/*- * Copyright (c) 2002-2003 Networks Associates Technology, Inc. * Copyright (c) 2004-2011 Dag-Erling Smørgrav * All rights reserved. * * This software was developed for the FreeBSD Project by ThinkSec AS and * Network Associates Laboratories, the Security Research Division of * Network Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 * ("CBOSS"), as part of the DARPA CHATS research program. * * 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, this list of conditions and the following disclaimer. * 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. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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. */ #ifdef HAVE_CONFIG_H # include "config.h" #endif #include #include #include #include #include #include #include #include "openpam_impl.h" #include "openpam_cred.h" /* * OpenPAM extension * * Temporarily borrow user credentials */ int openpam_borrow_cred(pam_handle_t *pamh, const struct passwd *pwd) { struct pam_saved_cred *scred; const void *scredp; int r; ENTERI(pwd->pw_uid); r = pam_get_data(pamh, PAM_SAVED_CRED, &scredp); if (r == PAM_SUCCESS && scredp != NULL) { openpam_log(PAM_LOG_LIBDEBUG, "already operating under borrowed credentials"); RETURNC(PAM_SYSTEM_ERR); } if (geteuid() != 0 && geteuid() != pwd->pw_uid) { openpam_log(PAM_LOG_LIBDEBUG, "called with non-zero euid: %d", (int)geteuid()); RETURNC(PAM_PERM_DENIED); } scred = calloc(1, sizeof *scred); if (scred == NULL) RETURNC(PAM_BUF_ERR); scred->euid = geteuid(); scred->egid = getegid(); r = getgroups(NGROUPS_MAX, scred->groups); if (r < 0) { FREE(scred); RETURNC(PAM_SYSTEM_ERR); } scred->ngroups = r; r = pam_set_data(pamh, PAM_SAVED_CRED, scred, &openpam_free_data); if (r != PAM_SUCCESS) { FREE(scred); RETURNC(r); } if (geteuid() == pwd->pw_uid) RETURNC(PAM_SUCCESS); if (initgroups(pwd->pw_name, pwd->pw_gid) < 0 || setegid(pwd->pw_gid) < 0 || seteuid(pwd->pw_uid) < 0) { openpam_restore_cred(pamh); RETURNC(PAM_SYSTEM_ERR); } RETURNC(PAM_SUCCESS); } /* * Error codes: * * =pam_set_data * PAM_SYSTEM_ERR * PAM_BUF_ERR * PAM_PERM_DENIED */ /** * The =openpam_borrow_cred function saves the current credentials and * switches to those of the user specified by its =pwd argument. * The affected credentials are the effective UID, the effective GID, and * the group access list. * The original credentials can be restored using =openpam_restore_cred. * * >setegid 2 * >seteuid 2 * >setgroups 2 */