auth.c

经典的ppp程序

	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_upap) {
	auth_state = s_up;
	if (auth_script_state == s_down && auth_script_pid == 0) {
	    auth_script_state = s_up;
	    auth_script(_PATH_AUTHUP);
	}
    }

#ifdef CBCP_SUPPORT
    /*
     * 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();
}

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 */

#ifdef PPP_FILTER
    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'.
 */
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'.
 */
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.
 */
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;
	new_phase(PHASE_RUNNING);

	if (idle_time_hook != 0)
	    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, 0, maxconnect);

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

/*
 * np_down - a network protocol has gone down.
 */
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.
 */
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.
 */
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 != 0) {
	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.
 */
static void
connect_time_expired(arg)
    void *arg;
{
    info("Connect time expired");
    lcp_close(0, "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)
	strlcpy(our_name, hostname, sizeof(our_name));
    if (user[0] == 0)
	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) {
	allow_any_ip = 0;
	if (!wo->neg_chap && !wo->neg_upap) {
	    wo->neg_chap = 1;
	    wo->neg_upap = 1;
	}
    } else {
	wo->neg_chap = 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) {
	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[0];

    ao->neg_upap = !refuse_pap && (passwd[0] != 0 || get_pap_passwd(NULL));
    ao->neg_chap = !refuse_chap
	&& (passwd[0] != 0
	    || have_chap_secret(user, (explicit_remote? remote_name: NULL),
				0, NULL));

    if (go->neg_upap && !uselogin && !have_pap_secret(NULL))
	go->neg_upap = 0;
    if (go->neg_chap) {
	if (!have_chap_secret((explicit_remote? remote_name: NULL),
			      our_name, 1, NULL))
	    go->neg_chap = 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(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.
     */
    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) {
	    if (ret)
		set_allowed_addrs(unit, addrs, opts);
	    BZERO(passwd, sizeof(passwd));
	    if (addrs != 0)
		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);
	} 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 */
		ret = plogin(user, passwd, msg);
		if (ret == UPAP_AUTHNAK)
		    warn("PAP login failure for %s", user);
		else
		    used_login = 1;
	    }
	    if (secret[0] != 0 && !login_secret) {
		/* password given in pap-secrets - must match */
		if ((cryptpap || strcmp(passwd, secret) != 0)
		    && strcmp(crypt(passwd, secret), secret) != 0) {
		    ret = UPAP_AUTHNAK;
		    warn("PAP authentication failure for %s", user);
		}
	    }
	}