3 * Make programs use Unix-domain sockets instead of IP
5 * (c) 2008 Straylight/Edgeware
8 /*----- Licensing notice --------------------------------------------------*
10 * This file is part of the preload-hacks package.
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.
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
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.
32 /*----- Header files ------------------------------------------------------*/
47 #include <sys/ioctl.h>
48 #include <sys/socket.h>
52 #include <netinet/in.h>
53 #include <arpa/inet.h>
54 #include <netinet/tcp.h>
55 #include <netinet/udp.h>
59 /*----- Data structures ---------------------------------------------------*/
61 enum { UNUSED, STALE, USED }; /* Unix socket status values */
62 enum { WANT_FRESH, WANT_EXISTING }; /* Socket address dispositions */
63 enum { DENY, ALLOW }; /* ACL verdicts */
65 static int address_families[] = { AF_INET, -1 };
69 /* Address representations. */
70 typedef union ipaddr {
74 /* Convenient socket address hacking. */
75 typedef union address {
77 struct sockaddr_in sin;
80 /* Access control list nodes */
81 typedef struct aclnode {
85 ipaddr minaddr, maxaddr;
86 unsigned short minport, maxport;
89 /* Local address records */
90 typedef struct full_ipaddr {
94 #define MAX_LOCAL_IPADDRS 16
95 static full_ipaddr local_ipaddrs[MAX_LOCAL_IPADDRS];
96 static int n_local_ipaddrs;
98 /* General configuration */
100 static char *sockdir = 0;
101 static int debug = 0;
102 static unsigned minautoport = 16384, maxautoport = 65536;
104 /* Access control lists */
105 static aclnode *bind_real, **bind_tail = &bind_real;
106 static aclnode *connect_real, **connect_tail = &connect_real;
108 /*----- Import the real versions of functions -----------------------------*/
110 /* The list of functions to immport. */
112 _(socket, int, (int, int, int)) \
113 _(socketpair, int, (int, int, int, int *)) \
114 _(connect, int, (int, const struct sockaddr *, socklen_t)) \
115 _(bind, int, (int, const struct sockaddr *, socklen_t)) \
116 _(accept, int, (int, struct sockaddr *, socklen_t *)) \
117 _(getsockname, int, (int, struct sockaddr *, socklen_t *)) \
118 _(getpeername, int, (int, struct sockaddr *, socklen_t *)) \
119 _(getsockopt, int, (int, int, int, void *, socklen_t *)) \
120 _(setsockopt, int, (int, int, int, const void *, socklen_t)) \
121 _(sendto, ssize_t, (int, const void *buf, size_t, int, \
122 const struct sockaddr *to, socklen_t tolen)) \
123 _(recvfrom, ssize_t, (int, void *buf, size_t, int, \
124 struct sockaddr *from, socklen_t *fromlen)) \
125 _(sendmsg, ssize_t, (int, const struct msghdr *, int)) \
126 _(recvmsg, ssize_t, (int, struct msghdr *, int))
128 /* Function pointers to set up. */
129 #define DECL(imp, ret, args) static ret (*real_##imp) args;
133 /* Import the system calls. */
134 static void import(void)
136 #define IMPORT(imp, ret, args) \
137 real_##imp = (ret (*)args)dlsym(RTLD_NEXT, #imp);
142 /*----- Utilities ---------------------------------------------------------*/
144 /* Socket address casts */
145 #define SA(sa) ((struct sockaddr *)(sa))
146 #define SIN(sa) ((struct sockaddr_in *)(sa))
147 #define SUN(sa) ((struct sockaddr_un *)(sa))
150 #define UC(ch) ((unsigned char)(ch))
152 /* Memory allocation */
153 #define NEW(x) ((x) = xmalloc(sizeof(*x)))
154 #define NEWV(x, n) ((x) = xmalloc(sizeof(*x) * (n)))
158 # define D(body) { if (debug) { body } }
163 /* Preservation of error status */
164 #define PRESERVING_ERRNO(body) do { \
165 int _err = errno; { body } errno = _err; \
168 /* Allocate N bytes of memory; abort on failure. */
169 static void *xmalloc(size_t n)
173 if ((p = malloc(n)) == 0) { perror("malloc"); exit(127); }
177 /* Allocate a copy of the null-terminated string P; abort on failure. */
178 static char *xstrdup(const char *p)
180 size_t n = strlen(p) + 1;
181 char *q = xmalloc(n);
186 /*----- Address-type hacking ----------------------------------------------*/
188 /* If M is a simple mask, i.e., consists of a sequence of zero bits followed
189 * by a sequence of one bits, then return the length of the latter sequence
190 * (which may be zero); otherwise return -1.
192 static int simple_mask_length(unsigned long m)
196 while (m & 1) { n++; m >>= 1; }
200 /* Answer whether AF is an interesting address family. */
201 static int family_known_p(int af)
211 /* Return the socket address length for address family AF. */
212 static socklen_t family_socklen(int af)
215 case AF_INET: return (sizeof(struct sockaddr_in));
220 /* Return the width of addresses of kind AF. */
221 static int address_width(int af)
224 case AF_INET: return 32;
229 /* If addresses A and B share a common prefix then return its length;
230 * otherwise return -1.
232 static int common_prefix_length(int af, const ipaddr *a, const ipaddr *b)
236 unsigned long aa = ntohl(a->v4.s_addr), bb = ntohl(b->v4.s_addr);
237 unsigned long m = aa^bb;
238 if ((aa&m) == 0 && (bb&m) == m) return (32 - simple_mask_length(m));
246 /* Extract the port number (in host byte-order) from SA. */
247 static int port_from_sockaddr(const struct sockaddr *sa)
249 switch (sa->sa_family) {
250 case AF_INET: return (ntohs(SIN(sa)->sin_port));
255 /* Store the port number PORT (in host byte-order) in SA. */
256 static void port_to_sockaddr(struct sockaddr *sa, int port)
258 switch (sa->sa_family) {
259 case AF_INET: SIN(sa)->sin_port = htons(port); break;
263 /* Extract the address part from SA and store it in A. */
264 static void ipaddr_from_sockaddr(ipaddr *a, const struct sockaddr *sa)
266 switch (sa->sa_family) {
267 case AF_INET: a->v4 = SIN(sa)->sin_addr; break;
272 /* Copy a whole socket address about. */
273 static void copy_sockaddr(struct sockaddr *sa_dst,
274 const struct sockaddr *sa_src)
275 { memcpy(sa_dst, sa_src, family_socklen(sa_src->sa_family)); }
277 /* Answer whether two addresses are equal. */
278 static int ipaddr_equal_p(int af, const ipaddr *a, const ipaddr *b)
281 case AF_INET: return (a->v4.s_addr == b->v4.s_addr);
286 /* Answer whether the address part of SA is between A and B (inclusive). We
287 * assume that SA has the correct address family.
289 static int sockaddr_in_range_p(const struct sockaddr *sa,
290 const ipaddr *a, const ipaddr *b)
292 switch (sa->sa_family) {
294 unsigned long addr = ntohl(SIN(sa)->sin_addr.s_addr);
295 return (ntohl(a->v4.s_addr) <= addr &&
296 addr <= ntohl(b->v4.s_addr));
303 /* Fill in SA with the appropriate wildcard address. */
304 static void wildcard_address(int af, struct sockaddr *sa)
308 struct sockaddr_in *sin = SIN(sa);
309 memset(sin, 0, sizeof(*sin));
310 sin->sin_family = AF_INET;
312 sin->sin_addr.s_addr = INADDR_ANY;
319 /* Mask the address A, forcing all but the top PLEN bits to zero or one
320 * according to HIGHP.
322 static void mask_address(int af, ipaddr *a, int plen, int highp)
326 unsigned long addr = ntohl(a->v4.s_addr);
327 unsigned long mask = plen ? ~0ul << (32 - plen) : 0;
329 if (highp) addr |= ~mask;
330 a->v4.s_addr = htonl(addr & 0xffffffff);
337 /* Write a presentation form of SA to BUF, a buffer of length SZ. LEN is the
338 * address length; if it's zero, look it up based on the address family.
339 * Return a pointer to the string (which might, in an emergency, be a static
340 * string rather than your buffer).
342 static char *present_sockaddr(const struct sockaddr *sa, socklen_t len,
343 char *buf, size_t sz)
345 #define WANT(n_) do { if (sz < (n_)) goto nospace; } while (0)
346 #define PUTC(c_) do { *buf++ = (c_); sz--; } while (0)
348 if (!sz) return "<no-space-in-buffer>";
349 if (!len) len = family_socklen(sa->sa_family);
351 switch (sa->sa_family) {
353 struct sockaddr_un *sun = SUN(sa);
354 char *p = sun->sun_path;
355 size_t n = len - offsetof(struct sockaddr_un, sun_path);
363 case 0: WANT(2); PUTC('\\'); PUTC('0'); break;
364 case '\a': WANT(2); PUTC('\\'); PUTC('a'); break;
365 case '\n': WANT(2); PUTC('\\'); PUTC('n'); break;
366 case '\r': WANT(2); PUTC('\\'); PUTC('r'); break;
367 case '\t': WANT(2); PUTC('\\'); PUTC('t'); break;
368 case '\v': WANT(2); PUTC('\\'); PUTC('v'); break;
369 case '\\': WANT(2); PUTC('\\'); PUTC('\\'); break;
371 if (*p > ' ' && *p <= '~')
372 { WANT(1); PUTC(*p); }
374 WANT(4); PUTC('\\'); PUTC('x');
375 PUTC((*p >> 4)&0xf); PUTC((*p >> 0)&0xf);
382 if (*p != '/') { WANT(2); PUTC('.'); PUTC('/'); }
383 while (n && *p) { WANT(1); PUTC(*p); p++; n--; }
388 char addrbuf[NI_MAXHOST], portbuf[NI_MAXSERV];
389 int err = getnameinfo(sa, len,
390 addrbuf, sizeof(addrbuf),
391 portbuf, sizeof(portbuf),
392 NI_NUMERICHOST | NI_NUMERICSERV);
394 snprintf(buf, sz, strchr(addrbuf, ':') ? "[%s]:%s" : "%s:%s",
398 snprintf(buf, sz, "<unknown-address-family %d>", sa->sa_family);
408 /* Guess the family of a textual socket address. */
409 static int guess_address_family(const char *p)
410 { return (AF_INET); }
412 /* Parse a socket address P and write the result to SA. */
413 static int parse_sockaddr(struct sockaddr *sa, const char *p)
417 struct addrinfo *ai, ai_hint = { 0 };
419 if (strlen(p) >= sizeof(buf) - 1) return (-1);
420 strcpy(buf, p); p = buf;
422 if ((q = strchr(p, ':')) == 0) return (-1);
426 if ((q = strchr(p, ']')) == 0) return (-1);
428 if (*q != ':') return (-1);
432 ai_hint.ai_family = AF_UNSPEC;
433 ai_hint.ai_socktype = SOCK_DGRAM;
434 ai_hint.ai_flags = AI_NUMERICHOST | AI_NUMERICSERV;
435 if (getaddrinfo(p, q, &ai_hint, &ai)) return (-1);
436 memcpy(sa, ai->ai_addr, ai->ai_addrlen);
441 /*----- Access control lists ----------------------------------------------*/
445 /* Write to standard error a description of the ACL node A. */
446 static void dump_aclnode(aclnode *a)
452 fprintf(stderr, "noip: %c ", a->act ? '+' : '-');
453 plen = common_prefix_length(a->af, &a->minaddr, &a->maxaddr);
454 p = inet_ntop(a->af, &a->minaddr, buf, sizeof(buf));
455 fprintf(stderr, strchr(p, ':') ? "[%s]" : "%s", p);
457 p = inet_ntop(a->af, &a->maxaddr, buf, sizeof(buf));
458 fprintf(stderr, strchr(p, ':') ? "-[%s]" : "-%s", p);
459 } else if (plen < address_width(a->af))
460 fprintf(stderr, "/%d", plen);
461 if (a->minport != 0 || a->maxport != 0xffff) {
462 fprintf(stderr, ":%u", (unsigned)a->minport);
463 if (a->minport != a->maxport)
464 fprintf(stderr, "-%u", (unsigned)a->maxport);
469 static void dump_acl(aclnode *a)
473 for (; a; a = a->next) {
477 fprintf(stderr, "noip: [default policy: %s]\n",
478 act == ALLOW ? "DENY" : "ALLOW");
483 /* Returns nonzero if the ACL A allows the socket address SA. */
484 static int acl_allows_p(aclnode *a, const struct sockaddr *sa)
486 unsigned short port = port_from_sockaddr(sa);
489 D({ char buf[ADDRBUFSZ];
490 fprintf(stderr, "noip: check %s\n",
491 present_sockaddr(sa, 0, buf, sizeof(buf))); })
492 for (; a; a = a->next) {
493 D( dump_aclnode(a); )
494 if (sockaddr_in_range_p(sa, &a->minaddr, &a->maxaddr) &&
495 a->minport <= port && port <= a->maxport) {
496 D( fprintf(stderr, "noip: aha! %s\n", a->act ? "ALLOW" : "DENY"); )
501 D( fprintf(stderr, "noip: nothing found: %s\n", act ? "DENY" : "ALLOW"); )
505 /*----- Socket address conversion -----------------------------------------*/
507 /* Return a uniformly distributed integer between MIN and MAX inclusive. */
508 static unsigned randrange(unsigned min, unsigned max)
512 /* It's so nice not to have to care about the quality of the generator
516 for (mask = 1; mask < max; mask = (mask << 1) | 1)
518 do i = rand() & mask; while (i > max);
522 /* Return the status of Unix-domain socket address SUN. Returns: UNUSED if
523 * the socket doesn't exist; USED if the path refers to an active socket, or
524 * isn't really a socket at all, or we can't tell without a careful search
525 * and QUICKP is set; or STALE if the file refers to a socket which isn't
526 * being used any more.
528 static int unix_socket_status(struct sockaddr_un *sun, int quickp)
536 if (stat(sun->sun_path, &st))
537 return (errno == ENOENT ? UNUSED : USED);
538 if (!S_ISSOCK(st.st_mode) || quickp)
541 if ((fp = fopen("/proc/net/unix", "r")) == 0)
543 if (!fgets(buf, sizeof(buf), fp)) goto done; /* skip header */
544 len = strlen(sun->sun_path);
545 while (fgets(buf, sizeof(buf), fp)) {
547 if (n >= len + 2 && buf[n - len - 2] == ' ' && buf[n - 1] == '\n' &&
548 memcmp(buf + n - len - 1, sun->sun_path, len) == 0)
559 /* Encode the Internet address SA as a Unix-domain address SUN. If WANT is
560 * WANT_FRESH, and SA's port number is zero, then we pick an arbitrary local
561 * port. Otherwise we pick the port given. There's an unpleasant hack to
562 * find servers bound to local wildcard addresses. Returns zero on success;
565 static int encode_inet_addr(struct sockaddr_un *sun,
566 const struct sockaddr *sa,
575 D( fprintf(stderr, "noip: encode %s (%s)",
576 present_sockaddr(sa, 0, buf, sizeof(buf)),
577 want == WANT_EXISTING ? "EXISTING" : "FRESH"); )
578 sun->sun_family = AF_UNIX;
579 if (port_from_sockaddr(sa) || want == WANT_EXISTING) {
580 snprintf(sun->sun_path, sizeof(sun->sun_path), "%s/%s", sockdir,
581 present_sockaddr(sa, 0, buf, sizeof(buf)));
582 rc = unix_socket_status(sun, 0);
583 if (rc == STALE) unlink(sun->sun_path);
584 if (rc != USED && want == WANT_EXISTING) {
585 wildcard_address(sa->sa_family, &addr.sa);
586 port_to_sockaddr(&addr.sa, port_from_sockaddr(sa));
587 snprintf(sun->sun_path, sizeof(sun->sun_path), "%s/%s", sockdir,
588 present_sockaddr(&addr.sa, 0, buf, sizeof(buf)));
589 if (unix_socket_status(sun, 0) == STALE) unlink(sun->sun_path);
592 copy_sockaddr(&addr.sa, sa);
593 for (i = 0; i < 10; i++) {
594 port_to_sockaddr(&addr.sa, randrange(minautoport, maxautoport));
595 snprintf(sun->sun_path, sizeof(sun->sun_path), "%s/%s", sockdir,
596 present_sockaddr(&addr.sa, 0, buf, sizeof(buf)));
597 if (unix_socket_status(sun, 1) == UNUSED) goto found;
599 for (desperatep = 0; desperatep < 2; desperatep++) {
600 for (i = minautoport; i <= maxautoport; i++) {
601 port_to_sockaddr(&addr.sa, i);
602 snprintf(sun->sun_path, sizeof(sun->sun_path), "%s/%s", sockdir,
603 present_sockaddr(&addr.sa, 0, buf, sizeof(buf)));
604 rc = unix_socket_status(sun, !desperatep);
606 case STALE: unlink(sun->sun_path);
607 case UNUSED: goto found;
612 D( fprintf(stderr, " -- can't resolve\n"); )
616 D( fprintf(stderr, " -> `%s'\n", sun->sun_path); )
620 /* Decode the Unix address SUN to an Internet address SIN. If AF_HINT is
621 * nonzero, an empty address (indicative of an unbound Unix-domain socket) of
622 * the is translated to a wildcard Internet address of the appropriate
623 * family. Returns zero on success; -1 on failure (e.g., it wasn't one of
626 static int decode_inet_addr(struct sockaddr *sa, int af_hint,
627 const struct sockaddr_un *sun,
631 size_t n = strlen(sockdir), nn;
634 if (!sa) sa = &addr.sa;
635 if (sun->sun_family != AF_UNIX) return (-1);
636 if (len > sizeof(*sun)) return (-1);
637 ((char *)sun)[len] = 0;
638 nn = strlen(sun->sun_path);
639 D( fprintf(stderr, "noip: decode `%s'", sun->sun_path); )
640 if (af_hint && !sun->sun_path[0]) {
641 wildcard_address(af_hint, sa);
642 D( fprintf(stderr, " -- unbound socket\n"); )
645 if (nn < n + 1 || nn - n >= sizeof(buf) || sun->sun_path[n] != '/' ||
646 memcmp(sun->sun_path, sockdir, n) != 0) {
647 D( fprintf(stderr, " -- not one of ours\n"); )
650 if (parse_sockaddr(sa, sun->sun_path + n + 1)) return (-1);
651 D( fprintf(stderr, " -> %s\n",
652 present_sockaddr(sa, 0, buf, sizeof(buf))); )
656 /* SK is (or at least might be) a Unix-domain socket we created when an
657 * Internet socket was asked for. We've decided it should be an Internet
658 * socket after all, with family AF_HINT, so convert it.
660 static int fixup_real_ip_socket(int sk, int af_hint)
665 struct sockaddr_un sun;
678 _(LINGER, struct linger) \
681 _(RCVTIMEO, struct timeval) \
682 _(SNDTIMEO, struct timeval)
685 if (real_getsockname(sk, SA(&sun), &len))
687 if (decode_inet_addr(&addr.sa, af_hint, &sun, len))
688 return (0); /* Not one of ours */
690 if (real_getsockopt(sk, SOL_SOCKET, SO_TYPE, &type, &len) < 0 ||
691 (nsk = real_socket(addr.sa.sa_family, type, 0)) < 0)
693 #define FIX(opt, ty) do { \
696 if (real_getsockopt(sk, SOL_SOCKET, SO_##opt, &ov_, &len) < 0 || \
697 real_setsockopt(nsk, SOL_SOCKET, SO_##opt, &ov_, len)) { \
704 if ((f = fcntl(sk, F_GETFL)) < 0 ||
705 (fd = fcntl(sk, F_GETFD)) < 0 ||
706 fcntl(nsk, F_SETFL, f) < 0 ||
711 unlink(sun.sun_path);
713 if (fcntl(sk, F_SETFD, fd) < 0) {
714 perror("noip: fixup_real_ip_socket F_SETFD");
720 /* The socket SK is about to be used to communicate with the remote address
721 * SA. Assign it a local address so that getpeername(2) does something
724 static int do_implicit_bind(int sk, const struct sockaddr **sa,
725 socklen_t *len, struct sockaddr_un *sun)
728 socklen_t mylen = sizeof(*sun);
730 if (acl_allows_p(connect_real, *sa)) {
731 if (fixup_real_ip_socket(sk, (*sa)->sa_family)) return (-1);
733 if (real_getsockname(sk, SA(sun), &mylen) < 0) return (-1);
734 if (sun->sun_family == AF_UNIX) {
735 if (mylen < sizeof(*sun)) ((char *)sun)[mylen] = 0;
736 if (!sun->sun_path[0]) {
737 wildcard_address((*sa)->sa_family, &addr.sa);
738 encode_inet_addr(sun, &addr.sa, WANT_FRESH);
739 if (real_bind(sk, SA(sun), SUN_LEN(sun))) return (-1);
741 encode_inet_addr(sun, *sa, WANT_EXISTING);
749 /* We found the real address SA, with length LEN; if it's a Unix-domain
750 * address corresponding to a fake socket, convert it to cover up the
751 * deception. Whatever happens, put the result at FAKE and store its length
754 static void return_fake_name(struct sockaddr *sa, socklen_t len,
755 struct sockaddr *fake, socklen_t *fakelen)
760 if (sa->sa_family == AF_UNIX &&
761 !decode_inet_addr(&addr.sa, 0, SUN(sa), len)) {
763 len = family_socklen(addr.sa.sa_family);
766 if (len > *fakelen) len = *fakelen;
767 if (len > 0) memcpy(fake, sa, len);
771 /*----- Configuration -----------------------------------------------------*/
773 /* Return the process owner's home directory. */
774 static char *home(void)
779 if (getuid() == uid &&
780 (p = getenv("HOME")) != 0)
782 else if ((pw = getpwuid(uid)) != 0)
788 /* Return a good temporary directory to use. */
789 static char *tmpdir(void)
793 if ((p = getenv("TMPDIR")) != 0) return (p);
794 else if ((p = getenv("TMP")) != 0) return (p);
795 else return ("/tmp");
798 /* Return the user's name, or at least something distinctive. */
799 static char *user(void)
805 if ((p = getenv("USER")) != 0) return (p);
806 else if ((p = getenv("LOGNAME")) != 0) return (p);
807 else if ((pw = getpwuid(uid)) != 0) return (pw->pw_name);
809 snprintf(buf, sizeof(buf), "uid-%lu", (unsigned long)uid);
814 /* Skip P over space characters. */
815 #define SKIPSPC do { while (*p && isspace(UC(*p))) p++; } while (0)
817 /* Set Q to point to the next word following P, null-terminate it, and step P
819 #define NEXTWORD(q) do { \
822 while (*p && !isspace(UC(*p))) p++; \
826 /* Set Q to point to the next dotted-quad address, store the ending delimiter
827 * in DEL, null-terminate it, and step P past it. */
828 static void parse_nextaddr(char **pp, char **qq, int *del)
836 p += strcspn(p, "]");
841 while (*p && (*p == '.' || isdigit(UC(*p)))) p++;
848 /* Set Q to point to the next decimal number, store the ending delimiter in
849 * DEL, null-terminate it, and step P past it. */
850 #define NEXTNUMBER(q, del) do { \
853 while (*p && isdigit(UC(*p))) p++; \
858 /* Push the character DEL back so we scan it again, unless it's zero
860 #define RESCAN(del) do { if (del) *--p = del; } while (0)
862 /* Evaluate true if P is pointing to the word KW (and not some longer string
863 * of which KW is a prefix). */
865 #define KWMATCHP(kw) (strncmp(p, kw, sizeof(kw) - 1) == 0 && \
866 !isalnum(UC(p[sizeof(kw) - 1])) && \
867 (p += sizeof(kw) - 1))
869 /* Parse a port list, starting at *PP. Port lists have the form
870 * [:LOW[-HIGH]]: if omitted, all ports are included; if HIGH is omitted,
871 * it's as if HIGH = LOW. Store LOW in *MIN, HIGH in *MAX and set *PP to the
872 * rest of the string.
874 static void parse_ports(char **pp, unsigned short *min, unsigned short *max)
881 { *min = 0; *max = 0xffff; }
884 NEXTNUMBER(q, del); *min = strtoul(q, 0, 0); RESCAN(del);
887 { p++; NEXTNUMBER(q, del); *max = strtoul(q, 0, 0); RESCAN(del); }
894 /* Make a new ACL node. ACT is the verdict; AF is the address family;
895 * MINADDR and MAXADDR are the ranges on IP addresses; MINPORT and MAXPORT
896 * are the ranges on port numbers; TAIL is the list tail to attach the new
899 #define ACLNODE(tail_, act_, \
900 af_, minaddr_, maxaddr_, minport_, maxport_) do { \
905 a_->minaddr = (minaddr_); a_->maxaddr = (maxaddr_); \
906 a_->minport = (minport_); a_->maxport = (maxport_); \
907 *tail_ = a_; tail_ = &a_->next; \
910 /* Parse an ACL line. *PP points to the end of the line; *TAIL points to
911 * the list tail (i.e., the final link in the list). An ACL entry has the
912 * form +|- [any | local | ADDR | ADDR - ADDR | ADDR/ADDR | ADDR/INT] PORTS
913 * where PORTS is parsed by parse_ports above; an ACL line consists of a
914 * comma-separated sequence of entries..
916 static void parse_acl_line(char **pp, aclnode ***tail)
918 ipaddr minaddr, maxaddr;
919 unsigned short minport, maxport;
928 if (*p == '+') act = ALLOW;
929 else if (*p == '-') act = DENY;
934 if (KWMATCHP("any")) {
935 parse_ports(&p, &minport, &maxport);
936 for (i = 0; address_families[i] >= 0; i++) {
937 af = address_families[i];
938 memset(&minaddr, 0, sizeof(minaddr));
939 maxaddr = minaddr; mask_address(af, &maxaddr, 0, 1);
940 ACLNODE(*tail, act, af, minaddr, maxaddr, minport, maxport);
942 } else if (KWMATCHP("local")) {
943 parse_ports(&p, &minport, &maxport);
944 for (i = 0; address_families[i] >= 0; i++) {
945 af = address_families[i];
946 memset(&minaddr, 0, sizeof(minaddr));
947 maxaddr = minaddr; mask_address(af, &maxaddr, 0, 1);
948 ACLNODE(*tail, act, af, minaddr, minaddr, minport, maxport);
949 ACLNODE(*tail, act, af, maxaddr, maxaddr, minport, maxport);
951 for (i = 0; i < n_local_ipaddrs; i++) {
952 ACLNODE(*tail, act, local_ipaddrs[i].af,
953 local_ipaddrs[i].addr, local_ipaddrs[i].addr,
957 parse_nextaddr(&p, &q, &del);
958 af = guess_address_family(q);
959 if (inet_pton(af, q, &minaddr) <= 0) goto bad;
964 parse_nextaddr(&p, &q, &del);
965 if (inet_pton(af, q, &maxaddr) <= 0) goto bad;
967 } else if (*p == '/') {
970 n = strtoul(q, 0, 0);
972 mask_address(af, &minaddr, n, 0);
973 mask_address(af, &maxaddr, n, 1);
976 parse_ports(&p, &minport, &maxport);
977 ACLNODE(*tail, act, af, minaddr, maxaddr, minport, maxport);
980 if (*p != ',') break;
986 D( fprintf(stderr, "noip: bad acl spec (ignored)\n"); )
990 /* Parse the autoports configuration directive. Syntax is MIN - MAX. */
991 static void parse_autoports(char **pp)
998 NEXTNUMBER(q, del); x = strtoul(q, 0, 0); RESCAN(del);
1000 if (*p != '-') goto bad; p++;
1001 NEXTNUMBER(q, del); y = strtoul(q, 0, 0); RESCAN(del);
1002 minautoport = x; maxautoport = y;
1006 D( fprintf(stderr, "bad port range (ignored)\n"); )
1010 /* Parse an ACL from an environment variable VAR, attaching it to the list
1012 static void parse_acl_env(const char *var, aclnode ***tail)
1016 if ((p = getenv(var)) != 0) {
1018 parse_acl_line(&q, tail);
1023 /* Read the configuration from the config file and environment. */
1024 static void readconfig(void)
1031 parse_acl_env("NOIP_REALBIND_BEFORE", &bind_tail);
1032 parse_acl_env("NOIP_REALCONNECT_BEFORE", &connect_tail);
1033 if ((p = getenv("NOIP_AUTOPORTS")) != 0) {
1035 parse_autoports(&q);
1038 if ((p = getenv("NOIP_CONFIG")) == 0)
1039 snprintf(p = buf, sizeof(buf), "%s/.noip", home());
1040 D( fprintf(stderr, "noip: config file: %s\n", p); )
1042 if ((fp = fopen(p, "r")) == 0) {
1043 D( fprintf(stderr, "noip: couldn't read config: %s\n",
1047 while (fgets(buf, sizeof(buf), fp)) {
1052 if (!*p || *p == '#') continue;
1053 while (n && isspace(UC(buf[n - 1]))) n--;
1058 if (strcmp(cmd, "socketdir") == 0)
1059 sockdir = xstrdup(p);
1060 else if (strcmp(cmd, "realbind") == 0)
1061 parse_acl_line(&p, &bind_tail);
1062 else if (strcmp(cmd, "realconnect") == 0)
1063 parse_acl_line(&p, &connect_tail);
1064 else if (strcmp(cmd, "autoports") == 0)
1065 parse_autoports(&p);
1066 else if (strcmp(cmd, "debug") == 0)
1067 debug = *p ? atoi(p) : 1;
1069 D( fprintf(stderr, "noip: bad config command %s\n", cmd); )
1074 parse_acl_env("NOIP_REALBIND", &bind_tail);
1075 parse_acl_env("NOIP_REALCONNECT", &connect_tail);
1076 parse_acl_env("NOIP_REALBIND_AFTER", &bind_tail);
1077 parse_acl_env("NOIP_REALCONNECT_AFTER", &connect_tail);
1080 if (!sockdir) sockdir = getenv("NOIP_SOCKETDIR");
1082 snprintf(buf, sizeof(buf), "%s/noip-%s", tmpdir(), user());
1083 sockdir = xstrdup(buf);
1085 D( fprintf(stderr, "noip: socketdir: %s\n", sockdir);
1086 fprintf(stderr, "noip: autoports: %u-%u\n",
1087 minautoport, maxautoport);
1088 fprintf(stderr, "noip: realbind acl:\n");
1089 dump_acl(bind_real);
1090 fprintf(stderr, "noip: realconnect acl:\n");
1091 dump_acl(connect_real); )
1094 /*----- Overridden system calls -------------------------------------------*/
1096 int socket(int pf, int ty, int proto)
1100 if (!family_known_p(pf)) {
1101 errno = EAFNOSUPPORT;
1110 return (real_socket(pf, ty, proto));
1114 int socketpair(int pf, int ty, int proto, int *sk)
1116 if (pf == PF_INET) {
1120 return (real_socketpair(pf, ty, proto, sk));
1123 int bind(int sk, const struct sockaddr *sa, socklen_t len)
1125 struct sockaddr_un sun;
1127 if (family_known_p(sa->sa_family)) {
1129 if (acl_allows_p(bind_real, sa)) {
1130 if (fixup_real_ip_socket(sk, sa->sa_family))
1133 encode_inet_addr(&sun, sa, WANT_FRESH);
1135 len = SUN_LEN(&sun);
1139 return (real_bind(sk, sa, len));
1142 int connect(int sk, const struct sockaddr *sa, socklen_t len)
1144 struct sockaddr_un sun;
1147 if (!family_known_p(sa->sa_family))
1148 rc = real_connect(sk, sa, len);
1151 do_implicit_bind(sk, &sa, &len, &sun);
1153 rc = real_connect(sk, sa, len);
1156 case ENOENT: errno = ECONNREFUSED; break;
1163 ssize_t sendto(int sk, const void *buf, size_t len, int flags,
1164 const struct sockaddr *to, socklen_t tolen)
1166 struct sockaddr_un sun;
1168 if (to && to->sa_family == AF_INET) {
1170 do_implicit_bind(sk, &to, &tolen, &sun);
1173 return (real_sendto(sk, buf, len, flags, to, tolen));
1176 ssize_t recvfrom(int sk, void *buf, size_t len, int flags,
1177 struct sockaddr *from, socklen_t *fromlen)
1180 socklen_t mylen = sizeof(sabuf);
1184 return real_recvfrom(sk, buf, len, flags, 0, 0);
1186 n = real_recvfrom(sk, buf, len, flags, SA(sabuf), &mylen);
1189 return_fake_name(SA(sabuf), mylen, from, fromlen);
1194 ssize_t sendmsg(int sk, const struct msghdr *msg, int flags)
1196 struct sockaddr_un sun;
1197 const struct sockaddr *sa;
1198 struct msghdr mymsg;
1200 if (msg->msg_name && SA(msg->msg_name)->sa_family == AF_INET) {
1202 sa = SA(msg->msg_name);
1204 do_implicit_bind(sk, &sa, &mymsg.msg_namelen, &sun);
1205 mymsg.msg_name = SA(sa);
1209 return (real_sendmsg(sk, msg, flags));
1212 ssize_t recvmsg(int sk, struct msghdr *msg, int flags)
1215 struct sockaddr *sa;
1220 return (real_recvmsg(sk, msg, flags));
1222 sa = SA(msg->msg_name);
1223 len = msg->msg_namelen;
1224 msg->msg_name = sabuf;
1225 msg->msg_namelen = sizeof(sabuf);
1226 n = real_recvmsg(sk, msg, flags);
1229 return_fake_name(SA(sabuf), msg->msg_namelen, sa, &len);
1231 msg->msg_namelen = len;
1236 int accept(int sk, struct sockaddr *sa, socklen_t *len)
1239 socklen_t mylen = sizeof(sabuf);
1240 int nsk = real_accept(sk, SA(sabuf), &mylen);
1244 return_fake_name(SA(sabuf), mylen, sa, len);
1248 int getsockname(int sk, struct sockaddr *sa, socklen_t *len)
1252 socklen_t mylen = sizeof(sabuf);
1253 if (real_getsockname(sk, SA(sabuf), &mylen))
1255 return_fake_name(SA(sabuf), mylen, sa, len);
1260 int getpeername(int sk, struct sockaddr *sa, socklen_t *len)
1264 socklen_t mylen = sizeof(sabuf);
1265 if (real_getpeername(sk, SA(sabuf), &mylen))
1267 return_fake_name(SA(sabuf), mylen, sa, len);
1272 int getsockopt(int sk, int lev, int opt, void *p, socklen_t *len)
1282 return (real_getsockopt(sk, lev, opt, p, len));
1285 int setsockopt(int sk, int lev, int opt, const void *p, socklen_t len)
1294 case SO_BINDTODEVICE:
1295 case SO_ATTACH_FILTER:
1296 case SO_DETACH_FILTER:
1299 return (real_setsockopt(sk, lev, opt, p, len));
1302 /*----- Initialization ----------------------------------------------------*/
1304 /* Clean up the socket directory, deleting stale sockets. */
1305 static void cleanup_sockdir(void)
1310 struct sockaddr_un sun;
1313 if ((dir = opendir(sockdir)) == 0) return;
1314 sun.sun_family = AF_UNIX;
1315 while ((d = readdir(dir)) != 0) {
1316 if (d->d_name[0] == '.') continue;
1317 snprintf(sun.sun_path, sizeof(sun.sun_path),
1318 "%s/%s", sockdir, d->d_name);
1319 if (decode_inet_addr(&addr.sa, 0, &sun, SUN_LEN(&sun)) ||
1320 stat(sun.sun_path, &st) ||
1321 !S_ISSOCK(st.st_mode)) {
1322 D( fprintf(stderr, "noip: ignoring unknown socketdir entry `%s'\n",
1326 if (unix_socket_status(&sun, 0) == STALE) {
1327 D( fprintf(stderr, "noip: clearing away stale socket %s\n",
1329 unlink(sun.sun_path);
1335 /* Find the addresses attached to local network interfaces, and remember them
1338 static void get_local_ipaddrs(void)
1340 struct ifaddrs *ifa_head, *ifa;
1344 if (getifaddrs(&ifa_head)) { perror("getifaddrs"); return; }
1345 for (n_local_ipaddrs = 0, ifa = ifa_head;
1346 n_local_ipaddrs < MAX_LOCAL_IPADDRS && ifa;
1347 ifa = ifa->ifa_next) {
1348 if (!ifa->ifa_addr || !family_known_p(ifa->ifa_addr->sa_family))
1350 ipaddr_from_sockaddr(&a, ifa->ifa_addr);
1351 D({ char buf[ADDRBUFSZ];
1352 fprintf(stderr, "noip: local addr %s = %s", ifa->ifa_name,
1353 inet_ntop(ifa->ifa_addr->sa_family, &a,
1354 buf, sizeof(buf))); })
1355 for (i = 0; i < n_local_ipaddrs; i++) {
1356 if (ifa->ifa_addr->sa_family == local_ipaddrs[i].af &&
1357 ipaddr_equal_p(local_ipaddrs[i].af, &a, &local_ipaddrs[i].addr)) {
1358 D( fprintf(stderr, " (duplicate)\n"); )
1362 D( fprintf(stderr, "\n"); )
1363 local_ipaddrs[n_local_ipaddrs].af = ifa->ifa_addr->sa_family;
1364 local_ipaddrs[n_local_ipaddrs].addr = a;
1368 freeifaddrs(ifa_head);
1371 /* Print the given message to standard error. Avoids stdio. */
1372 static void printerr(const char *p)
1373 { if (write(STDERR_FILENO, p, strlen(p))) ; }
1375 /* Create the socket directory, being careful about permissions. */
1376 static void create_sockdir(void)
1380 if (stat(sockdir, &st)) {
1381 if (errno == ENOENT) {
1382 if (mkdir(sockdir, 0700)) {
1383 perror("noip: creating socketdir");
1386 if (!stat(sockdir, &st))
1389 perror("noip: checking socketdir");
1393 if (!S_ISDIR(st.st_mode)) {
1394 printerr("noip: bad socketdir: not a directory\n");
1397 if (st.st_uid != uid) {
1398 printerr("noip: bad socketdir: not owner\n");
1401 if (st.st_mode & 077) {
1402 printerr("noip: bad socketdir: not private\n");
1407 /* Initialization function. */
1408 static void setup(void) __attribute__((constructor));
1409 static void setup(void)
1416 if ((p = getenv("NOIP_DEBUG")) && atoi(p))
1418 get_local_ipaddrs();
1425 /*----- That's all, folks -------------------------------------------------*/