diff options
Diffstat (limited to 'resolv/nss_dns/dns-host.c')
| -rw-r--r-- | resolv/nss_dns/dns-host.c | 1333 |
1 files changed, 0 insertions, 1333 deletions
diff --git a/resolv/nss_dns/dns-host.c b/resolv/nss_dns/dns-host.c deleted file mode 100644 index f121aa3de7..0000000000 --- a/resolv/nss_dns/dns-host.c +++ /dev/null @@ -1,1333 +0,0 @@ -/* Copyright (C) 1996-2017 Free Software Foundation, Inc. - This file is part of the GNU C Library. - Extended from original form by Ulrich Drepper <drepper@cygnus.com>, 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 - <http://www.gnu.org/licenses/>. */ - -/* 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 <assert.h> -#include <ctype.h> -#include <errno.h> -#include <netdb.h> -#include <stdio.h> -#include <stdlib.h> -#include <stddef.h> -#include <string.h> - -#include "nsswitch.h" -#include <arpa/nameser.h> - -/* Get implementeation for some internal functions. */ -#include <resolv/resolv-internal.h> -#include <resolv/mapv4v6addr.h> -#include <resolv/mapv4v6hostent.h> - -#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 - -/* We need this time later. */ -typedef union querybuf -{ - HEADER hdr; - u_char buf[MAXPACKET]; -} querybuf; - -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) - -/* Return the expected RDATA length for an address record type (A or - AAAA). */ -static int -rrtype_to_rdata_length (int type) -{ - switch (type) - { - case T_A: - return INADDRSZ; - case T_AAAA: - return IN6ADDRSZ; - default: - return -1; - } -} - -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_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_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_QUERY_A_AND_AAAA, - 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: - 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) - { - *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; - } - - 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; - - 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; - *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); -} - -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; -} - -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 (__glibc_unlikely (qdcount != 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 (__glibc_unlikely (errno == EMSGSIZE)) - goto too_small; - - n = -1; - } - - if (n > 0 && bp[0] == '.') - bp[0] = '\0'; - - if (__glibc_unlikely (n < 0)) - { - *errnop = errno; - *h_errnop = NO_RECOVERY; - return NSS_STATUS_UNAVAIL; - } - if (__glibc_unlikely (name_ok (bp) == 0)) - { - errno = EBADMSG; - *errnop = EBADMSG; - *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 (__glibc_unlikely (errno == 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 (end_of_message - cp < n) - { - /* RDATA extends beyond the end of the packet. */ - ++had_error; - continue; - } - - 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 (__glibc_unlikely (n >= 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 (__glibc_unlikely (n >= 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) - { - /* 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_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 (__glibc_unlikely (n >= MAXHOSTNAMELEN)) - { - ++had_error; - continue; - } - tname = bp; - bp = __mempcpy (bp, tbuf, n); /* Cannot overflow. */ - linebuflen -= n; - continue; - } - - if (type == T_A && qtype == T_AAAA && map) - have_to_map = 1; - else if (__glibc_unlikely (type != qtype)) - { - cp += n; - continue; /* XXX - had_error++ ? */ - } - - switch (type) - { - case T_PTR: - if (__glibc_unlikely (strcasecmp (tname, bp) != 0)) - { - 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 (__glibc_unlikely (errno == EMSGSIZE)) - goto too_small; - - n = -1; - } - - if (__glibc_unlikely (n < 0 || res_hnok (bp) == 0)) - { - ++had_error; - break; - } - if (ttlp != NULL && ttl < *ttlp) - *ttlp = ttl; - /* 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 (__glibc_unlikely (strcasecmp (result->h_name, bp) != 0)) - { - cp += n; - continue; /* XXX - had_error++ ? */ - } - - /* Stop parsing at a record whose length is incorrect. */ - if (n != rrtype_to_rdata_length (type)) - { - ++had_error; - break; - } - - /* Skip records of the wrong type. */ - 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; - /* - * 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); - - 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 (__glibc_unlikely (errno == EMSGSIZE)) - { - too_small: - *errnop = ERANGE; - *h_errnop = NETDB_INTERNAL; - return NSS_STATUS_TRYAGAIN; - } - - n = -1; - } - - if (__glibc_unlikely (n < 0)) - { - *errnop = errno; - *h_errnop = NO_RECOVERY; - return NSS_STATUS_UNAVAIL; - } - if (__glibc_unlikely (res_hnok (buffer) == 0)) - { - errno = EBADMSG; - *errnop = EBADMSG; - *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) - { - *h_errnop = HOST_NOT_FOUND; - 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 (__glibc_unlikely (errno == 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 (end_of_message - cp < n) - { - /* RDATA extends beyond the end of the packet. */ - ++had_error; - continue; - } - - 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; - } - - /* Stop parsing if we encounter a record with incorrect RDATA - length. */ - if (type == T_A || type == T_AAAA) - { - if (n != rrtype_to_rdata_length (type)) - { - ++had_error; - continue; - } - } - else - { - /* Skip unknown records. */ - cp += n; - continue; - } - - assert (type == T_A || type == T_AAAA); - if (*pat == NULL) - { - uintptr_t pad = (-(uintptr_t) buffer - % __alignof__ (struct gaih_addrtuple)); - buffer += pad; - buflen = buflen > pad ? buflen - pad : 0; - - if (__glibc_unlikely (buflen < sizeof (struct gaih_addrtuple))) - 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; - 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. */ - if (canon != NULL) - { - *h_errnop = HOST_NOT_FOUND; - return NSS_STATUS_NOTFOUND; - } - - *h_errnop = NETDB_INTERNAL; - return NSS_STATUS_TRYAGAIN; -} - - -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; - - /* Combining the NSS status of two distinct queries requires some - compromise and attention to symmetry (A or AAAA queries can be - returned in any order). What follows is a breakdown of how this - code is expected to work and why. We discuss only SUCCESS, - TRYAGAIN, NOTFOUND and UNAVAIL, since they are the only returns - that apply (though RETURN and MERGE exist). We make a distinction - between TRYAGAIN (recoverable) and TRYAGAIN' (not-recoverable). - A recoverable TRYAGAIN is almost always due to buffer size issues - and returns ERANGE in errno and the caller is expected to retry - with a larger buffer. - - Lastly, you may be tempted to make significant changes to the - conditions in this code to bring about symmetry between responses. - Please don't change anything without due consideration for - expected application behaviour. Some of the synthesized responses - aren't very well thought out and sometimes appear to imply that - IPv4 responses are always answer 1, and IPv6 responses are always - answer 2, but that's not true (see the implementation of send_dg - and send_vc to see response can arrive in any order, particularly - for UDP). However, we expect it holds roughly enough of the time - that this code works, but certainly needs to be fixed to make this - a more robust implementation. - - ---------------------------------------------- - | Answer 1 Status / | Synthesized | Reason | - | Answer 2 Status | Status | | - |--------------------------------------------| - | SUCCESS/SUCCESS | SUCCESS | [1] | - | SUCCESS/TRYAGAIN | TRYAGAIN | [5] | - | SUCCESS/TRYAGAIN' | SUCCESS | [1] | - | SUCCESS/NOTFOUND | SUCCESS | [1] | - | SUCCESS/UNAVAIL | SUCCESS | [1] | - | TRYAGAIN/SUCCESS | TRYAGAIN | [2] | - | TRYAGAIN/TRYAGAIN | TRYAGAIN | [2] | - | TRYAGAIN/TRYAGAIN' | TRYAGAIN | [2] | - | TRYAGAIN/NOTFOUND | TRYAGAIN | [2] | - | TRYAGAIN/UNAVAIL | TRYAGAIN | [2] | - | TRYAGAIN'/SUCCESS | SUCCESS | [3] | - | TRYAGAIN'/TRYAGAIN | TRYAGAIN | [3] | - | TRYAGAIN'/TRYAGAIN' | TRYAGAIN' | [3] | - | TRYAGAIN'/NOTFOUND | TRYAGAIN' | [3] | - | TRYAGAIN'/UNAVAIL | UNAVAIL | [3] | - | NOTFOUND/SUCCESS | SUCCESS | [3] | - | NOTFOUND/TRYAGAIN | TRYAGAIN | [3] | - | NOTFOUND/TRYAGAIN' | TRYAGAIN' | [3] | - | NOTFOUND/NOTFOUND | NOTFOUND | [3] | - | NOTFOUND/UNAVAIL | UNAVAIL | [3] | - | UNAVAIL/SUCCESS | UNAVAIL | [4] | - | UNAVAIL/TRYAGAIN | UNAVAIL | [4] | - | UNAVAIL/TRYAGAIN' | UNAVAIL | [4] | - | UNAVAIL/NOTFOUND | UNAVAIL | [4] | - | UNAVAIL/UNAVAIL | UNAVAIL | [4] | - ---------------------------------------------- - - [1] If the first response is a success we return success. - This ignores the state of the second answer and in fact - incorrectly sets errno and h_errno to that of the second - answer. However because the response is a success we ignore - *errnop and *h_errnop (though that means you touched errno on - success). We are being conservative here and returning the - likely IPv4 response in the first answer as a success. - - [2] If the first response is a recoverable TRYAGAIN we return - that instead of looking at the second response. The - expectation here is that we have failed to get an IPv4 response - and should retry both queries. - - [3] If the first response was not a SUCCESS and the second - response is not NOTFOUND (had a SUCCESS, need to TRYAGAIN, - or failed entirely e.g. TRYAGAIN' and UNAVAIL) then use the - result from the second response, otherwise the first responses - status is used. Again we have some odd side-effects when the - second response is NOTFOUND because we overwrite *errnop and - *h_errnop that means that a first answer of NOTFOUND might see - its *errnop and *h_errnop values altered. Whether it matters - in practice that a first response NOTFOUND has the wrong - *errnop and *h_errnop is undecided. - - [4] If the first response is UNAVAIL we return that instead of - looking at the second response. The expectation here is that - it will have failed similarly e.g. configuration failure. - - [5] Testing this code is complicated by the fact that truncated - second response buffers might be returned as SUCCESS if the - first answer is a SUCCESS. To fix this we add symmetry to - TRYAGAIN with the second response. If the second response - is a recoverable error we now return TRYAGIN even if the first - response was SUCCESS. */ - - 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); - /* Use the second response status in some cases. */ - if (status != NSS_STATUS_SUCCESS && status2 != NSS_STATUS_NOTFOUND) - status = status2; - /* Do not return a truncated second response (unless it was - unavoidable e.g. unrecoverable TRYAGAIN). */ - if (status == NSS_STATUS_SUCCESS - && (status2 == NSS_STATUS_TRYAGAIN - && *errnop == ERANGE && *h_errnop != NO_RECOVERY)) - status = NSS_STATUS_TRYAGAIN; - } - - return status; -} |