tools/regression/priv/priv_vfs_generation.c

   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 }