/* * 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 #include #include #include #include #include #include #include #include #include #include #include #if defined(_PATH_LASTLOG) && defined(_linux_) #include #endif #include #include #include #ifdef USE_PAM #include #endif #ifdef HAS_SHADOW #include #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" #include 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; u_int32_t a, mask, 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 { printf("*** getnetbyname is unsupported, please report bug! ***\n"); return; } 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); }