| 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 { DENY, ALLOW }; /* ACL verdicts */ |
| 64 | |
| 65 | static int address_families[] = { AF_INET, AF_INET6, -1 }; |
| 66 | |
| 67 | #define ADDRBUFSZ 64 |
| 68 | |
| 69 | /* Address representations. */ |
| 70 | typedef union ipaddr { |
| 71 | struct in_addr v4; |
| 72 | struct in6_addr v6; |
| 73 | } ipaddr; |
| 74 | |
| 75 | /* Convenient socket address hacking. */ |
| 76 | typedef union address { |
| 77 | struct sockaddr sa; |
| 78 | struct sockaddr_in sin; |
| 79 | struct sockaddr_in6 sin6; |
| 80 | } address; |
| 81 | |
| 82 | /* Access control list nodes */ |
| 83 | typedef struct aclnode { |
| 84 | struct aclnode *next; |
| 85 | int act; |
| 86 | int af; |
| 87 | ipaddr minaddr, maxaddr; |
| 88 | unsigned short minport, maxport; |
| 89 | } aclnode; |
| 90 | |
| 91 | /* Implicit bind records */ |
| 92 | typedef struct impbind { |
| 93 | struct impbind *next; |
| 94 | int af, how; |
| 95 | ipaddr minaddr, maxaddr, bindaddr; |
| 96 | } impbind; |
| 97 | enum { EXPLICIT, SAME }; |
| 98 | |
| 99 | /* A type for an address range */ |
| 100 | typedef struct addrrange { |
| 101 | int type; |
| 102 | union { |
| 103 | struct { int af; ipaddr min, max; } range; |
| 104 | } u; |
| 105 | } addrrange; |
| 106 | enum { EMPTY, ANY, LOCAL, RANGE }; |
| 107 | |
| 108 | /* Local address records */ |
| 109 | typedef struct full_ipaddr { |
| 110 | int af; |
| 111 | ipaddr addr; |
| 112 | } full_ipaddr; |
| 113 | #define MAX_LOCAL_IPADDRS 64 |
| 114 | static full_ipaddr local_ipaddrs[MAX_LOCAL_IPADDRS]; |
| 115 | static int n_local_ipaddrs; |
| 116 | |
| 117 | /* General configuration */ |
| 118 | static uid_t uid; |
| 119 | static char *sockdir = 0; |
| 120 | static int debug = 0; |
| 121 | static unsigned minautoport = 16384, maxautoport = 65536; |
| 122 | |
| 123 | /* Access control lists */ |
| 124 | static aclnode *bind_real, **bind_tail = &bind_real; |
| 125 | static aclnode *connect_real, **connect_tail = &connect_real; |
| 126 | static impbind *impbinds, **impbind_tail = &impbinds; |
| 127 | |
| 128 | /*----- Import the real versions of functions -----------------------------*/ |
| 129 | |
| 130 | /* The list of functions to immport. */ |
| 131 | #define IMPORTS(_) \ |
| 132 | _(socket, int, (int, int, int)) \ |
| 133 | _(socketpair, int, (int, int, int, int *)) \ |
| 134 | _(connect, int, (int, const struct sockaddr *, socklen_t)) \ |
| 135 | _(bind, int, (int, const struct sockaddr *, socklen_t)) \ |
| 136 | _(accept, int, (int, struct sockaddr *, socklen_t *)) \ |
| 137 | _(getsockname, int, (int, struct sockaddr *, socklen_t *)) \ |
| 138 | _(getpeername, int, (int, struct sockaddr *, socklen_t *)) \ |
| 139 | _(getsockopt, int, (int, int, int, void *, socklen_t *)) \ |
| 140 | _(setsockopt, int, (int, int, int, const void *, socklen_t)) \ |
| 141 | _(sendto, ssize_t, (int, const void *buf, size_t, int, \ |
| 142 | const struct sockaddr *to, socklen_t tolen)) \ |
| 143 | _(recvfrom, ssize_t, (int, void *buf, size_t, int, \ |
| 144 | struct sockaddr *from, socklen_t *fromlen)) \ |
| 145 | _(sendmsg, ssize_t, (int, const struct msghdr *, int)) \ |
| 146 | _(recvmsg, ssize_t, (int, struct msghdr *, int)) \ |
| 147 | _(ioctl, int, (int, unsigned long, ...)) |
| 148 | |
| 149 | /* Function pointers to set up. */ |
| 150 | #define DECL(imp, ret, args) static ret (*real_##imp) args; |
| 151 | IMPORTS(DECL) |
| 152 | #undef DECL |
| 153 | |
| 154 | /* Import the system calls. */ |
| 155 | static void import(void) |
| 156 | { |
| 157 | #define IMPORT(imp, ret, args) \ |
| 158 | real_##imp = (ret (*)args)dlsym(RTLD_NEXT, #imp); |
| 159 | IMPORTS(IMPORT) |
| 160 | #undef IMPORT |
| 161 | } |
| 162 | |
| 163 | /*----- Utilities ---------------------------------------------------------*/ |
| 164 | |
| 165 | /* Socket address casts */ |
| 166 | #define SA(sa) ((struct sockaddr *)(sa)) |
| 167 | #define SIN(sa) ((struct sockaddr_in *)(sa)) |
| 168 | #define SIN6(sa) ((struct sockaddr_in6 *)(sa)) |
| 169 | #define SUN(sa) ((struct sockaddr_un *)(sa)) |
| 170 | |
| 171 | /* Raw bytes */ |
| 172 | #define UC(ch) ((unsigned char)(ch)) |
| 173 | |
| 174 | /* Memory allocation */ |
| 175 | #define NEW(x) ((x) = xmalloc(sizeof(*x))) |
| 176 | #define NEWV(x, n) ((x) = xmalloc(sizeof(*x) * (n))) |
| 177 | |
| 178 | /* Debugging */ |
| 179 | #ifdef DEBUG |
| 180 | # define D(body) { if (debug) { body } } |
| 181 | # define Dpid pid_t pid = debug ? getpid() : -1 |
| 182 | #else |
| 183 | # define D(body) ; |
| 184 | # define Dpid |
| 185 | #endif |
| 186 | |
| 187 | /* Preservation of error status */ |
| 188 | #define PRESERVING_ERRNO(body) do { \ |
| 189 | int _err = errno; { body } errno = _err; \ |
| 190 | } while (0) |
| 191 | |
| 192 | /* Allocate N bytes of memory; abort on failure. */ |
| 193 | static void *xmalloc(size_t n) |
| 194 | { |
| 195 | void *p; |
| 196 | if (!n) return (0); |
| 197 | if ((p = malloc(n)) == 0) { perror("malloc"); exit(127); } |
| 198 | return (p); |
| 199 | } |
| 200 | |
| 201 | /* Allocate a copy of the null-terminated string P; abort on failure. */ |
| 202 | static char *xstrdup(const char *p) |
| 203 | { |
| 204 | size_t n = strlen(p) + 1; |
| 205 | char *q = xmalloc(n); |
| 206 | memcpy(q, p, n); |
| 207 | return (q); |
| 208 | } |
| 209 | |
| 210 | /*----- Address-type hacking ----------------------------------------------*/ |
| 211 | |
| 212 | /* If M is a simple mask, i.e., consists of a sequence of zero bits followed |
| 213 | * by a sequence of one bits, then return the length of the latter sequence |
| 214 | * (which may be zero); otherwise return -1. |
| 215 | */ |
| 216 | static int simple_mask_length(unsigned long m) |
| 217 | { |
| 218 | int n = 0; |
| 219 | |
| 220 | while (m & 1) { n++; m >>= 1; } |
| 221 | return (m ? -1 : n); |
| 222 | } |
| 223 | |
| 224 | /* Answer whether AF is an interesting address family. */ |
| 225 | static int family_known_p(int af) |
| 226 | { |
| 227 | switch (af) { |
| 228 | case AF_INET: |
| 229 | case AF_INET6: |
| 230 | return (1); |
| 231 | default: |
| 232 | return (0); |
| 233 | } |
| 234 | } |
| 235 | |
| 236 | /* Return the socket address length for address family AF. */ |
| 237 | static socklen_t family_socklen(int af) |
| 238 | { |
| 239 | switch (af) { |
| 240 | case AF_INET: return (sizeof(struct sockaddr_in)); |
| 241 | case AF_INET6: return (sizeof(struct sockaddr_in6)); |
| 242 | default: abort(); |
| 243 | } |
| 244 | } |
| 245 | |
| 246 | /* Return the width of addresses of kind AF. */ |
| 247 | static int address_width(int af) |
| 248 | { |
| 249 | switch (af) { |
| 250 | case AF_INET: return 32; |
| 251 | case AF_INET6: return 128; |
| 252 | default: abort(); |
| 253 | } |
| 254 | } |
| 255 | |
| 256 | /* If addresses A and B share a common prefix then return its length; |
| 257 | * otherwise return -1. |
| 258 | */ |
| 259 | static int common_prefix_length(int af, const ipaddr *a, const ipaddr *b) |
| 260 | { |
| 261 | switch (af) { |
| 262 | case AF_INET: { |
| 263 | unsigned long aa = ntohl(a->v4.s_addr), bb = ntohl(b->v4.s_addr); |
| 264 | unsigned long m = aa^bb; |
| 265 | if ((aa&m) == 0 && (bb&m) == m) return (32 - simple_mask_length(m)); |
| 266 | else return (-1); |
| 267 | } break; |
| 268 | case AF_INET6: { |
| 269 | const uint8_t *aa = a->v6.s6_addr, *bb = b->v6.s6_addr; |
| 270 | unsigned m; |
| 271 | unsigned n; |
| 272 | int i; |
| 273 | |
| 274 | for (i = 0; i < 16 && aa[i] == bb[i]; i++); |
| 275 | n = 8*i; |
| 276 | if (i < 16) { |
| 277 | m = aa[i]^bb[i]; |
| 278 | if ((aa[i]&m) != 0 || (bb[i]&m) != m) return (-1); |
| 279 | n += 8 - simple_mask_length(m); |
| 280 | for (i++; i < 16; i++) |
| 281 | if (aa[i] || bb[i] != 0xff) return (-1); |
| 282 | } |
| 283 | return (n); |
| 284 | } break; |
| 285 | default: |
| 286 | abort(); |
| 287 | } |
| 288 | } |
| 289 | |
| 290 | /* Extract the port number (in host byte-order) from SA. */ |
| 291 | static int port_from_sockaddr(const struct sockaddr *sa) |
| 292 | { |
| 293 | switch (sa->sa_family) { |
| 294 | case AF_INET: return (ntohs(SIN(sa)->sin_port)); |
| 295 | case AF_INET6: return (ntohs(SIN6(sa)->sin6_port)); |
| 296 | default: abort(); |
| 297 | } |
| 298 | } |
| 299 | |
| 300 | /* Store the port number PORT (in host byte-order) in SA. */ |
| 301 | static void port_to_sockaddr(struct sockaddr *sa, int port) |
| 302 | { |
| 303 | switch (sa->sa_family) { |
| 304 | case AF_INET: SIN(sa)->sin_port = htons(port); break; |
| 305 | case AF_INET6: SIN6(sa)->sin6_port = htons(port); break; |
| 306 | default: abort(); |
| 307 | } |
| 308 | } |
| 309 | |
| 310 | /* Extract the address part from SA and store it in A. */ |
| 311 | static void ipaddr_from_sockaddr(ipaddr *a, const struct sockaddr *sa) |
| 312 | { |
| 313 | switch (sa->sa_family) { |
| 314 | case AF_INET: a->v4 = SIN(sa)->sin_addr; break; |
| 315 | case AF_INET6: a->v6 = SIN6(sa)->sin6_addr; break; |
| 316 | default: abort(); |
| 317 | } |
| 318 | } |
| 319 | |
| 320 | /* Store the address A in SA. */ |
| 321 | static void ipaddr_to_sockaddr(struct sockaddr *sa, const ipaddr *a) |
| 322 | { |
| 323 | switch (sa->sa_family) { |
| 324 | case AF_INET: |
| 325 | SIN(sa)->sin_addr = a->v4; |
| 326 | break; |
| 327 | case AF_INET6: |
| 328 | SIN6(sa)->sin6_addr = a->v6; |
| 329 | SIN6(sa)->sin6_scope_id = 0; |
| 330 | SIN6(sa)->sin6_flowinfo = 0; |
| 331 | break; |
| 332 | default: |
| 333 | abort(); |
| 334 | } |
| 335 | } |
| 336 | |
| 337 | /* Copy a whole socket address about. */ |
| 338 | static void copy_sockaddr(struct sockaddr *sa_dst, |
| 339 | const struct sockaddr *sa_src) |
| 340 | { memcpy(sa_dst, sa_src, family_socklen(sa_src->sa_family)); } |
| 341 | |
| 342 | /* Answer whether two addresses are equal. */ |
| 343 | static int ipaddr_equal_p(int af, const ipaddr *a, const ipaddr *b) |
| 344 | { |
| 345 | switch (af) { |
| 346 | case AF_INET: return (a->v4.s_addr == b->v4.s_addr); |
| 347 | case AF_INET6: return (memcmp(a->v6.s6_addr, b->v6.s6_addr, 16) == 0); |
| 348 | default: abort(); |
| 349 | } |
| 350 | } |
| 351 | |
| 352 | /* Answer whether the address part of SA is between A and B (inclusive). We |
| 353 | * assume that SA has the correct address family. |
| 354 | */ |
| 355 | static int sockaddr_in_range_p(const struct sockaddr *sa, |
| 356 | const ipaddr *a, const ipaddr *b) |
| 357 | { |
| 358 | switch (sa->sa_family) { |
| 359 | case AF_INET: { |
| 360 | unsigned long addr = ntohl(SIN(sa)->sin_addr.s_addr); |
| 361 | return (ntohl(a->v4.s_addr) <= addr && |
| 362 | addr <= ntohl(b->v4.s_addr)); |
| 363 | } break; |
| 364 | case AF_INET6: { |
| 365 | const uint8_t *ss = SIN6(sa)->sin6_addr.s6_addr; |
| 366 | const uint8_t *aa = a->v6.s6_addr, *bb = b->v6.s6_addr; |
| 367 | int h = 1, l = 1; |
| 368 | int i; |
| 369 | |
| 370 | for (i = 0; h && l && i < 16; i++, ss++, aa++, bb++) { |
| 371 | if (*ss < *aa || *bb < *ss) return (0); |
| 372 | if (*aa < *ss) l = 0; |
| 373 | if (*ss < *bb) h = 0; |
| 374 | } |
| 375 | return (1); |
| 376 | } break; |
| 377 | default: |
| 378 | abort(); |
| 379 | } |
| 380 | } |
| 381 | |
| 382 | /* Fill in SA with the appropriate wildcard address. */ |
| 383 | static void wildcard_address(int af, struct sockaddr *sa) |
| 384 | { |
| 385 | switch (af) { |
| 386 | case AF_INET: { |
| 387 | struct sockaddr_in *sin = SIN(sa); |
| 388 | memset(sin, 0, sizeof(*sin)); |
| 389 | sin->sin_family = AF_INET; |
| 390 | sin->sin_port = 0; |
| 391 | sin->sin_addr.s_addr = INADDR_ANY; |
| 392 | } break; |
| 393 | case AF_INET6: { |
| 394 | struct sockaddr_in6 *sin6 = SIN6(sa); |
| 395 | memset(sin6, 0, sizeof(*sin6)); |
| 396 | sin6->sin6_family = AF_INET6; |
| 397 | sin6->sin6_port = 0; |
| 398 | sin6->sin6_addr = in6addr_any; |
| 399 | sin6->sin6_scope_id = 0; |
| 400 | sin6->sin6_flowinfo = 0; |
| 401 | } break; |
| 402 | default: |
| 403 | abort(); |
| 404 | } |
| 405 | } |
| 406 | |
| 407 | /* Mask the address A, forcing all but the top PLEN bits to zero or one |
| 408 | * according to HIGHP. |
| 409 | */ |
| 410 | static void mask_address(int af, ipaddr *a, int plen, int highp) |
| 411 | { |
| 412 | switch (af) { |
| 413 | case AF_INET: { |
| 414 | unsigned long addr = ntohl(a->v4.s_addr); |
| 415 | unsigned long mask = plen ? ~0ul << (32 - plen) : 0; |
| 416 | addr &= mask; |
| 417 | if (highp) addr |= ~mask; |
| 418 | a->v4.s_addr = htonl(addr & 0xffffffff); |
| 419 | } break; |
| 420 | case AF_INET6: { |
| 421 | int i = plen/8; |
| 422 | unsigned m = (0xff << (8 - plen%8)) & 0xff; |
| 423 | unsigned s = highp ? 0xff : 0; |
| 424 | if (m) { |
| 425 | a->v6.s6_addr[i] = (a->v6.s6_addr[i] & m) | (s & ~m); |
| 426 | i++; |
| 427 | } |
| 428 | for (; i < 16; i++) a->v6.s6_addr[i] = s; |
| 429 | } break; |
| 430 | default: |
| 431 | abort(); |
| 432 | } |
| 433 | } |
| 434 | |
| 435 | /* Write a presentation form of SA to BUF, a buffer of length SZ. LEN is the |
| 436 | * address length; if it's zero, look it up based on the address family. |
| 437 | * Return a pointer to the string (which might, in an emergency, be a static |
| 438 | * string rather than your buffer). |
| 439 | */ |
| 440 | static char *present_sockaddr(const struct sockaddr *sa, socklen_t len, |
| 441 | char *buf, size_t sz) |
| 442 | { |
| 443 | #define WANT(n_) do { if (sz < (n_)) goto nospace; } while (0) |
| 444 | #define PUTC(c_) do { *buf++ = (c_); sz--; } while (0) |
| 445 | |
| 446 | if (!sa) return "<null-address>"; |
| 447 | if (!sz) return "<no-space-in-buffer>"; |
| 448 | if (!len) len = family_socklen(sa->sa_family); |
| 449 | |
| 450 | switch (sa->sa_family) { |
| 451 | case AF_UNIX: { |
| 452 | struct sockaddr_un *sun = SUN(sa); |
| 453 | char *p = sun->sun_path; |
| 454 | size_t n = len - offsetof(struct sockaddr_un, sun_path); |
| 455 | |
| 456 | assert(n); |
| 457 | if (*p == 0) { |
| 458 | WANT(1); PUTC('@'); |
| 459 | p++; n--; |
| 460 | while (n) { |
| 461 | switch (*p) { |
| 462 | case 0: WANT(2); PUTC('\\'); PUTC('0'); break; |
| 463 | case '\a': WANT(2); PUTC('\\'); PUTC('a'); break; |
| 464 | case '\n': WANT(2); PUTC('\\'); PUTC('n'); break; |
| 465 | case '\r': WANT(2); PUTC('\\'); PUTC('r'); break; |
| 466 | case '\t': WANT(2); PUTC('\\'); PUTC('t'); break; |
| 467 | case '\v': WANT(2); PUTC('\\'); PUTC('v'); break; |
| 468 | case '\\': WANT(2); PUTC('\\'); PUTC('\\'); break; |
| 469 | default: |
| 470 | if (*p > ' ' && *p <= '~') |
| 471 | { WANT(1); PUTC(*p); } |
| 472 | else { |
| 473 | WANT(4); PUTC('\\'); PUTC('x'); |
| 474 | PUTC((*p >> 4)&0xf); PUTC((*p >> 0)&0xf); |
| 475 | } |
| 476 | break; |
| 477 | } |
| 478 | p++; n--; |
| 479 | } |
| 480 | } else { |
| 481 | if (*p != '/') { WANT(2); PUTC('.'); PUTC('/'); } |
| 482 | while (n && *p) { WANT(1); PUTC(*p); p++; n--; } |
| 483 | } |
| 484 | WANT(1); PUTC(0); |
| 485 | } break; |
| 486 | case AF_INET: case AF_INET6: { |
| 487 | char addrbuf[NI_MAXHOST], portbuf[NI_MAXSERV]; |
| 488 | int err = getnameinfo(sa, len, |
| 489 | addrbuf, sizeof(addrbuf), |
| 490 | portbuf, sizeof(portbuf), |
| 491 | NI_NUMERICHOST | NI_NUMERICSERV); |
| 492 | assert(!err); |
| 493 | snprintf(buf, sz, strchr(addrbuf, ':') ? "[%s]:%s" : "%s:%s", |
| 494 | addrbuf, portbuf); |
| 495 | } break; |
| 496 | default: |
| 497 | snprintf(buf, sz, "<unknown-address-family %d>", sa->sa_family); |
| 498 | break; |
| 499 | } |
| 500 | return (buf); |
| 501 | |
| 502 | nospace: |
| 503 | buf[sz - 1] = 0; |
| 504 | return (buf); |
| 505 | } |
| 506 | |
| 507 | /* Guess the family of a textual socket address. */ |
| 508 | static int guess_address_family(const char *p) |
| 509 | { return (strchr(p, ':') ? AF_INET6 : AF_INET); } |
| 510 | |
| 511 | /* Parse a socket address P and write the result to SA. */ |
| 512 | static int parse_sockaddr(struct sockaddr *sa, const char *p) |
| 513 | { |
| 514 | char buf[ADDRBUFSZ]; |
| 515 | char *q; |
| 516 | struct addrinfo *ai, ai_hint = { 0 }; |
| 517 | |
| 518 | if (strlen(p) >= sizeof(buf) - 1) return (-1); |
| 519 | strcpy(buf, p); p = buf; |
| 520 | if (*p != '[') { |
| 521 | if ((q = strchr(p, ':')) == 0) return (-1); |
| 522 | *q++ = 0; |
| 523 | } else { |
| 524 | p++; |
| 525 | if ((q = strchr(p, ']')) == 0) return (-1); |
| 526 | *q++ = 0; |
| 527 | if (*q != ':') return (-1); |
| 528 | q++; |
| 529 | } |
| 530 | |
| 531 | ai_hint.ai_family = AF_UNSPEC; |
| 532 | ai_hint.ai_socktype = SOCK_DGRAM; |
| 533 | ai_hint.ai_flags = AI_NUMERICHOST | AI_NUMERICSERV; |
| 534 | if (getaddrinfo(p, q, &ai_hint, &ai)) return (-1); |
| 535 | memcpy(sa, ai->ai_addr, ai->ai_addrlen); |
| 536 | freeaddrinfo(ai); |
| 537 | return (0); |
| 538 | } |
| 539 | |
| 540 | /*----- Access control lists ----------------------------------------------*/ |
| 541 | |
| 542 | #ifdef DEBUG |
| 543 | |
| 544 | static void dump_addrrange(int af, const ipaddr *min, const ipaddr *max) |
| 545 | { |
| 546 | char buf[ADDRBUFSZ]; |
| 547 | const char *p; |
| 548 | int plen; |
| 549 | |
| 550 | plen = common_prefix_length(af, min, max); |
| 551 | p = inet_ntop(af, min, buf, sizeof(buf)); |
| 552 | fprintf(stderr, strchr(p, ':') ? "[%s]" : "%s", p); |
| 553 | if (plen < 0) { |
| 554 | p = inet_ntop(af, &max, buf, sizeof(buf)); |
| 555 | fprintf(stderr, strchr(p, ':') ? "-[%s]" : "-%s", p); |
| 556 | } else if (plen < address_width(af)) |
| 557 | fprintf(stderr, "/%d", plen); |
| 558 | } |
| 559 | |
| 560 | /* Write to standard error a description of the ACL node A. */ |
| 561 | static void dump_aclnode(const aclnode *a) |
| 562 | { |
| 563 | fprintf(stderr, "noip(%d): %c ", getpid(), a->act ? '+' : '-'); |
| 564 | dump_addrrange(a->af, &a->minaddr, &a->maxaddr); |
| 565 | if (a->minport != 0 || a->maxport != 0xffff) { |
| 566 | fprintf(stderr, ":%u", (unsigned)a->minport); |
| 567 | if (a->minport != a->maxport) |
| 568 | fprintf(stderr, "-%u", (unsigned)a->maxport); |
| 569 | } |
| 570 | fputc('\n', stderr); |
| 571 | } |
| 572 | |
| 573 | static void dump_acl(const aclnode *a) |
| 574 | { |
| 575 | int act = ALLOW; |
| 576 | |
| 577 | for (; a; a = a->next) { |
| 578 | dump_aclnode(a); |
| 579 | act = a->act; |
| 580 | } |
| 581 | fprintf(stderr, "noip(%d): [default policy: %s]\n", getpid(), |
| 582 | act == ALLOW ? "DENY" : "ALLOW"); |
| 583 | } |
| 584 | |
| 585 | #endif |
| 586 | |
| 587 | /* Returns nonzero if the ACL A allows the socket address SA. */ |
| 588 | static int acl_allows_p(const aclnode *a, const struct sockaddr *sa) |
| 589 | { |
| 590 | unsigned short port = port_from_sockaddr(sa); |
| 591 | int act = ALLOW; |
| 592 | Dpid; |
| 593 | |
| 594 | D({ char buf[ADDRBUFSZ]; |
| 595 | fprintf(stderr, "noip(%d): check %s\n", pid, |
| 596 | present_sockaddr(sa, 0, buf, sizeof(buf))); }) |
| 597 | for (; a; a = a->next) { |
| 598 | D( dump_aclnode(a); ) |
| 599 | if (a->af == sa->sa_family && |
| 600 | sockaddr_in_range_p(sa, &a->minaddr, &a->maxaddr) && |
| 601 | a->minport <= port && port <= a->maxport) { |
| 602 | D( fprintf(stderr, "noip(%d): aha! %s\n", pid, |
| 603 | a->act ? "ALLOW" : "DENY"); ) |
| 604 | return (a->act); |
| 605 | } |
| 606 | act = a->act; |
| 607 | } |
| 608 | D( fprintf(stderr, "noip(%d): nothing found: %s\n", pid, |
| 609 | act ? "DENY" : "ALLOW"); ) |
| 610 | return (!act); |
| 611 | } |
| 612 | |
| 613 | /*----- Socket address conversion -----------------------------------------*/ |
| 614 | |
| 615 | /* Return a uniformly distributed integer between MIN and MAX inclusive. */ |
| 616 | static unsigned randrange(unsigned min, unsigned max) |
| 617 | { |
| 618 | unsigned mask, i; |
| 619 | |
| 620 | /* It's so nice not to have to care about the quality of the generator |
| 621 | * much! |
| 622 | */ |
| 623 | max -= min; |
| 624 | for (mask = 1; mask < max; mask = (mask << 1) | 1) |
| 625 | ; |
| 626 | do i = rand() & mask; while (i > max); |
| 627 | return (i + min); |
| 628 | } |
| 629 | |
| 630 | /* Return the status of Unix-domain socket address SUN. Returns: UNUSED if |
| 631 | * the socket doesn't exist; USED if the path refers to an active socket, or |
| 632 | * isn't really a socket at all, or we can't tell without a careful search |
| 633 | * and QUICKP is set; or STALE if the file refers to a socket which isn't |
| 634 | * being used any more. |
| 635 | */ |
| 636 | static int unix_socket_status(struct sockaddr_un *sun, int quickp) |
| 637 | { |
| 638 | struct stat st; |
| 639 | FILE *fp = 0; |
| 640 | size_t len, n; |
| 641 | int rc; |
| 642 | char buf[256]; |
| 643 | |
| 644 | if (stat(sun->sun_path, &st)) |
| 645 | return (errno == ENOENT ? UNUSED : USED); |
| 646 | if (!S_ISSOCK(st.st_mode) || quickp) |
| 647 | return (USED); |
| 648 | rc = USED; |
| 649 | if ((fp = fopen("/proc/net/unix", "r")) == 0) |
| 650 | goto done; |
| 651 | if (!fgets(buf, sizeof(buf), fp)) goto done; /* skip header */ |
| 652 | len = strlen(sun->sun_path); |
| 653 | while (fgets(buf, sizeof(buf), fp)) { |
| 654 | n = strlen(buf); |
| 655 | if (n >= len + 2 && buf[n - len - 2] == ' ' && buf[n - 1] == '\n' && |
| 656 | memcmp(buf + n - len - 1, sun->sun_path, len) == 0) |
| 657 | goto done; |
| 658 | } |
| 659 | if (ferror(fp)) |
| 660 | goto done; |
| 661 | rc = STALE; |
| 662 | done: |
| 663 | if (fp) fclose(fp); |
| 664 | return (rc); |
| 665 | } |
| 666 | |
| 667 | /* Convert the IP address SA to a Unix-domain address SUN. Fail if the |
| 668 | * address seems already taken. If DESPARATEP then try cleaning up stale old |
| 669 | * sockets. |
| 670 | */ |
| 671 | static int encode_unused_inet_addr(struct sockaddr *sa, |
| 672 | struct sockaddr_un *sun, |
| 673 | int desperatep) |
| 674 | { |
| 675 | address waddr; |
| 676 | struct sockaddr_un wsun; |
| 677 | int rc; |
| 678 | char buf[ADDRBUFSZ]; |
| 679 | int port = port_from_sockaddr(sa); |
| 680 | |
| 681 | snprintf(sun->sun_path, sizeof(sun->sun_path), "%s/%s", sockdir, |
| 682 | present_sockaddr(sa, 0, buf, sizeof(buf))); |
| 683 | if ((rc = unix_socket_status(sun, !desperatep)) == USED) return (-1); |
| 684 | else if (rc == STALE) unlink(sun->sun_path); |
| 685 | |
| 686 | wildcard_address(sa->sa_family, &waddr.sa); |
| 687 | port_to_sockaddr(&waddr.sa, port); |
| 688 | snprintf(wsun.sun_path, sizeof(wsun.sun_path), "%s/%s", sockdir, |
| 689 | present_sockaddr(&waddr.sa, 0, buf, sizeof(buf))); |
| 690 | if ((rc = unix_socket_status(&wsun, !desperatep)) == USED) return (-1); |
| 691 | else if (rc == STALE) unlink(wsun.sun_path); |
| 692 | |
| 693 | return (0); |
| 694 | } |
| 695 | |
| 696 | /* Encode the Internet address SA as a Unix-domain address SUN. If the flag |
| 697 | * `ENCF_FRESH' is set, and SA's port number is zero, then we pick an |
| 698 | * arbitrary local port. Otherwise we pick the port given. There's an |
| 699 | * unpleasant hack to find servers bound to local wildcard addresses. |
| 700 | * Returns zero on success; -1 on failure. |
| 701 | */ |
| 702 | #define ENCF_FRESH 1u |
| 703 | static int encode_inet_addr(struct sockaddr_un *sun, |
| 704 | const struct sockaddr *sa, |
| 705 | unsigned f) |
| 706 | { |
| 707 | int i; |
| 708 | int desperatep = 0; |
| 709 | address addr; |
| 710 | int port = port_from_sockaddr(sa); |
| 711 | char buf[ADDRBUFSZ]; |
| 712 | int rc; |
| 713 | |
| 714 | D( fprintf(stderr, "noip(%d): encode %s (%s)", getpid(), |
| 715 | present_sockaddr(sa, 0, buf, sizeof(buf)), |
| 716 | (f&ENCF_FRESH) ? "FRESH" : "EXISTING"); ) |
| 717 | sun->sun_family = AF_UNIX; |
| 718 | if (port || !(f&ENCF_FRESH)) { |
| 719 | snprintf(sun->sun_path, sizeof(sun->sun_path), "%s/%s", sockdir, |
| 720 | present_sockaddr(sa, 0, buf, sizeof(buf))); |
| 721 | rc = unix_socket_status(sun, 0); |
| 722 | if (rc == STALE) unlink(sun->sun_path); |
| 723 | if (rc != USED && !(f&ENCF_FRESH)) { |
| 724 | wildcard_address(sa->sa_family, &addr.sa); |
| 725 | port_to_sockaddr(&addr.sa, port); |
| 726 | snprintf(sun->sun_path, sizeof(sun->sun_path), "%s/%s", sockdir, |
| 727 | present_sockaddr(&addr.sa, 0, buf, sizeof(buf))); |
| 728 | if (unix_socket_status(sun, 0) == STALE) unlink(sun->sun_path); |
| 729 | } |
| 730 | } else { |
| 731 | copy_sockaddr(&addr.sa, sa); |
| 732 | for (i = 0; i < 10; i++) { |
| 733 | port_to_sockaddr(&addr.sa, randrange(minautoport, maxautoport)); |
| 734 | if (!encode_unused_inet_addr(&addr.sa, sun, 0)) goto found; |
| 735 | } |
| 736 | for (desperatep = 0; desperatep < 2; desperatep++) { |
| 737 | for (i = minautoport; i <= maxautoport; i++) { |
| 738 | port_to_sockaddr(&addr.sa, i); |
| 739 | if (!encode_unused_inet_addr(&addr.sa, sun, 0)) goto found; |
| 740 | } |
| 741 | } |
| 742 | errno = EADDRINUSE; |
| 743 | D( fprintf(stderr, " -- can't resolve\n"); ) |
| 744 | return (-1); |
| 745 | } |
| 746 | found: |
| 747 | D( fprintf(stderr, " -> `%s'\n", sun->sun_path); ) |
| 748 | return (0); |
| 749 | } |
| 750 | |
| 751 | /* Decode the Unix address SUN to an Internet address SIN. If AF_HINT is |
| 752 | * nonzero, an empty address (indicative of an unbound Unix-domain socket) is |
| 753 | * translated to a wildcard Internet address of the appropriate family. |
| 754 | * Returns zero on success; -1 on failure (e.g., it wasn't one of our |
| 755 | * addresses). |
| 756 | */ |
| 757 | static int decode_inet_addr(struct sockaddr *sa, int af_hint, |
| 758 | const struct sockaddr_un *sun, |
| 759 | socklen_t len) |
| 760 | { |
| 761 | char buf[ADDRBUFSZ]; |
| 762 | size_t n = strlen(sockdir), nn; |
| 763 | address addr; |
| 764 | |
| 765 | if (!sa) sa = &addr.sa; |
| 766 | if (sun->sun_family != AF_UNIX) return (-1); |
| 767 | if (len > sizeof(*sun)) return (-1); |
| 768 | ((char *)sun)[len] = 0; |
| 769 | nn = strlen(sun->sun_path); |
| 770 | D( fprintf(stderr, "noip(%d): decode `%s'", getpid(), sun->sun_path); ) |
| 771 | if (af_hint && !sun->sun_path[0]) { |
| 772 | wildcard_address(af_hint, sa); |
| 773 | D( fprintf(stderr, " -- unbound socket\n"); ) |
| 774 | return (0); |
| 775 | } |
| 776 | if (nn < n + 1 || nn - n >= sizeof(buf) || sun->sun_path[n] != '/' || |
| 777 | memcmp(sun->sun_path, sockdir, n) != 0) { |
| 778 | D( fprintf(stderr, " -- not one of ours\n"); ) |
| 779 | return (-1); |
| 780 | } |
| 781 | if (parse_sockaddr(sa, sun->sun_path + n + 1)) return (-1); |
| 782 | D( fprintf(stderr, " -> %s\n", |
| 783 | present_sockaddr(sa, 0, buf, sizeof(buf))); ) |
| 784 | return (0); |
| 785 | } |
| 786 | |
| 787 | /* SK is (or at least might be) a Unix-domain socket we created when an |
| 788 | * Internet socket was asked for. We've decided it should be an Internet |
| 789 | * socket after all, with family AF_HINT, so convert it. If TMP is not null, |
| 790 | * then don't replace the existing descriptor: store the new socket in *TMP |
| 791 | * and return zero. |
| 792 | */ |
| 793 | static int fixup_real_ip_socket(int sk, int af_hint, int *tmp) |
| 794 | { |
| 795 | int nsk; |
| 796 | int type; |
| 797 | int f, fd; |
| 798 | struct sockaddr_un sun; |
| 799 | address addr; |
| 800 | socklen_t len; |
| 801 | |
| 802 | #define OPTS(_) \ |
| 803 | _(DEBUG, int) \ |
| 804 | _(REUSEADDR, int) \ |
| 805 | _(DONTROUTE, int) \ |
| 806 | _(BROADCAST, int) \ |
| 807 | _(SNDBUF, int) \ |
| 808 | _(RCVBUF, int) \ |
| 809 | _(OOBINLINE, int) \ |
| 810 | _(NO_CHECK, int) \ |
| 811 | _(LINGER, struct linger) \ |
| 812 | _(BSDCOMPAT, int) \ |
| 813 | _(RCVLOWAT, int) \ |
| 814 | _(RCVTIMEO, struct timeval) \ |
| 815 | _(SNDTIMEO, struct timeval) |
| 816 | |
| 817 | len = sizeof(sun); |
| 818 | if (real_getsockname(sk, SA(&sun), &len)) |
| 819 | return (-1); |
| 820 | if (decode_inet_addr(&addr.sa, af_hint, &sun, len)) |
| 821 | return (0); /* Not one of ours */ |
| 822 | len = sizeof(type); |
| 823 | if (real_getsockopt(sk, SOL_SOCKET, SO_TYPE, &type, &len) < 0 || |
| 824 | (nsk = real_socket(addr.sa.sa_family, type, 0)) < 0) |
| 825 | return (-1); |
| 826 | #define FIX(opt, ty) do { \ |
| 827 | ty ov_; \ |
| 828 | len = sizeof(ov_); \ |
| 829 | if (real_getsockopt(sk, SOL_SOCKET, SO_##opt, &ov_, &len) < 0 || \ |
| 830 | real_setsockopt(nsk, SOL_SOCKET, SO_##opt, &ov_, len)) { \ |
| 831 | close(nsk); \ |
| 832 | return (-1); \ |
| 833 | } \ |
| 834 | } while (0); |
| 835 | OPTS(FIX) |
| 836 | #undef FIX |
| 837 | if (tmp) |
| 838 | *tmp = nsk; |
| 839 | else { |
| 840 | if ((f = fcntl(sk, F_GETFL)) < 0 || |
| 841 | (fd = fcntl(sk, F_GETFD)) < 0 || |
| 842 | fcntl(nsk, F_SETFL, f) < 0 || |
| 843 | dup2(nsk, sk) < 0) { |
| 844 | close(nsk); |
| 845 | return (-1); |
| 846 | } |
| 847 | unlink(sun.sun_path); |
| 848 | close(nsk); |
| 849 | if (fcntl(sk, F_SETFD, fd) < 0) { |
| 850 | perror("noip: fixup_real_ip_socket F_SETFD"); |
| 851 | abort(); |
| 852 | } |
| 853 | } |
| 854 | return (0); |
| 855 | } |
| 856 | |
| 857 | /* We found the real address SA, with length LEN; if it's a Unix-domain |
| 858 | * address corresponding to a fake socket, convert it to cover up the |
| 859 | * deception. Whatever happens, put the result at FAKE and store its length |
| 860 | * at FAKELEN. |
| 861 | */ |
| 862 | static void return_fake_name(struct sockaddr *sa, socklen_t len, |
| 863 | struct sockaddr *fake, socklen_t *fakelen) |
| 864 | { |
| 865 | address addr; |
| 866 | socklen_t alen; |
| 867 | |
| 868 | if (sa->sa_family == AF_UNIX && |
| 869 | !decode_inet_addr(&addr.sa, 0, SUN(sa), len)) { |
| 870 | sa = &addr.sa; |
| 871 | len = family_socklen(addr.sa.sa_family); |
| 872 | } |
| 873 | alen = len; |
| 874 | if (len > *fakelen) len = *fakelen; |
| 875 | if (len > 0) memcpy(fake, sa, len); |
| 876 | *fakelen = alen; |
| 877 | } |
| 878 | |
| 879 | /*----- Implicit binding --------------------------------------------------*/ |
| 880 | |
| 881 | #ifdef DEBUG |
| 882 | |
| 883 | static void dump_impbind(const impbind *i) |
| 884 | { |
| 885 | char buf[ADDRBUFSZ]; |
| 886 | |
| 887 | fprintf(stderr, "noip(%d): ", getpid()); |
| 888 | dump_addrrange(i->af, &i->minaddr, &i->maxaddr); |
| 889 | switch (i->how) { |
| 890 | case SAME: fprintf(stderr, " <self>"); break; |
| 891 | case EXPLICIT: |
| 892 | fprintf(stderr, " %s", inet_ntop(i->af, &i->bindaddr, |
| 893 | buf, sizeof(buf))); |
| 894 | break; |
| 895 | default: abort(); |
| 896 | } |
| 897 | fputc('\n', stderr); |
| 898 | } |
| 899 | |
| 900 | static void dump_impbind_list(void) |
| 901 | { |
| 902 | const impbind *i; |
| 903 | |
| 904 | for (i = impbinds; i; i = i->next) dump_impbind(i); |
| 905 | } |
| 906 | |
| 907 | #endif |
| 908 | |
| 909 | /* The socket SK is about to be used to communicate with the remote address |
| 910 | * SA. Assign it a local address so that getpeername(2) does something |
| 911 | * useful. |
| 912 | */ |
| 913 | static int do_implicit_bind(int sk, const struct sockaddr **sa, |
| 914 | socklen_t *len, struct sockaddr_un *sun) |
| 915 | { |
| 916 | address addr; |
| 917 | socklen_t mylen = sizeof(*sun); |
| 918 | const impbind *i; |
| 919 | Dpid; |
| 920 | |
| 921 | if (acl_allows_p(connect_real, *sa)) { |
| 922 | if (fixup_real_ip_socket(sk, (*sa)->sa_family, 0)) return (-1); |
| 923 | } else { |
| 924 | if (real_getsockname(sk, SA(sun), &mylen) < 0) return (-1); |
| 925 | if (sun->sun_family == AF_UNIX) { |
| 926 | if (mylen < sizeof(*sun)) ((char *)sun)[mylen] = 0; |
| 927 | if (!sun->sun_path[0]) { |
| 928 | D( fprintf(stderr, "noip(%d): checking impbind list...\n", pid); ) |
| 929 | for (i = impbinds; i; i = i->next) { |
| 930 | D( dump_impbind(i); ) |
| 931 | if ((*sa)->sa_family == i->af && |
| 932 | sockaddr_in_range_p(*sa, &i->minaddr, &i->maxaddr)) { |
| 933 | D( fprintf(stderr, "noip(%d): match!\n", pid); ) |
| 934 | addr.sa.sa_family = (*sa)->sa_family; |
| 935 | ipaddr_to_sockaddr(&addr.sa, &i->bindaddr); |
| 936 | goto found; |
| 937 | } |
| 938 | } |
| 939 | D( fprintf(stderr, "noip(%d): no match; using wildcard\n", pid); ) |
| 940 | wildcard_address((*sa)->sa_family, &addr.sa); |
| 941 | found: |
| 942 | encode_inet_addr(sun, &addr.sa, ENCF_FRESH); |
| 943 | if (real_bind(sk, SA(sun), SUN_LEN(sun))) return (-1); |
| 944 | } |
| 945 | encode_inet_addr(sun, *sa, 0); |
| 946 | *sa = SA(sun); |
| 947 | *len = SUN_LEN(sun); |
| 948 | } |
| 949 | } |
| 950 | return (0); |
| 951 | } |
| 952 | |
| 953 | /*----- Configuration -----------------------------------------------------*/ |
| 954 | |
| 955 | /* Return the process owner's home directory. */ |
| 956 | static char *home(void) |
| 957 | { |
| 958 | char *p; |
| 959 | struct passwd *pw; |
| 960 | |
| 961 | if (getuid() == uid && |
| 962 | (p = getenv("HOME")) != 0) |
| 963 | return (p); |
| 964 | else if ((pw = getpwuid(uid)) != 0) |
| 965 | return (pw->pw_dir); |
| 966 | else |
| 967 | return "/notexist"; |
| 968 | } |
| 969 | |
| 970 | /* Return a good temporary directory to use. */ |
| 971 | static char *tmpdir(void) |
| 972 | { |
| 973 | char *p; |
| 974 | |
| 975 | if ((p = getenv("TMPDIR")) != 0) return (p); |
| 976 | else if ((p = getenv("TMP")) != 0) return (p); |
| 977 | else return ("/tmp"); |
| 978 | } |
| 979 | |
| 980 | /* Return the user's name, or at least something distinctive. */ |
| 981 | static char *user(void) |
| 982 | { |
| 983 | static char buf[16]; |
| 984 | char *p; |
| 985 | struct passwd *pw; |
| 986 | |
| 987 | if ((p = getenv("USER")) != 0) return (p); |
| 988 | else if ((p = getenv("LOGNAME")) != 0) return (p); |
| 989 | else if ((pw = getpwuid(uid)) != 0) return (pw->pw_name); |
| 990 | else { |
| 991 | snprintf(buf, sizeof(buf), "uid-%lu", (unsigned long)uid); |
| 992 | return (buf); |
| 993 | } |
| 994 | } |
| 995 | |
| 996 | /* Skip P over space characters. */ |
| 997 | #define SKIPSPC do { while (*p && isspace(UC(*p))) p++; } while (0) |
| 998 | |
| 999 | /* Set Q to point to the next word following P, null-terminate it, and step P |
| 1000 | * past it. */ |
| 1001 | #define NEXTWORD(q) do { \ |
| 1002 | SKIPSPC; \ |
| 1003 | q = p; \ |
| 1004 | while (*p && !isspace(UC(*p))) p++; \ |
| 1005 | if (*p) *p++ = 0; \ |
| 1006 | } while (0) |
| 1007 | |
| 1008 | /* Set Q to point to the next dotted-quad address, store the ending delimiter |
| 1009 | * in DEL, null-terminate it, and step P past it. */ |
| 1010 | static void parse_nextaddr(char **pp, char **qq, int *del) |
| 1011 | { |
| 1012 | char *p = *pp; |
| 1013 | |
| 1014 | SKIPSPC; |
| 1015 | if (*p == '[') { |
| 1016 | p++; SKIPSPC; |
| 1017 | *qq = p; |
| 1018 | p += strcspn(p, "]"); |
| 1019 | if (*p) *p++ = 0; |
| 1020 | *del = 0; |
| 1021 | } else { |
| 1022 | *qq = p; |
| 1023 | while (*p && (*p == '.' || isdigit(UC(*p)))) p++; |
| 1024 | *del = *p; |
| 1025 | if (*p) *p++ = 0; |
| 1026 | } |
| 1027 | *pp = p; |
| 1028 | } |
| 1029 | |
| 1030 | /* Set Q to point to the next decimal number, store the ending delimiter in |
| 1031 | * DEL, null-terminate it, and step P past it. */ |
| 1032 | #define NEXTNUMBER(q, del) do { \ |
| 1033 | SKIPSPC; \ |
| 1034 | q = p; \ |
| 1035 | while (*p && isdigit(UC(*p))) p++; \ |
| 1036 | del = *p; \ |
| 1037 | if (*p) *p++ = 0; \ |
| 1038 | } while (0) |
| 1039 | |
| 1040 | /* Push the character DEL back so we scan it again, unless it's zero |
| 1041 | * (end-of-file). */ |
| 1042 | #define RESCAN(del) do { if (del) *--p = del; } while (0) |
| 1043 | |
| 1044 | /* Evaluate true if P is pointing to the word KW (and not some longer string |
| 1045 | * of which KW is a prefix). */ |
| 1046 | |
| 1047 | #define KWMATCHP(kw) (strncmp(p, kw, sizeof(kw) - 1) == 0 && \ |
| 1048 | !isalnum(UC(p[sizeof(kw) - 1])) && \ |
| 1049 | (p += sizeof(kw) - 1)) |
| 1050 | |
| 1051 | /* Parse a port list, starting at *PP. Port lists have the form |
| 1052 | * [:LOW[-HIGH]]: if omitted, all ports are included; if HIGH is omitted, |
| 1053 | * it's as if HIGH = LOW. Store LOW in *MIN, HIGH in *MAX and set *PP to the |
| 1054 | * rest of the string. |
| 1055 | */ |
| 1056 | static void parse_ports(char **pp, unsigned short *min, unsigned short *max) |
| 1057 | { |
| 1058 | char *p = *pp, *q; |
| 1059 | int del; |
| 1060 | |
| 1061 | SKIPSPC; |
| 1062 | if (*p != ':') |
| 1063 | { *min = 0; *max = 0xffff; } |
| 1064 | else { |
| 1065 | p++; |
| 1066 | NEXTNUMBER(q, del); *min = strtoul(q, 0, 0); RESCAN(del); |
| 1067 | SKIPSPC; |
| 1068 | if (*p == '-') |
| 1069 | { p++; NEXTNUMBER(q, del); *max = strtoul(q, 0, 0); RESCAN(del); } |
| 1070 | else |
| 1071 | *max = *min; |
| 1072 | } |
| 1073 | *pp = p; |
| 1074 | } |
| 1075 | |
| 1076 | /* Parse an address range designator starting at PP and store a |
| 1077 | * representation of it in R. An address range designator has the form: |
| 1078 | * |
| 1079 | * any | local | ADDR | ADDR - ADDR | ADDR/ADDR | ADDR/INT |
| 1080 | */ |
| 1081 | static int parse_addrrange(char **pp, addrrange *r) |
| 1082 | { |
| 1083 | char *p = *pp, *q; |
| 1084 | int n; |
| 1085 | int del; |
| 1086 | int af; |
| 1087 | |
| 1088 | SKIPSPC; |
| 1089 | if (KWMATCHP("any")) r->type = ANY; |
| 1090 | else if (KWMATCHP("local")) r->type = LOCAL; |
| 1091 | else { |
| 1092 | parse_nextaddr(&p, &q, &del); |
| 1093 | af = guess_address_family(q); |
| 1094 | if (inet_pton(af, q, &r->u.range.min) <= 0) goto bad; |
| 1095 | RESCAN(del); |
| 1096 | SKIPSPC; |
| 1097 | if (*p == '-') { |
| 1098 | p++; |
| 1099 | parse_nextaddr(&p, &q, &del); |
| 1100 | if (inet_pton(af, q, &r->u.range.max) <= 0) goto bad; |
| 1101 | RESCAN(del); |
| 1102 | } else if (*p == '/') { |
| 1103 | p++; |
| 1104 | NEXTNUMBER(q, del); |
| 1105 | n = strtoul(q, 0, 0); |
| 1106 | r->u.range.max = r->u.range.min; |
| 1107 | mask_address(af, &r->u.range.min, n, 0); |
| 1108 | mask_address(af, &r->u.range.max, n, 1); |
| 1109 | RESCAN(del); |
| 1110 | } else |
| 1111 | r->u.range.max = r->u.range.min; |
| 1112 | r->type = RANGE; |
| 1113 | r->u.range.af = af; |
| 1114 | } |
| 1115 | *pp = p; |
| 1116 | return (0); |
| 1117 | |
| 1118 | bad: |
| 1119 | return (-1); |
| 1120 | } |
| 1121 | |
| 1122 | /* Call FUNC on each individual address range in R. */ |
| 1123 | static void foreach_addrrange(const addrrange *r, |
| 1124 | void (*func)(int af, |
| 1125 | const ipaddr *min, |
| 1126 | const ipaddr *max, |
| 1127 | void *p), |
| 1128 | void *p) |
| 1129 | { |
| 1130 | ipaddr minaddr, maxaddr; |
| 1131 | int i, af; |
| 1132 | |
| 1133 | switch (r->type) { |
| 1134 | case EMPTY: |
| 1135 | break; |
| 1136 | case ANY: |
| 1137 | for (i = 0; address_families[i] >= 0; i++) { |
| 1138 | af = address_families[i]; |
| 1139 | memset(&minaddr, 0, sizeof(minaddr)); |
| 1140 | maxaddr = minaddr; mask_address(af, &maxaddr, 0, 1); |
| 1141 | func(af, &minaddr, &maxaddr, p); |
| 1142 | } |
| 1143 | break; |
| 1144 | case LOCAL: |
| 1145 | for (i = 0; address_families[i] >= 0; i++) { |
| 1146 | af = address_families[i]; |
| 1147 | memset(&minaddr, 0, sizeof(minaddr)); |
| 1148 | maxaddr = minaddr; mask_address(af, &maxaddr, 0, 1); |
| 1149 | func(af, &minaddr, &minaddr, p); |
| 1150 | func(af, &maxaddr, &maxaddr, p); |
| 1151 | } |
| 1152 | for (i = 0; i < n_local_ipaddrs; i++) { |
| 1153 | func(local_ipaddrs[i].af, |
| 1154 | &local_ipaddrs[i].addr, &local_ipaddrs[i].addr, |
| 1155 | p); |
| 1156 | } |
| 1157 | break; |
| 1158 | case RANGE: |
| 1159 | func(r->u.range.af, &r->u.range.min, &r->u.range.max, p); |
| 1160 | break; |
| 1161 | default: |
| 1162 | abort(); |
| 1163 | } |
| 1164 | } |
| 1165 | |
| 1166 | struct add_aclnode_ctx { |
| 1167 | int act; |
| 1168 | unsigned short minport, maxport; |
| 1169 | aclnode ***tail; |
| 1170 | }; |
| 1171 | |
| 1172 | static void add_aclnode(int af, const ipaddr *min, const ipaddr *max, |
| 1173 | void *p) |
| 1174 | { |
| 1175 | struct add_aclnode_ctx *ctx = p; |
| 1176 | aclnode *a; |
| 1177 | |
| 1178 | NEW(a); |
| 1179 | a->act = ctx->act; |
| 1180 | a->af = af; |
| 1181 | a->minaddr = *min; a->maxaddr = *max; |
| 1182 | a->minport = ctx->minport; a->maxport = ctx->maxport; |
| 1183 | **ctx->tail = a; *ctx->tail = &a->next; |
| 1184 | } |
| 1185 | |
| 1186 | /* Parse an ACL line. *PP points to the end of the line; *TAIL points to |
| 1187 | * the list tail (i.e., the final link in the list). An ACL entry has the |
| 1188 | * form +|- ADDR-RANGE PORTS |
| 1189 | * where PORTS is parsed by parse_ports above; an ACL line consists of a |
| 1190 | * comma-separated sequence of entries.. |
| 1191 | */ |
| 1192 | static void parse_acl_line(char **pp, aclnode ***tail) |
| 1193 | { |
| 1194 | struct add_aclnode_ctx ctx; |
| 1195 | addrrange r; |
| 1196 | char *p = *pp; |
| 1197 | |
| 1198 | ctx.tail = tail; |
| 1199 | for (;;) { |
| 1200 | SKIPSPC; |
| 1201 | if (*p == '+') ctx.act = ALLOW; |
| 1202 | else if (*p == '-') ctx.act = DENY; |
| 1203 | else goto bad; |
| 1204 | |
| 1205 | p++; |
| 1206 | if (parse_addrrange(&p, &r)) goto bad; |
| 1207 | parse_ports(&p, &ctx.minport, &ctx.maxport); |
| 1208 | foreach_addrrange(&r, add_aclnode, &ctx); |
| 1209 | SKIPSPC; |
| 1210 | if (*p != ',') break; |
| 1211 | if (*p) p++; |
| 1212 | } |
| 1213 | if (*p) goto bad; |
| 1214 | *pp = p; |
| 1215 | return; |
| 1216 | |
| 1217 | bad: |
| 1218 | D( fprintf(stderr, "noip(%d): bad acl spec (ignored)\n", getpid()); ) |
| 1219 | return; |
| 1220 | } |
| 1221 | |
| 1222 | /* Parse an ACL from an environment variable VAR, attaching it to the list |
| 1223 | * TAIL. |
| 1224 | */ |
| 1225 | static void parse_acl_env(const char *var, aclnode ***tail) |
| 1226 | { |
| 1227 | char *p, *q; |
| 1228 | |
| 1229 | if ((p = getenv(var)) != 0) { |
| 1230 | p = q = xstrdup(p); |
| 1231 | parse_acl_line(&q, tail); |
| 1232 | free(p); |
| 1233 | } |
| 1234 | } |
| 1235 | |
| 1236 | struct add_impbind_ctx { |
| 1237 | int af, how; |
| 1238 | ipaddr addr; |
| 1239 | }; |
| 1240 | |
| 1241 | static void add_impbind(int af, const ipaddr *min, const ipaddr *max, |
| 1242 | void *p) |
| 1243 | { |
| 1244 | struct add_impbind_ctx *ctx = p; |
| 1245 | impbind *i; |
| 1246 | |
| 1247 | if (ctx->af && af != ctx->af) return; |
| 1248 | NEW(i); |
| 1249 | i->af = af; |
| 1250 | i->how = ctx->how; |
| 1251 | i->minaddr = *min; i->maxaddr = *max; |
| 1252 | switch (ctx->how) { |
| 1253 | case EXPLICIT: i->bindaddr = ctx->addr; |
| 1254 | case SAME: break; |
| 1255 | default: abort(); |
| 1256 | } |
| 1257 | *impbind_tail = i; impbind_tail = &i->next; |
| 1258 | } |
| 1259 | |
| 1260 | /* Parse an implicit-bind line. An implicit-bind entry has the form |
| 1261 | * ADDR-RANGE {ADDR | same} |
| 1262 | */ |
| 1263 | static void parse_impbind_line(char **pp) |
| 1264 | { |
| 1265 | struct add_impbind_ctx ctx; |
| 1266 | char *p = *pp, *q; |
| 1267 | addrrange r; |
| 1268 | int del; |
| 1269 | |
| 1270 | for (;;) { |
| 1271 | if (parse_addrrange(&p, &r)) goto bad; |
| 1272 | SKIPSPC; |
| 1273 | if (KWMATCHP("same")) { |
| 1274 | ctx.how = SAME; |
| 1275 | ctx.af = 0; |
| 1276 | } else { |
| 1277 | ctx.how = EXPLICIT; |
| 1278 | parse_nextaddr(&p, &q, &del); |
| 1279 | ctx.af = guess_address_family(q); |
| 1280 | if (inet_pton(ctx.af, q, &ctx.addr) < 0) goto bad; |
| 1281 | RESCAN(del); |
| 1282 | } |
| 1283 | foreach_addrrange(&r, add_impbind, &ctx); |
| 1284 | SKIPSPC; |
| 1285 | if (*p != ',') break; |
| 1286 | if (*p) p++; |
| 1287 | } |
| 1288 | if (*p) goto bad; |
| 1289 | *pp = p; |
| 1290 | return; |
| 1291 | |
| 1292 | bad: |
| 1293 | D( fprintf(stderr, "noip(%d): bad implicit-bind spec (ignored)\n", |
| 1294 | getpid()); ) |
| 1295 | return; |
| 1296 | } |
| 1297 | |
| 1298 | /* Parse implicit-bind instructions from an environment variable VAR, |
| 1299 | * attaching it to the list. |
| 1300 | */ |
| 1301 | static void parse_impbind_env(const char *var) |
| 1302 | { |
| 1303 | char *p, *q; |
| 1304 | |
| 1305 | if ((p = getenv(var)) != 0) { |
| 1306 | p = q = xstrdup(p); |
| 1307 | parse_impbind_line(&q); |
| 1308 | free(p); |
| 1309 | } |
| 1310 | } |
| 1311 | |
| 1312 | /* Parse the autoports configuration directive. Syntax is MIN - MAX. */ |
| 1313 | static void parse_autoports(char **pp) |
| 1314 | { |
| 1315 | char *p = *pp, *q; |
| 1316 | unsigned x, y; |
| 1317 | int del; |
| 1318 | |
| 1319 | SKIPSPC; |
| 1320 | NEXTNUMBER(q, del); x = strtoul(q, 0, 0); RESCAN(del); |
| 1321 | SKIPSPC; |
| 1322 | if (*p != '-') goto bad; |
| 1323 | p++; |
| 1324 | NEXTNUMBER(q, del); y = strtoul(q, 0, 0); RESCAN(del); |
| 1325 | minautoport = x; maxautoport = y; |
| 1326 | SKIPSPC; if (*p) goto bad; |
| 1327 | *pp = p; |
| 1328 | return; |
| 1329 | |
| 1330 | bad: |
| 1331 | D( fprintf(stderr, "noip(%d): bad port range (ignored)\n", getpid()); ) |
| 1332 | return; |
| 1333 | } |
| 1334 | |
| 1335 | /* Read the configuration from the config file and environment. */ |
| 1336 | static void readconfig(void) |
| 1337 | { |
| 1338 | FILE *fp; |
| 1339 | char buf[1024]; |
| 1340 | size_t n; |
| 1341 | char *p, *q, *cmd; |
| 1342 | Dpid; |
| 1343 | |
| 1344 | parse_acl_env("NOIP_REALBIND_BEFORE", &bind_tail); |
| 1345 | parse_acl_env("NOIP_REALCONNECT_BEFORE", &connect_tail); |
| 1346 | parse_impbind_env("NOIP_IMPBIND_BEFORE"); |
| 1347 | if ((p = getenv("NOIP_AUTOPORTS")) != 0) { |
| 1348 | p = q = xstrdup(p); |
| 1349 | parse_autoports(&q); |
| 1350 | free(p); |
| 1351 | } |
| 1352 | if ((p = getenv("NOIP_CONFIG")) == 0) |
| 1353 | snprintf(p = buf, sizeof(buf), "%s/.noip", home()); |
| 1354 | D( fprintf(stderr, "noip(%d): config file: %s\n", pid, p); ) |
| 1355 | |
| 1356 | if ((fp = fopen(p, "r")) == 0) { |
| 1357 | D( fprintf(stderr, "noip(%d): couldn't read config: %s\n", |
| 1358 | pid, strerror(errno)); ) |
| 1359 | goto done; |
| 1360 | } |
| 1361 | while (fgets(buf, sizeof(buf), fp)) { |
| 1362 | n = strlen(buf); |
| 1363 | p = buf; |
| 1364 | |
| 1365 | SKIPSPC; |
| 1366 | if (!*p || *p == '#') continue; |
| 1367 | while (n && isspace(UC(buf[n - 1]))) n--; |
| 1368 | buf[n] = 0; |
| 1369 | NEXTWORD(cmd); |
| 1370 | SKIPSPC; |
| 1371 | |
| 1372 | if (strcmp(cmd, "socketdir") == 0) |
| 1373 | sockdir = xstrdup(p); |
| 1374 | else if (strcmp(cmd, "realbind") == 0) |
| 1375 | parse_acl_line(&p, &bind_tail); |
| 1376 | else if (strcmp(cmd, "realconnect") == 0) |
| 1377 | parse_acl_line(&p, &connect_tail); |
| 1378 | else if (strcmp(cmd, "impbind") == 0) |
| 1379 | parse_impbind_line(&p); |
| 1380 | else if (strcmp(cmd, "autoports") == 0) |
| 1381 | parse_autoports(&p); |
| 1382 | else if (strcmp(cmd, "debug") == 0) |
| 1383 | debug = *p ? atoi(p) : 1; |
| 1384 | else |
| 1385 | D( fprintf(stderr, "noip(%d): bad config command %s\n", pid, cmd); ) |
| 1386 | } |
| 1387 | fclose(fp); |
| 1388 | |
| 1389 | done: |
| 1390 | parse_acl_env("NOIP_REALBIND", &bind_tail); |
| 1391 | parse_acl_env("NOIP_REALCONNECT", &connect_tail); |
| 1392 | parse_impbind_env("NOIP_IMPBIND"); |
| 1393 | parse_acl_env("NOIP_REALBIND_AFTER", &bind_tail); |
| 1394 | parse_acl_env("NOIP_REALCONNECT_AFTER", &connect_tail); |
| 1395 | parse_impbind_env("NOIP_IMPBIND_AFTER"); |
| 1396 | *bind_tail = 0; |
| 1397 | *connect_tail = 0; |
| 1398 | *impbind_tail = 0; |
| 1399 | if (!sockdir) sockdir = getenv("NOIP_SOCKETDIR"); |
| 1400 | if (!sockdir) { |
| 1401 | snprintf(buf, sizeof(buf), "%s/noip-%s", tmpdir(), user()); |
| 1402 | sockdir = xstrdup(buf); |
| 1403 | } |
| 1404 | D( fprintf(stderr, "noip(%d): socketdir: %s\n", pid, sockdir); |
| 1405 | fprintf(stderr, "noip(%d): autoports: %u-%u\n", |
| 1406 | pid, minautoport, maxautoport); |
| 1407 | fprintf(stderr, "noip(%d): realbind acl:\n", pid); |
| 1408 | dump_acl(bind_real); |
| 1409 | fprintf(stderr, "noip(%d): realconnect acl:\n", pid); |
| 1410 | dump_acl(connect_real); |
| 1411 | fprintf(stderr, "noip(%d): impbind list:\n", pid); |
| 1412 | dump_impbind_list(); ) |
| 1413 | } |
| 1414 | |
| 1415 | /*----- Overridden system calls -------------------------------------------*/ |
| 1416 | |
| 1417 | static void dump_syserr(long rc) |
| 1418 | { fprintf(stderr, " => %ld (E%d)\n", rc, errno); } |
| 1419 | |
| 1420 | static void dump_sysresult(long rc) |
| 1421 | { |
| 1422 | if (rc < 0) dump_syserr(rc); |
| 1423 | else fprintf(stderr, " => %ld\n", rc); |
| 1424 | } |
| 1425 | |
| 1426 | static void dump_addrresult(long rc, const struct sockaddr *sa, |
| 1427 | socklen_t len) |
| 1428 | { |
| 1429 | char addrbuf[ADDRBUFSZ]; |
| 1430 | |
| 1431 | if (rc < 0) dump_syserr(rc); |
| 1432 | else { |
| 1433 | fprintf(stderr, " => %ld [%s]\n", rc, |
| 1434 | present_sockaddr(sa, len, addrbuf, sizeof(addrbuf))); |
| 1435 | } |
| 1436 | } |
| 1437 | |
| 1438 | int socket(int pf, int ty, int proto) |
| 1439 | { |
| 1440 | int sk; |
| 1441 | |
| 1442 | D( fprintf(stderr, "noip(%d): SOCKET pf=%d, type=%d, proto=%d", |
| 1443 | getpid(), pf, ty, proto); ) |
| 1444 | |
| 1445 | switch (pf) { |
| 1446 | default: |
| 1447 | if (!family_known_p(pf)) { |
| 1448 | D( fprintf(stderr, " -> unknown; refuse\n"); ) |
| 1449 | errno = EAFNOSUPPORT; |
| 1450 | sk = -1; |
| 1451 | } |
| 1452 | D( fprintf(stderr, " -> inet; substitute"); ) |
| 1453 | pf = PF_UNIX; |
| 1454 | proto = 0; |
| 1455 | break; |
| 1456 | case PF_UNIX: |
| 1457 | #ifdef PF_NETLINK |
| 1458 | case PF_NETLINK: |
| 1459 | #endif |
| 1460 | D( fprintf(stderr, " -> safe; permit"); ) |
| 1461 | break; |
| 1462 | } |
| 1463 | sk = real_socket(pf, ty, proto); |
| 1464 | D( dump_sysresult(sk); ) |
| 1465 | return (sk); |
| 1466 | } |
| 1467 | |
| 1468 | int socketpair(int pf, int ty, int proto, int *sk) |
| 1469 | { |
| 1470 | int rc; |
| 1471 | |
| 1472 | D( fprintf(stderr, "noip(%d): SOCKETPAIR pf=%d, type=%d, proto=%d", |
| 1473 | getpid(), pf, ty, proto); ) |
| 1474 | if (!family_known_p(pf)) |
| 1475 | D( fprintf(stderr, " -> unknown; permit"); ) |
| 1476 | else { |
| 1477 | D( fprintf(stderr, " -> inet; substitute"); ) |
| 1478 | pf = PF_UNIX; |
| 1479 | proto = 0; |
| 1480 | } |
| 1481 | rc = real_socketpair(pf, ty, proto, sk); |
| 1482 | D( if (rc < 0) dump_syserr(rc); |
| 1483 | else fprintf(stderr, " => %d (%d, %d)\n", rc, sk[0], sk[1]); ) |
| 1484 | return (rc); |
| 1485 | } |
| 1486 | |
| 1487 | int bind(int sk, const struct sockaddr *sa, socklen_t len) |
| 1488 | { |
| 1489 | struct sockaddr_un sun; |
| 1490 | int rc; |
| 1491 | Dpid; |
| 1492 | |
| 1493 | D({ char buf[ADDRBUFSZ]; |
| 1494 | fprintf(stderr, "noip(%d): BIND sk=%d, sa[%d]=%s", pid, |
| 1495 | sk, len, present_sockaddr(sa, len, buf, sizeof(buf))); }) |
| 1496 | |
| 1497 | if (!family_known_p(sa->sa_family)) |
| 1498 | D( fprintf(stderr, " -> unknown af; pass through"); ) |
| 1499 | else { |
| 1500 | D( fprintf(stderr, " -> checking...\n"); ) |
| 1501 | PRESERVING_ERRNO({ |
| 1502 | if (acl_allows_p(bind_real, sa)) { |
| 1503 | if (fixup_real_ip_socket(sk, sa->sa_family, 0)) |
| 1504 | return (-1); |
| 1505 | } else { |
| 1506 | encode_inet_addr(&sun, sa, ENCF_FRESH); |
| 1507 | sa = SA(&sun); |
| 1508 | len = SUN_LEN(&sun); |
| 1509 | } |
| 1510 | }); |
| 1511 | D( fprintf(stderr, "noip(%d): BIND ...", pid); ) |
| 1512 | } |
| 1513 | rc = real_bind(sk, sa, len); |
| 1514 | D( dump_sysresult(rc); ) |
| 1515 | return (rc); |
| 1516 | } |
| 1517 | |
| 1518 | int connect(int sk, const struct sockaddr *sa, socklen_t len) |
| 1519 | { |
| 1520 | struct sockaddr_un sun; |
| 1521 | int rc; |
| 1522 | Dpid; |
| 1523 | |
| 1524 | D({ char buf[ADDRBUFSZ]; |
| 1525 | fprintf(stderr, "noip(%d): CONNECT sk=%d, sa[%d]=%s", pid, |
| 1526 | sk, len, present_sockaddr(sa, len, buf, sizeof(buf))); }) |
| 1527 | |
| 1528 | if (!family_known_p(sa->sa_family)) { |
| 1529 | D( fprintf(stderr, " -> unknown af; pass through"); ) |
| 1530 | rc = real_connect(sk, sa, len); |
| 1531 | } else { |
| 1532 | D( fprintf(stderr, " -> checking...\n"); ) |
| 1533 | PRESERVING_ERRNO({ |
| 1534 | do_implicit_bind(sk, &sa, &len, &sun); |
| 1535 | }); |
| 1536 | D( fprintf(stderr, "noip(%d): CONNECT ...", pid); ) |
| 1537 | rc = real_connect(sk, sa, len); |
| 1538 | if (rc < 0) { |
| 1539 | switch (errno) { |
| 1540 | case ENOENT: errno = ECONNREFUSED; break; |
| 1541 | } |
| 1542 | } |
| 1543 | } |
| 1544 | D( dump_sysresult(rc); ) |
| 1545 | return (rc); |
| 1546 | } |
| 1547 | |
| 1548 | ssize_t sendto(int sk, const void *buf, size_t len, int flags, |
| 1549 | const struct sockaddr *to, socklen_t tolen) |
| 1550 | { |
| 1551 | struct sockaddr_un sun; |
| 1552 | ssize_t n; |
| 1553 | Dpid; |
| 1554 | |
| 1555 | D({ char addrbuf[ADDRBUFSZ]; |
| 1556 | fprintf(stderr, "noip(%d): SENDTO sk=%d, len=%lu, flags=%d, to[%d]=%s", |
| 1557 | pid, sk, (unsigned long)len, flags, tolen, |
| 1558 | present_sockaddr(to, tolen, addrbuf, sizeof(addrbuf))); }) |
| 1559 | |
| 1560 | if (!to) |
| 1561 | D( fprintf(stderr, " -> null address; leaving"); ) |
| 1562 | else if (!family_known_p(to->sa_family)) |
| 1563 | D( fprintf(stderr, " -> unknown af; pass through"); ) |
| 1564 | else { |
| 1565 | D( fprintf(stderr, " -> checking...\n"); ) |
| 1566 | PRESERVING_ERRNO({ |
| 1567 | do_implicit_bind(sk, &to, &tolen, &sun); |
| 1568 | }); |
| 1569 | D( fprintf(stderr, "noip(%d): SENDTO ...", pid); ) |
| 1570 | } |
| 1571 | n = real_sendto(sk, buf, len, flags, to, tolen); |
| 1572 | D( dump_sysresult(n); ) |
| 1573 | return (n); |
| 1574 | } |
| 1575 | |
| 1576 | ssize_t recvfrom(int sk, void *buf, size_t len, int flags, |
| 1577 | struct sockaddr *from, socklen_t *fromlen) |
| 1578 | { |
| 1579 | char sabuf[1024]; |
| 1580 | socklen_t mylen = sizeof(sabuf); |
| 1581 | ssize_t n; |
| 1582 | Dpid; |
| 1583 | |
| 1584 | D( fprintf(stderr, "noip(%d): RECVFROM sk=%d, len=%lu, flags=%d", |
| 1585 | pid, sk, (unsigned long)len, flags); ) |
| 1586 | |
| 1587 | if (!from) { |
| 1588 | D( fprintf(stderr, " -> null addr; pass through"); ) |
| 1589 | n = real_recvfrom(sk, buf, len, flags, 0, 0); |
| 1590 | } else { |
| 1591 | PRESERVING_ERRNO({ |
| 1592 | n = real_recvfrom(sk, buf, len, flags, SA(sabuf), &mylen); |
| 1593 | if (n >= 0) { |
| 1594 | D( fprintf(stderr, " -> converting...\n"); ) |
| 1595 | return_fake_name(SA(sabuf), mylen, from, fromlen); |
| 1596 | D( fprintf(stderr, "noip(%d): ... RECVFROM", pid); ) |
| 1597 | } |
| 1598 | }); |
| 1599 | } |
| 1600 | D( dump_addrresult(n, from, fromlen ? *fromlen : 0); ) |
| 1601 | return (n); |
| 1602 | } |
| 1603 | |
| 1604 | ssize_t sendmsg(int sk, const struct msghdr *msg, int flags) |
| 1605 | { |
| 1606 | struct sockaddr_un sun; |
| 1607 | const struct sockaddr *sa = SA(msg->msg_name); |
| 1608 | struct msghdr mymsg; |
| 1609 | ssize_t n; |
| 1610 | Dpid; |
| 1611 | |
| 1612 | D({ char addrbuf[ADDRBUFSZ]; |
| 1613 | fprintf(stderr, "noip(%d): SENDMSG sk=%d, " |
| 1614 | "msg_flags=%d, msg_name[%d]=%s, ...", |
| 1615 | pid, sk, msg->msg_flags, msg->msg_namelen, |
| 1616 | present_sockaddr(sa, msg->msg_namelen, |
| 1617 | addrbuf, sizeof(addrbuf))); }) |
| 1618 | |
| 1619 | if (!sa) |
| 1620 | D( fprintf(stderr, " -> null address; leaving"); ) |
| 1621 | else if (!family_known_p(sa->sa_family)) |
| 1622 | D( fprintf(stderr, " -> unknown af; pass through"); ) |
| 1623 | else { |
| 1624 | D( fprintf(stderr, " -> checking...\n"); ) |
| 1625 | PRESERVING_ERRNO({ |
| 1626 | mymsg = *msg; |
| 1627 | do_implicit_bind(sk, &sa, &mymsg.msg_namelen, &sun); |
| 1628 | mymsg.msg_name = SA(sa); |
| 1629 | msg = &mymsg; |
| 1630 | }); |
| 1631 | D( fprintf(stderr, "noip(%d): SENDMSG ...", pid); ) |
| 1632 | } |
| 1633 | n = real_sendmsg(sk, msg, flags); |
| 1634 | D( dump_sysresult(n); ) |
| 1635 | return (n); |
| 1636 | } |
| 1637 | |
| 1638 | ssize_t recvmsg(int sk, struct msghdr *msg, int flags) |
| 1639 | { |
| 1640 | char sabuf[1024]; |
| 1641 | struct sockaddr *sa = SA(msg->msg_name); |
| 1642 | socklen_t len = msg->msg_namelen; |
| 1643 | ssize_t n; |
| 1644 | Dpid; |
| 1645 | |
| 1646 | D( fprintf(stderr, "noip(%d): RECVMSG sk=%d msg_flags=%d, ...", |
| 1647 | pid, sk, msg->msg_flags); ) |
| 1648 | |
| 1649 | if (!msg->msg_name) { |
| 1650 | D( fprintf(stderr, " -> null addr; pass through"); ) |
| 1651 | return (real_recvmsg(sk, msg, flags)); |
| 1652 | } else { |
| 1653 | PRESERVING_ERRNO({ |
| 1654 | msg->msg_name = sabuf; |
| 1655 | msg->msg_namelen = sizeof(sabuf); |
| 1656 | n = real_recvmsg(sk, msg, flags); |
| 1657 | if (n >= 0) { |
| 1658 | D( fprintf(stderr, " -> converting...\n"); ) |
| 1659 | return_fake_name(SA(sabuf), msg->msg_namelen, sa, &len); |
| 1660 | D( fprintf(stderr, "noip(%d): ... RECVMSG", pid); ) |
| 1661 | } |
| 1662 | msg->msg_name = sa; |
| 1663 | msg->msg_namelen = len; |
| 1664 | }); |
| 1665 | } |
| 1666 | D( dump_addrresult(n, sa, len); ) |
| 1667 | return (n); |
| 1668 | } |
| 1669 | |
| 1670 | int accept(int sk, struct sockaddr *sa, socklen_t *len) |
| 1671 | { |
| 1672 | char sabuf[1024]; |
| 1673 | socklen_t mylen = sizeof(sabuf); |
| 1674 | int nsk; |
| 1675 | Dpid; |
| 1676 | |
| 1677 | D( fprintf(stderr, "noip(%d): ACCEPT sk=%d", pid, sk); ) |
| 1678 | |
| 1679 | nsk = real_accept(sk, SA(sabuf), &mylen); |
| 1680 | if (nsk < 0) /* failed */; |
| 1681 | else if (!sa) D( fprintf(stderr, " -> address not wanted"); ) |
| 1682 | else { |
| 1683 | D( fprintf(stderr, " -> converting...\n"); ) |
| 1684 | return_fake_name(SA(sabuf), mylen, sa, len); |
| 1685 | D( fprintf(stderr, "noip(%d): ... ACCEPT", pid); ) |
| 1686 | } |
| 1687 | D( dump_addrresult(nsk, sa, len ? *len : 0); ) |
| 1688 | return (nsk); |
| 1689 | } |
| 1690 | |
| 1691 | int getsockname(int sk, struct sockaddr *sa, socklen_t *len) |
| 1692 | { |
| 1693 | char sabuf[1024]; |
| 1694 | socklen_t mylen = sizeof(sabuf); |
| 1695 | int rc; |
| 1696 | Dpid; |
| 1697 | |
| 1698 | D( fprintf(stderr, "noip(%d): GETSOCKNAME sk=%d", pid, sk); ) |
| 1699 | rc = real_getsockname(sk, SA(sabuf), &mylen); |
| 1700 | if (rc >= 0) { |
| 1701 | D( fprintf(stderr, " -> converting...\n"); ) |
| 1702 | return_fake_name(SA(sabuf), mylen, sa, len); |
| 1703 | D( fprintf(stderr, "noip(%d): ... GETSOCKNAME", pid); ) |
| 1704 | } |
| 1705 | D( dump_addrresult(rc, sa, *len); ) |
| 1706 | return (rc); |
| 1707 | } |
| 1708 | |
| 1709 | int getpeername(int sk, struct sockaddr *sa, socklen_t *len) |
| 1710 | { |
| 1711 | char sabuf[1024]; |
| 1712 | socklen_t mylen = sizeof(sabuf); |
| 1713 | int rc; |
| 1714 | Dpid; |
| 1715 | |
| 1716 | D( fprintf(stderr, "noip(%d): GETPEERNAME sk=%d", pid, sk); ) |
| 1717 | rc = real_getpeername(sk, SA(sabuf), &mylen); |
| 1718 | if (rc >= 0) { |
| 1719 | D( fprintf(stderr, " -> converting...\n"); ) |
| 1720 | return_fake_name(SA(sabuf), mylen, sa, len); |
| 1721 | D( fprintf(stderr, "noip(%d): ... GETPEERNAME", pid); ) |
| 1722 | } |
| 1723 | D( dump_addrresult(rc, sa, *len); ) |
| 1724 | return (0); |
| 1725 | } |
| 1726 | |
| 1727 | int getsockopt(int sk, int lev, int opt, void *p, socklen_t *len) |
| 1728 | { |
| 1729 | switch (lev) { |
| 1730 | case IPPROTO_IP: |
| 1731 | case IPPROTO_IPV6: |
| 1732 | case IPPROTO_TCP: |
| 1733 | case IPPROTO_UDP: |
| 1734 | if (*len > 0) |
| 1735 | memset(p, 0, *len); |
| 1736 | return (0); |
| 1737 | } |
| 1738 | return (real_getsockopt(sk, lev, opt, p, len)); |
| 1739 | } |
| 1740 | |
| 1741 | int setsockopt(int sk, int lev, int opt, const void *p, socklen_t len) |
| 1742 | { |
| 1743 | switch (lev) { |
| 1744 | case IPPROTO_IP: |
| 1745 | case IPPROTO_IPV6: |
| 1746 | case IPPROTO_TCP: |
| 1747 | case IPPROTO_UDP: |
| 1748 | return (0); |
| 1749 | } |
| 1750 | switch (opt) { |
| 1751 | case SO_BINDTODEVICE: |
| 1752 | case SO_ATTACH_FILTER: |
| 1753 | case SO_DETACH_FILTER: |
| 1754 | return (0); |
| 1755 | } |
| 1756 | return (real_setsockopt(sk, lev, opt, p, len)); |
| 1757 | } |
| 1758 | |
| 1759 | int ioctl(int fd, unsigned long op, ...) |
| 1760 | { |
| 1761 | va_list ap; |
| 1762 | void *arg; |
| 1763 | int sk; |
| 1764 | int rc; |
| 1765 | |
| 1766 | va_start(ap, op); |
| 1767 | arg = va_arg(ap, void *); |
| 1768 | |
| 1769 | switch (op) { |
| 1770 | case SIOCGIFADDR: |
| 1771 | case SIOCGIFBRDADDR: |
| 1772 | case SIOCGIFDSTADDR: |
| 1773 | case SIOCGIFNETMASK: |
| 1774 | PRESERVING_ERRNO({ |
| 1775 | if (fixup_real_ip_socket(fd, AF_INET, &sk)) goto real; |
| 1776 | }); |
| 1777 | rc = real_ioctl(sk, op, arg); |
| 1778 | PRESERVING_ERRNO({ close(sk); }); |
| 1779 | break; |
| 1780 | default: |
| 1781 | real: |
| 1782 | rc = real_ioctl(fd, op, arg); |
| 1783 | break; |
| 1784 | } |
| 1785 | va_end(ap); |
| 1786 | return (rc); |
| 1787 | } |
| 1788 | |
| 1789 | /*----- Initialization ----------------------------------------------------*/ |
| 1790 | |
| 1791 | /* Clean up the socket directory, deleting stale sockets. */ |
| 1792 | static void cleanup_sockdir(void) |
| 1793 | { |
| 1794 | DIR *dir; |
| 1795 | struct dirent *d; |
| 1796 | address addr; |
| 1797 | struct sockaddr_un sun; |
| 1798 | struct stat st; |
| 1799 | Dpid; |
| 1800 | |
| 1801 | if ((dir = opendir(sockdir)) == 0) return; |
| 1802 | sun.sun_family = AF_UNIX; |
| 1803 | while ((d = readdir(dir)) != 0) { |
| 1804 | if (d->d_name[0] == '.') continue; |
| 1805 | snprintf(sun.sun_path, sizeof(sun.sun_path), |
| 1806 | "%s/%s", sockdir, d->d_name); |
| 1807 | if (decode_inet_addr(&addr.sa, 0, &sun, SUN_LEN(&sun)) || |
| 1808 | stat(sun.sun_path, &st) || |
| 1809 | !S_ISSOCK(st.st_mode)) { |
| 1810 | D( fprintf(stderr, "noip(%d): ignoring unknown socketdir entry `%s'\n", |
| 1811 | pid, sun.sun_path); ) |
| 1812 | continue; |
| 1813 | } |
| 1814 | if (unix_socket_status(&sun, 0) == STALE) { |
| 1815 | D( fprintf(stderr, "noip(%d): clearing away stale socket %s\n", |
| 1816 | pid, d->d_name); ) |
| 1817 | unlink(sun.sun_path); |
| 1818 | } |
| 1819 | } |
| 1820 | closedir(dir); |
| 1821 | } |
| 1822 | |
| 1823 | /* Find the addresses attached to local network interfaces, and remember them |
| 1824 | * in a table. |
| 1825 | */ |
| 1826 | static void get_local_ipaddrs(void) |
| 1827 | { |
| 1828 | struct ifaddrs *ifa_head, *ifa; |
| 1829 | ipaddr a; |
| 1830 | int i; |
| 1831 | Dpid; |
| 1832 | |
| 1833 | D( fprintf(stderr, "noip(%d): fetching local addresses...\n", pid); ) |
| 1834 | if (getifaddrs(&ifa_head)) { perror("getifaddrs"); return; } |
| 1835 | for (n_local_ipaddrs = 0, ifa = ifa_head; |
| 1836 | n_local_ipaddrs < MAX_LOCAL_IPADDRS && ifa; |
| 1837 | ifa = ifa->ifa_next) { |
| 1838 | if (!ifa->ifa_addr || !family_known_p(ifa->ifa_addr->sa_family)) |
| 1839 | continue; |
| 1840 | ipaddr_from_sockaddr(&a, ifa->ifa_addr); |
| 1841 | D({ char buf[ADDRBUFSZ]; |
| 1842 | fprintf(stderr, "noip(%d): local addr %s = %s", pid, |
| 1843 | ifa->ifa_name, |
| 1844 | inet_ntop(ifa->ifa_addr->sa_family, &a, |
| 1845 | buf, sizeof(buf))); }) |
| 1846 | for (i = 0; i < n_local_ipaddrs; i++) { |
| 1847 | if (ifa->ifa_addr->sa_family == local_ipaddrs[i].af && |
| 1848 | ipaddr_equal_p(local_ipaddrs[i].af, &a, &local_ipaddrs[i].addr)) { |
| 1849 | D( fprintf(stderr, " (duplicate)\n"); ) |
| 1850 | goto skip; |
| 1851 | } |
| 1852 | } |
| 1853 | D( fprintf(stderr, "\n"); ) |
| 1854 | local_ipaddrs[n_local_ipaddrs].af = ifa->ifa_addr->sa_family; |
| 1855 | local_ipaddrs[n_local_ipaddrs].addr = a; |
| 1856 | n_local_ipaddrs++; |
| 1857 | skip:; |
| 1858 | } |
| 1859 | freeifaddrs(ifa_head); |
| 1860 | } |
| 1861 | |
| 1862 | /* Print the given message to standard error. Avoids stdio. */ |
| 1863 | static void printerr(const char *p) |
| 1864 | { if (write(STDERR_FILENO, p, strlen(p))) ; } |
| 1865 | |
| 1866 | /* Create the socket directory, being careful about permissions. */ |
| 1867 | static void create_sockdir(void) |
| 1868 | { |
| 1869 | struct stat st; |
| 1870 | |
| 1871 | if (lstat(sockdir, &st)) { |
| 1872 | if (errno == ENOENT) { |
| 1873 | if (mkdir(sockdir, 0700)) { |
| 1874 | perror("noip: creating socketdir"); |
| 1875 | exit(127); |
| 1876 | } |
| 1877 | if (!lstat(sockdir, &st)) |
| 1878 | goto check; |
| 1879 | } |
| 1880 | perror("noip: checking socketdir"); |
| 1881 | exit(127); |
| 1882 | } |
| 1883 | check: |
| 1884 | if (!S_ISDIR(st.st_mode)) { |
| 1885 | printerr("noip: bad socketdir: not a directory\n"); |
| 1886 | exit(127); |
| 1887 | } |
| 1888 | if (st.st_uid != uid) { |
| 1889 | printerr("noip: bad socketdir: not owner\n"); |
| 1890 | exit(127); |
| 1891 | } |
| 1892 | if (st.st_mode & 077) { |
| 1893 | printerr("noip: bad socketdir: not private\n"); |
| 1894 | exit(127); |
| 1895 | } |
| 1896 | } |
| 1897 | |
| 1898 | /* Initialization function. */ |
| 1899 | static void setup(void) __attribute__((constructor)); |
| 1900 | static void setup(void) |
| 1901 | { |
| 1902 | PRESERVING_ERRNO({ |
| 1903 | char *p; |
| 1904 | |
| 1905 | import(); |
| 1906 | uid = geteuid(); |
| 1907 | if ((p = getenv("NOIP_DEBUG")) && atoi(p)) |
| 1908 | debug = 1; |
| 1909 | get_local_ipaddrs(); |
| 1910 | readconfig(); |
| 1911 | create_sockdir(); |
| 1912 | cleanup_sockdir(); |
| 1913 | }); |
| 1914 | } |
| 1915 | |
| 1916 | /*----- That's all, folks -------------------------------------------------*/ |