source: openpam/trunk/lib/openpam_borrow_cred.c @ 224

Last change on this file since 224 was 224, checked in by des, 11 years ago

Add #include <grp.h> which I missed due to namespace pollution.

Submitted by: Dmitry V. Levin <ldv@…>

File size: 3.6 KB
Line 
1/*-
2 * Copyright (c) 2002,2003 Networks Associates Technology, Inc.
3 * All rights reserved.
4 *
5 * This software was developed for the FreeBSD Project by ThinkSec AS and
6 * Network Associates Laboratories, the Security Research Division of
7 * Network Associates, Inc.  under DARPA/SPAWAR contract N66001-01-C-8035
8 * ("CBOSS"), as part of the DARPA CHATS research program.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. The name of the author may not be used to endorse or promote
19 *    products derived from this software without specific prior written
20 *    permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * $P4: //depot/projects/openpam/lib/openpam_borrow_cred.c#6 $
35 */
36
37#include <sys/param.h>
38
39#include <grp.h>
40#include <pwd.h>
41#include <stdlib.h>
42#include <unistd.h>
43
44#include <security/pam_appl.h>
45
46#include "openpam_impl.h"
47
48/*
49 * OpenPAM extension
50 *
51 * Temporarily borrow user credentials
52 */
53
54int
55openpam_borrow_cred(pam_handle_t *pamh,
56        const struct passwd *pwd)
57{
58        struct pam_saved_cred *scred;
59        int r;
60
61        ENTERI(pwd->pw_uid);
62        r = pam_get_data(pamh, PAM_SAVED_CRED, (const void **)&scred);
63        if (r == PAM_SUCCESS && scred != NULL) {
64                openpam_log(PAM_LOG_DEBUG,
65                    "already operating under borrowed credentials");
66                RETURNC(PAM_SYSTEM_ERR);
67        }
68        if (geteuid() != 0 && geteuid() != pwd->pw_uid) {
69                openpam_log(PAM_LOG_DEBUG, "called with non-zero euid: %d",
70                    (int)geteuid());
71                RETURNC(PAM_PERM_DENIED);
72        }
73        scred = calloc(1, sizeof *scred);
74        if (scred == NULL)
75                RETURNC(PAM_BUF_ERR);
76        scred->euid = geteuid();
77        scred->egid = getegid();
78        r = getgroups(NGROUPS_MAX, scred->groups);
79        if (r == -1) {
80                free(scred);
81                RETURNC(PAM_SYSTEM_ERR);
82        }
83        scred->ngroups = r;
84        r = pam_set_data(pamh, PAM_SAVED_CRED, scred, &openpam_free_data);
85        if (r != PAM_SUCCESS) {
86                free(scred);
87                RETURNC(r);
88        }
89        if (geteuid() == pwd->pw_uid)
90                RETURNC(PAM_SUCCESS);
91        if (initgroups(pwd->pw_name, pwd->pw_gid) == -1 ||
92              setegid(pwd->pw_gid) == -1 || seteuid(pwd->pw_uid) == -1) {
93                openpam_restore_cred(pamh);
94                RETURNC(PAM_SYSTEM_ERR);
95        }
96        RETURNC(PAM_SUCCESS);
97}
98
99/*
100 * Error codes:
101 *
102 *      =pam_set_data
103 *      PAM_SYSTEM_ERR
104 *      PAM_BUF_ERR
105 *      PAM_PERM_DENIED
106 */
107
108/**
109 * The =openpam_borrow_cred function saves the current credentials and
110 * switches to those of the user specified by its =pwd argument.  The
111 * affected credentials are the effective UID, the effective GID, and the
112 * group access list.  The original credentials can be restored using
113 * =openpam_restore_cred.
114 *
115 * >setegid
116 * >seteuid
117 * >setgroups
118 */
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