905 lines
20 KiB
C
905 lines
20 KiB
C
/*
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* auth.c - PPP authentication and phase control.
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*
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* Copyright (c) 1993 The Australian National University.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms are permitted
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* provided that the above copyright notice and this paragraph are
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* duplicated in all such forms and that any documentation,
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* advertising materials, and other materials related to such
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* distribution and use acknowledge that the software was developed
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* by the Australian National University. The name of the University
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* may not be used to endorse or promote products derived from this
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* software without specific prior written permission.
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
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* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*
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* Copyright (c) 1989 Carnegie Mellon University.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms are permitted
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* provided that the above copyright notice and this paragraph are
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* duplicated in all such forms and that any documentation,
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* advertising materials, and other materials related to such
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* distribution and use acknowledge that the software was developed
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* by Carnegie Mellon University. The name of the
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* University may not be used to endorse or promote products derived
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* from this software without specific prior written permission.
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
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* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*/
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#ifndef lint
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static char rcsid[] = "$Id: auth.c,v 1.6 1994/05/25 06:25:05 paulus Exp $";
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#endif
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#include <stdio.h>
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#include <stddef.h>
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#include <syslog.h>
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#include <pwd.h>
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#include <string.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <netdb.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include "ppp.h"
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#include "pppd.h"
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#include "fsm.h"
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#include "lcp.h"
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#include "upap.h"
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#include "chap.h"
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#include "ipcp.h"
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#include "pathnames.h"
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#ifdef sparc
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#include <alloca.h>
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#endif /*sparc*/
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/* Used for storing a sequence of words. Usually malloced. */
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struct wordlist {
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struct wordlist *next;
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char word[1];
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};
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/* Bits in scan_authfile return value */
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#define NONWILD_SERVER 1
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#define NONWILD_CLIENT 2
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#define ISWILD(word) (word[0] == '*' && word[1] == 0)
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#define FALSE 0
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#define TRUE 1
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extern char user[];
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extern char passwd[];
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extern char devname[];
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extern char our_name[];
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extern char remote_name[];
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extern char hostname[];
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extern int uselogin;
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extern int usehostname;
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extern int auth_required;
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/* Records which authentication operations haven't completed yet. */
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static int auth_pending[NPPP];
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static int logged_in;
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static struct wordlist *addresses[NPPP];
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/* Bits in auth_pending[] */
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#define UPAP_WITHPEER 1
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#define UPAP_PEER 2
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#define CHAP_WITHPEER 4
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#define CHAP_PEER 8
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/* Prototypes */
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void check_access __ARGS((FILE *, char *));
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static int login __ARGS((char *, char *, char **, int *));
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static void logout __ARGS((void));
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static int null_login __ARGS((int));
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static int get_upap_passwd __ARGS((void));
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static int have_upap_secret __ARGS((void));
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static int have_chap_secret __ARGS((char *, char *));
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static int scan_authfile __ARGS((FILE *, char *, char *, char *,
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struct wordlist **, char *));
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static void free_wordlist __ARGS((struct wordlist *));
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extern char *crypt __ARGS((char *, char *));
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/*
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* An Open on LCP has requested a change from Dead to Establish phase.
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* Do what's necessary to bring the physical layer up.
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*/
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void
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link_required(unit)
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int unit;
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{
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}
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/*
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* LCP has terminated the link; go to the Dead phase and take the
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* physical layer down.
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*/
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void
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link_terminated(unit)
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int unit;
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{
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if (logged_in)
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logout();
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phase = PHASE_DEAD;
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syslog(LOG_NOTICE, "Connection terminated.");
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}
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/*
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* LCP has gone down; it will either die or try to re-establish.
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*/
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void
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link_down(unit)
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int unit;
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{
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phase = PHASE_TERMINATE;
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}
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/*
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* The link is established.
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* Proceed to the Dead, Authenticate or Network phase as appropriate.
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*/
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void
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link_established(unit)
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int unit;
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{
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int auth;
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lcp_options *wo = &lcp_wantoptions[unit];
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lcp_options *go = &lcp_gotoptions[unit];
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lcp_options *ho = &lcp_hisoptions[unit];
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if (auth_required && !(go->neg_chap || go->neg_upap)) {
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/*
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* We wanted the peer to authenticate itself, and it refused:
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* treat it as though it authenticated with PAP using a username
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* of "" and a password of "". If that's not OK, boot it out.
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*/
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if (wo->neg_upap && !null_login(unit)) {
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syslog(LOG_WARNING, "peer refused to authenticate");
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lcp_close(unit);
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phase = PHASE_TERMINATE;
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return;
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}
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}
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phase = PHASE_AUTHENTICATE;
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auth = 0;
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if (go->neg_chap) {
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ChapAuthPeer(unit, our_name, go->chap_mdtype);
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auth |= CHAP_PEER;
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} else if (go->neg_upap) {
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upap_authpeer(unit);
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auth |= UPAP_PEER;
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}
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if (ho->neg_chap) {
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ChapAuthWithPeer(unit, our_name, ho->chap_mdtype);
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auth |= CHAP_WITHPEER;
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} else if (ho->neg_upap) {
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upap_authwithpeer(unit, user, passwd);
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auth |= UPAP_WITHPEER;
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}
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auth_pending[unit] = auth;
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if (!auth) {
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phase = PHASE_NETWORK;
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ipcp_open(unit);
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}
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}
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/*
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* The peer has failed to authenticate himself using `protocol'.
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*/
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void
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auth_peer_fail(unit, protocol)
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int unit, protocol;
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{
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/*
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* Authentication failure: take the link down
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*/
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lcp_close(unit);
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phase = PHASE_TERMINATE;
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}
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/*
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* The peer has been successfully authenticated using `protocol'.
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*/
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void
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auth_peer_success(unit, protocol)
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int unit, protocol;
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{
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int bit;
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switch (protocol) {
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case CHAP:
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bit = CHAP_PEER;
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break;
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case UPAP:
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bit = UPAP_PEER;
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break;
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default:
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syslog(LOG_WARNING, "auth_peer_success: unknown protocol %x",
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protocol);
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return;
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}
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/*
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* If there is no more authentication still to be done,
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* proceed to the network phase.
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*/
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if ((auth_pending[unit] &= ~bit) == 0) {
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phase = PHASE_NETWORK;
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ipcp_open(unit);
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}
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}
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/*
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* We have failed to authenticate ourselves to the peer using `protocol'.
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*/
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void
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auth_withpeer_fail(unit, protocol)
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int unit, protocol;
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{
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/*
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* We've failed to authenticate ourselves to our peer.
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* He'll probably take the link down, and there's not much
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* we can do except wait for that.
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*/
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}
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/*
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* We have successfully authenticated ourselves with the peer using `protocol'.
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*/
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void
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auth_withpeer_success(unit, protocol)
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int unit, protocol;
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{
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int bit;
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switch (protocol) {
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case CHAP:
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bit = CHAP_WITHPEER;
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break;
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case UPAP:
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bit = UPAP_WITHPEER;
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break;
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default:
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syslog(LOG_WARNING, "auth_peer_success: unknown protocol %x",
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protocol);
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bit = 0;
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}
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/*
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* If there is no more authentication still being done,
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* proceed to the network phase.
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*/
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if ((auth_pending[unit] &= ~bit) == 0) {
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phase = PHASE_NETWORK;
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ipcp_open(unit);
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}
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}
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/*
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* check_auth_options - called to check authentication options.
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*/
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void
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check_auth_options()
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{
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lcp_options *wo = &lcp_wantoptions[0];
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lcp_options *ao = &lcp_allowoptions[0];
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/* Default our_name to hostname, and user to our_name */
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if (our_name[0] == 0 || usehostname)
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strcpy(our_name, hostname);
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if (user[0] == 0)
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strcpy(user, our_name);
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/* If authentication is required, ask peer for CHAP or PAP. */
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if (auth_required && !wo->neg_chap && !wo->neg_upap) {
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wo->neg_chap = 1;
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wo->neg_upap = 1;
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}
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/*
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* Check whether we have appropriate secrets to use
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* to authenticate ourselves and/or the peer.
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*/
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if (ao->neg_upap && passwd[0] == 0 && !get_upap_passwd())
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ao->neg_upap = 0;
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if (wo->neg_upap && !uselogin && !have_upap_secret())
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wo->neg_upap = 0;
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if (ao->neg_chap && !have_chap_secret(our_name, remote_name))
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ao->neg_chap = 0;
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if (wo->neg_chap && !have_chap_secret(remote_name, our_name))
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wo->neg_chap = 0;
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if (auth_required && !wo->neg_chap && !wo->neg_upap) {
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fprintf(stderr, "\
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pppd: peer authentication required but no authentication files accessible\n");
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exit(1);
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}
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}
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/*
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* check_passwd - Check the user name and passwd against the PAP secrets
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* file. If requested, also check against the system password database,
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* and login the user if OK.
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*
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* returns:
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* UPAP_AUTHNAK: Authentication failed.
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* UPAP_AUTHACK: Authentication succeeded.
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* In either case, msg points to an appropriate message.
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*/
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int
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check_passwd(unit, auser, userlen, apasswd, passwdlen, msg, msglen)
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int unit;
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char *auser;
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int userlen;
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char *apasswd;
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int passwdlen;
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char **msg;
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int *msglen;
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{
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int ret;
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char *filename;
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FILE *f;
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struct wordlist *addrs;
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char passwd[256], user[256];
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char secret[MAXWORDLEN];
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static int attempts = 0;
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/*
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* Make copies of apasswd and auser, then null-terminate them.
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*/
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BCOPY(apasswd, passwd, passwdlen);
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passwd[passwdlen] = '\0';
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BCOPY(auser, user, userlen);
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user[userlen] = '\0';
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/*
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* Open the file of upap secrets and scan for a suitable secret
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* for authenticating this user.
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*/
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filename = _PATH_UPAPFILE;
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addrs = NULL;
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ret = UPAP_AUTHACK;
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f = fopen(filename, "r");
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if (f == NULL) {
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if (!uselogin) {
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syslog(LOG_ERR, "Can't open upap password file %s: %m", filename);
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ret = UPAP_AUTHNAK;
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}
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} else {
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check_access(f, filename);
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if (scan_authfile(f, user, our_name, secret, &addrs, filename) < 0
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|| (secret[0] != 0 && strcmp(passwd, secret) != 0
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&& strcmp(crypt(passwd, secret), secret) != 0)) {
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syslog(LOG_WARNING, "upap authentication failure for %s", user);
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ret = UPAP_AUTHNAK;
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}
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fclose(f);
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}
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if (uselogin && ret == UPAP_AUTHACK) {
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ret = login(user, passwd, msg, msglen);
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if (ret == UPAP_AUTHNAK) {
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syslog(LOG_WARNING, "upap login failure for %s", user);
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}
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}
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if (ret == UPAP_AUTHNAK) {
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*msg = "Login incorrect";
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*msglen = strlen(*msg);
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/*
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* Frustrate passwd stealer programs.
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* Allow 10 tries, but start backing off after 3 (stolen from login).
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* On 10'th, drop the connection.
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*/
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if (attempts++ >= 10) {
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syslog(LOG_WARNING, "%d LOGIN FAILURES ON %s, %s",
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attempts, devname, user);
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quit();
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}
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if (attempts > 3)
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sleep((u_int) (attempts - 3) * 5);
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if (addrs != NULL)
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free_wordlist(addrs);
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} else {
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attempts = 0; /* Reset count */
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*msg = "Login ok";
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*msglen = strlen(*msg);
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if (addresses[unit] != NULL)
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free_wordlist(addresses[unit]);
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addresses[unit] = addrs;
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}
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return ret;
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}
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/*
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* login - Check the user name and password against the system
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* password database, and login the user if OK.
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*
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* returns:
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* UPAP_AUTHNAK: Login failed.
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* UPAP_AUTHACK: Login succeeded.
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* In either case, msg points to an appropriate message.
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*/
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static int
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login(user, passwd, msg, msglen)
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char *user;
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char *passwd;
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char **msg;
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int *msglen;
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{
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struct passwd *pw;
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char *epasswd;
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char *tty;
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if ((pw = getpwnam(user)) == NULL) {
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return (UPAP_AUTHNAK);
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}
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/*
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* XXX If no passwd, let them login without one.
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*/
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if (pw->pw_passwd == '\0') {
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return (UPAP_AUTHACK);
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}
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epasswd = crypt(passwd, pw->pw_passwd);
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if (strcmp(epasswd, pw->pw_passwd)) {
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return (UPAP_AUTHNAK);
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}
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syslog(LOG_INFO, "user %s logged in", user);
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/*
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* Write a wtmp entry for this user.
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*/
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tty = strrchr(devname, '/');
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if (tty == NULL)
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tty = devname;
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else
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tty++;
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logwtmp(tty, user, ""); /* Add wtmp login entry */
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logged_in = TRUE;
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return (UPAP_AUTHACK);
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}
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/*
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* logout - Logout the user.
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*/
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static void
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logout()
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{
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char *tty;
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tty = strrchr(devname, '/');
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if (tty == NULL)
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tty = devname;
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else
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tty++;
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logwtmp(tty, "", ""); /* Wipe out wtmp logout entry */
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logged_in = FALSE;
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}
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|
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/*
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* null_login - Check if a username of "" and a password of "" are
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* acceptable, and iff so, set the list of acceptable IP addresses
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* and return 1.
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*/
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static int
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null_login(unit)
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int unit;
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{
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char *filename;
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FILE *f;
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int i, ret;
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struct wordlist *addrs;
|
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char secret[MAXWORDLEN];
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/*
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* Open the file of upap secrets and scan for a suitable secret.
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|
* We don't accept a wildcard client.
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*/
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filename = _PATH_UPAPFILE;
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addrs = NULL;
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f = fopen(filename, "r");
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if (f == NULL)
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return 0;
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check_access(f, filename);
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i = scan_authfile(f, "", our_name, secret, &addrs, filename);
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ret = i >= 0 && (i & NONWILD_CLIENT) != 0 && secret[0] == 0;
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if (ret) {
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if (addresses[unit] != NULL)
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free_wordlist(addresses[unit]);
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addresses[unit] = addrs;
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}
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fclose(f);
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return ret;
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}
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|
|
|
|
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/*
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|
* get_upap_passwd - get a password for authenticating ourselves with
|
|
* our peer using PAP. Returns 1 on success, 0 if no suitable password
|
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* could be found.
|
|
*/
|
|
static int
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get_upap_passwd()
|
|
{
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char *filename;
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FILE *f;
|
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struct wordlist *addrs;
|
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char secret[MAXWORDLEN];
|
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|
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filename = _PATH_UPAPFILE;
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addrs = NULL;
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f = fopen(filename, "r");
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if (f == NULL)
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return 0;
|
|
check_access(f, filename);
|
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if (scan_authfile(f, user, remote_name, secret, NULL, filename) < 0)
|
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return 0;
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strncpy(passwd, secret, MAXSECRETLEN);
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|
passwd[MAXSECRETLEN-1] = 0;
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return 1;
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|
}
|
|
|
|
|
|
/*
|
|
* have_upap_secret - check whether we have a PAP file with any
|
|
* secrets that we could possibly use for authenticating the peer.
|
|
*/
|
|
static int
|
|
have_upap_secret()
|
|
{
|
|
FILE *f;
|
|
int ret;
|
|
char *filename;
|
|
|
|
filename = _PATH_UPAPFILE;
|
|
f = fopen(filename, "r");
|
|
if (f == NULL)
|
|
return 0;
|
|
|
|
ret = scan_authfile(f, NULL, our_name, NULL, NULL, filename);
|
|
fclose(f);
|
|
if (ret < 0)
|
|
return 0;
|
|
|
|
return 1;
|
|
}
|
|
|
|
|
|
/*
|
|
* have_chap_secret - check whether we have a CHAP file with a
|
|
* secret that we could possibly use for authenticating `client'
|
|
* on `server'. Either can be the null string, meaning we don't
|
|
* know the identity yet.
|
|
*/
|
|
static int
|
|
have_chap_secret(client, server)
|
|
char *client;
|
|
char *server;
|
|
{
|
|
FILE *f;
|
|
int ret;
|
|
char *filename;
|
|
|
|
filename = _PATH_CHAPFILE;
|
|
f = fopen(filename, "r");
|
|
if (f == NULL)
|
|
return 0;
|
|
|
|
if (client[0] == 0)
|
|
client = NULL;
|
|
else if (server[0] == 0)
|
|
server = NULL;
|
|
|
|
ret = scan_authfile(f, client, server, NULL, NULL, filename);
|
|
fclose(f);
|
|
if (ret < 0)
|
|
return 0;
|
|
|
|
return 1;
|
|
}
|
|
|
|
|
|
/*
|
|
* get_secret - open the CHAP secret file and return the secret
|
|
* for authenticating the given client on the given server.
|
|
* (We could be either client or server).
|
|
*/
|
|
int
|
|
get_secret(unit, client, server, secret, secret_len, save_addrs)
|
|
int unit;
|
|
char *client;
|
|
char *server;
|
|
char *secret;
|
|
int *secret_len;
|
|
int save_addrs;
|
|
{
|
|
FILE *f;
|
|
int ret, len;
|
|
char *filename;
|
|
struct wordlist *addrs;
|
|
char secbuf[MAXWORDLEN];
|
|
|
|
filename = _PATH_CHAPFILE;
|
|
addrs = NULL;
|
|
secbuf[0] = 0;
|
|
|
|
f = fopen(filename, "r");
|
|
if (f == NULL) {
|
|
syslog(LOG_ERR, "Can't open chap secret file %s: %m", filename);
|
|
return 0;
|
|
}
|
|
check_access(f, filename);
|
|
|
|
ret = scan_authfile(f, client, server, secbuf, &addrs, filename);
|
|
fclose(f);
|
|
if (ret < 0)
|
|
return 0;
|
|
|
|
if (save_addrs) {
|
|
if (addresses[unit] != NULL)
|
|
free_wordlist(addresses[unit]);
|
|
addresses[unit] = addrs;
|
|
}
|
|
|
|
len = strlen(secbuf);
|
|
if (len > MAXSECRETLEN) {
|
|
syslog(LOG_ERR, "Secret for %s on %s is too long", client, server);
|
|
len = MAXSECRETLEN;
|
|
}
|
|
BCOPY(secbuf, secret, len);
|
|
*secret_len = len;
|
|
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* auth_ip_addr - check whether the peer is authorized to use
|
|
* a given IP address. Returns 1 if authorized, 0 otherwise.
|
|
*/
|
|
int
|
|
auth_ip_addr(unit, addr)
|
|
int unit;
|
|
u_long addr;
|
|
{
|
|
u_long a;
|
|
struct hostent *hp;
|
|
struct wordlist *addrs;
|
|
|
|
/* don't allow loopback or multicast address */
|
|
if (bad_ip_adrs(addr))
|
|
return 0;
|
|
|
|
if ((addrs = addresses[unit]) == NULL)
|
|
return 1; /* no restriction */
|
|
|
|
for (; addrs != NULL; addrs = addrs->next) {
|
|
/* "-" means no addresses authorized */
|
|
if (strcmp(addrs->word, "-") == 0)
|
|
break;
|
|
if ((a = inet_addr(addrs->word)) == -1) {
|
|
if ((hp = gethostbyname(addrs->word)) == NULL) {
|
|
syslog(LOG_WARNING, "unknown host %s in auth. address list",
|
|
addrs->word);
|
|
continue;
|
|
} else
|
|
a = *(u_long *)hp->h_addr;
|
|
}
|
|
if (addr == a)
|
|
return 1;
|
|
}
|
|
return 0; /* not in list => can't have it */
|
|
}
|
|
|
|
/*
|
|
* bad_ip_adrs - return 1 if the IP address is one we don't want
|
|
* to use, such as an address in the loopback net or a multicast address.
|
|
* addr is in network byte order.
|
|
*/
|
|
int
|
|
bad_ip_adrs(addr)
|
|
u_long addr;
|
|
{
|
|
addr = ntohl(addr);
|
|
return (addr >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET
|
|
|| IN_MULTICAST(addr) || IN_BADCLASS(addr);
|
|
}
|
|
|
|
/*
|
|
* check_access - complain if a secret file has too-liberal permissions.
|
|
*/
|
|
void
|
|
check_access(f, filename)
|
|
FILE *f;
|
|
char *filename;
|
|
{
|
|
struct stat sbuf;
|
|
|
|
if (fstat(fileno(f), &sbuf) < 0) {
|
|
syslog(LOG_WARNING, "cannot stat secret file %s: %m", filename);
|
|
} else if ((sbuf.st_mode & (S_IRWXG | S_IRWXO)) != 0) {
|
|
syslog(LOG_WARNING, "Warning - secret file %s has world and/or group access", filename);
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
* scan_authfile - Scan an authorization file for a secret suitable
|
|
* for authenticating `client' on `server'. The return value is -1
|
|
* if no secret is found, otherwise >= 0. The return value has
|
|
* NONWILD_CLIENT set if the secret didn't have "*" for the client, and
|
|
* NONWILD_SERVER set if the secret didn't have "*" for the server.
|
|
* Any following words on the line (i.e. address authorization
|
|
* info) are placed in a wordlist and returned in *addrs.
|
|
*/
|
|
static int
|
|
scan_authfile(f, client, server, secret, addrs, filename)
|
|
FILE *f;
|
|
char *client;
|
|
char *server;
|
|
char *secret;
|
|
struct wordlist **addrs;
|
|
char *filename;
|
|
{
|
|
int newline, xxx;
|
|
int got_flag, best_flag;
|
|
FILE *sf;
|
|
struct wordlist *ap, *addr_list, *addr_last;
|
|
char word[MAXWORDLEN];
|
|
char atfile[MAXWORDLEN];
|
|
|
|
if (addrs != NULL)
|
|
*addrs = NULL;
|
|
addr_list = NULL;
|
|
if (!getword(f, word, &newline, filename))
|
|
return -1; /* file is empty??? */
|
|
newline = 1;
|
|
best_flag = -1;
|
|
for (;;) {
|
|
/*
|
|
* Skip until we find a word at the start of a line.
|
|
*/
|
|
while (!newline && getword(f, word, &newline, filename))
|
|
;
|
|
if (!newline)
|
|
break; /* got to end of file */
|
|
|
|
/*
|
|
* Got a client - check if it's a match or a wildcard.
|
|
*/
|
|
got_flag = 0;
|
|
if (client != NULL && strcmp(word, client) != 0 && !ISWILD(word)) {
|
|
newline = 0;
|
|
continue;
|
|
}
|
|
if (!ISWILD(word))
|
|
got_flag = NONWILD_CLIENT;
|
|
|
|
/*
|
|
* Now get a server and check if it matches.
|
|
*/
|
|
if (!getword(f, word, &newline, filename))
|
|
break;
|
|
if (newline)
|
|
continue;
|
|
if (server != NULL && strcmp(word, server) != 0 && !ISWILD(word))
|
|
continue;
|
|
if (!ISWILD(word))
|
|
got_flag |= NONWILD_SERVER;
|
|
|
|
/*
|
|
* Got some sort of a match - see if it's better than what
|
|
* we have already.
|
|
*/
|
|
if (got_flag <= best_flag)
|
|
continue;
|
|
|
|
/*
|
|
* Get the secret.
|
|
*/
|
|
if (!getword(f, word, &newline, filename))
|
|
break;
|
|
if (newline)
|
|
continue;
|
|
|
|
/*
|
|
* Special syntax: @filename means read secret from file.
|
|
*/
|
|
if (word[0] == '@') {
|
|
strcpy(atfile, word+1);
|
|
if ((sf = fopen(atfile, "r")) == NULL) {
|
|
syslog(LOG_WARNING, "can't open indirect secret file %s",
|
|
atfile);
|
|
continue;
|
|
}
|
|
check_access(sf, atfile);
|
|
if (!getword(sf, word, &xxx, atfile)) {
|
|
syslog(LOG_WARNING, "no secret in indirect secret file %s",
|
|
atfile);
|
|
fclose(sf);
|
|
continue;
|
|
}
|
|
fclose(sf);
|
|
}
|
|
if (secret != NULL)
|
|
strcpy(secret, word);
|
|
|
|
best_flag = got_flag;
|
|
|
|
/*
|
|
* Now read address authorization info and make a wordlist.
|
|
*/
|
|
if (addr_list)
|
|
free_wordlist(addr_list);
|
|
addr_list = addr_last = NULL;
|
|
for (;;) {
|
|
if (!getword(f, word, &newline, filename) || newline)
|
|
break;
|
|
ap = (struct wordlist *) malloc(sizeof(struct wordlist)
|
|
+ strlen(word));
|
|
if (ap == NULL)
|
|
novm("authorized addresses");
|
|
ap->next = NULL;
|
|
strcpy(ap->word, word);
|
|
if (addr_list == NULL)
|
|
addr_list = ap;
|
|
else
|
|
addr_last->next = ap;
|
|
addr_last = ap;
|
|
}
|
|
if (!newline)
|
|
break;
|
|
}
|
|
|
|
if (addrs != NULL)
|
|
*addrs = addr_list;
|
|
else if (addr_list != NULL)
|
|
free_wordlist(addr_list);
|
|
|
|
return best_flag;
|
|
}
|
|
|
|
/*
|
|
* free_wordlist - release memory allocated for a wordlist.
|
|
*/
|
|
static void
|
|
free_wordlist(wp)
|
|
struct wordlist *wp;
|
|
{
|
|
struct wordlist *next;
|
|
|
|
while (wp != NULL) {
|
|
next = wp->next;
|
|
free(wp);
|
|
wp = next;
|
|
}
|
|
}
|