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 * Confirm that a generation number isn't returned by stat() when not running 33 * with privilege. In order to differentiate between a generation of 0 and 34 * a generation not being returned, we have to create a temporary file known 35 * to have a non-0 generation. We try up to MAX_TRIES times, and then give 36 * up, which is non-ideal, but better than not testing for a problem. 37 */ 38 39 #include <sys/stat.h> 40 41 #include <err.h> 42 #include <errno.h> 43 #include <string.h> 44 #include <unistd.h> 45 46 #include "main.h" 47 48 static char fpath[1024]; 49 static int fpath_initialized; 50 51 #define MAX_TRIES 100 52 53 int 54 priv_vfs_generation_setup(int asroot, int injail, struct test *test) 55 { 56 struct stat sb; 57 int i; 58 59 /* 60 * The kernel zeros the generation number field when an unprivileged 61 * user stats a file. In order to distinguish the two cases, we 62 * therefore require a file that we know has a non-zero generation 63 * number. We try up to MAX_TRIES times and otherwise fail. 64 */ 65 for (i = 0; i < MAX_TRIES; i++) { 66 setup_file("priv_vfs_generation_setup: fpath", fpath, 67 UID_ROOT, GID_WHEEL, 0644); 68 if (stat(fpath, &sb) < 0) { 69 warn("priv_vfs_generation_setup: fstat(%s)", fpath); 70 (void)unlink(fpath); 71 return (-1); 72 } 73 if (sb.st_gen != 0) { 74 fpath_initialized = 1; 75 return (0); 76 } 77 } 78 warnx("priv_vfs_generation_setup: unable to create gen file"); 79 return (-1); 80 } 81 82 void 83 priv_vfs_generation(int asroot, int injail, struct test *test) 84 { 85 struct stat sb; 86 int error; 87 88 error = stat(fpath, &sb); 89 if (error < 0) 90 warn("priv_vfs_generation(asroot, injail) stat"); 91 92 if (sb.st_gen == 0) { 93 error = -1; 94 errno = EPERM; 95 } else 96 error = 0; 97 if (asroot && injail) 98 expect("priv_vfs_generation(asroot, injail)", error, -1, 99 EPERM); 100 if (asroot && !injail) 101 expect("priv_vfs_generation(asroot, !injail)", error, 0, 0); 102 if (!asroot && injail) 103 expect("priv_vfs_generation(!asroot, injail)", error, -1, 104 EPERM); 105 if (!asroot && !injail) 106 expect("priv_vfs_generation(!asroot, !injail)", error, -1, 107 EPERM); 108 } 109 110 void 111 priv_vfs_generation_cleanup(int asroot, int injail, struct test *test) 112 { 113 114 if (fpath_initialized) { 115 (void)unlink(fpath); 116 fpath_initialized = 0; 117 } 118 } 119