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 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 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 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 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 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 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