/* Copyright (C) 1996-2015 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, see . */ /* 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 #include "nsswitch.h" /* Get implementation for some internal functions. */ #include #include #define RESOLVSORT #if PACKETSZ > 65536 # define MAXPACKET PACKETSZ #else # define MAXPACKET 65536 #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, int32_t *ttlp, char **canonp); static enum nss_status gaih_getanswer (const querybuf *answer1, int anslen1, const querybuf *answer2, int anslen2, const char *qname, struct gaih_addrtuple **pat, char *buffer, size_t buflen, int *errnop, int *h_errnop, int32_t *ttlp); extern enum nss_status _nss_dns_gethostbyname3_r (const char *name, int af, struct hostent *result, char *buffer, size_t buflen, int *errnop, int *h_errnop, int32_t *ttlp, char **canonp); hidden_proto (_nss_dns_gethostbyname3_r) enum nss_status _nss_dns_gethostbyname3_r (const char *name, int af, struct hostent *result, char *buffer, size_t buflen, int *errnop, int *h_errnop, int32_t *ttlp, char **canonp) { union { querybuf *buf; u_char *ptr; } host_buffer; querybuf *orig_host_buffer; char tmp[NS_MAXDNAME]; int size, type, n; const char *cp; int map = 0; int olderr = errno; enum nss_status status; if (__res_maybe_init (&_res, 0) == -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; host_buffer.buf = orig_host_buffer = (querybuf *) alloca (1024); n = __libc_res_nsearch (&_res, name, C_IN, type, host_buffer.buf->buf, 1024, &host_buffer.ptr, NULL, NULL, NULL, NULL); if (n < 0) { switch (errno) { case ESRCH: status = NSS_STATUS_TRYAGAIN; h_errno = TRY_AGAIN; break; /* System has run out of file descriptors. */ case EMFILE: case ENFILE: h_errno = NETDB_INTERNAL; /* Fall through. */ case ECONNREFUSED: case ETIMEDOUT: status = NSS_STATUS_UNAVAIL; break; default: status = NSS_STATUS_NOTFOUND; break; } *h_errnop = h_errno; if (h_errno == TRY_AGAIN) *errnop = EAGAIN; else __set_errno (olderr); /* If we are looking for an 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 = __libc_res_nsearch (&_res, name, C_IN, T_A, host_buffer.buf->buf, host_buffer.buf != orig_host_buffer ? MAXPACKET : 1024, &host_buffer.ptr, NULL, NULL, NULL, NULL); if (n < 0) { if (host_buffer.buf != orig_host_buffer) free (host_buffer.buf); return status; } map = 1; result->h_addrtype = AF_INET; result->h_length = INADDRSZ; } status = getanswer_r (host_buffer.buf, n, name, type, result, buffer, buflen, errnop, h_errnop, map, ttlp, canonp); if (host_buffer.buf != orig_host_buffer) free (host_buffer.buf); return status; } hidden_def (_nss_dns_gethostbyname3_r) 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) { return _nss_dns_gethostbyname3_r (name, af, result, buffer, buflen, errnop, h_errnop, NULL, NULL); } 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_gethostbyname3_r (name, AF_INET6, result, buffer, buflen, errnop, h_errnop, NULL, NULL); if (status == NSS_STATUS_NOTFOUND) status = _nss_dns_gethostbyname3_r (name, AF_INET, result, buffer, buflen, errnop, h_errnop, NULL, NULL); return status; } enum nss_status _nss_dns_gethostbyname4_r (const char *name, struct gaih_addrtuple **pat, char *buffer, size_t buflen, int *errnop, int *herrnop, int32_t *ttlp) { if (__res_maybe_init (&_res, 0) == -1) return NSS_STATUS_UNAVAIL; /* * 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) { char *tmp = alloca (NS_MAXDNAME); const char *cp = res_hostalias (&_res, name, tmp, NS_MAXDNAME); if (cp != NULL) name = cp; } union { querybuf *buf; u_char *ptr; } host_buffer; querybuf *orig_host_buffer; host_buffer.buf = orig_host_buffer = (querybuf *) alloca (2048); u_char *ans2p = NULL; int nans2p = 0; int resplen2 = 0; int ans2p_malloced = 0; int olderr = errno; enum nss_status status; int n = __libc_res_nsearch (&_res, name, C_IN, T_UNSPEC, host_buffer.buf->buf, 2048, &host_buffer.ptr, &ans2p, &nans2p, &resplen2, &ans2p_malloced); if (n >= 0) { status = gaih_getanswer (host_buffer.buf, n, (const querybuf *) ans2p, resplen2, name, pat, buffer, buflen, errnop, herrnop, ttlp); } else { switch (errno) { case ESRCH: status = NSS_STATUS_TRYAGAIN; h_errno = TRY_AGAIN; break; /* System has run out of file descriptors. */ case EMFILE: case ENFILE: h_errno = NETDB_INTERNAL; /* Fall through. */ case ECONNREFUSED: case ETIMEDOUT: status = NSS_STATUS_UNAVAIL; break; default: status = NSS_STATUS_NOTFOUND; break; } *herrnop = h_errno; if (h_errno == TRY_AGAIN) *errnop = EAGAIN; else __set_errno (olderr); } /* Check whether ans2p was separately allocated. */ if (ans2p_malloced) free (ans2p); if (host_buffer.buf != orig_host_buffer) free (host_buffer.buf); return status; } extern enum nss_status _nss_dns_gethostbyaddr2_r (const void *addr, socklen_t len, int af, struct hostent *result, char *buffer, size_t buflen, int *errnop, int *h_errnop, int32_t *ttlp); hidden_proto (_nss_dns_gethostbyaddr2_r) enum nss_status _nss_dns_gethostbyaddr2_r (const void *addr, socklen_t len, int af, struct hostent *result, char *buffer, size_t buflen, int *errnop, int *h_errnop, int32_t *ttlp) { 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; union { querybuf *buf; u_char *ptr; } host_buffer; querybuf *orig_host_buffer; char qbuf[MAXDNAME+1], *qp = NULL; size_t size; int n, status; int olderr = errno; uintptr_t pad = -(uintptr_t) buffer % __alignof__ (struct host_data); buffer += pad; buflen = buflen > pad ? buflen - pad : 0; if (__glibc_unlikely (buflen < sizeof (struct host_data))) { *errnop = ERANGE; *h_errnop = NETDB_INTERNAL; return NSS_STATUS_TRYAGAIN; } host_data = (struct host_data *) buffer; if (__res_maybe_init (&_res, 0) == -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; } host_buffer.buf = orig_host_buffer = (querybuf *) alloca (1024); 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: /* Only lookup with the byte string format if the user wants it. */ if (__glibc_unlikely (_res.options & RES_USEBSTRING)) { qp = stpcpy (qbuf, "\\[x"); for (n = 0; n < IN6ADDRSZ; ++n) qp += sprintf (qp, "%02hhx", uaddr[n]); strcpy (qp, "].ip6.arpa"); n = __libc_res_nquery (&_res, qbuf, C_IN, T_PTR, host_buffer.buf->buf, 1024, &host_buffer.ptr, NULL, NULL, NULL, NULL); if (n >= 0) goto got_it_already; } qp = qbuf; for (n = IN6ADDRSZ - 1; n >= 0; n--) { static const char nibblechar[16] = "0123456789abcdef"; *qp++ = nibblechar[uaddr[n] & 0xf]; *qp++ = '.'; *qp++ = nibblechar[(uaddr[n] >> 4) & 0xf]; *qp++ = '.'; } strcpy(qp, "ip6.arpa"); break; default: /* Cannot happen. */ break; } n = __libc_res_nquery (&_res, qbuf, C_IN, T_PTR, host_buffer.buf->buf, 1024, &host_buffer.ptr, NULL, NULL, NULL, NULL); if (n < 0 && af == AF_INET6 && (_res.options & RES_NOIP6DOTINT) == 0) { strcpy (qp, "ip6.int"); n = __libc_res_nquery (&_res, qbuf, C_IN, T_PTR, host_buffer.buf->buf, host_buffer.buf != orig_host_buffer ? MAXPACKET : 1024, &host_buffer.ptr, NULL, NULL, NULL, NULL); } if (n < 0) { *h_errnop = h_errno; __set_errno (olderr); if (host_buffer.buf != orig_host_buffer) free (host_buffer.buf); return errno == ECONNREFUSED ? NSS_STATUS_UNAVAIL : NSS_STATUS_NOTFOUND; } got_it_already: status = getanswer_r (host_buffer.buf, n, qbuf, T_PTR, result, buffer, buflen, errnop, h_errnop, 0 /* XXX */, ttlp, NULL); if (host_buffer.buf != orig_host_buffer) free (host_buffer.buf); if (status != NSS_STATUS_SUCCESS) 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; } hidden_def (_nss_dns_gethostbyaddr2_r) 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) { return _nss_dns_gethostbyaddr2_r (addr, len, af, result, buffer, buflen, errnop, h_errnop, NULL); } #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, int32_t *ttlp, char **canonp) { struct host_data { char *aliases[MAX_NR_ALIASES]; unsigned char host_addr[16]; /* IPv4 or IPv6 */ char *h_addr_ptrs[0]; } *host_data; int linebuflen; 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; uintptr_t pad = -(uintptr_t) buffer % __alignof__ (struct host_data); buffer += pad; buflen = buflen > pad ? buflen - pad : 0; if (__glibc_unlikely (buflen < sizeof (struct host_data))) { /* The buffer is too small. */ too_small: *errnop = ERANGE; *h_errnop = NETDB_INTERNAL; return NSS_STATUS_TRYAGAIN; } host_data = (struct host_data *) buffer; linebuflen = buflen - sizeof (struct host_data); if (buflen - sizeof (struct host_data) != linebuflen) linebuflen = INT_MAX; 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; 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 (__builtin_expect (n < 0 || ((*name_ok) (bp) == 0 && (errno = EBADMSG)), 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 (__glibc_unlikely (n < 0 || (*name_ok) (bp) == 0)) { ++had_error; continue; } cp += n; /* name */ if (__glibc_unlikely (cp + 10 > end_of_message)) { ++had_error; continue; } type = __ns_get16 (cp); cp += INT16SZ; /* type */ class = __ns_get16 (cp); cp += INT16SZ; /* class */ int32_t ttl = __ns_get32 (cp); cp += INT32SZ; /* TTL */ n = __ns_get16 (cp); cp += INT16SZ; /* len */ if (__glibc_unlikely (class != C_IN)) { /* XXX - debug? syslog? */ cp += n; continue; /* XXX - had_error++ ? */ } if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) { /* A CNAME could also have a TTL entry. */ if (ttlp != NULL && ttl < *ttlp) *ttlp = ttl; if (ap >= &host_data->aliases[MAX_NR_ALIASES - 1]) continue; n = dn_expand (answer->buf, end_of_message, cp, tbuf, sizeof tbuf); if (__glibc_unlikely (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 (__glibc_unlikely (n > linebuflen)) 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 (__glibc_unlikely (n < 0 || res_dnok (tbuf) == 0)) { ++had_error; continue; } cp += n; /* Get canonical name. */ n = strlen (tbuf) + 1; /* For the \0. */ if (__glibc_unlikely (n > linebuflen)) 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 (__glibc_unlikely (type != qtype)) { 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 (__glibc_unlikely (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 (__glibc_unlikely (n < 0 || res_hnok (bp) == 0)) { ++had_error; break; } /* bind would put multiple PTR records as aliases, but we don't do that. */ result->h_name = bp; if (have_to_map) { n = strlen (bp) + 1; /* for the \0 */ if (__glibc_unlikely (n >= MAXHOSTNAMELEN)) { ++had_error; break; } bp += n; linebuflen -= n; if (map_v4v6_hostent (result, &bp, &linebuflen)) goto too_small; } *h_errnop = NETDB_SUCCESS; return NSS_STATUS_SUCCESS; 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) { int nn; /* We compose a single hostent out of the entire chain of entries, so the TTL of the hostent is essentially the lowest TTL in the chain. */ if (ttlp != NULL && ttl < *ttlp) *ttlp = ttl; if (canonp != NULL) *canonp = bp; 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 (__glibc_unlikely (n > linebuflen)) 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) if (map_v4v6_hostent (result, &bp, &linebuflen)) goto too_small; *h_errnop = NETDB_SUCCESS; return NSS_STATUS_SUCCESS; } no_recovery: *h_errnop = NO_RECOVERY; *errnop = ENOENT; /* Special case here: if the resolver sent a result but it only contains a CNAME while we are looking for a T_A or T_AAAA record, we fail with NOTFOUND instead of TRYAGAIN. */ return ((qtype == T_A || qtype == T_AAAA) && ap != host_data->aliases ? NSS_STATUS_NOTFOUND : NSS_STATUS_TRYAGAIN); } static enum nss_status gaih_getanswer_slice (const querybuf *answer, int anslen, const char *qname, struct gaih_addrtuple ***patp, char **bufferp, size_t *buflenp, int *errnop, int *h_errnop, int32_t *ttlp, int *firstp) { char *buffer = *bufferp; size_t buflen = *buflenp; struct gaih_addrtuple **pat = *patp; const HEADER *hp = &answer->hdr; int ancount = ntohs (hp->ancount); int qdcount = ntohs (hp->qdcount); const u_char *cp = answer->buf + HFIXEDSZ; const u_char *end_of_message = answer->buf + anslen; if (__glibc_unlikely (qdcount != 1)) { *h_errnop = NO_RECOVERY; return NSS_STATUS_UNAVAIL; } u_char packtmp[NS_MAXCDNAME]; int n = __ns_name_unpack (answer->buf, end_of_message, cp, packtmp, sizeof packtmp); /* We unpack the name to check it for validity. But we do not need it later. */ if (n != -1 && __ns_name_ntop (packtmp, buffer, buflen) == -1) { if (__builtin_expect (errno, 0) == EMSGSIZE) { too_small: *errnop = ERANGE; *h_errnop = NETDB_INTERNAL; return NSS_STATUS_TRYAGAIN; } n = -1; } if (__builtin_expect (n < 0 || (res_hnok (buffer) == 0 && (errno = EBADMSG)), 0)) { *errnop = errno; *h_errnop = NO_RECOVERY; return NSS_STATUS_UNAVAIL; } cp += n + QFIXEDSZ; int haveanswer = 0; int had_error = 0; char *canon = NULL; char *h_name = NULL; int h_namelen = 0; if (ancount == 0) return NSS_STATUS_NOTFOUND; while (ancount-- > 0 && cp < end_of_message && had_error == 0) { n = __ns_name_unpack (answer->buf, end_of_message, cp, packtmp, sizeof packtmp); if (n != -1 && (h_namelen = __ns_name_ntop (packtmp, buffer, buflen)) == -1) { if (__builtin_expect (errno, 0) == EMSGSIZE) goto too_small; n = -1; } if (__glibc_unlikely (n < 0 || res_hnok (buffer) == 0)) { ++had_error; continue; } if (*firstp && canon == NULL) { h_name = buffer; buffer += h_namelen; buflen -= h_namelen; } cp += n; /* name */ if (__glibc_unlikely (cp + 10 > end_of_message)) { ++had_error; continue; } int type = __ns_get16 (cp); cp += INT16SZ; /* type */ int class = __ns_get16 (cp); cp += INT16SZ; /* class */ int32_t ttl = __ns_get32 (cp); cp += INT32SZ; /* TTL */ n = __ns_get16 (cp); cp += INT16SZ; /* len */ if (class != C_IN) { cp += n; continue; } if (type == T_CNAME) { char tbuf[MAXDNAME]; /* A CNAME could also have a TTL entry. */ if (ttlp != NULL && ttl < *ttlp) *ttlp = ttl; n = dn_expand (answer->buf, end_of_message, cp, tbuf, sizeof tbuf); if (__glibc_unlikely (n < 0 || res_hnok (tbuf) == 0)) { ++had_error; continue; } cp += n; if (*firstp) { /* Reclaim buffer space. */ if (h_name + h_namelen == buffer) { buffer = h_name; buflen += h_namelen; } n = strlen (tbuf) + 1; if (__glibc_unlikely (n > buflen)) goto too_small; if (__glibc_unlikely (n >= MAXHOSTNAMELEN)) { ++had_error; continue; } canon = buffer; buffer = __mempcpy (buffer, tbuf, n); buflen -= n; h_namelen = 0; } continue; } #if 1 // We should not see any types other than those explicitly listed // below. Some types sent by server seem missing, though. Just // collect the data for now. if (__glibc_unlikely (type != T_A && type != T_AAAA)) #else if (__builtin_expect (type == T_SIG, 0) || __builtin_expect (type == T_KEY, 0) || __builtin_expect (type == T_NXT, 0) || __builtin_expect (type == T_PTR, 0) || __builtin_expect (type == T_DNAME, 0)) #endif { /* We don't support DNSSEC yet. For now, ignore the record and send a low priority message to syslog. We also don't expect T_PTR or T_DNAME messages. */ syslog (LOG_DEBUG | LOG_AUTH, "getaddrinfo*.gaih_getanswer: got type \"%s\"", p_type (type)); cp += n; continue; } if (type != T_A && type != T_AAAA) abort (); if (*pat == NULL) { uintptr_t pad = (-(uintptr_t) buffer % __alignof__ (struct gaih_addrtuple)); buffer += pad; buflen = buflen > pad ? buflen - pad : 0; if (__builtin_expect (buflen < sizeof (struct gaih_addrtuple), 0)) goto too_small; *pat = (struct gaih_addrtuple *) buffer; buffer += sizeof (struct gaih_addrtuple); buflen -= sizeof (struct gaih_addrtuple); } (*pat)->name = NULL; (*pat)->next = NULL; if (*firstp) { /* We compose a single hostent out of the entire chain of entries, so the TTL of the hostent is essentially the lowest TTL in the chain. */ if (ttlp != NULL && ttl < *ttlp) *ttlp = ttl; (*pat)->name = canon ?: h_name; *firstp = 0; } (*pat)->family = type == T_A ? AF_INET : AF_INET6; if (__builtin_expect ((type == T_A && n != INADDRSZ) || (type == T_AAAA && n != IN6ADDRSZ), 0)) { ++had_error; continue; } memcpy ((*pat)->addr, cp, n); cp += n; (*pat)->scopeid = 0; pat = &((*pat)->next); haveanswer = 1; } if (haveanswer) { *patp = pat; *bufferp = buffer; *buflenp = buflen; *h_errnop = NETDB_SUCCESS; return NSS_STATUS_SUCCESS; } /* Special case here: if the resolver sent a result but it only contains a CNAME while we are looking for a T_A or T_AAAA record, we fail with NOTFOUND instead of TRYAGAIN. */ return canon == NULL ? NSS_STATUS_TRYAGAIN : NSS_STATUS_NOTFOUND; } static enum nss_status gaih_getanswer (const querybuf *answer1, int anslen1, const querybuf *answer2, int anslen2, const char *qname, struct gaih_addrtuple **pat, char *buffer, size_t buflen, int *errnop, int *h_errnop, int32_t *ttlp) { int first = 1; enum nss_status status = NSS_STATUS_NOTFOUND; if (anslen1 > 0) status = gaih_getanswer_slice(answer1, anslen1, qname, &pat, &buffer, &buflen, errnop, h_errnop, ttlp, &first); if ((status == NSS_STATUS_SUCCESS || status == NSS_STATUS_NOTFOUND || (status == NSS_STATUS_TRYAGAIN /* We want to look at the second answer in case of an NSS_STATUS_TRYAGAIN only if the error is non-recoverable, i.e. *h_errnop is NO_RECOVERY. If not, and if the failure was due to an insufficient buffer (ERANGE), then we need to drop the results and pass on the NSS_STATUS_TRYAGAIN to the caller so that it can repeat the query with a larger buffer. */ && (*errnop != ERANGE || *h_errnop == NO_RECOVERY))) && answer2 != NULL && anslen2 > 0) { enum nss_status status2 = gaih_getanswer_slice(answer2, anslen2, qname, &pat, &buffer, &buflen, errnop, h_errnop, ttlp, &first); if (status != NSS_STATUS_SUCCESS && status2 != NSS_STATUS_NOTFOUND) status = status2; } return status; }