| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * Make programs use Unix-domain sockets instead of IP |
| 4 | * |
| 5 | * (c) 2008 Straylight/Edgeware |
| 6 | */ |
| 7 | |
| 8 | /*----- Licensing notice --------------------------------------------------* |
| 9 | * |
| 10 | * This file is part of the preload-hacks package. |
| 11 | * |
| 12 | * Preload-hacks are free software; you can redistribute it and/or modify |
| 13 | * them under the terms of the GNU General Public License as published by |
| 14 | * the Free Software Foundation; either version 2 of the License, or (at |
| 15 | * your option) any later version. |
| 16 | * |
| 17 | * Preload-hacks are distributed in the hope that it will be useful, but |
| 18 | * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY |
| 19 | * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 20 | * for more details. |
| 21 | * |
| 22 | * You should have received a copy of the GNU General Public License along |
| 23 | * with preload-hacks; if not, write to the Free Software Foundation, Inc., |
| 24 | * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 25 | */ |
| 26 | |
| 27 | #define _GNU_SOURCE |
| 28 | #undef sun |
| 29 | #undef SUN |
| 30 | #define DEBUG |
| 31 | |
| 32 | /*----- Header files ------------------------------------------------------*/ |
| 33 | |
| 34 | #include <assert.h> |
| 35 | #include <ctype.h> |
| 36 | #include <errno.h> |
| 37 | #include <stdarg.h> |
| 38 | #include <stddef.h> |
| 39 | #include <stdio.h> |
| 40 | #include <stdlib.h> |
| 41 | |
| 42 | #include <unistd.h> |
| 43 | #include <dirent.h> |
| 44 | #include <dlfcn.h> |
| 45 | #include <fcntl.h> |
| 46 | #include <pwd.h> |
| 47 | |
| 48 | #include <sys/ioctl.h> |
| 49 | #include <sys/socket.h> |
| 50 | #include <sys/stat.h> |
| 51 | #include <sys/un.h> |
| 52 | |
| 53 | #include <netinet/in.h> |
| 54 | #include <arpa/inet.h> |
| 55 | #include <netinet/tcp.h> |
| 56 | #include <netinet/udp.h> |
| 57 | #include <ifaddrs.h> |
| 58 | #include <netdb.h> |
| 59 | |
| 60 | /*----- Data structures ---------------------------------------------------*/ |
| 61 | |
| 62 | enum { UNUSED, STALE, USED }; /* Unix socket status values */ |
| 63 | enum { WANT_FRESH, WANT_EXISTING }; /* Socket address dispositions */ |
| 64 | enum { DENY, ALLOW }; /* ACL verdicts */ |
| 65 | |
| 66 | static int address_families[] = { AF_INET, AF_INET6, -1 }; |
| 67 | |
| 68 | #define ADDRBUFSZ 64 |
| 69 | |
| 70 | /* Address representations. */ |
| 71 | typedef union ipaddr { |
| 72 | struct in_addr v4; |
| 73 | struct in6_addr v6; |
| 74 | } ipaddr; |
| 75 | |
| 76 | /* Convenient socket address hacking. */ |
| 77 | typedef union address { |
| 78 | struct sockaddr sa; |
| 79 | struct sockaddr_in sin; |
| 80 | struct sockaddr_in6 sin6; |
| 81 | } address; |
| 82 | |
| 83 | /* Access control list nodes */ |
| 84 | typedef struct aclnode { |
| 85 | struct aclnode *next; |
| 86 | int act; |
| 87 | int af; |
| 88 | ipaddr minaddr, maxaddr; |
| 89 | unsigned short minport, maxport; |
| 90 | } aclnode; |
| 91 | |
| 92 | /* Local address records */ |
| 93 | typedef struct full_ipaddr { |
| 94 | int af; |
| 95 | ipaddr addr; |
| 96 | } full_ipaddr; |
| 97 | #define MAX_LOCAL_IPADDRS 64 |
| 98 | static full_ipaddr local_ipaddrs[MAX_LOCAL_IPADDRS]; |
| 99 | static int n_local_ipaddrs; |
| 100 | |
| 101 | /* General configuration */ |
| 102 | static uid_t uid; |
| 103 | static char *sockdir = 0; |
| 104 | static int debug = 0; |
| 105 | static unsigned minautoport = 16384, maxautoport = 65536; |
| 106 | |
| 107 | /* Access control lists */ |
| 108 | static aclnode *bind_real, **bind_tail = &bind_real; |
| 109 | static aclnode *connect_real, **connect_tail = &connect_real; |
| 110 | |
| 111 | /*----- Import the real versions of functions -----------------------------*/ |
| 112 | |
| 113 | /* The list of functions to immport. */ |
| 114 | #define IMPORTS(_) \ |
| 115 | _(socket, int, (int, int, int)) \ |
| 116 | _(socketpair, int, (int, int, int, int *)) \ |
| 117 | _(connect, int, (int, const struct sockaddr *, socklen_t)) \ |
| 118 | _(bind, int, (int, const struct sockaddr *, socklen_t)) \ |
| 119 | _(accept, int, (int, struct sockaddr *, socklen_t *)) \ |
| 120 | _(getsockname, int, (int, struct sockaddr *, socklen_t *)) \ |
| 121 | _(getpeername, int, (int, struct sockaddr *, socklen_t *)) \ |
| 122 | _(getsockopt, int, (int, int, int, void *, socklen_t *)) \ |
| 123 | _(setsockopt, int, (int, int, int, const void *, socklen_t)) \ |
| 124 | _(sendto, ssize_t, (int, const void *buf, size_t, int, \ |
| 125 | const struct sockaddr *to, socklen_t tolen)) \ |
| 126 | _(recvfrom, ssize_t, (int, void *buf, size_t, int, \ |
| 127 | struct sockaddr *from, socklen_t *fromlen)) \ |
| 128 | _(sendmsg, ssize_t, (int, const struct msghdr *, int)) \ |
| 129 | _(recvmsg, ssize_t, (int, struct msghdr *, int)) \ |
| 130 | _(ioctl, int, (int, unsigned long, ...)) |
| 131 | |
| 132 | /* Function pointers to set up. */ |
| 133 | #define DECL(imp, ret, args) static ret (*real_##imp) args; |
| 134 | IMPORTS(DECL) |
| 135 | #undef DECL |
| 136 | |
| 137 | /* Import the system calls. */ |
| 138 | static void import(void) |
| 139 | { |
| 140 | #define IMPORT(imp, ret, args) \ |
| 141 | real_##imp = (ret (*)args)dlsym(RTLD_NEXT, #imp); |
| 142 | IMPORTS(IMPORT) |
| 143 | #undef IMPORT |
| 144 | } |
| 145 | |
| 146 | /*----- Utilities ---------------------------------------------------------*/ |
| 147 | |
| 148 | /* Socket address casts */ |
| 149 | #define SA(sa) ((struct sockaddr *)(sa)) |
| 150 | #define SIN(sa) ((struct sockaddr_in *)(sa)) |
| 151 | #define SIN6(sa) ((struct sockaddr_in6 *)(sa)) |
| 152 | #define SUN(sa) ((struct sockaddr_un *)(sa)) |
| 153 | |
| 154 | /* Raw bytes */ |
| 155 | #define UC(ch) ((unsigned char)(ch)) |
| 156 | |
| 157 | /* Memory allocation */ |
| 158 | #define NEW(x) ((x) = xmalloc(sizeof(*x))) |
| 159 | #define NEWV(x, n) ((x) = xmalloc(sizeof(*x) * (n))) |
| 160 | |
| 161 | /* Debugging */ |
| 162 | #ifdef DEBUG |
| 163 | # define D(body) { if (debug) { body } } |
| 164 | # define Dpid pid_t pid = debug ? getpid() : -1 |
| 165 | #else |
| 166 | # define D(body) ; |
| 167 | # define Dpid |
| 168 | #endif |
| 169 | |
| 170 | /* Preservation of error status */ |
| 171 | #define PRESERVING_ERRNO(body) do { \ |
| 172 | int _err = errno; { body } errno = _err; \ |
| 173 | } while (0) |
| 174 | |
| 175 | /* Allocate N bytes of memory; abort on failure. */ |
| 176 | static void *xmalloc(size_t n) |
| 177 | { |
| 178 | void *p; |
| 179 | if (!n) return (0); |
| 180 | if ((p = malloc(n)) == 0) { perror("malloc"); exit(127); } |
| 181 | return (p); |
| 182 | } |
| 183 | |
| 184 | /* Allocate a copy of the null-terminated string P; abort on failure. */ |
| 185 | static char *xstrdup(const char *p) |
| 186 | { |
| 187 | size_t n = strlen(p) + 1; |
| 188 | char *q = xmalloc(n); |
| 189 | memcpy(q, p, n); |
| 190 | return (q); |
| 191 | } |
| 192 | |
| 193 | /*----- Address-type hacking ----------------------------------------------*/ |
| 194 | |
| 195 | /* If M is a simple mask, i.e., consists of a sequence of zero bits followed |
| 196 | * by a sequence of one bits, then return the length of the latter sequence |
| 197 | * (which may be zero); otherwise return -1. |
| 198 | */ |
| 199 | static int simple_mask_length(unsigned long m) |
| 200 | { |
| 201 | int n = 0; |
| 202 | |
| 203 | while (m & 1) { n++; m >>= 1; } |
| 204 | return (m ? -1 : n); |
| 205 | } |
| 206 | |
| 207 | /* Answer whether AF is an interesting address family. */ |
| 208 | static int family_known_p(int af) |
| 209 | { |
| 210 | switch (af) { |
| 211 | case AF_INET: |
| 212 | case AF_INET6: |
| 213 | return (1); |
| 214 | default: |
| 215 | return (0); |
| 216 | } |
| 217 | } |
| 218 | |
| 219 | /* Return the socket address length for address family AF. */ |
| 220 | static socklen_t family_socklen(int af) |
| 221 | { |
| 222 | switch (af) { |
| 223 | case AF_INET: return (sizeof(struct sockaddr_in)); |
| 224 | case AF_INET6: return (sizeof(struct sockaddr_in6)); |
| 225 | default: abort(); |
| 226 | } |
| 227 | } |
| 228 | |
| 229 | /* Return the width of addresses of kind AF. */ |
| 230 | static int address_width(int af) |
| 231 | { |
| 232 | switch (af) { |
| 233 | case AF_INET: return 32; |
| 234 | case AF_INET6: return 128; |
| 235 | default: abort(); |
| 236 | } |
| 237 | } |
| 238 | |
| 239 | /* If addresses A and B share a common prefix then return its length; |
| 240 | * otherwise return -1. |
| 241 | */ |
| 242 | static int common_prefix_length(int af, const ipaddr *a, const ipaddr *b) |
| 243 | { |
| 244 | switch (af) { |
| 245 | case AF_INET: { |
| 246 | unsigned long aa = ntohl(a->v4.s_addr), bb = ntohl(b->v4.s_addr); |
| 247 | unsigned long m = aa^bb; |
| 248 | if ((aa&m) == 0 && (bb&m) == m) return (32 - simple_mask_length(m)); |
| 249 | else return (-1); |
| 250 | } break; |
| 251 | case AF_INET6: { |
| 252 | const uint8_t *aa = a->v6.s6_addr, *bb = b->v6.s6_addr; |
| 253 | unsigned m; |
| 254 | unsigned n; |
| 255 | int i; |
| 256 | |
| 257 | for (i = 0; i < 16 && aa[i] == bb[i]; i++); |
| 258 | n = 8*i; |
| 259 | if (i < 16) { |
| 260 | m = aa[i]^bb[i]; |
| 261 | if ((aa[i]&m) != 0 || (bb[i]&m) != m) return (-1); |
| 262 | n += 8 - simple_mask_length(m); |
| 263 | for (i++; i < 16; i++) |
| 264 | if (aa[i] || bb[i] != 0xff) return (-1); |
| 265 | } |
| 266 | return (n); |
| 267 | } break; |
| 268 | default: |
| 269 | abort(); |
| 270 | } |
| 271 | } |
| 272 | |
| 273 | /* Extract the port number (in host byte-order) from SA. */ |
| 274 | static int port_from_sockaddr(const struct sockaddr *sa) |
| 275 | { |
| 276 | switch (sa->sa_family) { |
| 277 | case AF_INET: return (ntohs(SIN(sa)->sin_port)); |
| 278 | case AF_INET6: return (ntohs(SIN6(sa)->sin6_port)); |
| 279 | default: abort(); |
| 280 | } |
| 281 | } |
| 282 | |
| 283 | /* Store the port number PORT (in host byte-order) in SA. */ |
| 284 | static void port_to_sockaddr(struct sockaddr *sa, int port) |
| 285 | { |
| 286 | switch (sa->sa_family) { |
| 287 | case AF_INET: SIN(sa)->sin_port = htons(port); break; |
| 288 | case AF_INET6: SIN6(sa)->sin6_port = htons(port); break; |
| 289 | default: abort(); |
| 290 | } |
| 291 | } |
| 292 | |
| 293 | /* Extract the address part from SA and store it in A. */ |
| 294 | static void ipaddr_from_sockaddr(ipaddr *a, const struct sockaddr *sa) |
| 295 | { |
| 296 | switch (sa->sa_family) { |
| 297 | case AF_INET: a->v4 = SIN(sa)->sin_addr; break; |
| 298 | case AF_INET6: a->v6 = SIN6(sa)->sin6_addr; break; |
| 299 | default: abort(); |
| 300 | } |
| 301 | } |
| 302 | |
| 303 | /* Copy a whole socket address about. */ |
| 304 | static void copy_sockaddr(struct sockaddr *sa_dst, |
| 305 | const struct sockaddr *sa_src) |
| 306 | { memcpy(sa_dst, sa_src, family_socklen(sa_src->sa_family)); } |
| 307 | |
| 308 | /* Answer whether two addresses are equal. */ |
| 309 | static int ipaddr_equal_p(int af, const ipaddr *a, const ipaddr *b) |
| 310 | { |
| 311 | switch (af) { |
| 312 | case AF_INET: return (a->v4.s_addr == b->v4.s_addr); |
| 313 | case AF_INET6: return (memcmp(a->v6.s6_addr, b->v6.s6_addr, 16) == 0); |
| 314 | default: abort(); |
| 315 | } |
| 316 | } |
| 317 | |
| 318 | /* Answer whether the address part of SA is between A and B (inclusive). We |
| 319 | * assume that SA has the correct address family. |
| 320 | */ |
| 321 | static int sockaddr_in_range_p(const struct sockaddr *sa, |
| 322 | const ipaddr *a, const ipaddr *b) |
| 323 | { |
| 324 | switch (sa->sa_family) { |
| 325 | case AF_INET: { |
| 326 | unsigned long addr = ntohl(SIN(sa)->sin_addr.s_addr); |
| 327 | return (ntohl(a->v4.s_addr) <= addr && |
| 328 | addr <= ntohl(b->v4.s_addr)); |
| 329 | } break; |
| 330 | case AF_INET6: { |
| 331 | const uint8_t *ss = SIN6(sa)->sin6_addr.s6_addr; |
| 332 | const uint8_t *aa = a->v6.s6_addr, *bb = b->v6.s6_addr; |
| 333 | int h = 1, l = 1; |
| 334 | int i; |
| 335 | |
| 336 | for (i = 0; h && l && i < 16; i++, ss++, aa++, bb++) { |
| 337 | if (*ss < *aa || *bb < *ss) return (0); |
| 338 | if (*aa < *ss) l = 0; |
| 339 | if (*ss < *bb) h = 0; |
| 340 | } |
| 341 | return (1); |
| 342 | } break; |
| 343 | default: |
| 344 | abort(); |
| 345 | } |
| 346 | } |
| 347 | |
| 348 | /* Fill in SA with the appropriate wildcard address. */ |
| 349 | static void wildcard_address(int af, struct sockaddr *sa) |
| 350 | { |
| 351 | switch (af) { |
| 352 | case AF_INET: { |
| 353 | struct sockaddr_in *sin = SIN(sa); |
| 354 | memset(sin, 0, sizeof(*sin)); |
| 355 | sin->sin_family = AF_INET; |
| 356 | sin->sin_port = 0; |
| 357 | sin->sin_addr.s_addr = INADDR_ANY; |
| 358 | } break; |
| 359 | case AF_INET6: { |
| 360 | struct sockaddr_in6 *sin6 = SIN6(sa); |
| 361 | memset(sin6, 0, sizeof(*sin6)); |
| 362 | sin6->sin6_family = AF_INET6; |
| 363 | sin6->sin6_port = 0; |
| 364 | sin6->sin6_addr = in6addr_any; |
| 365 | sin6->sin6_scope_id = 0; |
| 366 | sin6->sin6_flowinfo = 0; |
| 367 | } break; |
| 368 | default: |
| 369 | abort(); |
| 370 | } |
| 371 | } |
| 372 | |
| 373 | /* Mask the address A, forcing all but the top PLEN bits to zero or one |
| 374 | * according to HIGHP. |
| 375 | */ |
| 376 | static void mask_address(int af, ipaddr *a, int plen, int highp) |
| 377 | { |
| 378 | switch (af) { |
| 379 | case AF_INET: { |
| 380 | unsigned long addr = ntohl(a->v4.s_addr); |
| 381 | unsigned long mask = plen ? ~0ul << (32 - plen) : 0; |
| 382 | addr &= mask; |
| 383 | if (highp) addr |= ~mask; |
| 384 | a->v4.s_addr = htonl(addr & 0xffffffff); |
| 385 | } break; |
| 386 | case AF_INET6: { |
| 387 | int i = plen/8; |
| 388 | unsigned m = (0xff << (8 - plen%8)) & 0xff; |
| 389 | unsigned s = highp ? 0xff : 0; |
| 390 | if (m) { |
| 391 | a->v6.s6_addr[i] = (a->v6.s6_addr[i] & m) | (s & ~m); |
| 392 | i++; |
| 393 | } |
| 394 | for (; i < 16; i++) a->v6.s6_addr[i] = s; |
| 395 | } break; |
| 396 | default: |
| 397 | abort(); |
| 398 | } |
| 399 | } |
| 400 | |
| 401 | /* Write a presentation form of SA to BUF, a buffer of length SZ. LEN is the |
| 402 | * address length; if it's zero, look it up based on the address family. |
| 403 | * Return a pointer to the string (which might, in an emergency, be a static |
| 404 | * string rather than your buffer). |
| 405 | */ |
| 406 | static char *present_sockaddr(const struct sockaddr *sa, socklen_t len, |
| 407 | char *buf, size_t sz) |
| 408 | { |
| 409 | #define WANT(n_) do { if (sz < (n_)) goto nospace; } while (0) |
| 410 | #define PUTC(c_) do { *buf++ = (c_); sz--; } while (0) |
| 411 | |
| 412 | if (!sa) return "<null-address>"; |
| 413 | if (!sz) return "<no-space-in-buffer>"; |
| 414 | if (!len) len = family_socklen(sa->sa_family); |
| 415 | |
| 416 | switch (sa->sa_family) { |
| 417 | case AF_UNIX: { |
| 418 | struct sockaddr_un *sun = SUN(sa); |
| 419 | char *p = sun->sun_path; |
| 420 | size_t n = len - offsetof(struct sockaddr_un, sun_path); |
| 421 | |
| 422 | assert(n); |
| 423 | if (*p == 0) { |
| 424 | WANT(1); PUTC('@'); |
| 425 | p++; n--; |
| 426 | while (n) { |
| 427 | switch (*p) { |
| 428 | case 0: WANT(2); PUTC('\\'); PUTC('0'); break; |
| 429 | case '\a': WANT(2); PUTC('\\'); PUTC('a'); break; |
| 430 | case '\n': WANT(2); PUTC('\\'); PUTC('n'); break; |
| 431 | case '\r': WANT(2); PUTC('\\'); PUTC('r'); break; |
| 432 | case '\t': WANT(2); PUTC('\\'); PUTC('t'); break; |
| 433 | case '\v': WANT(2); PUTC('\\'); PUTC('v'); break; |
| 434 | case '\\': WANT(2); PUTC('\\'); PUTC('\\'); break; |
| 435 | default: |
| 436 | if (*p > ' ' && *p <= '~') |
| 437 | { WANT(1); PUTC(*p); } |
| 438 | else { |
| 439 | WANT(4); PUTC('\\'); PUTC('x'); |
| 440 | PUTC((*p >> 4)&0xf); PUTC((*p >> 0)&0xf); |
| 441 | } |
| 442 | break; |
| 443 | } |
| 444 | p++; n--; |
| 445 | } |
| 446 | } else { |
| 447 | if (*p != '/') { WANT(2); PUTC('.'); PUTC('/'); } |
| 448 | while (n && *p) { WANT(1); PUTC(*p); p++; n--; } |
| 449 | } |
| 450 | WANT(1); PUTC(0); |
| 451 | } break; |
| 452 | case AF_INET: case AF_INET6: { |
| 453 | char addrbuf[NI_MAXHOST], portbuf[NI_MAXSERV]; |
| 454 | int err = getnameinfo(sa, len, |
| 455 | addrbuf, sizeof(addrbuf), |
| 456 | portbuf, sizeof(portbuf), |
| 457 | NI_NUMERICHOST | NI_NUMERICSERV); |
| 458 | assert(!err); |
| 459 | snprintf(buf, sz, strchr(addrbuf, ':') ? "[%s]:%s" : "%s:%s", |
| 460 | addrbuf, portbuf); |
| 461 | } break; |
| 462 | default: |
| 463 | snprintf(buf, sz, "<unknown-address-family %d>", sa->sa_family); |
| 464 | break; |
| 465 | } |
| 466 | return (buf); |
| 467 | |
| 468 | nospace: |
| 469 | buf[sz - 1] = 0; |
| 470 | return (buf); |
| 471 | } |
| 472 | |
| 473 | /* Guess the family of a textual socket address. */ |
| 474 | static int guess_address_family(const char *p) |
| 475 | { return (strchr(p, ':') ? AF_INET6 : AF_INET); } |
| 476 | |
| 477 | /* Parse a socket address P and write the result to SA. */ |
| 478 | static int parse_sockaddr(struct sockaddr *sa, const char *p) |
| 479 | { |
| 480 | char buf[ADDRBUFSZ]; |
| 481 | char *q; |
| 482 | struct addrinfo *ai, ai_hint = { 0 }; |
| 483 | |
| 484 | if (strlen(p) >= sizeof(buf) - 1) return (-1); |
| 485 | strcpy(buf, p); p = buf; |
| 486 | if (*p != '[') { |
| 487 | if ((q = strchr(p, ':')) == 0) return (-1); |
| 488 | *q++ = 0; |
| 489 | } else { |
| 490 | p++; |
| 491 | if ((q = strchr(p, ']')) == 0) return (-1); |
| 492 | *q++ = 0; |
| 493 | if (*q != ':') return (-1); |
| 494 | q++; |
| 495 | } |
| 496 | |
| 497 | ai_hint.ai_family = AF_UNSPEC; |
| 498 | ai_hint.ai_socktype = SOCK_DGRAM; |
| 499 | ai_hint.ai_flags = AI_NUMERICHOST | AI_NUMERICSERV; |
| 500 | if (getaddrinfo(p, q, &ai_hint, &ai)) return (-1); |
| 501 | memcpy(sa, ai->ai_addr, ai->ai_addrlen); |
| 502 | freeaddrinfo(ai); |
| 503 | return (0); |
| 504 | } |
| 505 | |
| 506 | /*----- Access control lists ----------------------------------------------*/ |
| 507 | |
| 508 | #ifdef DEBUG |
| 509 | |
| 510 | /* Write to standard error a description of the ACL node A. */ |
| 511 | static void dump_aclnode(const aclnode *a) |
| 512 | { |
| 513 | char buf[ADDRBUFSZ]; |
| 514 | const char *p; |
| 515 | int plen; |
| 516 | |
| 517 | fprintf(stderr, "noip(%d): %c ", getpid(), a->act ? '+' : '-'); |
| 518 | plen = common_prefix_length(a->af, &a->minaddr, &a->maxaddr); |
| 519 | p = inet_ntop(a->af, &a->minaddr, buf, sizeof(buf)); |
| 520 | fprintf(stderr, strchr(p, ':') ? "[%s]" : "%s", p); |
| 521 | if (plen < 0) { |
| 522 | p = inet_ntop(a->af, &a->maxaddr, buf, sizeof(buf)); |
| 523 | fprintf(stderr, strchr(p, ':') ? "-[%s]" : "-%s", p); |
| 524 | } else if (plen < address_width(a->af)) |
| 525 | fprintf(stderr, "/%d", plen); |
| 526 | if (a->minport != 0 || a->maxport != 0xffff) { |
| 527 | fprintf(stderr, ":%u", (unsigned)a->minport); |
| 528 | if (a->minport != a->maxport) |
| 529 | fprintf(stderr, "-%u", (unsigned)a->maxport); |
| 530 | } |
| 531 | fputc('\n', stderr); |
| 532 | } |
| 533 | |
| 534 | static void dump_acl(const aclnode *a) |
| 535 | { |
| 536 | int act = ALLOW; |
| 537 | |
| 538 | for (; a; a = a->next) { |
| 539 | dump_aclnode(a); |
| 540 | act = a->act; |
| 541 | } |
| 542 | fprintf(stderr, "noip(%d): [default policy: %s]\n", getpid(), |
| 543 | act == ALLOW ? "DENY" : "ALLOW"); |
| 544 | } |
| 545 | |
| 546 | #endif |
| 547 | |
| 548 | /* Returns nonzero if the ACL A allows the socket address SA. */ |
| 549 | static int acl_allows_p(const aclnode *a, const struct sockaddr *sa) |
| 550 | { |
| 551 | unsigned short port = port_from_sockaddr(sa); |
| 552 | int act = ALLOW; |
| 553 | Dpid; |
| 554 | |
| 555 | D({ char buf[ADDRBUFSZ]; |
| 556 | fprintf(stderr, "noip(%d): check %s\n", pid, |
| 557 | present_sockaddr(sa, 0, buf, sizeof(buf))); }) |
| 558 | for (; a; a = a->next) { |
| 559 | D( dump_aclnode(a); ) |
| 560 | if (sockaddr_in_range_p(sa, &a->minaddr, &a->maxaddr) && |
| 561 | a->minport <= port && port <= a->maxport) { |
| 562 | D( fprintf(stderr, "noip(%d): aha! %s\n", pid, |
| 563 | a->act ? "ALLOW" : "DENY"); ) |
| 564 | return (a->act); |
| 565 | } |
| 566 | act = a->act; |
| 567 | } |
| 568 | D( fprintf(stderr, "noip(%d): nothing found: %s\n", pid, |
| 569 | act ? "DENY" : "ALLOW"); ) |
| 570 | return (!act); |
| 571 | } |
| 572 | |
| 573 | /*----- Socket address conversion -----------------------------------------*/ |
| 574 | |
| 575 | /* Return a uniformly distributed integer between MIN and MAX inclusive. */ |
| 576 | static unsigned randrange(unsigned min, unsigned max) |
| 577 | { |
| 578 | unsigned mask, i; |
| 579 | |
| 580 | /* It's so nice not to have to care about the quality of the generator |
| 581 | * much! |
| 582 | */ |
| 583 | max -= min; |
| 584 | for (mask = 1; mask < max; mask = (mask << 1) | 1) |
| 585 | ; |
| 586 | do i = rand() & mask; while (i > max); |
| 587 | return (i + min); |
| 588 | } |
| 589 | |
| 590 | /* Return the status of Unix-domain socket address SUN. Returns: UNUSED if |
| 591 | * the socket doesn't exist; USED if the path refers to an active socket, or |
| 592 | * isn't really a socket at all, or we can't tell without a careful search |
| 593 | * and QUICKP is set; or STALE if the file refers to a socket which isn't |
| 594 | * being used any more. |
| 595 | */ |
| 596 | static int unix_socket_status(struct sockaddr_un *sun, int quickp) |
| 597 | { |
| 598 | struct stat st; |
| 599 | FILE *fp = 0; |
| 600 | size_t len, n; |
| 601 | int rc; |
| 602 | char buf[256]; |
| 603 | |
| 604 | if (stat(sun->sun_path, &st)) |
| 605 | return (errno == ENOENT ? UNUSED : USED); |
| 606 | if (!S_ISSOCK(st.st_mode) || quickp) |
| 607 | return (USED); |
| 608 | rc = USED; |
| 609 | if ((fp = fopen("/proc/net/unix", "r")) == 0) |
| 610 | goto done; |
| 611 | if (!fgets(buf, sizeof(buf), fp)) goto done; /* skip header */ |
| 612 | len = strlen(sun->sun_path); |
| 613 | while (fgets(buf, sizeof(buf), fp)) { |
| 614 | n = strlen(buf); |
| 615 | if (n >= len + 2 && buf[n - len - 2] == ' ' && buf[n - 1] == '\n' && |
| 616 | memcmp(buf + n - len - 1, sun->sun_path, len) == 0) |
| 617 | goto done; |
| 618 | } |
| 619 | if (ferror(fp)) |
| 620 | goto done; |
| 621 | rc = STALE; |
| 622 | done: |
| 623 | if (fp) fclose(fp); |
| 624 | return (rc); |
| 625 | } |
| 626 | |
| 627 | /* Encode the Internet address SA as a Unix-domain address SUN. If WANT is |
| 628 | * WANT_FRESH, and SA's port number is zero, then we pick an arbitrary local |
| 629 | * port. Otherwise we pick the port given. There's an unpleasant hack to |
| 630 | * find servers bound to local wildcard addresses. Returns zero on success; |
| 631 | * -1 on failure. |
| 632 | */ |
| 633 | static int encode_inet_addr(struct sockaddr_un *sun, |
| 634 | const struct sockaddr *sa, |
| 635 | int want) |
| 636 | { |
| 637 | int i; |
| 638 | int desperatep = 0; |
| 639 | address addr; |
| 640 | char buf[ADDRBUFSZ]; |
| 641 | int rc; |
| 642 | |
| 643 | D( fprintf(stderr, "noip(%d): encode %s (%s)", getpid(), |
| 644 | present_sockaddr(sa, 0, buf, sizeof(buf)), |
| 645 | want == WANT_EXISTING ? "EXISTING" : "FRESH"); ) |
| 646 | sun->sun_family = AF_UNIX; |
| 647 | if (port_from_sockaddr(sa) || want == WANT_EXISTING) { |
| 648 | snprintf(sun->sun_path, sizeof(sun->sun_path), "%s/%s", sockdir, |
| 649 | present_sockaddr(sa, 0, buf, sizeof(buf))); |
| 650 | rc = unix_socket_status(sun, 0); |
| 651 | if (rc == STALE) unlink(sun->sun_path); |
| 652 | if (rc != USED && want == WANT_EXISTING) { |
| 653 | wildcard_address(sa->sa_family, &addr.sa); |
| 654 | port_to_sockaddr(&addr.sa, port_from_sockaddr(sa)); |
| 655 | snprintf(sun->sun_path, sizeof(sun->sun_path), "%s/%s", sockdir, |
| 656 | present_sockaddr(&addr.sa, 0, buf, sizeof(buf))); |
| 657 | if (unix_socket_status(sun, 0) == STALE) unlink(sun->sun_path); |
| 658 | } |
| 659 | } else { |
| 660 | copy_sockaddr(&addr.sa, sa); |
| 661 | for (i = 0; i < 10; i++) { |
| 662 | port_to_sockaddr(&addr.sa, randrange(minautoport, maxautoport)); |
| 663 | snprintf(sun->sun_path, sizeof(sun->sun_path), "%s/%s", sockdir, |
| 664 | present_sockaddr(&addr.sa, 0, buf, sizeof(buf))); |
| 665 | if (unix_socket_status(sun, 1) == UNUSED) goto found; |
| 666 | } |
| 667 | for (desperatep = 0; desperatep < 2; desperatep++) { |
| 668 | for (i = minautoport; i <= maxautoport; i++) { |
| 669 | port_to_sockaddr(&addr.sa, i); |
| 670 | snprintf(sun->sun_path, sizeof(sun->sun_path), "%s/%s", sockdir, |
| 671 | present_sockaddr(&addr.sa, 0, buf, sizeof(buf))); |
| 672 | rc = unix_socket_status(sun, !desperatep); |
| 673 | switch (rc) { |
| 674 | case STALE: unlink(sun->sun_path); |
| 675 | case UNUSED: goto found; |
| 676 | } |
| 677 | } |
| 678 | } |
| 679 | errno = EADDRINUSE; |
| 680 | D( fprintf(stderr, " -- can't resolve\n"); ) |
| 681 | return (-1); |
| 682 | found:; |
| 683 | } |
| 684 | D( fprintf(stderr, " -> `%s'\n", sun->sun_path); ) |
| 685 | return (0); |
| 686 | } |
| 687 | |
| 688 | /* Decode the Unix address SUN to an Internet address SIN. If AF_HINT is |
| 689 | * nonzero, an empty address (indicative of an unbound Unix-domain socket) is |
| 690 | * translated to a wildcard Internet address of the appropriate family. |
| 691 | * Returns zero on success; -1 on failure (e.g., it wasn't one of our |
| 692 | * addresses). |
| 693 | */ |
| 694 | static int decode_inet_addr(struct sockaddr *sa, int af_hint, |
| 695 | const struct sockaddr_un *sun, |
| 696 | socklen_t len) |
| 697 | { |
| 698 | char buf[ADDRBUFSZ]; |
| 699 | size_t n = strlen(sockdir), nn; |
| 700 | address addr; |
| 701 | |
| 702 | if (!sa) sa = &addr.sa; |
| 703 | if (sun->sun_family != AF_UNIX) return (-1); |
| 704 | if (len > sizeof(*sun)) return (-1); |
| 705 | ((char *)sun)[len] = 0; |
| 706 | nn = strlen(sun->sun_path); |
| 707 | D( fprintf(stderr, "noip(%d): decode `%s'", getpid(), sun->sun_path); ) |
| 708 | if (af_hint && !sun->sun_path[0]) { |
| 709 | wildcard_address(af_hint, sa); |
| 710 | D( fprintf(stderr, " -- unbound socket\n"); ) |
| 711 | return (0); |
| 712 | } |
| 713 | if (nn < n + 1 || nn - n >= sizeof(buf) || sun->sun_path[n] != '/' || |
| 714 | memcmp(sun->sun_path, sockdir, n) != 0) { |
| 715 | D( fprintf(stderr, " -- not one of ours\n"); ) |
| 716 | return (-1); |
| 717 | } |
| 718 | if (parse_sockaddr(sa, sun->sun_path + n + 1)) return (-1); |
| 719 | D( fprintf(stderr, " -> %s\n", |
| 720 | present_sockaddr(sa, 0, buf, sizeof(buf))); ) |
| 721 | return (0); |
| 722 | } |
| 723 | |
| 724 | /* SK is (or at least might be) a Unix-domain socket we created when an |
| 725 | * Internet socket was asked for. We've decided it should be an Internet |
| 726 | * socket after all, with family AF_HINT, so convert it. If TMP is not null, |
| 727 | * then don't replace the existing descriptor: store the new socket in *TMP |
| 728 | * and return zero. |
| 729 | */ |
| 730 | static int fixup_real_ip_socket(int sk, int af_hint, int *tmp) |
| 731 | { |
| 732 | int nsk; |
| 733 | int type; |
| 734 | int f, fd; |
| 735 | struct sockaddr_un sun; |
| 736 | address addr; |
| 737 | socklen_t len; |
| 738 | |
| 739 | #define OPTS(_) \ |
| 740 | _(DEBUG, int) \ |
| 741 | _(REUSEADDR, int) \ |
| 742 | _(DONTROUTE, int) \ |
| 743 | _(BROADCAST, int) \ |
| 744 | _(SNDBUF, int) \ |
| 745 | _(RCVBUF, int) \ |
| 746 | _(OOBINLINE, int) \ |
| 747 | _(NO_CHECK, int) \ |
| 748 | _(LINGER, struct linger) \ |
| 749 | _(BSDCOMPAT, int) \ |
| 750 | _(RCVLOWAT, int) \ |
| 751 | _(RCVTIMEO, struct timeval) \ |
| 752 | _(SNDTIMEO, struct timeval) |
| 753 | |
| 754 | len = sizeof(sun); |
| 755 | if (real_getsockname(sk, SA(&sun), &len)) |
| 756 | return (-1); |
| 757 | if (decode_inet_addr(&addr.sa, af_hint, &sun, len)) |
| 758 | return (0); /* Not one of ours */ |
| 759 | len = sizeof(type); |
| 760 | if (real_getsockopt(sk, SOL_SOCKET, SO_TYPE, &type, &len) < 0 || |
| 761 | (nsk = real_socket(addr.sa.sa_family, type, 0)) < 0) |
| 762 | return (-1); |
| 763 | #define FIX(opt, ty) do { \ |
| 764 | ty ov_; \ |
| 765 | len = sizeof(ov_); \ |
| 766 | if (real_getsockopt(sk, SOL_SOCKET, SO_##opt, &ov_, &len) < 0 || \ |
| 767 | real_setsockopt(nsk, SOL_SOCKET, SO_##opt, &ov_, len)) { \ |
| 768 | close(nsk); \ |
| 769 | return (-1); \ |
| 770 | } \ |
| 771 | } while (0); |
| 772 | OPTS(FIX) |
| 773 | #undef FIX |
| 774 | if (tmp) |
| 775 | *tmp = nsk; |
| 776 | else { |
| 777 | if ((f = fcntl(sk, F_GETFL)) < 0 || |
| 778 | (fd = fcntl(sk, F_GETFD)) < 0 || |
| 779 | fcntl(nsk, F_SETFL, f) < 0 || |
| 780 | dup2(nsk, sk) < 0) { |
| 781 | close(nsk); |
| 782 | return (-1); |
| 783 | } |
| 784 | unlink(sun.sun_path); |
| 785 | close(nsk); |
| 786 | if (fcntl(sk, F_SETFD, fd) < 0) { |
| 787 | perror("noip: fixup_real_ip_socket F_SETFD"); |
| 788 | abort(); |
| 789 | } |
| 790 | } |
| 791 | return (0); |
| 792 | } |
| 793 | |
| 794 | /* The socket SK is about to be used to communicate with the remote address |
| 795 | * SA. Assign it a local address so that getpeername(2) does something |
| 796 | * useful. |
| 797 | */ |
| 798 | static int do_implicit_bind(int sk, const struct sockaddr **sa, |
| 799 | socklen_t *len, struct sockaddr_un *sun) |
| 800 | { |
| 801 | address addr; |
| 802 | socklen_t mylen = sizeof(*sun); |
| 803 | |
| 804 | if (acl_allows_p(connect_real, *sa)) { |
| 805 | if (fixup_real_ip_socket(sk, (*sa)->sa_family, 0)) return (-1); |
| 806 | } else { |
| 807 | if (real_getsockname(sk, SA(sun), &mylen) < 0) return (-1); |
| 808 | if (sun->sun_family == AF_UNIX) { |
| 809 | if (mylen < sizeof(*sun)) ((char *)sun)[mylen] = 0; |
| 810 | if (!sun->sun_path[0]) { |
| 811 | wildcard_address((*sa)->sa_family, &addr.sa); |
| 812 | encode_inet_addr(sun, &addr.sa, WANT_FRESH); |
| 813 | if (real_bind(sk, SA(sun), SUN_LEN(sun))) return (-1); |
| 814 | } |
| 815 | encode_inet_addr(sun, *sa, WANT_EXISTING); |
| 816 | *sa = SA(sun); |
| 817 | *len = SUN_LEN(sun); |
| 818 | } |
| 819 | } |
| 820 | return (0); |
| 821 | } |
| 822 | |
| 823 | /* We found the real address SA, with length LEN; if it's a Unix-domain |
| 824 | * address corresponding to a fake socket, convert it to cover up the |
| 825 | * deception. Whatever happens, put the result at FAKE and store its length |
| 826 | * at FAKELEN. |
| 827 | */ |
| 828 | static void return_fake_name(struct sockaddr *sa, socklen_t len, |
| 829 | struct sockaddr *fake, socklen_t *fakelen) |
| 830 | { |
| 831 | address addr; |
| 832 | socklen_t alen; |
| 833 | |
| 834 | if (sa->sa_family == AF_UNIX && |
| 835 | !decode_inet_addr(&addr.sa, 0, SUN(sa), len)) { |
| 836 | sa = &addr.sa; |
| 837 | len = family_socklen(addr.sa.sa_family); |
| 838 | } |
| 839 | alen = len; |
| 840 | if (len > *fakelen) len = *fakelen; |
| 841 | if (len > 0) memcpy(fake, sa, len); |
| 842 | *fakelen = alen; |
| 843 | } |
| 844 | |
| 845 | /*----- Configuration -----------------------------------------------------*/ |
| 846 | |
| 847 | /* Return the process owner's home directory. */ |
| 848 | static char *home(void) |
| 849 | { |
| 850 | char *p; |
| 851 | struct passwd *pw; |
| 852 | |
| 853 | if (getuid() == uid && |
| 854 | (p = getenv("HOME")) != 0) |
| 855 | return (p); |
| 856 | else if ((pw = getpwuid(uid)) != 0) |
| 857 | return (pw->pw_dir); |
| 858 | else |
| 859 | return "/notexist"; |
| 860 | } |
| 861 | |
| 862 | /* Return a good temporary directory to use. */ |
| 863 | static char *tmpdir(void) |
| 864 | { |
| 865 | char *p; |
| 866 | |
| 867 | if ((p = getenv("TMPDIR")) != 0) return (p); |
| 868 | else if ((p = getenv("TMP")) != 0) return (p); |
| 869 | else return ("/tmp"); |
| 870 | } |
| 871 | |
| 872 | /* Return the user's name, or at least something distinctive. */ |
| 873 | static char *user(void) |
| 874 | { |
| 875 | static char buf[16]; |
| 876 | char *p; |
| 877 | struct passwd *pw; |
| 878 | |
| 879 | if ((p = getenv("USER")) != 0) return (p); |
| 880 | else if ((p = getenv("LOGNAME")) != 0) return (p); |
| 881 | else if ((pw = getpwuid(uid)) != 0) return (pw->pw_name); |
| 882 | else { |
| 883 | snprintf(buf, sizeof(buf), "uid-%lu", (unsigned long)uid); |
| 884 | return (buf); |
| 885 | } |
| 886 | } |
| 887 | |
| 888 | /* Skip P over space characters. */ |
| 889 | #define SKIPSPC do { while (*p && isspace(UC(*p))) p++; } while (0) |
| 890 | |
| 891 | /* Set Q to point to the next word following P, null-terminate it, and step P |
| 892 | * past it. */ |
| 893 | #define NEXTWORD(q) do { \ |
| 894 | SKIPSPC; \ |
| 895 | q = p; \ |
| 896 | while (*p && !isspace(UC(*p))) p++; \ |
| 897 | if (*p) *p++ = 0; \ |
| 898 | } while (0) |
| 899 | |
| 900 | /* Set Q to point to the next dotted-quad address, store the ending delimiter |
| 901 | * in DEL, null-terminate it, and step P past it. */ |
| 902 | static void parse_nextaddr(char **pp, char **qq, int *del) |
| 903 | { |
| 904 | char *p = *pp; |
| 905 | |
| 906 | SKIPSPC; |
| 907 | if (*p == '[') { |
| 908 | p++; SKIPSPC; |
| 909 | *qq = p; |
| 910 | p += strcspn(p, "]"); |
| 911 | if (*p) *p++ = 0; |
| 912 | *del = 0; |
| 913 | } else { |
| 914 | *qq = p; |
| 915 | while (*p && (*p == '.' || isdigit(UC(*p)))) p++; |
| 916 | *del = *p; |
| 917 | if (*p) *p++ = 0; |
| 918 | } |
| 919 | *pp = p; |
| 920 | } |
| 921 | |
| 922 | /* Set Q to point to the next decimal number, store the ending delimiter in |
| 923 | * DEL, null-terminate it, and step P past it. */ |
| 924 | #define NEXTNUMBER(q, del) do { \ |
| 925 | SKIPSPC; \ |
| 926 | q = p; \ |
| 927 | while (*p && isdigit(UC(*p))) p++; \ |
| 928 | del = *p; \ |
| 929 | if (*p) *p++ = 0; \ |
| 930 | } while (0) |
| 931 | |
| 932 | /* Push the character DEL back so we scan it again, unless it's zero |
| 933 | * (end-of-file). */ |
| 934 | #define RESCAN(del) do { if (del) *--p = del; } while (0) |
| 935 | |
| 936 | /* Evaluate true if P is pointing to the word KW (and not some longer string |
| 937 | * of which KW is a prefix). */ |
| 938 | |
| 939 | #define KWMATCHP(kw) (strncmp(p, kw, sizeof(kw) - 1) == 0 && \ |
| 940 | !isalnum(UC(p[sizeof(kw) - 1])) && \ |
| 941 | (p += sizeof(kw) - 1)) |
| 942 | |
| 943 | /* Parse a port list, starting at *PP. Port lists have the form |
| 944 | * [:LOW[-HIGH]]: if omitted, all ports are included; if HIGH is omitted, |
| 945 | * it's as if HIGH = LOW. Store LOW in *MIN, HIGH in *MAX and set *PP to the |
| 946 | * rest of the string. |
| 947 | */ |
| 948 | static void parse_ports(char **pp, unsigned short *min, unsigned short *max) |
| 949 | { |
| 950 | char *p = *pp, *q; |
| 951 | int del; |
| 952 | |
| 953 | SKIPSPC; |
| 954 | if (*p != ':') |
| 955 | { *min = 0; *max = 0xffff; } |
| 956 | else { |
| 957 | p++; |
| 958 | NEXTNUMBER(q, del); *min = strtoul(q, 0, 0); RESCAN(del); |
| 959 | SKIPSPC; |
| 960 | if (*p == '-') |
| 961 | { p++; NEXTNUMBER(q, del); *max = strtoul(q, 0, 0); RESCAN(del); } |
| 962 | else |
| 963 | *max = *min; |
| 964 | } |
| 965 | *pp = p; |
| 966 | } |
| 967 | |
| 968 | /* Make a new ACL node. ACT is the verdict; AF is the address family; |
| 969 | * MINADDR and MAXADDR are the ranges on IP addresses; MINPORT and MAXPORT |
| 970 | * are the ranges on port numbers; TAIL is the list tail to attach the new |
| 971 | * node to. |
| 972 | */ |
| 973 | #define ACLNODE(tail_, act_, \ |
| 974 | af_, minaddr_, maxaddr_, minport_, maxport_) do { \ |
| 975 | aclnode *a_; \ |
| 976 | NEW(a_); \ |
| 977 | a_->act = (act_); \ |
| 978 | a_->af = (af_); \ |
| 979 | a_->minaddr = (minaddr_); a_->maxaddr = (maxaddr_); \ |
| 980 | a_->minport = (minport_); a_->maxport = (maxport_); \ |
| 981 | *tail_ = a_; tail_ = &a_->next; \ |
| 982 | } while (0) |
| 983 | |
| 984 | /* Parse an ACL line. *PP points to the end of the line; *TAIL points to |
| 985 | * the list tail (i.e., the final link in the list). An ACL entry has the |
| 986 | * form +|- [any | local | ADDR | ADDR - ADDR | ADDR/ADDR | ADDR/INT] PORTS |
| 987 | * where PORTS is parsed by parse_ports above; an ACL line consists of a |
| 988 | * comma-separated sequence of entries.. |
| 989 | */ |
| 990 | static void parse_acl_line(char **pp, aclnode ***tail) |
| 991 | { |
| 992 | ipaddr minaddr, maxaddr; |
| 993 | unsigned short minport, maxport; |
| 994 | int i, af, n; |
| 995 | int act; |
| 996 | int del; |
| 997 | char *p = *pp; |
| 998 | char *q; |
| 999 | |
| 1000 | for (;;) { |
| 1001 | SKIPSPC; |
| 1002 | if (*p == '+') act = ALLOW; |
| 1003 | else if (*p == '-') act = DENY; |
| 1004 | else goto bad; |
| 1005 | |
| 1006 | p++; |
| 1007 | SKIPSPC; |
| 1008 | if (KWMATCHP("any")) { |
| 1009 | parse_ports(&p, &minport, &maxport); |
| 1010 | for (i = 0; address_families[i] >= 0; i++) { |
| 1011 | af = address_families[i]; |
| 1012 | memset(&minaddr, 0, sizeof(minaddr)); |
| 1013 | maxaddr = minaddr; mask_address(af, &maxaddr, 0, 1); |
| 1014 | ACLNODE(*tail, act, af, minaddr, maxaddr, minport, maxport); |
| 1015 | } |
| 1016 | } else if (KWMATCHP("local")) { |
| 1017 | parse_ports(&p, &minport, &maxport); |
| 1018 | for (i = 0; address_families[i] >= 0; i++) { |
| 1019 | af = address_families[i]; |
| 1020 | memset(&minaddr, 0, sizeof(minaddr)); |
| 1021 | maxaddr = minaddr; mask_address(af, &maxaddr, 0, 1); |
| 1022 | ACLNODE(*tail, act, af, minaddr, minaddr, minport, maxport); |
| 1023 | ACLNODE(*tail, act, af, maxaddr, maxaddr, minport, maxport); |
| 1024 | } |
| 1025 | for (i = 0; i < n_local_ipaddrs; i++) { |
| 1026 | ACLNODE(*tail, act, local_ipaddrs[i].af, |
| 1027 | local_ipaddrs[i].addr, local_ipaddrs[i].addr, |
| 1028 | minport, maxport); |
| 1029 | } |
| 1030 | } else { |
| 1031 | parse_nextaddr(&p, &q, &del); |
| 1032 | af = guess_address_family(q); |
| 1033 | if (inet_pton(af, q, &minaddr) <= 0) goto bad; |
| 1034 | RESCAN(del); |
| 1035 | SKIPSPC; |
| 1036 | if (*p == '-') { |
| 1037 | p++; |
| 1038 | parse_nextaddr(&p, &q, &del); |
| 1039 | if (inet_pton(af, q, &maxaddr) <= 0) goto bad; |
| 1040 | RESCAN(del); |
| 1041 | } else if (*p == '/') { |
| 1042 | p++; |
| 1043 | NEXTNUMBER(q, del); |
| 1044 | n = strtoul(q, 0, 0); |
| 1045 | maxaddr = minaddr; |
| 1046 | mask_address(af, &minaddr, n, 0); |
| 1047 | mask_address(af, &maxaddr, n, 1); |
| 1048 | RESCAN(del); |
| 1049 | } else |
| 1050 | maxaddr = minaddr; |
| 1051 | parse_ports(&p, &minport, &maxport); |
| 1052 | ACLNODE(*tail, act, af, minaddr, maxaddr, minport, maxport); |
| 1053 | } |
| 1054 | SKIPSPC; |
| 1055 | if (*p != ',') break; |
| 1056 | if (*p) p++; |
| 1057 | } |
| 1058 | if (*p) goto bad; |
| 1059 | *pp = p; |
| 1060 | return; |
| 1061 | |
| 1062 | bad: |
| 1063 | D( fprintf(stderr, "noip(%d): bad acl spec (ignored)\n", getpid()); ) |
| 1064 | return; |
| 1065 | } |
| 1066 | |
| 1067 | /* Parse the autoports configuration directive. Syntax is MIN - MAX. */ |
| 1068 | static void parse_autoports(char **pp) |
| 1069 | { |
| 1070 | char *p = *pp, *q; |
| 1071 | unsigned x, y; |
| 1072 | int del; |
| 1073 | |
| 1074 | SKIPSPC; |
| 1075 | NEXTNUMBER(q, del); x = strtoul(q, 0, 0); RESCAN(del); |
| 1076 | SKIPSPC; |
| 1077 | if (*p != '-') goto bad; p++; |
| 1078 | NEXTNUMBER(q, del); y = strtoul(q, 0, 0); RESCAN(del); |
| 1079 | minautoport = x; maxautoport = y; |
| 1080 | SKIPSPC; if (*p) goto bad; |
| 1081 | *pp = p; |
| 1082 | return; |
| 1083 | |
| 1084 | bad: |
| 1085 | D( fprintf(stderr, "noip(%d): bad port range (ignored)\n", getpid()); ) |
| 1086 | return; |
| 1087 | } |
| 1088 | |
| 1089 | /* Parse an ACL from an environment variable VAR, attaching it to the list |
| 1090 | * TAIL. */ |
| 1091 | static void parse_acl_env(const char *var, aclnode ***tail) |
| 1092 | { |
| 1093 | char *p, *q; |
| 1094 | |
| 1095 | if ((p = getenv(var)) != 0) { |
| 1096 | p = q = xstrdup(p); |
| 1097 | parse_acl_line(&q, tail); |
| 1098 | free(p); |
| 1099 | } |
| 1100 | } |
| 1101 | |
| 1102 | /* Read the configuration from the config file and environment. */ |
| 1103 | static void readconfig(void) |
| 1104 | { |
| 1105 | FILE *fp; |
| 1106 | char buf[1024]; |
| 1107 | size_t n; |
| 1108 | char *p, *q, *cmd; |
| 1109 | Dpid; |
| 1110 | |
| 1111 | parse_acl_env("NOIP_REALBIND_BEFORE", &bind_tail); |
| 1112 | parse_acl_env("NOIP_REALCONNECT_BEFORE", &connect_tail); |
| 1113 | if ((p = getenv("NOIP_AUTOPORTS")) != 0) { |
| 1114 | p = q = xstrdup(p); |
| 1115 | parse_autoports(&q); |
| 1116 | free(p); |
| 1117 | } |
| 1118 | if ((p = getenv("NOIP_CONFIG")) == 0) |
| 1119 | snprintf(p = buf, sizeof(buf), "%s/.noip", home()); |
| 1120 | D( fprintf(stderr, "noip(%d): config file: %s\n", pid, p); ) |
| 1121 | |
| 1122 | if ((fp = fopen(p, "r")) == 0) { |
| 1123 | D( fprintf(stderr, "noip(%d): couldn't read config: %s\n", |
| 1124 | pid, strerror(errno)); ) |
| 1125 | goto done; |
| 1126 | } |
| 1127 | while (fgets(buf, sizeof(buf), fp)) { |
| 1128 | n = strlen(buf); |
| 1129 | p = buf; |
| 1130 | |
| 1131 | SKIPSPC; |
| 1132 | if (!*p || *p == '#') continue; |
| 1133 | while (n && isspace(UC(buf[n - 1]))) n--; |
| 1134 | buf[n] = 0; |
| 1135 | NEXTWORD(cmd); |
| 1136 | SKIPSPC; |
| 1137 | |
| 1138 | if (strcmp(cmd, "socketdir") == 0) |
| 1139 | sockdir = xstrdup(p); |
| 1140 | else if (strcmp(cmd, "realbind") == 0) |
| 1141 | parse_acl_line(&p, &bind_tail); |
| 1142 | else if (strcmp(cmd, "realconnect") == 0) |
| 1143 | parse_acl_line(&p, &connect_tail); |
| 1144 | else if (strcmp(cmd, "autoports") == 0) |
| 1145 | parse_autoports(&p); |
| 1146 | else if (strcmp(cmd, "debug") == 0) |
| 1147 | debug = *p ? atoi(p) : 1; |
| 1148 | else |
| 1149 | D( fprintf(stderr, "noip: bad config command %s\n", cmd); ) |
| 1150 | } |
| 1151 | fclose(fp); |
| 1152 | |
| 1153 | done: |
| 1154 | parse_acl_env("NOIP_REALBIND", &bind_tail); |
| 1155 | parse_acl_env("NOIP_REALCONNECT", &connect_tail); |
| 1156 | parse_acl_env("NOIP_REALBIND_AFTER", &bind_tail); |
| 1157 | parse_acl_env("NOIP_REALCONNECT_AFTER", &connect_tail); |
| 1158 | *bind_tail = 0; |
| 1159 | *connect_tail = 0; |
| 1160 | if (!sockdir) sockdir = getenv("NOIP_SOCKETDIR"); |
| 1161 | if (!sockdir) { |
| 1162 | snprintf(buf, sizeof(buf), "%s/noip-%s", tmpdir(), user()); |
| 1163 | sockdir = xstrdup(buf); |
| 1164 | } |
| 1165 | D( fprintf(stderr, "noip(%d): socketdir: %s\n", pid, sockdir); |
| 1166 | fprintf(stderr, "noip(%d): autoports: %u-%u\n", |
| 1167 | pid, minautoport, maxautoport); |
| 1168 | fprintf(stderr, "noip(%d): realbind acl:\n", pid); |
| 1169 | dump_acl(bind_real); |
| 1170 | fprintf(stderr, "noip(%d): realconnect acl:\n", pid); |
| 1171 | dump_acl(connect_real); ) |
| 1172 | } |
| 1173 | |
| 1174 | /*----- Overridden system calls -------------------------------------------*/ |
| 1175 | |
| 1176 | int socket(int pf, int ty, int proto) |
| 1177 | { |
| 1178 | switch (pf) { |
| 1179 | default: |
| 1180 | if (!family_known_p(pf)) { |
| 1181 | errno = EAFNOSUPPORT; |
| 1182 | return (-1); |
| 1183 | } |
| 1184 | pf = PF_UNIX; |
| 1185 | proto = 0; |
| 1186 | case PF_UNIX: |
| 1187 | #ifdef PF_NETLINK |
| 1188 | case PF_NETLINK: |
| 1189 | #endif |
| 1190 | return (real_socket(pf, ty, proto)); |
| 1191 | } |
| 1192 | } |
| 1193 | |
| 1194 | int socketpair(int pf, int ty, int proto, int *sk) |
| 1195 | { |
| 1196 | if (family_known_p(pf)) { |
| 1197 | pf = PF_UNIX; |
| 1198 | proto = 0; |
| 1199 | } |
| 1200 | return (real_socketpair(pf, ty, proto, sk)); |
| 1201 | } |
| 1202 | |
| 1203 | int bind(int sk, const struct sockaddr *sa, socklen_t len) |
| 1204 | { |
| 1205 | struct sockaddr_un sun; |
| 1206 | |
| 1207 | if (family_known_p(sa->sa_family)) { |
| 1208 | PRESERVING_ERRNO({ |
| 1209 | if (acl_allows_p(bind_real, sa)) { |
| 1210 | if (fixup_real_ip_socket(sk, sa->sa_family, 0)) |
| 1211 | return (-1); |
| 1212 | } else { |
| 1213 | encode_inet_addr(&sun, sa, WANT_FRESH); |
| 1214 | sa = SA(&sun); |
| 1215 | len = SUN_LEN(&sun); |
| 1216 | } |
| 1217 | }); |
| 1218 | } |
| 1219 | return (real_bind(sk, sa, len)); |
| 1220 | } |
| 1221 | |
| 1222 | int connect(int sk, const struct sockaddr *sa, socklen_t len) |
| 1223 | { |
| 1224 | struct sockaddr_un sun; |
| 1225 | int rc; |
| 1226 | |
| 1227 | if (!family_known_p(sa->sa_family)) |
| 1228 | rc = real_connect(sk, sa, len); |
| 1229 | else { |
| 1230 | PRESERVING_ERRNO({ |
| 1231 | do_implicit_bind(sk, &sa, &len, &sun); |
| 1232 | }); |
| 1233 | rc = real_connect(sk, sa, len); |
| 1234 | if (rc < 0) { |
| 1235 | switch (errno) { |
| 1236 | case ENOENT: errno = ECONNREFUSED; break; |
| 1237 | } |
| 1238 | } |
| 1239 | } |
| 1240 | return (rc); |
| 1241 | } |
| 1242 | |
| 1243 | ssize_t sendto(int sk, const void *buf, size_t len, int flags, |
| 1244 | const struct sockaddr *to, socklen_t tolen) |
| 1245 | { |
| 1246 | struct sockaddr_un sun; |
| 1247 | |
| 1248 | if (to && family_known_p(to->sa_family)) { |
| 1249 | PRESERVING_ERRNO({ |
| 1250 | do_implicit_bind(sk, &to, &tolen, &sun); |
| 1251 | }); |
| 1252 | } |
| 1253 | return (real_sendto(sk, buf, len, flags, to, tolen)); |
| 1254 | } |
| 1255 | |
| 1256 | ssize_t recvfrom(int sk, void *buf, size_t len, int flags, |
| 1257 | struct sockaddr *from, socklen_t *fromlen) |
| 1258 | { |
| 1259 | char sabuf[1024]; |
| 1260 | socklen_t mylen = sizeof(sabuf); |
| 1261 | ssize_t n; |
| 1262 | |
| 1263 | if (!from) |
| 1264 | return real_recvfrom(sk, buf, len, flags, 0, 0); |
| 1265 | PRESERVING_ERRNO({ |
| 1266 | n = real_recvfrom(sk, buf, len, flags, SA(sabuf), &mylen); |
| 1267 | if (n < 0) |
| 1268 | return (-1); |
| 1269 | return_fake_name(SA(sabuf), mylen, from, fromlen); |
| 1270 | }); |
| 1271 | return (n); |
| 1272 | } |
| 1273 | |
| 1274 | ssize_t sendmsg(int sk, const struct msghdr *msg, int flags) |
| 1275 | { |
| 1276 | struct sockaddr_un sun; |
| 1277 | const struct sockaddr *sa; |
| 1278 | struct msghdr mymsg; |
| 1279 | |
| 1280 | if (msg->msg_name && family_known_p(SA(msg->msg_name)->sa_family)) { |
| 1281 | PRESERVING_ERRNO({ |
| 1282 | sa = SA(msg->msg_name); |
| 1283 | mymsg = *msg; |
| 1284 | do_implicit_bind(sk, &sa, &mymsg.msg_namelen, &sun); |
| 1285 | mymsg.msg_name = SA(sa); |
| 1286 | msg = &mymsg; |
| 1287 | }); |
| 1288 | } |
| 1289 | return (real_sendmsg(sk, msg, flags)); |
| 1290 | } |
| 1291 | |
| 1292 | ssize_t recvmsg(int sk, struct msghdr *msg, int flags) |
| 1293 | { |
| 1294 | char sabuf[1024]; |
| 1295 | struct sockaddr *sa; |
| 1296 | socklen_t len; |
| 1297 | ssize_t n; |
| 1298 | |
| 1299 | if (!msg->msg_name) |
| 1300 | return (real_recvmsg(sk, msg, flags)); |
| 1301 | PRESERVING_ERRNO({ |
| 1302 | sa = SA(msg->msg_name); |
| 1303 | len = msg->msg_namelen; |
| 1304 | msg->msg_name = sabuf; |
| 1305 | msg->msg_namelen = sizeof(sabuf); |
| 1306 | n = real_recvmsg(sk, msg, flags); |
| 1307 | if (n < 0) |
| 1308 | return (-1); |
| 1309 | return_fake_name(SA(sabuf), msg->msg_namelen, sa, &len); |
| 1310 | msg->msg_name = sa; |
| 1311 | msg->msg_namelen = len; |
| 1312 | }); |
| 1313 | return (n); |
| 1314 | } |
| 1315 | |
| 1316 | int accept(int sk, struct sockaddr *sa, socklen_t *len) |
| 1317 | { |
| 1318 | char sabuf[1024]; |
| 1319 | socklen_t mylen = sizeof(sabuf); |
| 1320 | int nsk = real_accept(sk, SA(sabuf), &mylen); |
| 1321 | |
| 1322 | if (nsk < 0) |
| 1323 | return (-1); |
| 1324 | return_fake_name(SA(sabuf), mylen, sa, len); |
| 1325 | return (nsk); |
| 1326 | } |
| 1327 | |
| 1328 | int getsockname(int sk, struct sockaddr *sa, socklen_t *len) |
| 1329 | { |
| 1330 | PRESERVING_ERRNO({ |
| 1331 | char sabuf[1024]; |
| 1332 | socklen_t mylen = sizeof(sabuf); |
| 1333 | if (real_getsockname(sk, SA(sabuf), &mylen)) |
| 1334 | return (-1); |
| 1335 | return_fake_name(SA(sabuf), mylen, sa, len); |
| 1336 | }); |
| 1337 | return (0); |
| 1338 | } |
| 1339 | |
| 1340 | int getpeername(int sk, struct sockaddr *sa, socklen_t *len) |
| 1341 | { |
| 1342 | PRESERVING_ERRNO({ |
| 1343 | char sabuf[1024]; |
| 1344 | socklen_t mylen = sizeof(sabuf); |
| 1345 | if (real_getpeername(sk, SA(sabuf), &mylen)) |
| 1346 | return (-1); |
| 1347 | return_fake_name(SA(sabuf), mylen, sa, len); |
| 1348 | }); |
| 1349 | return (0); |
| 1350 | } |
| 1351 | |
| 1352 | int getsockopt(int sk, int lev, int opt, void *p, socklen_t *len) |
| 1353 | { |
| 1354 | switch (lev) { |
| 1355 | case SOL_IP: |
| 1356 | case SOL_TCP: |
| 1357 | case SOL_UDP: |
| 1358 | if (*len > 0) |
| 1359 | memset(p, 0, *len); |
| 1360 | return (0); |
| 1361 | } |
| 1362 | return (real_getsockopt(sk, lev, opt, p, len)); |
| 1363 | } |
| 1364 | |
| 1365 | int setsockopt(int sk, int lev, int opt, const void *p, socklen_t len) |
| 1366 | { |
| 1367 | switch (lev) { |
| 1368 | case SOL_IP: |
| 1369 | case SOL_TCP: |
| 1370 | case SOL_UDP: |
| 1371 | return (0); |
| 1372 | } |
| 1373 | switch (opt) { |
| 1374 | case SO_BINDTODEVICE: |
| 1375 | case SO_ATTACH_FILTER: |
| 1376 | case SO_DETACH_FILTER: |
| 1377 | return (0); |
| 1378 | } |
| 1379 | return (real_setsockopt(sk, lev, opt, p, len)); |
| 1380 | } |
| 1381 | |
| 1382 | int ioctl(int fd, unsigned long op, ...) |
| 1383 | { |
| 1384 | va_list ap; |
| 1385 | void *arg; |
| 1386 | int sk; |
| 1387 | int rc; |
| 1388 | |
| 1389 | va_start(ap, op); |
| 1390 | arg = va_arg(ap, void *); |
| 1391 | |
| 1392 | switch (op) { |
| 1393 | case SIOCGIFADDR: |
| 1394 | case SIOCGIFBRDADDR: |
| 1395 | case SIOCGIFDSTADDR: |
| 1396 | case SIOCGIFNETMASK: |
| 1397 | PRESERVING_ERRNO({ |
| 1398 | if (fixup_real_ip_socket(fd, AF_INET, &sk)) goto real; |
| 1399 | }); |
| 1400 | rc = real_ioctl(sk, op, arg); |
| 1401 | PRESERVING_ERRNO({ close(sk); }); |
| 1402 | break; |
| 1403 | default: |
| 1404 | real: |
| 1405 | rc = real_ioctl(fd, op, arg); |
| 1406 | break; |
| 1407 | } |
| 1408 | va_end(ap); |
| 1409 | return (rc); |
| 1410 | } |
| 1411 | |
| 1412 | /*----- Initialization ----------------------------------------------------*/ |
| 1413 | |
| 1414 | /* Clean up the socket directory, deleting stale sockets. */ |
| 1415 | static void cleanup_sockdir(void) |
| 1416 | { |
| 1417 | DIR *dir; |
| 1418 | struct dirent *d; |
| 1419 | address addr; |
| 1420 | struct sockaddr_un sun; |
| 1421 | struct stat st; |
| 1422 | Dpid; |
| 1423 | |
| 1424 | if ((dir = opendir(sockdir)) == 0) return; |
| 1425 | sun.sun_family = AF_UNIX; |
| 1426 | while ((d = readdir(dir)) != 0) { |
| 1427 | if (d->d_name[0] == '.') continue; |
| 1428 | snprintf(sun.sun_path, sizeof(sun.sun_path), |
| 1429 | "%s/%s", sockdir, d->d_name); |
| 1430 | if (decode_inet_addr(&addr.sa, 0, &sun, SUN_LEN(&sun)) || |
| 1431 | stat(sun.sun_path, &st) || |
| 1432 | !S_ISSOCK(st.st_mode)) { |
| 1433 | D( fprintf(stderr, "noip(%d): ignoring unknown socketdir entry `%s'\n", |
| 1434 | pid, sun.sun_path); ) |
| 1435 | continue; |
| 1436 | } |
| 1437 | if (unix_socket_status(&sun, 0) == STALE) { |
| 1438 | D( fprintf(stderr, "noip(%d): clearing away stale socket %s\n", |
| 1439 | pid, d->d_name); ) |
| 1440 | unlink(sun.sun_path); |
| 1441 | } |
| 1442 | } |
| 1443 | closedir(dir); |
| 1444 | } |
| 1445 | |
| 1446 | /* Find the addresses attached to local network interfaces, and remember them |
| 1447 | * in a table. |
| 1448 | */ |
| 1449 | static void get_local_ipaddrs(void) |
| 1450 | { |
| 1451 | struct ifaddrs *ifa_head, *ifa; |
| 1452 | ipaddr a; |
| 1453 | int i; |
| 1454 | Dpid; |
| 1455 | |
| 1456 | D( fprintf(stderr, "noip(%d): fetching local addresses...\n", pid); ) |
| 1457 | if (getifaddrs(&ifa_head)) { perror("getifaddrs"); return; } |
| 1458 | for (n_local_ipaddrs = 0, ifa = ifa_head; |
| 1459 | n_local_ipaddrs < MAX_LOCAL_IPADDRS && ifa; |
| 1460 | ifa = ifa->ifa_next) { |
| 1461 | if (!ifa->ifa_addr || !family_known_p(ifa->ifa_addr->sa_family)) |
| 1462 | continue; |
| 1463 | ipaddr_from_sockaddr(&a, ifa->ifa_addr); |
| 1464 | D({ char buf[ADDRBUFSZ]; |
| 1465 | fprintf(stderr, "noip(%d): local addr %s = %s", pid, |
| 1466 | ifa->ifa_name, |
| 1467 | inet_ntop(ifa->ifa_addr->sa_family, &a, |
| 1468 | buf, sizeof(buf))); }) |
| 1469 | for (i = 0; i < n_local_ipaddrs; i++) { |
| 1470 | if (ifa->ifa_addr->sa_family == local_ipaddrs[i].af && |
| 1471 | ipaddr_equal_p(local_ipaddrs[i].af, &a, &local_ipaddrs[i].addr)) { |
| 1472 | D( fprintf(stderr, " (duplicate)\n"); ) |
| 1473 | goto skip; |
| 1474 | } |
| 1475 | } |
| 1476 | D( fprintf(stderr, "\n"); ) |
| 1477 | local_ipaddrs[n_local_ipaddrs].af = ifa->ifa_addr->sa_family; |
| 1478 | local_ipaddrs[n_local_ipaddrs].addr = a; |
| 1479 | n_local_ipaddrs++; |
| 1480 | skip:; |
| 1481 | } |
| 1482 | freeifaddrs(ifa_head); |
| 1483 | } |
| 1484 | |
| 1485 | /* Print the given message to standard error. Avoids stdio. */ |
| 1486 | static void printerr(const char *p) |
| 1487 | { if (write(STDERR_FILENO, p, strlen(p))) ; } |
| 1488 | |
| 1489 | /* Create the socket directory, being careful about permissions. */ |
| 1490 | static void create_sockdir(void) |
| 1491 | { |
| 1492 | struct stat st; |
| 1493 | |
| 1494 | if (lstat(sockdir, &st)) { |
| 1495 | if (errno == ENOENT) { |
| 1496 | if (mkdir(sockdir, 0700)) { |
| 1497 | perror("noip: creating socketdir"); |
| 1498 | exit(127); |
| 1499 | } |
| 1500 | if (!lstat(sockdir, &st)) |
| 1501 | goto check; |
| 1502 | } |
| 1503 | perror("noip: checking socketdir"); |
| 1504 | exit(127); |
| 1505 | } |
| 1506 | check: |
| 1507 | if (!S_ISDIR(st.st_mode)) { |
| 1508 | printerr("noip: bad socketdir: not a directory\n"); |
| 1509 | exit(127); |
| 1510 | } |
| 1511 | if (st.st_uid != uid) { |
| 1512 | printerr("noip: bad socketdir: not owner\n"); |
| 1513 | exit(127); |
| 1514 | } |
| 1515 | if (st.st_mode & 077) { |
| 1516 | printerr("noip: bad socketdir: not private\n"); |
| 1517 | exit(127); |
| 1518 | } |
| 1519 | } |
| 1520 | |
| 1521 | /* Initialization function. */ |
| 1522 | static void setup(void) __attribute__((constructor)); |
| 1523 | static void setup(void) |
| 1524 | { |
| 1525 | PRESERVING_ERRNO({ |
| 1526 | char *p; |
| 1527 | |
| 1528 | import(); |
| 1529 | uid = geteuid(); |
| 1530 | if ((p = getenv("NOIP_DEBUG")) && atoi(p)) |
| 1531 | debug = 1; |
| 1532 | get_local_ipaddrs(); |
| 1533 | readconfig(); |
| 1534 | create_sockdir(); |
| 1535 | cleanup_sockdir(); |
| 1536 | }); |
| 1537 | } |
| 1538 | |
| 1539 | /*----- That's all, folks -------------------------------------------------*/ |