dmake: do not set MAKEFLAGS=k

[unleashed/tickless.git] / usr / src / cmd / cmd-inet / usr.bin / pppd / auth.c

/*
 * auth.c - PPP authentication and phase control.
 *
 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 1993 The Australian National University.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the Australian National University.  The name of the University
 * may not be used to endorse or promote products derived from this
 * software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 * Copyright (c) 1989 Carnegie Mellon University.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by Carnegie Mellon University.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#define RCSID   "$Id: auth.c,v 1.65 2000/04/15 01:27:10 masputra Exp $"

/* Pull in crypt() definition. */
#define __EXTENSIONS__

#include <stdio.h>
#include <stddef.h>
#include <stdlib.h>
#include <unistd.h>
#include <pwd.h>
#include <grp.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <utmp.h>
#include <fcntl.h>
#if defined(_PATH_LASTLOG) && (defined(_linux_) || defined(__linux__))
#include <lastlog.h>
#endif

#if defined(_linux_) || defined(__linux__)
#include <crypt.h>
#endif

#include <netdb.h>
#include <netinet/in.h>
#include <arpa/inet.h>

/* Backward compatibility with old Makefiles */
#if defined(USE_PAM) && !defined(ALLOW_PAM)
#define ALLOW_PAM
#endif

#ifdef ALLOW_PAM
#include <security/pam_appl.h>
#endif

#ifdef HAS_SHADOW
#include <shadow.h>
#ifndef PW_PPP
#define PW_PPP PW_LOGIN
#endif
#endif

#include "pppd.h"
#include "fsm.h"
#include "lcp.h"
#include "ipcp.h"
#include "upap.h"
#include "chap.h"
#ifdef CBCP_SUPPORT
#include "cbcp.h"
#endif
#include "pathnames.h"

static const char rcsid[] = RCSID;

/* Bits in scan_authfile return value */
#define NONWILD_SERVER  1
#define NONWILD_CLIENT  2

#define ISWILD(word)    (word[0] == '*' && word[1] == '\0')

/* The name by which the peer authenticated itself to us. */
char peer_authname[MAXNAMELEN];

/* Records which authentication operations haven't completed yet. */
static int auth_pending[NUM_PPP];

/* Set if we have successfully called plogin() */
static int logged_in;

/* List of addresses which the peer may use. */
static struct permitted_ip *addresses[NUM_PPP];

/* Wordlist giving addresses which the peer may use
   without authenticating itself. */
static struct wordlist *noauth_addrs;

/* Extra options to apply, from the secrets file entry for the peer. */
static struct wordlist *extra_options;

/* Source of those extra options. */
static const char *extra_opt_filename;
static int extra_opt_line;

/* Number of network protocols which we have opened. */
static int num_np_open;

/* Number of network protocols which have come up. */
static int num_np_up;

/* Set if we got the contents of passwd[] from the pap-secrets file. */
static int passwd_from_file;

/* Set if we require authentication only because we have a default route. */
static bool default_auth;

/* Hook to enable a plugin to control the idle time limit */
int (*idle_time_hook) __P((struct ppp_idle *)) = NULL;

/* Hook for a plugin to say whether we can possibly authenticate any peer */
int (*pap_check_hook) __P((void)) = NULL;

/* Hook for a plugin to check the PAP user and password */
int (*pap_auth_hook) __P((char *user, char *passwd, char **msgp,
                          struct wordlist **paddrs,
                          struct wordlist **popts)) = NULL;

/* Hook for a plugin to know about the PAP user logout */
void (*pap_logout_hook) __P((void)) = NULL;

/* Hook for a plugin to get the PAP password for authenticating us */
int (*pap_passwd_hook) __P((char *user, char *passwd)) = NULL;

/*
 * This is used to ensure that we don't start an auth-up/down
 * script while one is already running.
 */
enum script_state {
    s_down,
    s_up
};

static enum script_state auth_state = s_down;
static enum script_state auth_script_state = s_down;
static pid_t auth_script_pid = 0;

/*
 * This is set by scan_authfile if a client matches, but server doesn't
 * (possible configuration error).
 */
static char scan_server_match_failed[MAXWORDLEN];

/*
 * Option variables.
 */
bool uselogin = 0;              /* Use /etc/passwd for checking PAP */
bool cryptpap = 0;              /* Passwords in pap-secrets are encrypted */
bool refuse_pap = 0;            /* Don't wanna auth. ourselves with PAP */
bool refuse_chap = 0;           /* Don't wanna auth. ourselves with CHAP */
bool usehostname = 0;           /* Use hostname for our_name */
bool auth_required = 0;         /* Always require authentication from peer */
bool allow_any_ip = 0;          /* Allow peer to use any IP address */
bool explicit_remote = 0;       /* User specified explicit remote name */
char remote_name[MAXNAMELEN];   /* Peer's name for authentication */

#ifdef CHAPMS
bool refuse_mschap = 0;         /* Don't wanna auth. ourself with MS-CHAPv1 */
#else
bool refuse_mschap = 1;         /* Never auth. ourself with MS-CHAPv1 */
#endif
#ifdef CHAPMSV2
bool refuse_mschapv2 = 0;       /* Don't wanna auth. ourself with MS-CHAPv2 */
#else
bool refuse_mschapv2 = 1;       /* Never auth. ourself with MS-CHAPv2 */
#endif

#ifdef USE_PAM
bool use_pam = 1;               /* Enable use of PAM by default */
#else
bool use_pam = 0;               /* Disable use of PAM by default */
#endif

/* Bits in auth_pending[] */
#define PAP_WITHPEER    1
#define PAP_PEER        2
#define CHAP_WITHPEER   4
#define CHAP_PEER       8

/* Prototypes for procedures local to this file. */

static void network_phase __P((int));
static void check_idle __P((void *));
static void connect_time_expired __P((void *));
static int  plogin __P((char *, char *, char **));
static void plogout __P((void));
static int  null_login __P((int));
static int  get_pap_passwd __P((char *));
static int  have_pap_secret __P((int *));
static int  have_chap_secret __P((char *, char *, int, int *));
static int  ip_addr_check __P((u_int32_t, struct permitted_ip *));
static int  scan_authfile __P((FILE *, char *, char *, char *,
                               struct wordlist **, struct wordlist **,
                               char *));
static void free_wordlist __P((struct wordlist *));
static void auth_script __P((char *));
static void auth_script_done __P((void *, int));
static void set_allowed_addrs __P((int, struct wordlist *, struct wordlist *));
static int  some_ip_ok __P((struct wordlist *));
static int  setupapfile __P((char **, option_t *));
static int  privgroup __P((char **, option_t *));
static int  set_noauth_addr __P((char **, option_t *));
static void check_access __P((FILE *, char *));

/*
 * Authentication-related options.
 */
option_t auth_options[] = {
    { "require-pap", o_bool, &lcp_wantoptions[0].neg_upap,
      "Require PAP authentication from peer", 1, &auth_required },
    { "+pap", o_bool, &lcp_wantoptions[0].neg_upap,
      "Require PAP authentication from peer", 1, &auth_required },
    { "refuse-pap", o_bool, &refuse_pap,
      "Don't agree to auth to peer with PAP", 1 },
    { "-pap", o_bool, &refuse_pap,
      "Don't allow PAP authentication with peer", 1 },
    { "require-chap", o_bool, &lcp_wantoptions[0].neg_chap,
      "Require CHAP authentication from peer", 1, &auth_required },
    { "+chap", o_bool, &lcp_wantoptions[0].neg_chap,
      "Require CHAP authentication from peer", 1, &auth_required },
    { "refuse-chap", o_bool, &refuse_chap,
      "Don't agree to auth to peer with CHAP", 1 },
    { "-chap", o_bool, &refuse_chap,
      "Don't allow CHAP authentication with peer", 1 },
    { "name", o_string, our_name,
      "Set local name for authentication",
      OPT_PRIV|OPT_STATIC, NULL, MAXNAMELEN },
    { "user", o_string, user,
      "Set name for auth with peer", OPT_STATIC, NULL, MAXNAMELEN },
    { "usehostname", o_bool, &usehostname,
      "Must use hostname for authentication", 1 },
    { "remotename", o_string, remote_name,
      "Set remote name for authentication", OPT_STATIC,
      &explicit_remote, MAXNAMELEN },
    { "auth", o_bool, &auth_required,
      "Require authentication from peer", 1 },
    { "noauth", o_bool, &auth_required,
      "Don't require peer to authenticate", OPT_PRIV, &allow_any_ip },
    {  "login", o_bool, &uselogin,
      "Use system password database for PAP", 1 },
    { "papcrypt", o_bool, &cryptpap,
      "PAP passwords are encrypted", 1 },
    { "+ua", o_special, (void *)setupapfile,
      "Get PAP user and password from file" },
    { "password", o_string, passwd,
      "Password for authenticating us to the peer", OPT_STATIC,
      NULL, MAXSECRETLEN },
    { "privgroup", o_special, (void *)privgroup,
      "Allow group members to use privileged options", OPT_PRIV },
    { "allow-ip", o_special, (void *)set_noauth_addr,
      "Set peer IP address(es) usable without authentication",
      OPT_PRIV },
#ifdef CHAPMS
    { "require-mschap", o_bool, &lcp_wantoptions[0].neg_mschap,
      "Require MS-CHAPv1 authentication from peer", 1, &auth_required },
    { "refuse-mschap", o_bool, &refuse_mschap,
      "Don't agree to authenticate to peer with MS-CHAPv1", 1 },
#endif
#ifdef CHAPMSV2
    { "require-mschapv2", o_bool, &lcp_wantoptions[0].neg_mschapv2,
      "Require MS-CHAPv2 authentication from peer", 1, &auth_required },
    { "refuse-mschapv2", o_bool, &refuse_mschapv2,
      "Don't agree to authenticate to peer with MS-CHAPv2", 1 },
#endif
#ifdef ALLOW_PAM
    { "pam", o_bool, &use_pam,
      "Enable use of Pluggable Authentication Modules", OPT_PRIV|1 },
    { "nopam", o_bool, &use_pam,
      "Disable use of Pluggable Authentication Modules", OPT_PRIV|0 },
#endif
    { NULL }
};

/*
 * setupapfile - specifies UPAP info for authenticating with peer.
 */
/*ARGSUSED*/
static int
setupapfile(argv, opt)
    char **argv;
    option_t *opt;
{
    FILE * ufile;
    int l;

    lcp_allowoptions[0].neg_upap = 1;

    /* open user info file */
    (void) seteuid(getuid());
    ufile = fopen(*argv, "r");
    (void) seteuid(0);
    if (ufile == NULL) {
        option_error("unable to open user login data file %s", *argv);
        return 0;
    }
    check_access(ufile, *argv);

    /* get username */
    if (fgets(user, MAXNAMELEN - 1, ufile) == NULL
        || fgets(passwd, MAXSECRETLEN - 1, ufile) == NULL){
        option_error("unable to read user login data file %s", *argv);
        return 0;
    }
    (void) fclose(ufile);

    /* get rid of newlines */
    l = strlen(user);
    if (l > 0 && user[l-1] == '\n')
        user[l-1] = '\0';
    l = strlen(passwd);
    if (l > 0 && passwd[l-1] == '\n')
        passwd[l-1] = '\0';

    return (1);
}


/*
 * privgroup - allow members of the group to have privileged access.
 */
/*ARGSUSED*/
static int
privgroup(argv, opt)
    char **argv;
    option_t *opt;
{
    struct group *g;
    int i;

    g = getgrnam(*argv);
    if (g == NULL) {
        option_error("group %s is unknown", *argv);
        return 0;
    }
    for (i = 0; i < ngroups; ++i) {
        if (groups[i] == g->gr_gid) {
            privileged = 1;
            break;
        }
    }
    return 1;
}


/*
 * set_noauth_addr - set address(es) that can be used without authentication.
 * Equivalent to specifying an entry like `"" * "" addr' in pap-secrets.
 */
/*ARGSUSED*/
static int
set_noauth_addr(argv, opt)
    char **argv;
    option_t *opt;
{
    char *addr = *argv;
    int l = strlen(addr);
    struct wordlist *wp;

    wp = (struct wordlist *) malloc(sizeof(struct wordlist) + l + 1);
    if (wp == NULL)
        novm("allow-ip argument");
    wp->word = (char *) (wp + 1);
    wp->next = noauth_addrs;
    (void) strcpy(wp->word, addr);
    noauth_addrs = wp;
    return 1;
}

/*
 * An Open on LCP has requested a change from Dead to Establish phase.
 * Do what's necessary to bring the physical layer up.
 */
/*ARGSUSED*/
void
link_required(unit)
    int unit;
{
}

/*
 * LCP has terminated the link; go to the Dead phase and take the
 * physical layer down.
 */
/*ARGSUSED*/
void
link_terminated(unit)
    int unit;
{
    const char *pn1, *pn2;

    if (phase == PHASE_DEAD)
        return;
    if (pap_logout_hook != NULL) {
        (*pap_logout_hook)();
    } else {
        if (logged_in)
            plogout();
    }
    new_phase(PHASE_DEAD);
    if (peer_nak_auth) {
        if ((pn1 = protocol_name(nak_auth_orig)) == NULL)
            pn1 = "?";
        if ((pn2 = protocol_name(nak_auth_proto)) == NULL)
            pn2 = "?";
        warn("Peer sent Configure-Nak for 0x%x (%s) to suggest 0x%x (%s)",
            nak_auth_orig, pn1, nak_auth_proto, pn2);
    }
    if (unsolicited_nak_auth) {
        if ((pn1 = protocol_name(unsolicit_auth_proto)) == NULL)
            pn1 = "?";
        warn("Peer unexpectedly asked us to authenticate with 0x%x (%s)",
            unsolicit_auth_proto, pn1);
    }
    if (peer_reject_auth) {
        if ((pn1 = protocol_name(reject_auth_proto)) == NULL)
            pn1 = "?";
        warn("Peer rejected our demand for 0x%x (%s)",
            reject_auth_proto, pn1);
    }
    if (naked_peers_auth) {
        if ((pn1 = protocol_name(naked_auth_orig)) == NULL)
            pn1 = "?";
        if ((pn2 = protocol_name(naked_auth_proto)) == NULL)
            pn2 = "?";
        warn("We set Configure-Nak for 0x%x (%s) to suggest 0x%x (%s)",
            naked_auth_orig, pn1, naked_auth_proto, pn2);
    }
    if (rejected_peers_auth) {
        if ((pn1 = protocol_name(rejected_auth_proto)) == NULL)
            pn1 = "?";
        warn("We rejected the peer's demand for 0x%x (%s)",
            rejected_auth_proto, pn1);
    }

    peer_nak_auth = unsolicited_nak_auth = peer_reject_auth =
        rejected_peers_auth = naked_peers_auth = 0;
    nak_auth_proto = nak_auth_orig = unsolicit_auth_proto = reject_auth_proto =
        rejected_auth_proto = naked_auth_orig = naked_auth_proto = 0;
    notice("Connection terminated.");
}

/*
 * LCP has gone down; it will either die or try to re-establish.
 */
void
link_down(unit)
    int unit;
{
    int i;
    struct protent *protp;

    auth_state = s_down;
    if (auth_script_state == s_up && auth_script_pid == 0) {
        update_link_stats(unit);
        auth_script_state = s_down;
        auth_script(_PATH_AUTHDOWN);
    }
    for (i = 0; (protp = protocols[i]) != NULL; ++i) {
        if (!protp->enabled_flag)
            continue;
        if (protp->protocol != PPP_LCP && protp->lowerdown != NULL)
            (*protp->lowerdown)(unit);
        if (protp->protocol < 0xC000 && protp->close != NULL)
            (*protp->close)(unit, "LCP down");
    }
    num_np_open = 0;
    num_np_up = 0;
    if (phase != PHASE_DEAD)
        new_phase(PHASE_TERMINATE);
}

/*
 * The link is established.
 * Proceed to the Dead, Authenticate or Network phase as appropriate.
 */
void
link_established(unit)
    int unit;
{
    int auth;
    lcp_options *wo = &lcp_wantoptions[unit];
    lcp_options *go = &lcp_gotoptions[unit];
    lcp_options *ho = &lcp_hisoptions[unit];
    int i;
    struct protent *protp;

    /*
     * Tell higher-level protocols that LCP is up.
     */
    for (i = 0; (protp = protocols[i]) != NULL; ++i)
        if (protp->protocol != PPP_LCP && protp->enabled_flag
            && protp->lowerup != NULL)
            (*protp->lowerup)(unit);

    if (auth_required && !(go->neg_chap || go->neg_mschap ||
        go->neg_mschapv2 || go->neg_upap)) {
        /*
         * We wanted the peer to authenticate itself, and it refused:
         * if we have some address(es) it can use without auth, fine,
         * otherwise treat it as though it authenticated with PAP using
         * a username * of "" and a password of "".  If that's not OK,
         * boot it out.
         */
        if (noauth_addrs != NULL) {
            set_allowed_addrs(unit, noauth_addrs, NULL);
        } else if (!wo->neg_upap || !null_login(unit)) {
            warn("peer refused to authenticate: terminating link");
            lcp_close(unit, "peer refused to authenticate");
            status = EXIT_PEER_AUTH_FAILED;
            return;
        }
    }

    new_phase(PHASE_AUTHENTICATE);
    auth = 0;
    if (go->neg_chap || go->neg_mschap || go->neg_mschapv2) {
        if (go->neg_chap) {
            if (debug)
                dbglog("Authenticating peer with standard CHAP");
            go->chap_mdtype = CHAP_DIGEST_MD5;
        } else if (go->neg_mschap) {
            if (debug)
                dbglog("Authenticating peer with MS-CHAPv1");
            go->chap_mdtype = CHAP_MICROSOFT;
        } else {
            if (debug)
                dbglog("Authenticating peer with MS-CHAPv2");
            go->chap_mdtype = CHAP_MICROSOFT_V2;
        }
        ChapAuthPeer(unit, our_name, go->chap_mdtype);
        auth |= CHAP_PEER;
    } else if (go->neg_upap) {
        if (debug)
            dbglog("Authenticating peer with PAP");
        upap_authpeer(unit);
        auth |= PAP_PEER;
    }
    if (ho->neg_chap || ho->neg_mschap || ho->neg_mschapv2) {
        switch (ho->chap_mdtype) {
        case CHAP_DIGEST_MD5:
            if (debug)
                dbglog("Authenticating to peer with standard CHAP");
            break;
        case CHAP_MICROSOFT:
            if (debug)
                dbglog("Authenticating to peer with MS-CHAPv1");
            break;
        case CHAP_MICROSOFT_V2:
            if (debug)
                dbglog("Authenticating to peer with MS-CHAPv2");
            break;
        default:
            if (debug)
                dbglog("Authenticating to peer with CHAP 0x%x", ho->chap_mdtype);
            break;
        }
        ChapAuthWithPeer(unit, user, ho->chap_mdtype);
        auth |= CHAP_WITHPEER;
    } else if (ho->neg_upap) {
        if (passwd[0] == '\0') {
            passwd_from_file = 1;
            if (!get_pap_passwd(passwd))
                error("No secret found for PAP login");
        }
        if (debug)
            dbglog("Authenticating to peer with PAP");
        upap_authwithpeer(unit, user, passwd);
        auth |= PAP_WITHPEER;
    }
    auth_pending[unit] = auth;

    if (!auth)
        network_phase(unit);
}

/*
 * Proceed to the network phase.
 */
static void
network_phase(unit)
    int unit;
{
    lcp_options *go = &lcp_gotoptions[unit];

    /*
     * If the peer had to authenticate, run the auth-up script now.
     */
    if (go->neg_chap || go->neg_mschap || go->neg_mschapv2 || go->neg_upap) {
        auth_state = s_up;
        if (auth_script_state == s_down && auth_script_pid == 0) {
            auth_script_state = s_up;
            auth_script(_PATH_AUTHUP);
        }
    }

    /*
     * Process extra options from the secrets file
     */
    if (extra_options != NULL) {
        option_source = (char *)extra_opt_filename;
        option_line = extra_opt_line;
        (void) options_from_list(extra_options, 1);
        free_wordlist(extra_options);
        extra_options = NULL;
    }

#ifdef CBCP_SUPPORT
    /*
     * If we negotiated callback, do it now.
     */
    if (go->neg_cbcp) {
        new_phase(PHASE_CALLBACK);
        (*cbcp_protent.open)(unit);
        return;
    }
#endif

    start_networks();
}

void
start_networks()
{
    int i;
    struct protent *protp;

    new_phase(PHASE_NETWORK);

#ifdef HAVE_MULTILINK
    if (multilink) {
        if (mp_join_bundle()) {
            if (updetach && !nodetach)
                detach();
            return;
        }
    }
#endif /* HAVE_MULTILINK */

#if 0
    if (!demand)
        set_filters(&pass_filter, &active_filter);
#endif
    for (i = 0; (protp = protocols[i]) != NULL; ++i)
        if (protp->protocol < 0xC000 && protp->enabled_flag
            && protp->open != NULL) {
            (*protp->open)(0);
            if (protp->protocol != PPP_CCP)
                ++num_np_open;
        }

    if (num_np_open == 0)
        /* nothing to do */
        lcp_close(0, "No network protocols running");
}

/*
 * The peer has failed to authenticate himself using `protocol'.
 */
/*ARGSUSED*/
void
auth_peer_fail(unit, protocol)
    int unit, protocol;
{
    /*
     * Authentication failure: take the link down
     */
    lcp_close(unit, "Authentication failed");
    status = EXIT_PEER_AUTH_FAILED;
}

/*
 * The peer has been successfully authenticated using `protocol'.
 */
void
auth_peer_success(unit, protocol, name, namelen)
    int unit, protocol;
    char *name;
    int namelen;
{
    int bit;

    switch (protocol) {
    case PPP_CHAP:
        bit = CHAP_PEER;
        break;
    case PPP_PAP:
        bit = PAP_PEER;
        break;
    default:
        warn("auth_peer_success: unknown protocol %x", protocol);
        return;
    }

    /*
     * Save the authenticated name of the peer for later.
     */
    if (namelen > sizeof(peer_authname) - 1)
        namelen = sizeof(peer_authname) - 1;
    BCOPY(name, peer_authname, namelen);
    peer_authname[namelen] = '\0';
    script_setenv("PEERNAME", peer_authname, 0);

    /*
     * If there is no more authentication still to be done,
     * proceed to the network (or callback) phase.
     */
    if ((auth_pending[unit] &= ~bit) == 0)
        network_phase(unit);
}

/*
 * We have failed to authenticate ourselves to the peer using `protocol'.
 */
/*ARGSUSED*/
void
auth_withpeer_fail(unit, protocol)
    int unit, protocol;
{
    if (passwd_from_file)
        BZERO(passwd, MAXSECRETLEN);
    /*
     * We've failed to authenticate ourselves to our peer.
     * Some servers keep sending CHAP challenges, but there
     * is no point in persisting without any way to get updated
     * authentication secrets.
     */
    lcp_close(unit, "Failed to authenticate ourselves to peer");
    status = EXIT_AUTH_TOPEER_FAILED;
}

/*
 * We have successfully authenticated ourselves with the peer using `protocol'.
 */
void
auth_withpeer_success(unit, protocol)
    int unit, protocol;
{
    int bit;

    switch (protocol) {
    case PPP_CHAP:
        bit = CHAP_WITHPEER;
        break;
    case PPP_PAP:
        if (passwd_from_file)
            BZERO(passwd, MAXSECRETLEN);
        bit = PAP_WITHPEER;
        break;
    default:
        warn("auth_withpeer_success: unknown protocol %x", protocol);
        bit = 0;
    }

    /*
     * If there is no more authentication still being done,
     * proceed to the network (or callback) phase.
     */
    if ((auth_pending[unit] &= ~bit) == 0)
        network_phase(unit);
}


/*
 * np_up - a network protocol has come up.
 */
/*ARGSUSED*/
void
np_up(unit, proto)
    int unit, proto;
{
    int tlim;

    if (num_np_up == 0) {
        /*
         * At this point we consider that the link has come up successfully.
         */
        status = EXIT_OK;
        unsuccess = 0;

        peer_nak_auth = unsolicited_nak_auth = peer_reject_auth =
            rejected_peers_auth = naked_peers_auth = 0;
        nak_auth_proto = nak_auth_orig = unsolicit_auth_proto = 
            reject_auth_proto = rejected_auth_proto = naked_auth_orig =
            naked_auth_proto = 0;

        new_phase(PHASE_RUNNING);

        if (idle_time_hook != NULL)
            tlim = (*idle_time_hook)(NULL);
        else
            tlim = idle_time_limit;
        if (tlim > 0)
            TIMEOUT(check_idle, NULL, tlim);

        /*
         * Set a timeout to close the connection once the maximum
         * connect time has expired.
         */
        if (maxconnect > 0) {
            TIMEOUT(connect_time_expired, &lcp_fsm[unit], maxconnect);

            /*
             * Tell LCP to send Time-Remaining packets.  One should be
             * sent out now, at maxconnect-300, at maxconnect-120, and
             * again at maxconnect-30.
             */
            lcp_settimeremaining(unit, maxconnect, maxconnect);
            if (maxconnect > 300)
                lcp_settimeremaining(unit, maxconnect, 300);
            if (maxconnect > 120)
                lcp_settimeremaining(unit, maxconnect, 120);
            if (maxconnect > 30)
                lcp_settimeremaining(unit, maxconnect, 30);
        }

        /*
         * Detach now, if the updetach option was given.
         */
        if (updetach && !nodetach)
            detach();
    }
    ++num_np_up;
}

/*
 * np_down - a network protocol has gone down.
 */
/*ARGSUSED*/
void
np_down(unit, proto)
    int unit, proto;
{
    if (--num_np_up == 0) {
        UNTIMEOUT(check_idle, NULL);
        new_phase(PHASE_NETWORK);
    }
}

/*
 * np_finished - a network protocol has finished using the link.
 */
/*ARGSUSED*/
void
np_finished(unit, proto)
    int unit, proto;
{
    if (--num_np_open <= 0) {
        /* no further use for the link: shut up shop. */
        lcp_close(0, "No network protocols running");
    }
}

/*
 * check_idle - check whether the link has been idle for long
 * enough that we can shut it down.
 */
/*ARGSUSED*/
static void
check_idle(arg)
    void *arg;
{
    struct ppp_idle idle;
    time_t itime;
    int tlim;

    if (!get_idle_time(0, &idle))
        return;
    if (idle_time_hook != NULL) {
        tlim = (*idle_time_hook)(&idle);
    } else {
        itime = MIN(idle.xmit_idle, idle.recv_idle);
        tlim = idle_time_limit - itime;
    }
    if (tlim <= 0) {
        /* link is idle: shut it down. */
        notice("Terminating connection due to lack of activity.");
        lcp_close(0, "Link inactive");
        need_holdoff = 0;
        status = EXIT_IDLE_TIMEOUT;
    } else {
        TIMEOUT(check_idle, NULL, tlim);
    }
}

/*
 * connect_time_expired - log a message and close the connection.
 */
/*ARGSUSED*/
static void
connect_time_expired(arg)
    void *arg;
{
    fsm *f = (fsm *)arg;

    info("Connect time expired");
    lcp_close(f->unit, "Connect time expired"); /* Close connection */
    status = EXIT_CONNECT_TIME;
}

/*
 * auth_check_options - called to check authentication options.
 */
void
auth_check_options()
{
    lcp_options *wo = &lcp_wantoptions[0];
    int can_auth;
    int lacks_ip;

    /* Default our_name to hostname, and user to our_name */
    if (our_name[0] == '\0' || usehostname)
        (void) strlcpy(our_name, hostname, sizeof(our_name));
    if (user[0] == '\0')
        (void) strlcpy(user, our_name, sizeof(user));

    /*
     * If we have a default route, require the peer to authenticate
     * unless the noauth option was given or the real user is root.
     */
    if (!auth_required && !allow_any_ip && have_route_to(0) && !privileged) {
        auth_required = 1;
        default_auth = 1;
    }

    /* If authentication is required, ask peer for CHAP or PAP. */
    if (auth_required) {
        if (!wo->neg_chap && !wo->neg_mschap && !wo->neg_mschapv2 &&
            !wo->neg_upap) {
            wo->neg_chap = 1;
#ifdef CHAPMS
            wo->neg_mschap = 1;
#endif
#ifdef CHAPMSV2
            wo->neg_mschapv2 = 1;
#endif
            wo->chap_mdtype = CHAP_DIGEST_MD5;
            wo->neg_upap = 1;
        }
    } else {
        wo->neg_chap = 0;
        wo->neg_mschap = 0;
        wo->neg_mschapv2 = 0;
        wo->neg_upap = 0;
    }

    /*
     * Check whether we have appropriate secrets to use
     * to authenticate the peer.
     */
    lacks_ip = 0;
    can_auth = wo->neg_upap && (uselogin || have_pap_secret(&lacks_ip));
    if (!can_auth && (wo->neg_chap || wo->neg_mschap || wo->neg_mschapv2)) {
        can_auth = have_chap_secret((explicit_remote? remote_name: NULL),
                                    our_name, 1, &lacks_ip);
    }

    if (auth_required && !can_auth && noauth_addrs == NULL) {
        if (default_auth) {
            option_error(
"By default the remote system is required to authenticate itself");
            option_error(
"(because this system has a default route to the Internet)");
        } else if (explicit_remote)
            option_error(
"The remote system (%s) is required to authenticate itself",
                         remote_name);
        else
            option_error(
"The remote system is required to authenticate itself");
        option_error(
"but I couldn't find any suitable secret (password) for it to use to do so.");
        if (lacks_ip)
            option_error(
"(None of the available passwords would let it use an IP address.)");

        exit(1);
    }
}

/*
 * auth_reset - called when LCP is starting negotiations to recheck
 * authentication options, i.e. whether we have appropriate secrets
 * to use for authenticating ourselves and/or the peer.
 */
void
auth_reset(unit)
    int unit;
{
    lcp_options *go = &lcp_gotoptions[unit];
    lcp_options *ao = &lcp_allowoptions[unit];
    int havesecret;

    ao->neg_upap = !refuse_pap && (passwd[0] != '\0' || get_pap_passwd(NULL));

    havesecret = passwd[0] != '\0' ||
        have_chap_secret(user, (explicit_remote? remote_name: NULL), 0, NULL);
    ao->neg_chap = !refuse_chap && havesecret;
    ao->neg_mschap = !refuse_mschap && havesecret;
    ao->neg_mschapv2 = !refuse_mschapv2 && havesecret;
    if (ao->neg_chap)
        ao->chap_mdtype = CHAP_DIGEST_MD5;
    else if (ao->neg_mschap)
        ao->chap_mdtype = CHAP_MICROSOFT;
    else
        ao->chap_mdtype = CHAP_MICROSOFT_V2;

    if (go->neg_upap && !uselogin && !have_pap_secret(NULL))
        go->neg_upap = 0;
    if (go->neg_chap || go->neg_mschap || go->neg_mschapv2) {
        havesecret = have_chap_secret((explicit_remote? remote_name: NULL),
                our_name, 1, NULL);
        if (!havesecret)
            go->neg_chap = go->neg_mschap = go->neg_mschapv2 = 0;
        else if (go->neg_chap)
            go->chap_mdtype = CHAP_DIGEST_MD5;
        else if (go->neg_mschap)
            go->chap_mdtype = CHAP_MICROSOFT;
        else
            go->chap_mdtype = CHAP_MICROSOFT_V2;
    }
}


/*
 * check_passwd - Check the user name and passwd against the PAP secrets
 * file.  If requested, also check against the system password database,
 * and login the user if OK.
 *
 * returns:
 *      UPAP_AUTHNAK: Authentication failed.
 *      UPAP_AUTHACK: Authentication succeeded.
 * In either case, msg points to an appropriate message.
 */
int
check_passwd(unit, auser, userlen, apasswd, passwdlen, msg)
    int unit;
    char *auser;
    int userlen;
    char *apasswd;
    int passwdlen;
    char **msg;
{
    int ret;
    char *filename;
    FILE *f;
    struct wordlist *addrs = NULL, *opts = NULL;
    char passwd[256], user[256];
    char secret[MAXWORDLEN];
    static int attempts = 0;

    /*
     * Make copies of apasswd and auser, then null-terminate them.
     * If there are unprintable characters in the password, make
     * them visible.
     */
    (void) slprintf(passwd, sizeof(passwd), "%.*v", passwdlen, apasswd);
    (void) slprintf(user, sizeof(user), "%.*v", userlen, auser);
    *msg = "";

    /*
     * Check if a plugin wants to handle this.
     */
    if (pap_auth_hook != NULL) {
        /* Set a default and allow the plug-in to change it. */
        extra_opt_filename = "plugin";
        extra_opt_line = 0;
        ret = (*pap_auth_hook)(user, passwd, msg, &addrs, &opts);
        if (ret >= 0) {
            if (ret > 0)
                set_allowed_addrs(unit, addrs, opts);
            BZERO(passwd, sizeof(passwd));
            if (addrs != NULL)
                free_wordlist(addrs);
            return ret? UPAP_AUTHACK: UPAP_AUTHNAK;
        }
    }

    /*
     * Open the file of pap secrets and scan for a suitable secret
     * for authenticating this user.
     */
    filename = _PATH_UPAPFILE;
    addrs = opts = NULL;
    ret = UPAP_AUTHNAK;
    f = fopen(filename, "r");
    if (f == NULL) {
        error("Can't open PAP password file %s: %m", filename);

    } else {
        check_access(f, filename);
        if (scan_authfile(f, user, our_name, secret, &addrs, &opts, filename) < 0) {
            warn("no PAP secret found for %s", user);
            if (scan_server_match_failed[0] != '\0')
                warn("possible configuration error: local name is %q, but "
                    "found %q instead", our_name, scan_server_match_failed);
        } else if (secret[0] != '\0') {
            /* password given in pap-secrets - must match */
            if ((!cryptpap && strcmp(passwd, secret) == 0)
                || strcmp(crypt(passwd, secret), secret) == 0)
                ret = UPAP_AUTHACK;
            else
                warn("PAP authentication failure for %s", user);
        } else if (uselogin) {
            /* empty password in pap-secrets and login option */
            ret = plogin(user, passwd, msg);
            if (ret == UPAP_AUTHNAK)
                warn("PAP login failure for %s", user);
        } else {
            /* empty password in pap-secrets and login option not used */
            ret = UPAP_AUTHACK;
        }
        (void) fclose(f);
    }

    if (ret == UPAP_AUTHNAK) {
        if (**msg == '\0')
            *msg = "Login incorrect";
        /*
         * Frustrate passwd stealer programs.
         * Allow 10 tries, but start backing off after 3 (stolen from login).
         * On 10'th, drop the connection.
         */
        if (attempts++ >= 10) {
            warn("%d LOGIN FAILURES ON %s, %s", attempts, devnam, user);
            lcp_close(unit, "login failed");
        }
        if (attempts > 3)
            (void) sleep((u_int) (attempts - 3) * 5);
        if (opts != NULL)
            free_wordlist(opts);

    } else {
        attempts = 0;                   /* Reset count */
        if (**msg == '\0')
            *msg = "Login ok";
        set_allowed_addrs(unit, addrs, opts);
    }

    if (addrs != NULL)
        free_wordlist(addrs);
    BZERO(passwd, sizeof(passwd));
    BZERO(secret, sizeof(secret));

    return ret;
}

/*
 * This function is needed for PAM.
 */

#ifdef ALLOW_PAM
/* Static variables used to communicate between the conversation function
 * and the server_login function 
 */
static char *PAM_username;
static char *PAM_password;
static int PAM_error = 0;
static pam_handle_t *pamh = NULL;

/* PAM conversation function
 * Here we assume (for now, at least) that echo on means login name, and
 * echo off means password.
 */

/*ARGSUSED*/
static int PAM_conv (int num_msg,
#ifndef SOL2
    const
#endif
    struct pam_message **msg, struct pam_response **resp, void *appdata_ptr)
{
    int replies = 0;
    struct pam_response *reply = NULL;

#define COPY_STRING(s) (s) ? strdup(s) : NULL

    reply = malloc(sizeof(struct pam_response) * num_msg);
    if (reply == NULL)
        return PAM_CONV_ERR;

    for (replies = 0; replies < num_msg; replies++) {
        switch (msg[replies]->msg_style) {
            case PAM_PROMPT_ECHO_ON:
                reply[replies].resp_retcode = PAM_SUCCESS;
                reply[replies].resp = COPY_STRING(PAM_username);
                /* PAM frees resp */
                break;
            case PAM_PROMPT_ECHO_OFF:
                reply[replies].resp_retcode = PAM_SUCCESS;
                reply[replies].resp = COPY_STRING(PAM_password);
                /* PAM frees resp */
                break;
            case PAM_TEXT_INFO:
                /* fall through */
            case PAM_ERROR_MSG:
                /* ignore it, but pam still wants a NULL response... */
                reply[replies].resp_retcode = PAM_SUCCESS;
                reply[replies].resp = NULL;
                break;
            default:       
                /* Must be an error of some sort... */
                free (reply);
                PAM_error = 1;
                return PAM_CONV_ERR;
        }
    }
    *resp = reply;     
    return PAM_SUCCESS;
}

static struct pam_conv PAM_conversation = {
        PAM_conv, NULL
};
#endif  /* ALLOW_PAM */

/*
 * plogin - Check the user name and password against the system
 * password database, and login the user if OK.
 *
 * returns:
 *      UPAP_AUTHNAK: Login failed.
 *      UPAP_AUTHACK: Login succeeded.
 * In either case, msg points to an appropriate message.
 */

static int
plogin(user, passwd, msg)
    char *user;
    char *passwd;
    char **msg;
{
    char *tty;
#ifdef HAS_SHADOW
    struct spwd *spwd;
#endif
    struct passwd *pw = NULL;

#ifdef ALLOW_PAM
    int pam_error;

    if (use_pam) {
        if (debug)
            dbglog("using PAM for user authentication");
        pam_error = pam_start ("ppp", user, &PAM_conversation, &pamh);
        if (pam_error != PAM_SUCCESS) {
            *msg = (char *) pam_strerror (pamh, pam_error);
            reopen_log();
            return UPAP_AUTHNAK;
        }
        /*
         * Define the fields for the credential validation
         */

        PAM_username = user;
        PAM_password = passwd;
        PAM_error = 0;
        /* this might be useful to some modules; required for Solaris */
        tty = devnam;
        if (*tty == '\0')
            tty = ppp_devnam;
        (void) pam_set_item(pamh, PAM_TTY, tty);
#ifdef PAM_RHOST
        (void) pam_set_item(pamh, PAM_RHOST, "");
#endif

        /*
         * Validate the user
         */
        pam_error = pam_authenticate (pamh, PAM_SILENT);
        if (pam_error == PAM_SUCCESS && !PAM_error) {    
            pam_error = pam_acct_mgmt (pamh, PAM_SILENT);
            if (pam_error == PAM_SUCCESS)
                (void) pam_open_session (pamh, PAM_SILENT);
        }

        *msg = (char *) pam_strerror (pamh, pam_error);

        /*
         * Clean up the mess
         */
        reopen_log();   /* apparently the PAM stuff does closelog() */
        PAM_username = NULL;
        PAM_password = NULL;
        if (pam_error != PAM_SUCCESS)
            return UPAP_AUTHNAK;
    } else
#endif /* ALLOW_PAM */

    {
        if (debug) {
#ifdef HAS_SHADOW
            dbglog("using passwd/shadow for user authentication");
#else
            dbglog("using passwd for user authentication");
#endif
        }
/*
 * Use the non-PAM methods directly
 */

        pw = getpwnam(user);

        endpwent();
        if (pw == NULL)
            return (UPAP_AUTHNAK);

#ifdef HAS_SHADOW
        spwd = getspnam(user);
        endspent();
        if (spwd != NULL) {
            /* check the age of the password entry */
            long now = time(NULL) / 86400L;

            if ((spwd->sp_expire > 0 && now >= spwd->sp_expire)
                || ((spwd->sp_max >= 0 && spwd->sp_max < 10000)
                && spwd->sp_lstchg >= 0
                && now >= spwd->sp_lstchg + spwd->sp_max)) {
                warn("Password for %s has expired", user);
                return (UPAP_AUTHNAK);
            }
            pw->pw_passwd = spwd->sp_pwdp;
        }
#endif

    /*
     * If no passwd, don't let them login.
     */
        if (pw->pw_passwd == NULL || strlen(pw->pw_passwd) < 2 ||
            strcmp(crypt(passwd, pw->pw_passwd), pw->pw_passwd) != 0)
            return (UPAP_AUTHNAK);
    }

    /*
     * Write a wtmp entry for this user.
     */

    tty = devnam;
    if (strncmp(tty, "/dev/", 5) == 0)
        tty += 5;
    logwtmp(tty, user, remote_name);            /* Add wtmp login entry */

    info("user %s logged in", user);
    logged_in = 1;

    return (UPAP_AUTHACK);
}

/*
 * plogout - Logout the user.
 */
static void
plogout()
{
    char *tty;

#ifdef ALLOW_PAM
    int pam_error;

    if (use_pam) {
        if (pamh != NULL) {
            pam_error = pam_close_session (pamh, PAM_SILENT);
            (void) pam_end (pamh, pam_error);
            pamh = NULL;
        }
        /* Apparently the pam stuff does closelog(). */
        reopen_log();
    } else
#endif /* ALLOW_PAM */   

    {
        tty = devnam;
        if (strncmp(tty, "/dev/", 5) == 0)
            tty += 5;
        /* Wipe out utmp logout entry */
        logwtmp(tty, "", "");
    }
    logged_in = 0;
}


/*
 * null_login - Check if a username of "" and a password of "" are
 * acceptable, and iff so, set the list of acceptable IP addresses
 * and return 1.
 */
static int
null_login(unit)
    int unit;
{
    char *filename;
    FILE *f;
    int i, ret;
    struct wordlist *addrs, *opts;
    char secret[MAXWORDLEN];

    /*
     * Open the file of pap secrets and scan for a suitable secret.
     */
    filename = _PATH_UPAPFILE;
    addrs = NULL;
    f = fopen(filename, "r");
    if (f == NULL)
        return 0;
    check_access(f, filename);

    i = scan_authfile(f, "", our_name, secret, &addrs, &opts, filename);
    ret = i >= 0 && secret[0] == '\0';
    BZERO(secret, sizeof(secret));

    if (ret)
        set_allowed_addrs(unit, addrs, opts);
    else if (opts != NULL)
        free_wordlist(opts);
    if (addrs != NULL)
        free_wordlist(addrs);

    (void) fclose(f);
    return ret;
}


/*
 * get_pap_passwd - get a password for authenticating ourselves with
 * our peer using PAP.  Returns 1 on success, 0 if no suitable password
 * could be found.
 * Assumes passwd points to MAXSECRETLEN bytes of space (if non-null).
 */
static int
get_pap_passwd(passwd)
    char *passwd;
{
    char *filename;
    FILE *f;
    int ret;
    char secret[MAXWORDLEN];

    /*
     * Check whether a plugin wants to supply this.
     */
    if (pap_passwd_hook != NULL) {
        ret = (*pap_passwd_hook)(user, passwd);
        if (ret >= 0)
            return ret;
    }

    filename = _PATH_UPAPFILE;
    f = fopen(filename, "r");
    if (f == NULL)
        return 0;
    check_access(f, filename);
    ret = scan_authfile(f, user,
                        (remote_name[0] != '\0' ? remote_name: NULL),
                        secret, NULL, NULL, filename);
    (void) fclose(f);
    if (ret < 0)
        return 0;
    if (passwd != NULL)
        (void) strlcpy(passwd, secret, MAXSECRETLEN);
    BZERO(secret, sizeof(secret));
    return 1;
}


/*
 * have_pap_secret - check whether we have a PAP file with any
 * secrets that we could possibly use for authenticating the peer.
 */
static int
have_pap_secret(lacks_ipp)
    int *lacks_ipp;
{
    FILE *f;
    int ret;
    char *filename;
    struct wordlist *addrs;

    /* let the plugin decide, if there is one */
    if (pap_check_hook != NULL) {
        ret = (*pap_check_hook)();
        if (ret >= 0)
            return ret;
    }

    filename = _PATH_UPAPFILE;
    f = fopen(filename, "r");
    if (f == NULL)
        return 0;

    ret = scan_authfile(f, (explicit_remote? remote_name: NULL), our_name,
                        NULL, &addrs, NULL, filename);
    (void) fclose(f);
    if (ret >= 0 && !some_ip_ok(addrs)) {
        if (lacks_ipp != NULL)
            *lacks_ipp = 1;
        ret = -1;
    }
    if (addrs != NULL)
        free_wordlist(addrs);

    return ret >= 0;
}


/*
 * have_chap_secret - check whether we have a CHAP file with a secret
 * that we could possibly use for authenticating `client' on `server'.
 * Either or both can be the null string, meaning we don't know the
 * identity yet.
 */
static int
have_chap_secret(client, server, need_ip, lacks_ipp)
    char *client;
    char *server;
    int need_ip;
    int *lacks_ipp;
{
    FILE *f;
    int ret;
    char *filename;
    struct wordlist *addrs;

    filename = _PATH_CHAPFILE;
    f = fopen(filename, "r");
    if (f == NULL)
        return 0;

    if (client != NULL && client[0] == '\0')
        client = NULL;
    if (server != NULL && server[0] == '\0')
        server = NULL;

    ret = scan_authfile(f, client, server, NULL, &addrs, NULL, filename);
    (void) fclose(f);
    if (ret >= 0 && need_ip && !some_ip_ok(addrs)) {
        if (lacks_ipp != NULL)
            *lacks_ipp = 1;
        ret = -1;
    }
    if (addrs != NULL)
        free_wordlist(addrs);

    return ret >= 0;
}


/*
 * get_secret - open the CHAP secret file and return the secret
 * for authenticating the given client on the given server.
 *
 *      "am_server" means that we're the authenticator (demanding
 *      identity from the peer).
 *
 *      "!am_server" means that we're the authenticatee (supplying
 *      identity to the peer).
 */
int
get_secret(unit, client, server, secret, secret_len, am_server)
    int unit;
    char *client;
    char *server;
    char *secret;
    int *secret_len;
    int am_server;
{
    FILE *f;
    int ret, len;
    char *filename;
    struct wordlist *addrs, *opts;
    char secbuf[MAXWORDLEN];

    /*
     * Support the 'password' option on authenticatee only in order to
     * avoid obvious security problem (authenticator and authenticatee
     * within a given implementation must never share secrets).
     */
    if (!am_server && passwd[0] != '\0') {
        (void) strlcpy(secbuf, passwd, sizeof(secbuf));
    } else {
        filename = _PATH_CHAPFILE;
        addrs = NULL;
        secbuf[0] = '\0';

        f = fopen(filename, "r");
        if (f == NULL) {
            error("Can't open chap secret file %s: %m", filename);
            return 0;
        }
        check_access(f, filename);

        ret = scan_authfile(f, client, server, secbuf, &addrs, &opts,
            filename);
        (void) fclose(f);
        if (ret < 0) {
            if (scan_server_match_failed[0] != '\0')
                warn("possible configuration error: local name is %q, but "
                    "found %q instead", our_name, scan_server_match_failed);
            return 0;
        }

        /* Only the authenticator cares about limiting peer addresses. */
        if (am_server)
            set_allowed_addrs(unit, addrs, opts);
        else if (opts != NULL)
            free_wordlist(opts);
        if (addrs != NULL)
            free_wordlist(addrs);
    }

    len = strlen(secbuf);
    if (len > MAXSECRETLEN) {
        error("Secret for %s on %s is too long", client, server);
        len = MAXSECRETLEN;
    }
    /* Do not leave a temporary copy of the secret on the stack. */
    BCOPY(secbuf, secret, len);
    BZERO(secbuf, sizeof(secbuf));
    *secret_len = len;

    return 1;
}

/*
 * set_allowed_addrs() - set the list of allowed addresses.
 * The caller must also look for `--' indicating options to apply for
 * this peer and leaves the following words in extra_options.
 */
static void
set_allowed_addrs(unit, addrs, opts)
    int unit;
    struct wordlist *addrs;
    struct wordlist *opts;
{
    int n;
    struct wordlist *ap, **pap;
    struct permitted_ip *ip;
    char *ptr_word, *ptr_mask;
    struct hostent *hp;
    struct netent *np;
    u_int32_t a, mask, newmask, ah, offset;
    struct ipcp_options *wo = &ipcp_wantoptions[unit];
    u_int32_t suggested_ip = 0;
    int err_num;

    free(addresses[unit]);
    addresses[unit] = NULL;
    if (extra_options != NULL)
        free_wordlist(extra_options);
    extra_options = opts;

    /*
     * Count the number of IP addresses given.
     */
    for (n = 0, pap = &addrs; (ap = *pap) != NULL; pap = &ap->next)
        ++n;
    if (n == 0)
        return;
    ip = (struct permitted_ip *) malloc((n + 1) * sizeof(struct permitted_ip));
    if (ip == NULL)
        return;

    n = 0;
    for (ap = addrs; ap != NULL; ap = ap->next) {
        /* "-" means no addresses authorized, "*" means any address allowed */
        ptr_word = ap->word;
        if (strcmp(ptr_word, "-") == 0)
            break;
        if (strcmp(ptr_word, "*") == 0) {
            ip[n].permit = 1;
            ip[n].base = ip[n].mask = 0;
            ++n;
            break;
        }

        ip[n].permit = 1;
        if (*ptr_word == '!') {
            ip[n].permit = 0;
            ++ptr_word;
        }

        mask = ~ (u_int32_t) 0;
        offset = 0;
        ptr_mask = strchr (ptr_word, '/');
        if (ptr_mask != NULL) {
            int bit_count;
            char *endp;

            bit_count = (int) strtol (ptr_mask+1, &endp, 10);
            if (bit_count <= 0 || bit_count > 32) {
                warn("invalid address length %v in authorized address list",
                     ptr_mask+1);
                continue;
            }
            bit_count = 32 - bit_count; /* # bits in host part */
            if (*endp == '+') {
                offset = ifunit + 1;
                ++endp;
            }
            if (*endp != '\0') {
                warn("invalid address length syntax: %v", ptr_mask+1);
                continue;
            }
            *ptr_mask = '\0';
            mask <<= bit_count;
        }

        /* Try to interpret value as host name or numeric address first */
        hp = getipnodebyname(ptr_word, AF_INET, 0, &err_num);
        if (hp != NULL) {
            (void) memcpy(&a, hp->h_addr, sizeof(a));
            freehostent(hp);
        } else {
            char *cp = ptr_word + strlen(ptr_word);
            if (cp > ptr_word)
                cp--;
            if (*cp == '+') {
                offset = ifunit + 1;
                *cp = '\0';
            }
            np = getnetbyname (ptr_word);
            if (np != NULL && np->n_addrtype == AF_INET) {
                ah = np->n_net;
                newmask = (u_int32_t)~0;
                if ((ah & 0xff000000ul) == 0)
                    ah <<= 8, newmask <<= 8;
                if ((ah & 0xff000000ul) == 0)
                    ah <<= 8, newmask <<= 8;
                if ((ah & 0xff000000ul) == 0)
                    ah <<= 8, newmask <<= 8;
                if (ptr_mask == NULL)
                    mask = newmask;
                a = htonl(ah);
            }
        }

        if (ptr_mask != NULL)
            *ptr_mask = '/';

        if (a == (u_int32_t)-1L) {
            warn("unknown host %s in auth. address list", ap->word);
            continue;
        }
        if (offset != 0) {
            if (offset >= ~mask) {
                warn("interface unit %d too large for subnet %v",
                     ifunit, ptr_word);
                continue;
            }
            a = htonl((ntohl(a) & mask) + offset);
            mask = ~(u_int32_t)0;
        }
        ip[n].mask = htonl(mask);
        ip[n].base = a & ip[n].mask;
        ++n;
        if (~mask == 0 && suggested_ip == 0)
            suggested_ip = a;
    }

    /* Sentinel value at end of list */
    ip[n].permit = 0;           /* make the last entry forbid all addresses */
    ip[n].base = 0;             /* to terminate the list */
    ip[n].mask = 0;

    addresses[unit] = ip;

    /*
     * If the address given for the peer isn't authorized, or if
     * the user hasn't given one, AND there is an authorized address
     * which is a single host, then use that if we find one.
     */
    if (suggested_ip != 0
        && (wo->hisaddr == 0 || !auth_ip_addr(unit, wo->hisaddr)))
        wo->hisaddr = suggested_ip;
}

/*
 * 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_int32_t addr;
{
    int ok;

    /* don't allow loopback or multicast address */
    if (bad_ip_adrs(addr))
        return 0;

    if (addresses[unit] != NULL) {
        ok = ip_addr_check(addr, addresses[unit]);
        if (ok >= 0)
            return ok;
    }
    if (auth_required)
        return 0;               /* no addresses authorized */
    return allow_any_ip || privileged || !have_route_to(addr);
}

static int
ip_addr_check(addr, addrs)
    u_int32_t addr;
    struct permitted_ip *addrs;
{
    /* This loop is safe because of the sentinel value in set_allowed_addrs */
    for (; ; ++addrs)
        if ((addr & addrs->mask) == addrs->base)
            return addrs->permit;
}

/*
 * 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_int32_t addr;
{
    addr = ntohl(addr);
    return 
#ifndef ALLOW_127_NET
        (addr >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
#endif
#ifndef ALLOW_0_NET
        ((addr >> IN_CLASSA_NSHIFT) == 0 && addr != 0) ||
#endif
        IN_MULTICAST(addr);
}

/*
 * some_ip_ok - check a wordlist to see if it authorizes any
 * IP address(es).
 */
static int
some_ip_ok(addrs)
    struct wordlist *addrs;
{
    for (; addrs != NULL; addrs = addrs->next) {
        if (addrs->word[0] == '-')
            break;
        if (addrs->word[0] != '!')
            return 1;           /* some IP address is allowed */
    }
    return 0;
}

/*
 * check_access - complain if a secret file has too-liberal permissions.
 */
static void
check_access(f, filename)
    FILE *f;
    char *filename;
{
    struct stat sbuf;

    if (fstat(fileno(f), &sbuf) < 0) {
        warn("cannot stat secret file %s: %m", filename);
    } else if ((sbuf.st_mode & (S_IRWXG | S_IRWXO)) != 0) {
        warn("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 up to a "--" (i.e. address
 * authorization info) are placed in a wordlist and returned in
 * *addrs.  Any following words (extra options) are placed in a
 * wordlist and returned in *opts.  If opts is NULL, these are just
 * discarded.  Otherwise, the extra_opt_* variables are set to
 * indicate the source of the options.
 *
 * We assume secret is NULL or points to MAXWORDLEN bytes of space.
 */
static int
scan_authfile(f, client, server, secret, addrs, opts, filename)
    FILE *f;
    char *client;
    char *server;
    char *secret;
    struct wordlist **addrs;
    struct wordlist **opts;
    char *filename;
{
    int newline, xxx, sline;
    int got_flag, best_flag;
    FILE *sf;
    struct wordlist *ap, *addr_list, *alist, **app;
    char word[MAXWORDLEN];
    char atfile[MAXWORDLEN];
    char lsecret[MAXWORDLEN];

    scan_server_match_failed[0] = '\0';

    if (addrs != NULL)
        *addrs = NULL;
    if (opts != NULL)
        *opts = NULL;
    addr_list = NULL;
    option_line = 0;
    if (!getword(f, word, &newline, filename)) {
        if (debug)
            dbglog("%s is apparently empty", 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 */

        sline = option_line;
        /*
         * 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 (!ISWILD(word)) {
            if (server != NULL && strcmp(word, server) != 0) {
                (void) strcpy(scan_server_match_failed, word);
                continue;
            }
            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.
         * Because the secrets files are modifiable only by root,
         * it's safe to open this file as root.  One small addition --
         * if open fails, we try as the regular user; just in case
         * it's over NFS and not root-equivalent.
         */
        if (word[0] == '@') {
            (void) strlcpy(atfile, word+1, sizeof(atfile));
            if ((sf = fopen(atfile, "r")) == NULL) {
                (void) seteuid(getuid());
                sf = fopen(atfile, "r");
                (void) seteuid(0);
            }
            if (sf == NULL) {
                warn("can't open indirect secret file %s: %m", atfile);
                continue;
            }
            check_access(sf, atfile);
            if (!getword(sf, word, &xxx, atfile)) {
                warn("no secret in indirect secret file %s", atfile);
                (void) fclose(sf);
                continue;
            }
            (void) fclose(sf);
        }
        if (secret != NULL)
            (void) strlcpy(lsecret, word, sizeof(lsecret));

        /*
         * Now read address authorization info and make a wordlist.
         */
        app = &alist;
        for (;;) {
            if (!getword(f, word, &newline, filename) || newline)
                break;
            ap = (struct wordlist *) malloc(sizeof(struct wordlist));
            if (ap == NULL)
                novm("authorized addresses");
            ap->word = strdup(word);
            if (ap->word == NULL)
                novm("authorized addresses");
            *app = ap;
            app = &ap->next;
        }
        *app = NULL;

        /*
         * This is the best so far; remember it.
         */
        best_flag = got_flag;
        if (addr_list != NULL)
            free_wordlist(addr_list);
        addr_list = alist;
        if (secret != NULL)
            (void) strlcpy(secret, lsecret, MAXWORDLEN);

        if (opts != NULL) {
            extra_opt_filename = filename;
            extra_opt_line = sline;
        }

        if (!newline)
            break;
    }

    /* scan for a -- word indicating the start of options */
    for (app = &addr_list; (ap = *app) != NULL; app = &ap->next)
        if (strcmp(ap->word, "--") == 0)
            break;
    /* ap = start of options */
    if (ap != NULL) {
        ap = ap->next;          /* first option */
        free(*app);                     /* free the "--" word */
        *app = NULL;            /* terminate addr list */
    }
    if (opts != NULL)
        *opts = ap;
    else if (ap != NULL)
        free_wordlist(ap);
    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;
    }
}

/*
 * auth_script_done - called when the auth-up or auth-down script
 * has finished.
 */
/*ARGSUSED*/
static void
auth_script_done(arg, status)
    void *arg;
    int status;
{
    auth_script_pid = 0;
    switch (auth_script_state) {
    case s_up:
        if (auth_state == s_down) {
            auth_script_state = s_down;
            auth_script(_PATH_AUTHDOWN);
        }
        break;
    case s_down:
        if (auth_state == s_up) {
            auth_script_state = s_up;
            auth_script(_PATH_AUTHUP);
        }
        break;
    }
}

/*
 * auth_script - execute a script with arguments
 * interface-name peer-name real-user tty speed
 */
static void
auth_script(script)
    char *script;
{
    char strspeed[32];
    struct passwd *pw;
    char struid[32];
    char *user_name;
    char *argv[8];

    if ((pw = getpwuid(getuid())) != NULL && pw->pw_name != NULL)
        user_name = pw->pw_name;
    else {
        (void) slprintf(struid, sizeof(struid), "%d", getuid());
        user_name = struid;
    }
    (void) slprintf(strspeed, sizeof(strspeed), "%d", baud_rate);

    argv[0] = script;
    argv[1] = ifname;
    argv[2] = peer_authname;
    argv[3] = user_name;
    argv[4] = devnam;
    argv[5] = strspeed;
    argv[6] = NULL;

    auth_script_pid = run_program(script, argv, 0, auth_script_done, NULL);
}