| 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 distributed in the hope that it will be useful, but WITHOUT |
| 18 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 19 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for |
| 20 | * more details. |
| 21 | * |
| 22 | * You should have received a copy of the GNU General Public License along |
| 23 | * with mLib; if not, write to the Free Software Foundation, Inc., 59 Temple |
| 24 | * 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 <ctype.h> |
| 35 | #include <errno.h> |
| 36 | #include <stdio.h> |
| 37 | #include <stdlib.h> |
| 38 | |
| 39 | #include <unistd.h> |
| 40 | #include <dirent.h> |
| 41 | #include <dlfcn.h> |
| 42 | #include <fcntl.h> |
| 43 | #include <pwd.h> |
| 44 | |
| 45 | #include <sys/ioctl.h> |
| 46 | #include <sys/socket.h> |
| 47 | #include <sys/stat.h> |
| 48 | #include <sys/un.h> |
| 49 | |
| 50 | #include <netinet/in.h> |
| 51 | #include <arpa/inet.h> |
| 52 | #include <netinet/tcp.h> |
| 53 | #include <netinet/udp.h> |
| 54 | #include <net/if.h> |
| 55 | |
| 56 | /*----- Data structures ---------------------------------------------------*/ |
| 57 | |
| 58 | enum { UNUSED, STALE, USED }; /* Unix socket status values */ |
| 59 | enum { WANT_FRESH, WANT_EXISTING }; /* Socket address dispositions */ |
| 60 | enum { DENY, ALLOW }; /* ACL verdicts */ |
| 61 | |
| 62 | /* Access control list nodes */ |
| 63 | typedef struct aclnode { |
| 64 | struct aclnode *next; |
| 65 | int act; |
| 66 | unsigned long minaddr, maxaddr; |
| 67 | unsigned short minport, maxport; |
| 68 | } aclnode; |
| 69 | |
| 70 | /* Local address records */ |
| 71 | #define MAX_LOCAL_IPADDRS 16 |
| 72 | static struct in_addr local_ipaddrs[MAX_LOCAL_IPADDRS]; |
| 73 | static int n_local_ipaddrs; |
| 74 | |
| 75 | /* General configuration */ |
| 76 | static uid_t uid; |
| 77 | static char *sockdir = 0; |
| 78 | static int debug = 0; |
| 79 | static unsigned minautoport = 16384, maxautoport = 65536; |
| 80 | |
| 81 | /* Access control lists */ |
| 82 | static aclnode *bind_real, **bind_tail = &bind_real; |
| 83 | static aclnode *connect_real, **connect_tail = &connect_real; |
| 84 | |
| 85 | /*----- Import the real versions of functions -----------------------------*/ |
| 86 | |
| 87 | /* The list of functions to immport. */ |
| 88 | #define IMPORTS(_) \ |
| 89 | _(socket, int, (int, int, int)) \ |
| 90 | _(socketpair, int, (int, int, int, int *)) \ |
| 91 | _(connect, int, (int, const struct sockaddr *, socklen_t)) \ |
| 92 | _(bind, int, (int, const struct sockaddr *, socklen_t)) \ |
| 93 | _(accept, int, (int, struct sockaddr *, socklen_t *)) \ |
| 94 | _(getsockname, int, (int, struct sockaddr *, socklen_t *)) \ |
| 95 | _(getpeername, int, (int, struct sockaddr *, socklen_t *)) \ |
| 96 | _(getsockopt, int, (int, int, int, void *, socklen_t *)) \ |
| 97 | _(setsockopt, int, (int, int, int, const void *, socklen_t)) \ |
| 98 | _(sendto, ssize_t, (int, const void *buf, size_t, int, \ |
| 99 | const struct sockaddr *to, socklen_t tolen)) \ |
| 100 | _(recvfrom, ssize_t, (int, void *buf, size_t, int, \ |
| 101 | struct sockaddr *from, socklen_t *fromlen)) \ |
| 102 | _(sendmsg, ssize_t, (int, const struct msghdr *, int)) \ |
| 103 | _(recvmsg, ssize_t, (int, struct msghdr *, int)) |
| 104 | |
| 105 | /* Function pointers to set up. */ |
| 106 | #define DECL(imp, ret, args) static ret (*real_##imp) args; |
| 107 | IMPORTS(DECL) |
| 108 | #undef DECL |
| 109 | |
| 110 | /* Import the system calls. */ |
| 111 | static void import(void) |
| 112 | { |
| 113 | #define IMPORT(imp, ret, args) \ |
| 114 | real_##imp = (ret (*)args)dlsym(RTLD_NEXT, #imp); |
| 115 | IMPORTS(IMPORT) |
| 116 | #undef IMPORT |
| 117 | } |
| 118 | |
| 119 | /*----- Utilities ---------------------------------------------------------*/ |
| 120 | |
| 121 | /* Socket address casts */ |
| 122 | #define SA(sa) ((struct sockaddr *)(sa)) |
| 123 | #define SIN(sa) ((struct sockaddr_in *)(sa)) |
| 124 | #define SUN(sa) ((struct sockaddr_un *)(sa)) |
| 125 | |
| 126 | /* Raw bytes */ |
| 127 | #define UC(ch) ((unsigned char)(ch)) |
| 128 | |
| 129 | /* Memory allocation */ |
| 130 | #define NEW(x) ((x) = xmalloc(sizeof(*x))) |
| 131 | #define NEWV(x, n) ((x) = xmalloc(sizeof(*x) * (n))) |
| 132 | |
| 133 | /* Debugging */ |
| 134 | #ifdef DEBUG |
| 135 | # define D(body) { if (debug) { body } } |
| 136 | #else |
| 137 | # define D(body) ; |
| 138 | #endif |
| 139 | |
| 140 | /* Preservation of error status */ |
| 141 | #define PRESERVING_ERRNO(body) do { \ |
| 142 | int _err = errno; { body } errno = _err; \ |
| 143 | } while (0) |
| 144 | |
| 145 | /* Allocate N bytes of memory; abort on failure. */ |
| 146 | static void *xmalloc(size_t n) |
| 147 | { |
| 148 | void *p; |
| 149 | if (!n) return (0); |
| 150 | if ((p = malloc(n)) == 0) { perror("malloc"); exit(127); } |
| 151 | return (p); |
| 152 | } |
| 153 | |
| 154 | /* Allocate a copy of the null-terminated string P; abort on failure. */ |
| 155 | static char *xstrdup(const char *p) |
| 156 | { |
| 157 | size_t n = strlen(p) + 1; |
| 158 | char *q = xmalloc(n); |
| 159 | memcpy(q, p, n); |
| 160 | return (q); |
| 161 | } |
| 162 | /*----- Access control lists ----------------------------------------------*/ |
| 163 | |
| 164 | #ifdef DEBUG |
| 165 | |
| 166 | /* Write to standard error a description of the ACL node A. */ |
| 167 | static void dump_aclnode(aclnode *a) |
| 168 | { |
| 169 | char minbuf[16], maxbuf[16]; |
| 170 | struct in_addr amin, amax; |
| 171 | |
| 172 | amin.s_addr = htonl(a->minaddr); |
| 173 | amax.s_addr = htonl(a->maxaddr); |
| 174 | fprintf(stderr, "noip: %c ", a->act ? '+' : '-'); |
| 175 | if (a->minaddr == 0 && a->maxaddr == 0xffffffff) |
| 176 | fprintf(stderr, "any"); |
| 177 | else { |
| 178 | fprintf(stderr, "%s", |
| 179 | inet_ntop(AF_INET, &amin, minbuf, sizeof(minbuf))); |
| 180 | if (a->maxaddr != a->minaddr) { |
| 181 | fprintf(stderr, "-%s", |
| 182 | inet_ntop(AF_INET, &amax, maxbuf, sizeof(maxbuf))); |
| 183 | } |
| 184 | } |
| 185 | if (a->minport != 0 || a->maxport != 0xffff) { |
| 186 | fprintf(stderr, ":%u", (unsigned)a->minport); |
| 187 | if (a->minport != a->maxport) |
| 188 | fprintf(stderr, "-%u", (unsigned)a->maxport); |
| 189 | } |
| 190 | fputc('\n', stderr); |
| 191 | } |
| 192 | |
| 193 | static void dump_acl(aclnode *a) |
| 194 | { |
| 195 | int act = ALLOW; |
| 196 | |
| 197 | for (; a; a = a->next) { |
| 198 | dump_aclnode(a); |
| 199 | act = a->act; |
| 200 | } |
| 201 | fprintf(stderr, "noip: [default policy: %s]\n", |
| 202 | act == ALLOW ? "DENY" : "ALLOW"); |
| 203 | } |
| 204 | |
| 205 | #endif |
| 206 | |
| 207 | /* Returns nonzero if the ACL A allows the IP socket SIN. */ |
| 208 | static int acl_allows_p(aclnode *a, const struct sockaddr_in *sin) |
| 209 | { |
| 210 | unsigned long addr = ntohl(sin->sin_addr.s_addr); |
| 211 | unsigned short port = ntohs(sin->sin_port); |
| 212 | int act = ALLOW; |
| 213 | |
| 214 | D( char buf[16]; |
| 215 | fprintf(stderr, "noip: check %s:%u\n", |
| 216 | inet_ntop(AF_INET, &sin->sin_addr, buf, sizeof(buf)), |
| 217 | ntohs((unsigned)sin->sin_port)); ) |
| 218 | for (; a; a = a->next) { |
| 219 | D( dump_aclnode(a); ) |
| 220 | if (a->minaddr <= addr && addr <= a->maxaddr && |
| 221 | a->minport <= port && port <= a->maxport) { |
| 222 | D( fprintf(stderr, "noip: aha! %s\n", a->act ? "ALLOW" : "DENY"); ) |
| 223 | return (a->act); |
| 224 | } |
| 225 | act = a->act; |
| 226 | } |
| 227 | D( fprintf(stderr, "noip: nothing found: %s\n", act ? "DENY" : "ALLOW"); ) |
| 228 | return (!act); |
| 229 | } |
| 230 | |
| 231 | /*----- Socket address conversion -----------------------------------------*/ |
| 232 | |
| 233 | /* Return a uniformly distributed integer between MIN and MAX inclusive. */ |
| 234 | static unsigned randrange(unsigned min, unsigned max) |
| 235 | { |
| 236 | unsigned mask, i; |
| 237 | |
| 238 | /* It's so nice not to have to care about the quality of the generator |
| 239 | much! */ |
| 240 | max -= min; |
| 241 | for (mask = 1; mask < max; mask = (mask << 1) | 1) |
| 242 | ; |
| 243 | do i = rand() & mask; while (i > max); |
| 244 | return (i + min); |
| 245 | } |
| 246 | |
| 247 | /* Return the status of Unix-domain socket address SUN. Returns: UNUSED if |
| 248 | * the socket doesn't exist; USED if the path refers to an active socket, or |
| 249 | * isn't really a socket at all, or we can't tell without a careful search |
| 250 | * and QUICKP is set; or STALE if the file refers to a socket which isn't |
| 251 | * being used any more. |
| 252 | */ |
| 253 | static int unix_socket_status(struct sockaddr_un *sun, int quickp) |
| 254 | { |
| 255 | struct stat st; |
| 256 | FILE *fp = 0; |
| 257 | size_t len, n; |
| 258 | int rc; |
| 259 | char buf[256]; |
| 260 | |
| 261 | if (stat(sun->sun_path, &st)) |
| 262 | return (errno == ENOENT ? UNUSED : USED); |
| 263 | if (!S_ISSOCK(st.st_mode) || quickp) |
| 264 | return (USED); |
| 265 | rc = USED; |
| 266 | if ((fp = fopen("/proc/net/unix", "r")) == 0) |
| 267 | goto done; |
| 268 | if (!fgets(buf, sizeof(buf), fp)) goto done; /* skip header */ |
| 269 | len = strlen(sun->sun_path); |
| 270 | while (fgets(buf, sizeof(buf), fp)) { |
| 271 | n = strlen(buf); |
| 272 | if (n >= len + 2 && buf[n - len - 2] == ' ' && buf[n - 1] == '\n' && |
| 273 | memcmp(buf + n - len - 1, sun->sun_path, len) == 0) |
| 274 | goto done; |
| 275 | } |
| 276 | if (ferror(fp)) |
| 277 | goto done; |
| 278 | rc = STALE; |
| 279 | done: |
| 280 | if (fp) fclose(fp); |
| 281 | return (rc); |
| 282 | } |
| 283 | |
| 284 | /* Encode the Internet address SIN as a Unix-domain address SUN. If WANT is |
| 285 | * WANT_FRESH, and SIN->sin_port is zero, then we pick an arbitrary local |
| 286 | * port. Otherwise we pick the port given. There's an unpleasant hack to |
| 287 | * find servers bound to INADDR_ANY. Returns zero on success; -1 on failure. |
| 288 | */ |
| 289 | static int encode_inet_addr(struct sockaddr_un *sun, |
| 290 | const struct sockaddr_in *sin, |
| 291 | int want) |
| 292 | { |
| 293 | int i; |
| 294 | int desperatep = 0; |
| 295 | char buf[INET_ADDRSTRLEN]; |
| 296 | int rc; |
| 297 | |
| 298 | D( fprintf(stderr, "noip: encode %s:%u (%s)", |
| 299 | inet_ntop(AF_INET, &sin->sin_addr, buf, sizeof(buf)), |
| 300 | (unsigned)ntohs(sin->sin_port), |
| 301 | want == WANT_EXISTING ? "EXISTING" : "FRESH"); ) |
| 302 | sun->sun_family = AF_UNIX; |
| 303 | if (sin->sin_port || want == WANT_EXISTING) { |
| 304 | snprintf(sun->sun_path, sizeof(sun->sun_path), "%s/%s:%u", sockdir, |
| 305 | inet_ntop(AF_INET, &sin->sin_addr, buf, sizeof(buf)), |
| 306 | (unsigned)ntohs(sin->sin_port)); |
| 307 | rc = unix_socket_status(sun, 0); |
| 308 | if (rc == STALE) unlink(sun->sun_path); |
| 309 | if (rc != USED && want == WANT_EXISTING) { |
| 310 | snprintf(sun->sun_path, sizeof(sun->sun_path), "%s/0.0.0.0:%u", |
| 311 | sockdir, (unsigned)ntohs(sin->sin_port)); |
| 312 | if (unix_socket_status(sun, 0) == STALE) unlink(sun->sun_path); |
| 313 | } |
| 314 | } else { |
| 315 | for (i = 0; i < 10; i++) { |
| 316 | snprintf(sun->sun_path, sizeof(sun->sun_path), "%s/%s:%u", sockdir, |
| 317 | inet_ntop(AF_INET, &sin->sin_addr, buf, sizeof(buf)), |
| 318 | randrange(minautoport, maxautoport)); |
| 319 | if (unix_socket_status(sun, 1) == UNUSED) goto found; |
| 320 | } |
| 321 | for (desperatep = 0; desperatep < 2; desperatep++) { |
| 322 | for (i = minautoport; i <= maxautoport; i++) { |
| 323 | snprintf(sun->sun_path, sizeof(sun->sun_path), "%s/%s:%u", sockdir, |
| 324 | inet_ntop(AF_INET, &sin->sin_addr, buf, sizeof(buf)), |
| 325 | (unsigned)i); |
| 326 | rc = unix_socket_status(sun, !desperatep); |
| 327 | switch (rc) { |
| 328 | case STALE: unlink(sun->sun_path); |
| 329 | case UNUSED: goto found; |
| 330 | } |
| 331 | } |
| 332 | } |
| 333 | errno = EADDRINUSE; |
| 334 | D( fprintf(stderr, " -- can't resolve\n"); ) |
| 335 | return (-1); |
| 336 | found:; |
| 337 | } |
| 338 | D( fprintf(stderr, " -> `%s'\n", sun->sun_path); ) |
| 339 | return (0); |
| 340 | } |
| 341 | |
| 342 | /* Decode the Unix address SUN to an Internet address SIN. If |
| 343 | * DECODE_UNBOUND_P is nonzero, an empty address (indicative of an unbound |
| 344 | * Unix-domain socket) is translated to a wildcard Internet address. Returns |
| 345 | * zero on success; -1 on failure (e.g., it wasn't one of our addresses). |
| 346 | */ |
| 347 | static int decode_inet_addr(struct sockaddr_in *sin, |
| 348 | const struct sockaddr_un *sun, |
| 349 | socklen_t len, |
| 350 | int decode_unbound_p) |
| 351 | { |
| 352 | char buf[INET_ADDRSTRLEN + 16]; |
| 353 | char *p; |
| 354 | size_t n = strlen(sockdir), nn; |
| 355 | struct sockaddr_in sin_mine; |
| 356 | unsigned long port; |
| 357 | |
| 358 | if (!sin) |
| 359 | sin = &sin_mine; |
| 360 | if (sun->sun_family != AF_UNIX) |
| 361 | return (-1); |
| 362 | nn = strlen(sun->sun_path); |
| 363 | if (len < sizeof(sun)) ((char *)sun)[len] = 0; |
| 364 | D( fprintf(stderr, "noip: decode (%d) `%s'", |
| 365 | *sun->sun_path, sun->sun_path); ) |
| 366 | if (decode_unbound_p && !sun->sun_path[0]) { |
| 367 | sin->sin_family = AF_INET; |
| 368 | sin->sin_addr.s_addr = INADDR_ANY; |
| 369 | sin->sin_port = 0; |
| 370 | D( fprintf(stderr, " -- unbound socket\n"); ) |
| 371 | return (0); |
| 372 | } |
| 373 | if (nn < n + 1 || nn - n >= sizeof(buf) || sun->sun_path[n] != '/' || |
| 374 | memcmp(sun->sun_path, sockdir, n) != 0) { |
| 375 | D( fprintf(stderr, " -- not one of ours\n"); ) |
| 376 | return (-1); |
| 377 | } |
| 378 | memcpy(buf, sun->sun_path + n + 1, nn - n); |
| 379 | if ((p = strchr(buf, ':')) == 0) { |
| 380 | D( fprintf(stderr, " -- malformed (no port)\n"); ) |
| 381 | return (-1); |
| 382 | } |
| 383 | *p++ = 0; |
| 384 | sin->sin_family = AF_INET; |
| 385 | if (inet_pton(AF_INET, buf, &sin->sin_addr) <= 0) { |
| 386 | D( fprintf(stderr, " -- malformed (bad address `%s')\n", buf); ) |
| 387 | return (-1); |
| 388 | } |
| 389 | port = strtoul(p, &p, 10); |
| 390 | if (*p || port >= 65536) { |
| 391 | D( fprintf(stderr, " -- malformed (port out of range)"); ) |
| 392 | return (-1); |
| 393 | } |
| 394 | sin->sin_port = htons(port); |
| 395 | D( fprintf(stderr, " -> %s:%u\n", |
| 396 | inet_ntop(AF_INET, &sin->sin_addr, buf, sizeof(buf)), |
| 397 | (unsigned)port); ) |
| 398 | return (0); |
| 399 | } |
| 400 | |
| 401 | /* SK is (or at least might be) a Unix-domain socket we created when an |
| 402 | * Internet socket was asked for. We've decided it should be an Internet |
| 403 | * socket after all, so convert it. |
| 404 | */ |
| 405 | static int fixup_real_ip_socket(int sk) |
| 406 | { |
| 407 | int nsk; |
| 408 | int type; |
| 409 | int f, fd; |
| 410 | struct sockaddr_un sun; |
| 411 | struct sockaddr_in sin; |
| 412 | socklen_t len; |
| 413 | |
| 414 | #define OPTS(_) \ |
| 415 | _(DEBUG, int) \ |
| 416 | _(REUSEADDR, int) \ |
| 417 | _(DONTROUTE, int) \ |
| 418 | _(BROADCAST, int) \ |
| 419 | _(SNDBUF, int) \ |
| 420 | _(RCVBUF, int) \ |
| 421 | _(OOBINLINE, int) \ |
| 422 | _(NO_CHECK, int) \ |
| 423 | _(LINGER, struct linger) \ |
| 424 | _(BSDCOMPAT, int) \ |
| 425 | _(RCVLOWAT, int) \ |
| 426 | _(RCVTIMEO, struct timeval) \ |
| 427 | _(SNDTIMEO, struct timeval) |
| 428 | |
| 429 | len = sizeof(sun); |
| 430 | if (real_getsockname(sk, SA(&sun), &len)) |
| 431 | return (-1); |
| 432 | if (decode_inet_addr(&sin, &sun, len, 1)) |
| 433 | return (0); /* Not one of ours */ |
| 434 | len = sizeof(type); |
| 435 | if (real_getsockopt(sk, SOL_SOCKET, SO_TYPE, &type, &len) < 0 || |
| 436 | (nsk = real_socket(PF_INET, type, 0)) < 0) |
| 437 | return (-1); |
| 438 | #define FIX(opt, ty) do { \ |
| 439 | ty ov_; \ |
| 440 | len = sizeof(ov_); \ |
| 441 | if (real_getsockopt(sk, SOL_SOCKET, SO_##opt, &ov_, &len) < 0 || \ |
| 442 | real_setsockopt(nsk, SOL_SOCKET, SO_##opt, &ov_, len)) { \ |
| 443 | close(nsk); \ |
| 444 | return (-1); \ |
| 445 | } \ |
| 446 | } while (0); |
| 447 | OPTS(FIX) |
| 448 | #undef FIX |
| 449 | if ((f = fcntl(sk, F_GETFL)) < 0 || |
| 450 | (fd = fcntl(sk, F_GETFD)) < 0 || |
| 451 | fcntl(nsk, F_SETFL, f) < 0 || |
| 452 | dup2(nsk, sk) < 0) { |
| 453 | close(nsk); |
| 454 | return (-1); |
| 455 | } |
| 456 | unlink(sun.sun_path); |
| 457 | close(nsk); |
| 458 | if (fcntl(sk, F_SETFD, fd) < 0) { |
| 459 | perror("noip: fixup_real_ip_socket F_SETFD"); |
| 460 | abort(); |
| 461 | } |
| 462 | return (0); |
| 463 | } |
| 464 | |
| 465 | /* The socket SK is about to be used to communicate with the remote address |
| 466 | * SA. Assign it a local address so that getpeername does something useful. |
| 467 | */ |
| 468 | static int do_implicit_bind(int sk, const struct sockaddr **sa, |
| 469 | socklen_t *len, struct sockaddr_un *sun) |
| 470 | { |
| 471 | struct sockaddr_in sin; |
| 472 | socklen_t mylen = sizeof(*sun); |
| 473 | |
| 474 | if (acl_allows_p(connect_real, SIN(*sa))) { |
| 475 | if (fixup_real_ip_socket(sk)) |
| 476 | return (-1); |
| 477 | } else { |
| 478 | if (real_getsockname(sk, SA(sun), &mylen) < 0) |
| 479 | return (-1); |
| 480 | if (sun->sun_family == AF_UNIX) { |
| 481 | if (mylen < sizeof(*sun)) ((char *)sun)[mylen] = 0; |
| 482 | if (!sun->sun_path[0]) { |
| 483 | sin.sin_family = AF_INET; |
| 484 | sin.sin_addr.s_addr = htonl(INADDR_LOOPBACK); |
| 485 | sin.sin_port = 0; |
| 486 | encode_inet_addr(sun, &sin, WANT_FRESH); |
| 487 | if (real_bind(sk, SA(sun), SUN_LEN(sun))) |
| 488 | return (-1); |
| 489 | } |
| 490 | encode_inet_addr(sun, SIN(*sa), WANT_EXISTING); |
| 491 | *sa = SA(sun); |
| 492 | *len = SUN_LEN(sun); |
| 493 | } |
| 494 | } |
| 495 | return (0); |
| 496 | } |
| 497 | |
| 498 | /* We found the real address SA, with length LEN; if it's a Unix-domain |
| 499 | * address corresponding to a fake socket, convert it to cover up the |
| 500 | * deception. Whatever happens, put the result at FAKE and store its length |
| 501 | * at FAKELEN. |
| 502 | */ |
| 503 | static void return_fake_name(struct sockaddr *sa, socklen_t len, |
| 504 | struct sockaddr *fake, socklen_t *fakelen) |
| 505 | { |
| 506 | struct sockaddr_in sin; |
| 507 | socklen_t alen; |
| 508 | |
| 509 | if (sa->sa_family == AF_UNIX && |
| 510 | !decode_inet_addr(&sin, SUN(sa), len, 0)) { |
| 511 | sa = SA(&sin); |
| 512 | len = sizeof(sin); |
| 513 | } |
| 514 | alen = len; |
| 515 | if (len > *fakelen) |
| 516 | len = *fakelen; |
| 517 | if (len > 0) |
| 518 | memcpy(fake, sa, len); |
| 519 | *fakelen = alen; |
| 520 | } |
| 521 | |
| 522 | /*----- Configuration -----------------------------------------------------*/ |
| 523 | |
| 524 | /* Return the process owner's home directory. */ |
| 525 | static char *home(void) |
| 526 | { |
| 527 | char *p; |
| 528 | struct passwd *pw; |
| 529 | |
| 530 | if (getuid() == uid && |
| 531 | (p = getenv("HOME")) != 0) |
| 532 | return (p); |
| 533 | else if ((pw = getpwuid(uid)) != 0) |
| 534 | return (pw->pw_dir); |
| 535 | else |
| 536 | return "/notexist"; |
| 537 | } |
| 538 | |
| 539 | /* Return a good temporary directory to use. */ |
| 540 | static char *tmpdir(void) |
| 541 | { |
| 542 | char *p; |
| 543 | |
| 544 | if ((p = getenv("TMPDIR")) != 0) return (p); |
| 545 | else if ((p = getenv("TMP")) != 0) return (p); |
| 546 | else return ("/tmp"); |
| 547 | } |
| 548 | |
| 549 | /* Return the user's name, or at least something distinctive. */ |
| 550 | static char *user(void) |
| 551 | { |
| 552 | static char buf[16]; |
| 553 | char *p; |
| 554 | struct passwd *pw; |
| 555 | |
| 556 | if ((p = getenv("USER")) != 0) return (p); |
| 557 | else if ((p = getenv("LOGNAME")) != 0) return (p); |
| 558 | else if ((pw = getpwuid(uid)) != 0) return (pw->pw_name); |
| 559 | else { |
| 560 | snprintf(buf, sizeof(buf), "uid-%lu", (unsigned long)uid); |
| 561 | return (buf); |
| 562 | } |
| 563 | } |
| 564 | |
| 565 | /* Skip P over space characters. */ |
| 566 | #define SKIPSPC do { while (*p && isspace(UC(*p))) p++; } while (0) |
| 567 | |
| 568 | /* Set Q to point to the next word following P, null-terminate it, and step P |
| 569 | * past it. */ |
| 570 | #define NEXTWORD(q) do { \ |
| 571 | SKIPSPC; \ |
| 572 | q = p; \ |
| 573 | while (*p && !isspace(UC(*p))) p++; \ |
| 574 | if (*p) *p++ = 0; \ |
| 575 | } while (0) |
| 576 | |
| 577 | /* Set Q to point to the next dotted-quad address, store the ending delimiter |
| 578 | * in DEL, null-terminate it, and step P past it. */ |
| 579 | #define NEXTADDR(q, del) do { \ |
| 580 | SKIPSPC; \ |
| 581 | q = p; \ |
| 582 | while (*p && (*p == '.' || isdigit(UC(*p)))) p++; \ |
| 583 | del = *p; \ |
| 584 | if (*p) *p++ = 0; \ |
| 585 | } while (0) |
| 586 | |
| 587 | /* Set Q to point to the next decimal number, store the ending delimiter in |
| 588 | * DEL, null-terminate it, and step P past it. */ |
| 589 | #define NEXTNUMBER(q, del) do { \ |
| 590 | SKIPSPC; \ |
| 591 | q = p; \ |
| 592 | while (*p && isdigit(UC(*p))) p++; \ |
| 593 | del = *p; \ |
| 594 | if (*p) *p++ = 0; \ |
| 595 | } while (0) |
| 596 | |
| 597 | /* Push the character DEL back so we scan it again, unless it's zero |
| 598 | * (end-of-file). */ |
| 599 | #define RESCAN(del) do { if (del) *--p = del; } while (0) |
| 600 | |
| 601 | /* Evaluate true if P is pointing to the word KW (and not some longer string |
| 602 | * of which KW is a prefix). */ |
| 603 | |
| 604 | #define KWMATCHP(kw) (strncmp(p, kw, sizeof(kw) - 1) == 0 && \ |
| 605 | !isalnum(UC(p[sizeof(kw) - 1])) && \ |
| 606 | (p += sizeof(kw) - 1)) |
| 607 | |
| 608 | /* Parse a port list, starting at *PP. Port lists have the form |
| 609 | * [:LOW[-HIGH]]: if omitted, all ports are included; if HIGH is omitted, |
| 610 | * it's as if HIGH = LOW. Store LOW in *MIN, HIGH in *MAX and set *PP to the |
| 611 | * rest of the string. |
| 612 | */ |
| 613 | static void parse_ports(char **pp, unsigned short *min, unsigned short *max) |
| 614 | { |
| 615 | char *p = *pp, *q; |
| 616 | int del; |
| 617 | |
| 618 | SKIPSPC; |
| 619 | if (*p != ':') |
| 620 | { *min = 0; *max = 0xffff; } |
| 621 | else { |
| 622 | p++; |
| 623 | NEXTNUMBER(q, del); *min = strtoul(q, 0, 0); RESCAN(del); |
| 624 | SKIPSPC; |
| 625 | if (*p == '-') |
| 626 | { p++; NEXTNUMBER(q, del); *max = strtoul(q, 0, 0); RESCAN(del); } |
| 627 | else |
| 628 | *max = *min; |
| 629 | } |
| 630 | *pp = p; |
| 631 | } |
| 632 | |
| 633 | /* Make a new ACL node. ACT is the verdict; MINADDR and MAXADDR are the |
| 634 | * ranges on IP addresses; MINPORT and MAXPORT are the ranges on port |
| 635 | * numbers; TAIL is the list tail to attach the new node to. |
| 636 | */ |
| 637 | #define ACLNODE(tail_, act_, \ |
| 638 | minaddr_, maxaddr_, minport_, maxport_) do { \ |
| 639 | aclnode *a_; \ |
| 640 | NEW(a_); \ |
| 641 | a_->act = act_; \ |
| 642 | a_->minaddr = minaddr_; a_->maxaddr = maxaddr_; \ |
| 643 | a_->minport = minport_; a_->maxport = maxport_; \ |
| 644 | *tail_ = a_; tail_ = &a_->next; \ |
| 645 | } while (0) |
| 646 | |
| 647 | /* Parse an ACL line. *PP points to the end of the line; *TAIL points to |
| 648 | * the list tail (i.e., the final link in the list). An ACL entry has the |
| 649 | * form +|- [any | local | ADDR | ADDR - ADDR | ADDR/ADDR | ADDR/INT] PORTS |
| 650 | * where PORTS is parsed by parse_ports above; an ACL line consists of a |
| 651 | * comma-separated sequence of entries.. |
| 652 | */ |
| 653 | static void parse_acl_line(char **pp, aclnode ***tail) |
| 654 | { |
| 655 | struct in_addr addr; |
| 656 | unsigned long minaddr, maxaddr, mask; |
| 657 | unsigned short minport, maxport; |
| 658 | int i, n; |
| 659 | int act; |
| 660 | int del; |
| 661 | char *p = *pp; |
| 662 | char *q; |
| 663 | |
| 664 | for (;;) { |
| 665 | SKIPSPC; |
| 666 | if (*p == '+') act = ALLOW; |
| 667 | else if (*p == '-') act = DENY; |
| 668 | else goto bad; |
| 669 | |
| 670 | p++; |
| 671 | SKIPSPC; |
| 672 | if (KWMATCHP("any")) { |
| 673 | minaddr = 0; |
| 674 | maxaddr = 0xffffffff; |
| 675 | goto justone; |
| 676 | } else if (KWMATCHP("local")) { |
| 677 | parse_ports(&p, &minport, &maxport); |
| 678 | ACLNODE(*tail, act, 0, 0, minport, maxport); |
| 679 | ACLNODE(*tail, act, 0xffffffff, 0xffffffff, minport, maxport); |
| 680 | for (i = 0; i < n_local_ipaddrs; i++) { |
| 681 | minaddr = ntohl(local_ipaddrs[i].s_addr); |
| 682 | ACLNODE(*tail, act, minaddr, minaddr, minport, maxport); |
| 683 | } |
| 684 | } else { |
| 685 | if (*p == ':') { |
| 686 | minaddr = 0; |
| 687 | maxaddr = 0xffffffff; |
| 688 | } else { |
| 689 | NEXTADDR(q, del); |
| 690 | if (inet_pton(AF_INET, q, &addr) <= 0) goto bad; |
| 691 | minaddr = ntohl(addr.s_addr); |
| 692 | RESCAN(del); |
| 693 | SKIPSPC; |
| 694 | if (*p == '-') { |
| 695 | p++; |
| 696 | NEXTADDR(q, del); |
| 697 | if (inet_pton(AF_INET, q, &addr) <= 0) goto bad; |
| 698 | RESCAN(del); |
| 699 | maxaddr = ntohl(addr.s_addr); |
| 700 | } else if (*p == '/') { |
| 701 | p++; |
| 702 | NEXTADDR(q, del); |
| 703 | if (strchr(q, '.')) { |
| 704 | if (inet_pton(AF_INET, q, &addr) <= 0) goto bad; |
| 705 | mask = ntohl(addr.s_addr); |
| 706 | } else { |
| 707 | n = strtoul(q, 0, 0); |
| 708 | mask = (~0ul << (32 - n)) & 0xffffffff; |
| 709 | } |
| 710 | RESCAN(del); |
| 711 | minaddr &= mask; |
| 712 | maxaddr = minaddr | (mask ^ 0xffffffff); |
| 713 | } else |
| 714 | maxaddr = minaddr; |
| 715 | } |
| 716 | justone: |
| 717 | parse_ports(&p, &minport, &maxport); |
| 718 | ACLNODE(*tail, act, minaddr, maxaddr, minport, maxport); |
| 719 | } |
| 720 | SKIPSPC; |
| 721 | if (*p != ',') break; |
| 722 | p++; |
| 723 | } |
| 724 | return; |
| 725 | |
| 726 | bad: |
| 727 | D( fprintf(stderr, "noip: bad acl spec (ignored)\n"); ) |
| 728 | return; |
| 729 | } |
| 730 | |
| 731 | /* Parse the autoports configuration directive. Syntax is MIN - MAX. */ |
| 732 | static void parse_autoports(char **pp) |
| 733 | { |
| 734 | char *p = *pp, *q; |
| 735 | unsigned x, y; |
| 736 | int del; |
| 737 | |
| 738 | SKIPSPC; |
| 739 | NEXTNUMBER(q, del); x = strtoul(q, 0, 0); RESCAN(del); |
| 740 | SKIPSPC; |
| 741 | if (*p != '-') goto bad; p++; |
| 742 | NEXTNUMBER(q, del); y = strtoul(q, 0, 0); RESCAN(del); |
| 743 | minautoport = x; maxautoport = y; |
| 744 | return; |
| 745 | |
| 746 | bad: |
| 747 | D( fprintf(stderr, "bad port range (ignored)\n"); ) |
| 748 | return; |
| 749 | } |
| 750 | |
| 751 | /* Parse an ACL from an environment variable VAR, attaching it to the list |
| 752 | * TAIL. */ |
| 753 | static void parse_acl_env(const char *var, aclnode ***tail) |
| 754 | { |
| 755 | char *p, *q; |
| 756 | |
| 757 | if ((p = getenv(var)) != 0) { |
| 758 | p = q = xstrdup(p); |
| 759 | parse_acl_line(&q, tail); |
| 760 | free(p); |
| 761 | } |
| 762 | } |
| 763 | |
| 764 | /* Read the configuration from the config file and environment. */ |
| 765 | static void readconfig(void) |
| 766 | { |
| 767 | FILE *fp; |
| 768 | char buf[1024]; |
| 769 | size_t n; |
| 770 | char *p, *q, *cmd; |
| 771 | |
| 772 | parse_acl_env("NOIP_REALBIND_BEFORE", &bind_tail); |
| 773 | parse_acl_env("NOIP_REALCONNECT_BEFORE", &connect_tail); |
| 774 | if ((p = getenv("NOIP_AUTOPORTS")) != 0) { |
| 775 | p = q = xstrdup(p); |
| 776 | parse_autoports(&q); |
| 777 | free(p); |
| 778 | } |
| 779 | if ((p = getenv("NOIP_CONFIG")) == 0) |
| 780 | snprintf(p = buf, sizeof(buf), "%s/.noip", home()); |
| 781 | D( fprintf(stderr, "noip: config file: %s\n", p); ) |
| 782 | |
| 783 | if ((fp = fopen(p, "r")) == 0) { |
| 784 | D( fprintf(stderr, "noip: couldn't read config: %s\n", |
| 785 | strerror(errno)); ) |
| 786 | goto done; |
| 787 | } |
| 788 | while (fgets(buf, sizeof(buf), fp)) { |
| 789 | n = strlen(buf); |
| 790 | p = buf; |
| 791 | |
| 792 | SKIPSPC; |
| 793 | if (!*p || *p == '#') continue; |
| 794 | while (n && isspace(UC(buf[n - 1]))) n--; |
| 795 | buf[n] = 0; |
| 796 | NEXTWORD(cmd); |
| 797 | SKIPSPC; |
| 798 | |
| 799 | if (strcmp(cmd, "socketdir") == 0) |
| 800 | sockdir = xstrdup(p); |
| 801 | else if (strcmp(cmd, "realbind") == 0) |
| 802 | parse_acl_line(&p, &bind_tail); |
| 803 | else if (strcmp(cmd, "realconnect") == 0) |
| 804 | parse_acl_line(&p, &connect_tail); |
| 805 | else if (strcmp(cmd, "autoports") == 0) |
| 806 | parse_autoports(&p); |
| 807 | else if (strcmp(cmd, "debug") == 0) |
| 808 | debug = *p ? atoi(p) : 1; |
| 809 | else |
| 810 | D( fprintf(stderr, "noip: bad config command %s\n", cmd); ) |
| 811 | } |
| 812 | fclose(fp); |
| 813 | |
| 814 | done: |
| 815 | parse_acl_env("NOIP_REALBIND", &bind_tail); |
| 816 | parse_acl_env("NOIP_REALCONNECT", &connect_tail); |
| 817 | parse_acl_env("NOIP_REALBIND_AFTER", &bind_tail); |
| 818 | parse_acl_env("NOIP_REALCONNECT_AFTER", &connect_tail); |
| 819 | *bind_tail = 0; |
| 820 | *connect_tail = 0; |
| 821 | if (!sockdir) sockdir = getenv("NOIP_SOCKETDIR"); |
| 822 | if (!sockdir) { |
| 823 | snprintf(buf, sizeof(buf), "%s/noip-%s", tmpdir(), user()); |
| 824 | sockdir = xstrdup(buf); |
| 825 | } |
| 826 | D( fprintf(stderr, "noip: socketdir: %s\n", sockdir); |
| 827 | fprintf(stderr, "noip: autoports: %u-%u\n", |
| 828 | minautoport, maxautoport); |
| 829 | fprintf(stderr, "noip: realbind acl:\n"); |
| 830 | dump_acl(bind_real); |
| 831 | fprintf(stderr, "noip: realconnect acl:\n"); |
| 832 | dump_acl(connect_real); ) |
| 833 | } |
| 834 | |
| 835 | /*----- Overridden system calls -------------------------------------------*/ |
| 836 | |
| 837 | int socket(int pf, int ty, int proto) |
| 838 | { |
| 839 | switch (pf) { |
| 840 | case PF_INET: |
| 841 | pf = PF_UNIX; |
| 842 | proto = 0; |
| 843 | case PF_UNIX: |
| 844 | return real_socket(pf, ty, proto); |
| 845 | default: |
| 846 | errno = EAFNOSUPPORT; |
| 847 | return -1; |
| 848 | } |
| 849 | } |
| 850 | |
| 851 | int socketpair(int pf, int ty, int proto, int *sk) |
| 852 | { |
| 853 | if (pf == PF_INET) { |
| 854 | pf = PF_UNIX; |
| 855 | proto = 0; |
| 856 | } |
| 857 | return (real_socketpair(pf, ty, proto, sk)); |
| 858 | } |
| 859 | |
| 860 | int bind(int sk, const struct sockaddr *sa, socklen_t len) |
| 861 | { |
| 862 | struct sockaddr_un sun; |
| 863 | |
| 864 | if (sa->sa_family == AF_INET) { |
| 865 | PRESERVING_ERRNO({ |
| 866 | if (acl_allows_p(bind_real, SIN(sa))) { |
| 867 | if (fixup_real_ip_socket(sk)) |
| 868 | return (-1); |
| 869 | } else { |
| 870 | encode_inet_addr(&sun, SIN(sa), WANT_FRESH); |
| 871 | sa = SA(&sun); |
| 872 | len = SUN_LEN(&sun); |
| 873 | } |
| 874 | }); |
| 875 | } |
| 876 | return real_bind(sk, sa, len); |
| 877 | } |
| 878 | |
| 879 | int connect(int sk, const struct sockaddr *sa, socklen_t len) |
| 880 | { |
| 881 | struct sockaddr_un sun; |
| 882 | int fixup_p = 0; |
| 883 | int rc; |
| 884 | |
| 885 | switch (sa->sa_family) { |
| 886 | case AF_INET: |
| 887 | PRESERVING_ERRNO({ |
| 888 | do_implicit_bind(sk, &sa, &len, &sun); |
| 889 | fixup_p = 1; |
| 890 | }); |
| 891 | rc = real_connect(sk, sa, len); |
| 892 | if (rc < 0) { |
| 893 | switch (errno) { |
| 894 | case ENOENT: errno = ECONNREFUSED; break; |
| 895 | } |
| 896 | } |
| 897 | break; |
| 898 | default: |
| 899 | rc = real_connect(sk, sa, len); |
| 900 | break; |
| 901 | } |
| 902 | return rc; |
| 903 | } |
| 904 | |
| 905 | ssize_t sendto(int sk, const void *buf, size_t len, int flags, |
| 906 | const struct sockaddr *to, socklen_t tolen) |
| 907 | { |
| 908 | struct sockaddr_un sun; |
| 909 | |
| 910 | if (to && to->sa_family == AF_INET) { |
| 911 | PRESERVING_ERRNO({ |
| 912 | do_implicit_bind(sk, &to, &tolen, &sun); |
| 913 | }); |
| 914 | } |
| 915 | return real_sendto(sk, buf, len, flags, to, tolen); |
| 916 | } |
| 917 | |
| 918 | ssize_t recvfrom(int sk, void *buf, size_t len, int flags, |
| 919 | struct sockaddr *from, socklen_t *fromlen) |
| 920 | { |
| 921 | char sabuf[1024]; |
| 922 | socklen_t mylen = sizeof(sabuf); |
| 923 | ssize_t n; |
| 924 | |
| 925 | if (!from) |
| 926 | return real_recvfrom(sk, buf, len, flags, 0, 0); |
| 927 | PRESERVING_ERRNO({ |
| 928 | n = real_recvfrom(sk, buf, len, flags, SA(sabuf), &mylen); |
| 929 | if (n < 0) |
| 930 | return (-1); |
| 931 | return_fake_name(SA(sabuf), mylen, from, fromlen); |
| 932 | }); |
| 933 | return (n); |
| 934 | } |
| 935 | |
| 936 | ssize_t sendmsg(int sk, const struct msghdr *msg, int flags) |
| 937 | { |
| 938 | struct sockaddr_un sun; |
| 939 | const struct sockaddr *sa; |
| 940 | struct msghdr mymsg; |
| 941 | |
| 942 | if (msg->msg_name && SA(msg->msg_name)->sa_family == AF_INET) { |
| 943 | PRESERVING_ERRNO({ |
| 944 | sa = SA(msg->msg_name); |
| 945 | mymsg = *msg; |
| 946 | do_implicit_bind(sk, &sa, &mymsg.msg_namelen, &sun); |
| 947 | mymsg.msg_name = SA(sa); |
| 948 | msg = &mymsg; |
| 949 | }); |
| 950 | } |
| 951 | return real_sendmsg(sk, msg, flags); |
| 952 | } |
| 953 | |
| 954 | ssize_t recvmsg(int sk, struct msghdr *msg, int flags) |
| 955 | { |
| 956 | char sabuf[1024]; |
| 957 | struct sockaddr *sa; |
| 958 | socklen_t len; |
| 959 | ssize_t n; |
| 960 | |
| 961 | if (!msg->msg_name) |
| 962 | return real_recvmsg(sk, msg, flags); |
| 963 | PRESERVING_ERRNO({ |
| 964 | sa = SA(msg->msg_name); |
| 965 | len = msg->msg_namelen; |
| 966 | msg->msg_name = sabuf; |
| 967 | msg->msg_namelen = sizeof(sabuf); |
| 968 | n = real_recvmsg(sk, msg, flags); |
| 969 | if (n < 0) |
| 970 | return (-1); |
| 971 | return_fake_name(SA(sabuf), msg->msg_namelen, sa, &len); |
| 972 | msg->msg_name = sa; |
| 973 | msg->msg_namelen = len; |
| 974 | }); |
| 975 | return (n); |
| 976 | } |
| 977 | |
| 978 | int accept(int sk, struct sockaddr *sa, socklen_t *len) |
| 979 | { |
| 980 | char sabuf[1024]; |
| 981 | socklen_t mylen = sizeof(sabuf); |
| 982 | int nsk = real_accept(sk, SA(sabuf), &mylen); |
| 983 | |
| 984 | if (nsk < 0) |
| 985 | return (-1); |
| 986 | return_fake_name(SA(sabuf), mylen, sa, len); |
| 987 | return (nsk); |
| 988 | } |
| 989 | |
| 990 | int getsockname(int sk, struct sockaddr *sa, socklen_t *len) |
| 991 | { |
| 992 | PRESERVING_ERRNO({ |
| 993 | char sabuf[1024]; |
| 994 | socklen_t mylen = sizeof(sabuf); |
| 995 | if (real_getsockname(sk, SA(sabuf), &mylen)) |
| 996 | return (-1); |
| 997 | return_fake_name(SA(sabuf), mylen, sa, len); |
| 998 | }); |
| 999 | return (0); |
| 1000 | } |
| 1001 | |
| 1002 | int getpeername(int sk, struct sockaddr *sa, socklen_t *len) |
| 1003 | { |
| 1004 | PRESERVING_ERRNO({ |
| 1005 | char sabuf[1024]; |
| 1006 | socklen_t mylen = sizeof(sabuf); |
| 1007 | if (real_getpeername(sk, SA(sabuf), &mylen)) |
| 1008 | return (-1); |
| 1009 | return_fake_name(SA(sabuf), mylen, sa, len); |
| 1010 | }); |
| 1011 | return (0); |
| 1012 | } |
| 1013 | |
| 1014 | int getsockopt(int sk, int lev, int opt, void *p, socklen_t *len) |
| 1015 | { |
| 1016 | switch (lev) { |
| 1017 | case SOL_IP: |
| 1018 | case SOL_TCP: |
| 1019 | case SOL_UDP: |
| 1020 | if (*len > 0) |
| 1021 | memset(p, 0, *len); |
| 1022 | return (0); |
| 1023 | } |
| 1024 | return real_getsockopt(sk, lev, opt, p, len); |
| 1025 | } |
| 1026 | |
| 1027 | int setsockopt(int sk, int lev, int opt, const void *p, socklen_t len) |
| 1028 | { |
| 1029 | switch (lev) { |
| 1030 | case SOL_IP: |
| 1031 | case SOL_TCP: |
| 1032 | case SOL_UDP: |
| 1033 | return (0); |
| 1034 | } |
| 1035 | switch (opt) { |
| 1036 | case SO_BINDTODEVICE: |
| 1037 | case SO_ATTACH_FILTER: |
| 1038 | case SO_DETACH_FILTER: |
| 1039 | return (0); |
| 1040 | } |
| 1041 | return real_setsockopt(sk, lev, opt, p, len); |
| 1042 | } |
| 1043 | |
| 1044 | /*----- Initialization ----------------------------------------------------*/ |
| 1045 | |
| 1046 | /* Clean up the socket directory, deleting stale sockets. */ |
| 1047 | static void cleanup_sockdir(void) |
| 1048 | { |
| 1049 | DIR *dir; |
| 1050 | struct dirent *d; |
| 1051 | struct sockaddr_in sin; |
| 1052 | struct sockaddr_un sun; |
| 1053 | struct stat st; |
| 1054 | |
| 1055 | if ((dir = opendir(sockdir)) == 0) |
| 1056 | return; |
| 1057 | sun.sun_family = AF_UNIX; |
| 1058 | while ((d = readdir(dir)) != 0) { |
| 1059 | if (d->d_name[0] == '.') continue; |
| 1060 | snprintf(sun.sun_path, sizeof(sun.sun_path), |
| 1061 | "%s/%s", sockdir, d->d_name); |
| 1062 | if (decode_inet_addr(&sin, &sun, SUN_LEN(&sun), 0) || |
| 1063 | stat(sun.sun_path, &st) || |
| 1064 | !S_ISSOCK(st.st_mode)) { |
| 1065 | D( fprintf(stderr, "noip: ignoring unknown socketdir entry `%s'\n", |
| 1066 | sun.sun_path); ) |
| 1067 | continue; |
| 1068 | } |
| 1069 | if (unix_socket_status(&sun, 0) == STALE) { |
| 1070 | D( fprintf(stderr, "noip: clearing away stale socket %s\n", |
| 1071 | d->d_name); ) |
| 1072 | unlink(sun.sun_path); |
| 1073 | } |
| 1074 | } |
| 1075 | closedir(dir); |
| 1076 | } |
| 1077 | |
| 1078 | /* Find the addresses attached to local network interfaces, and remember them |
| 1079 | * in a table. |
| 1080 | */ |
| 1081 | static void get_local_ipaddrs(void) |
| 1082 | { |
| 1083 | struct if_nameindex *ifn; |
| 1084 | struct ifreq ifr; |
| 1085 | int sk; |
| 1086 | int i; |
| 1087 | |
| 1088 | ifn = if_nameindex(); |
| 1089 | if ((sk = real_socket(PF_INET, SOCK_STREAM, 00)) < 0) |
| 1090 | return; |
| 1091 | for (i = n_local_ipaddrs = 0; |
| 1092 | n_local_ipaddrs < MAX_LOCAL_IPADDRS && |
| 1093 | ifn[i].if_name && *ifn[i].if_name; |
| 1094 | i++) { |
| 1095 | strcpy(ifr.ifr_name, ifn[i].if_name); |
| 1096 | if (ioctl(sk, SIOCGIFADDR, &ifr) || ifr.ifr_addr.sa_family != AF_INET) |
| 1097 | continue; |
| 1098 | local_ipaddrs[n_local_ipaddrs++] = |
| 1099 | SIN(&ifr.ifr_addr)->sin_addr; |
| 1100 | D( fprintf(stderr, "noip: local addr %s = %s\n", ifn[i].if_name, |
| 1101 | inet_ntoa(local_ipaddrs[n_local_ipaddrs - 1])); ) |
| 1102 | } |
| 1103 | close(sk); |
| 1104 | } |
| 1105 | |
| 1106 | /* Print the given message to standard error. Avoids stdio. */ |
| 1107 | static void printerr(const char *p) |
| 1108 | { int hunoz; hunoz = write(STDERR_FILENO, p, strlen(p)); } |
| 1109 | |
| 1110 | /* Create the socket directory, being careful about permissions. */ |
| 1111 | static void create_sockdir(void) |
| 1112 | { |
| 1113 | struct stat st; |
| 1114 | |
| 1115 | if (stat(sockdir, &st)) { |
| 1116 | if (errno == ENOENT) { |
| 1117 | if (mkdir(sockdir, 0700)) { |
| 1118 | perror("noip: creating socketdir"); |
| 1119 | exit(127); |
| 1120 | } |
| 1121 | if (!stat(sockdir, &st)) |
| 1122 | goto check; |
| 1123 | } |
| 1124 | perror("noip: checking socketdir"); |
| 1125 | exit(127); |
| 1126 | } |
| 1127 | check: |
| 1128 | if (!S_ISDIR(st.st_mode)) { |
| 1129 | printerr("noip: bad socketdir: not a directory\n"); |
| 1130 | exit(127); |
| 1131 | } |
| 1132 | if (st.st_uid != uid) { |
| 1133 | printerr("noip: bad socketdir: not owner\n"); |
| 1134 | exit(127); |
| 1135 | } |
| 1136 | if (st.st_mode & 077) { |
| 1137 | printerr("noip: bad socketdir: not private\n"); |
| 1138 | exit(127); |
| 1139 | } |
| 1140 | } |
| 1141 | |
| 1142 | /* Initialization function. */ |
| 1143 | static void setup(void) __attribute__((constructor)); |
| 1144 | static void setup(void) |
| 1145 | { |
| 1146 | PRESERVING_ERRNO({ |
| 1147 | char *p; |
| 1148 | |
| 1149 | import(); |
| 1150 | uid = geteuid(); |
| 1151 | if ((p = getenv("NOIP_DEBUG")) && atoi(p)) |
| 1152 | debug = 1; |
| 1153 | get_local_ipaddrs(); |
| 1154 | readconfig(); |
| 1155 | create_sockdir(); |
| 1156 | cleanup_sockdir(); |
| 1157 | }); |
| 1158 | } |
| 1159 | |
| 1160 | /*----- That's all, folks -------------------------------------------------*/ |