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
64 static char fpath[1024];
65 static int fpath_initialized;
66
67 /*
68 * If running as root, check that SUID is still set; otherwise, check that it
69 * is not.
70 */
71 static void
confirm_sugid(char * test_case,int asroot,int injail)72 confirm_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
91 int
priv_vfs_clearsugid_setup(int asroot,int injail,struct test * test)92 priv_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
101 void
priv_vfs_clearsugid_chgrp(int asroot,int injail,struct test * test)102 priv_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
116 void
priv_vfs_clearsugid_extattr(int asroot,int injail,struct test * test)117 priv_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
128 void
priv_vfs_clearsugid_write(int asroot,int injail,struct test * test)129 priv_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
144 void
priv_vfs_clearsugid_cleanup(int asroot,int injail,struct test * test)145 priv_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