/* Copyright (C) 1996-2000, 2001 Free Software Foundation, Inc. This file is part of the GNU C Library. Extended from original form by Ulrich Drepper , 1996. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. The GNU C Library is 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 Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. */ /* Parts of this file are plain copies of the file `gethtnamadr.c' from the bind package and it has the following copyright. */ /* * ++Copyright++ 1985, 1988, 1993 * - * Copyright (c) 1985, 1988, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * - * Portions Copyright (c) 1993 by Digital Equipment Corporation. * * Permission to use, copy, modify, and distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies, and that * the name of Digital Equipment Corporation not be used in advertising or * publicity pertaining to distribution of the document or software without * specific, written prior permission. * * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS * SOFTWARE. * - * --Copyright-- */ #include #include #include #include #include #include #include #include #include "nsswitch.h" /* Get implementation for some internal functions. */ #include #include #define RESOLVSORT /* Maximum number of aliases we allow. */ #define MAX_NR_ALIASES 48 #define MAX_NR_ADDRS 48 #if PACKETSZ > 1024 # define MAXPACKET PACKETSZ #else # define MAXPACKET 1024 #endif /* As per RFC 1034 and 1035 a host name cannot exceed 255 octets in length. */ #ifdef MAXHOSTNAMELEN # undef MAXHOSTNAMELEN #endif #define MAXHOSTNAMELEN 256 static const char AskedForGot[] = "\ gethostby*.getanswer: asked for \"%s\", got \"%s\""; /* We need this time later. */ typedef union querybuf { HEADER hdr; u_char buf[MAXPACKET]; } querybuf; /* These functions are defined in res_comp.c. */ #define NS_MAXCDNAME 255 /* maximum compressed domain name */ extern int __ns_name_ntop (const u_char *, char *, size_t); extern int __ns_name_unpack (const u_char *, const u_char *, const u_char *, u_char *, size_t); static enum nss_status getanswer_r (const querybuf *answer, int anslen, const char *qname, int qtype, struct hostent *result, char *buffer, size_t buflen, int *errnop, int *h_errnop, int map); enum nss_status _nss_dns_gethostbyname2_r (const char *name, int af, struct hostent *result, char *buffer, size_t buflen, int *errnop, int *h_errnop) { querybuf host_buffer; char tmp[NS_MAXDNAME]; int size, type, n; const char *cp; int map = 0; if ((_res.options & RES_INIT) == 0 && __res_ninit (&_res) == -1) return NSS_STATUS_UNAVAIL; switch (af) { case AF_INET: size = INADDRSZ; type = T_A; break; case AF_INET6: size = IN6ADDRSZ; type = T_AAAA; break; default: *h_errnop = NO_DATA; *errnop = EAFNOSUPPORT; return NSS_STATUS_UNAVAIL; } result->h_addrtype = af; result->h_length = size; /* * if there aren't any dots, it could be a user-level alias. * this is also done in res_query() since we are not the only * function that looks up host names. */ if (strchr (name, '.') == NULL && (cp = res_hostalias (&_res, name, tmp, sizeof (tmp))) != NULL) name = cp; n = res_nsearch (&_res, name, C_IN, type, host_buffer.buf, sizeof (host_buffer.buf)); if (n < 0) { enum nss_status status = (errno == ECONNREFUSED ? NSS_STATUS_UNAVAIL : NSS_STATUS_NOTFOUND); *h_errnop = h_errno; *errnop = h_errno == TRY_AGAIN ? EAGAIN : ENOENT; /* If we are looking for a IPv6 address and mapping is enabled by having the RES_USE_INET6 bit in _res.options set, we try another lookup. */ if (af == AF_INET6 && (_res.options & RES_USE_INET6)) n = res_nsearch (&_res, name, C_IN, T_A, host_buffer.buf, sizeof (host_buffer.buf)); if (n < 0) return status; map = 1; result->h_addrtype = AF_INET; result->h_length = INADDRSZ;; } return getanswer_r (&host_buffer, n, name, type, result, buffer, buflen, errnop, h_errnop, map); } enum nss_status _nss_dns_gethostbyname_r (const char *name, struct hostent *result, char *buffer, size_t buflen, int *errnop, int *h_errnop) { enum nss_status status = NSS_STATUS_NOTFOUND; if (_res.options & RES_USE_INET6) status = _nss_dns_gethostbyname2_r (name, AF_INET6, result, buffer, buflen, errnop, h_errnop); if (status == NSS_STATUS_NOTFOUND) status = _nss_dns_gethostbyname2_r (name, AF_INET, result, buffer, buflen, errnop, h_errnop); return status; } enum nss_status _nss_dns_gethostbyaddr_r (const void *addr, socklen_t len, int af, struct hostent *result, char *buffer, size_t buflen, int *errnop, int *h_errnop) { static const u_char mapped[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0xff,0xff }; static const u_char tunnelled[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0,0 }; static const u_char v6local[] = { 0,0, 0,1 }; const u_char *uaddr = (const u_char *)addr; struct host_data { char *aliases[MAX_NR_ALIASES]; unsigned char host_addr[16]; /* IPv4 or IPv6 */ char *h_addr_ptrs[MAX_NR_ADDRS + 1]; char linebuffer[0]; } *host_data = (struct host_data *) buffer; querybuf host_buffer; char qbuf[MAXDNAME+1], *qp; size_t size; int n, status; if ((_res.options & RES_INIT) == 0 && __res_ninit (&_res) == -1) return NSS_STATUS_UNAVAIL; if (af == AF_INET6 && len == IN6ADDRSZ && (memcmp (uaddr, mapped, sizeof mapped) == 0 || (memcmp (uaddr, tunnelled, sizeof tunnelled) == 0 && memcmp (&uaddr[sizeof tunnelled], v6local, sizeof v6local)))) { /* Unmap. */ addr += sizeof mapped; uaddr += sizeof mapped; af = AF_INET; len = INADDRSZ; } switch (af) { case AF_INET: size = INADDRSZ; break; case AF_INET6: size = IN6ADDRSZ; break; default: *errnop = EAFNOSUPPORT; *h_errnop = NETDB_INTERNAL; return NSS_STATUS_UNAVAIL; } if (size > len) { *errnop = EAFNOSUPPORT; *h_errnop = NETDB_INTERNAL; return NSS_STATUS_UNAVAIL; } switch (af) { case AF_INET: sprintf (qbuf, "%u.%u.%u.%u.in-addr.arpa", (uaddr[3] & 0xff), (uaddr[2] & 0xff), (uaddr[1] & 0xff), (uaddr[0] & 0xff)); break; case AF_INET6: qp = qbuf; for (n = IN6ADDRSZ - 1; n >= 0; n--) qp += sprintf (qp, "%x.%x.", uaddr[n] & 0xf, (uaddr[n] >> 4) & 0xf); strcpy (qp, "ip6.arpa"); break; default: /* Cannot happen. */ break; } n = res_nquery (&_res, qbuf, C_IN, T_PTR, (u_char *)host_buffer.buf, sizeof host_buffer); if (n < 0 && af == AF_INET6) { strcpy (qp, "ip6.int"); n = res_nquery (&_res, qbuf, C_IN, T_PTR, (u_char *)host_buffer.buf, sizeof host_buffer); } if (n < 0) { *h_errnop = h_errno; *errnop = errno; return errno == ECONNREFUSED ? NSS_STATUS_UNAVAIL : NSS_STATUS_NOTFOUND; } status = getanswer_r (&host_buffer, n, qbuf, T_PTR, result, buffer, buflen, errnop, h_errnop, 0 /* XXX */); if (status != NSS_STATUS_SUCCESS) { *h_errnop = h_errno; *errnop = errno; return status; } #ifdef SUNSECURITY This is not implemented because it is not possible to use the current source from bind in a multi-threaded program. #endif result->h_addrtype = af; result->h_length = len; memcpy (host_data->host_addr, addr, len); host_data->h_addr_ptrs[0] = (char *) host_data->host_addr; host_data->h_addr_ptrs[1] = NULL; #if 0 /* XXX I think this is wrong. Why should an IPv4 address be converted to IPv6 if the user explicitly asked for IPv4? */ if (af == AF_INET && (_res.options & RES_USE_INET6)) { map_v4v6_address ((char *) host_data->host_addr, (char *) host_data->host_addr); result->h_addrtype = AF_INET6; result->h_length = IN6ADDRSZ; } #endif *h_errnop = NETDB_SUCCESS; return NSS_STATUS_SUCCESS; } #ifdef RESOLVSORT static void addrsort (char **ap, int num); static void addrsort (char **ap, int num) { int i, j; char **p; short aval[MAX_NR_ADDRS]; int needsort = 0; p = ap; if (num > MAX_NR_ADDRS) num = MAX_NR_ADDRS; for (i = 0; i < num; i++, p++) { for (j = 0 ; (unsigned)j < _res.nsort; j++) if (_res.sort_list[j].addr.s_addr == (((struct in_addr *)(*p))->s_addr & _res.sort_list[j].mask)) break; aval[i] = j; if (needsort == 0 && i > 0 && j < aval[i-1]) needsort = i; } if (!needsort) return; while (needsort++ < num) for (j = needsort - 2; j >= 0; j--) if (aval[j] > aval[j+1]) { char *hp; i = aval[j]; aval[j] = aval[j+1]; aval[j+1] = i; hp = ap[j]; ap[j] = ap[j+1]; ap[j+1] = hp; } else break; } #endif static enum nss_status getanswer_r (const querybuf *answer, int anslen, const char *qname, int qtype, struct hostent *result, char *buffer, size_t buflen, int *errnop, int *h_errnop, int map) { struct host_data { char *aliases[MAX_NR_ALIASES]; unsigned char host_addr[16]; /* IPv4 or IPv6 */ char *h_addr_ptrs[0]; } *host_data = (struct host_data *) buffer; int linebuflen = buflen - sizeof (struct host_data); register const HEADER *hp; const u_char *end_of_message, *cp; int n, ancount, qdcount; int haveanswer, had_error; char *bp, **ap, **hap; char tbuf[MAXDNAME]; const char *tname; int (*name_ok) (const char *); u_char packtmp[NS_MAXCDNAME]; int have_to_map = 0; if (__builtin_expect (linebuflen, 0) < 0) { /* The buffer is too small. */ too_small: *errnop = ERANGE; *h_errnop = NETDB_INTERNAL; return NSS_STATUS_TRYAGAIN; } tname = qname; result->h_name = NULL; end_of_message = answer->buf + anslen; switch (qtype) { case T_A: case T_AAAA: name_ok = res_hnok; break; case T_PTR: name_ok = res_dnok; break; default: *errnop = ENOENT; return NSS_STATUS_UNAVAIL; /* XXX should be abort(); */ } /* * find first satisfactory answer */ hp = &answer->hdr; ancount = ntohs (hp->ancount); qdcount = ntohs (hp->qdcount); cp = answer->buf + HFIXEDSZ; if (__builtin_expect (qdcount, 1) != 1) { *h_errnop = NO_RECOVERY; *errnop = ENOENT; return NSS_STATUS_UNAVAIL; } if (sizeof (struct host_data) + (ancount + 1) * sizeof (char *) >= buflen) goto too_small; bp = (char *) &host_data->h_addr_ptrs[ancount + 1]; linebuflen -= (ancount + 1) * sizeof (char *); n = __ns_name_unpack (answer->buf, end_of_message, cp, packtmp, sizeof packtmp); if (n != -1 && __ns_name_ntop (packtmp, bp, linebuflen) == -1) { if (__builtin_expect (errno, 0) == EMSGSIZE) goto too_small; n = -1; } if (n > 0 && bp[0] == '.') bp[0] = '\0'; if (n < 0 || (*name_ok) (bp) == 0) { *errnop = errno; *h_errnop = NO_RECOVERY; return NSS_STATUS_UNAVAIL; } cp += n + QFIXEDSZ; if (qtype == T_A || qtype == T_AAAA) { /* res_send() has already verified that the query name is the * same as the one we sent; this just gets the expanded name * (i.e., with the succeeding search-domain tacked on). */ n = strlen (bp) + 1; /* for the \0 */ if (n >= MAXHOSTNAMELEN) { *h_errnop = NO_RECOVERY; *errnop = ENOENT; return NSS_STATUS_TRYAGAIN; } result->h_name = bp; bp += n; linebuflen -= n; if (linebuflen < 0) goto too_small; /* The qname can be abbreviated, but h_name is now absolute. */ qname = result->h_name; } ap = host_data->aliases; *ap = NULL; result->h_aliases = host_data->aliases; hap = host_data->h_addr_ptrs; *hap = NULL; result->h_addr_list = host_data->h_addr_ptrs; haveanswer = 0; had_error = 0; while (ancount-- > 0 && cp < end_of_message && had_error == 0) { int type, class; n = __ns_name_unpack (answer->buf, end_of_message, cp, packtmp, sizeof packtmp); if (n != -1 && __ns_name_ntop (packtmp, bp, linebuflen) == -1) { if (__builtin_expect (errno, 0) == EMSGSIZE) goto too_small; n = -1; } if (n < 0 || (*name_ok) (bp) == 0) { ++had_error; continue; } cp += n; /* name */ type = ns_get16 (cp); cp += INT16SZ; /* type */ class = ns_get16 (cp); cp += INT16SZ + INT32SZ; /* class, TTL */ n = ns_get16 (cp); cp += INT16SZ; /* len */ if (class != C_IN) { /* XXX - debug? syslog? */ cp += n; continue; /* XXX - had_error++ ? */ } if ((qtype ==T_A || qtype == T_AAAA) && type == T_CNAME) { if (ap >= &host_data->aliases[MAX_NR_ALIASES - 1]) continue; n = dn_expand (answer->buf, end_of_message, cp, tbuf, sizeof tbuf); if (n < 0 || (*name_ok) (tbuf) == 0) { ++had_error; continue; } cp += n; /* Store alias. */ *ap++ = bp; n = strlen (bp) + 1; /* For the \0. */ if (__builtin_expect (n, 0) >= MAXHOSTNAMELEN) { ++had_error; continue; } bp += n; linebuflen -= n; /* Get canonical name. */ n = strlen (tbuf) + 1; /* For the \0. */ if (__builtin_expect (n > linebuflen, 0)) goto too_small; if (__builtin_expect (n, 0) >= MAXHOSTNAMELEN) { ++had_error; continue; } result->h_name = bp; bp = __mempcpy (bp, tbuf, n); /* Cannot overflow. */ linebuflen -= n; continue; } if (qtype == T_PTR && type == T_CNAME) { n = dn_expand (answer->buf, end_of_message, cp, tbuf, sizeof tbuf); if (n < 0 || res_dnok (tbuf) == 0) { ++had_error; continue; } cp += n; /* Get canonical name. */ n = strlen (tbuf) + 1; /* For the \0. */ if (__builtin_expect (n > linebuflen, 0)) goto too_small; if (__builtin_expect (n, 0) >= MAXHOSTNAMELEN) { ++had_error; continue; } tname = bp; bp = __mempcpy (bp, tbuf, n); /* Cannot overflow. */ linebuflen -= n; continue; } if (__builtin_expect (type == T_SIG, 0) || __builtin_expect (type == T_KEY, 0) || __builtin_expect (type == T_NXT, 0)) { /* We don't support DNSSEC yet. For now, ignore the record and send a low priority message to syslog. */ syslog (LOG_DEBUG | LOG_AUTH, "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"", qname, p_class (C_IN), p_type(qtype), p_type (type)); cp += n; continue; } if (type == T_A && qtype == T_AAAA && map) have_to_map = 1; else if (__builtin_expect (type != qtype, 0)) { syslog (LOG_NOTICE | LOG_AUTH, "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"", qname, p_class (C_IN), p_type (qtype), p_type (type)); cp += n; continue; /* XXX - had_error++ ? */ } switch (type) { case T_PTR: if (__strcasecmp (tname, bp) != 0) { syslog (LOG_NOTICE | LOG_AUTH, AskedForGot, qname, bp); cp += n; continue; /* XXX - had_error++ ? */ } n = __ns_name_unpack (answer->buf, end_of_message, cp, packtmp, sizeof packtmp); if (n != -1 && __ns_name_ntop (packtmp, bp, linebuflen) == -1) { if (__builtin_expect (errno, 0) == EMSGSIZE) goto too_small; n = -1; } if (n < 0 || res_hnok (bp) == 0) { ++had_error; break; } #if MULTI_PTRS_ARE_ALIASES cp += n; if (haveanswer == 0) result->h_name = bp; else if (ap < &host_data->aliases[MAXALIASES-1]) *ap++ = bp; else n = -1; if (n != -1) { n = strlen (bp) + 1; /* for the \0 */ if (__builtin_expect (n, 0) >= MAXHOSTNAMELEN) { ++had_error; break; } bp += n; linebuflen -= n; } break; #else result->h_name = bp; if (have_to_map) { n = strlen (bp) + 1; /* for the \0 */ if (n >= MAXHOSTNAMELEN) { ++had_error; break; } bp += n; linebuflen -= n; map_v4v6_hostent (result, &bp, &linebuflen); } *h_errnop = NETDB_SUCCESS; return NSS_STATUS_SUCCESS; #endif case T_A: case T_AAAA: if (__builtin_expect (strcasecmp (result->h_name, bp), 0) != 0) { syslog (LOG_NOTICE | LOG_AUTH, AskedForGot, result->h_name, bp); cp += n; continue; /* XXX - had_error++ ? */ } if (n != result->h_length) { cp += n; continue; } if (!haveanswer) { register int nn; result->h_name = bp; nn = strlen (bp) + 1; /* for the \0 */ bp += nn; linebuflen -= nn; } linebuflen -= sizeof (align) - ((u_long) bp % sizeof (align)); bp += sizeof (align) - ((u_long) bp % sizeof (align)); if (__builtin_expect (n > linebuflen, 0)) goto too_small; bp = __mempcpy (*hap++ = bp, cp, n); cp += n; linebuflen -= n; break; default: abort (); } if (had_error == 0) ++haveanswer; } if (haveanswer > 0) { *ap = NULL; *hap = NULL; #if defined RESOLVSORT /* * Note: we sort even if host can take only one address * in its return structures - should give it the "best" * address in that case, not some random one */ if (_res.nsort && haveanswer > 1 && qtype == T_A) addrsort (host_data->h_addr_ptrs, haveanswer); #endif /*RESOLVSORT*/ if (result->h_name == NULL) { n = strlen (qname) + 1; /* For the \0. */ if (n > linebuflen) goto too_small; if (n >= MAXHOSTNAMELEN) goto no_recovery; result->h_name = bp; bp = __mempcpy (bp, qname, n); /* Cannot overflow. */ linebuflen -= n; } if (have_to_map) map_v4v6_hostent (result, &bp, &linebuflen); *h_errnop = NETDB_SUCCESS; return NSS_STATUS_SUCCESS; } no_recovery: *h_errnop = NO_RECOVERY; *errnop = ENOENT; return NSS_STATUS_TRYAGAIN; }