X-Git-Url: http://git.ozlabs.org/?p=ppp.git;a=blobdiff_plain;f=pppd%2Fauth.c;h=cf042686a33557e14fb1f81ce29b83c7a28c787b;hp=716d849ae8546a51a0cefc12e5bac2fb44873d78;hb=fd25394d146bb83043189608d30dd0eeb983186d;hpb=a3630de20e34796f434a728bfd9cf1a961380c82 diff --git a/pppd/auth.c b/pppd/auth.c index 716d849..cf04268 100644 --- a/pppd/auth.c +++ b/pppd/auth.c @@ -32,7 +32,7 @@ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. */ -#define RCSID "$Id: auth.c,v 1.57 1999/08/13 06:46:10 paulus Exp $" +#define RCSID "$Id: auth.c,v 1.88 2002/10/27 12:56:26 fcusack Exp $" #include #include @@ -46,7 +46,7 @@ #include #include #include -#if defined(_PATH_LASTLOG) && defined(_linux_) +#if defined(_PATH_LASTLOG) && defined(__linux__) #include #endif @@ -64,10 +64,13 @@ #define PW_PPP PW_LOGIN #endif #endif +#include #include "pppd.h" #include "fsm.h" #include "lcp.h" +#include "ccp.h" +#include "ecp.h" #include "ipcp.h" #include "upap.h" #include "chap.h" @@ -90,12 +93,25 @@ char peer_authname[MAXNAMELEN]; /* Records which authentication operations haven't completed yet. */ static int auth_pending[NUM_PPP]; +/* Records which authentication operations have been completed. */ +int auth_done[NUM_PPP]; + /* 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; + +/* Remote telephone number, if available */ +char remote_number[MAXNAMELEN]; + +/* Wordlist giving remote telephone numbers which may connect. */ +static struct wordlist *permitted_numbers; + /* Extra options to apply, from the secrets file entry for the peer. */ static struct wordlist *extra_options; @@ -108,6 +124,40 @@ 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; + +/* Hook for a plugin to say whether it is OK if the peer + refuses to authenticate. */ +int (*null_auth_hook) __P((struct wordlist **paddrs, + struct wordlist **popts)) = NULL; + +int (*allowed_address_hook) __P((u_int32_t addr)) = NULL; + +/* A notifier for when the peer has authenticated itself, + and we are proceeding to the network phase. */ +struct notifier *auth_up_notifier = NULL; + +/* A notifier for when the link goes down. */ +struct notifier *link_down_notifier = NULL; + /* * This is used to ensure that we don't start an auth-up/down * script while one is already running. @@ -121,6 +171,8 @@ 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. */ @@ -128,17 +180,20 @@ 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 */ +#ifdef CHAPMS +bool refuse_mschap = 0; /* Don't wanna auth. ourselves with MS-CHAP */ +bool refuse_mschap_v2 = 0; /* Don't wanna auth. ourselves with MS-CHAPv2 */ +#else +bool refuse_mschap = 1; /* Don't wanna auth. ourselves with MS-CHAP */ +bool refuse_mschap_v2 = 1; /* Don't wanna auth. ourselves with MS-CHAPv2 */ +#endif bool usehostname = 0; /* Use hostname for our_name */ bool auth_required = 0; /* Always require authentication from peer */ bool allow_any_ip = 0; /* Allow peer to use any IP address */ bool explicit_remote = 0; /* User specified explicit remote name */ char remote_name[MAXNAMELEN]; /* Peer's name for authentication */ -/* Bits in auth_pending[] */ -#define PAP_WITHPEER 1 -#define PAP_PEER 2 -#define CHAP_WITHPEER 4 -#define CHAP_PEER 8 +static char *uafname; /* name of most recent +ua file */ extern char *crypt __P((const char *, const char *)); @@ -147,7 +202,7 @@ extern char *crypt __P((const char *, const char *)); 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 **, int *)); +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 *)); @@ -155,61 +210,140 @@ 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 **, 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 *)); +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 int set_permitted_number __P((char **)); static void check_access __P((FILE *, char *)); +static int wordlist_count __P((struct wordlist *)); + +#ifdef MAXOCTETS +static void check_maxoctets __P((void *)); +#endif /* * 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", 1, &auth_required }, + "Require PAP authentication from peer", + OPT_PRIOSUB | 1, &auth_required }, { "+pap", o_bool, &lcp_wantoptions[0].neg_upap, - "Require PAP authentication from peer", 1, &auth_required }, + "Require PAP authentication from peer", + OPT_ALIAS | OPT_PRIOSUB | 1, &auth_required }, + { "require-chap", o_bool, &auth_required, + "Require CHAP authentication from peer", + OPT_PRIOSUB | OPT_A2OR | MDTYPE_MD5, + &lcp_wantoptions[0].chap_mdtype }, + { "+chap", o_bool, &auth_required, + "Require CHAP authentication from peer", + OPT_ALIAS | OPT_PRIOSUB | OPT_A2OR | MDTYPE_MD5, + &lcp_wantoptions[0].chap_mdtype }, +#ifdef CHAPMS + { "require-mschap", o_bool, &auth_required, + "Require MS-CHAP authentication from peer", + OPT_PRIOSUB | OPT_A2OR | MDTYPE_MICROSOFT, + &lcp_wantoptions[0].chap_mdtype }, + { "+mschap", o_bool, &auth_required, + "Require MS-CHAP authentication from peer", + OPT_ALIAS | OPT_PRIOSUB | OPT_A2OR | MDTYPE_MICROSOFT, + &lcp_wantoptions[0].chap_mdtype }, + { "require-mschap-v2", o_bool, &auth_required, + "Require MS-CHAPv2 authentication from peer", + OPT_PRIOSUB | OPT_A2OR | MDTYPE_MICROSOFT_V2, + &lcp_wantoptions[0].chap_mdtype }, + { "+mschap-v2", o_bool, &auth_required, + "Require MS-CHAPv2 authentication from peer", + OPT_ALIAS | OPT_PRIOSUB | OPT_A2OR | MDTYPE_MICROSOFT_V2, + &lcp_wantoptions[0].chap_mdtype }, +#endif + { "refuse-pap", o_bool, &refuse_pap, "Don't agree to auth to peer with PAP", 1 }, { "-pap", o_bool, &refuse_pap, - "Don't allow PAP authentication with peer", 1 }, - { "require-chap", o_bool, &lcp_wantoptions[0].neg_chap, - "Require CHAP authentication from peer", 1, &auth_required }, - { "+chap", o_bool, &lcp_wantoptions[0].neg_chap, - "Require CHAP authentication from peer", 1, &auth_required }, + "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 }, + "Don't agree to auth to peer with CHAP", + OPT_A2CLRB | MDTYPE_MD5, + &lcp_allowoptions[0].chap_mdtype }, { "-chap", o_bool, &refuse_chap, - "Don't allow CHAP authentication with peer", 1 }, + "Don't allow CHAP authentication with peer", + OPT_ALIAS | OPT_A2CLRB | MDTYPE_MD5, + &lcp_allowoptions[0].chap_mdtype }, +#ifdef CHAPMS + { "refuse-mschap", o_bool, &refuse_mschap, + "Don't agree to auth to peer with MS-CHAP", + OPT_A2CLRB | MDTYPE_MICROSOFT, + &lcp_allowoptions[0].chap_mdtype }, + { "-mschap", o_bool, &refuse_mschap, + "Don't allow MS-CHAP authentication with peer", + OPT_ALIAS | OPT_A2CLRB | MDTYPE_MICROSOFT, + &lcp_allowoptions[0].chap_mdtype }, + { "refuse-mschap-v2", o_bool, &refuse_mschap_v2, + "Don't agree to auth to peer with MS-CHAPv2", + OPT_A2CLRB | MDTYPE_MICROSOFT_V2, + &lcp_allowoptions[0].chap_mdtype }, + { "-mschap-v2", o_bool, &refuse_mschap_v2, + "Don't allow MS-CHAPv2 authentication with peer", + OPT_ALIAS | OPT_A2CLRB | MDTYPE_MICROSOFT_V2, + &lcp_allowoptions[0].chap_mdtype }, +#endif + { "name", o_string, our_name, "Set local name for authentication", - OPT_PRIV|OPT_STATIC, NULL, MAXNAMELEN }, + 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_STATIC, NULL, MAXNAMELEN }, + "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_STATIC, + "Set remote name for authentication", OPT_PRIO | OPT_STATIC, &explicit_remote, MAXNAMELEN }, - { "auth", o_bool, &auth_required, - "Require authentication from peer", 1 }, - { "noauth", o_bool, &auth_required, - "Don't require peer to authenticate", OPT_PRIV, &allow_any_ip }, - { "login", o_bool, &uselogin, + + { "login", o_bool, &uselogin, "Use system password database for PAP", 1 }, + { "papcrypt", o_bool, &cryptpap, "PAP passwords are encrypted", 1 }, - { "+ua", o_special, setupapfile, - "Get PAP user and password from file" }, - { "password", o_string, passwd, - "Password for authenticating us to the peer", OPT_STATIC, - NULL, MAXSECRETLEN }, - { "privgroup", o_special, privgroup, - "Allow group members to use privileged options", OPT_PRIV }, + + { "privgroup", o_special, (void *)privgroup, + "Allow group members to use privileged options", OPT_PRIV | OPT_A2LIST }, + + { "allow-ip", o_special, (void *)set_noauth_addr, + "Set IP address(es) which can be used without authentication", + OPT_PRIV | OPT_A2LIST }, + + { "remotenumber", o_string, remote_number, + "Set remote telephone number for authentication", OPT_PRIO | OPT_STATIC, + NULL, MAXNAMELEN }, + + { "allow-number", o_special, (void *)set_permitted_number, + "Set telephone number(s) which are allowed to connect", + OPT_PRIV | OPT_A2LIST }, + { NULL } }; @@ -220,36 +354,47 @@ static int setupapfile(argv) char **argv; { - FILE * ufile; + 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(*argv, "r"); + ufile = fopen(fname, "r"); seteuid(0); if (ufile == NULL) { - option_error("unable to open user login data file %s", *argv); + option_error("unable to open user login data file %s", fname); return 0; } - check_access(ufile, *argv); + check_access(ufile, fname); + uafname = fname; /* get username */ - if (fgets(user, MAXNAMELEN - 1, ufile) == NULL - || fgets(passwd, MAXSECRETLEN - 1, ufile) == NULL){ - option_error("unable to read user login data file %s", *argv); + 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(user); - if (l > 0 && user[l-1] == '\n') - user[l-1] = 0; - l = strlen(passwd); - if (l > 0 && passwd[l-1] == '\n') - passwd[l-1] = 0; + 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); } @@ -280,6 +425,51 @@ privgroup(argv) } +/* + * 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; +} + + +/* + * set_permitted_number - set remote telephone number(s) that may connect. + */ +static int +set_permitted_number(argv) + char **argv; +{ + char *number = *argv; + int l = strlen(number) + 1; + struct wordlist *wp; + + wp = (struct wordlist *) malloc(sizeof(struct wordlist) + l); + if (wp == NULL) + novm("allow-number argument"); + wp->word = (char *) (wp + 1); + wp->next = permitted_numbers; + BCOPY(number, wp->word, l); + permitted_numbers = wp; + return 1; +} + + /* * An Open on LCP has requested a change from Dead to Establish phase. * Do what's necessary to bring the physical layer up. @@ -300,9 +490,13 @@ link_terminated(unit) { if (phase == PHASE_DEAD) return; - if (logged_in) - plogout(); - phase = PHASE_DEAD; + if (pap_logout_hook) { + pap_logout_hook(); + } else { + if (logged_in) + plogout(); + } + new_phase(PHASE_DEAD); notice("Connection terminated."); } @@ -316,8 +510,10 @@ link_down(unit) int i; struct protent *protp; + notify(link_down_notifier, 0); 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); } @@ -332,7 +528,7 @@ link_down(unit) num_np_open = 0; num_np_up = 0; if (phase != PHASE_DEAD) - phase = PHASE_TERMINATE; + new_phase(PHASE_ESTABLISH); } /* @@ -358,13 +554,17 @@ link_established(unit) && protp->lowerup != NULL) (*protp->lowerup)(unit); - if (auth_required && !(go->neg_chap || go->neg_upap)) { + if (auth_required && !(go->neg_upap || go->neg_chap)) { /* * We wanted the peer to authenticate itself, and it refused: - * 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 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 (!wo->neg_upap || !null_login(unit)) { + 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; @@ -372,17 +572,18 @@ link_established(unit) } } - phase = PHASE_AUTHENTICATE; + new_phase(PHASE_AUTHENTICATE); + used_login = 0; auth = 0; if (go->neg_chap) { - ChapAuthPeer(unit, our_name, go->chap_mdtype); + ChapAuthPeer(unit, our_name, CHAP_DIGEST(go->chap_mdtype)); auth |= CHAP_PEER; } else if (go->neg_upap) { upap_authpeer(unit); auth |= PAP_PEER; } if (ho->neg_chap) { - ChapAuthWithPeer(unit, user, ho->chap_mdtype); + ChapAuthWithPeer(unit, user, CHAP_DIGEST(ho->chap_mdtype)); auth |= CHAP_WITHPEER; } else if (ho->neg_upap) { if (passwd[0] == 0) { @@ -394,6 +595,7 @@ link_established(unit) auth |= PAP_WITHPEER; } auth_pending[unit] = auth; + auth_done[unit] = 0; if (!auth) network_phase(unit); @@ -408,10 +610,15 @@ network_phase(unit) { lcp_options *go = &lcp_gotoptions[unit]; + /* Log calling number. */ + if (*remote_number) + notice("peer from calling number %q authorized", remote_number); + /* * If the peer had to authenticate, run the auth-up script now. */ if (go->neg_chap || go->neg_upap) { + notify(auth_up_notifier, 0); auth_state = s_up; if (auth_script_state == s_down && auth_script_pid == 0) { auth_script_state = s_up; @@ -424,7 +631,7 @@ network_phase(unit) * If we negotiated callback, do it now. */ if (go->neg_cbcp) { - phase = PHASE_CALLBACK; + new_phase(PHASE_CALLBACK); (*cbcp_protent.open)(unit); return; } @@ -438,26 +645,64 @@ network_phase(unit) free_wordlist(extra_options); extra_options = 0; } - start_networks(); + start_networks(unit); } void -start_networks() +start_networks(unit) + int unit; { int i; struct protent *protp; + int ecp_required, mppe_required; + + new_phase(PHASE_NETWORK); + +#ifdef HAVE_MULTILINK + if (multilink) { + if (mp_join_bundle()) { + if (updetach && !nodetach) + detach(); + return; + } + } +#endif /* HAVE_MULTILINK */ - phase = PHASE_NETWORK; -#if 0 +#ifdef PPP_FILTER if (!demand) set_filters(&pass_filter, &active_filter); #endif + /* Start CCP and ECP */ + for (i = 0; (protp = protocols[i]) != NULL; ++i) + if ((protp->protocol == PPP_ECP || protp->protocol == PPP_CCP) + && protp->enabled_flag && protp->open != NULL) + (*protp->open)(0); + + /* + * Bring up other network protocols iff encryption is not required. + */ + ecp_required = ecp_gotoptions[unit].required; + mppe_required = ccp_gotoptions[unit].mppe; + if (!ecp_required && !mppe_required) + continue_networks(unit); +} + +void +continue_networks(unit) + int unit; +{ + int i; + struct protent *protp; + + /* + * Start the "real" network protocols. + */ for (i = 0; (protp = protocols[i]) != NULL; ++i) - if (protp->protocol < 0xC000 && protp->enabled_flag - && protp->open != NULL) { + if (protp->protocol < 0xC000 + && protp->protocol != PPP_CCP && protp->protocol != PPP_ECP + && protp->enabled_flag && protp->open != NULL) { (*protp->open)(0); - if (protp->protocol != PPP_CCP) - ++num_np_open; + ++num_np_open; } if (num_np_open == 0) @@ -483,8 +728,8 @@ auth_peer_fail(unit, protocol) * The peer has been successfully authenticated using `protocol'. */ void -auth_peer_success(unit, protocol, name, namelen) - int unit, protocol; +auth_peer_success(unit, protocol, prot_flavor, name, namelen) + int unit, protocol, prot_flavor; char *name; int namelen; { @@ -493,6 +738,19 @@ auth_peer_success(unit, protocol, name, namelen) switch (protocol) { case PPP_CHAP: bit = CHAP_PEER; + switch (prot_flavor) { + case CHAP_DIGEST_MD5: + bit |= CHAP_MD5_PEER; + break; +#ifdef CHAPMS + case CHAP_MICROSOFT: + bit |= CHAP_MS_PEER; + break; + case CHAP_MICROSOFT_V2: + bit |= CHAP_MS2_PEER; + break; +#endif + } break; case PPP_PAP: bit = PAP_PEER; @@ -509,7 +767,10 @@ auth_peer_success(unit, protocol, name, namelen) namelen = sizeof(peer_authname) - 1; BCOPY(name, peer_authname, namelen); peer_authname[namelen] = 0; - script_setenv("PEERNAME", peer_authname); + script_setenv("PEERNAME", peer_authname, 0); + + /* Save the authentication method for later. */ + auth_done[unit] |= bit; /* * If there is no more authentication still to be done, @@ -542,14 +803,27 @@ auth_withpeer_fail(unit, protocol) * We have successfully authenticated ourselves with the peer using `protocol'. */ void -auth_withpeer_success(unit, protocol) - int unit, protocol; +auth_withpeer_success(unit, protocol, prot_flavor) + int unit, protocol, prot_flavor; { int bit; switch (protocol) { case PPP_CHAP: bit = CHAP_WITHPEER; + switch (prot_flavor) { + case CHAP_DIGEST_MD5: + bit |= CHAP_MD5_WITHPEER; + break; +#ifdef CHAPMS + case CHAP_MICROSOFT: + bit |= CHAP_MS_WITHPEER; + break; + case CHAP_MICROSOFT_V2: + bit |= CHAP_MS2_WITHPEER; + break; +#endif + } break; case PPP_PAP: if (passwd_from_file) @@ -561,6 +835,9 @@ auth_withpeer_success(unit, protocol) bit = 0; } + /* Save the authentication method for later. */ + auth_done[unit] |= bit; + /* * If there is no more authentication still being done, * proceed to the network (or callback) phase. @@ -577,15 +854,22 @@ 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_limit > 0) - TIMEOUT(check_idle, NULL, idle_time_limit); + 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 @@ -594,6 +878,11 @@ np_up(unit, proto) if (maxconnect > 0) TIMEOUT(connect_time_expired, 0, maxconnect); +#ifdef MAXOCTETS + if (maxoctets > 0) + TIMEOUT(check_maxoctets, NULL, maxoctets_timeout); +#endif + /* * Detach now, if the updetach option was given. */ @@ -610,8 +899,13 @@ void np_down(unit, proto) int unit, proto; { - if (--num_np_up == 0 && idle_time_limit > 0) { + if (--num_np_up == 0) { UNTIMEOUT(check_idle, NULL); + UNTIMEOUT(connect_time_expired, NULL); +#ifdef MAXOCTETS + UNTIMEOUT(check_maxoctets, NULL); +#endif + new_phase(PHASE_NETWORK); } } @@ -628,28 +922,72 @@ np_finished(unit, proto) } } +#ifdef MAXOCTETS +static void +check_maxoctets(arg) + void *arg; +{ + int diff; + unsigned int used; + + update_link_stats(ifunit); + link_stats_valid=0; + + switch(maxoctets_dir) { + case PPP_OCTETS_DIRECTION_IN: + used = link_stats.bytes_in; + break; + case PPP_OCTETS_DIRECTION_OUT: + used = link_stats.bytes_out; + break; + case PPP_OCTETS_DIRECTION_MAXOVERAL: + case PPP_OCTETS_DIRECTION_MAXSESSION: + used = (link_stats.bytes_in > link_stats.bytes_out) ? link_stats.bytes_in : link_stats.bytes_out; + break; + default: + used = link_stats.bytes_in+link_stats.bytes_out; + break; + } + diff = maxoctets - used; + if(diff < 0) { + notice("Traffic limit reached. Limit: %u Used: %u", maxoctets, used); + lcp_close(0, "Traffic limit"); + need_holdoff = 0; + status = EXIT_TRAFFIC_LIMIT; + } else { + TIMEOUT(check_maxoctets, NULL, maxoctets_timeout); + } +} +#endif + /* * 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; + void *arg; { struct ppp_idle idle; time_t itime; + int tlim; if (!get_idle_time(0, &idle)) return; - itime = MIN(idle.xmit_idle, idle.recv_idle); - if (itime >= idle_time_limit) { + 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, idle_time_limit - itime); + TIMEOUT(check_idle, NULL, tlim); } } @@ -683,19 +1021,26 @@ auth_check_options() /* * If we have a default route, require the peer to authenticate - * unless the noauth option was given. + * unless the noauth option was given or the real user is root. */ - if (!auth_required && !allow_any_ip && have_route_to(0)) + if (!auth_required && !allow_any_ip && have_route_to(0) && !privileged) { auth_required = 1; + default_auth = 1; + } + + /* If we selected any CHAP flavors, we should probably negotiate it. :-) */ + if (wo->chap_mdtype) + wo->neg_chap = 1; /* If authentication is required, ask peer for CHAP or PAP. */ if (auth_required) { + allow_any_ip = 0; if (!wo->neg_chap && !wo->neg_upap) { - wo->neg_chap = 1; + wo->neg_chap = 1; wo->chap_mdtype = MDTYPE_ALL; wo->neg_upap = 1; } } else { - wo->neg_chap = 0; + wo->neg_chap = 0; wo->chap_mdtype = MDTYPE_NONE; wo->neg_upap = 0; } @@ -705,26 +1050,29 @@ auth_check_options() */ lacks_ip = 0; can_auth = wo->neg_upap && (uselogin || have_pap_secret(&lacks_ip)); - if (!can_auth && wo->neg_chap) { + 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) { - if (explicit_remote) + if (auth_required && !can_auth && noauth_addrs == NULL) { + if (default_auth) { option_error( -"The remote system (%s) is required to authenticate itself but I", - remote_name); - else +"By default the remote system is required to authenticate itself"); option_error( -"The remote system is required to authenticate itself but I"); - - if (!lacks_ip) +"(because this system has a default route to the internet)"); + } else if (explicit_remote) option_error( -"couldn't find any suitable secret (password) for it to use to do so."); +"The remote system (%s) is required to authenticate itself", + remote_name); else option_error( -"couldn't find any secret (password) which would let it use an IP address."); +"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); } @@ -743,7 +1091,7 @@ auth_reset(unit) lcp_options *ao = &lcp_allowoptions[0]; ao->neg_upap = !refuse_pap && (passwd[0] != 0 || get_pap_passwd(NULL)); - ao->neg_chap = !refuse_chap + ao->neg_chap = (!refuse_chap || !refuse_mschap || !refuse_mschap_v2) && (passwd[0] != 0 || have_chap_secret(user, (explicit_remote? remote_name: NULL), 0, NULL)); @@ -769,38 +1117,55 @@ auth_reset(unit) * In either case, msg points to an appropriate message. */ int -check_passwd(unit, auser, userlen, apasswd, passwdlen, msg, msglen) +check_passwd(unit, auser, userlen, apasswd, passwdlen, msg) int unit; char *auser; int userlen; char *apasswd; int passwdlen; char **msg; - int *msglen; { int ret; char *filename; FILE *f; - struct wordlist *addrs; + 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. */ - BCOPY(apasswd, passwd, passwdlen); - passwd[passwdlen] = '\0'; - BCOPY(auser, user, userlen); - user[userlen] = '\0'; - *msg = (char *) 0; + 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); + if (opts != 0) { + free_wordlist(opts); + } + 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 = NULL; + addrs = opts = NULL; ret = UPAP_AUTHNAK; f = fopen(filename, "r"); if (f == NULL) { @@ -808,31 +1173,33 @@ check_passwd(unit, auser, userlen, apasswd, passwdlen, msg, msglen) } else { check_access(f, filename); - if (scan_authfile(f, user, our_name, secret, &addrs, filename) < 0) { + if (scan_authfile(f, user, our_name, secret, &addrs, &opts, filename) < 0) { warn("no PAP secret found for %s", user); - } else if (secret[0] != 0) { - /* password given in pap-secrets - must match */ - if ((!cryptpap && strcmp(passwd, secret) == 0) - || strcmp(crypt(passwd, secret), secret) == 0) - ret = UPAP_AUTHACK; - else - warn("PAP authentication failure for %s", user); - } else if (uselogin) { - /* empty password in pap-secrets and login option */ - ret = plogin(user, passwd, msg, msglen); - if (ret == UPAP_AUTHNAK) - warn("PAP login failure for %s", user); } else { - /* empty password in pap-secrets and login option not used */ + /* + * If the secret is "@login", it means to check + * the password against the login database. + */ + int login_secret = strcmp(secret, "@login") == 0; ret = UPAP_AUTHACK; + if (uselogin || login_secret) { + /* login option or secret is @login */ + if ((ret = plogin(user, passwd, msg)) == UPAP_AUTHACK) + 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; + } } fclose(f); } if (ret == UPAP_AUTHNAK) { - if (*msg == (char *) 0) + if (**msg == 0) *msg = "Login incorrect"; - *msglen = strlen(*msg); /* * XXX can we ever get here more than once?? * Frustrate passwd stealer programs. @@ -845,17 +1212,18 @@ check_passwd(unit, auser, userlen, apasswd, passwdlen, msg, msglen) } if (attempts > 3) sleep((u_int) (attempts - 3) * 5); - if (addrs != NULL) - free_wordlist(addrs); + if (opts != NULL) + free_wordlist(opts); } else { attempts = 0; /* Reset count */ - if (*msg == (char *) 0) + if (**msg == 0) *msg = "Login ok"; - *msglen = strlen(*msg); - set_allowed_addrs(unit, addrs); + set_allowed_addrs(unit, addrs, opts); } + if (addrs != NULL) + free_wordlist(addrs); BZERO(passwd, sizeof(passwd)); BZERO(secret, sizeof(secret)); @@ -938,11 +1306,10 @@ static struct pam_conv PAM_conversation = { */ static int -plogin(user, passwd, msg, msglen) +plogin(user, passwd, msg) char *user; char *passwd; char **msg; - int *msglen; { char *tty; @@ -971,7 +1338,7 @@ plogin(user, passwd, msg, msglen) if (pam_error == PAM_SUCCESS && !PAM_error) { pam_error = pam_acct_mgmt (pamh, PAM_SILENT); if (pam_error == PAM_SUCCESS) - pam_open_session (pamh, PAM_SILENT); + pam_error = pam_open_session (pamh, PAM_SILENT); } *msg = (char *) pam_strerror (pamh, pam_error); @@ -1034,7 +1401,7 @@ plogin(user, passwd, msg, msglen) tty = devnam; if (strncmp(tty, "/dev/", 5) == 0) tty += 5; - logwtmp(tty, user, remote_name); /* Add wtmp login entry */ + logwtmp(tty, user, ifname); /* Add wtmp login entry */ #if defined(_PATH_LASTLOG) && !defined(USE_PAM) if (pw != (struct passwd *)NULL) { @@ -1098,30 +1465,40 @@ null_login(unit) char *filename; FILE *f; int i, ret; - struct wordlist *addrs; + struct wordlist *addrs, *opts; char secret[MAXWORDLEN]; + /* + * Check if a plugin wants to handle this. + */ + ret = -1; + if (null_auth_hook) + ret = (*null_auth_hook)(&addrs, &opts); + /* * Open the file of pap secrets and scan for a suitable secret. - * We don't accept a wildcard client. */ - filename = _PATH_UPAPFILE; - addrs = NULL; - f = fopen(filename, "r"); - if (f == NULL) - return 0; - check_access(f, filename); + if (ret <= 0) { + filename = _PATH_UPAPFILE; + addrs = NULL; + f = fopen(filename, "r"); + if (f == NULL) + return 0; + check_access(f, filename); - i = scan_authfile(f, "", our_name, secret, &addrs, filename); - ret = i >= 0 && (i & NONWILD_CLIENT) != 0 && secret[0] == 0; - BZERO(secret, sizeof(secret)); + i = scan_authfile(f, "", our_name, secret, &addrs, &opts, filename); + ret = i >= 0 && secret[0] == 0; + BZERO(secret, sizeof(secret)); + fclose(f); + } if (ret) - set_allowed_addrs(unit, addrs); - else + set_allowed_addrs(unit, addrs, opts); + else if (opts != 0) + free_wordlist(opts); + if (addrs != 0) free_wordlist(addrs); - fclose(f); return ret; } @@ -1139,18 +1516,25 @@ get_pap_passwd(passwd) char *filename; FILE *f; int ret; - struct wordlist *addrs; 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; - addrs = NULL; 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, filename); + secret, NULL, NULL, filename); fclose(f); if (ret < 0) return 0; @@ -1174,13 +1558,20 @@ have_pap_secret(lacks_ipp) 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, filename); + NULL, &addrs, NULL, filename); fclose(f); if (ret >= 0 && !some_ip_ok(addrs)) { if (lacks_ipp != 0) @@ -1212,6 +1603,13 @@ have_chap_secret(client, server, need_ip, lacks_ipp) char *filename; struct wordlist *addrs; + if (chap_check_hook) { + ret = (*chap_check_hook)(); + if (ret >= 0) { + return ret; + } + } + filename = _PATH_CHAPFILE; f = fopen(filename, "r"); if (f == NULL) @@ -1222,7 +1620,7 @@ have_chap_secret(client, server, need_ip, lacks_ipp) else if (server != NULL && server[0] == 0) server = NULL; - ret = scan_authfile(f, client, server, NULL, &addrs, filename); + 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) @@ -1253,11 +1651,17 @@ get_secret(unit, client, server, secret, secret_len, am_server) FILE *f; int ret, len; char *filename; - struct wordlist *addrs; + struct wordlist *addrs, *opts; char secbuf[MAXWORDLEN]; if (!am_server && passwd[0] != 0) { strlcpy(secbuf, passwd, sizeof(secbuf)); + } else if (!am_server && chap_passwd_hook) { + if ( (*chap_passwd_hook)(client, secbuf) < 0) { + error("Unable to obtain CHAP password for %s on %s from plugin", + client, server); + return 0; + } } else { filename = _PATH_CHAPFILE; addrs = NULL; @@ -1270,13 +1674,17 @@ get_secret(unit, client, server, secret, secret_len, am_server) } check_access(f, filename); - ret = scan_authfile(f, client, server, secbuf, &addrs, 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); + set_allowed_addrs(unit, addrs, opts); + else if (opts != 0) + free_wordlist(opts); + if (addrs != 0) + free_wordlist(addrs); } len = strlen(secbuf); @@ -1297,12 +1705,13 @@ get_secret(unit, client, server, secret, secret_len, am_server) * and leaves the following words in extra_options. */ static void -set_allowed_addrs(unit, addrs) +set_allowed_addrs(unit, addrs, opts) int unit; struct wordlist *addrs; + struct wordlist *opts; { int n; - struct wordlist *ap, **pap; + struct wordlist *ap, **plink; struct permitted_ip *ip; char *ptr_word, *ptr_mask; struct hostent *hp; @@ -1316,27 +1725,23 @@ set_allowed_addrs(unit, addrs) addresses[unit] = NULL; if (extra_options != NULL) free_wordlist(extra_options); - extra_options = NULL; + extra_options = opts; /* - * Count the number of IP addresses given, and chop off - * any extra options for this peer. + * Count the number of IP addresses given. */ - for (n = 0, pap = &addrs; (ap = *pap) != NULL; pap = &ap->next, ++n) { - if (strcmp(ap->word, "--") == 0) { - /* rest are options */ - *pap = 0; - extra_options = ap->next; - free(ap); - break; - } - } + 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 */ @@ -1426,6 +1831,7 @@ set_allowed_addrs(unit, addrs) 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 */ @@ -1439,8 +1845,15 @@ set_allowed_addrs(unit, addrs) * 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 == 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; + } } /* @@ -1452,12 +1865,26 @@ auth_ip_addr(unit, addr) int unit; u_int32_t addr; { - if (addresses[unit] == NULL) { - if (auth_required) - return 0; /* no addresses authorized */ - return allow_any_ip || !have_route_to(addr); + int ok; + + /* don't allow loopback or multicast address */ + if (bad_ip_adrs(addr)) + return 0; + + if (allowed_address_hook) { + ok = allowed_address_hook(addr); + if (ok >= 0) return ok; + } + + if (addresses[unit] != NULL) { + ok = ip_addr_check(addr, addresses[unit]); + if (ok >= 0) + return ok; } - return ip_addr_check(addr, addresses[unit]); + + if (auth_required) + return 0; /* no addresses authorized */ + return allow_any_ip || privileged || !have_route_to(addr); } static int @@ -1465,10 +1892,6 @@ ip_addr_check(addr, addrs) u_int32_t addr; struct permitted_ip *addrs; { - /* don't allow loopback or multicast address */ - if (bad_ip_adrs(addr)) - return 0; - for (; ; ++addrs) if ((addr & addrs->mask) == addrs->base) return addrs->permit; @@ -1497,7 +1920,7 @@ some_ip_ok(addrs) struct wordlist *addrs; { for (; addrs != 0; addrs = addrs->next) { - if (strcmp(addrs->word, "-") == 0) + if (addrs->word[0] == '-') break; if (addrs->word[0] != '!') return 1; /* some IP address is allowed */ @@ -1505,6 +1928,34 @@ some_ip_ok(addrs) return 0; } +/* + * auth_number - check whether the remote number is allowed to connect. + * Returns 1 if authorized, 0 otherwise. + */ +int +auth_number() +{ + struct wordlist *wp = permitted_numbers; + int l; + + /* Allow all if no authorization list. */ + if (!wp) + return 1; + + /* Allow if we have a match in the authorization list. */ + while (wp) { + /* trailing '*' wildcard */ + l = strlen(wp->word); + if ((wp->word)[l - 1] == '*') + l--; + if (!strncasecmp(wp->word, remote_number, l)) + return 1; + wp = wp->next; + } + + return 0; +} + /* * check_access - complain if a secret file has too-liberal permissions. */ @@ -1530,29 +1981,34 @@ check_access(f, filename) * 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 (i.e. address authorization - * info) are placed in a wordlist and returned in *addrs. + * 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, filename) +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, *alast; + 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??? */ @@ -1606,46 +2062,44 @@ scan_authfile(f, client, server, secret, addrs, filename) if (newline) continue; - /* - * Special syntax: @filename means read secret from file. - */ - if (word[0] == '@') { - 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); + 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); - continue; } - fclose(sf); - } - if (secret != NULL) strlcpy(lsecret, word, sizeof(lsecret)); + } /* * Now read address authorization info and make a wordlist. */ - alist = alast = NULL; + app = &alist; for (;;) { if (!getword(f, word, &newline, filename) || newline) break; - ap = (struct wordlist *) malloc(sizeof(struct wordlist)); + ap = (struct wordlist *) + malloc(sizeof(struct wordlist) + strlen(word) + 1); if (ap == NULL) novm("authorized addresses"); - ap->next = NULL; - ap->word = strdup(word); - if (ap->word == NULL) - novm("authorized address"); - if (alist == NULL) - alist = ap; - else - alast->next = ap; - alast = ap; + ap->word = (char *) (ap + 1); + strcpy(ap->word, word); + *app = ap; + app = &ap->next; } + *app = NULL; /* * This is the best so far; remember it. @@ -1661,6 +2115,20 @@ scan_authfile(f, client, server, secret, addrs, filename) 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) @@ -1669,6 +2137,20 @@ scan_authfile(f, client, server, secret, addrs, filename) 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. */