xref: /freebsd/contrib/openpam/lib/libpam/openpam_restore_cred.c (revision 6be3386466ab79a84b48429ae66244f21526d3df)
1 /*-
2  * Copyright (c) 2002-2003 Networks Associates Technology, Inc.
3  * Copyright (c) 2004-2011 Dag-Erling Smørgrav
4  * All rights reserved.
5  *
6  * This software was developed for the FreeBSD Project by ThinkSec AS and
7  * Network Associates Laboratories, the Security Research Division of
8  * Network Associates, Inc.  under DARPA/SPAWAR contract N66001-01-C-8035
9  * ("CBOSS"), as part of the DARPA CHATS research program.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. The name of the author may not be used to endorse or promote
20  *    products derived from this software without specific prior written
21  *    permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  *
35  * $OpenPAM: openpam_restore_cred.c 938 2017-04-30 21:34:42Z des $
36  */
37 
38 #ifdef HAVE_CONFIG_H
39 # include "config.h"
40 #endif
41 
42 #include <sys/param.h>
43 
44 #include <grp.h>
45 #include <limits.h>
46 #include <pwd.h>
47 #include <stdlib.h>
48 #include <unistd.h>
49 
50 #include <security/pam_appl.h>
51 
52 #include "openpam_impl.h"
53 #include "openpam_cred.h"
54 
55 /*
56  * OpenPAM extension
57  *
58  * Restore credentials
59  */
60 
61 int
62 openpam_restore_cred(pam_handle_t *pamh)
63 {
64 	const struct pam_saved_cred *scred;
65 	const void *scredp;
66 	int r;
67 
68 	ENTER();
69 	r = pam_get_data(pamh, PAM_SAVED_CRED, &scredp);
70 	if (r != PAM_SUCCESS)
71 		RETURNC(r);
72 	if (scredp == NULL)
73 		RETURNC(PAM_SYSTEM_ERR);
74 	scred = scredp;
75 	if (scred->euid != geteuid()) {
76 		if (seteuid(scred->euid) < 0 ||
77 		    setgroups(scred->ngroups, scred->groups) < 0 ||
78 		    setegid(scred->egid) < 0)
79 			RETURNC(PAM_SYSTEM_ERR);
80 	}
81 	pam_set_data(pamh, PAM_SAVED_CRED, NULL, NULL);
82 	RETURNC(PAM_SUCCESS);
83 }
84 
85 /*
86  * Error codes:
87  *
88  *	=pam_get_data
89  *	PAM_SYSTEM_ERR
90  */
91 
92 /**
93  * The =openpam_restore_cred function restores the credentials saved by
94  * =openpam_borrow_cred.
95  *
96  * >setegid 2
97  * >seteuid 2
98  * >setgroups 2
99  */
100