xref: /netbsd/src/external/bsd/ppp/dist/pppd/auth.c

/*        $NetBSD: auth.c,v 1.6 2025/01/08 19:59:38 christos Exp $    */

/*
 * auth.c - PPP authentication and phase control.
 *
 * Copyright (c) 1993-2024 Paul Mackerras. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
 * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * Derived from main.c, which is:
 *
 * Copyright (c) 1984-2000 Carnegie Mellon University. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The name "Carnegie Mellon University" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For permission or any legal
 *    details, please contact
 *      Office of Technology Transfer
 *      Carnegie Mellon University
 *      5000 Forbes Avenue
 *      Pittsburgh, PA  15213-3890
 *      (412) 268-4387, fax: (412) 268-7395
 *      tech-transfer@andrew.cmu.edu
 *
 * 4. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by Computing Services
 *     at Carnegie Mellon University (http://www.cmu.edu/computing/)."
 *
 * CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
 * FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/cdefs.h>
__RCSID("$NetBSD: auth.c,v 1.6 2025/01/08 19:59:38 christos Exp $");

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

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

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


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

#ifdef HAVE_CRYPT_H
#include <crypt.h>
#endif

#ifdef SYSTEMD
#include <systemd/sd-daemon.h>
#endif

#include "pppd-private.h"
#include "options.h"
#include "fsm.h"
#include "lcp.h"
#include "ccp.h"
#include "ecp.h"
#include "ipcp.h"
#include "upap.h"
#include "chap.h"
#include "eap.h"
#ifdef PPP_WITH_EAPTLS
#include "eap-tls.h"
#endif
#ifdef PPP_WITH_CBCP
#include "cbcp.h"
#endif
#include "multilink.h"
#include "pathnames.h"
#include "session.h"


/* 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];

/* Records which authentication operations have been completed. */
int auth_done[NUM_PPP];

/* 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;

/* Remote telephone number, if available */
char remote_number[MAXNAMELEN];

/* Wordlist giving remote telephone numbers which may connect. */
static struct wordlist *permitted_numbers;

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

/* 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)(struct ppp_idle *) = NULL;

/* Hook for a plugin to say whether we can possibly authenticate any peer */
pap_check_hook_fn *pap_check_hook = NULL;

/* Hook for a plugin to check the PAP user and password */
pap_auth_hook_fn *pap_auth_hook = NULL;

/* Hook for a plugin to know about the PAP user logout */
pap_logout_hook_fn *pap_logout_hook = NULL;

/* Hook for a plugin to get the PAP password for authenticating us */
pap_passwd_hook_fn *pap_passwd_hook = NULL;

/* Hook for a plugin to say if we can possibly authenticate a peer using CHAP */
chap_check_hook_fn *chap_check_hook = NULL;

/* Hook for a plugin to get the CHAP password for authenticating us */
chap_passwd_hook_fn *chap_passwd_hook = NULL;

#ifdef PPP_WITH_EAPTLS
/* Hook for a plugin to get the EAP-TLS password for authenticating us */
eaptls_passwd_hook_fn *eaptls_passwd_hook = NULL;
#endif

/* Hook for a plugin to say whether it is OK if the peer
   refuses to authenticate. */
int (*null_auth_hook)(struct wordlist **paddrs,
                          struct wordlist **popts) = NULL;

int (*allowed_address_hook)(u_int32_t addr) = NULL;

/* A notifier for when the peer has authenticated itself,
   and we are proceeding to the network phase. */
struct notifier *auth_up_notifier = NULL;

/* A notifier for when the link goes down. */
struct notifier *link_down_notifier = 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;

/*
 * Option variables.
 */
bool uselogin = 0;            /* Use /etc/passwd for checking PAP */
bool session_mgmt = 0;                  /* Do session management (login records) */
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 refuse_eap = 0;                    /* Don't wanna auth. ourselves with EAP */
#ifdef PPP_WITH_CHAPMS
bool refuse_mschap = 0;                 /* Don't wanna auth. ourselves with MS-CHAP */
bool refuse_mschap_v2 = 0;    /* Don't wanna auth. ourselves with MS-CHAPv2 */
#else
bool refuse_mschap = 1;                 /* Don't wanna auth. ourselves with MS-CHAP */
bool refuse_mschap_v2 = 1;    /* Don't wanna auth. ourselves with MS-CHAPv2 */
#endif
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 */
bool explicit_user = 0;                 /* Set if "user" option supplied */
bool explicit_passwd = 0;     /* Set if "password" option supplied */
char remote_name[MAXNAMELEN]; /* Peer's name for authentication */
char path_upapfile[MAXPATHLEN];         /* Pathname of pap-secrets file */
char path_chapfile[MAXPATHLEN];         /* Pathname of chap-secrets file */

#if defined(PPP_WITH_EAPTLS) || defined(PPP_WITH_PEAP)
char *cacert_file  = NULL;  /* CA certificate file (pem format) */
char *ca_path      = NULL;  /* Directory with CA certificates */
char *crl_dir      = NULL;  /* Directory containing CRL files */
char *crl_file     = NULL;  /* Certificate Revocation List (CRL) file (pem format) */
char *max_tls_version = NULL;   /* Maximum TLS protocol version (default=1.2) */
char *tls_verify_method = NULL; /* Verify certificate method */
bool  tls_verify_key_usage = 0; /* Verify peer certificate key usage */
#endif

#if defined(PPP_WITH_EAPTLS)
char *cert_file    = NULL;  /* Client certificate file (pem format) */
char *privkey_file = NULL;  /* Client private key file (pem format) */
char *pkcs12_file  = NULL;  /* Client private key envelope file (pkcs12 format) */
bool need_peer_eap = 0;           /* Require peer to authenticate us */
#endif

static char *fname;           /* name of most recent +ua file */

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

static void network_phase (int);
static void check_idle (void *);
static void connect_time_expired (void *);
static int  null_login (int);
static int  get_pap_passwd (char *);
static int  have_pap_secret (int *);
static int  have_chap_secret (char *, char *, int, int *);
static int  have_srp_secret(char *client, char *server, int need_ip,
    int *lacks_ipp);

#ifdef PPP_WITH_EAPTLS
static int  have_eaptls_secret_server
(char *client, char *server, int need_ip, int *lacks_ipp);
static int  have_eaptls_secret_client (char *client, char *server);
static int  scan_authfile_eaptls(FILE * f, char *client, char *server,
                                     char *cli_cert, char *serv_cert,
                                     char *ca_cert, char *pk,
                                     struct wordlist ** addrs,
                                     struct wordlist ** opts,
                                     char *filename, int flags);
#endif

static int  ip_addr_check (u_int32_t, struct permitted_ip *);
static int  scan_authfile(FILE *, char *, char *, char *,
                                struct wordlist **, struct wordlist **,
                                char *, int);
static void free_wordlist (struct wordlist *);
static void auth_script (char *);
static void auth_script_done (void *);
static void set_allowed_addrs (int, struct wordlist *, struct wordlist *);
static int  some_ip_ok (struct wordlist *);
static int  setupapfile (char **);
static int  privgroup (char **);
static int  set_noauth_addr (char **);
static int  set_permitted_number (char **);
static void check_access (FILE *, char *);
static int  wordlist_count (struct wordlist *);
static void check_maxoctets (void *);

/*
 * Authentication-related options.
 */
struct option auth_options[] = {
    { "auth", o_bool, &auth_required,
      "Require authentication from peer", OPT_PRIO | 1 },
    { "noauth", o_bool, &auth_required,
      "Don't require peer to authenticate", OPT_PRIOSUB | OPT_PRIV,
      &allow_any_ip },
    { "require-pap", o_bool, &lcp_wantoptions[0].neg_upap,
      "Require PAP authentication from peer",
      OPT_PRIOSUB | 1, &auth_required },
    { "+pap", o_bool, &lcp_wantoptions[0].neg_upap,
      "Require PAP authentication from peer",
      OPT_ALIAS | OPT_PRIOSUB | 1, &auth_required },
    { "require-chap", o_bool, &auth_required,
      "Require CHAP authentication from peer",
      OPT_PRIOSUB | OPT_A2OR | MDTYPE_MD5,
      &lcp_wantoptions[0].chap_mdtype },
    { "+chap", o_bool, &auth_required,
      "Require CHAP authentication from peer",
      OPT_ALIAS | OPT_PRIOSUB | OPT_A2OR | MDTYPE_MD5,
      &lcp_wantoptions[0].chap_mdtype },
#ifdef PPP_WITH_CHAPMS
    { "require-mschap", o_bool, &auth_required,
      "Require MS-CHAP authentication from peer",
      OPT_PRIOSUB | OPT_A2OR | MDTYPE_MICROSOFT,
      &lcp_wantoptions[0].chap_mdtype },
    { "+mschap", o_bool, &auth_required,
      "Require MS-CHAP authentication from peer",
      OPT_ALIAS | OPT_PRIOSUB | OPT_A2OR | MDTYPE_MICROSOFT,
      &lcp_wantoptions[0].chap_mdtype },
    { "require-mschap-v2", o_bool, &auth_required,
      "Require MS-CHAPv2 authentication from peer",
      OPT_PRIOSUB | OPT_A2OR | MDTYPE_MICROSOFT_V2,
      &lcp_wantoptions[0].chap_mdtype },
    { "+mschap-v2", o_bool, &auth_required,
      "Require MS-CHAPv2 authentication from peer",
      OPT_ALIAS | OPT_PRIOSUB | OPT_A2OR | MDTYPE_MICROSOFT_V2,
      &lcp_wantoptions[0].chap_mdtype },
#endif

    { "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", OPT_ALIAS | 1 },
    { "refuse-chap", o_bool, &refuse_chap,
      "Don't agree to auth to peer with CHAP",
      OPT_A2CLRB | MDTYPE_MD5,
      &lcp_allowoptions[0].chap_mdtype },
    { "-chap", o_bool, &refuse_chap,
      "Don't allow CHAP authentication with peer",
      OPT_ALIAS | OPT_A2CLRB | MDTYPE_MD5,
      &lcp_allowoptions[0].chap_mdtype },
#ifdef PPP_WITH_CHAPMS
    { "refuse-mschap", o_bool, &refuse_mschap,
      "Don't agree to auth to peer with MS-CHAP",
      OPT_A2CLRB | MDTYPE_MICROSOFT,
      &lcp_allowoptions[0].chap_mdtype },
    { "-mschap", o_bool, &refuse_mschap,
      "Don't allow MS-CHAP authentication with peer",
      OPT_ALIAS | OPT_A2CLRB | MDTYPE_MICROSOFT,
      &lcp_allowoptions[0].chap_mdtype },
    { "refuse-mschap-v2", o_bool, &refuse_mschap_v2,
      "Don't agree to auth to peer with MS-CHAPv2",
      OPT_A2CLRB | MDTYPE_MICROSOFT_V2,
      &lcp_allowoptions[0].chap_mdtype },
    { "-mschap-v2", o_bool, &refuse_mschap_v2,
      "Don't allow MS-CHAPv2 authentication with peer",
      OPT_ALIAS | OPT_A2CLRB | MDTYPE_MICROSOFT_V2,
      &lcp_allowoptions[0].chap_mdtype },
#endif

    { "require-eap", o_bool, &lcp_wantoptions[0].neg_eap,
      "Require EAP authentication from peer", OPT_PRIOSUB | 1,
      &auth_required },
    { "refuse-eap", o_bool, &refuse_eap,
      "Don't agree to authenticate to peer with EAP", 1 },

    { "name", o_string, our_name,
      "Set local name for authentication",
      OPT_PRIO | OPT_PRIV | OPT_STATIC, NULL, MAXNAMELEN },

    { "+ua", o_special, (void *)setupapfile,
      "Get PAP user and password from file",
      OPT_PRIO | OPT_A2STRVAL, &fname },

    { "user", o_string, user,
      "Set name for auth with peer", OPT_PRIO | OPT_STATIC,
      &explicit_user, MAXNAMELEN },

    { "password", o_string, passwd,
      "Password for authenticating us to the peer",
      OPT_PRIO | OPT_STATIC | OPT_HIDE,
      &explicit_passwd, MAXSECRETLEN },

    { "usehostname", o_bool, &usehostname,
      "Must use hostname for authentication", 1 },

    { "remotename", o_string, remote_name,
      "Set remote name for authentication", OPT_PRIO | OPT_STATIC,
      &explicit_remote, MAXNAMELEN },

    { "pap-secrets", o_string, path_upapfile,
      "Set pathname of pap-secrets", OPT_PRIO | OPT_PRIV | OPT_STATIC,
      NULL, MAXPATHLEN },

    { "chap-secrets", o_string, path_chapfile,
      "Set pathname of chap-secrets", OPT_PRIO | OPT_PRIV | OPT_STATIC,
      NULL, MAXPATHLEN },

    { "login", o_bool, &uselogin,
      "Use system password database for PAP", OPT_A2COPY | 1 ,
      &session_mgmt },
    { "enable-session", o_bool, &session_mgmt,
      "Enable session accounting for remote peers", OPT_PRIV | 1 },

    { "papcrypt", o_bool, &cryptpap,
      "PAP passwords are encrypted", 1 },

    { "privgroup", o_special, (void *)privgroup,
      "Allow group members to use privileged options", OPT_PRIV | OPT_A2LIST },

    { "allow-ip", o_special, (void *)set_noauth_addr,
      "Set IP address(es) which can be used without authentication",
      OPT_PRIV | OPT_A2LIST },

    { "remotenumber", o_string, remote_number,
      "Set remote telephone number for authentication", OPT_PRIO | OPT_STATIC,
      NULL, MAXNAMELEN },

    { "allow-number", o_special, (void *)set_permitted_number,
      "Set telephone number(s) which are allowed to connect",
      OPT_PRIV | OPT_A2LIST },

#if defined(PPP_WITH_EAPTLS) || defined(PPP_WITH_PEAP)
    { "ca", o_string, &cacert_file,     "CA certificate in PEM format" },
    { "capath", o_string, &ca_path,     "TLS CA certificate directory" },
    { "crl-dir", o_string, &crl_dir,    "Use CRLs in directory" },
    { "crl", o_string, &crl_file,       "Use specific CRL file" },
    { "max-tls-version", o_string, &max_tls_version,
      "Maximum TLS version (1.0/1.1/1.2 (default)/1.3)" },
    { "tls-verify-key-usage", o_bool, &tls_verify_key_usage,
      "Verify certificate type and extended key usage" },
    { "tls-verify-method", o_string, &tls_verify_method,
      "Verify peer by method (none|subject|name|suffix)" },
#endif

#if defined(PPP_WITH_EAPTLS)
    { "cert", o_string, &cert_file,     "client certificate in PEM format" },
    { "key", o_string, &privkey_file,   "client private key in PEM format" },
    { "pkcs12", o_string, &pkcs12_file, "EAP-TLS client credentials in PKCS12 format" },
    { "need-peer-eap", o_bool, &need_peer_eap,
      "Require the peer to authenticate us", 1 },
#endif /* PPP_WITH_EAPTLS */
    { NULL }
};

const char *
ppp_remote_name()
{
    return remote_name;
}

const char *
ppp_get_remote_number(void)
{
    return remote_number;
}

void
ppp_set_remote_number(const char *buf)
{
    if (buf) {
        strlcpy(remote_number, buf, sizeof(remote_number));
        ppp_script_setenv("REMOTENUMBER", remote_number, 0);
    }
}

const char *
ppp_peer_authname(char *buf, size_t bufsz)
{
    if (buf && bufsz > 0) {
        strlcpy(buf, peer_authname, bufsz);
        return buf;
    }
    return peer_authname;
}

/*
 * setupapfile - specifies UPAP info for authenticating with peer.
 */
static int
setupapfile(char **argv)
{
    FILE *ufile;
    int l;
    uid_t euid;
    char u[MAXNAMELEN], p[MAXSECRETLEN];

    lcp_allowoptions[0].neg_upap = 1;

    if (*argv == NULL)
          novm("+ua file name");

    if (fname != NULL)
          free(fname);
    /* open user info file */
    fname = strdup(*argv);
    if (fname == NULL)
          novm("+ua file name");
    euid = geteuid();
    if (seteuid(getuid()) == -1) {
          ppp_option_error("unable to reset uid before opening %s: %m", fname);
        free(fname);
          return 0;
    }
    ufile = fopen(fname, "r");
    if (seteuid(euid) == -1)
          fatal("unable to regain privileges: %m");
    if (ufile == NULL) {
          ppp_option_error("unable to open user login data file %s", fname);
        free(fname);
          return 0;
    }
    check_access(ufile, fname);

    /* get username */
    if (fgets(u, MAXNAMELEN - 1, ufile) == NULL
          || fgets(p, MAXSECRETLEN - 1, ufile) == NULL) {
          fclose(ufile);
          ppp_option_error("unable to read user login data file %s", fname);
        free(fname);
          return 0;
    }
    fclose(ufile);

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

    if (override_value("user", option_priority, fname)) {
          strlcpy(user, u, sizeof(user));
          explicit_user = 1;
    }
    if (override_value("passwd", option_priority, fname)) {
          strlcpy(passwd, p, sizeof(passwd));
          explicit_passwd = 1;
    }

    free(fname);
    return (1);
}


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

    g = getgrnam(*argv);
    if (g == 0) {
          ppp_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.
 */
static int
set_noauth_addr(char **argv)
{
    char *addr = *argv;
    int l = strlen(addr) + 1;
    struct wordlist *wp;

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


/*
 * set_permitted_number - set remote telephone number(s) that may connect.
 */
static int
set_permitted_number(char **argv)
{
    char *number = *argv;
    int l = strlen(number) + 1;
    struct wordlist *wp;

    wp = (struct wordlist *) malloc(sizeof(struct wordlist) + l);
    if (wp == NULL)
          novm("allow-number argument");
    wp->word = (char *) (wp + 1);
    wp->next = permitted_numbers;
    BCOPY(number, wp->word, l);
    permitted_numbers = wp;
    return 1;
}


/*
 * An Open on LCP has requested a change from Dead to Establish phase.
 */
void
link_required(int unit)
{
}

/*
 * Bring the link up to the point of being able to do ppp.
 */
void start_link(int unit)
{
    ppp_set_status(EXIT_CONNECT_FAILED);
    new_phase(PHASE_SERIALCONN);

    hungup = 0;
    devfd = the_channel->connect();
    if (devfd < 0)
          goto fail;

    /* set up the serial device as a ppp interface */
    /*
     * N.B. we used to do tdb_writelock/tdb_writeunlock around this
     * (from establish_ppp to set_ifunit).  However, we won't be
     * doing the set_ifunit in multilink mode, which is the only time
     * we need the atomicity that the tdb_writelock/tdb_writeunlock
     * gives us.  Thus we don't need the tdb_writelock/tdb_writeunlock.
     */
    fd_ppp = the_channel->establish_ppp(devfd);
    if (fd_ppp < 0) {
          ppp_set_status(EXIT_FATAL_ERROR);
          goto disconnect;
    }

    if (!demand && ifunit >= 0)
          set_ifunit(1);

    /*
     * Start opening the connection and wait for
     * incoming events (reply, timeout, etc.).
     */
    if (ifunit >= 0)
          notice("Connect: %s <--> %s", ifname, ppp_devname);
    else
          notice("Starting negotiation on %s", ppp_devname);
    add_fd(fd_ppp);

    ppp_set_status(EXIT_NEGOTIATION_FAILED);
    new_phase(PHASE_ESTABLISH);

    lcp_lowerup(0);
    return;

 disconnect:
    new_phase(PHASE_DISCONNECT);
    if (the_channel->disconnect)
          the_channel->disconnect();

 fail:
    new_phase(PHASE_DEAD);
    if (the_channel->cleanup)
          (*the_channel->cleanup)();
}

/*
 * LCP has terminated the link; go to the Dead phase and take the
 * physical layer down.
 */
void
link_terminated(int unit)
{
    if (in_phase(PHASE_DEAD) || in_phase(PHASE_MASTER))
          return;
    new_phase(PHASE_DISCONNECT);

    if (pap_logout_hook) {
          pap_logout_hook();
    }
    session_end(devnam);

    if (!mp_on()) {
          notice("Connection terminated.");
          print_link_stats();
    } else
          notice("Link terminated.");

    /*
     * Delete pid files before disestablishing ppp.  Otherwise it
     * can happen that another pppd gets the same unit and then
     * we delete its pid file.
     */
    if (!demand && !mp_on())
          remove_pidfiles();
    /*
     * If we may want to bring the link up again, transfer
     * the ppp unit back to the loopback.  Set the
     * real serial device back to its normal mode of operation.
     */
    if (fd_ppp >= 0) {
          remove_fd(fd_ppp);
          clean_check();
          the_channel->disestablish_ppp(devfd);
          if (mp_on())
              mp_exit_bundle();
          fd_ppp = -1;
    }
    if (!hungup)
          lcp_lowerdown(0);
    if (!mp_on() && !demand)
          ppp_script_unsetenv("IFNAME");

    /*
     * Run disconnector script, if requested.
     * XXX we may not be able to do this if the line has hung up!
     */
    if (devfd >= 0 && the_channel->disconnect) {
          the_channel->disconnect();
          devfd = -1;
    }
    if (the_channel->cleanup)
          (*the_channel->cleanup)();

    if (mp_on() && mp_master()) {
          if (!bundle_terminating) {
              new_phase(PHASE_MASTER);
              if (master_detach && !detached)
                    detach();
          } else
              mp_bundle_terminated();
    } else
          new_phase(PHASE_DEAD);
}

/*
 * LCP has gone down; it will either die or try to re-establish.
 */
void
link_down(int unit)
{
    if (auth_state != s_down) {
          notify(link_down_notifier, 0);
          auth_state = s_down;
          if (auth_script_state == s_up && auth_script_pid == 0) {
              ppp_get_link_stats(NULL);
              auth_script_state = s_down;
              auth_script(PPP_PATH_AUTHDOWN);
          }
    }
    if (!mp_on())
    {
          upper_layers_down(unit);
          if (!in_phase(PHASE_DEAD) && !in_phase(PHASE_MASTER))
              new_phase(PHASE_ESTABLISH);
    }
    /* XXX if doing_multilink, should do something to stop
       network-layer traffic on the link */
}

void upper_layers_down(int unit)
{
    int i;
    struct protent *protp;

    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;
}

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

    /*
     * Tell higher-level protocols that LCP is up.
     */
    if (!mp_on())
          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 && noauth_addrs != NULL)
          set_allowed_addrs(unit, NULL, NULL);

    if (auth_required && !(go->neg_upap || go->neg_chap || go->neg_eap)) {
          /*
           * 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, NULL, NULL);
          } else if (!wo->neg_upap || uselogin || !null_login(unit)) {
              warn("peer refused to authenticate: terminating link");
              ppp_set_status(EXIT_PEER_AUTH_FAILED);
              lcp_close(unit, "peer refused to authenticate");
              return;
          }
    }

#ifdef PPP_WITH_EAPTLS
    if (need_peer_eap && !ao->neg_eap) {
          warn("eap required to authenticate us but no suitable secrets");
          lcp_close(unit, "couldn't negotiate eap");
          ppp_set_status(EXIT_AUTH_TOPEER_FAILED);
          return;
    }

    if (need_peer_eap && !ho->neg_eap) {
          warn("peer doesn't want to authenticate us with eap");
          lcp_close(unit, "couldn't negotiate eap");
          ppp_set_status(EXIT_PEER_AUTH_FAILED);
          return;
    }
#endif

    new_phase(PHASE_AUTHENTICATE);
    auth = 0;
    if (go->neg_eap) {
          eap_authpeer(unit, our_name);
          auth |= EAP_PEER;
    } else if (go->neg_chap) {
          chap_auth_peer(unit, our_name, CHAP_DIGEST(go->chap_mdtype));
          auth |= CHAP_PEER;
    } else if (go->neg_upap) {
          upap_authpeer(unit);
          auth |= PAP_PEER;
    }
    if (ho->neg_eap) {
          eap_authwithpeer(unit, user);
          auth |= EAP_WITHPEER;
    } else if (ho->neg_chap) {
          chap_auth_with_peer(unit, user, CHAP_DIGEST(ho->chap_mdtype));
          auth |= CHAP_WITHPEER;
    } else if (ho->neg_upap) {
          /* If a blank password was explicitly given as an option, trust
             the user and don't try to look up one. */
          if (passwd[0] == 0 && !explicit_passwd) {
              passwd_from_file = 1;
              if (!get_pap_passwd(passwd))
                    error("No secret found for PAP login");
          }
          upap_authwithpeer(unit, user, passwd);
          auth |= PAP_WITHPEER;
    }
    auth_pending[unit] = auth;
    auth_done[unit] = 0;

    if (!auth)
          network_phase(unit);
}

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

    /* Log calling number. */
    if (*remote_number)
          notice("peer from calling number %q authorized", remote_number);

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

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

    /*
     * Process extra options from the secrets file
     */
    if (extra_options) {
          options_from_list(extra_options, 1);
          free_wordlist(extra_options);
          extra_options = 0;
    }
    start_networks(unit);
}

void
start_networks(int unit)
{
    int i;
    struct protent *protp;
    int ecp_required, mppe_required;

    new_phase(PHASE_NETWORK);

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

#ifdef PPP_WITH_FILTER
    if (!demand)
          set_filters(&pass_filter_in, &pass_filter_out,
                        &active_filter_in, &active_filter_out);
#endif
    /* Start CCP and ECP */
    for (i = 0; (protp = protocols[i]) != NULL; ++i)
          if ((protp->protocol == PPP_ECP || protp->protocol == PPP_CCP)
              && protp->enabled_flag && protp->open != NULL)
              (*protp->open)(0);

    /*
     * Bring up other network protocols iff encryption is not required.
     */
    ecp_required = ecp_gotoptions[unit].required;
    mppe_required = ccp_gotoptions[unit].mppe;
    if (!ecp_required && !mppe_required)
          continue_networks(unit);
}

void
continue_networks(int unit)
{
    int i;
    struct protent *protp;

    /*
     * Start the "real" network protocols.
     */
    for (i = 0; (protp = protocols[i]) != NULL; ++i)
          if (protp->protocol < 0xC000
              && protp->protocol != PPP_CCP && protp->protocol != PPP_ECP
              && protp->enabled_flag && protp->open != NULL) {
              (*protp->open)(0);
              ++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'.
 */
void
auth_peer_fail(int unit, int protocol)
{
    /*
     * Authentication failure: take the link down
     */
    ppp_set_status(EXIT_PEER_AUTH_FAILED);
    lcp_close(unit, "Authentication failed");
}

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

    switch (protocol) {
    case PPP_CHAP:
          bit = CHAP_PEER;
          prot = "CHAP";
          switch (prot_flavor) {
          case CHAP_MD5:
              bit |= CHAP_MD5_PEER;
              break;
#ifdef PPP_WITH_CHAPMS
          case CHAP_MICROSOFT:
              bit |= CHAP_MS_PEER;
              break;
          case CHAP_MICROSOFT_V2:
              bit |= CHAP_MS2_PEER;
              break;
#endif
          }
          break;
    case PPP_PAP:
          bit = PAP_PEER;
          prot = "PAP";
          break;
    case PPP_EAP:
          bit = EAP_PEER;
          prot = "EAP";
          break;
    default:
          warn("auth_peer_success: unknown protocol %x", protocol);
          prot = "unknown 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;
    ppp_script_setenv("PEERNAME", peer_authname, 0);
    notice("Peer %q authenticated with %s", peer_authname, prot);

    /* Save the authentication method for later. */
    auth_done[unit] |= bit;

    /*
     * 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'.
 */
void
auth_withpeer_fail(int unit, int 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.
     */
    ppp_set_status(EXIT_AUTH_TOPEER_FAILED);
    lcp_close(unit, "Failed to authenticate ourselves to peer");
}

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

    switch (protocol) {
    case PPP_CHAP:
          bit = CHAP_WITHPEER;
          prot = "CHAP";
          switch (prot_flavor) {
          case CHAP_MD5:
              bit |= CHAP_MD5_WITHPEER;
              break;
#ifdef PPP_WITH_CHAPMS
          case CHAP_MICROSOFT:
              bit |= CHAP_MS_WITHPEER;
              break;
          case CHAP_MICROSOFT_V2:
              bit |= CHAP_MS2_WITHPEER;
              break;
#endif
          }
          break;
    case PPP_PAP:
          if (passwd_from_file)
              BZERO(passwd, MAXSECRETLEN);
          bit = PAP_WITHPEER;
          prot = "PAP";
          break;
    case PPP_EAP:
          bit = EAP_WITHPEER;
          prot = "EAP";
          break;
    default:
          warn("auth_withpeer_success: unknown protocol %x", protocol);
          bit = 0;
    }

    notice("%s authentication succeeded", prot);

    /* Save the authentication method for later. */
    auth_done[unit] |= bit;

    /*
     * 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.
 */
void
np_up(int unit, int proto)
{
    int tlim;

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

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

          /*
           * Set a timeout to close the connection once the maximum
           * connect time has expired.
           */
          if (ppp_get_max_connect_time() > 0)
              TIMEOUT(connect_time_expired, 0, ppp_get_max_connect_time());

          /*
           * Configure a check to see if session has outlived it's limit
           *   in terms of octets
           */
          if (maxoctets > 0)
              TIMEOUT(check_maxoctets, NULL, maxoctets_timeout);

          /*
           * Detach now, if the updetach option was given.
           */
          if (updetach && !nodetach) {
              dbglog("updetach is set. Now detaching.");
              detach();
#ifdef SYSTEMD
          } else if (nodetach && up_sdnotify) {
              dbglog("up_sdnotify is set. Now notifying systemd: READY=1");
              sd_notify(0, "READY=1");
#endif
          }
    }
    ++num_np_up;
}

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

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

/*
 * Periodic callback to check if session has reached its limit. The period defaults
 * to 1 second and is configurable by setting "mo-timeout" in configuration
 */
static void
check_maxoctets(void *arg)
{
    unsigned int used = 0;
    ppp_link_stats_st stats;

    if (ppp_get_link_stats(&stats)) {
        switch(maxoctets_dir) {
            case PPP_OCTETS_DIRECTION_IN:
                used = stats.bytes_in;
                break;
            case PPP_OCTETS_DIRECTION_OUT:
                used = stats.bytes_out;
                break;
            case PPP_OCTETS_DIRECTION_MAXOVERAL:
            case PPP_OCTETS_DIRECTION_MAXSESSION:
                used = (stats.bytes_in > stats.bytes_out)
                                ? stats.bytes_in
                                : stats.bytes_out;
                break;
            default:
                used = stats.bytes_in+stats.bytes_out;
                break;
        }
    }

    if (used > maxoctets) {
          notice("Traffic limit reached. Limit: %u Used: %u", maxoctets, used);
          ppp_set_status(EXIT_TRAFFIC_LIMIT);
          lcp_close(0, "Traffic limit");
          link_stats_print = 0;
          need_holdoff = 0;
    } else {
        TIMEOUT(check_maxoctets, NULL, maxoctets_timeout);
    }
}

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

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

/*
 * connect_time_expired - log a message and close the connection.
 */
static void
connect_time_expired(void *arg)
{
    info("Connect time expired");
    ppp_set_status(EXIT_CONNECT_TIME);
    lcp_close(0, "Connect time expired");         /* Close connection */
    need_holdoff = 0;
}

/*
 * auth_check_options - called to check authentication options.
 */
void
auth_check_options(void)
{
    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)
        strlcpy(our_name, hostname, sizeof(our_name));

    /* If a blank username was explicitly given as an option, trust
       the user and don't use our_name */
    if (user[0] == 0 && !explicit_user)
          strlcpy(user, our_name, sizeof(user));

#if defined(SYSTEM_CA_PATH) && (defined(PPP_WITH_EAPTLS) || defined(PPP_WITH_PEAP))
    /* Use system default for CA Path if not specified */
    if (!ca_path) {
        ca_path = SYSTEM_CA_PATH;
    }
#endif

    /*
     * 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 we selected any CHAP flavors, we should probably negotiate it. :-) */
    if (wo->chap_mdtype)
          wo->neg_chap = 1;

    /* If authentication is required, ask peer for CHAP, PAP, or EAP. */
    if (auth_required) {
          allow_any_ip = 0;
          if (!wo->neg_chap && !wo->neg_upap && !wo->neg_eap) {
              wo->neg_chap = chap_mdtype_all != MDTYPE_NONE;
              wo->chap_mdtype = chap_mdtype_all;
              wo->neg_upap = 1;
              wo->neg_eap = 1;
          }
    } else {
          wo->neg_chap = 0;
          wo->chap_mdtype = MDTYPE_NONE;
          wo->neg_upap = 0;
          wo->neg_eap = 0;
    }

    /*
     * Check whether we have appropriate secrets to use
     * to authenticate the peer.  Note that EAP can authenticate by way
     * of a CHAP-like exchanges as well as SRP.
     */
    lacks_ip = 0;
    can_auth = wo->neg_upap && (uselogin || have_pap_secret(&lacks_ip));
    if (!can_auth && (wo->neg_chap || wo->neg_eap)) {
          can_auth = have_chap_secret((explicit_remote? remote_name: NULL),
                                            our_name, 1, &lacks_ip);
    }
    if (!can_auth && wo->neg_eap) {
          can_auth = have_srp_secret((explicit_remote? remote_name: NULL),
                                            our_name, 1, &lacks_ip);
    }

#ifdef PPP_WITH_EAPTLS
    if (!can_auth && wo->neg_eap) {
          can_auth =
              have_eaptls_secret_server((explicit_remote ? remote_name :
                                               NULL), our_name, 1, &lacks_ip);

    }
#endif

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

          exit(1);
    }

    /*
     * Early check for remote number authorization.
     */
    if (!auth_number()) {
          warn("calling number %q is not authorized", remote_number);
          exit(EXIT_CNID_AUTH_FAILED);
    }
}

/*
 * 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(int unit)
{
    lcp_options *go = &lcp_gotoptions[unit];
    lcp_options *ao = &lcp_allowoptions[unit];
    int hadchap;

    hadchap = -1;
    ao->neg_upap = !refuse_pap && (passwd[0] != 0 || get_pap_passwd(NULL));
    ao->neg_chap = (!refuse_chap || !refuse_mschap || !refuse_mschap_v2)
          && ((passwd[0] != 0 || explicit_passwd) ||
              (hadchap = have_chap_secret(user, (explicit_remote? remote_name:
                                                         NULL), 0, NULL)));
    ao->neg_eap = !refuse_eap && (
          passwd[0] != 0 ||
          (hadchap == 1 || (hadchap == -1 && have_chap_secret(user,
              (explicit_remote? remote_name: NULL), 0, NULL))) ||
          have_srp_secret(user, (explicit_remote? remote_name: NULL), 0, NULL)
#ifdef PPP_WITH_EAPTLS
                    || have_eaptls_secret_client(user, (explicit_remote? remote_name: NULL))
#endif
          );

    hadchap = -1;
    if (go->neg_upap && !uselogin && !have_pap_secret(NULL))
          go->neg_upap = 0;
    if (go->neg_chap) {
          if (!(hadchap = have_chap_secret((explicit_remote? remote_name: NULL),
                                    our_name, 1, NULL)))
              go->neg_chap = 0;
    }
    if (go->neg_eap &&
          (hadchap == 0 || (hadchap == -1 &&
              !have_chap_secret((explicit_remote? remote_name: NULL), our_name,
                    1, NULL))) &&
          !have_srp_secret((explicit_remote? remote_name: NULL), our_name, 1,
              NULL)
#ifdef PPP_WITH_EAPTLS
           && !have_eaptls_secret_server((explicit_remote? remote_name: NULL),
                                           our_name, 1, NULL)
#endif
                    )
          go->neg_eap = 0;
}


/*
 * 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(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.
     */
    slprintf(passwd, sizeof(passwd), "%.*v", passwdlen, apasswd);
    slprintf(user, sizeof(user), "%.*v", userlen, auser);
    *msg = "";

    /*
     * Check if a plugin wants to handle this.
     */
    if (pap_auth_hook) {
          ret = (*pap_auth_hook)(user, passwd, msg, &addrs, &opts);
          if (ret >= 0) {
              /* note: set_allowed_addrs() saves opts (but not addrs):
                 don't free it! */
              if (ret)
                    set_allowed_addrs(unit, addrs, opts);
              else if (opts != 0)
                    free_wordlist(opts);
              if (addrs != 0)
                    free_wordlist(addrs);
              BZERO(passwd, sizeof(passwd));
              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) < 0) {
              warn("no PAP secret found for %s", user);
          } else {
              /*
               * If the secret is "@login", it means to check
               * the password against the login database.
               */
              int login_secret = strcmp(secret, "@login") == 0;
              ret = UPAP_AUTHACK;
              if (uselogin || login_secret) {
                    /* login option or secret is @login */
                    if (session_full(user, passwd, devnam, msg) == 0) {
                        ret = UPAP_AUTHNAK;
                    }
              } else if (session_mgmt) {
                    if (session_check(user, NULL, devnam, NULL) == 0) {
                        warn("Peer %q failed PAP Session verification", user);
                        ret = UPAP_AUTHNAK;
                    }
              }
              if (secret[0] != 0 && !login_secret) {
                    /* password given in pap-secrets - must match */
                    if (cryptpap || strcmp(passwd, secret) != 0) {
#ifdef HAVE_CRYPT_H
                        char *cbuf = crypt(passwd, secret);
                        if (!cbuf || strcmp(cbuf, secret) != 0)
#endif
                              ret = UPAP_AUTHNAK;
                    }
              }
          }
          fclose(f);
    }

    if (ret == UPAP_AUTHNAK) {
        if (**msg == 0)
              *msg = "Login incorrect";
          /*
           * XXX can we ever get here more than once??
           * 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)
              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;
}

/*
 * 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(int unit)
{
    char *filename;
    FILE *f;
    int i, ret;
    struct wordlist *addrs, *opts;
    char secret[MAXWORDLEN];

    /*
     * Check if a plugin wants to handle this.
     */
    ret = -1;
    if (null_auth_hook)
          ret = (*null_auth_hook)(&addrs, &opts);

    /*
     * Open the file of pap secrets and scan for a suitable secret.
     */
    if (ret <= 0) {
          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, 0);
          ret = i >= 0 && secret[0] == 0;
          BZERO(secret, sizeof(secret));
          fclose(f);
    }

    if (ret)
          set_allowed_addrs(unit, addrs, opts);
    else if (opts != 0)
          free_wordlist(opts);
    if (addrs != 0)
          free_wordlist(addrs);

    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(char *passwd)
{
    char *filename;
    FILE *f;
    int ret;
    char secret[MAXWORDLEN];

    /*
     * Check whether a plugin wants to supply this.
     */
    if (pap_passwd_hook) {
          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]? remote_name: NULL),
                              secret, NULL, NULL, filename, 0);
    fclose(f);
    if (ret < 0)
          return 0;
    if (passwd != NULL)
          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(int *lacks_ipp)
{
    FILE *f;
    int ret;
    char *filename;
    struct wordlist *addrs;

    /* let the plugin decide, if there is one */
    if (pap_check_hook) {
          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, 0);
    fclose(f);
    if (ret >= 0 && !some_ip_ok(addrs)) {
          if (lacks_ipp != 0)
              *lacks_ipp = 1;
          ret = -1;
    }
    if (addrs != 0)
          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 can be the null string, meaning we don't
 * know the identity yet.
 */
static int
have_chap_secret(char *client, char *server,
                     int need_ip, int *lacks_ipp)
{
    FILE *f;
    int ret;
    char *filename;
    struct wordlist *addrs;

    if (chap_check_hook) {
          ret = (*chap_check_hook)();
          if (ret >= 0) {
              return ret;
          }
    }

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

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

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

    return ret >= 0;
}


/*
 * have_srp_secret - check whether we have a SRP 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_srp_secret(char *client, char *server, int need_ip, int *lacks_ipp)
{
    FILE *f;
    int ret;
    char *filename;
    struct wordlist *addrs;

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

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

    ret = scan_authfile(f, client, server, NULL, &addrs, NULL, filename, 0);
    fclose(f);
    if (ret >= 0 && need_ip && !some_ip_ok(addrs)) {
          if (lacks_ipp != 0)
              *lacks_ipp = 1;
          ret = -1;
    }
    if (addrs != 0)
          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.
 * (We could be either client or server).
 */
int
get_secret(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];

    if (!am_server && passwd[0] != 0) {
          strlcpy(secbuf, passwd, sizeof(secbuf));
    } else if (!am_server && chap_passwd_hook) {
          if ( (*chap_passwd_hook)(client, secbuf) < 0) {
              error("Unable to obtain CHAP password for %s on %s from plugin",
                      client, server);
              return 0;
          }
    } 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, 0);
          fclose(f);
          if (ret < 0)
              return 0;

          if (am_server)
              set_allowed_addrs(unit, addrs, opts);
          else if (opts != 0)
              free_wordlist(opts);
          if (addrs != 0)
              free_wordlist(addrs);
    }

    len = strlen(secbuf);
    if (len > MAXSECRETLEN) {
          error("Secret for %s on %s is too long", client, server);
          len = MAXSECRETLEN;
    }
    BCOPY(secbuf, secret, len);
    BZERO(secbuf, sizeof(secbuf));
    *secret_len = len;

    return 1;
}


/*
 * get_srp_secret - open the SRP secret file and return the secret
 * for authenticating the given client on the given server.
 * (We could be either client or server).
 */
int
get_srp_secret(int unit, char *client, char *server,
                 char *secret, int am_server)
{
    FILE *fp;
    int ret;
    char *filename;
    struct wordlist *addrs, *opts;

    if (!am_server && passwd[0] != '\0') {
          strlcpy(secret, passwd, MAXWORDLEN);
    } else {
          filename = PPP_PATH_SRPFILE;
          addrs = NULL;

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

          secret[0] = '\0';
          ret = scan_authfile(fp, client, server, secret, &addrs, &opts,
              filename, am_server);
          fclose(fp);
          if (ret < 0)
              return 0;

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

    return 1;
}

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

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

    /*
     * Count the number of IP addresses given.
     */
    n = wordlist_count(addrs) + wordlist_count(noauth_addrs);
    if (n == 0)
          return;
    ip = (struct permitted_ip *) malloc((n + 1) * sizeof(struct permitted_ip));
    if (ip == 0)
          return;

    /* temporarily append the noauth_addrs list to addrs */
    for (plink = &addrs; *plink != NULL; plink = &(*plink)->next)
          ;
    *plink = noauth_addrs;

    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 auth. 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;
          }

          hp = gethostbyname(ptr_word);
          if (hp != NULL && hp->h_addrtype == AF_INET) {
              a = *(u_int32_t *)hp->h_addr;
          } else {
              np = getnetbyname (ptr_word);
              if (np != NULL && np->n_addrtype == AF_INET) {
                    a = htonl ((u_int32_t)np->n_net);
                    if (ptr_mask == NULL) {
                        /* calculate appropriate mask for net */
                        ah = ntohl(a);
                        if (IN_CLASSA(ah))
                              mask = IN_CLASSA_NET;
                        else if (IN_CLASSB(ah))
                              mask = IN_CLASSB_NET;
                        else if (IN_CLASSC(ah))
                              mask = IN_CLASSC_NET;
                    }
              } else {
                    a = inet_addr (ptr_word);
              }
          }

          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;
    }
    *plink = NULL;

    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;
          /*
           * Do we insist on this address?  No, if there are other
           * addresses authorized than the suggested one.
           */
          if (n > 1)
              wo->accept_remote = 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(int unit, u_int32_t addr)
{
    int ok;

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

    if (allowed_address_hook) {
          ok = allowed_address_hook(addr);
          if (ok >= 0) return ok;
    }

    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(u_int32_t addr, struct permitted_ip *addrs)
{
    for (; ; ++addrs)
          if ((addr & addrs->mask) == addrs->base)
              return addrs->permit;
}

/*
 * Check if given addr in network byte order is in the looback network, or a multicast address.
 */
bool
ppp_bad_ip_addr(u_int32_t addr)
{
    addr = ntohl(addr);
    return (addr >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET
          || IN_MULTICAST(addr) || IN_BADCLASS(addr);
}

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

/*
 * auth_number - check whether the remote number is allowed to connect.
 * Returns 1 if authorized, 0 otherwise.
 */
int
auth_number(void)
{
    struct wordlist *wp = permitted_numbers;
    size_t l;

    /* Allow all if no authorization list. */
    if (!wp)
          return 1;

    /* Allow if we have a match in the authorization list. */
    while (wp) {
          /* trailing '*' wildcard */
          l = strlen(wp->word);
          if (l > 0 && (wp->word)[l - 1] == '*') {
              if (!strncasecmp(wp->word, remote_number, l - 1))
                    return 1;
          } else if (strcasecmp(wp->word, remote_number) == 0)
              return 1;
          wp = wp->next;
    }

    return 0;
}

/*
 * check_access - complain if a secret file has too-liberal permissions.
 */
static void
check_access(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.
 * We assume secret is NULL or points to MAXWORDLEN bytes of space.
 * Flags are non-zero if we need two colons in the secret in order to
 * match.
 */
static int
scan_authfile(FILE *f, char *client, char *server,
                char *secret, struct wordlist **addrs,
                struct wordlist **opts, char *filename,
                int flags)
{
    int newline, xxx;
    int got_flag, best_flag;
    FILE *sf;
    struct wordlist *ap, *addr_list, *alist, **app;
    char word[MAXWORDLEN];
    char atfile[MAXWORDLEN];
    char lsecret[MAXWORDLEN];
    char *cp;

    if (addrs != NULL)
          *addrs = NULL;
    if (opts != NULL)
          *opts = 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 (!ISWILD(word)) {
              if (server != NULL && strcmp(word, server) != 0)
                    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;

          /*
           * SRP-SHA1 authenticator should never be reading secrets from
           * a file.  (Authenticatee may, though.)
           */
          if (flags && ((cp = strchr(word, ':')) == NULL ||
              strchr(cp + 1, ':') == NULL))
              continue;

          if (secret != NULL) {
              /*
               * Special syntax: @/pathname means read secret from file.
               */
              if (word[0] == '@' && word[1] == '/') {
                    strlcpy(atfile, word+1, sizeof(atfile));
                    if ((sf = fopen(atfile, "r")) == NULL) {
                        warn("can't open indirect secret file %s", atfile);
                        continue;
                    }
                    check_access(sf, atfile);
                    if (!getword(sf, word, &xxx, atfile)) {
                        warn("no secret in indirect secret file %s", atfile);
                        fclose(sf);
                        continue;
                    }
                    fclose(sf);
              }
              strlcpy(lsecret, word, sizeof(lsecret));
          }

          /*
           * Now read address authorization info and make a wordlist.
           */
          app = &alist;
          for (;;) {
              size_t len;
              if (!getword(f, word, &newline, filename) || newline)
                    break;
              len = strlen(word) + 1;
              ap = (struct wordlist *)malloc(sizeof(struct wordlist) + len);
              if (ap == NULL)
                    novm("authorized addresses");
              ap->word = (char *) (ap + 1);
              memcpy(ap->word, word, len);
              *app = ap;
              app = &ap->next;
          }
          *app = NULL;

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

          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;
}

/*
 * wordlist_count - return the number of items in a wordlist
 */
static int
wordlist_count(struct wordlist *wp)
{
    int n;

    for (n = 0; wp != NULL; wp = wp->next)
          ++n;
    return n;
}

/*
 * free_wordlist - release memory allocated for a wordlist.
 */
static void
free_wordlist(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.
 */
static void
auth_script_done(void *arg)
{
    auth_script_pid = 0;
    switch (auth_script_state) {
    case s_up:
          if (auth_state == s_down) {
              auth_script_state = s_down;
              auth_script(PPP_PATH_AUTHDOWN);
          }
          break;
    case s_down:
          if (auth_state == s_up) {
              auth_script_state = s_up;
              auth_script(PPP_PATH_AUTHUP);
          }
          break;
    }
}

/*
 * auth_script - execute a script with arguments
 * interface-name peer-name real-user tty speed
 */
static void
auth_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 {
          slprintf(struid, sizeof(struid), "%d", getuid());
          user_name = struid;
    }
    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] = ipparam;
    argv[7] = NULL;

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


#ifdef PPP_WITH_EAPTLS
static int
have_eaptls_secret_server(char *client, char *server,
                                int need_ip, int *lacks_ipp)
{
    FILE *f;
    int ret;
    char *filename;
    struct wordlist *addrs;
    char servcertfile[MAXWORDLEN];
    char clicertfile[MAXWORDLEN];
    char cacertfile[MAXWORDLEN];
    char pkfile[MAXWORDLEN];

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

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

    ret =
          scan_authfile_eaptls(f, client, server, clicertfile, servcertfile,
                                   cacertfile, pkfile, &addrs, NULL, filename,
                                   0);

    fclose(f);

/*
    if (ret >= 0 && !eaptls_init_ssl(1, cacertfile, servcertfile,
                                        clicertfile, pkfile))
                    ret = -1;
*/

          if (ret >= 0 && need_ip && !some_ip_ok(addrs)) {
                    if (lacks_ipp != 0)
                              *lacks_ipp = 1;
                    ret = -1;
    }
    if (addrs != 0)
                    free_wordlist(addrs);

    return ret >= 0;
}


static int
have_eaptls_secret_client(char *client, char *server)
{
    FILE *f;
    int ret;
    char *filename;
    struct wordlist *addrs = NULL;
    char servcertfile[MAXWORDLEN];
    char clicertfile[MAXWORDLEN];
    char cacertfile[MAXWORDLEN];
    char pkfile[MAXWORDLEN];

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

          if ((cacert_file || ca_path) && cert_file && privkey_file)
                    return 1;
          if (pkcs12_file)
                    return 1;

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

    ret =
          scan_authfile_eaptls(f, client, server, clicertfile, servcertfile,
                                   cacertfile, pkfile, &addrs, NULL, filename,
                                   0);
    fclose(f);

/*
    if (ret >= 0 && !eaptls_init_ssl(0, cacertfile, clicertfile,
                                        servcertfile, pkfile))
                    ret = -1;
*/

    if (addrs != 0)
                    free_wordlist(addrs);

    return ret >= 0;
}


static int
scan_authfile_eaptls(FILE *f, char *client, char *server,
                         char *cli_cert, char *serv_cert, char *ca_cert,
                         char *pk, struct wordlist **addrs,
                         struct wordlist **opts,
                         char *filename, int flags)
{
    int newline;
    int got_flag, best_flag;
    struct wordlist *ap, *addr_list, *alist, **app;
    char word[MAXWORDLEN];

    if (addrs != NULL)
          *addrs = NULL;
    if (opts != NULL)
          *opts = 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 (!ISWILD(word)) {
              if (server != NULL && strcmp(word, server) != 0)
                    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 cli_cert
           */
          if (!getword(f, word, &newline, filename))
              break;
          if (newline)
              continue;
          if (strcmp(word, "-") != 0) {
              strlcpy(cli_cert, word, MAXWORDLEN);
          } else
              cli_cert[0] = 0;

          /*
           * Get serv_cert
           */
          if (!getword(f, word, &newline, filename))
              break;
          if (newline)
              continue;
          if (strcmp(word, "-") != 0) {
              strlcpy(serv_cert, word, MAXWORDLEN);
          } else
              serv_cert[0] = 0;

          /*
           * Get ca_cert
           */
          if (!getword(f, word, &newline, filename))
              break;
          if (newline)
              continue;
          strlcpy(ca_cert, word, MAXWORDLEN);

          /*
           * Get pk
           */
          if (!getword(f, word, &newline, filename))
              break;
          if (newline)
              continue;
          strlcpy(pk, word, MAXWORDLEN);


          /*
           * 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) + strlen(word) + 1);
              if (ap == NULL)
                    novm("authorized addresses");
              ap->word = (char *) (ap + 1);
              strcpy(ap->word, word);
              *app = ap;
              app = &ap->next;
          }
          *app = NULL;
          /*
           * This is the best so far; remember it.
           */
          best_flag = got_flag;
          if (addr_list)
              free_wordlist(addr_list);
          addr_list = alist;

          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;
}


int
get_eaptls_secret(int unit, char *client, char *server,
                      char *clicertfile, char *servcertfile, char *cacertfile,
                      char *capath, char *pkfile, char *pkcs12, int am_server)
{
    FILE *fp;
    int ret;
    char *filename         = NULL;
    struct wordlist *addrs = NULL;
    struct wordlist *opts  = NULL;

          /* maybe overkill, but it eases debugging */
          bzero(clicertfile, MAXWORDLEN);
          bzero(servcertfile, MAXWORDLEN);
          bzero(cacertfile, MAXWORDLEN);
          bzero(capath, MAXWORDLEN);
          bzero(pkfile, MAXWORDLEN);
          bzero(pkcs12, MAXWORDLEN);

          /* the ca+cert+privkey can also be specified as options */
          if (!am_server && (cacert_file || ca_path) && cert_file && privkey_file )
          {
                    strlcpy( clicertfile, cert_file, MAXWORDLEN );
                    if (cacert_file)
                              strlcpy( cacertfile, cacert_file, MAXWORDLEN );
                    if (ca_path)
                              strlcpy( capath, ca_path, MAXWORDLEN );
                    strlcpy( pkfile, privkey_file, MAXWORDLEN );
          }
    else if (!am_server && pkcs12_file)
          {
                    strlcpy( pkcs12, pkcs12_file, MAXWORDLEN );
                    if (cacert_file)
                              strlcpy( cacertfile, cacert_file, MAXWORDLEN );
                    if (ca_path)
                              strlcpy( capath, ca_path, MAXWORDLEN );
          }
          else
          {
                    filename = (am_server ? PPP_PATH_EAPTLSSERVFILE : PPP_PATH_EAPTLSCLIFILE);
                    addrs = NULL;

                    fp = fopen(filename, "r");
                    if (fp == NULL)
                    {
                              error("Can't open eap-tls secret file %s: %m", filename);
                              return 0;
                    }

                    check_access(fp, filename);

                    ret = scan_authfile_eaptls(fp, client, server, clicertfile, servcertfile,
                                        cacertfile, pkfile, &addrs, &opts, filename, 0);

                    fclose(fp);

                    if (ret < 0) return 0;
          }

    if (eaptls_passwd_hook)
    {
                    dbglog( "Calling eaptls password hook" );
                    if ( (*eaptls_passwd_hook)(pkfile, passwd) < 0)
                    {
                               error("Unable to obtain EAP-TLS password for %s (%s) from plugin",
                                        client, pkfile);
                        return 0;
                    }
          }
    if (am_server)
                    set_allowed_addrs(unit, addrs, opts);
    else if (opts != NULL)
                    free_wordlist(opts);
    if (addrs != NULL)
                    free_wordlist(addrs);

    return 1;
}
#endif