/* * $Id$ * * Copyright information at end of file. */ #define _BSD_SOURCE #include #include #include #include #include #include #include #include #include #include #include #include "md5.h" #include "support.h" extern char *crypt(const char *key, const char *salt); extern char *bigcrypt(const char *key, const char *salt); /* syslogging function for errors and other information */ void _log_err(int err, const char *format,...) { va_list args; va_start(args, format); openlog("PAM_unix", LOG_CONS | LOG_PID, LOG_AUTH); vsyslog(err, format, args); va_end(args); closelog(); } /* this is a front-end for module-application conversations */ static int converse(pam_handle_t * pamh, int ctrl, int nargs ,struct pam_message **message ,struct pam_response **response) { int retval; struct pam_conv *conv; D(("begin to converse")); retval = pam_get_item(pamh, PAM_CONV, (const void **) &conv); if (retval == PAM_SUCCESS) { retval = conv->conv(nargs, (const struct pam_message **) message ,response, conv->appdata_ptr); D(("returned from application's conversation function")); if (retval != PAM_SUCCESS && on(UNIX_DEBUG, ctrl)) { _log_err(LOG_DEBUG, "conversation failure [%s]" ,pam_strerror(pamh, retval)); } } else if (retval != PAM_CONV_AGAIN) { _log_err(LOG_ERR, "couldn't obtain coversation function [%s]" ,pam_strerror(pamh, retval)); } D(("ready to return from module conversation")); return retval; /* propagate error status */ } int _make_remark(pam_handle_t * pamh, unsigned int ctrl ,int type, const char *text) { int retval = PAM_SUCCESS; if (off(UNIX__QUIET, ctrl)) { struct pam_message *pmsg[1], msg[1]; struct pam_response *resp; pmsg[0] = &msg[0]; msg[0].msg = text; msg[0].msg_style = type; resp = NULL; retval = converse(pamh, ctrl, 1, pmsg, &resp); if (resp) { _pam_drop_reply(resp, 1); } } return retval; } /* * Beacause getlogin() is braindead and sometimes it just * doesn't work, we reimplement it here. */ char *PAM_getlogin(void) { struct utmp *ut, line; char *curr_tty, *retval; static char curr_user[sizeof(ut->ut_user) + 4]; retval = NULL; curr_tty = ttyname(0); if (curr_tty != NULL) { D(("PAM_getlogin ttyname: %s", curr_tty)); curr_tty += 5; setutent(); strncpy(line.ut_line, curr_tty, sizeof line.ut_line); if ((ut = getutline(&line)) != NULL) { strncpy(curr_user, ut->ut_user, sizeof(ut->ut_user)); retval = curr_user; } endutent(); } D(("PAM_getlogin retval: %s", retval)); return retval; } /* * set the control flags for the UNIX module. */ int _set_ctrl(int flags, int *remember, int argc, const char **argv) { unsigned int ctrl; D(("called.")); ctrl = UNIX_DEFAULTS; /* the default selection of options */ /* set some flags manually */ if (getuid() == 0 && !(flags & PAM_CHANGE_EXPIRED_AUTHTOK)) { D(("IAMROOT")); set(UNIX__IAMROOT, ctrl); } if (flags & PAM_UPDATE_AUTHTOK) { D(("UPDATE_AUTHTOK")); set(UNIX__UPDATE, ctrl); } if (flags & PAM_PRELIM_CHECK) { D(("PRELIM_CHECK")); set(UNIX__PRELIM, ctrl); } if (flags & PAM_DISALLOW_NULL_AUTHTOK) { D(("DISALLOW_NULL_AUTHTOK")); set(UNIX__NONULL, ctrl); } if (flags & PAM_SILENT) { D(("SILENT")); set(UNIX__QUIET, ctrl); } /* now parse the arguments to this module */ while (argc-- > 0) { int j; D(("pam_unix arg: %s", *argv)); for (j = 0; j < UNIX_CTRLS_; ++j) { if (unix_args[j].token && !strncmp(*argv, unix_args[j].token, strlen(unix_args[j].token))) { break; } } if (j >= UNIX_CTRLS_) { _log_err(LOG_ERR, "unrecognized option [%s]", *argv); } else { ctrl &= unix_args[j].mask; /* for turning things off */ ctrl |= unix_args[j].flag; /* for turning things on */ if (remember != NULL) { if (j == UNIX_REMEMBER_PASSWD) { *remember = strtol(*argv + 9, NULL, 10); if ((*remember == LONG_MIN) || (*remember == LONG_MAX)) *remember = -1; if (*remember > 400) *remember = 400; } } } ++argv; /* step to next argument */ } /* auditing is a more sensitive version of debug */ if (on(UNIX_AUDIT, ctrl)) { set(UNIX_DEBUG, ctrl); } /* return the set of flags */ D(("done.")); return ctrl; } static void _cleanup(pam_handle_t * pamh, void *x, int error_status) { _pam_delete(x); } /* ************************************************************** * * Useful non-trivial functions * * ************************************************************** */ /* * the following is used to keep track of the number of times a user fails * to authenticate themself. */ #define FAIL_PREFIX "-UN*X-FAIL-" #define UNIX_MAX_RETRIES 3 struct _pam_failed_auth { char *user; /* user that's failed to be authenticated */ char *name; /* attempt from user with name */ int id; /* uid of name'd user */ int count; /* number of failures so far */ }; #ifndef PAM_DATA_REPLACE #error "Need to get an updated libpam 0.52 or better" #endif static void _cleanup_failures(pam_handle_t * pamh, void *fl, int err) { int quiet; const char *service = NULL; struct _pam_failed_auth *failure; D(("called")); quiet = err & PAM_DATA_SILENT; /* should we log something? */ err &= PAM_DATA_REPLACE; /* are we just replacing data? */ failure = (struct _pam_failed_auth *) fl; if (failure != NULL) { if (!quiet && !err) { /* under advisement from Sun,may go away */ /* log the number of authentication failures */ if (failure->count > 1) { (void) pam_get_item(pamh, PAM_SERVICE ,(const void **) &service); _log_err(LOG_NOTICE ,"%d more authentication failure%s; %s(uid=%d) -> " "%s for %s service" ,failure->count - 1, failure->count == 2 ? "" : "s" ,failure->name ,failure->id ,failure->user ,service == NULL ? "**unknown**" : service ); if (failure->count > UNIX_MAX_RETRIES) { _log_err(LOG_ALERT ,"service(%s) ignoring max retries; %d > %d" ,service == NULL ? "**unknown**" : service ,failure->count ,UNIX_MAX_RETRIES); } } } _pam_delete(failure->user); /* tidy up */ _pam_delete(failure->name); /* tidy up */ free(failure); } } /* * _unix_blankpasswd() is a quick check for a blank password * * returns TRUE if user does not have a password * - to avoid prompting for one in such cases (CG) */ int _unix_blankpasswd(unsigned int ctrl, const char *name) { struct passwd *pwd = NULL; struct spwd *spwdent = NULL; char *salt = NULL; int retval; D(("called")); /* * This function does not have to be too smart if something goes * wrong, return FALSE and let this case to be treated somewhere * else (CG) */ if (on(UNIX__NONULL, ctrl)) return 0; /* will fail but don't let on yet */ /* UNIX passwords area */ pwd = getpwnam(name); /* Get password file entry... */ if (pwd != NULL) { if (strcmp( pwd->pw_passwd, "*NP*" ) == 0) { /* NIS+ */ uid_t save_euid, save_uid; save_euid = geteuid(); save_uid = getuid(); if (save_uid == pwd->pw_uid) setreuid( save_euid, save_uid ); else { setreuid( 0, -1 ); if (setreuid( -1, pwd->pw_uid ) == -1) { setreuid( -1, 0 ); setreuid( 0, -1 ); if(setreuid( -1, pwd->pw_uid ) == -1) /* Will fail elsewhere. */ return 0; } } spwdent = getspnam( name ); if (save_uid == pwd->pw_uid) setreuid( save_uid, save_euid ); else { if (setreuid( -1, 0 ) == -1) setreuid( save_uid, -1 ); setreuid( -1, save_euid ); } } else if (strcmp(pwd->pw_passwd, "x") == 0) { /* * ...and shadow password file entry for this user, * if shadowing is enabled */ spwdent = getspnam(name); } if (spwdent) salt = x_strdup(spwdent->sp_pwdp); else salt = x_strdup(pwd->pw_passwd); } /* Does this user have a password? */ if (salt == NULL) { retval = 0; } else { if (strlen(salt) == 0) retval = 1; else retval = 0; } /* tidy up */ if (salt) _pam_delete(salt); return retval; } /* * verify the password of a user */ #include #include static int _unix_run_helper_binary(pam_handle_t *pamh, const char *passwd, unsigned int ctrl) { int retval, child, fds[2]; D(("called.")); /* create a pipe for the password */ if (pipe(fds) != 0) { D(("could not make pipe")); return PAM_AUTH_ERR; } /* fork */ child = fork(); if (child == 0) { static char *args[] = { NULL, NULL }; static char *envp[] = { NULL }; /* XXX - should really tidy up PAM here too */ /* reopen stdin as pipe */ close(fds[1]); dup2(fds[0], STDIN_FILENO); /* exec binary helper */ args[0] = x_strdup(CHKPWD_HELPER); execve(CHKPWD_HELPER, args, envp); /* should not get here: exit with error */ D(("helper binary is not available")); exit(PAM_AUTHINFO_UNAVAIL); } else if (child > 0) { /* wait for child */ /* if the stored password is NULL */ if (off(UNIX__NONULL, ctrl)) { /* this means we've succeeded */ write(fds[1], "nullok\0\0", 8); } else { write(fds[1], "nonull\0\0", 8); } if (passwd != NULL) { /* send the password to the child */ write(fds[1], passwd, strlen(passwd)+1); passwd = NULL; } else { write(fds[1], "", 1); /* blank password */ } close(fds[0]); /* close here to avoid possible SIGPIPE above */ close(fds[1]); (void) waitpid(child, &retval, 0); /* wait for helper to complete */ retval = (retval == 0) ? PAM_SUCCESS:PAM_AUTH_ERR; } else { D(("fork failed")); retval = PAM_AUTH_ERR; } D(("returning %d", retval)); return retval; } int _unix_verify_password(pam_handle_t * pamh, const char *name ,const char *p, unsigned int ctrl) { struct passwd *pwd = NULL; struct spwd *spwdent = NULL; char *salt = NULL; char *pp = NULL; char *data_name; int retval; D(("called")); #ifdef HAVE_PAM_FAIL_DELAY if (off(UNIX_NODELAY, ctrl)) { D(("setting delay")); (void) pam_fail_delay(pamh, 2000000); /* 2 sec delay for on failure */ } #endif /* locate the entry for this user */ D(("locating user's record")); /* UNIX passwords area */ pwd = getpwnam(name); /* Get password file entry... */ if (pwd != NULL) { if (strcmp( pwd->pw_passwd, "*NP*" ) == 0) { /* NIS+ */ uid_t save_euid, save_uid; save_euid = geteuid(); save_uid = getuid(); if (save_uid == pwd->pw_uid) setreuid( save_euid, save_uid ); else { setreuid( 0, -1 ); if (setreuid( -1, pwd->pw_uid ) == -1) { setreuid( -1, 0 ); setreuid( 0, -1 ); if(setreuid( -1, pwd->pw_uid ) == -1) return PAM_CRED_INSUFFICIENT; } } spwdent = getspnam( name ); if (save_uid == pwd->pw_uid) setreuid( save_uid, save_euid ); else { if (setreuid( -1, 0 ) == -1) setreuid( save_uid, -1 ); setreuid( -1, save_euid ); } } else if (strcmp(pwd->pw_passwd, "x") == 0) { /* * ...and shadow password file entry for this user, * if shadowing is enabled */ spwdent = getspnam(name); } if (spwdent) salt = x_strdup(spwdent->sp_pwdp); else salt = x_strdup(pwd->pw_passwd); } data_name = (char *) malloc(sizeof(FAIL_PREFIX) + strlen(name)); if (data_name == NULL) { _log_err(LOG_CRIT, "no memory for data-name"); } else { strcpy(data_name, FAIL_PREFIX); strcpy(data_name + sizeof(FAIL_PREFIX) - 1, name); } retval = PAM_SUCCESS; if (pwd == NULL || salt == NULL || !strcmp(salt, "x")) { if (geteuid()) { /* we are not root perhaps this is the reason? Run helper */ D(("running helper binary")); retval = _unix_run_helper_binary(pamh, p, ctrl); } else { D(("user's record unavailable")); if (on(UNIX_AUDIT, ctrl)) { /* this might be a typo and the user has given a password instead of a username. Careful with this. */ _log_err(LOG_ALERT, "check pass; user (%s) unknown", name); } else { _log_err(LOG_ALERT, "check pass; user unknown"); } p = NULL; retval = PAM_AUTHINFO_UNAVAIL; } } else { if (!strlen(salt)) { /* the stored password is NULL */ if (off(UNIX__NONULL, ctrl)) { /* this means we've succeeded */ D(("user has empty password - access granted")); retval = PAM_SUCCESS; } else { D(("user has empty password - access denied")); retval = PAM_AUTH_ERR; } } else if (!p) { retval = PAM_AUTH_ERR; } else { if (!strncmp(salt, "$1$", 3)) { pp = Goodcrypt_md5(p, salt); if (strcmp(pp, salt) != 0) { pp = Brokencrypt_md5(p, salt); } } else { pp = bigcrypt(p, salt); } p = NULL; /* no longer needed here */ /* the moment of truth -- do we agree with the password? */ D(("comparing state of pp[%s] and salt[%s]", pp, salt)); if (strcmp(pp, salt) == 0) { retval = PAM_SUCCESS; } else { retval = PAM_AUTH_ERR; } } } if (retval == PAM_SUCCESS) { if (data_name) /* reset failures */ pam_set_data(pamh, data_name, NULL, _cleanup_failures); } else { if (data_name != NULL) { struct _pam_failed_auth *new = NULL; const struct _pam_failed_auth *old = NULL; /* get a failure recorder */ new = (struct _pam_failed_auth *) malloc(sizeof(struct _pam_failed_auth)); if (new != NULL) { new->user = x_strdup(name); new->id = getuid(); new->name = x_strdup(PAM_getlogin()? PAM_getlogin() : ""); /* any previous failures for this user ? */ pam_get_data(pamh, data_name, (const void **) &old); if (old != NULL) { new->count = old->count + 1; if (new->count >= UNIX_MAX_RETRIES) { retval = PAM_MAXTRIES; } } else { const char *service=NULL; (void) pam_get_item(pamh, PAM_SERVICE, (const void **)&service); _log_err(LOG_NOTICE ,"authentication failure; %s(uid=%d) -> " "%s for %s service" ,new->name ,new->id ,new->user ,service == NULL ? "**unknown**":service ); new->count = 1; } pam_set_data(pamh, data_name, new, _cleanup_failures); } else { _log_err(LOG_CRIT, "no memory for failure recorder"); } } } if (data_name) _pam_delete(data_name); if (salt) _pam_delete(salt); if (pp) _pam_overwrite(pp); D(("done [%d].", retval)); return retval; } /* * obtain a password from the user */ int _unix_read_password(pam_handle_t * pamh ,unsigned int ctrl ,const char *comment ,const char *prompt1 ,const char *prompt2 ,const char *data_name ,const char **pass) { int authtok_flag; int retval; const char *item; char *token; D(("called")); /* * make sure nothing inappropriate gets returned */ *pass = token = NULL; /* * which authentication token are we getting? */ authtok_flag = on(UNIX__OLD_PASSWD, ctrl) ? PAM_OLDAUTHTOK : PAM_AUTHTOK; /* * should we obtain the password from a PAM item ? */ if (on(UNIX_TRY_FIRST_PASS, ctrl) || on(UNIX_USE_FIRST_PASS, ctrl)) { retval = pam_get_item(pamh, authtok_flag, (const void **) &item); if (retval != PAM_SUCCESS) { /* very strange. */ _log_err(LOG_ALERT ,"pam_get_item returned error to unix-read-password" ); return retval; } else if (item != NULL) { /* we have a password! */ *pass = item; item = NULL; return PAM_SUCCESS; } else if (on(UNIX_USE_FIRST_PASS, ctrl)) { return PAM_AUTHTOK_RECOVER_ERR; /* didn't work */ } else if (on(UNIX_USE_AUTHTOK, ctrl) && off(UNIX__OLD_PASSWD, ctrl)) { return PAM_AUTHTOK_RECOVER_ERR; } } /* * getting here implies we will have to get the password from the * user directly. */ { struct pam_message msg[3], *pmsg[3]; struct pam_response *resp; int i, replies; /* prepare to converse */ if (comment != NULL && off(UNIX__QUIET, ctrl)) { pmsg[0] = &msg[0]; msg[0].msg_style = PAM_TEXT_INFO; msg[0].msg = comment; i = 1; } else { i = 0; } pmsg[i] = &msg[i]; msg[i].msg_style = PAM_PROMPT_ECHO_OFF; msg[i++].msg = prompt1; replies = 1; if (prompt2 != NULL) { pmsg[i] = &msg[i]; msg[i].msg_style = PAM_PROMPT_ECHO_OFF; msg[i++].msg = prompt2; ++replies; } /* so call the conversation expecting i responses */ resp = NULL; retval = converse(pamh, ctrl, i, pmsg, &resp); if (resp != NULL) { /* interpret the response */ if (retval == PAM_SUCCESS) { /* a good conversation */ token = x_strdup(resp[i - replies].resp); if (token != NULL) { if (replies == 2) { /* verify that password entered correctly */ if (!resp[i - 1].resp || strcmp(token, resp[i - 1].resp)) { _pam_delete(token); /* mistyped */ retval = PAM_AUTHTOK_RECOVER_ERR; _make_remark(pamh, ctrl ,PAM_ERROR_MSG, MISTYPED_PASS); } } } else { _log_err(LOG_NOTICE ,"could not recover authentication token"); } } /* * tidy up the conversation (resp_retcode) is ignored * -- what is it for anyway? AGM */ _pam_drop_reply(resp, i); } else { retval = (retval == PAM_SUCCESS) ? PAM_AUTHTOK_RECOVER_ERR : retval; } } if (retval != PAM_SUCCESS) { if (on(UNIX_DEBUG, ctrl)) _log_err(LOG_DEBUG, "unable to obtain a password"); return retval; } /* 'token' is the entered password */ if (off(UNIX_NOT_SET_PASS, ctrl)) { /* we store this password as an item */ retval = pam_set_item(pamh, authtok_flag, token); _pam_delete(token); /* clean it up */ if (retval != PAM_SUCCESS || (retval = pam_get_item(pamh, authtok_flag ,(const void **) &item)) != PAM_SUCCESS) { _log_err(LOG_CRIT, "error manipulating password"); return retval; } } else { /* * then store it as data specific to this module. pam_end() * will arrange to clean it up. */ retval = pam_set_data(pamh, data_name, (void *) token, _cleanup); if (retval != PAM_SUCCESS) { _log_err(LOG_CRIT, "error manipulating password data [%s]" ,pam_strerror(pamh, retval)); _pam_delete(token); return retval; } item = token; token = NULL; /* break link to password */ } *pass = item; item = NULL; /* break link to password */ return PAM_SUCCESS; } /* ****************************************************************** * * Copyright (c) Jan Rêkorajski 1999. * Copyright (c) Andrew G. Morgan 1996-8. * Copyright (c) Alex O. Yuriev, 1996. * Copyright (c) Cristian Gafton 1996. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, and the entire permission notice in its entirety, * including the disclaimer of warranties. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. The name of the author may not be used to endorse or promote * products derived from this software without specific prior * written permission. * * ALTERNATIVELY, this product may be distributed under the terms of * the GNU Public License, in which case the provisions of the GPL are * required INSTEAD OF the above restrictions. (This clause is * necessary due to a potential bad interaction between the GPL and * the restrictions contained in a BSD-style copyright.) * * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED * OF THE POSSIBILITY OF SUCH DAMAGE. */