/* Unix SMB/CIFS implementation. Use PAM to update user passwords in the local SAM Copyright (C) Steve Langasek 1998-2003 This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */ /* indicate the following groups are defined */ #define PAM_SM_PASSWORD #include "includes.h" /* This is only used in the Sun implementation. FIXME: we really want a define here that distinguishes between the Solaris PAM and others (including FreeBSD). */ #ifndef LINUX #if defined(HAVE_SECURITY_PAM_APPL_H) #include <security/pam_appl.h> #elif defined(HAVE_PAM_PAM_APPL_H) #include <pam/pam_appl.h> #endif #endif #if defined(HAVE_SECURITY_PAM_MODULES_H) #include <security/pam_modules.h> #elif defined(HAVE_PAM_PAM_MODULES_H) #include <pam/pam_modules.h> #endif #include "general.h" #include "support.h" static int smb_update_db( pam_handle_t *pamh, int ctrl, const char *user, const char *pass_new ) { int retval; char *err_str = NULL; char *msg_str = NULL; retval = NT_STATUS_IS_OK(local_password_change(user, LOCAL_SET_PASSWORD, pass_new, &err_str, &msg_str)); if (!retval) { if (err_str) { make_remark(pamh, ctrl, PAM_ERROR_MSG, err_str ); } /* FIXME: what value is appropriate here? */ retval = PAM_AUTHTOK_ERR; } else { if (msg_str) { make_remark(pamh, ctrl, PAM_TEXT_INFO, msg_str ); } retval = PAM_SUCCESS; } SAFE_FREE(err_str); SAFE_FREE(msg_str); return retval; } /* data tokens */ #define _SMB_OLD_AUTHTOK "-SMB-OLD-PASS" #define _SMB_NEW_AUTHTOK "-SMB-NEW-PASS" /* * FUNCTION: pam_sm_chauthtok() * * This function is called twice by the PAM library, once with * PAM_PRELIM_CHECK set, and then again with PAM_UPDATE_AUTHTOK set. With * Linux-PAM, these two passes generally involve first checking the old * token and then changing the token. This is what we do here. * * Having obtained a new password. The function updates the * SMB_PASSWD_FILE file (normally, $(LIBDIR)/smbpasswd). */ int pam_sm_chauthtok(pam_handle_t *pamh, int flags, int argc, const char **argv) { unsigned int ctrl; int retval; struct samu *sampass = NULL; void (*oldsig_handler)(int); const char *user; char *pass_old; char *pass_new; /* Samba initialization. */ load_case_tables(); lp_set_in_client(True); ctrl = set_ctrl(pamh, flags, argc, argv); /* * First get the name of a user. No need to do anything if we can't * determine this. */ retval = pam_get_user( pamh, &user, "Username: " ); if (retval != PAM_SUCCESS) { if (on( SMB_DEBUG, ctrl )) { _log_err(pamh, LOG_DEBUG, "password: could not identify user"); } return retval; } if (on( SMB_DEBUG, ctrl )) { _log_err(pamh, LOG_DEBUG, "username [%s] obtained", user); } if (geteuid() != 0) { _log_err(pamh, LOG_DEBUG, "Cannot access samba password database, not running as root."); return PAM_AUTHINFO_UNAVAIL; } /* Getting into places that might use LDAP -- protect the app from a SIGPIPE it's not expecting */ oldsig_handler = CatchSignal(SIGPIPE, SIG_IGN); if (!initialize_password_db(False, NULL)) { _log_err(pamh, LOG_ALERT, "Cannot access samba password database" ); CatchSignal(SIGPIPE, oldsig_handler); return PAM_AUTHINFO_UNAVAIL; } /* obtain user record */ if ( !(sampass = samu_new( NULL )) ) { CatchSignal(SIGPIPE, oldsig_handler); return nt_status_to_pam(NT_STATUS_NO_MEMORY); } if (!pdb_getsampwnam(sampass,user)) { _log_err(pamh, LOG_ALERT, "Failed to find entry for user %s.", user); CatchSignal(SIGPIPE, oldsig_handler); return PAM_USER_UNKNOWN; } if (on( SMB_DEBUG, ctrl )) { _log_err(pamh, LOG_DEBUG, "Located account for %s", user); } if (flags & PAM_PRELIM_CHECK) { /* * obtain and verify the current password (OLDAUTHTOK) for * the user. */ char *Announce; if (_smb_blankpasswd( ctrl, sampass )) { TALLOC_FREE(sampass); CatchSignal(SIGPIPE, oldsig_handler); return PAM_SUCCESS; } /* Password change by root, or for an expired token, doesn't require authentication. Is this a good choice? */ if (getuid() != 0 && !(flags & PAM_CHANGE_EXPIRED_AUTHTOK)) { /* tell user what is happening */ #define greeting "Changing password for " Announce = SMB_MALLOC_ARRAY(char, sizeof(greeting)+strlen(user)); if (Announce == NULL) { _log_err(pamh, LOG_CRIT, "password: out of memory"); TALLOC_FREE(sampass); CatchSignal(SIGPIPE, oldsig_handler); return PAM_BUF_ERR; } strncpy( Announce, greeting, sizeof(greeting) ); strncpy( Announce+sizeof(greeting)-1, user, strlen(user)+1 ); #undef greeting set( SMB__OLD_PASSWD, ctrl ); retval = _smb_read_password( pamh, ctrl, Announce, "Current SMB password: ", NULL, _SMB_OLD_AUTHTOK, &pass_old ); SAFE_FREE( Announce ); if (retval != PAM_SUCCESS) { _log_err(pamh, LOG_NOTICE, "password - (old) token not obtained"); TALLOC_FREE(sampass); CatchSignal(SIGPIPE, oldsig_handler); return retval; } /* verify that this is the password for this user */ retval = _smb_verify_password( pamh, sampass, pass_old, ctrl ); } else { pass_old = NULL; retval = PAM_SUCCESS; /* root doesn't have to */ } pass_old = NULL; TALLOC_FREE(sampass); CatchSignal(SIGPIPE, oldsig_handler); return retval; } else if (flags & PAM_UPDATE_AUTHTOK) { /* * obtain the proposed password */ /* * get the old token back. NULL was ok only if root [at this * point we assume that this has already been enforced on a * previous call to this function]. */ if (off( SMB_NOT_SET_PASS, ctrl )) { retval = _pam_get_item( pamh, PAM_OLDAUTHTOK, &pass_old ); } else { retval = _pam_get_data( pamh, _SMB_OLD_AUTHTOK, &pass_old ); if (retval == PAM_NO_MODULE_DATA) { pass_old = NULL; retval = PAM_SUCCESS; } } if (retval != PAM_SUCCESS) { _log_err(pamh, LOG_NOTICE, "password: user not authenticated"); TALLOC_FREE(sampass); CatchSignal(SIGPIPE, oldsig_handler); return retval; } /* * use_authtok is to force the use of a previously entered * password -- needed for pluggable password strength checking * or other module stacking */ if (on( SMB_USE_AUTHTOK, ctrl )) { set( SMB_USE_FIRST_PASS, ctrl ); } retval = _smb_read_password( pamh, ctrl , NULL , "Enter new SMB password: " , "Retype new SMB password: " , _SMB_NEW_AUTHTOK , &pass_new ); if (retval != PAM_SUCCESS) { if (on( SMB_DEBUG, ctrl )) { _log_err(pamh, LOG_ALERT, "password: new password not obtained"); } pass_old = NULL; /* tidy up */ TALLOC_FREE(sampass); CatchSignal(SIGPIPE, oldsig_handler); return retval; } /* * At this point we know who the user is and what they * propose as their new password. Verify that the new * password is acceptable. */ if (pass_new[0] == '\0') { /* "\0" password = NULL */ pass_new = NULL; } retval = _pam_smb_approve_pass(pamh, ctrl, pass_old, pass_new); if (retval != PAM_SUCCESS) { _log_err(pamh, LOG_NOTICE, "new password not acceptable"); pass_new = pass_old = NULL; /* tidy up */ TALLOC_FREE(sampass); CatchSignal(SIGPIPE, oldsig_handler); return retval; } /* * By reaching here we have approved the passwords and must now * rebuild the smb password file. */ /* update the password database */ retval = smb_update_db(pamh, ctrl, user, pass_new); if (retval == PAM_SUCCESS) { uid_t uid; /* password updated */ if (!sid_to_uid(pdb_get_user_sid(sampass), &uid)) { _log_err(pamh, LOG_NOTICE, "Unable to get uid for user %s", pdb_get_username(sampass)); _log_err(pamh, LOG_NOTICE, "password for (%s) changed by (%s/%d)", user, uidtoname(getuid()), getuid()); } else { _log_err(pamh, LOG_NOTICE, "password for (%s/%d) changed by (%s/%d)", user, uid, uidtoname(getuid()), getuid()); } } else { _log_err(pamh, LOG_ERR, "password change failed for user %s", user); } pass_old = pass_new = NULL; if (sampass) { TALLOC_FREE(sampass); sampass = NULL; } } else { /* something has broken with the library */ _log_err(pamh, LOG_ALERT, "password received unknown request"); retval = PAM_ABORT; } if (sampass) { TALLOC_FREE(sampass); sampass = NULL; } TALLOC_FREE(sampass); CatchSignal(SIGPIPE, oldsig_handler); return retval; } /* static module data */ #ifdef PAM_STATIC struct pam_module _pam_smbpass_passwd_modstruct = { "pam_smbpass", NULL, NULL, NULL, NULL, NULL, pam_sm_chauthtok }; #endif