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+/*
+ * auth.c - PPP authentication and phase control.
+ *
+ * Copyright (c) 1993 The Australian National University.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by the Australian National University. The name of the University
+ * may not be used to endorse or promote products derived from this
+ * software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * Copyright (c) 1989 Carnegie Mellon University.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by Carnegie Mellon University. The name of the
+ * University may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+#define RCSID "$Id$"
+
+#include <stdio.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <pwd.h>
+#include <grp.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/socket.h>
+#include <utmp.h>
+#include <fcntl.h>
+#if defined(_PATH_LASTLOG) && defined(_linux_)
+#include <lastlog.h>
+#endif
+
+#include <netdb.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#ifdef USE_PAM
+#include <security/pam_appl.h>
+#endif
+
+#ifdef HAS_SHADOW
+#include <shadow.h>
+#ifndef PW_PPP
+#define PW_PPP PW_LOGIN
+#endif
+#endif
+
+#include "pppd.h"
+#include "fsm.h"
+#include "lcp.h"
+#include "ipcp.h"
+#include "upap.h"
+#include "chap.h"
+#ifdef CBCP_SUPPORT
+#include "cbcp.h"
+#endif
+#include "pathnames.h"
+
+static const char rcsid[] = RCSID;
+
+/* Bits in scan_authfile return value */
+#define NONWILD_SERVER 1
+#define NONWILD_CLIENT 2
+
+#define ISWILD(word) (word[0] == '*' && word[1] == 0)
+
+/* The name by which the peer authenticated itself to us. */
+char peer_authname[MAXNAMELEN];
+
+/* Records which authentication operations haven't completed yet. */
+static int auth_pending[NUM_PPP];
+
+/* Set if we have successfully called plogin() */
+static int logged_in;
+
+/* List of addresses which the peer may use. */
+static struct permitted_ip *addresses[NUM_PPP];
+
+/* Wordlist giving addresses which the peer may use
+ without authenticating itself. */
+static struct wordlist *noauth_addrs;
+
+/* Extra options to apply, from the secrets file entry for the peer. */
+static struct wordlist *extra_options;
+
+/* Number of network protocols which we have opened. */
+static int num_np_open;
+
+/* Number of network protocols which have come up. */
+static int num_np_up;
+
+/* Set if we got the contents of passwd[] from the pap-secrets file. */
+static int passwd_from_file;
+
+/* Set if we require authentication only because we have a default route. */
+static bool default_auth;
+
+/* Hook to enable a plugin to control the idle time limit */
+int (*idle_time_hook) __P((struct ppp_idle *)) = NULL;
+
+/* Hook for a plugin to say whether we can possibly authenticate any peer */
+int (*pap_check_hook) __P((void)) = NULL;
+
+/* Hook for a plugin to check the PAP user and password */
+int (*pap_auth_hook) __P((char *user, char *passwd, char **msgp,
+ struct wordlist **paddrs,
+ struct wordlist **popts)) = NULL;
+
+/* Hook for a plugin to know about the PAP user logout */
+void (*pap_logout_hook) __P((void)) = NULL;
+
+/* Hook for a plugin to get the PAP password for authenticating us */
+int (*pap_passwd_hook) __P((char *user, char *passwd)) = NULL;
+
+/*
+ * This is used to ensure that we don't start an auth-up/down
+ * script while one is already running.
+ */
+enum script_state {
+ s_down,
+ s_up
+};
+
+static enum script_state auth_state = s_down;
+static enum script_state auth_script_state = s_down;
+static pid_t auth_script_pid = 0;
+
+static int used_login; /* peer authenticated against login database */
+
+/*
+ * Option variables.
+ */
+bool uselogin = 0; /* Use /etc/passwd for checking PAP */
+bool cryptpap = 0; /* Passwords in pap-secrets are encrypted */
+bool refuse_pap = 0; /* Don't wanna auth. ourselves with PAP */
+bool refuse_chap = 0; /* Don't wanna auth. ourselves with CHAP */
+bool usehostname = 0; /* Use hostname for our_name */
+bool auth_required = 0; /* Always require authentication from peer */
+bool allow_any_ip = 0; /* Allow peer to use any IP address */
+bool explicit_remote = 0; /* User specified explicit remote name */
+char remote_name[MAXNAMELEN]; /* Peer's name for authentication */
+
+static char *uafname; /* name of most recent +ua file */
+
+/* Bits in auth_pending[] */
+#define PAP_WITHPEER 1
+#define PAP_PEER 2
+#define CHAP_WITHPEER 4
+#define CHAP_PEER 8
+
+extern char *crypt __P((const char *, const char *));
+
+/* Prototypes for procedures local to this file. */
+
+static void network_phase __P((int));
+static void check_idle __P((void *));
+static void connect_time_expired __P((void *));
+static int plogin __P((char *, char *, char **));
+static void plogout __P((void));
+static int null_login __P((int));
+static int get_pap_passwd __P((char *));
+static int have_pap_secret __P((int *));
+static int have_chap_secret __P((char *, char *, int, int *));
+static int ip_addr_check __P((u_int32_t, struct permitted_ip *));
+static int scan_authfile __P((FILE *, char *, char *, char *,
+ struct wordlist **, struct wordlist **,
+ char *));
+static void free_wordlist __P((struct wordlist *));
+static void auth_script __P((char *));
+static void auth_script_done __P((void *));
+static void set_allowed_addrs __P((int, struct wordlist *, struct wordlist *));
+static int some_ip_ok __P((struct wordlist *));
+static int setupapfile __P((char **));
+static int privgroup __P((char **));
+static int set_noauth_addr __P((char **));
+static void check_access __P((FILE *, char *));
+static int wordlist_count __P((struct wordlist *));
+
+/*
+ * Authentication-related options.
+ */
+option_t 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, &lcp_wantoptions[0].neg_chap,
+ "Require CHAP authentication from peer",
+ OPT_PRIOSUB | 1, &auth_required },
+ { "+chap", o_bool, &lcp_wantoptions[0].neg_chap,
+ "Require CHAP authentication from peer",
+ OPT_ALIAS | OPT_PRIOSUB | 1, &auth_required },
+
+ { "refuse-pap", o_bool, &refuse_pap,
+ "Don't agree to auth to peer with PAP", 1 },
+ { "-pap", o_bool, &refuse_pap,
+ "Don't allow PAP authentication with peer", OPT_ALIAS | 1 },
+
+ { "refuse-chap", o_bool, &refuse_chap,
+ "Don't agree to auth to peer with CHAP", 1 },
+ { "-chap", o_bool, &refuse_chap,
+ "Don't allow CHAP authentication with peer", OPT_ALIAS | 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, &uafname },
+
+ { "user", o_string, user,
+ "Set name for auth with peer", OPT_PRIO | OPT_STATIC, NULL, MAXNAMELEN },
+
+ { "password", o_string, passwd,
+ "Password for authenticating us to the peer",
+ OPT_PRIO | OPT_STATIC | OPT_HIDE, NULL, 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 },
+
+ { "login", o_bool, &uselogin,
+ "Use system password database for PAP", 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 },
+
+ { NULL }
+};
+
+/*
+ * setupapfile - specifies UPAP info for authenticating with peer.
+ */
+static int
+setupapfile(argv)
+ char **argv;
+{
+ FILE *ufile;
+ int l;
+ char u[MAXNAMELEN], p[MAXSECRETLEN];
+ char *fname;
+
+ lcp_allowoptions[0].neg_upap = 1;
+
+ /* open user info file */
+ fname = strdup(*argv);
+ if (fname == NULL)
+ novm("+ua file name");
+ seteuid(getuid());
+ ufile = fopen(fname, "r");
+ seteuid(0);
+ if (ufile == NULL) {
+ option_error("unable to open user login data file %s", fname);
+ return 0;
+ }
+ check_access(ufile, fname);
+ uafname = fname;
+
+ /* get username */
+ if (fgets(u, MAXNAMELEN - 1, ufile) == NULL
+ || fgets(p, MAXSECRETLEN - 1, ufile) == NULL){
+ option_error("unable to read user login data file %s", 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));
+ if (override_value("passwd", option_priority, fname))
+ strlcpy(passwd, p, sizeof(passwd));
+
+ return (1);
+}
+
+
+/*
+ * privgroup - allow members of the group to have privileged access.
+ */
+static int
+privgroup(argv)
+ char **argv;
+{
+ struct group *g;
+ int i;
+
+ g = getgrnam(*argv);
+ if (g == 0) {
+ 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(argv)
+ 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;
+}
+
+
+/*
+ * An Open on LCP has requested a change from Dead to Establish phase.
+ * Do what's necessary to bring the physical layer up.
+ */
+void
+link_required(unit)
+ int unit;
+{
+}
+
+/*
+ * LCP has terminated the link; go to the Dead phase and take the
+ * physical layer down.
+ */
+void
+link_terminated(unit)
+ int unit;
+{
+ if (phase == PHASE_DEAD)
+ return;
+ if (pap_logout_hook) {
+ pap_logout_hook();
+ } else {
+ if (logged_in)
+ plogout();
+ }
+ new_phase(PHASE_DEAD);
+ notice("Connection terminated.");
+}
+
+/*
+ * LCP has gone down; it will either die or try to re-establish.
+ */
+void
+link_down(unit)
+ int unit;
+{
+ int i;
+ struct protent *protp;
+
+ auth_state = s_down;
+ if (auth_script_state == s_up && auth_script_pid == 0) {
+ update_link_stats(unit);
+ auth_script_state = s_down;
+ auth_script(_PATH_AUTHDOWN);
+ }
+ for (i = 0; (protp = protocols[i]) != NULL; ++i) {
+ if (!protp->enabled_flag)
+ continue;
+ if (protp->protocol != PPP_LCP && protp->lowerdown != NULL)
+ (*protp->lowerdown)(unit);
+ if (protp->protocol < 0xC000 && protp->close != NULL)
+ (*protp->close)(unit, "LCP down");
+ }
+ num_np_open = 0;
+ num_np_up = 0;
+ if (phase != PHASE_DEAD)
+ new_phase(PHASE_TERMINATE);
+}
+
+/*
+ * The link is established.
+ * Proceed to the Dead, Authenticate or Network phase as appropriate.
+ */
+void
+link_established(unit)
+ int unit;
+{
+ int auth;
+ lcp_options *wo = &lcp_wantoptions[unit];
+ lcp_options *go = &lcp_gotoptions[unit];
+ lcp_options *ho = &lcp_hisoptions[unit];
+ int i;
+ struct protent *protp;
+
+ /*
+ * Tell higher-level protocols that LCP is up.
+ */
+ for (i = 0; (protp = protocols[i]) != NULL; ++i)
+ if (protp->protocol != PPP_LCP && protp->enabled_flag
+ && protp->lowerup != NULL)
+ (*protp->lowerup)(unit);
+
+ if (auth_required && !(go->neg_chap || go->neg_upap)) {
+ /*
+ * We wanted the peer to authenticate itself, and it refused:
+ * if we have some address(es) it can use without auth, fine,
+ * otherwise treat it as though it authenticated with PAP using
+ * a username * of "" and a password of "". If that's not OK,
+ * boot it out.
+ */
+ if (noauth_addrs != NULL) {
+ set_allowed_addrs(unit, NULL, NULL);
+ } else if (!wo->neg_upap || uselogin || !null_login(unit)) {
+ warn("peer refused to authenticate: terminating link");
+ lcp_close(unit, "peer refused to authenticate");
+ status = EXIT_PEER_AUTH_FAILED;
+ return;
+ }
+ }
+
+ new_phase(PHASE_AUTHENTICATE);
+ used_login = 0;
+ auth = 0;
+ if (go->neg_chap) {
+ ChapAuthPeer(unit, our_name, go->chap_mdtype);
+ auth |= CHAP_PEER;
+ } else if (go->neg_upap) {
+ upap_authpeer(unit);
+ auth |= PAP_PEER;
+ }
+ if (ho->neg_chap) {
+ ChapAuthWithPeer(unit, user, ho->chap_mdtype);
+ auth |= CHAP_WITHPEER;
+ } else if (ho->neg_upap) {
+ if (passwd[0] == 0) {
+ passwd_from_file = 1;
+ if (!get_pap_passwd(passwd))
+ error("No secret found for PAP login");
+ }
+ 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);
+ }
+ }
+ }
+ 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;
+}
+
+/*
+ * This function is needed for PAM.
+ */
+
+#ifdef USE_PAM
+/* Static variables used to communicate between the conversation function
+ * and the server_login function
+ */
+static char *PAM_username;
+static char *PAM_password;
+static int PAM_error = 0;
+static pam_handle_t *pamh = NULL;
+
+/* PAM conversation function
+ * Here we assume (for now, at least) that echo on means login name, and
+ * echo off means password.
+ */
+
+static int PAM_conv (int num_msg, const struct pam_message **msg,
+ struct pam_response **resp, void *appdata_ptr)
+{
+ int replies = 0;
+ struct pam_response *reply = NULL;
+
+#define COPY_STRING(s) (s) ? strdup(s) : NULL
+
+ reply = malloc(sizeof(struct pam_response) * num_msg);
+ if (!reply) return PAM_CONV_ERR;
+
+ for (replies = 0; replies < num_msg; replies++) {
+ switch (msg[replies]->msg_style) {
+ case PAM_PROMPT_ECHO_ON:
+ reply[replies].resp_retcode = PAM_SUCCESS;
+ reply[replies].resp = COPY_STRING(PAM_username);
+ /* PAM frees resp */
+ break;
+ case PAM_PROMPT_ECHO_OFF:
+ reply[replies].resp_retcode = PAM_SUCCESS;
+ reply[replies].resp = COPY_STRING(PAM_password);
+ /* PAM frees resp */
+ break;
+ case PAM_TEXT_INFO:
+ /* fall through */
+ case PAM_ERROR_MSG:
+ /* ignore it, but pam still wants a NULL response... */
+ reply[replies].resp_retcode = PAM_SUCCESS;
+ reply[replies].resp = NULL;
+ break;
+ default:
+ /* Must be an error of some sort... */
+ free (reply);
+ PAM_error = 1;
+ return PAM_CONV_ERR;
+ }
+ }
+ *resp = reply;
+ return PAM_SUCCESS;
+}
+
+static struct pam_conv PAM_conversation = {
+ &PAM_conv,
+ NULL
+};
+#endif /* USE_PAM */
+
+/*
+ * plogin - Check the user name and password against the system
+ * password database, and login the user if OK.
+ *
+ * returns:
+ * UPAP_AUTHNAK: Login failed.
+ * UPAP_AUTHACK: Login succeeded.
+ * In either case, msg points to an appropriate message.
+ */
+
+static int
+plogin(user, passwd, msg)
+ char *user;
+ char *passwd;
+ char **msg;
+{
+ char *tty;
+
+#ifdef USE_PAM
+ int pam_error;
+
+ pam_error = pam_start ("ppp", user, &PAM_conversation, &pamh);
+ if (pam_error != PAM_SUCCESS) {
+ *msg = (char *) pam_strerror (pamh, pam_error);
+ reopen_log();
+ return UPAP_AUTHNAK;
+ }
+ /*
+ * Define the fields for the credential validation
+ */
+
+ PAM_username = user;
+ PAM_password = passwd;
+ PAM_error = 0;
+ pam_set_item (pamh, PAM_TTY, devnam); /* this might be useful to some modules */
+
+ /*
+ * Validate the user
+ */
+ pam_error = pam_authenticate (pamh, PAM_SILENT);
+ if (pam_error == PAM_SUCCESS && !PAM_error) {
+ pam_error = pam_acct_mgmt (pamh, PAM_SILENT);
+ if (pam_error == PAM_SUCCESS)
+ pam_error = pam_open_session (pamh, PAM_SILENT);
+ }
+
+ *msg = (char *) pam_strerror (pamh, pam_error);
+
+ /*
+ * Clean up the mess
+ */
+ reopen_log(); /* apparently the PAM stuff does closelog() */
+ PAM_username = NULL;
+ PAM_password = NULL;
+ if (pam_error != PAM_SUCCESS)
+ return UPAP_AUTHNAK;
+#else /* #ifdef USE_PAM */
+
+/*
+ * Use the non-PAM methods directly
+ */
+
+#ifdef HAS_SHADOW
+ struct spwd *spwd;
+ struct spwd *getspnam();
+#endif
+ struct passwd *pw = getpwnam(user);
+
+ endpwent();
+ if (pw == NULL)
+ return (UPAP_AUTHNAK);
+
+#ifdef HAS_SHADOW
+ spwd = getspnam(user);
+ endspent();
+ if (spwd) {
+ /* check the age of the password entry */
+ long now = time(NULL) / 86400L;
+
+ if ((spwd->sp_expire > 0 && now >= spwd->sp_expire)
+ || ((spwd->sp_max >= 0 && spwd->sp_max < 10000)
+ && spwd->sp_lstchg >= 0
+ && now >= spwd->sp_lstchg + spwd->sp_max)) {
+ warn("Password for %s has expired", user);
+ return (UPAP_AUTHNAK);
+ }
+ pw->pw_passwd = spwd->sp_pwdp;
+ }
+#endif
+
+ /*
+ * If no passwd, don't let them login.
+ */
+ if (pw->pw_passwd == NULL || strlen(pw->pw_passwd) < 2
+ || strcmp(crypt(passwd, pw->pw_passwd), pw->pw_passwd) != 0)
+ return (UPAP_AUTHNAK);
+
+#endif /* #ifdef USE_PAM */
+
+ /*
+ * Write a wtmp entry for this user.
+ */
+
+ tty = devnam;
+ if (strncmp(tty, "/dev/", 5) == 0)
+ tty += 5;
+ logwtmp(tty, user, remote_name); /* Add wtmp login entry */
+
+#if defined(_PATH_LASTLOG) && !defined(USE_PAM)
+ if (pw != (struct passwd *)NULL) {
+ struct lastlog ll;
+ int fd;
+
+ if ((fd = open(_PATH_LASTLOG, O_RDWR, 0)) >= 0) {
+ (void)lseek(fd, (off_t)(pw->pw_uid * sizeof(ll)), SEEK_SET);
+ memset((void *)&ll, 0, sizeof(ll));
+ (void)time(&ll.ll_time);
+ (void)strncpy(ll.ll_line, tty, sizeof(ll.ll_line));
+ (void)write(fd, (char *)&ll, sizeof(ll));
+ (void)close(fd);
+ }
+ }
+#endif /* _PATH_LASTLOG and not USE_PAM */
+
+ info("user %s logged in", user);
+ logged_in = 1;
+
+ return (UPAP_AUTHACK);
+}
+
+/*
+ * plogout - Logout the user.
+ */
+static void
+plogout()
+{
+#ifdef USE_PAM
+ int pam_error;
+
+ if (pamh != NULL) {
+ pam_error = pam_close_session (pamh, PAM_SILENT);
+ pam_end (pamh, pam_error);
+ pamh = NULL;
+ }
+ /* Apparently the pam stuff does closelog(). */
+ reopen_log();
+#else /* ! USE_PAM */
+ char *tty;
+
+ tty = devnam;
+ if (strncmp(tty, "/dev/", 5) == 0)
+ tty += 5;
+ logwtmp(tty, "", ""); /* Wipe out utmp logout entry */
+#endif /* ! USE_PAM */
+ logged_in = 0;
+}
+
+
+/*
+ * null_login - Check if a username of "" and a password of "" are
+ * acceptable, and iff so, set the list of acceptable IP addresses
+ * and return 1.
+ */
+static int
+null_login(unit)
+ int unit;
+{
+ char *filename;
+ FILE *f;
+ int i, ret;
+ struct wordlist *addrs, *opts;
+ char secret[MAXWORDLEN];
+
+ /*
+ * Open the file of pap secrets and scan for a suitable secret.
+ */
+ filename = _PATH_UPAPFILE;
+ addrs = NULL;
+ f = fopen(filename, "r");
+ if (f == NULL)
+ return 0;
+ check_access(f, filename);
+
+ i = scan_authfile(f, "", our_name, secret, &addrs, &opts, filename);
+ ret = i >= 0 && secret[0] == 0;
+ BZERO(secret, sizeof(secret));
+
+ if (ret)
+ set_allowed_addrs(unit, addrs, opts);
+ else if (opts != 0)
+ free_wordlist(opts);
+ if (addrs != 0)
+ free_wordlist(addrs);
+
+ fclose(f);
+ return ret;
+}
+
+
+/*
+ * get_pap_passwd - get a password for authenticating ourselves with
+ * our peer using PAP. Returns 1 on success, 0 if no suitable password
+ * could be found.
+ * Assumes passwd points to MAXSECRETLEN bytes of space (if non-null).
+ */
+static int
+get_pap_passwd(passwd)
+ char *passwd;
+{
+ char *filename;
+ FILE *f;
+ int ret;
+ char secret[MAXWORDLEN];
+
+ /*
+ * Check whether a plugin wants to supply this.
+ */
+ if (pap_passwd_hook) {
+ 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);
+ 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(lacks_ipp)
+ int *lacks_ipp;
+{
+ FILE *f;
+ int ret;
+ char *filename;
+ struct wordlist *addrs;
+
+ /* let the plugin decide, if there is one */
+ if (pap_check_hook) {
+ 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);
+ 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(client, server, need_ip, lacks_ipp)
+ char *client;
+ char *server;
+ int need_ip;
+ int *lacks_ipp;
+{
+ FILE *f;
+ int ret;
+ char *filename;
+ struct wordlist *addrs;
+
+ filename = _PATH_CHAPFILE;
+ f = fopen(filename, "r");
+ if (f == NULL)
+ return 0;
+
+ if (client != NULL && client[0] == 0)
+ client = NULL;
+ else if (server != NULL && server[0] == 0)
+ server = NULL;
+
+ ret = scan_authfile(f, client, server, NULL, &addrs, NULL, filename);
+ 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(unit, client, server, secret, secret_len, am_server)
+ int unit;
+ char *client;
+ char *server;
+ char *secret;
+ int *secret_len;
+ int am_server;
+{
+ FILE *f;
+ int ret, len;
+ char *filename;
+ struct wordlist *addrs, *opts;
+ char secbuf[MAXWORDLEN];
+
+ if (!am_server && passwd[0] != 0) {
+ strlcpy(secbuf, passwd, sizeof(secbuf));
+ } else {
+ filename = _PATH_CHAPFILE;
+ addrs = NULL;
+ secbuf[0] = 0;
+
+ f = fopen(filename, "r");
+ if (f == NULL) {
+ error("Can't open chap secret file %s: %m", filename);
+ return 0;
+ }
+ check_access(f, filename);
+
+ ret = scan_authfile(f, client, server, secbuf, &addrs, &opts, filename);
+ 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;
+}
+
+/*
+ * 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(unit, addrs, opts)
+ 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(unit, addr)
+ int unit;
+ u_int32_t addr;
+{
+ int ok;
+
+ /* don't allow loopback or multicast address */
+ if (bad_ip_adrs(addr))
+ return 0;
+
+ if (addresses[unit] != NULL) {
+ ok = ip_addr_check(addr, addresses[unit]);
+ if (ok >= 0)
+ return ok;
+ }
+ if (auth_required)
+ return 0; /* no addresses authorized */
+ return allow_any_ip || privileged || !have_route_to(addr);
+}
+
+static int
+ip_addr_check(addr, addrs)
+ u_int32_t addr;
+ struct permitted_ip *addrs;
+{
+ for (; ; ++addrs)
+ if ((addr & addrs->mask) == addrs->base)
+ return addrs->permit;
+}
+
+/*
+ * bad_ip_adrs - return 1 if the IP address is one we don't want
+ * to use, such as an address in the loopback net or a multicast address.
+ * addr is in network byte order.
+ */
+int
+bad_ip_adrs(addr)
+ u_int32_t addr;
+{
+ addr = ntohl(addr);
+ return (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(addrs)
+ 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;
+}
+
+/*
+ * check_access - complain if a secret file has too-liberal permissions.
+ */
+static void
+check_access(f, filename)
+ FILE *f;
+ char *filename;
+{
+ struct stat sbuf;
+
+ if (fstat(fileno(f), &sbuf) < 0) {
+ warn("cannot stat secret file %s: %m", filename);
+ } else if ((sbuf.st_mode & (S_IRWXG | S_IRWXO)) != 0) {
+ warn("Warning - secret file %s has world and/or group access",
+ filename);
+ }
+}
+
+
+/*
+ * scan_authfile - Scan an authorization file for a secret suitable
+ * for authenticating `client' on `server'. The return value is -1
+ * if no secret is found, otherwise >= 0. The return value has
+ * NONWILD_CLIENT set if the secret didn't have "*" for the client, and
+ * NONWILD_SERVER set if the secret didn't have "*" for the server.
+ * Any following words on the line up to a "--" (i.e. address authorization
+ * info) are placed in a wordlist and returned in *addrs. Any
+ * following words (extra options) are placed in a wordlist and
+ * returned in *opts.
+ * We assume secret is NULL or points to MAXWORDLEN bytes of space.
+ */
+static int
+scan_authfile(f, client, server, secret, addrs, opts, filename)
+ FILE *f;
+ char *client;
+ char *server;
+ char *secret;
+ struct wordlist **addrs;
+ struct wordlist **opts;
+ char *filename;
+{
+ int newline, xxx;
+ int got_flag, best_flag;
+ FILE *sf;
+ struct wordlist *ap, *addr_list, *alist, **app;
+ char word[MAXWORDLEN];
+ char atfile[MAXWORDLEN];
+ char lsecret[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 secret.
+ */
+ if (!getword(f, word, &newline, filename))
+ break;
+ if (newline)
+ 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 (;;) {
+ 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 (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(wp)
+ 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(wp)
+ struct wordlist *wp;
+{
+ struct wordlist *next;
+
+ while (wp != NULL) {
+ next = wp->next;
+ free(wp);
+ wp = next;
+ }
+}
+
+/*
+ * auth_script_done - called when the auth-up or auth-down script
+ * has finished.
+ */
+static void
+auth_script_done(arg)
+ 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(_PATH_AUTHDOWN);
+ }
+ break;
+ case s_down:
+ if (auth_state == s_up) {
+ auth_script_state = s_up;
+ auth_script(_PATH_AUTHUP);
+ }
+ break;
+ }
+}
+
+/*
+ * auth_script - execute a script with arguments
+ * interface-name peer-name real-user tty speed
+ */
+static void
+auth_script(script)
+ char *script;
+{
+ char strspeed[32];
+ struct passwd *pw;
+ char struid[32];
+ char *user_name;
+ char *argv[8];
+
+ if ((pw = getpwuid(getuid())) != NULL && pw->pw_name != NULL)
+ user_name = pw->pw_name;
+ else {
+ 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] = NULL;
+
+ auth_script_pid = run_program(script, argv, 0, auth_script_done, NULL);
+}