1 /* $NetBSD: t_link.c,v 1.5 2022/03/30 16:35:28 christos Exp $ */
2
3 /*-
4 * Copyright (c) 2022 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Christos Zoulas.
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 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 #include <sys/param.h>
33 #include <sys/stat.h>
34 #include <sys/time.h>
35 #include <sys/sysctl.h>
36
37 #include <atf-c.h>
38 #include <libgen.h>
39 #include <limits.h>
40 #include <unistd.h>
41 #include <stdbool.h>
42
43 #include <rump/rump_syscalls.h>
44 #include <rump/rump.h>
45
46 #include "../common/h_fsmacros.h"
47 #include "h_macros.h"
48
49 #define USES_OWNER \
50 if (FSTYPE_MSDOS(tc)) \
51 atf_tc_skip("owner not supported by file system")
52 #define USES_USERLEVEL \
53 if (FSTYPE_PUFFS(tc) || FSTYPE_P2K_FFS(tc)) \
54 atf_tc_skip("userlevel pass not supported, " \
55 "since sysctl might not be set in underlying system")
56
57
58 static void
hardlink(const atf_tc_t * tc,const char * mp,uid_t u1,uid_t u2,bool sysctl,bool allowed)59 hardlink(const atf_tc_t *tc, const char *mp, uid_t u1, uid_t u2,
60 bool sysctl, bool allowed)
61 {
62 const char name[] = "foo";
63 const char link[] = "bar";
64 int one = 1, fd;
65
66 USES_OWNER;
67 USES_USERLEVEL;
68
69 FSTEST_ENTER();
70
71 if (sysctl) {
72 if (sysctlbyname(
73 "security.models.extensions.hardlink_check_uid",
74 NULL, 0, &one, sizeof(one)) == -1)
75 atf_tc_fail_errno("sysctlbyname");
76 }
77
78 rump_pub_lwproc_rfork(RUMP_RFCFDG);
79 if (rump_sys_chmod(".", 0777) == -1)
80 atf_tc_fail_errno("chmod");
81 if (rump_sys_setuid(u1) == -1)
82 atf_tc_fail_errno("setuid");
83 if ((fd = rump_sys_open(name, O_RDWR|O_CREAT, 0666)) == -1)
84 atf_tc_fail_errno("open");
85 if (rump_sys_close(fd) == -1)
86 atf_tc_fail_errno("close");
87 rump_pub_lwproc_releaselwp();
88
89 rump_pub_lwproc_rfork(RUMP_RFCFDG);
90 if (rump_sys_setuid(u2) == -1)
91 atf_tc_fail_errno("setuid");
92 if (rump_sys_link(name, link) == -1) {
93 if (errno != EOPNOTSUPP && allowed)
94 atf_tc_fail_errno("link");
95 } else {
96 if (!allowed)
97 atf_tc_fail("failed to disallow hard link");
98 }
99 rump_pub_lwproc_releaselwp();
100
101 FSTEST_EXIT();
102 }
103
104
105 static void
hardlink_sameuser(const atf_tc_t * tc,const char * mp)106 hardlink_sameuser(const atf_tc_t *tc, const char *mp)
107 {
108 hardlink(tc, mp, 1, 1, false, true);
109 }
110
111 static void
hardlink_sameuser_sysctl(const atf_tc_t * tc,const char * mp)112 hardlink_sameuser_sysctl(const atf_tc_t *tc, const char *mp)
113 {
114 hardlink(tc, mp, 1, 1, true, true);
115 }
116
117 static void
hardlink_otheruser(const atf_tc_t * tc,const char * mp)118 hardlink_otheruser(const atf_tc_t *tc, const char *mp)
119 {
120 hardlink(tc, mp, 1, 2, false, true);
121 }
122
123 static void
hardlink_otheruser_sysctl(const atf_tc_t * tc,const char * mp)124 hardlink_otheruser_sysctl(const atf_tc_t *tc, const char *mp)
125 {
126 hardlink(tc, mp, 1, 2, true, false);
127 }
128
129 static void
hardlink_rootuser(const atf_tc_t * tc,const char * mp)130 hardlink_rootuser(const atf_tc_t *tc, const char *mp)
131 {
132 hardlink(tc, mp, 1, 0, false, true);
133 }
134
135 static void
hardlink_rootuser_sysctl(const atf_tc_t * tc,const char * mp)136 hardlink_rootuser_sysctl(const atf_tc_t *tc, const char *mp)
137 {
138 hardlink(tc, mp, 1, 0, true, true);
139 }
140
141 ATF_TC_FSAPPLY(hardlink_sameuser, "hardlink same user allowed");
142 ATF_TC_FSAPPLY(hardlink_sameuser_sysctl, "hardlink same user sysctl allowed");
143 ATF_TC_FSAPPLY(hardlink_otheruser, "hardlink other user allowed");
144 ATF_TC_FSAPPLY(hardlink_otheruser_sysctl, "hardlink other user sysctl denied");
145 ATF_TC_FSAPPLY(hardlink_rootuser, "hardlink root user allowed");
146 ATF_TC_FSAPPLY(hardlink_rootuser_sysctl, "hardlink root user sysctl allowed");
147
ATF_TP_ADD_TCS(tp)148 ATF_TP_ADD_TCS(tp)
149 {
150 ATF_TP_FSAPPLY(hardlink_sameuser);
151 ATF_TP_FSAPPLY(hardlink_sameuser_sysctl);
152 ATF_TP_FSAPPLY(hardlink_otheruser);
153 ATF_TP_FSAPPLY(hardlink_otheruser_sysctl);
154 ATF_TP_FSAPPLY(hardlink_rootuser);
155 ATF_TP_FSAPPLY(hardlink_rootuser_sysctl);
156
157 return atf_no_error();
158 }
159