123 lines
3.8 KiB
C
123 lines
3.8 KiB
C
/*-
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* Copyright (c) 2002-2003 Networks Associates Technology, Inc.
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* Copyright (c) 2004-2007 Dag-Erling Smørgrav
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* All rights reserved.
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*
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* This software was developed for the FreeBSD Project by ThinkSec AS and
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* Network Associates Laboratories, the Security Research Division of
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* Network Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035
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* ("CBOSS"), as part of the DARPA CHATS research program.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id: openpam_borrow_cred.c,v 1.6 2008/01/27 01:22:58 christos Exp $
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*/
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#include <sys/param.h>
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#include <grp.h>
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#include <limits.h>
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#include <pwd.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <security/pam_appl.h>
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#include "openpam_impl.h"
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/*
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* OpenPAM extension
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*
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* Temporarily borrow user credentials
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*/
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int
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openpam_borrow_cred(pam_handle_t *pamh,
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const struct passwd *pwd)
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{
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struct pam_saved_cred *scred;
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const void *scredp;
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int r;
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ENTERI(pwd->pw_uid);
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r = pam_get_data(pamh, PAM_SAVED_CRED, &scredp);
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if (r == PAM_SUCCESS && scredp != NULL) {
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openpam_log(PAM_LOG_DEBUG,
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"already operating under borrowed credentials");
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RETURNC(PAM_SYSTEM_ERR);
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}
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if (geteuid() != 0 && geteuid() != pwd->pw_uid) {
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openpam_log(PAM_LOG_DEBUG, "called with non-zero euid: %d",
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(int)geteuid());
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RETURNC(PAM_PERM_DENIED);
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}
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scred = calloc((size_t)1, sizeof *scred);
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if (scred == NULL)
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RETURNC(PAM_BUF_ERR);
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scred->euid = geteuid();
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scred->egid = getegid();
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r = getgroups(NGROUPS_MAX, scred->groups);
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if (r < 0) {
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FREE(scred);
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RETURNC(PAM_SYSTEM_ERR);
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}
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scred->ngroups = r;
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r = pam_set_data(pamh, PAM_SAVED_CRED, scred, &openpam_free_data);
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if (r != PAM_SUCCESS) {
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FREE(scred);
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RETURNC(r);
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}
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if (geteuid() == pwd->pw_uid)
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RETURNC(PAM_SUCCESS);
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if (initgroups(pwd->pw_name, pwd->pw_gid) < 0 ||
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setegid(pwd->pw_gid) < 0 || seteuid(pwd->pw_uid) < 0) {
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openpam_restore_cred(pamh);
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RETURNC(PAM_SYSTEM_ERR);
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}
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RETURNC(PAM_SUCCESS);
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/*NOTREACHED*/
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}
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/*
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* Error codes:
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*
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* =pam_set_data
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* PAM_SYSTEM_ERR
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* PAM_BUF_ERR
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* PAM_PERM_DENIED
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*/
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/**
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* The =openpam_borrow_cred function saves the current credentials and
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* switches to those of the user specified by its =pwd argument.
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* The affected credentials are the effective UID, the effective GID, and
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* the group access list.
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* The original credentials can be restored using =openpam_restore_cred.
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*
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* >setegid 2
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* >seteuid 2
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* >setgroups 2
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*/
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