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 * $FreeBSD$ 31 */ 32 33 /* 34 * Confirm that a generation number isn't returned by stat() when not running 35 * with privilege. In order to differentiate between a generation of 0 and 36 * a generation not being returned, we have to create a temporary file known 37 * to have a non-0 generation. We try up to MAX_TRIES times, and then give 38 * up, which is non-ideal, but better than not testing for a problem. 39 */ 40 41 #include <sys/stat.h> 42 43 #include <err.h> 44 #include <errno.h> 45 #include <string.h> 46 #include <unistd.h> 47 48 #include "main.h" 49 50 static char fpath[1024]; 51 static int fpath_initialized; 52 53 #define MAX_TRIES 100 54 55 int 56 priv_vfs_generation_setup(int asroot, int injail, struct test *test) 57 { 58 struct stat sb; 59 int i; 60 61 /* 62 * The kernel zeros the generation number field when an unprivileged 63 * user stats a file. In order to distinguish the two cases, we 64 * therefore require a file that we know has a non-zero generation 65 * number. We try up to MAX_TRIES times and otherwise fail. 66 */ 67 for (i = 0; i < MAX_TRIES; i++) { 68 setup_file("priv_vfs_generation_setup: fpath", fpath, 69 UID_ROOT, GID_WHEEL, 0644); 70 if (stat(fpath, &sb) < 0) { 71 warn("priv_vfs_generation_setup: fstat(%s)", fpath); 72 (void)unlink(fpath); 73 return (-1); 74 } 75 if (sb.st_gen != 0) { 76 fpath_initialized = 1; 77 return (0); 78 } 79 } 80 warnx("priv_vfs_generation_setup: unable to create gen file"); 81 return (-1); 82 } 83 84 void 85 priv_vfs_generation(int asroot, int injail, struct test *test) 86 { 87 struct stat sb; 88 int error; 89 90 error = stat(fpath, &sb); 91 if (error < 0) 92 warn("priv_vfs_generation(asroot, injail) stat"); 93 94 if (sb.st_gen == 0) { 95 error = -1; 96 errno = EPERM; 97 } else 98 error = 0; 99 if (asroot && injail) 100 expect("priv_vfs_generation(asroot, injail)", error, -1, 101 EPERM); 102 if (asroot && !injail) 103 expect("priv_vfs_generation(asroot, !injail)", error, 0, 0); 104 if (!asroot && injail) 105 expect("priv_vfs_generation(!asroot, injail)", error, -1, 106 EPERM); 107 if (!asroot && !injail) 108 expect("priv_vfs_generation(!asroot, !injail)", error, -1, 109 EPERM); 110 } 111 112 void 113 priv_vfs_generation_cleanup(int asroot, int injail, struct test *test) 114 { 115 116 if (fpath_initialized) { 117 (void)unlink(fpath); 118 fpath_initialized = 0; 119 } 120 } 121