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 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 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 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 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 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 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 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"); 147 148 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