diff options
Diffstat (limited to 'lib/openpam_borrow_cred.c')
| -rw-r--r-- | lib/openpam_borrow_cred.c | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/lib/openpam_borrow_cred.c b/lib/openpam_borrow_cred.c new file mode 100644 index 0000000..79a349f --- /dev/null +++ b/lib/openpam_borrow_cred.c @@ -0,0 +1,121 @@ +/*- + * Copyright (c) 2002-2003 Networks Associates Technology, Inc. + * Copyright (c) 2004-2007 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. + * + * $Id: openpam_borrow_cred.c 408 2007-12-21 11:36:24Z des $ + */ + +#include <sys/param.h> + +#include <grp.h> +#include <limits.h> +#include <pwd.h> +#include <stdlib.h> +#include <unistd.h> + +#include <security/pam_appl.h> + +#include "openpam_impl.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_DEBUG, + "already operating under borrowed credentials"); + RETURNC(PAM_SYSTEM_ERR); + } + if (geteuid() != 0 && geteuid() != pwd->pw_uid) { + openpam_log(PAM_LOG_DEBUG, "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 + */ |
