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
31 /*
32 * There are three cases in which the file system will clear the setuid or
33 * setgid bits on a file when running unprivileged:
34 *
35 * - When the file is chown()'d and either of the uid or the gid is changed.
36 * (currently, only changing the file gid applies, as privilege is required
37 * to change the uid).
38 *
39 * - The file is written to successfully.
40 *
41 * - An extended attribute of the file is written to successfully.
42 *
43 * In each case, check that the flags are cleared if unprivileged, and that
44 * they aren't cleared if privileged.
45 *
46 * We can't use expect() as we're looking for side-effects rather than
47 * success/failure of the system call.
48 */
49
50 #include <sys/types.h>
51 #include <sys/extattr.h>
52 #include <sys/stat.h>
53
54 #include <err.h>
55 #include <fcntl.h>
56 #include <stdlib.h>
57 #include <string.h>
58 #include <unistd.h>
59
60 #include "main.h"
61
62 static char fpath[1024];
63 static int fpath_initialized;
64
65 /*
66 * If running as root, check that SUID is still set; otherwise, check that it
67 * is not.
68 */
69 static void
confirm_sugid(char * test_case,int asroot,int injail)70 confirm_sugid(char *test_case, int asroot, int injail)
71 {
72 struct stat sb;
73
74 if (stat(fpath, &sb) < 0) {
75 warn("%s stat(%s)", test_case, fpath);
76 return;
77 }
78 if (asroot) {
79 if (!(sb.st_mode & S_ISUID))
80 warnx("%s(root, %s): !SUID", test_case, injail ?
81 "jail" : "!jail");
82 } else {
83 if (sb.st_mode & S_ISUID)
84 warnx("%s(!root, %s): SUID", test_case, injail ?
85 "jail" : "!jail");
86 }
87 }
88
89 int
priv_vfs_clearsugid_setup(int asroot,int injail,struct test * test)90 priv_vfs_clearsugid_setup(int asroot, int injail, struct test *test)
91 {
92
93 setup_file("priv_vfs_clearsugid_setup: fpath", fpath, UID_OWNER,
94 GID_OTHER, 0600 | S_ISUID);
95 fpath_initialized = 1;
96 return (0);
97 }
98
99 void
priv_vfs_clearsugid_chgrp(int asroot,int injail,struct test * test)100 priv_vfs_clearsugid_chgrp(int asroot, int injail, struct test *test)
101 {
102
103 if (chown(fpath, -1, asroot ? GID_WHEEL : GID_OWNER) < 0)
104 err(-1, "priv_vfs_clearsugid_chgrp(%s, %s): chrgrp",
105 asroot ? "root" : "!root", injail ? "jail" : "!jail");
106 confirm_sugid("priv_vfs_clearsugid_chgrp", asroot, injail);
107 }
108
109 #define EA_NAMESPACE EXTATTR_NAMESPACE_USER
110 #define EA_NAME "clearsugid"
111 #define EA_DATA "test"
112 #define EA_SIZE (strlen(EA_DATA))
113
114 void
priv_vfs_clearsugid_extattr(int asroot,int injail,struct test * test)115 priv_vfs_clearsugid_extattr(int asroot, int injail, struct test *test)
116 {
117
118 if (extattr_set_file(fpath, EA_NAMESPACE, EA_NAME, EA_DATA, EA_SIZE)
119 < 0)
120 err(-1,
121 "priv_vfs_clearsugid_extattr(%s, %s): extattr_set_file",
122 asroot ? "root" : "!root", injail ? "jail" : "!jail");
123 confirm_sugid("priv_vfs_clearsugid_extattr", asroot, injail);
124 }
125
126 void
priv_vfs_clearsugid_write(int asroot,int injail,struct test * test)127 priv_vfs_clearsugid_write(int asroot, int injail, struct test *test)
128 {
129 int fd;
130
131 fd = open(fpath, O_RDWR);
132 if (fd < 0)
133 err(-1, "priv_vfs_clearsugid_write(%s, %s): open",
134 asroot ? "root" : "!root", injail ? "jail" : "!jail");
135 if (write(fd, EA_DATA, EA_SIZE) < 0)
136 err(-1, "priv_vfs_clearsugid_write(%s, %s): write",
137 asroot ? "root" : "!root", injail ? "jail" : "!jail");
138 (void)close(fd);
139 confirm_sugid("priv_vfs_clearsugid_write", asroot, injail);
140 }
141
142 void
priv_vfs_clearsugid_cleanup(int asroot,int injail,struct test * test)143 priv_vfs_clearsugid_cleanup(int asroot, int injail, struct test *test)
144 {
145
146 if (fpath_initialized) {
147 (void)unlink(fpath);
148 fpath_initialized = 0;
149 }
150 }
151