X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~mdw/git/preload-hacks/blobdiff_plain/2a06ea0b5d53bb50a03818c3da598764009469dc..9111857cc67644ff89749d5919647b38033bb6fd:/noip.c diff --git a/noip.c b/noip.c index 9c5cd68..345f325 100644 --- a/noip.c +++ b/noip.c @@ -34,6 +34,7 @@ #include #include #include +#include #include #include #include @@ -56,10 +57,19 @@ #include #include +#ifndef SUN_LEN +# define SUN_LEN (sun) \ + (strlen((sun)->sun_path) + offsetof(struct sockaddr_un, sun_path)) +#endif + /*----- Data structures ---------------------------------------------------*/ -enum { UNUSED, STALE, USED }; /* Unix socket status values */ -enum { WANT_FRESH, WANT_EXISTING }; /* Socket address dispositions */ +/* Unix socket status values. */ +#define UNUSED 0u /* No sign of anyone using it */ +#define STALE 1u /* Socket exists, but is abandoned */ +#define USED 16u /* Socket is in active use */ +#define LISTEN 2u /* Socket has an active listener */ + enum { DENY, ALLOW }; /* ACL verdicts */ static int address_families[] = { AF_INET, AF_INET6, -1 }; @@ -88,6 +98,23 @@ typedef struct aclnode { unsigned short minport, maxport; } aclnode; +/* Implicit bind records */ +typedef struct impbind { + struct impbind *next; + int af, how; + ipaddr minaddr, maxaddr, bindaddr; +} impbind; +enum { EXPLICIT, SAME }; + +/* A type for an address range */ +typedef struct addrrange { + int type; + union { + struct { int af; ipaddr min, max; } range; + } u; +} addrrange; +enum { EMPTY, ANY, LOCAL, RANGE }; + /* Local address records */ typedef struct full_ipaddr { int af; @@ -106,6 +133,7 @@ static unsigned minautoport = 16384, maxautoport = 65536; /* Access control lists */ static aclnode *bind_real, **bind_tail = &bind_real; static aclnode *connect_real, **connect_tail = &connect_real; +static impbind *impbinds, **impbind_tail = &impbinds; /*----- Import the real versions of functions -----------------------------*/ @@ -125,7 +153,8 @@ static aclnode *connect_real, **connect_tail = &connect_real; _(recvfrom, ssize_t, (int, void *buf, size_t, int, \ struct sockaddr *from, socklen_t *fromlen)) \ _(sendmsg, ssize_t, (int, const struct msghdr *, int)) \ - _(recvmsg, ssize_t, (int, struct msghdr *, int)) + _(recvmsg, ssize_t, (int, struct msghdr *, int)) \ + _(ioctl, int, (int, unsigned long, ...)) /* Function pointers to set up. */ #define DECL(imp, ret, args) static ret (*real_##imp) args; @@ -159,8 +188,10 @@ static void import(void) /* Debugging */ #ifdef DEBUG # define D(body) { if (debug) { body } } +# define Dpid pid_t pid = debug ? getpid() : -1 #else # define D(body) ; +# define Dpid #endif /* Preservation of error status */ @@ -285,6 +316,7 @@ static void port_to_sockaddr(struct sockaddr *sa, int port) default: abort(); } } + /* Extract the address part from SA and store it in A. */ static void ipaddr_from_sockaddr(ipaddr *a, const struct sockaddr *sa) { @@ -295,11 +327,65 @@ static void ipaddr_from_sockaddr(ipaddr *a, const struct sockaddr *sa) } } +/* Store the address A in SA. */ +static void ipaddr_to_sockaddr(struct sockaddr *sa, const ipaddr *a) +{ + switch (sa->sa_family) { + case AF_INET: + SIN(sa)->sin_addr = a->v4; + break; + case AF_INET6: + SIN6(sa)->sin6_addr = a->v6; + SIN6(sa)->sin6_scope_id = 0; + SIN6(sa)->sin6_flowinfo = 0; + break; + default: + abort(); + } +} + /* Copy a whole socket address about. */ static void copy_sockaddr(struct sockaddr *sa_dst, const struct sockaddr *sa_src) { memcpy(sa_dst, sa_src, family_socklen(sa_src->sa_family)); } +/* Convert an AF_INET socket address into the equivalent IPv4-mapped AF_INET6 + * address. + */ +static void map_ipv4_sockaddr(struct sockaddr_in6 *a6, + const struct sockaddr_in *a4) +{ + size_t i; + in_addr_t a = ntohl(a4->sin_addr.s_addr); + + a6->sin6_family = AF_INET6; + a6->sin6_port = a4->sin_port; + a6->sin6_scope_id = 0; + a6->sin6_flowinfo = 0; + for (i = 0; i < 10; i++) a6->sin6_addr.s6_addr[i] = 0; + for (i = 10; i < 12; i++) a6->sin6_addr.s6_addr[i] = 0xff; + for (i = 0; i < 4; i++) a6->sin6_addr.s6_addr[15 - i] = (a >> 8*i)&0xff; +} + +/* Convert an AF_INET6 socket address containing an IPv4-mapped IPv6 address + * into the equivalent AF_INET4 address. Return zero on success, or -1 if + * the address has the wrong form. + */ +static int unmap_ipv4_sockaddr(struct sockaddr_in *a4, + const struct sockaddr_in6 *a6) +{ + size_t i; + in_addr_t a; + + for (i = 0; i < 10; i++) if (a6->sin6_addr.s6_addr[i] != 0) return (-1); + for (i = 10; i < 12; i++) if (a6->sin6_addr.s6_addr[i] != 0xff) return (-1); + for (i = 0, a = 0; i < 4; i++) a |= a6->sin6_addr.s6_addr[15 - i] << 8*i; + a4->sin_family = AF_INET; + a4->sin_port = a6->sin6_port; + a4->sin_addr.s_addr = htonl(a); + return (0); +} + /* Answer whether two addresses are equal. */ static int ipaddr_equal_p(int af, const ipaddr *a, const ipaddr *b) { @@ -353,7 +439,7 @@ static void wildcard_address(int af, struct sockaddr *sa) } break; case AF_INET6: { struct sockaddr_in6 *sin6 = SIN6(sa); - memset(sin6, 0, sizeof(sin6)); + memset(sin6, 0, sizeof(*sin6)); sin6->sin6_family = AF_INET6; sin6->sin6_port = 0; sin6->sin6_addr = in6addr_any; @@ -404,6 +490,7 @@ static char *present_sockaddr(const struct sockaddr *sa, socklen_t len, #define WANT(n_) do { if (sz < (n_)) goto nospace; } while (0) #define PUTC(c_) do { *buf++ = (c_); sz--; } while (0) + if (!sa) return ""; if (!sz) return ""; if (!len) len = family_socklen(sa->sa_family); @@ -501,22 +588,27 @@ static int parse_sockaddr(struct sockaddr *sa, const char *p) #ifdef DEBUG -/* Write to standard error a description of the ACL node A. */ -static void dump_aclnode(aclnode *a) +static void dump_addrrange(int af, const ipaddr *min, const ipaddr *max) { char buf[ADDRBUFSZ]; const char *p; int plen; - fprintf(stderr, "noip: %c ", a->act ? '+' : '-'); - plen = common_prefix_length(a->af, &a->minaddr, &a->maxaddr); - p = inet_ntop(a->af, &a->minaddr, buf, sizeof(buf)); + plen = common_prefix_length(af, min, max); + p = inet_ntop(af, min, buf, sizeof(buf)); fprintf(stderr, strchr(p, ':') ? "[%s]" : "%s", p); if (plen < 0) { - p = inet_ntop(a->af, &a->maxaddr, buf, sizeof(buf)); + p = inet_ntop(af, &max, buf, sizeof(buf)); fprintf(stderr, strchr(p, ':') ? "-[%s]" : "-%s", p); - } else if (plen < address_width(a->af)) + } else if (plen < address_width(af)) fprintf(stderr, "/%d", plen); +} + +/* Write to standard error a description of the ACL node A. */ +static void dump_aclnode(const aclnode *a) +{ + fprintf(stderr, "noip(%d): %c ", getpid(), a->act ? '+' : '-'); + dump_addrrange(a->af, &a->minaddr, &a->maxaddr); if (a->minport != 0 || a->maxport != 0xffff) { fprintf(stderr, ":%u", (unsigned)a->minport); if (a->minport != a->maxport) @@ -525,7 +617,7 @@ static void dump_aclnode(aclnode *a) fputc('\n', stderr); } -static void dump_acl(aclnode *a) +static void dump_acl(const aclnode *a) { int act = ALLOW; @@ -533,31 +625,35 @@ static void dump_acl(aclnode *a) dump_aclnode(a); act = a->act; } - fprintf(stderr, "noip: [default policy: %s]\n", + fprintf(stderr, "noip(%d): [default policy: %s]\n", getpid(), act == ALLOW ? "DENY" : "ALLOW"); } #endif /* Returns nonzero if the ACL A allows the socket address SA. */ -static int acl_allows_p(aclnode *a, const struct sockaddr *sa) +static int acl_allows_p(const aclnode *a, const struct sockaddr *sa) { unsigned short port = port_from_sockaddr(sa); int act = ALLOW; + Dpid; D({ char buf[ADDRBUFSZ]; - fprintf(stderr, "noip: check %s\n", + fprintf(stderr, "noip(%d): check %s\n", pid, present_sockaddr(sa, 0, buf, sizeof(buf))); }) for (; a; a = a->next) { D( dump_aclnode(a); ) - if (sockaddr_in_range_p(sa, &a->minaddr, &a->maxaddr) && + if (a->af == sa->sa_family && + sockaddr_in_range_p(sa, &a->minaddr, &a->maxaddr) && a->minport <= port && port <= a->maxport) { - D( fprintf(stderr, "noip: aha! %s\n", a->act ? "ALLOW" : "DENY"); ) + D( fprintf(stderr, "noip(%d): aha! %s\n", pid, + a->act ? "ALLOW" : "DENY"); ) return (a->act); } act = a->act; } - D( fprintf(stderr, "noip: nothing found: %s\n", act ? "DENY" : "ALLOW"); ) + D( fprintf(stderr, "noip(%d): nothing found: %s\n", pid, + act ? "DENY" : "ALLOW"); ) return (!act); } @@ -590,97 +686,234 @@ static int unix_socket_status(struct sockaddr_un *sun, int quickp) FILE *fp = 0; size_t len, n; int rc; + unsigned long f; char buf[256]; + /* If we can't find the socket node, then it's definitely not in use. If + * we get some other error, then this socket is weird. + */ if (stat(sun->sun_path, &st)) return (errno == ENOENT ? UNUSED : USED); + + /* If it's not a socket, then something weird is going on. If we're just + * probing quickly to find a spare port, then existence is sufficient to + * discourage us now. + */ if (!S_ISSOCK(st.st_mode) || quickp) return (USED); + + /* The socket's definitely there, but is anyone actually still holding it + * open? The only way I know to discover this is to trundle through + * `/proc/net/unix'. If there's no entry, then the socket must be stale. + */ rc = USED; if ((fp = fopen("/proc/net/unix", "r")) == 0) goto done; if (!fgets(buf, sizeof(buf), fp)) goto done; /* skip header */ len = strlen(sun->sun_path); + rc = 0; while (fgets(buf, sizeof(buf), fp)) { n = strlen(buf); if (n >= len + 2 && buf[n - len - 2] == ' ' && buf[n - 1] == '\n' && - memcmp(buf + n - len - 1, sun->sun_path, len) == 0) - goto done; + memcmp(buf + n - len - 1, sun->sun_path, len) == 0) { + rc |= USED; + if (sscanf(buf, "%*s %*x %*x %lx", &f) < 0 || (f&0x00010000)) + rc |= LISTEN; + } } if (ferror(fp)) goto done; - rc = STALE; + if (!rc) rc = STALE; done: if (fp) fclose(fp); + + /* All done. */ + return (rc); +} + +/* Encode SA as a Unix-domain address SUN, and return whether it's currently + * in use. + */ +static int encode_single_inet_addr(const struct sockaddr *sa, + struct sockaddr_un *sun, + int quickp) +{ + char buf[ADDRBUFSZ]; + int rc; + + snprintf(sun->sun_path, sizeof(sun->sun_path), "%s/%s", sockdir, + present_sockaddr(sa, 0, buf, sizeof(buf))); + rc = unix_socket_status(sun, quickp); + if (rc == STALE) unlink(sun->sun_path); return (rc); } -/* Encode the Internet address SA as a Unix-domain address SUN. If WANT is - * WANT_FRESH, and SA's port number is zero, then we pick an arbitrary local - * port. Otherwise we pick the port given. There's an unpleasant hack to - * find servers bound to local wildcard addresses. Returns zero on success; - * -1 on failure. +/* Convert the IP address SA to a Unix-domain address SUN. Fail if the + * address seems already taken. If DESPARATEP then try cleaning up stale old + * sockets. + */ +static int encode_unused_inet_addr(struct sockaddr *sa, + struct sockaddr_un *sun, + int desperatep) +{ + address waddr, maddr; + struct sockaddr_un wsun; + int port = port_from_sockaddr(sa); + + /* First, look for an exact match. Only look quickly unless we're + * desperate. If the socket is in use, we fail here. (This could get + * racy. Let's not worry about that for now.) + */ + if (encode_single_inet_addr(sa, sun, !desperatep)&USED) + return (-1); + + /* Next, check the corresponding wildcard address, so as to avoid + * inadvertant collisions with listeners. Do this in the same way. + */ + wildcard_address(sa->sa_family, &waddr.sa); + port_to_sockaddr(&waddr.sa, port); + if (encode_single_inet_addr(&waddr.sa, &wsun, !desperatep)&USED) + return (-1); + + /* We're not done yet. If this is an IPv4 address, then /also/ check (a) + * the v6-mapped version, (b) the v6-mapped v4 wildcard, /and/ (c) the v6 + * wildcard. Ugh! + */ + if (sa->sa_family == AF_INET) { + map_ipv4_sockaddr(&maddr.sin6, SIN(&sa)); + if (encode_single_inet_addr(&maddr.sa, &wsun, !desperatep)&USED) + return (-1); + + map_ipv4_sockaddr(&maddr.sin6, &waddr.sin); + if (encode_single_inet_addr(&maddr.sa, &wsun, !desperatep)&USED) + return (-1); + + wildcard_address(AF_INET6, &waddr.sa); + port_to_sockaddr(&waddr.sa, port); + if (encode_single_inet_addr(&waddr.sa, &wsun, !desperatep)&USED) + return (-1); + } + + /* All is well. */ + return (0); +} + +/* Encode the Internet address SA as a Unix-domain address SUN. If the flag + * `ENCF_FRESH' is set, and SA's port number is zero, then we pick an + * arbitrary local port. Otherwise we pick the port given. There's an + * unpleasant hack to find servers bound to local wildcard addresses. + * Returns zero on success; -1 on failure. */ +#define ENCF_FRESH 1u +#define ENCF_REUSEADDR 2u static int encode_inet_addr(struct sockaddr_un *sun, const struct sockaddr *sa, - int want) + unsigned f) { int i; int desperatep = 0; address addr; - char buf[ADDRBUFSZ]; + struct sockaddr_in6 sin6; + int port = port_from_sockaddr(sa); int rc; + char buf[ADDRBUFSZ]; - D( fprintf(stderr, "noip: encode %s (%s)", + D( fprintf(stderr, "noip(%d): encode %s (%s)", getpid(), present_sockaddr(sa, 0, buf, sizeof(buf)), - want == WANT_EXISTING ? "EXISTING" : "FRESH"); ) + (f&ENCF_FRESH) ? "FRESH" : "EXISTING"); ) + + /* Start making the Unix-domain address. */ sun->sun_family = AF_UNIX; - if (port_from_sockaddr(sa) || want == WANT_EXISTING) { - snprintf(sun->sun_path, sizeof(sun->sun_path), "%s/%s", sockdir, - present_sockaddr(sa, 0, buf, sizeof(buf))); - rc = unix_socket_status(sun, 0); - if (rc == STALE) unlink(sun->sun_path); - if (rc != USED && want == WANT_EXISTING) { - wildcard_address(sa->sa_family, &addr.sa); - port_to_sockaddr(&addr.sa, port_from_sockaddr(sa)); - snprintf(sun->sun_path, sizeof(sun->sun_path), "%s/%s", sockdir, - present_sockaddr(&addr.sa, 0, buf, sizeof(buf))); - if (unix_socket_status(sun, 0) == STALE) unlink(sun->sun_path); + + if (port || !(f&ENCF_FRESH)) { + + /* Try the address as given. If it's in use, or we don't necessarily + * want an existing socket, then we're done. + */ + rc = encode_single_inet_addr(sa, sun, 0); + if ((f&ENCF_REUSEADDR) && !(rc&LISTEN)) unlink(sun->sun_path); + if ((rc&USED) || (f&ENCF_FRESH)) goto found; + + /* We're looking for a socket which already exists. This is + * unfortunately difficult, because we must deal both with wildcards and + * v6-mapped IPv4 addresses. + * + * * We've just tried searching for a socket whose name is an exact + * match for our remote address. If the remote address is IPv4, then + * we should try again with the v6-mapped equivalent. + * + * * Failing that, we try again with the wildcard address for the + * appropriate address family. + * + * * Failing /that/, if the remote address is IPv4, then we try + * /again/, increasingly desperately, first with the v6-mapped IPv4 + * wildcard address, and then with the IPv6 wildcard address. This + * will cause magic v6-mapping to occur when the connection is + * accepted, which we hope won't cause too much trouble. + */ + + if (sa->sa_family == AF_INET) { + map_ipv4_sockaddr(&addr.sin6, SIN(sa)); + if (encode_single_inet_addr(&addr.sa, sun, 0)&USED) goto found; } + + wildcard_address(sa->sa_family, &addr.sa); + port_to_sockaddr(&addr.sa, port); + if (encode_single_inet_addr(&addr.sa, sun, 0)&USED) goto found; + + if (sa->sa_family == AF_INET) { + map_ipv4_sockaddr(&sin6, &addr.sin); + if (encode_single_inet_addr(SA(&sin6), sun, 0)&USED) goto found; + wildcard_address(AF_INET6, &addr.sa); + port_to_sockaddr(&addr.sa, port); + if (encode_single_inet_addr(&addr.sa, sun, 0)&USED) goto found; + } + + /* Well, this isn't going to work (unless a miraculous race is lost), but + * we might as well try. + */ + encode_single_inet_addr(sa, sun, 1); + } else { + /* We want a fresh new socket. */ + + /* Make a copy of the given address, because we're going to mangle it. */ copy_sockaddr(&addr.sa, sa); + + /* Try a few random-ish port numbers to see if any of them is spare. */ for (i = 0; i < 10; i++) { port_to_sockaddr(&addr.sa, randrange(minautoport, maxautoport)); - snprintf(sun->sun_path, sizeof(sun->sun_path), "%s/%s", sockdir, - present_sockaddr(&addr.sa, 0, buf, sizeof(buf))); - if (unix_socket_status(sun, 1) == UNUSED) goto found; + if (!encode_unused_inet_addr(&addr.sa, sun, 0)) goto found; } + + /* Things must be getting tight. Work through all of the autoport range + * to see if we can find a spare one. The first time, just do it the + * quick way; if that doesn't work, then check harder for stale sockets. + */ for (desperatep = 0; desperatep < 2; desperatep++) { for (i = minautoport; i <= maxautoport; i++) { port_to_sockaddr(&addr.sa, i); - snprintf(sun->sun_path, sizeof(sun->sun_path), "%s/%s", sockdir, - present_sockaddr(&addr.sa, 0, buf, sizeof(buf))); - rc = unix_socket_status(sun, !desperatep); - switch (rc) { - case STALE: unlink(sun->sun_path); - case UNUSED: goto found; - } + if (!encode_unused_inet_addr(&addr.sa, sun, 0)) goto found; } } + + /* We failed to find any free ports. */ errno = EADDRINUSE; D( fprintf(stderr, " -- can't resolve\n"); ) return (-1); - found:; } + + /* Success. */ +found: D( fprintf(stderr, " -> `%s'\n", sun->sun_path); ) return (0); } /* Decode the Unix address SUN to an Internet address SIN. If AF_HINT is - * nonzero, an empty address (indicative of an unbound Unix-domain socket) of - * the is translated to a wildcard Internet address of the appropriate - * family. Returns zero on success; -1 on failure (e.g., it wasn't one of - * our addresses). + * nonzero, an empty address (indicative of an unbound Unix-domain socket) is + * translated to a wildcard Internet address of the appropriate family. + * Returns zero on success; -1 on failure (e.g., it wasn't one of our + * addresses). */ static int decode_inet_addr(struct sockaddr *sa, int af_hint, const struct sockaddr_un *sun, @@ -695,7 +928,7 @@ static int decode_inet_addr(struct sockaddr *sa, int af_hint, if (len > sizeof(*sun)) return (-1); ((char *)sun)[len] = 0; nn = strlen(sun->sun_path); - D( fprintf(stderr, "noip: decode `%s'", sun->sun_path); ) + D( fprintf(stderr, "noip(%d): decode `%s'", getpid(), sun->sun_path); ) if (af_hint && !sun->sun_path[0]) { wildcard_address(af_hint, sa); D( fprintf(stderr, " -- unbound socket\n"); ) @@ -714,9 +947,11 @@ static int decode_inet_addr(struct sockaddr *sa, int af_hint, /* SK is (or at least might be) a Unix-domain socket we created when an * Internet socket was asked for. We've decided it should be an Internet - * socket after all, with family AF_HINT, so convert it. + * socket after all, with family AF_HINT, so convert it. If TMP is not null, + * then don't replace the existing descriptor: store the new socket in *TMP + * and return zero. */ -static int fixup_real_ip_socket(int sk, int af_hint) +static int fixup_real_ip_socket(int sk, int af_hint, int *tmp) { int nsk; int type; @@ -760,46 +995,21 @@ static int fixup_real_ip_socket(int sk, int af_hint) } while (0); OPTS(FIX) #undef FIX - if ((f = fcntl(sk, F_GETFL)) < 0 || - (fd = fcntl(sk, F_GETFD)) < 0 || - fcntl(nsk, F_SETFL, f) < 0 || - dup2(nsk, sk) < 0) { + if (tmp) + *tmp = nsk; + else { + if ((f = fcntl(sk, F_GETFL)) < 0 || + (fd = fcntl(sk, F_GETFD)) < 0 || + fcntl(nsk, F_SETFL, f) < 0 || + dup2(nsk, sk) < 0) { + close(nsk); + return (-1); + } + unlink(sun.sun_path); close(nsk); - return (-1); - } - unlink(sun.sun_path); - close(nsk); - if (fcntl(sk, F_SETFD, fd) < 0) { - perror("noip: fixup_real_ip_socket F_SETFD"); - abort(); - } - return (0); -} - -/* The socket SK is about to be used to communicate with the remote address - * SA. Assign it a local address so that getpeername(2) does something - * useful. - */ -static int do_implicit_bind(int sk, const struct sockaddr **sa, - socklen_t *len, struct sockaddr_un *sun) -{ - address addr; - socklen_t mylen = sizeof(*sun); - - if (acl_allows_p(connect_real, *sa)) { - if (fixup_real_ip_socket(sk, (*sa)->sa_family)) return (-1); - } else { - if (real_getsockname(sk, SA(sun), &mylen) < 0) return (-1); - if (sun->sun_family == AF_UNIX) { - if (mylen < sizeof(*sun)) ((char *)sun)[mylen] = 0; - if (!sun->sun_path[0]) { - wildcard_address((*sa)->sa_family, &addr.sa); - encode_inet_addr(sun, &addr.sa, WANT_FRESH); - if (real_bind(sk, SA(sun), SUN_LEN(sun))) return (-1); - } - encode_inet_addr(sun, *sa, WANT_EXISTING); - *sa = SA(sun); - *len = SUN_LEN(sun); + if (fcntl(sk, F_SETFD, fd) < 0) { + perror("noip: fixup_real_ip_socket F_SETFD"); + abort(); } } return (0); @@ -810,16 +1020,25 @@ static int do_implicit_bind(int sk, const struct sockaddr **sa, * deception. Whatever happens, put the result at FAKE and store its length * at FAKELEN. */ +#define FNF_V6MAPPED 1u static void return_fake_name(struct sockaddr *sa, socklen_t len, - struct sockaddr *fake, socklen_t *fakelen) + struct sockaddr *fake, socklen_t *fakelen, + unsigned f) { address addr; + struct sockaddr_in6 sin6; socklen_t alen; if (sa->sa_family == AF_UNIX && !decode_inet_addr(&addr.sa, 0, SUN(sa), len)) { - sa = &addr.sa; - len = family_socklen(addr.sa.sa_family); + if (addr.sa.sa_family != AF_INET || !(f&FNF_V6MAPPED)) { + sa = &addr.sa; + len = family_socklen(addr.sa.sa_family); + } else { + map_ipv4_sockaddr(&sin6, &addr.sin); + sa = SA(&sin6); + len = family_socklen(AF_INET6); + } } alen = len; if (len > *fakelen) len = *fakelen; @@ -827,6 +1046,156 @@ static void return_fake_name(struct sockaddr *sa, socklen_t len, *fakelen = alen; } +/* Variant of `return_fake_name' above, specifically handling the weirdness + * of remote v6-mapped IPv4 addresses. If SK's fake local address is IPv6, + * and the remote address is IPv4, then return a v6-mapped version of the + * remote address. + */ +static void return_fake_peer(int sk, struct sockaddr *sa, socklen_t len, + struct sockaddr *fake, socklen_t *fakelen) +{ + char sabuf[1024]; + socklen_t mylen = sizeof(sabuf); + unsigned fnf = 0; + address addr; + int rc; + + PRESERVING_ERRNO({ + rc = real_getsockname(sk, SA(sabuf), &mylen); + if (!rc && sa->sa_family == AF_UNIX && + !decode_inet_addr(&addr.sa, 0, SUN(sabuf), mylen) && + addr.sa.sa_family == AF_INET6) + fnf |= FNF_V6MAPPED; + }); + return_fake_name(sa, len, fake, fakelen, fnf); +} + +/*----- Implicit binding --------------------------------------------------*/ + +#ifdef DEBUG + +static void dump_impbind(const impbind *i) +{ + char buf[ADDRBUFSZ]; + + fprintf(stderr, "noip(%d): ", getpid()); + dump_addrrange(i->af, &i->minaddr, &i->maxaddr); + switch (i->how) { + case SAME: fprintf(stderr, " "); break; + case EXPLICIT: + fprintf(stderr, " %s", inet_ntop(i->af, &i->bindaddr, + buf, sizeof(buf))); + break; + default: abort(); + } + fputc('\n', stderr); +} + +static void dump_impbind_list(void) +{ + const impbind *i; + + for (i = impbinds; i; i = i->next) dump_impbind(i); +} + +#endif + +/* The socket SK is about to be used to communicate with the remote address + * SA. Assign it a local address so that getpeername(2) does something + * useful. + * + * If the flag `IBF_V6MAPPED' is set then, then SA must be an `AF_INET' + * address; after deciding on the appropriate local address, convert it to be + * an IPv4-mapped IPv6 address before final conversion to a Unix-domain + * socket address and actually binding. Note that this could well mean that + * the socket ends up bound to the v6-mapped v4 wildcard address + * ::ffff:0.0.0.0, which looks very strange but is meaningful. + */ +#define IBF_V6MAPPED 1u +static int do_implicit_bind(int sk, const struct sockaddr *sa, unsigned f) +{ + address addr; + struct sockaddr_in6 sin6; + struct sockaddr_un sun; + const impbind *i; + Dpid; + + D( fprintf(stderr, "noip(%d): checking impbind list...\n", pid); ) + for (i = impbinds; i; i = i->next) { + D( dump_impbind(i); ) + if (sa->sa_family == i->af && + sockaddr_in_range_p(sa, &i->minaddr, &i->maxaddr)) { + D( fprintf(stderr, "noip(%d): match!\n", pid); ) + addr.sa.sa_family = sa->sa_family; + switch (i->how) { + case EXPLICIT: ipaddr_to_sockaddr(&addr.sa, &i->bindaddr); break; + case SAME: copy_sockaddr(&addr.sa, sa); break; + } + port_to_sockaddr(&addr.sa, 0); + goto found; + } + } + D( fprintf(stderr, "noip(%d): no match; using wildcard\n", pid); ) + wildcard_address(sa->sa_family, &addr.sa); +found: + if (addr.sa.sa_family != AF_INET || !(f&IBF_V6MAPPED)) sa = &addr.sa; + else { map_ipv4_sockaddr(&sin6, &addr.sin); sa = SA(&sin6); } + encode_inet_addr(&sun, sa, ENCF_FRESH); + D( fprintf(stderr, "noip(%d): implicitly binding to %s\n", + pid, sun.sun_path); ) + if (real_bind(sk, SA(&sun), SUN_LEN(&sun))) return (-1); + return (0); +} + +/* The socket SK is about to communicate with the remote address *SA. Ensure + * that the socket has a local address, and adjust *SA to refer to the real + * remote endpoint. + * + * If we need to translate the remote address, then the Unix-domain endpoint + * address will end in *SUN, and *SA will be adjusted to point to it. + */ +static int fixup_client_socket(int sk, const struct sockaddr **sa_r, + socklen_t *len_r, struct sockaddr_un *sun) +{ + struct sockaddr_in sin; + socklen_t mylen = sizeof(*sun); + const struct sockaddr *sa = *sa_r; + unsigned ibf = 0; + + /* If this isn't a Unix-domain socket then there's nothing to do. */ + if (real_getsockname(sk, SA(sun), &mylen) < 0) return (-1); + if (sun->sun_family != AF_UNIX) return (0); + if (mylen < sizeof(*sun)) ((char *)sun)[mylen] = 0; + + /* If the remote address is v6-mapped IPv4, then unmap it so as to search + * for IPv4 servers. Also remember to v6-map the local address when we + * autobind. + */ + if (sa->sa_family == AF_INET6 && !(unmap_ipv4_sockaddr(&sin, SIN6(sa)))) { + sa = SA(&sin); + ibf |= IBF_V6MAPPED; + } + + /* If we're allowed to talk to a real remote endpoint, then fix things up + * as necessary and proceed. + */ + if (acl_allows_p(connect_real, sa)) { + if (fixup_real_ip_socket(sk, (*sa_r)->sa_family, 0)) return (-1); + return (0); + } + + /* Speaking of which, if we don't have a local address, then we should + * arrange one now. + */ + if (!sun->sun_path[0] && do_implicit_bind(sk, sa, ibf)) return (-1); + + /* And then come up with a remote address. */ + encode_inet_addr(sun, sa, 0); + *sa_r = SA(sun); + *len_r = SUN_LEN(sun); + return (0); +} + /*----- Configuration -----------------------------------------------------*/ /* Return the process owner's home directory. */ @@ -950,102 +1319,242 @@ static void parse_ports(char **pp, unsigned short *min, unsigned short *max) *pp = p; } -/* Make a new ACL node. ACT is the verdict; AF is the address family; - * MINADDR and MAXADDR are the ranges on IP addresses; MINPORT and MAXPORT - * are the ranges on port numbers; TAIL is the list tail to attach the new - * node to. - */ -#define ACLNODE(tail_, act_, \ - af_, minaddr_, maxaddr_, minport_, maxport_) do { \ - aclnode *a_; \ - NEW(a_); \ - a_->act = (act_); \ - a_->af = (af_); \ - a_->minaddr = (minaddr_); a_->maxaddr = (maxaddr_); \ - a_->minport = (minport_); a_->maxport = (maxport_); \ - *tail_ = a_; tail_ = &a_->next; \ -} while (0) - -/* Parse an ACL line. *PP points to the end of the line; *TAIL points to - * the list tail (i.e., the final link in the list). An ACL entry has the - * form +|- [any | local | ADDR | ADDR - ADDR | ADDR/ADDR | ADDR/INT] PORTS - * where PORTS is parsed by parse_ports above; an ACL line consists of a - * comma-separated sequence of entries.. +/* Parse an address range designator starting at PP and store a + * representation of it in R. An address range designator has the form: + * + * any | local | ADDR | ADDR - ADDR | ADDR/ADDR | ADDR/INT */ -static void parse_acl_line(char **pp, aclnode ***tail) +static int parse_addrrange(char **pp, addrrange *r) { - ipaddr minaddr, maxaddr; - unsigned short minport, maxport; - int i, af, n; - int act; + char *p = *pp, *q; + int n; int del; - char *p = *pp; - char *q; + int af; - for (;;) { + SKIPSPC; + if (KWMATCHP("any")) r->type = ANY; + else if (KWMATCHP("local")) r->type = LOCAL; + else { + parse_nextaddr(&p, &q, &del); + af = guess_address_family(q); + if (inet_pton(af, q, &r->u.range.min) <= 0) goto bad; + RESCAN(del); SKIPSPC; - if (*p == '+') act = ALLOW; - else if (*p == '-') act = DENY; - else goto bad; + if (*p == '-') { + p++; + parse_nextaddr(&p, &q, &del); + if (inet_pton(af, q, &r->u.range.max) <= 0) goto bad; + RESCAN(del); + } else if (*p == '/') { + p++; + NEXTNUMBER(q, del); + n = strtoul(q, 0, 0); + r->u.range.max = r->u.range.min; + mask_address(af, &r->u.range.min, n, 0); + mask_address(af, &r->u.range.max, n, 1); + RESCAN(del); + } else + r->u.range.max = r->u.range.min; + r->type = RANGE; + r->u.range.af = af; + } + *pp = p; + return (0); - p++; - SKIPSPC; - if (KWMATCHP("any")) { - parse_ports(&p, &minport, &maxport); +bad: + return (-1); +} + +/* Call FUNC on each individual address range in R. */ +static void foreach_addrrange(const addrrange *r, + void (*func)(int af, + const ipaddr *min, + const ipaddr *max, + void *p), + void *p) +{ + ipaddr minaddr, maxaddr; + int i, af; + + switch (r->type) { + case EMPTY: + break; + case ANY: for (i = 0; address_families[i] >= 0; i++) { af = address_families[i]; memset(&minaddr, 0, sizeof(minaddr)); maxaddr = minaddr; mask_address(af, &maxaddr, 0, 1); - ACLNODE(*tail, act, af, minaddr, maxaddr, minport, maxport); + func(af, &minaddr, &maxaddr, p); } - } else if (KWMATCHP("local")) { - parse_ports(&p, &minport, &maxport); + break; + case LOCAL: for (i = 0; address_families[i] >= 0; i++) { af = address_families[i]; memset(&minaddr, 0, sizeof(minaddr)); maxaddr = minaddr; mask_address(af, &maxaddr, 0, 1); - ACLNODE(*tail, act, af, minaddr, minaddr, minport, maxport); - ACLNODE(*tail, act, af, maxaddr, maxaddr, minport, maxport); + func(af, &minaddr, &minaddr, p); + func(af, &maxaddr, &maxaddr, p); } for (i = 0; i < n_local_ipaddrs; i++) { - ACLNODE(*tail, act, local_ipaddrs[i].af, - local_ipaddrs[i].addr, local_ipaddrs[i].addr, - minport, maxport); + func(local_ipaddrs[i].af, + &local_ipaddrs[i].addr, &local_ipaddrs[i].addr, + p); } + break; + case RANGE: + func(r->u.range.af, &r->u.range.min, &r->u.range.max, p); + break; + default: + abort(); + } +} + +struct add_aclnode_ctx { + int act; + unsigned short minport, maxport; + aclnode ***tail; +}; + +static void add_aclnode(int af, const ipaddr *min, const ipaddr *max, + void *p) +{ + struct add_aclnode_ctx *ctx = p; + aclnode *a; + + NEW(a); + a->act = ctx->act; + a->af = af; + a->minaddr = *min; a->maxaddr = *max; + a->minport = ctx->minport; a->maxport = ctx->maxport; + **ctx->tail = a; *ctx->tail = &a->next; +} + +/* Parse an ACL line. *PP points to the end of the line; *TAIL points to + * the list tail (i.e., the final link in the list). An ACL entry has the + * form +|- ADDR-RANGE PORTS + * where PORTS is parsed by parse_ports above; an ACL line consists of a + * comma-separated sequence of entries.. + */ +static void parse_acl_line(char **pp, aclnode ***tail) +{ + struct add_aclnode_ctx ctx; + addrrange r; + char *p = *pp; + + ctx.tail = tail; + for (;;) { + SKIPSPC; + if (*p == '+') ctx.act = ALLOW; + else if (*p == '-') ctx.act = DENY; + else goto bad; + + p++; + if (parse_addrrange(&p, &r)) goto bad; + parse_ports(&p, &ctx.minport, &ctx.maxport); + foreach_addrrange(&r, add_aclnode, &ctx); + SKIPSPC; + if (*p != ',') break; + if (*p) p++; + } + if (*p) goto bad; + *pp = p; + return; + +bad: + D( fprintf(stderr, "noip(%d): bad acl spec (ignored)\n", getpid()); ) + return; +} + +/* Parse an ACL from an environment variable VAR, attaching it to the list + * TAIL. + */ +static void parse_acl_env(const char *var, aclnode ***tail) +{ + char *p, *q; + + if ((p = getenv(var)) != 0) { + p = q = xstrdup(p); + parse_acl_line(&q, tail); + free(p); + } +} + +struct add_impbind_ctx { + int af, how; + ipaddr addr; +}; + +static void add_impbind(int af, const ipaddr *min, const ipaddr *max, + void *p) +{ + struct add_impbind_ctx *ctx = p; + impbind *i; + + if (ctx->af && af != ctx->af) return; + NEW(i); + i->af = af; + i->how = ctx->how; + i->minaddr = *min; i->maxaddr = *max; + switch (ctx->how) { + case EXPLICIT: i->bindaddr = ctx->addr; + case SAME: break; + default: abort(); + } + *impbind_tail = i; impbind_tail = &i->next; +} + +/* Parse an implicit-bind line. An implicit-bind entry has the form + * ADDR-RANGE {ADDR | same} + */ +static void parse_impbind_line(char **pp) +{ + struct add_impbind_ctx ctx; + char *p = *pp, *q; + addrrange r; + int del; + + for (;;) { + if (parse_addrrange(&p, &r)) goto bad; + SKIPSPC; + if (KWMATCHP("same")) { + ctx.how = SAME; + ctx.af = 0; } else { + ctx.how = EXPLICIT; parse_nextaddr(&p, &q, &del); - af = guess_address_family(q); - if (inet_pton(af, q, &minaddr) <= 0) goto bad; + ctx.af = guess_address_family(q); + if (inet_pton(ctx.af, q, &ctx.addr) < 0) goto bad; RESCAN(del); - SKIPSPC; - if (*p == '-') { - p++; - parse_nextaddr(&p, &q, &del); - if (inet_pton(af, q, &maxaddr) <= 0) goto bad; - RESCAN(del); - } else if (*p == '/') { - p++; - NEXTNUMBER(q, del); - n = strtoul(q, 0, 0); - maxaddr = minaddr; - mask_address(af, &minaddr, n, 0); - mask_address(af, &maxaddr, n, 1); - } else - maxaddr = minaddr; - parse_ports(&p, &minport, &maxport); - ACLNODE(*tail, act, af, minaddr, maxaddr, minport, maxport); } + foreach_addrrange(&r, add_impbind, &ctx); SKIPSPC; if (*p != ',') break; - p++; + if (*p) p++; } + if (*p) goto bad; + *pp = p; return; bad: - D( fprintf(stderr, "noip: bad acl spec (ignored)\n"); ) + D( fprintf(stderr, "noip(%d): bad implicit-bind spec (ignored)\n", + getpid()); ) return; } +/* Parse implicit-bind instructions from an environment variable VAR, + * attaching it to the list. + */ +static void parse_impbind_env(const char *var) +{ + char *p, *q; + + if ((p = getenv(var)) != 0) { + p = q = xstrdup(p); + parse_impbind_line(&q); + free(p); + } +} + /* Parse the autoports configuration directive. Syntax is MIN - MAX. */ static void parse_autoports(char **pp) { @@ -1056,29 +1565,19 @@ static void parse_autoports(char **pp) SKIPSPC; NEXTNUMBER(q, del); x = strtoul(q, 0, 0); RESCAN(del); SKIPSPC; - if (*p != '-') goto bad; p++; + if (*p != '-') goto bad; + p++; NEXTNUMBER(q, del); y = strtoul(q, 0, 0); RESCAN(del); minautoport = x; maxautoport = y; + SKIPSPC; if (*p) goto bad; + *pp = p; return; bad: - D( fprintf(stderr, "bad port range (ignored)\n"); ) + D( fprintf(stderr, "noip(%d): bad port range (ignored)\n", getpid()); ) return; } -/* Parse an ACL from an environment variable VAR, attaching it to the list - * TAIL. */ -static void parse_acl_env(const char *var, aclnode ***tail) -{ - char *p, *q; - - if ((p = getenv(var)) != 0) { - p = q = xstrdup(p); - parse_acl_line(&q, tail); - free(p); - } -} - /* Read the configuration from the config file and environment. */ static void readconfig(void) { @@ -1086,9 +1585,11 @@ static void readconfig(void) char buf[1024]; size_t n; char *p, *q, *cmd; + Dpid; parse_acl_env("NOIP_REALBIND_BEFORE", &bind_tail); parse_acl_env("NOIP_REALCONNECT_BEFORE", &connect_tail); + parse_impbind_env("NOIP_IMPBIND_BEFORE"); if ((p = getenv("NOIP_AUTOPORTS")) != 0) { p = q = xstrdup(p); parse_autoports(&q); @@ -1096,11 +1597,11 @@ static void readconfig(void) } if ((p = getenv("NOIP_CONFIG")) == 0) snprintf(p = buf, sizeof(buf), "%s/.noip", home()); - D( fprintf(stderr, "noip: config file: %s\n", p); ) + D( fprintf(stderr, "noip(%d): config file: %s\n", pid, p); ) if ((fp = fopen(p, "r")) == 0) { - D( fprintf(stderr, "noip: couldn't read config: %s\n", - strerror(errno)); ) + D( fprintf(stderr, "noip(%d): couldn't read config: %s\n", + pid, strerror(errno)); ) goto done; } while (fgets(buf, sizeof(buf), fp)) { @@ -1120,95 +1621,172 @@ static void readconfig(void) parse_acl_line(&p, &bind_tail); else if (strcmp(cmd, "realconnect") == 0) parse_acl_line(&p, &connect_tail); + else if (strcmp(cmd, "impbind") == 0) + parse_impbind_line(&p); else if (strcmp(cmd, "autoports") == 0) parse_autoports(&p); else if (strcmp(cmd, "debug") == 0) debug = *p ? atoi(p) : 1; else - D( fprintf(stderr, "noip: bad config command %s\n", cmd); ) + D( fprintf(stderr, "noip(%d): bad config command %s\n", pid, cmd); ) } fclose(fp); done: parse_acl_env("NOIP_REALBIND", &bind_tail); parse_acl_env("NOIP_REALCONNECT", &connect_tail); + parse_impbind_env("NOIP_IMPBIND"); parse_acl_env("NOIP_REALBIND_AFTER", &bind_tail); parse_acl_env("NOIP_REALCONNECT_AFTER", &connect_tail); + parse_impbind_env("NOIP_IMPBIND_AFTER"); *bind_tail = 0; *connect_tail = 0; + *impbind_tail = 0; if (!sockdir) sockdir = getenv("NOIP_SOCKETDIR"); if (!sockdir) { snprintf(buf, sizeof(buf), "%s/noip-%s", tmpdir(), user()); sockdir = xstrdup(buf); } - D( fprintf(stderr, "noip: socketdir: %s\n", sockdir); - fprintf(stderr, "noip: autoports: %u-%u\n", - minautoport, maxautoport); - fprintf(stderr, "noip: realbind acl:\n"); + D( fprintf(stderr, "noip(%d): socketdir: %s\n", pid, sockdir); + fprintf(stderr, "noip(%d): autoports: %u-%u\n", + pid, minautoport, maxautoport); + fprintf(stderr, "noip(%d): realbind acl:\n", pid); dump_acl(bind_real); - fprintf(stderr, "noip: realconnect acl:\n"); - dump_acl(connect_real); ) + fprintf(stderr, "noip(%d): realconnect acl:\n", pid); + dump_acl(connect_real); + fprintf(stderr, "noip(%d): impbind list:\n", pid); + dump_impbind_list(); ) } /*----- Overridden system calls -------------------------------------------*/ +static void dump_syserr(long rc) + { fprintf(stderr, " => %ld (E%d)\n", rc, errno); } + +static void dump_sysresult(long rc) +{ + if (rc < 0) dump_syserr(rc); + else fprintf(stderr, " => %ld\n", rc); +} + +static void dump_addrresult(long rc, const struct sockaddr *sa, + socklen_t len) +{ + char addrbuf[ADDRBUFSZ]; + + if (rc < 0) dump_syserr(rc); + else { + fprintf(stderr, " => %ld [%s]\n", rc, + present_sockaddr(sa, len, addrbuf, sizeof(addrbuf))); + } +} + int socket(int pf, int ty, int proto) { + int sk; + + D( fprintf(stderr, "noip(%d): SOCKET pf=%d, type=%d, proto=%d", + getpid(), pf, ty, proto); ) + switch (pf) { default: if (!family_known_p(pf)) { + D( fprintf(stderr, " -> unknown; refuse\n"); ) errno = EAFNOSUPPORT; - return (-1); + sk = -1; } + D( fprintf(stderr, " -> inet; substitute"); ) pf = PF_UNIX; proto = 0; + break; case PF_UNIX: #ifdef PF_NETLINK case PF_NETLINK: #endif - return (real_socket(pf, ty, proto)); + D( fprintf(stderr, " -> safe; permit"); ) + break; } + sk = real_socket(pf, ty, proto); + D( dump_sysresult(sk); ) + return (sk); } int socketpair(int pf, int ty, int proto, int *sk) { - if (pf == PF_INET) { + int rc; + + D( fprintf(stderr, "noip(%d): SOCKETPAIR pf=%d, type=%d, proto=%d", + getpid(), pf, ty, proto); ) + if (!family_known_p(pf)) + D( fprintf(stderr, " -> unknown; permit"); ) + else { + D( fprintf(stderr, " -> inet; substitute"); ) pf = PF_UNIX; proto = 0; } - return (real_socketpair(pf, ty, proto, sk)); + rc = real_socketpair(pf, ty, proto, sk); + D( if (rc < 0) dump_syserr(rc); + else fprintf(stderr, " => %d (%d, %d)\n", rc, sk[0], sk[1]); ) + return (rc); } int bind(int sk, const struct sockaddr *sa, socklen_t len) { struct sockaddr_un sun; + int rc; + unsigned f; + int reusep; + socklen_t n; + Dpid; + + D({ char buf[ADDRBUFSZ]; + fprintf(stderr, "noip(%d): BIND sk=%d, sa[%d]=%s", pid, + sk, len, present_sockaddr(sa, len, buf, sizeof(buf))); }) - if (family_known_p(sa->sa_family)) { + if (!family_known_p(sa->sa_family)) + D( fprintf(stderr, " -> unknown af; pass through"); ) + else { + D( fprintf(stderr, " -> checking...\n"); ) PRESERVING_ERRNO({ if (acl_allows_p(bind_real, sa)) { - if (fixup_real_ip_socket(sk, sa->sa_family)) + if (fixup_real_ip_socket(sk, sa->sa_family, 0)) return (-1); } else { - encode_inet_addr(&sun, sa, WANT_FRESH); + f = ENCF_FRESH; + n = sizeof(reusep); + if (!getsockopt(sk, SOL_SOCKET, SO_REUSEADDR, &reusep, &n) && reusep) + f |= ENCF_REUSEADDR; + encode_inet_addr(&sun, sa, f); sa = SA(&sun); len = SUN_LEN(&sun); } }); + D( fprintf(stderr, "noip(%d): BIND ...", pid); ) } - return (real_bind(sk, sa, len)); + rc = real_bind(sk, sa, len); + D( dump_sysresult(rc); ) + return (rc); } int connect(int sk, const struct sockaddr *sa, socklen_t len) { struct sockaddr_un sun; int rc; + Dpid; - if (!family_known_p(sa->sa_family)) + D({ char buf[ADDRBUFSZ]; + fprintf(stderr, "noip(%d): CONNECT sk=%d, sa[%d]=%s", pid, + sk, len, present_sockaddr(sa, len, buf, sizeof(buf))); }) + + if (!family_known_p(sa->sa_family)) { + D( fprintf(stderr, " -> unknown af; pass through"); ) rc = real_connect(sk, sa, len); - else { + } else { + D( fprintf(stderr, " -> checking...\n"); ) PRESERVING_ERRNO({ - do_implicit_bind(sk, &sa, &len, &sun); + fixup_client_socket(sk, &sa, &len, &sun); }); + D( fprintf(stderr, "noip(%d): CONNECT ...", pid); ) rc = real_connect(sk, sa, len); if (rc < 0) { switch (errno) { @@ -1216,6 +1794,7 @@ int connect(int sk, const struct sockaddr *sa, socklen_t len) } } } + D( dump_sysresult(rc); ) return (rc); } @@ -1223,13 +1802,28 @@ ssize_t sendto(int sk, const void *buf, size_t len, int flags, const struct sockaddr *to, socklen_t tolen) { struct sockaddr_un sun; + ssize_t n; + Dpid; + + D({ char addrbuf[ADDRBUFSZ]; + fprintf(stderr, "noip(%d): SENDTO sk=%d, len=%lu, flags=%d, to[%d]=%s", + pid, sk, (unsigned long)len, flags, tolen, + present_sockaddr(to, tolen, addrbuf, sizeof(addrbuf))); }) - if (to && to->sa_family == AF_INET) { + if (!to) + D( fprintf(stderr, " -> null address; leaving"); ) + else if (!family_known_p(to->sa_family)) + D( fprintf(stderr, " -> unknown af; pass through"); ) + else { + D( fprintf(stderr, " -> checking...\n"); ) PRESERVING_ERRNO({ - do_implicit_bind(sk, &to, &tolen, &sun); + fixup_client_socket(sk, &to, &tolen, &sun); }); + D( fprintf(stderr, "noip(%d): SENDTO ...", pid); ) } - return (real_sendto(sk, buf, len, flags, to, tolen)); + n = real_sendto(sk, buf, len, flags, to, tolen); + D( dump_sysresult(n); ) + return (n); } ssize_t recvfrom(int sk, void *buf, size_t len, int flags, @@ -1238,57 +1832,91 @@ ssize_t recvfrom(int sk, void *buf, size_t len, int flags, char sabuf[1024]; socklen_t mylen = sizeof(sabuf); ssize_t n; + Dpid; - if (!from) - return real_recvfrom(sk, buf, len, flags, 0, 0); - PRESERVING_ERRNO({ + D( fprintf(stderr, "noip(%d): RECVFROM sk=%d, len=%lu, flags=%d", + pid, sk, (unsigned long)len, flags); ) + + if (!from) { + D( fprintf(stderr, " -> null addr; pass through"); ) + n = real_recvfrom(sk, buf, len, flags, 0, 0); + } else { n = real_recvfrom(sk, buf, len, flags, SA(sabuf), &mylen); - if (n < 0) - return (-1); - return_fake_name(SA(sabuf), mylen, from, fromlen); - }); + if (n >= 0) { + D( fprintf(stderr, " -> converting...\n"); ) + PRESERVING_ERRNO({ + return_fake_peer(sk, SA(sabuf), mylen, from, fromlen); + }); + D( fprintf(stderr, "noip(%d): ... RECVFROM", pid); ) + } + } + D( dump_addrresult(n, from, fromlen ? *fromlen : 0); ) return (n); } ssize_t sendmsg(int sk, const struct msghdr *msg, int flags) { struct sockaddr_un sun; - const struct sockaddr *sa; + const struct sockaddr *sa = SA(msg->msg_name); struct msghdr mymsg; - - if (msg->msg_name && SA(msg->msg_name)->sa_family == AF_INET) { + ssize_t n; + Dpid; + + D({ char addrbuf[ADDRBUFSZ]; + fprintf(stderr, "noip(%d): SENDMSG sk=%d, " + "msg_flags=%d, msg_name[%d]=%s, ...", + pid, sk, msg->msg_flags, msg->msg_namelen, + present_sockaddr(sa, msg->msg_namelen, + addrbuf, sizeof(addrbuf))); }) + + if (!sa) + D( fprintf(stderr, " -> null address; leaving"); ) + else if (!family_known_p(sa->sa_family)) + D( fprintf(stderr, " -> unknown af; pass through"); ) + else { + D( fprintf(stderr, " -> checking...\n"); ) PRESERVING_ERRNO({ - sa = SA(msg->msg_name); mymsg = *msg; - do_implicit_bind(sk, &sa, &mymsg.msg_namelen, &sun); + fixup_client_socket(sk, &sa, &mymsg.msg_namelen, &sun); mymsg.msg_name = SA(sa); msg = &mymsg; }); + D( fprintf(stderr, "noip(%d): SENDMSG ...", pid); ) } - return (real_sendmsg(sk, msg, flags)); + n = real_sendmsg(sk, msg, flags); + D( dump_sysresult(n); ) + return (n); } ssize_t recvmsg(int sk, struct msghdr *msg, int flags) { char sabuf[1024]; - struct sockaddr *sa; - socklen_t len; + struct sockaddr *sa = SA(msg->msg_name); + socklen_t len = msg->msg_namelen; ssize_t n; + Dpid; + + D( fprintf(stderr, "noip(%d): RECVMSG sk=%d msg_flags=%d, ...", + pid, sk, msg->msg_flags); ) - if (!msg->msg_name) + if (!msg->msg_name) { + D( fprintf(stderr, " -> null addr; pass through"); ) return (real_recvmsg(sk, msg, flags)); - PRESERVING_ERRNO({ - sa = SA(msg->msg_name); - len = msg->msg_namelen; + } else { msg->msg_name = sabuf; msg->msg_namelen = sizeof(sabuf); n = real_recvmsg(sk, msg, flags); - if (n < 0) - return (-1); - return_fake_name(SA(sabuf), msg->msg_namelen, sa, &len); + if (n >= 0) { + D( fprintf(stderr, " -> converting...\n"); ) + PRESERVING_ERRNO({ + return_fake_peer(sk, SA(sabuf), msg->msg_namelen, sa, &len); + }); + } + D( fprintf(stderr, "noip(%d): ... RECVMSG", pid); ) msg->msg_name = sa; msg->msg_namelen = len; - }); + } + D( dump_addrresult(n, sa, len); ) return (n); } @@ -1296,44 +1924,66 @@ int accept(int sk, struct sockaddr *sa, socklen_t *len) { char sabuf[1024]; socklen_t mylen = sizeof(sabuf); - int nsk = real_accept(sk, SA(sabuf), &mylen); + int nsk; + Dpid; - if (nsk < 0) - return (-1); - return_fake_name(SA(sabuf), mylen, sa, len); + D( fprintf(stderr, "noip(%d): ACCEPT sk=%d", pid, sk); ) + + nsk = real_accept(sk, SA(sabuf), &mylen); + if (nsk < 0) /* failed */; + else if (!sa) D( fprintf(stderr, " -> address not wanted"); ) + else { + D( fprintf(stderr, " -> converting...\n"); ) + return_fake_peer(sk, SA(sabuf), mylen, sa, len); + D( fprintf(stderr, "noip(%d): ... ACCEPT", pid); ) + } + D( dump_addrresult(nsk, sa, len ? *len : 0); ) return (nsk); } int getsockname(int sk, struct sockaddr *sa, socklen_t *len) { - PRESERVING_ERRNO({ - char sabuf[1024]; - socklen_t mylen = sizeof(sabuf); - if (real_getsockname(sk, SA(sabuf), &mylen)) - return (-1); - return_fake_name(SA(sabuf), mylen, sa, len); - }); - return (0); + char sabuf[1024]; + socklen_t mylen = sizeof(sabuf); + int rc; + Dpid; + + D( fprintf(stderr, "noip(%d): GETSOCKNAME sk=%d", pid, sk); ) + rc = real_getsockname(sk, SA(sabuf), &mylen); + if (rc >= 0) { + D( fprintf(stderr, " -> converting...\n"); ) + return_fake_name(SA(sabuf), mylen, sa, len, 0); + D( fprintf(stderr, "noip(%d): ... GETSOCKNAME", pid); ) + } + D( dump_addrresult(rc, sa, *len); ) + return (rc); } int getpeername(int sk, struct sockaddr *sa, socklen_t *len) { - PRESERVING_ERRNO({ - char sabuf[1024]; - socklen_t mylen = sizeof(sabuf); - if (real_getpeername(sk, SA(sabuf), &mylen)) - return (-1); - return_fake_name(SA(sabuf), mylen, sa, len); - }); - return (0); + char sabuf[1024]; + socklen_t mylen = sizeof(sabuf); + int rc; + Dpid; + + D( fprintf(stderr, "noip(%d): GETPEERNAME sk=%d", pid, sk); ) + rc = real_getpeername(sk, SA(sabuf), &mylen); + if (rc >= 0) { + D( fprintf(stderr, " -> converting...\n"); ) + return_fake_peer(sk, SA(sabuf), mylen, sa, len); + D( fprintf(stderr, "noip(%d): ... GETPEERNAME", pid); ) + } + D( dump_addrresult(rc, sa, *len); ) + return (rc); } int getsockopt(int sk, int lev, int opt, void *p, socklen_t *len) { switch (lev) { - case SOL_IP: - case SOL_TCP: - case SOL_UDP: + case IPPROTO_IP: + case IPPROTO_IPV6: + case IPPROTO_TCP: + case IPPROTO_UDP: if (*len > 0) memset(p, 0, *len); return (0); @@ -1344,9 +1994,10 @@ int getsockopt(int sk, int lev, int opt, void *p, socklen_t *len) int setsockopt(int sk, int lev, int opt, const void *p, socklen_t len) { switch (lev) { - case SOL_IP: - case SOL_TCP: - case SOL_UDP: + case IPPROTO_IP: + case IPPROTO_IPV6: + case IPPROTO_TCP: + case IPPROTO_UDP: return (0); } switch (opt) { @@ -1358,6 +2009,36 @@ int setsockopt(int sk, int lev, int opt, const void *p, socklen_t len) return (real_setsockopt(sk, lev, opt, p, len)); } +int ioctl(int fd, unsigned long op, ...) +{ + va_list ap; + void *arg; + int sk; + int rc; + + va_start(ap, op); + arg = va_arg(ap, void *); + + switch (op) { + case SIOCGIFADDR: + case SIOCGIFBRDADDR: + case SIOCGIFDSTADDR: + case SIOCGIFNETMASK: + PRESERVING_ERRNO({ + if (fixup_real_ip_socket(fd, AF_INET, &sk)) goto real; + }); + rc = real_ioctl(sk, op, arg); + PRESERVING_ERRNO({ close(sk); }); + break; + default: + real: + rc = real_ioctl(fd, op, arg); + break; + } + va_end(ap); + return (rc); +} + /*----- Initialization ----------------------------------------------------*/ /* Clean up the socket directory, deleting stale sockets. */ @@ -1368,6 +2049,7 @@ static void cleanup_sockdir(void) address addr; struct sockaddr_un sun; struct stat st; + Dpid; if ((dir = opendir(sockdir)) == 0) return; sun.sun_family = AF_UNIX; @@ -1378,13 +2060,13 @@ static void cleanup_sockdir(void) if (decode_inet_addr(&addr.sa, 0, &sun, SUN_LEN(&sun)) || stat(sun.sun_path, &st) || !S_ISSOCK(st.st_mode)) { - D( fprintf(stderr, "noip: ignoring unknown socketdir entry `%s'\n", - sun.sun_path); ) + D( fprintf(stderr, "noip(%d): ignoring unknown socketdir entry `%s'\n", + pid, sun.sun_path); ) continue; } if (unix_socket_status(&sun, 0) == STALE) { - D( fprintf(stderr, "noip: clearing away stale socket %s\n", - d->d_name); ) + D( fprintf(stderr, "noip(%d): clearing away stale socket %s\n", + pid, d->d_name); ) unlink(sun.sun_path); } } @@ -1399,7 +2081,9 @@ static void get_local_ipaddrs(void) struct ifaddrs *ifa_head, *ifa; ipaddr a; int i; + Dpid; + D( fprintf(stderr, "noip(%d): fetching local addresses...\n", pid); ) if (getifaddrs(&ifa_head)) { perror("getifaddrs"); return; } for (n_local_ipaddrs = 0, ifa = ifa_head; n_local_ipaddrs < MAX_LOCAL_IPADDRS && ifa; @@ -1408,7 +2092,8 @@ static void get_local_ipaddrs(void) continue; ipaddr_from_sockaddr(&a, ifa->ifa_addr); D({ char buf[ADDRBUFSZ]; - fprintf(stderr, "noip: local addr %s = %s", ifa->ifa_name, + fprintf(stderr, "noip(%d): local addr %s = %s", pid, + ifa->ifa_name, inet_ntop(ifa->ifa_addr->sa_family, &a, buf, sizeof(buf))); }) for (i = 0; i < n_local_ipaddrs; i++) { @@ -1436,13 +2121,13 @@ static void create_sockdir(void) { struct stat st; - if (stat(sockdir, &st)) { + if (lstat(sockdir, &st)) { if (errno == ENOENT) { if (mkdir(sockdir, 0700)) { perror("noip: creating socketdir"); exit(127); } - if (!stat(sockdir, &st)) + if (!lstat(sockdir, &st)) goto check; } perror("noip: checking socketdir");