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* All files with FSF copyright notices: Update copyright dates using scripts/update-copyrights. * locale/programs/charmap-kw.h: Regenerated. * locale/programs/locfile-kw.h: Likewise.
708 lines
23 KiB
C
708 lines
23 KiB
C
/* Resolver state initialization and resolv.conf parsing.
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Copyright (C) 1995-2018 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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/*
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* Copyright (c) 1985, 1989, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*
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* Portions Copyright (c) 1993 by Digital Equipment Corporation.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies, and that
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* the name of Digital Equipment Corporation not be used in advertising or
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* publicity pertaining to distribution of the document or software without
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* specific, written prior permission.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
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* WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
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* CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
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* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
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* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
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* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
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* SOFTWARE.
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*/
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/*
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* Portions Copyright (c) 1996-1999 by Internet Software Consortium.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
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* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
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* CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
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* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
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* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
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* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
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* SOFTWARE.
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*/
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#include <ctype.h>
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#include <netdb.h>
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#include <resolv/resolv-internal.h>
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#include <res_hconf.h>
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#include <stdio.h>
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#include <stdio_ext.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <stdint.h>
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#include <arpa/inet.h>
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#include <arpa/nameser.h>
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#include <net/if.h>
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#include <netinet/in.h>
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#include <sys/param.h>
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#include <sys/socket.h>
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#include <sys/time.h>
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#include <sys/types.h>
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#include <inet/net-internal.h>
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#include <errno.h>
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#include <resolv_conf.h>
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static uint32_t net_mask (struct in_addr);
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int
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res_ninit (res_state statp)
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{
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return __res_vinit (statp, 0);
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}
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libc_hidden_def (__res_ninit)
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/* Return true if CH separates the netmask in the "sortlist"
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directive. */
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static inline bool
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is_sort_mask (char ch)
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{
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return ch == '/' || ch == '&';
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}
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/* Array of name server addresses. */
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#define DYNARRAY_STRUCT nameserver_list
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#define DYNARRAY_ELEMENT const struct sockaddr *
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#define DYNARRAY_ELEMENT_FREE(e) free ((struct sockaddr *) *(e))
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#define DYNARRAY_INITIAL_SIZE 3
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#define DYNARRAY_PREFIX nameserver_list_
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#include <malloc/dynarray-skeleton.c>
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/* Array of strings for the search array. The backing store is
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managed separately. */
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#define DYNARRAY_STRUCT search_list
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#define DYNARRAY_ELEMENT const char *
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#define DYNARRAY_INITIAL_SIZE 6
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#define DYNARRAY_PREFIX search_list_
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#include <malloc/dynarray-skeleton.c>
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/* Array of name server addresses. */
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#define DYNARRAY_STRUCT sort_list
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#define DYNARRAY_ELEMENT struct resolv_sortlist_entry
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#define DYNARRAY_INITIAL_SIZE 0
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#define DYNARRAY_PREFIX sort_list_
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#include <malloc/dynarray-skeleton.c>
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/* resolv.conf parser state and results. */
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struct resolv_conf_parser
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{
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char *buffer; /* Temporary buffer for reading lines. */
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struct nameserver_list nameserver_list; /* Nameserver addresses. */
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char *search_list_store; /* Backing storage for search list entries. */
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struct search_list search_list; /* Points into search_list_store. */
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struct sort_list sort_list; /* Address preference sorting list. */
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/* Configuration template. The non-array elements are filled in
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directly. The array elements are updated prior to the call to
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__resolv_conf_attach. */
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struct resolv_conf template;
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};
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/* Return true if *PREINIT contains actual preinitialization. */
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static bool
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has_preinit_values (const struct __res_state *preinit)
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{
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return (preinit->retrans != 0 && preinit->retrans != RES_TIMEOUT)
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|| (preinit->retry != 0 && preinit->retry != RES_DFLRETRY)
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|| (preinit->options != 0
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&& (preinit->options & ~RES_INIT) != RES_DEFAULT);
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}
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static void
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resolv_conf_parser_init (struct resolv_conf_parser *parser,
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const struct __res_state *preinit)
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{
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parser->buffer = NULL;
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parser->search_list_store = NULL;
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nameserver_list_init (&parser->nameserver_list);
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search_list_init (&parser->search_list);
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sort_list_init (&parser->sort_list);
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if (preinit != NULL)
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{
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parser->template.retrans = preinit->retrans;
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parser->template.retry = preinit->retry;
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parser->template.options = preinit->options | RES_INIT;
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}
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else
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{
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parser->template.retrans = RES_TIMEOUT;
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parser->template.retry = RES_DFLRETRY;
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parser->template.options = RES_DEFAULT | RES_INIT;
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}
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parser->template.ndots = 1;
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}
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static void
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resolv_conf_parser_free (struct resolv_conf_parser *parser)
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{
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free (parser->buffer);
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free (parser->search_list_store);
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nameserver_list_free (&parser->nameserver_list);
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search_list_free (&parser->search_list);
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sort_list_free (&parser->sort_list);
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}
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/* Allocate a struct sockaddr_in object on the heap, with the
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specified address and port. */
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static struct sockaddr *
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allocate_address_v4 (struct in_addr a, uint16_t port)
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{
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struct sockaddr_in *sa4 = malloc (sizeof (*sa4));
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if (sa4 == NULL)
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return NULL;
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sa4->sin_family = AF_INET;
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sa4->sin_addr = a;
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sa4->sin_port = htons (port);
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return (struct sockaddr *) sa4;
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}
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/* Try to obtain the domain name from the host name and store it in
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*RESULT. Return false on memory allocation failure. If the domain
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name cannot be determined for any other reason, write NULL to
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*RESULT and return true. */
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static bool
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domain_from_hostname (char **result)
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{
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char buf[256];
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/* gethostbyname may not terminate the buffer. */
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buf[sizeof (buf) - 1] = '\0';
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if (__gethostname (buf, sizeof (buf) - 1) == 0)
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{
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char *dot = strchr (buf, '.');
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if (dot != NULL)
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{
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*result = __strdup (dot + 1);
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if (*result == NULL)
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return false;
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return true;
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}
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}
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*result = NULL;
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return true;
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}
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static void res_setoptions (struct resolv_conf_parser *, const char *options);
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/* Internal helper function for __res_vinit, to aid with resource
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deallocation and error handling. Return true on success, false on
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failure. */
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static bool
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res_vinit_1 (FILE *fp, struct resolv_conf_parser *parser)
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{
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char *cp;
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size_t buffer_size = 0;
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bool haveenv = false;
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/* Allow user to override the local domain definition. */
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if ((cp = getenv ("LOCALDOMAIN")) != NULL)
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{
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/* The code below splits the string in place. */
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cp = __strdup (cp);
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if (cp == NULL)
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return false;
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free (parser->search_list_store);
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parser->search_list_store = cp;
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haveenv = true;
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/* The string will be truncated as needed below. */
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search_list_add (&parser->search_list, cp);
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/* Set search list to be blank-separated strings from rest of
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env value. Permits users of LOCALDOMAIN to still have a
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search list, and anyone to set the one that they want to use
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as an individual (even more important now that the rfc1535
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stuff restricts searches). */
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for (bool in_name = true; *cp != '\0'; cp++)
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{
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if (*cp == '\n')
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{
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*cp = '\0';
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break;
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}
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else if (*cp == ' ' || *cp == '\t')
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{
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*cp = '\0';
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in_name = false;
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}
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else if (!in_name)
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{
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search_list_add (&parser->search_list, cp);
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in_name = true;
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}
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}
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}
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#define MATCH(line, name) \
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(!strncmp ((line), name, sizeof (name) - 1) \
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&& ((line)[sizeof (name) - 1] == ' ' \
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|| (line)[sizeof (name) - 1] == '\t'))
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if (fp != NULL)
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{
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/* No threads use this stream. */
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__fsetlocking (fp, FSETLOCKING_BYCALLER);
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/* Read the config file. */
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while (true)
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{
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{
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ssize_t ret = __getline (&parser->buffer, &buffer_size, fp);
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if (ret <= 0)
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{
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if (_IO_ferror_unlocked (fp))
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return false;
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else
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break;
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}
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}
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/* Skip comments. */
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if (*parser->buffer == ';' || *parser->buffer == '#')
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continue;
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/* Read default domain name. */
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if (MATCH (parser->buffer, "domain"))
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{
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if (haveenv)
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/* LOCALDOMAIN overrides the configuration file. */
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continue;
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cp = parser->buffer + sizeof ("domain") - 1;
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while (*cp == ' ' || *cp == '\t')
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cp++;
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if ((*cp == '\0') || (*cp == '\n'))
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continue;
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cp = __strdup (cp);
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if (cp == NULL)
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return false;
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free (parser->search_list_store);
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parser->search_list_store = cp;
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search_list_clear (&parser->search_list);
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search_list_add (&parser->search_list, cp);
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/* Replace trailing whitespace. */
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if ((cp = strpbrk (cp, " \t\n")) != NULL)
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*cp = '\0';
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continue;
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}
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/* Set search list. */
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if (MATCH (parser->buffer, "search"))
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{
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if (haveenv)
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/* LOCALDOMAIN overrides the configuration file. */
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continue;
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cp = parser->buffer + sizeof ("search") - 1;
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while (*cp == ' ' || *cp == '\t')
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cp++;
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if ((*cp == '\0') || (*cp == '\n'))
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continue;
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{
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char *p = strchr (cp, '\n');
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if (p != NULL)
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*p = '\0';
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}
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cp = __strdup (cp);
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if (cp == NULL)
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return false;
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free (parser->search_list_store);
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parser->search_list_store = cp;
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/* The string is truncated below. */
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search_list_clear (&parser->search_list);
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search_list_add (&parser->search_list, cp);
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/* Set search list to be blank-separated strings on rest
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of line. */
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for (bool in_name = true; *cp != '\0'; cp++)
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{
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if (*cp == ' ' || *cp == '\t')
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{
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*cp = '\0';
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in_name = false;
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}
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else if (!in_name)
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{
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search_list_add (&parser->search_list, cp);
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in_name = true;
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}
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}
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continue;
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}
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/* Read nameservers to query. */
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if (MATCH (parser->buffer, "nameserver"))
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{
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struct in_addr a;
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cp = parser->buffer + sizeof ("nameserver") - 1;
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while (*cp == ' ' || *cp == '\t')
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cp++;
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struct sockaddr *sa;
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if ((*cp != '\0') && (*cp != '\n') && __inet_aton (cp, &a))
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{
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sa = allocate_address_v4 (a, NAMESERVER_PORT);
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if (sa == NULL)
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return false;
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}
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else
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{
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struct in6_addr a6;
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char *el;
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if ((el = strpbrk (cp, " \t\n")) != NULL)
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*el = '\0';
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if ((el = strchr (cp, SCOPE_DELIMITER)) != NULL)
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*el = '\0';
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if ((*cp != '\0') && (__inet_pton (AF_INET6, cp, &a6) > 0))
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{
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struct sockaddr_in6 *sa6;
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sa6 = malloc (sizeof (*sa6));
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if (sa6 == NULL)
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return false;
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sa6->sin6_family = AF_INET6;
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sa6->sin6_port = htons (NAMESERVER_PORT);
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sa6->sin6_flowinfo = 0;
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sa6->sin6_addr = a6;
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sa6->sin6_scope_id = 0;
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if (__glibc_likely (el != NULL))
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/* Ignore errors, for backwards
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compatibility. */
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__inet6_scopeid_pton
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(&a6, el + 1, &sa6->sin6_scope_id);
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sa = (struct sockaddr *) sa6;
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}
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else
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/* IPv6 address parse failure. */
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sa = NULL;
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}
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if (sa != NULL)
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{
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const struct sockaddr **p = nameserver_list_emplace
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(&parser->nameserver_list);
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if (p != NULL)
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*p = sa;
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else
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{
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free (sa);
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return false;
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}
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}
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continue;
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}
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if (MATCH (parser->buffer, "sortlist"))
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{
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struct in_addr a;
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cp = parser->buffer + sizeof ("sortlist") - 1;
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while (true)
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{
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while (*cp == ' ' || *cp == '\t')
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cp++;
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if (*cp == '\0' || *cp == '\n' || *cp == ';')
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break;
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char *net = cp;
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while (*cp && !is_sort_mask (*cp) && *cp != ';'
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&& isascii (*cp) && !isspace (*cp))
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cp++;
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char separator = *cp;
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*cp = 0;
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struct resolv_sortlist_entry e;
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if (__inet_aton (net, &a))
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{
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e.addr = a;
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if (is_sort_mask (separator))
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{
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*cp++ = separator;
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net = cp;
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while (*cp && *cp != ';'
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&& isascii (*cp) && !isspace (*cp))
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cp++;
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separator = *cp;
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*cp = 0;
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if (__inet_aton (net, &a))
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e.mask = a.s_addr;
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else
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e.mask = net_mask (e.addr);
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}
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else
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e.mask = net_mask (e.addr);
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sort_list_add (&parser->sort_list, e);
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}
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*cp = separator;
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}
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continue;
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}
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if (MATCH (parser->buffer, "options"))
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{
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res_setoptions (parser, parser->buffer + sizeof ("options") - 1);
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continue;
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}
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}
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fclose (fp);
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}
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if (__glibc_unlikely (nameserver_list_size (&parser->nameserver_list) == 0))
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{
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const struct sockaddr **p
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= nameserver_list_emplace (&parser->nameserver_list);
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if (p == NULL)
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return false;
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*p = allocate_address_v4 (__inet_makeaddr (IN_LOOPBACKNET, 1),
|
|
NAMESERVER_PORT);
|
|
if (*p == NULL)
|
|
return false;
|
|
}
|
|
|
|
if (search_list_size (&parser->search_list) == 0)
|
|
{
|
|
char *domain;
|
|
if (!domain_from_hostname (&domain))
|
|
return false;
|
|
if (domain != NULL)
|
|
{
|
|
free (parser->search_list_store);
|
|
parser->search_list_store = domain;
|
|
search_list_add (&parser->search_list, domain);
|
|
}
|
|
}
|
|
|
|
if ((cp = getenv ("RES_OPTIONS")) != NULL)
|
|
res_setoptions (parser, cp);
|
|
|
|
if (nameserver_list_has_failed (&parser->nameserver_list)
|
|
|| search_list_has_failed (&parser->search_list)
|
|
|| sort_list_has_failed (&parser->sort_list))
|
|
{
|
|
__set_errno (ENOMEM);
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
struct resolv_conf *
|
|
__resolv_conf_load (struct __res_state *preinit)
|
|
{
|
|
/* Ensure that /etc/hosts.conf has been loaded (once). */
|
|
_res_hconf_init ();
|
|
|
|
FILE *fp = fopen (_PATH_RESCONF, "rce");
|
|
if (fp == NULL)
|
|
switch (errno)
|
|
{
|
|
case EACCES:
|
|
case EISDIR:
|
|
case ELOOP:
|
|
case ENOENT:
|
|
case ENOTDIR:
|
|
case EPERM:
|
|
/* Ignore these errors. They are persistent errors caused
|
|
by file system contents. */
|
|
break;
|
|
default:
|
|
/* Other errors refer to resource allocation problems and
|
|
need to be handled by the application. */
|
|
return NULL;
|
|
}
|
|
|
|
struct resolv_conf_parser parser;
|
|
resolv_conf_parser_init (&parser, preinit);
|
|
|
|
struct resolv_conf *conf = NULL;
|
|
if (res_vinit_1 (fp, &parser))
|
|
{
|
|
parser.template.nameserver_list
|
|
= nameserver_list_begin (&parser.nameserver_list);
|
|
parser.template.nameserver_list_size
|
|
= nameserver_list_size (&parser.nameserver_list);
|
|
parser.template.search_list = search_list_begin (&parser.search_list);
|
|
parser.template.search_list_size
|
|
= search_list_size (&parser.search_list);
|
|
parser.template.sort_list = sort_list_begin (&parser.sort_list);
|
|
parser.template.sort_list_size = sort_list_size (&parser.sort_list);
|
|
conf = __resolv_conf_allocate (&parser.template);
|
|
}
|
|
resolv_conf_parser_free (&parser);
|
|
|
|
return conf;
|
|
}
|
|
|
|
/* Set up default settings. If the /etc/resolv.conf configuration
|
|
file exist, the values there will have precedence. Otherwise, the
|
|
server address is set to INADDR_LOOPBACK and the default domain
|
|
name comes from gethostname. The RES_OPTIONS and LOCALDOMAIN
|
|
environment variables can be used to override some settings.
|
|
Return 0 if completes successfully, -1 on error. */
|
|
int
|
|
__res_vinit (res_state statp, int preinit)
|
|
{
|
|
struct resolv_conf *conf;
|
|
if (preinit && has_preinit_values (statp))
|
|
/* For the preinit case, we cannot use the cached configuration
|
|
because some settings could be different. */
|
|
conf = __resolv_conf_load (statp);
|
|
else
|
|
conf = __resolv_conf_get_current ();
|
|
if (conf == NULL)
|
|
return -1;
|
|
|
|
bool ok = __resolv_conf_attach (statp, conf);
|
|
__resolv_conf_put (conf);
|
|
if (ok)
|
|
{
|
|
if (preinit)
|
|
statp->id = res_randomid ();
|
|
return 0;
|
|
}
|
|
else
|
|
return -1;
|
|
}
|
|
|
|
static void
|
|
res_setoptions (struct resolv_conf_parser *parser, const char *options)
|
|
{
|
|
const char *cp = options;
|
|
|
|
while (*cp)
|
|
{
|
|
/* Skip leading and inner runs of spaces. */
|
|
while (*cp == ' ' || *cp == '\t')
|
|
cp++;
|
|
/* Search for and process individual options. */
|
|
if (!strncmp (cp, "ndots:", sizeof ("ndots:") - 1))
|
|
{
|
|
int i = atoi (cp + sizeof ("ndots:") - 1);
|
|
if (i <= RES_MAXNDOTS)
|
|
parser->template.ndots = i;
|
|
else
|
|
parser->template.ndots = RES_MAXNDOTS;
|
|
}
|
|
else if (!strncmp (cp, "timeout:", sizeof ("timeout:") - 1))
|
|
{
|
|
int i = atoi (cp + sizeof ("timeout:") - 1);
|
|
if (i <= RES_MAXRETRANS)
|
|
parser->template.retrans = i;
|
|
else
|
|
parser->template.retrans = RES_MAXRETRANS;
|
|
}
|
|
else if (!strncmp (cp, "attempts:", sizeof ("attempts:") - 1))
|
|
{
|
|
int i = atoi (cp + sizeof ("attempts:") - 1);
|
|
if (i <= RES_MAXRETRY)
|
|
parser->template.retry = i;
|
|
else
|
|
parser->template.retry = RES_MAXRETRY;
|
|
}
|
|
else
|
|
{
|
|
static const struct
|
|
{
|
|
char str[22];
|
|
uint8_t len;
|
|
uint8_t clear;
|
|
unsigned long int flag;
|
|
} options[] = {
|
|
#define STRnLEN(str) str, sizeof (str) - 1
|
|
{ STRnLEN ("inet6"), 0, DEPRECATED_RES_USE_INET6 },
|
|
{ STRnLEN ("rotate"), 0, RES_ROTATE },
|
|
{ STRnLEN ("edns0"), 0, RES_USE_EDNS0 },
|
|
{ STRnLEN ("single-request-reopen"), 0, RES_SNGLKUPREOP },
|
|
{ STRnLEN ("single-request"), 0, RES_SNGLKUP },
|
|
{ STRnLEN ("no_tld_query"), 0, RES_NOTLDQUERY },
|
|
{ STRnLEN ("no-tld-query"), 0, RES_NOTLDQUERY },
|
|
{ STRnLEN ("no-reload"), 0, RES_NORELOAD },
|
|
{ STRnLEN ("use-vc"), 0, RES_USEVC }
|
|
};
|
|
#define noptions (sizeof (options) / sizeof (options[0]))
|
|
for (int i = 0; i < noptions; ++i)
|
|
if (strncmp (cp, options[i].str, options[i].len) == 0)
|
|
{
|
|
if (options[i].clear)
|
|
parser->template.options &= options[i].flag;
|
|
else
|
|
parser->template.options |= options[i].flag;
|
|
break;
|
|
}
|
|
}
|
|
/* Skip to next run of spaces. */
|
|
while (*cp && *cp != ' ' && *cp != '\t')
|
|
cp++;
|
|
}
|
|
}
|
|
|
|
static uint32_t
|
|
net_mask (struct in_addr in)
|
|
{
|
|
uint32_t i = ntohl (in.s_addr);
|
|
|
|
if (IN_CLASSA (i))
|
|
return htonl (IN_CLASSA_NET);
|
|
else if (IN_CLASSB (i))
|
|
return htonl (IN_CLASSB_NET);
|
|
return htonl (IN_CLASSC_NET);
|
|
}
|