhash(inp_hdr); |
| 697 | idx = Fhash(inp_hdr) % __arraycount(dhtable); /* G */ |
| 698 | count = num_ephemeral; |
| 699 | |
| 700 | do { |
| 701 | myport = mymin + (offset + dhtable[idx]) |
| 702 | % num_ephemeral; |
| 703 | dhtable[idx]++; |
| 704 | |
| 705 | if (check_suitable_port(myport, inp_hdr, cred)) { |
| 706 | *port = myport; |
| 707 | DPRINTF("%s returning port %d\n" , __func__, *port); |
| 708 | return 0; |
| 709 | } |
| 710 | count--; |
| 711 | |
| 712 | } while (count > 0); |
| 713 | |
| 714 | DPRINTF("%s returning EINVAL\n" , __func__); |
| 715 | |
| 716 | return EINVAL; |
| 717 | } |
| 718 | |
| 719 | static int |
| 720 | algo_randinc(int algo, uint16_t *port, struct inpcb_hdr *inp_hdr, |
| 721 | kauth_cred_t cred) |
| 722 | { |
| 723 | static const uint16_t N = 500; /* Determines the trade-off */ |
| 724 | uint16_t count, num_ephemeral; |
| 725 | uint16_t mymin, mymax, lastport; |
| 726 | uint16_t *next_ephemeral; |
| 727 | uint16_t myport; |
| 728 | int error; |
| 729 | |
| 730 | DPRINTF("%s called\n" , __func__); |
| 731 | |
| 732 | error = pcb_getports(inp_hdr, &lastport, &mymin, &mymax, |
| 733 | &next_ephemeral, algo); |
| 734 | if (error) |
| 735 | return error; |
| 736 | |
| 737 | if (*next_ephemeral == 0) |
| 738 | *next_ephemeral = cprng_fast32() & 0xffff; |
| 739 | |
| 740 | /* Ephemeral port selection function */ |
| 741 | num_ephemeral = mymax - mymin + 1; |
| 742 | |
| 743 | count = num_ephemeral; |
| 744 | do { |
| 745 | *next_ephemeral = *next_ephemeral + |
| 746 | (cprng_fast32() % N) + 1; |
| 747 | myport = mymin + |
| 748 | (*next_ephemeral % num_ephemeral); |
| 749 | |
| 750 | if (check_suitable_port(myport, inp_hdr, cred)) { |
| 751 | *port = myport; |
| 752 | DPRINTF("%s returning port %d\n" , __func__, *port); |
| 753 | return 0; |
| 754 | } |
| 755 | count--; |
| 756 | } while (count > 0); |
| 757 | |
| 758 | return EINVAL; |
| 759 | } |
| 760 | |
| 761 | /* The generic function called in order to pick a port. */ |
| 762 | int |
| 763 | portalgo_randport(uint16_t *port, struct inpcb_hdr *inp_hdr, kauth_cred_t cred) |
| 764 | { |
| 765 | int algo, error; |
| 766 | uint16_t lport; |
| 767 | int default_algo; |
| 768 | |
| 769 | DPRINTF("%s called\n" , __func__); |
| 770 | |
| 771 | if (inp_hdr->inph_portalgo == PORTALGO_DEFAULT) { |
| 772 | switch (inp_hdr->inph_af) { |
| 773 | #ifdef INET |
| 774 | case AF_INET: |
| 775 | default_algo = inet4_portalgo; |
| 776 | break; |
| 777 | #endif |
| 778 | #ifdef INET6 |
| 779 | case AF_INET6: |
| 780 | default_algo = inet6_portalgo; |
| 781 | break; |
| 782 | #endif |
| 783 | default: |
| 784 | return EINVAL; |
| 785 | } |
| 786 | |
| 787 | if (default_algo == PORTALGO_DEFAULT) |
| 788 | algo = PORTALGO_BSD; |
| 789 | else |
| 790 | algo = default_algo; |
| 791 | } |
| 792 | else /* socket specifies the algorithm */ |
| 793 | algo = inp_hdr->inph_portalgo; |
| 794 | |
| 795 | KASSERT(algo >= 0); |
| 796 | KASSERT(algo < NALGOS); |
| 797 | |
| 798 | switch (inp_hdr->inph_af) { |
| 799 | #ifdef INET |
| 800 | case AF_INET: { |
| 801 | char buf[INET_ADDRSTRLEN]; |
| 802 | struct inpcb *inp = (struct inpcb *)(void *)inp_hdr; |
| 803 | DPRINTF("local addr: %s\n" , IN_PRINT(buf, &inp->inp_laddr)); |
| 804 | DPRINTF("local port: %d\n" , inp->inp_lport); |
| 805 | DPRINTF("foreign addr: %s\n" , IN_PRINT(buf, &inp->inp_faddr)); |
| 806 | DPRINTF("foreign port: %d\n" , inp->inp_fport); |
| 807 | break; |
| 808 | } |
| 809 | #endif |
| 810 | #ifdef INET6 |
| 811 | case AF_INET6: { |
| 812 | char buf[INET6_ADDRSTRLEN]; |
| 813 | struct in6pcb *in6p = (struct in6pcb *)(void *)inp_hdr; |
| 814 | |
| 815 | DPRINTF("local addr: %s\n" , IN6_PRINT(buf, &in6p->in6p_laddr)); |
| 816 | DPRINTF("local port: %d\n" , in6p->in6p_lport); |
| 817 | DPRINTF("foreign addr: %s\n" , IN6_PRINT(buf, |
| 818 | &in6p->in6p_laddr)); |
| 819 | DPRINTF("foreign port: %d\n" , in6p->in6p_fport); |
| 820 | break; |
| 821 | } |
| 822 | #endif |
| 823 | default: |
| 824 | break; |
| 825 | } |
| 826 | |
| 827 | DPRINTF("%s portalgo = %d\n" , __func__, algo); |
| 828 | |
| 829 | error = (*algos[algo].func)(algo, &lport, inp_hdr, cred); |
| 830 | if (error == 0) { |
| 831 | *port = lport; |
| 832 | } else if (error != EAGAIN) { |
| 833 | uint16_t lastport, mymin, mymax, *pnext_ephemeral; |
| 834 | |
| 835 | error = pcb_getports(inp_hdr, &lastport, &mymin, |
| 836 | &mymax, &pnext_ephemeral, algo); |
| 837 | if (error) |
| 838 | return error; |
| 839 | *port = lastport - 1; |
| 840 | } |
| 841 | return error; |
| 842 | } |
| 843 | |
| 844 | /* Sets the algorithm to be used globally */ |
| 845 | static int |
| 846 | portalgo_algo_name_select(const char *name, int *algo) |
| 847 | { |
| 848 | size_t ai; |
| 849 | |
| 850 | DPRINTF("%s called\n" , __func__); |
| 851 | |
| 852 | for (ai = 0; ai < NALGOS; ai++) |
| 853 | if (strcmp(algos[ai].name, name) == 0) { |
| 854 | DPRINTF("%s: found idx %zu\n" , __func__, ai); |
| 855 | *algo = ai; |
| 856 | return 0; |
| 857 | } |
| 858 | return EINVAL; |
| 859 | } |
| 860 | |
| 861 | /* Sets the algorithm to be used by the pcb inp. */ |
| 862 | int |
| 863 | portalgo_algo_index_select(struct inpcb_hdr *inp, int algo) |
| 864 | { |
| 865 | |
| 866 | DPRINTF("%s called with algo %d for pcb %p\n" , __func__, algo, inp ); |
| 867 | |
| 868 | if ((algo < 0 || algo >= NALGOS) && |
| 869 | (algo != PORTALGO_DEFAULT)) |
| 870 | return EINVAL; |
| 871 | |
| 872 | inp->inph_portalgo = algo; |
| 873 | return 0; |
| 874 | } |
| 875 | |
| 876 | /* |
| 877 | * The sysctl hook that is supposed to check that we are picking one |
| 878 | * of the valid algorithms. |
| 879 | */ |
| 880 | static int |
| 881 | sysctl_portalgo_selected(SYSCTLFN_ARGS, int *algo) |
| 882 | { |
| 883 | struct sysctlnode node; |
| 884 | int error; |
| 885 | char newalgo[PORTALGO_MAXLEN]; |
| 886 | |
| 887 | DPRINTF("%s called\n" , __func__); |
| 888 | |
| 889 | strlcpy(newalgo, algos[*algo].name, sizeof(newalgo)); |
| 890 | |
| 891 | node = *rnode; |
| 892 | node.sysctl_data = newalgo; |
| 893 | node.sysctl_size = sizeof(newalgo); |
| 894 | |
| 895 | error = sysctl_lookup(SYSCTLFN_CALL(&node)); |
| 896 | |
| 897 | DPRINTF("newalgo: %s\n" , newalgo); |
| 898 | |
| 899 | if (error || newp == NULL || |
| 900 | strncmp(newalgo, algos[*algo].name, sizeof(newalgo)) == 0) |
| 901 | return error; |
| 902 | |
| 903 | #ifdef KAUTH_NETWORK_SOCKET_PORT_RANDOMIZE |
| 904 | if (l != NULL && (error = kauth_authorize_system(l->l_cred, |
| 905 | KAUTH_NETWORK_SOCKET, KAUTH_NETWORK_SOCKET_PORT_RANDOMIZE, newname, |
| 906 | NULL, NULL)) != 0) |
| 907 | return error; |
| 908 | #endif |
| 909 | |
| 910 | mutex_enter(softnet_lock); |
| 911 | error = portalgo_algo_name_select(newalgo, algo); |
| 912 | mutex_exit(softnet_lock); |
| 913 | return error; |
| 914 | } |
| 915 | |
| 916 | static int |
| 917 | sysctl_portalgo_reserve(SYSCTLFN_ARGS, bitmap *bt) |
| 918 | { |
| 919 | struct sysctlnode node; |
| 920 | int error; |
| 921 | |
| 922 | DPRINTF("%s called\n" , __func__); |
| 923 | |
| 924 | node = *rnode; |
| 925 | node.sysctl_data = bt; |
| 926 | node.sysctl_size = sizeof(*bt); |
| 927 | |
| 928 | error = sysctl_lookup(SYSCTLFN_CALL(&node)); |
| 929 | |
| 930 | if (error || newp == NULL) |
| 931 | return error; |
| 932 | |
| 933 | #ifdef KAUTH_NETWORK_SOCKET_PORT_RESERVE |
| 934 | if (l != NULL && (error = kauth_authorize_system(l->l_cred, |
| 935 | KAUTH_NETWORK_SOCKET, KAUTH_NETWORK_SOCKET_PORT_RESERVE, bt, |
| 936 | NULL, NULL)) != 0) |
| 937 | return error; |
| 938 | #endif |
| 939 | return error; |
| 940 | } |
| 941 | |
| 942 | #ifdef INET |
| 943 | /* |
| 944 | * The sysctl hook that is supposed to check that we are picking one |
| 945 | * of the valid algorithms. |
| 946 | */ |
| 947 | int |
| 948 | sysctl_portalgo_selected4(SYSCTLFN_ARGS) |
| 949 | { |
| 950 | |
| 951 | return sysctl_portalgo_selected(SYSCTLFN_CALL(rnode), &inet4_portalgo); |
| 952 | } |
| 953 | |
| 954 | int |
| 955 | sysctl_portalgo_reserve4(SYSCTLFN_ARGS) |
| 956 | { |
| 957 | |
| 958 | return sysctl_portalgo_reserve(SYSCTLFN_CALL(rnode), &inet4_reserve); |
| 959 | } |
| 960 | #endif |
| 961 | |
| 962 | #ifdef INET6 |
| 963 | int |
| 964 | sysctl_portalgo_selected6(SYSCTLFN_ARGS) |
| 965 | { |
| 966 | |
| 967 | return sysctl_portalgo_selected(SYSCTLFN_CALL(rnode), &inet6_portalgo); |
| 968 | } |
| 969 | |
| 970 | int |
| 971 | sysctl_portalgo_reserve6(SYSCTLFN_ARGS) |
| 972 | { |
| 973 | return sysctl_portalgo_reserve(SYSCTLFN_CALL(rnode), &inet6_reserve); |
| 974 | } |
| 975 | #endif |
| 976 | |
| 977 | /* |
| 978 | * The sysctl hook that returns the available |
| 979 | * algorithms. |
| 980 | */ |
| 981 | int |
| 982 | sysctl_portalgo_available(SYSCTLFN_ARGS) |
| 983 | { |
| 984 | size_t ai, len = 0; |
| 985 | struct sysctlnode node; |
| 986 | char availalgo[NALGOS * PORTALGO_MAXLEN]; |
| 987 | |
| 988 | DPRINTF("%s called\n" , __func__); |
| 989 | |
| 990 | availalgo[0] = '\0'; |
| 991 | |
| 992 | for (ai = 0; ai < NALGOS; ai++) { |
| 993 | len = strlcat(availalgo, algos[ai].name, sizeof(availalgo)); |
| 994 | if (ai < NALGOS - 1) |
| 995 | strlcat(availalgo, " " , sizeof(availalgo)); |
| 996 | } |
| 997 | |
| 998 | DPRINTF("available algos: %s\n" , availalgo); |
| 999 | |
| 1000 | node = *rnode; |
| 1001 | node.sysctl_data = availalgo; |
| 1002 | node.sysctl_size = len; |
| 1003 | |
| 1004 | return sysctl_lookup(SYSCTLFN_CALL(&node)); |
| 1005 | } |
| 1006 | |