X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~mdw/git/preload-hacks/blobdiff_plain/e4976bb0731d14a7d8bfa53067ec1d99e94617cb..dc3956b3f2f9b13bbf93df2ed7295407cc90ab86:/noip.c diff --git a/noip.c b/noip.c index 735a58a..ee86680 100644 --- a/noip.c +++ b/noip.c @@ -1,10 +1,41 @@ +/* -*-c-*- + * + * Make programs use Unix-domain sockets instead of IP + * + * (c) 2008 Straylight/Edgeware + */ + +/*----- Licensing notice --------------------------------------------------* + * + * This file is part of the preload-hacks package. + * + * Preload-hacks are free software; you can redistribute it and/or modify + * them under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or (at + * your option) any later version. + * + * Preload-hacks are distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY + * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * for more details. + * + * You should have received a copy of the GNU General Public License along + * with preload-hacks; if not, write to the Free Software Foundation, Inc., + * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + */ + #define _GNU_SOURCE #undef sun #undef SUN #define DEBUG +/*----- Header files ------------------------------------------------------*/ + +#include #include #include +#include +#include #include #include @@ -23,31 +54,63 @@ #include #include #include -#include +#include +#include + +/*----- Data structures ---------------------------------------------------*/ + +enum { UNUSED, STALE, USED }; /* Unix socket status values */ +enum { WANT_FRESH, WANT_EXISTING }; /* Socket address dispositions */ +enum { DENY, ALLOW }; /* ACL verdicts */ + +static int address_families[] = { AF_INET, AF_INET6, -1 }; + +#define ADDRBUFSZ 64 -enum { UNUSED, STALE, USED }; -enum { WANT_FRESH, WANT_EXISTING }; -enum { DENY, ALLOW }; +/* Address representations. */ +typedef union ipaddr { + struct in_addr v4; + struct in6_addr v6; +} ipaddr; + +/* Convenient socket address hacking. */ +typedef union address { + struct sockaddr sa; + struct sockaddr_in sin; + struct sockaddr_in6 sin6; +} address; + +/* Access control list nodes */ typedef struct aclnode { struct aclnode *next; int act; - unsigned long minaddr, maxaddr; + int af; + ipaddr minaddr, maxaddr; unsigned short minport, maxport; } aclnode; -#define MAX_LOCAL_IPADDRS 16 -static struct in_addr local_ipaddrs[MAX_LOCAL_IPADDRS]; +/* Local address records */ +typedef struct full_ipaddr { + int af; + ipaddr addr; +} full_ipaddr; +#define MAX_LOCAL_IPADDRS 64 +static full_ipaddr local_ipaddrs[MAX_LOCAL_IPADDRS]; static int n_local_ipaddrs; +/* General configuration */ static uid_t uid; static char *sockdir = 0; static int debug = 0; +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; -/* --- Import magic --- */ +/*----- Import the real versions of functions -----------------------------*/ +/* The list of functions to immport. */ #define IMPORTS(_) \ _(socket, int, (int, int, int)) \ _(socketpair, int, (int, int, int, int *)) \ @@ -61,16 +124,17 @@ static aclnode *connect_real, **connect_tail = &connect_real; _(sendto, ssize_t, (int, const void *buf, size_t, int, \ const struct sockaddr *to, socklen_t tolen)) \ _(recvfrom, ssize_t, (int, void *buf, size_t, int, \ - struct sockaddr *from, socklen_t *fromlen)) \ + struct sockaddr *from, socklen_t *fromlen)) \ _(sendmsg, ssize_t, (int, const struct msghdr *, int)) \ _(recvmsg, ssize_t, (int, struct msghdr *, int)) \ - _(close, int, (int)) + _(ioctl, int, (int, unsigned long, ...)) +/* Function pointers to set up. */ #define DECL(imp, ret, args) static ret (*real_##imp) args; IMPORTS(DECL) #undef DECL -static void setup(void) __attribute__((constructor)); +/* Import the system calls. */ static void import(void) { #define IMPORT(imp, ret, args) \ @@ -79,35 +143,45 @@ static void import(void) #undef IMPORT } -/* --- Support --- */ +/*----- Utilities ---------------------------------------------------------*/ +/* Socket address casts */ #define SA(sa) ((struct sockaddr *)(sa)) #define SIN(sa) ((struct sockaddr_in *)(sa)) +#define SIN6(sa) ((struct sockaddr_in6 *)(sa)) #define SUN(sa) ((struct sockaddr_un *)(sa)) +/* Raw bytes */ #define UC(ch) ((unsigned char)(ch)) +/* Memory allocation */ #define NEW(x) ((x) = xmalloc(sizeof(*x))) #define NEWV(x, n) ((x) = xmalloc(sizeof(*x) * (n))) +/* 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 */ #define PRESERVING_ERRNO(body) do { \ int _err = errno; { body } errno = _err; \ } while (0) +/* Allocate N bytes of memory; abort on failure. */ static void *xmalloc(size_t n) { void *p; if (!n) return (0); - if ((p = malloc(n)) == 0) { perror("malloc"); exit(1); } + if ((p = malloc(n)) == 0) { perror("malloc"); exit(127); } return (p); } +/* Allocate a copy of the null-terminated string P; abort on failure. */ static char *xstrdup(const char *p) { size_t n = strlen(p) + 1; @@ -116,59 +190,339 @@ static char *xstrdup(const char *p) return (q); } -static int unix_socket_status(struct sockaddr_un *sun, int quick_p) +/*----- Address-type hacking ----------------------------------------------*/ + +/* If M is a simple mask, i.e., consists of a sequence of zero bits followed + * by a sequence of one bits, then return the length of the latter sequence + * (which may be zero); otherwise return -1. + */ +static int simple_mask_length(unsigned long m) { - struct stat st; - FILE *fp = 0; - size_t len, n; - int rc; - char buf[256]; + int n = 0; - rc = UNUSED; - if (stat(sun->sun_path, &st) && errno == ENOENT) - goto done; - rc = USED; - if (quick_p) - goto done; + while (m & 1) { n++; m >>= 1; } + return (m ? -1 : n); +} - if ((fp = fopen("/proc/net/unix", "r")) == 0) - goto done; - fgets(buf, sizeof(buf), fp); /* skip header */ - len = strlen(sun->sun_path); - 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; +/* Answer whether AF is an interesting address family. */ +static int family_known_p(int af) +{ + switch (af) { + case AF_INET: + case AF_INET6: + return (1); + default: + return (0); } - if (ferror(fp)) - goto done; - rc = STALE; -done: - if (fp) fclose(fp); - return (rc); } -#ifdef DEBUG +/* Return the socket address length for address family AF. */ +static socklen_t family_socklen(int af) +{ + switch (af) { + case AF_INET: return (sizeof(struct sockaddr_in)); + case AF_INET6: return (sizeof(struct sockaddr_in6)); + default: abort(); + } +} + +/* Return the width of addresses of kind AF. */ +static int address_width(int af) +{ + switch (af) { + case AF_INET: return 32; + case AF_INET6: return 128; + default: abort(); + } +} -static void dump_aclnode(aclnode *a) +/* If addresses A and B share a common prefix then return its length; + * otherwise return -1. + */ +static int common_prefix_length(int af, const ipaddr *a, const ipaddr *b) { - char minbuf[16], maxbuf[16]; - struct in_addr amin, amax; + switch (af) { + case AF_INET: { + unsigned long aa = ntohl(a->v4.s_addr), bb = ntohl(b->v4.s_addr); + unsigned long m = aa^bb; + if ((aa&m) == 0 && (bb&m) == m) return (32 - simple_mask_length(m)); + else return (-1); + } break; + case AF_INET6: { + const uint8_t *aa = a->v6.s6_addr, *bb = b->v6.s6_addr; + unsigned m; + unsigned n; + int i; + + for (i = 0; i < 16 && aa[i] == bb[i]; i++); + n = 8*i; + if (i < 16) { + m = aa[i]^bb[i]; + if ((aa[i]&m) != 0 || (bb[i]&m) != m) return (-1); + n += 8 - simple_mask_length(m); + for (i++; i < 16; i++) + if (aa[i] || bb[i] != 0xff) return (-1); + } + return (n); + } break; + default: + abort(); + } +} - amin.s_addr = htonl(a->minaddr); - amax.s_addr = htonl(a->maxaddr); - fprintf(stderr, "noip: %c ", a->act ? '+' : '-'); - if (a->minaddr == 0 && a->maxaddr == 0xffffffff) - fprintf(stderr, "any"); - else { - fprintf(stderr, "%s", - inet_ntop(AF_INET, &amin, minbuf, sizeof(minbuf))); - if (a->maxaddr != a->minaddr) { - fprintf(stderr, "-%s", - inet_ntop(AF_INET, &amax, maxbuf, sizeof(maxbuf))); - } +/* Extract the port number (in host byte-order) from SA. */ +static int port_from_sockaddr(const struct sockaddr *sa) +{ + switch (sa->sa_family) { + case AF_INET: return (ntohs(SIN(sa)->sin_port)); + case AF_INET6: return (ntohs(SIN6(sa)->sin6_port)); + default: abort(); + } +} + +/* Store the port number PORT (in host byte-order) in SA. */ +static void port_to_sockaddr(struct sockaddr *sa, int port) +{ + switch (sa->sa_family) { + case AF_INET: SIN(sa)->sin_port = htons(port); break; + case AF_INET6: SIN6(sa)->sin6_port = htons(port); break; + default: abort(); + } +} + +/* Extract the address part from SA and store it in A. */ +static void ipaddr_from_sockaddr(ipaddr *a, const struct sockaddr *sa) +{ + switch (sa->sa_family) { + case AF_INET: a->v4 = SIN(sa)->sin_addr; break; + case AF_INET6: a->v6 = SIN6(sa)->sin6_addr; 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)); } + +/* Answer whether two addresses are equal. */ +static int ipaddr_equal_p(int af, const ipaddr *a, const ipaddr *b) +{ + switch (af) { + case AF_INET: return (a->v4.s_addr == b->v4.s_addr); + case AF_INET6: return (memcmp(a->v6.s6_addr, b->v6.s6_addr, 16) == 0); + default: abort(); + } +} + +/* Answer whether the address part of SA is between A and B (inclusive). We + * assume that SA has the correct address family. + */ +static int sockaddr_in_range_p(const struct sockaddr *sa, + const ipaddr *a, const ipaddr *b) +{ + switch (sa->sa_family) { + case AF_INET: { + unsigned long addr = ntohl(SIN(sa)->sin_addr.s_addr); + return (ntohl(a->v4.s_addr) <= addr && + addr <= ntohl(b->v4.s_addr)); + } break; + case AF_INET6: { + const uint8_t *ss = SIN6(sa)->sin6_addr.s6_addr; + const uint8_t *aa = a->v6.s6_addr, *bb = b->v6.s6_addr; + int h = 1, l = 1; + int i; + + for (i = 0; h && l && i < 16; i++, ss++, aa++, bb++) { + if (*ss < *aa || *bb < *ss) return (0); + if (*aa < *ss) l = 0; + if (*ss < *bb) h = 0; + } + return (1); + } break; + default: + abort(); + } +} + +/* Fill in SA with the appropriate wildcard address. */ +static void wildcard_address(int af, struct sockaddr *sa) +{ + switch (af) { + case AF_INET: { + struct sockaddr_in *sin = SIN(sa); + memset(sin, 0, sizeof(*sin)); + sin->sin_family = AF_INET; + sin->sin_port = 0; + sin->sin_addr.s_addr = INADDR_ANY; + } break; + case AF_INET6: { + struct sockaddr_in6 *sin6 = SIN6(sa); + memset(sin6, 0, sizeof(*sin6)); + sin6->sin6_family = AF_INET6; + sin6->sin6_port = 0; + sin6->sin6_addr = in6addr_any; + sin6->sin6_scope_id = 0; + sin6->sin6_flowinfo = 0; + } break; + default: + abort(); + } +} + +/* Mask the address A, forcing all but the top PLEN bits to zero or one + * according to HIGHP. + */ +static void mask_address(int af, ipaddr *a, int plen, int highp) +{ + switch (af) { + case AF_INET: { + unsigned long addr = ntohl(a->v4.s_addr); + unsigned long mask = plen ? ~0ul << (32 - plen) : 0; + addr &= mask; + if (highp) addr |= ~mask; + a->v4.s_addr = htonl(addr & 0xffffffff); + } break; + case AF_INET6: { + int i = plen/8; + unsigned m = (0xff << (8 - plen%8)) & 0xff; + unsigned s = highp ? 0xff : 0; + if (m) { + a->v6.s6_addr[i] = (a->v6.s6_addr[i] & m) | (s & ~m); + i++; + } + for (; i < 16; i++) a->v6.s6_addr[i] = s; + } break; + default: + abort(); + } +} + +/* Write a presentation form of SA to BUF, a buffer of length SZ. LEN is the + * address length; if it's zero, look it up based on the address family. + * Return a pointer to the string (which might, in an emergency, be a static + * string rather than your buffer). + */ +static char *present_sockaddr(const struct sockaddr *sa, socklen_t len, + char *buf, size_t sz) +{ +#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); + + switch (sa->sa_family) { + case AF_UNIX: { + struct sockaddr_un *sun = SUN(sa); + char *p = sun->sun_path; + size_t n = len - offsetof(struct sockaddr_un, sun_path); + + assert(n); + if (*p == 0) { + WANT(1); PUTC('@'); + p++; n--; + while (n) { + switch (*p) { + case 0: WANT(2); PUTC('\\'); PUTC('0'); break; + case '\a': WANT(2); PUTC('\\'); PUTC('a'); break; + case '\n': WANT(2); PUTC('\\'); PUTC('n'); break; + case '\r': WANT(2); PUTC('\\'); PUTC('r'); break; + case '\t': WANT(2); PUTC('\\'); PUTC('t'); break; + case '\v': WANT(2); PUTC('\\'); PUTC('v'); break; + case '\\': WANT(2); PUTC('\\'); PUTC('\\'); break; + default: + if (*p > ' ' && *p <= '~') + { WANT(1); PUTC(*p); } + else { + WANT(4); PUTC('\\'); PUTC('x'); + PUTC((*p >> 4)&0xf); PUTC((*p >> 0)&0xf); + } + break; + } + p++; n--; + } + } else { + if (*p != '/') { WANT(2); PUTC('.'); PUTC('/'); } + while (n && *p) { WANT(1); PUTC(*p); p++; n--; } + } + WANT(1); PUTC(0); + } break; + case AF_INET: case AF_INET6: { + char addrbuf[NI_MAXHOST], portbuf[NI_MAXSERV]; + int err = getnameinfo(sa, len, + addrbuf, sizeof(addrbuf), + portbuf, sizeof(portbuf), + NI_NUMERICHOST | NI_NUMERICSERV); + assert(!err); + snprintf(buf, sz, strchr(addrbuf, ':') ? "[%s]:%s" : "%s:%s", + addrbuf, portbuf); + } break; + default: + snprintf(buf, sz, "", sa->sa_family); + break; } + return (buf); + +nospace: + buf[sz - 1] = 0; + return (buf); +} + +/* Guess the family of a textual socket address. */ +static int guess_address_family(const char *p) + { return (strchr(p, ':') ? AF_INET6 : AF_INET); } + +/* Parse a socket address P and write the result to SA. */ +static int parse_sockaddr(struct sockaddr *sa, const char *p) +{ + char buf[ADDRBUFSZ]; + char *q; + struct addrinfo *ai, ai_hint = { 0 }; + + if (strlen(p) >= sizeof(buf) - 1) return (-1); + strcpy(buf, p); p = buf; + if (*p != '[') { + if ((q = strchr(p, ':')) == 0) return (-1); + *q++ = 0; + } else { + p++; + if ((q = strchr(p, ']')) == 0) return (-1); + *q++ = 0; + if (*q != ':') return (-1); + q++; + } + + ai_hint.ai_family = AF_UNSPEC; + ai_hint.ai_socktype = SOCK_DGRAM; + ai_hint.ai_flags = AI_NUMERICHOST | AI_NUMERICSERV; + if (getaddrinfo(p, q, &ai_hint, &ai)) return (-1); + memcpy(sa, ai->ai_addr, ai->ai_addrlen); + freeaddrinfo(ai); + return (0); +} + +/*----- Access control lists ----------------------------------------------*/ + +#ifdef DEBUG + +/* Write to standard error a description of the ACL node A. */ +static void dump_aclnode(const aclnode *a) +{ + char buf[ADDRBUFSZ]; + const char *p; + int plen; + + fprintf(stderr, "noip(%d): %c ", getpid(), a->act ? '+' : '-'); + plen = common_prefix_length(a->af, &a->minaddr, &a->maxaddr); + p = inet_ntop(a->af, &a->minaddr, buf, sizeof(buf)); + fprintf(stderr, strchr(p, ':') ? "[%s]" : "%s", p); + if (plen < 0) { + p = inet_ntop(a->af, &a->maxaddr, buf, sizeof(buf)); + fprintf(stderr, strchr(p, ':') ? "-[%s]" : "-%s", p); + } else if (plen < address_width(a->af)) + fprintf(stderr, "/%d", plen); if (a->minport != 0 || a->maxport != 0xffff) { fprintf(stderr, ":%u", (unsigned)a->minport); if (a->minport != a->maxport) @@ -177,79 +531,145 @@ static void dump_aclnode(aclnode *a) fputc('\n', stderr); } +static void dump_acl(const aclnode *a) +{ + int act = ALLOW; + + for (; a; a = a->next) { + dump_aclnode(a); + act = a->act; + } + fprintf(stderr, "noip(%d): [default policy: %s]\n", getpid(), + act == ALLOW ? "DENY" : "ALLOW"); +} + #endif -static int acl_allows_p(aclnode *a, const struct sockaddr_in *sin) +/* Returns nonzero if the ACL A allows the socket address SA. */ +static int acl_allows_p(const aclnode *a, const struct sockaddr *sa) { - unsigned long addr = ntohl(sin->sin_addr.s_addr); - unsigned short port = ntohs(sin->sin_port); + unsigned short port = port_from_sockaddr(sa); int act = ALLOW; + Dpid; - D( char buf[16]; - fprintf(stderr, "noip: check %s:%u\n", - inet_ntop(AF_INET, &sin->sin_addr, buf, sizeof(buf)), - ntohs((unsigned)sin->sin_port)); ) + D({ char buf[ADDRBUFSZ]; + 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 (a->minaddr <= addr && addr <= a->maxaddr && + if (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); } -#ifdef DEBUG +/*----- Socket address conversion -----------------------------------------*/ -static void dump_acl(aclnode *a) +/* Return a uniformly distributed integer between MIN and MAX inclusive. */ +static unsigned randrange(unsigned min, unsigned max) { - int act = ALLOW; - - for (; a; a = a->next) { - dump_aclnode(a); - act = a->act; - } - fprintf(stderr, "noip: [default policy: %s]\n", - act == ALLOW ? "DENY" : "ALLOW"); + unsigned mask, i; + + /* It's so nice not to have to care about the quality of the generator + * much! + */ + max -= min; + for (mask = 1; mask < max; mask = (mask << 1) | 1) + ; + do i = rand() & mask; while (i > max); + return (i + min); } -#endif +/* Return the status of Unix-domain socket address SUN. Returns: UNUSED if + * the socket doesn't exist; USED if the path refers to an active socket, or + * isn't really a socket at all, or we can't tell without a careful search + * and QUICKP is set; or STALE if the file refers to a socket which isn't + * being used any more. + */ +static int unix_socket_status(struct sockaddr_un *sun, int quickp) +{ + struct stat st; + FILE *fp = 0; + size_t len, n; + int rc; + char buf[256]; + if (stat(sun->sun_path, &st)) + return (errno == ENOENT ? UNUSED : USED); + if (!S_ISSOCK(st.st_mode) || quickp) + return (USED); + 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); + 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; + } + if (ferror(fp)) + goto done; + rc = STALE; +done: + if (fp) fclose(fp); + 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. + */ static int encode_inet_addr(struct sockaddr_un *sun, - const struct sockaddr_in *sin, + const struct sockaddr *sa, int want) { int i; - int desperate_p = 0; - char buf[INET_ADDRSTRLEN]; + int desperatep = 0; + address addr; + char buf[ADDRBUFSZ]; int rc; - D( fprintf(stderr, "noip: encode %s:%u (%s)", - inet_ntop(AF_INET, &sin->sin_addr, buf, sizeof(buf)), - (unsigned)ntohs(sin->sin_port), + D( fprintf(stderr, "noip(%d): encode %s (%s)", getpid(), + present_sockaddr(sa, 0, buf, sizeof(buf)), want == WANT_EXISTING ? "EXISTING" : "FRESH"); ) sun->sun_family = AF_UNIX; - if (sin->sin_port || want == WANT_EXISTING) { - snprintf(sun->sun_path, sizeof(sun->sun_path), "%s/%s:%u", sockdir, - inet_ntop(AF_INET, &sin->sin_addr, buf, sizeof(buf)), - (unsigned)ntohs(sin->sin_port)); + 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) { - snprintf(sun->sun_path, sizeof(sun->sun_path), "%s/0.0.0.0:%u", - sockdir, (unsigned)ntohs(sin->sin_port)); + 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); } } else { - for (desperate_p = 0; desperate_p < 2; desperate_p++) { - for (i = 16384; i < 65536; i++) { - snprintf(sun->sun_path, sizeof(sun->sun_path), "%s/%s:%u", sockdir, - inet_ntop(AF_INET, &sin->sin_addr, buf, sizeof(buf)), - (unsigned)i); - rc = unix_socket_status(sun, !desperate_p); + copy_sockaddr(&addr.sa, sa); + 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; + } + 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; @@ -265,27 +685,28 @@ static int encode_inet_addr(struct sockaddr_un *sun, return (0); } -static int decode_inet_addr(struct sockaddr_in *sin, +/* 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) 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, socklen_t len) { - char buf[INET_ADDRSTRLEN + 16]; - char *p; - size_t n = strlen(sockdir), nn = strlen(sun->sun_path); - struct sockaddr_in sin_mine; - unsigned long port; - - if (!sin) - sin = &sin_mine; - if (sun->sun_family != AF_UNIX) - return (-1); - if (len < sizeof(sun)) ((char *)sun)[len] = 0; - D( fprintf(stderr, "noip: decode (%d) `%s'", - *sun->sun_path, sun->sun_path); ) - if (!sun->sun_path[0]) { - sin->sin_family = AF_INET; - sin->sin_addr.s_addr = INADDR_ANY; - sin->sin_port = 0; + char buf[ADDRBUFSZ]; + size_t n = strlen(sockdir), nn; + address addr; + + if (!sa) sa = &addr.sa; + if (sun->sun_family != AF_UNIX) return (-1); + if (len > sizeof(*sun)) return (-1); + ((char *)sun)[len] = 0; + nn = strlen(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"); ) return (0); } @@ -294,36 +715,25 @@ static int decode_inet_addr(struct sockaddr_in *sin, D( fprintf(stderr, " -- not one of ours\n"); ) return (-1); } - memcpy(buf, sun->sun_path + n + 1, nn - n); - if ((p = strchr(buf, ':')) == 0) { - D( fprintf(stderr, " -- malformed (no port)\n"); ) - return (-1); - } - *p++ = 0; - sin->sin_family = AF_INET; - if (inet_pton(AF_INET, buf, &sin->sin_addr) <= 0) { - D( fprintf(stderr, " -- malformed (bad address `%s')\n", buf); ) - return (-1); - } - port = strtoul(p, &p, 10); - if (*p || port >= 65536) { - D( fprintf(stderr, " -- malformed (port out of range)"); ) - return (-1); - } - sin->sin_port = htons(port); - D( fprintf(stderr, " -> %s:%u\n", - inet_ntop(AF_INET, &sin->sin_addr, buf, sizeof(buf)), - (unsigned)port); ) + if (parse_sockaddr(sa, sun->sun_path + n + 1)) return (-1); + D( fprintf(stderr, " -> %s\n", + present_sockaddr(sa, 0, buf, sizeof(buf))); ) return (0); } -static int fixup_real_ip_socket(int sk) +/* 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. 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, int *tmp) { int nsk; int type; int f, fd; struct sockaddr_un sun; - struct sockaddr_in sin; + address addr; socklen_t len; #define OPTS(_) \ @@ -344,62 +754,65 @@ static int fixup_real_ip_socket(int sk) len = sizeof(sun); if (real_getsockname(sk, SA(&sun), &len)) return (-1); - if (decode_inet_addr(&sin, &sun, len)) + if (decode_inet_addr(&addr.sa, af_hint, &sun, len)) return (0); /* Not one of ours */ len = sizeof(type); if (real_getsockopt(sk, SOL_SOCKET, SO_TYPE, &type, &len) < 0 || - (nsk = real_socket(PF_INET, type, 0)) < 0) + (nsk = real_socket(addr.sa.sa_family, type, 0)) < 0) return (-1); #define FIX(opt, ty) do { \ ty ov_; \ len = sizeof(ov_); \ if (real_getsockopt(sk, SOL_SOCKET, SO_##opt, &ov_, &len) < 0 || \ real_setsockopt(nsk, SOL_SOCKET, SO_##opt, &ov_, len)) { \ - real_close(nsk); \ + close(nsk); \ return (-1); \ } \ } 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) { - real_close(nsk); - return (-1); - } - unlink(sun.sun_path); - real_close(nsk); - if (fcntl(sk, F_SETFD, fd) < 0) { - perror("noip: fixup_real_ip_socket F_SETFD"); - abort(); + 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); + 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) { - struct sockaddr_in sin; + address addr; socklen_t mylen = sizeof(*sun); - if (acl_allows_p(connect_real, SIN(*sa))) { - if (fixup_real_ip_socket(sk)) - return (-1); + if (acl_allows_p(connect_real, *sa)) { + if (fixup_real_ip_socket(sk, (*sa)->sa_family, 0)) return (-1); } else { - if (real_getsockname(sk, SA(sun), &mylen) < 0) - return (-1); + 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]) { - sin.sin_family = AF_INET; - sin.sin_addr.s_addr = INADDR_LOOPBACK; - sin.sin_port = 0; - encode_inet_addr(sun, &sin, WANT_FRESH); - if (real_bind(sk, SA(sun), SUN_LEN(sun))) - return (-1); + 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, SIN(*sa), WANT_EXISTING); + encode_inet_addr(sun, *sa, WANT_EXISTING); *sa = SA(sun); *len = SUN_LEN(sun); } @@ -407,36 +820,46 @@ static int do_implicit_bind(int sk, const struct sockaddr **sa, return (0); } +/* We found the real address SA, with length LEN; if it's a Unix-domain + * address corresponding to a fake socket, convert it to cover up the + * deception. Whatever happens, put the result at FAKE and store its length + * at FAKELEN. + */ static void return_fake_name(struct sockaddr *sa, socklen_t len, struct sockaddr *fake, socklen_t *fakelen) { - struct sockaddr_in sin; + address addr; socklen_t alen; - if (sa->sa_family == AF_UNIX && !decode_inet_addr(&sin, SUN(sa), len)) { - sa = SA(&sin); - len = sizeof(sin); + 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); } alen = len; - if (len > *fakelen) - len = *fakelen; - if (len > 0) - memcpy(fake, sa, len); + if (len > *fakelen) len = *fakelen; + if (len > 0) memcpy(fake, sa, len); *fakelen = alen; } -/* --- Configuration --- */ +/*----- Configuration -----------------------------------------------------*/ +/* Return the process owner's home directory. */ static char *home(void) { char *p; struct passwd *pw; - if ((p = getenv("HOME")) != 0) return (p); - else if ((pw = getpwuid(uid)) != 0) return (pw->pw_dir); - else return "/notexist"; + if (getuid() == uid && + (p = getenv("HOME")) != 0) + return (p); + else if ((pw = getpwuid(uid)) != 0) + return (pw->pw_dir); + else + return "/notexist"; } +/* Return a good temporary directory to use. */ static char *tmpdir(void) { char *p; @@ -446,6 +869,7 @@ static char *tmpdir(void) else return ("/tmp"); } +/* Return the user's name, or at least something distinctive. */ static char *user(void) { static char buf[16]; @@ -461,20 +885,42 @@ static char *user(void) } } +/* Skip P over space characters. */ #define SKIPSPC do { while (*p && isspace(UC(*p))) p++; } while (0) + +/* Set Q to point to the next word following P, null-terminate it, and step P + * past it. */ #define NEXTWORD(q) do { \ SKIPSPC; \ q = p; \ while (*p && !isspace(UC(*p))) p++; \ if (*p) *p++ = 0; \ } while (0) -#define NEXTADDR(q, del) do { \ - SKIPSPC; \ - q = p; \ - while (*p && (*p == '.' || isdigit(UC(*p)))) p++; \ - del = *p; \ - if (*p) *p++ = 0; \ -} while (0) + +/* Set Q to point to the next dotted-quad address, store the ending delimiter + * in DEL, null-terminate it, and step P past it. */ +static void parse_nextaddr(char **pp, char **qq, int *del) +{ + char *p = *pp; + + SKIPSPC; + if (*p == '[') { + p++; SKIPSPC; + *qq = p; + p += strcspn(p, "]"); + if (*p) *p++ = 0; + *del = 0; + } else { + *qq = p; + while (*p && (*p == '.' || isdigit(UC(*p)))) p++; + *del = *p; + if (*p) *p++ = 0; + } + *pp = p; +} + +/* Set Q to point to the next decimal number, store the ending delimiter in + * DEL, null-terminate it, and step P past it. */ #define NEXTNUMBER(q, del) do { \ SKIPSPC; \ q = p; \ @@ -482,132 +928,202 @@ static char *user(void) del = *p; \ if (*p) *p++ = 0; \ } while (0) + +/* Push the character DEL back so we scan it again, unless it's zero + * (end-of-file). */ #define RESCAN(del) do { if (del) *--p = del; } while (0) + +/* Evaluate true if P is pointing to the word KW (and not some longer string + * of which KW is a prefix). */ + #define KWMATCHP(kw) (strncmp(p, kw, sizeof(kw) - 1) == 0 && \ !isalnum(UC(p[sizeof(kw) - 1])) && \ (p += sizeof(kw) - 1)) - + +/* Parse a port list, starting at *PP. Port lists have the form + * [:LOW[-HIGH]]: if omitted, all ports are included; if HIGH is omitted, + * it's as if HIGH = LOW. Store LOW in *MIN, HIGH in *MAX and set *PP to the + * rest of the string. + */ static void parse_ports(char **pp, unsigned short *min, unsigned short *max) { char *p = *pp, *q; int del; SKIPSPC; - if (*p != ':') { - *min = 0; - *max = 0xffff; - } else { + if (*p != ':') + { *min = 0; *max = 0xffff; } + else { p++; - NEXTNUMBER(q, del); - *min = atoi(q); - RESCAN(del); + NEXTNUMBER(q, del); *min = strtoul(q, 0, 0); RESCAN(del); SKIPSPC; - if (*p == '-') { - NEXTNUMBER(q, del); - *max = atoi(q); - RESCAN(del); - } else + if (*p == '-') + { p++; NEXTNUMBER(q, del); *max = strtoul(q, 0, 0); RESCAN(del); } + else *max = *min; } *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_, \ - minaddr_, maxaddr_, minport_, maxport_) do { \ + af_, minaddr_, maxaddr_, minport_, maxport_) do { \ aclnode *a_; \ NEW(a_); \ - a_->act = act_; \ - a_->minaddr = minaddr_; a_->maxaddr = maxaddr_; \ - a_->minport = minport_; a_->maxport = maxport_; \ + 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.. + */ static void parse_acl_line(char **pp, aclnode ***tail) { - struct in_addr addr; - unsigned long minaddr, maxaddr, mask; + ipaddr minaddr, maxaddr; unsigned short minport, maxport; - int i, n; + int i, af, n; int act; int del; char *p = *pp; char *q; - SKIPSPC; - if (*p == '+') act = ALLOW; - else if (*p == '-') act = DENY; - else goto bad; + for (;;) { + SKIPSPC; + if (*p == '+') act = ALLOW; + else if (*p == '-') act = DENY; + else goto bad; - p++; - SKIPSPC; - if (KWMATCHP("any")) { - minaddr = 0; - maxaddr = 0xffffffff; - goto justone; - } else if (KWMATCHP("local")) { - parse_ports(&p, &minport, &maxport); - ACLNODE(*tail, act, 0, 0, minport, maxport); - ACLNODE(*tail, act, 0xffffffff, 0xffffffff, minport, maxport); - for (i = 0; i < n_local_ipaddrs; i++) { - minaddr = ntohl(local_ipaddrs[i].s_addr); - ACLNODE(*tail, act, minaddr, minaddr, minport, maxport); - } - } else { - if (*p == ':') { - minaddr = 0; - maxaddr = 0xffffffff; + p++; + SKIPSPC; + if (KWMATCHP("any")) { + parse_ports(&p, &minport, &maxport); + 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); + } + } else if (KWMATCHP("local")) { + parse_ports(&p, &minport, &maxport); + 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); + } + 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); + } } else { - NEXTADDR(q, del); - if (inet_pton(AF_INET, q, &addr) <= 0) goto bad; - minaddr = ntohl(addr.s_addr); + parse_nextaddr(&p, &q, &del); + af = guess_address_family(q); + if (inet_pton(af, q, &minaddr) <= 0) goto bad; RESCAN(del); SKIPSPC; if (*p == '-') { p++; - NEXTADDR(q, del); - if (inet_pton(AF_INET, q, &addr) <= 0) goto bad; + parse_nextaddr(&p, &q, &del); + if (inet_pton(af, q, &maxaddr) <= 0) goto bad; RESCAN(del); - maxaddr = ntohl(addr.s_addr); } else if (*p == '/') { p++; - NEXTADDR(q, del); - if (strchr(q, '.')) { - if (inet_pton(AF_INET, q, &addr) <= 0) goto bad; - mask = ntohl(addr.s_addr); - } else { - n = atoi(q); - mask = (~0ul << (32 - n)) & 0xffffffff; - } + NEXTNUMBER(q, del); + n = strtoul(q, 0, 0); + maxaddr = minaddr; + mask_address(af, &minaddr, n, 0); + mask_address(af, &maxaddr, n, 1); RESCAN(del); - minaddr &= mask; - maxaddr = minaddr | (mask ^ 0xffffffff); } else maxaddr = minaddr; + parse_ports(&p, &minport, &maxport); + ACLNODE(*tail, act, af, minaddr, maxaddr, minport, maxport); } - justone: - parse_ports(&p, &minport, &maxport); - ACLNODE(*tail, act, minaddr, maxaddr, minport, maxport); + 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 the autoports configuration directive. Syntax is MIN - MAX. */ +static void parse_autoports(char **pp) +{ + char *p = *pp, *q; + unsigned x, y; + int del; + + SKIPSPC; + NEXTNUMBER(q, del); x = strtoul(q, 0, 0); RESCAN(del); + SKIPSPC; + 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, "noip: bad acl spec (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) { FILE *fp; char buf[1024]; size_t n; - char *p, *cmd; - + char *p, *q, *cmd; + Dpid; + + parse_acl_env("NOIP_REALBIND_BEFORE", &bind_tail); + parse_acl_env("NOIP_REALCONNECT_BEFORE", &connect_tail); + if ((p = getenv("NOIP_AUTOPORTS")) != 0) { + p = q = xstrdup(p); + parse_autoports(&q); + free(p); + } if ((p = getenv("NOIP_CONFIG")) == 0) snprintf(p = buf, sizeof(buf), "%s/.noip", home()); - D( fprintf(stderr, "noip: config file: %s\n", p); ) - if ((fp = fopen(p, "r")) == 0) - goto done; + D( fprintf(stderr, "noip(%d): config file: %s\n", pid, p); ) + if ((fp = fopen(p, "r")) == 0) { + D( fprintf(stderr, "noip(%d): couldn't read config: %s\n", + pid, strerror(errno)); ) + goto done; + } while (fgets(buf, sizeof(buf), fp)) { n = strlen(buf); p = buf; @@ -625,6 +1141,8 @@ 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, "autoports") == 0) + parse_autoports(&p); else if (strcmp(cmd, "debug") == 0) debug = *p ? atoi(p) : 1; else @@ -633,81 +1151,185 @@ static void readconfig(void) fclose(fp); done: + parse_acl_env("NOIP_REALBIND", &bind_tail); + parse_acl_env("NOIP_REALCONNECT", &connect_tail); + parse_acl_env("NOIP_REALBIND_AFTER", &bind_tail); + parse_acl_env("NOIP_REALCONNECT_AFTER", &connect_tail); *bind_tail = 0; *connect_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: sockdir: %s\n", sockdir); - 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"); + fprintf(stderr, "noip(%d): realconnect acl:\n", pid); dump_acl(connect_real); ) } -/* --- Hooks --- */ +/*----- 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) { - if (pf == PF_INET) { - pf = PF_UNIX; - proto = 0; + 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; + sk = -1; + } + D( fprintf(stderr, " -> inet; substitute"); ) + pf = PF_UNIX; + proto = 0; + break; + case PF_UNIX: +#ifdef PF_NETLINK + case PF_NETLINK: +#endif + D( fprintf(stderr, " -> safe; permit"); ) + break; } - return real_socket(pf, ty, proto); + 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; + 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 (sa->sa_family == AF_INET) { + 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, SIN(sa))) { - if (fixup_real_ip_socket(sk)) + if (acl_allows_p(bind_real, sa)) { + if (fixup_real_ip_socket(sk, sa->sa_family, 0)) return (-1); } else { - encode_inet_addr(&sun, SIN(sa), WANT_FRESH); + encode_inet_addr(&sun, sa, WANT_FRESH); 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 (sa->sa_family == AF_INET) { + 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 { + D( fprintf(stderr, " -> checking...\n"); ) PRESERVING_ERRNO({ do_implicit_bind(sk, &sa, &len, &sun); }); + D( fprintf(stderr, "noip(%d): CONNECT ...", pid); ) + rc = real_connect(sk, sa, len); + if (rc < 0) { + switch (errno) { + case ENOENT: errno = ECONNREFUSED; break; + } + } } - return real_connect(sk, sa, len); + D( dump_sysresult(rc); ) + return (rc); } 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; - if (to && to->sa_family == AF_INET) { + 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) + 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); }); + 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, @@ -716,57 +1338,91 @@ 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({ - n = real_recvfrom(sk, buf, len, flags, SA(sabuf), &mylen); - if (n < 0) - return (-1); - return_fake_name(SA(sabuf), mylen, from, fromlen); - }); + 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 { + PRESERVING_ERRNO({ + n = real_recvfrom(sk, buf, len, flags, SA(sabuf), &mylen); + if (n >= 0) { + D( fprintf(stderr, " -> converting...\n"); ) + return_fake_name(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); 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; - if (!msg->msg_name) - return real_recvmsg(sk, msg, flags); - PRESERVING_ERRNO({ - sa = SA(msg->msg_name); - len = msg->msg_namelen; - 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); - msg->msg_name = sa; - msg->msg_namelen = len; - }); + D( fprintf(stderr, "noip(%d): RECVMSG sk=%d msg_flags=%d, ...", + pid, sk, msg->msg_flags); ) + + if (!msg->msg_name) { + D( fprintf(stderr, " -> null addr; pass through"); ) + return (real_recvmsg(sk, msg, flags)); + } else { + PRESERVING_ERRNO({ + msg->msg_name = sabuf; + msg->msg_namelen = sizeof(sabuf); + n = real_recvmsg(sk, msg, flags); + if (n >= 0) { + D( fprintf(stderr, " -> converting...\n"); ) + return_fake_name(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); } @@ -774,35 +1430,60 @@ 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_name(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) { + int rc; + Dpid; + + D( fprintf(stderr, "noip(%d): GETSOCKNAME sk=%d", pid, sk); ) 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); + rc = real_getsockname(sk, SA(sabuf), &mylen); + if (rc >= 0) { + D( fprintf(stderr, " -> converting...\n"); ) + return_fake_name(SA(sabuf), mylen, sa, len); + D( fprintf(stderr, "noip(%d): ... GETSOCKNAME", pid); ) + } }); - return (0); + D( dump_addrresult(rc, sa, *len); ) + return (rc); } int getpeername(int sk, struct sockaddr *sa, socklen_t *len) { + int rc; + Dpid; + + D( fprintf(stderr, "noip(%d): GETPEERNAME sk=%d", pid, sk); ) 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); + rc = real_getpeername(sk, SA(sabuf), &mylen); + if (rc >= 0) { + D( fprintf(stderr, " -> converting...\n"); ) + return_fake_name(SA(sabuf), mylen, sa, len); + D( fprintf(stderr, "noip(%d): ... GETPEERNAME", pid); ) + } }); + D( dump_addrresult(rc, sa, *len); ) return (0); } @@ -816,7 +1497,7 @@ int getsockopt(int sk, int lev, int opt, void *p, socklen_t *len) memset(p, 0, *len); return (0); } - return real_getsockopt(sk, lev, opt, p, len); + return (real_getsockopt(sk, lev, opt, p, len)); } int setsockopt(int sk, int lev, int opt, const void *p, socklen_t len) @@ -833,69 +1514,164 @@ int setsockopt(int sk, int lev, int opt, const void *p, socklen_t len) case SO_DETACH_FILTER: return (0); } - return real_setsockopt(sk, lev, opt, p, len); + return (real_setsockopt(sk, lev, opt, p, len)); } -/* --- Initialization --- */ +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. */ static void cleanup_sockdir(void) { DIR *dir; struct dirent *d; + address addr; struct sockaddr_un sun; + struct stat st; + Dpid; - if ((dir = opendir(sockdir)) == 0) - return; + if ((dir = opendir(sockdir)) == 0) return; + sun.sun_family = AF_UNIX; while ((d = readdir(dir)) != 0) { if (d->d_name[0] == '.') continue; snprintf(sun.sun_path, sizeof(sun.sun_path), "%s/%s", sockdir, d->d_name); + 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(%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); } } closedir(dir); } +/* Find the addresses attached to local network interfaces, and remember them + * in a table. + */ static void get_local_ipaddrs(void) { - struct if_nameindex *ifn; - struct ifreq ifr; - int sk; + struct ifaddrs *ifa_head, *ifa; + ipaddr a; int i; - - ifn = if_nameindex(); - if ((sk = real_socket(PF_INET, SOCK_STREAM, 00)) < 0) - return; - for (i = n_local_ipaddrs = 0; - n_local_ipaddrs < MAX_LOCAL_IPADDRS && - ifn[i].if_name && *ifn[i].if_name; - i++) { - strcpy(ifr.ifr_name, ifn[i].if_name); - if (ioctl(sk, SIOCGIFADDR, &ifr) || ifr.ifr_addr.sa_family != AF_INET) + 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; + ifa = ifa->ifa_next) { + if (!ifa->ifa_addr || !family_known_p(ifa->ifa_addr->sa_family)) continue; - local_ipaddrs[n_local_ipaddrs++] = - SIN(&ifr.ifr_addr)->sin_addr; - D( fprintf(stderr, "noip: local addr %s = %s\n", ifn[i].if_name, - inet_ntoa(local_ipaddrs[n_local_ipaddrs - 1])); ) + ipaddr_from_sockaddr(&a, ifa->ifa_addr); + D({ char buf[ADDRBUFSZ]; + 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++) { + if (ifa->ifa_addr->sa_family == local_ipaddrs[i].af && + ipaddr_equal_p(local_ipaddrs[i].af, &a, &local_ipaddrs[i].addr)) { + D( fprintf(stderr, " (duplicate)\n"); ) + goto skip; + } + } + D( fprintf(stderr, "\n"); ) + local_ipaddrs[n_local_ipaddrs].af = ifa->ifa_addr->sa_family; + local_ipaddrs[n_local_ipaddrs].addr = a; + n_local_ipaddrs++; + skip:; + } + freeifaddrs(ifa_head); +} + +/* Print the given message to standard error. Avoids stdio. */ +static void printerr(const char *p) + { if (write(STDERR_FILENO, p, strlen(p))) ; } + +/* Create the socket directory, being careful about permissions. */ +static void create_sockdir(void) +{ + struct stat st; + + if (lstat(sockdir, &st)) { + if (errno == ENOENT) { + if (mkdir(sockdir, 0700)) { + perror("noip: creating socketdir"); + exit(127); + } + if (!lstat(sockdir, &st)) + goto check; + } + perror("noip: checking socketdir"); + exit(127); + } +check: + if (!S_ISDIR(st.st_mode)) { + printerr("noip: bad socketdir: not a directory\n"); + exit(127); + } + if (st.st_uid != uid) { + printerr("noip: bad socketdir: not owner\n"); + exit(127); + } + if (st.st_mode & 077) { + printerr("noip: bad socketdir: not private\n"); + exit(127); } - close(sk); } +/* Initialization function. */ +static void setup(void) __attribute__((constructor)); static void setup(void) { PRESERVING_ERRNO({ char *p; import(); - uid = getuid(); + uid = geteuid(); if ((p = getenv("NOIP_DEBUG")) && atoi(p)) debug = 1; get_local_ipaddrs(); readconfig(); - mkdir(sockdir, 0700); + create_sockdir(); cleanup_sockdir(); }); } + +/*----- That's all, folks -------------------------------------------------*/