1/*-
2 * Copyright (c) 2006 nCircle Network Security, Inc.
3 * Copyright (c) 2007 Robert N. M. Watson
4 * All rights reserved.
5 *
6 * This software was developed by Robert N. M. Watson for the TrustedBSD
7 * Project under contract to nCircle Network Security, Inc.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR, NCIRCLE NETWORK SECURITY,
22 * INC., OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
24 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
25 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
26 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
27 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
28 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 *
30 * $FreeBSD$
31 */
32
33/*
34 * There are three cases in which the file system will clear the setuid or
35 * setgid bits on a file when running unprivileged:
36 *
37 * - When the file is chown()'d and either of the uid or the gid is changed.
38 *   (currently, only changing the file gid applies, as privilege is required
39 *   to change the uid).
40 *
41 * - The file is written to successfully.
42 *
43 * - An extended attribute of the file is written to successfully.
44 *
45 * In each case, check that the flags are cleared if unprivileged, and that
46 * they aren't cleared if privileged.
47 *
48 * We can't use expect() as we're looking for side-effects rather than
49 * success/failure of the system call.
50 */
51
52#include <sys/types.h>
53#include <sys/extattr.h>
54#include <sys/stat.h>
55
56#include <err.h>
57#include <fcntl.h>
58#include <stdlib.h>
59#include <string.h>
60#include <unistd.h>
61
62#include "main.h"
63
64static char fpath[1024];
65static int fpath_initialized;
66
67/*
68 * If running as root, check that SUID is still set; otherwise, check that it
69 * is not.
70 */
71static void
72confirm_sugid(char *test_case, int asroot, int injail)
73{
74	struct stat sb;
75
76	if (stat(fpath, &sb) < 0) {
77		warn("%s stat(%s)", test_case, fpath);
78		return;
79	}
80	if (asroot) {
81		if (!(sb.st_mode & S_ISUID))
82			warnx("%s(root, %s): !SUID", test_case, injail ?
83			    "jail" : "!jail");
84	} else {
85		if (sb.st_mode & S_ISUID)
86			warnx("%s(!root, %s): SUID", test_case, injail ?
87			    "jail" : "!jail");
88	}
89}
90
91int
92priv_vfs_clearsugid_setup(int asroot, int injail, struct test *test)
93{
94
95	setup_file("priv_vfs_clearsugid_setup: fpath", fpath, UID_OWNER,
96	    GID_OTHER, 0600 | S_ISUID);
97	fpath_initialized = 1;
98	return (0);
99}
100
101void
102priv_vfs_clearsugid_chgrp(int asroot, int injail, struct test *test)
103{
104
105	if (chown(fpath, -1, asroot ? GID_WHEEL : GID_OWNER) < 0)
106		err(-1, "priv_vfs_clearsugid_chgrp(%s, %s): chrgrp",
107		    asroot ? "root" : "!root", injail ? "jail" : "!jail");
108	confirm_sugid("priv_vfs_clearsugid_chgrp", asroot, injail);
109}
110
111#define	EA_NAMESPACE	EXTATTR_NAMESPACE_USER
112#define	EA_NAME		"clearsugid"
113#define	EA_DATA		"test"
114#define	EA_SIZE		(strlen(EA_DATA))
115
116void
117priv_vfs_clearsugid_extattr(int asroot, int injail, struct test *test)
118{
119
120	if (extattr_set_file(fpath, EA_NAMESPACE, EA_NAME, EA_DATA, EA_SIZE)
121	    < 0)
122		err(-1,
123		    "priv_vfs_clearsugid_extattr(%s, %s): extattr_set_file",
124		    asroot ? "root" : "!root", injail ? "jail" : "!jail");
125	confirm_sugid("priv_vfs_clearsugid_extattr", asroot, injail);
126}
127
128void
129priv_vfs_clearsugid_write(int asroot, int injail, struct test *test)
130{
131	int fd;
132
133	fd = open(fpath, O_RDWR);
134	if (fd < 0)
135		err(-1, "priv_vfs_clearsugid_write(%s, %s): open",
136		    asroot ? "root" : "!root", injail ? "jail" : "!jail");
137	if (write(fd, EA_DATA, EA_SIZE) < 0)
138		err(-1, "priv_vfs_clearsugid_write(%s, %s): write",
139		    asroot ? "root" : "!root", injail ? "jail" : "!jail");
140	(void)close(fd);
141	confirm_sugid("priv_vfs_clearsugid_write", asroot, injail);
142}
143
144void
145priv_vfs_clearsugid_cleanup(int asroot, int injail, struct test *test)
146{
147
148	if (fpath_initialized) {
149		(void)unlink(fpath);
150		fpath_initialized = 0;
151	}
152}
153