lib/libcrypt/pw_gensalt.c

   1 /*      $NetBSD: pw_gensalt.c,v 1.7 2009/01/18 12:15:27 lukem Exp $     */
   2
   3 /*
   4  * Copyright 1997 Niels Provos <provos@physnet.uni-hamburg.de>
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. All advertising materials mentioning features or use of this software
  16  *    must display the following acknowledgement:
  17  *      This product includes software developed by Niels Provos.
  18  * 4. The name of the author may not be used to endorse or promote products
  19  *    derived from this software without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  22  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  23  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  24  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  26  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  30  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  31  *
  32  * from OpenBSD: pwd_gensalt.c,v 1.9 1998/07/05 21:08:32 provos Exp
  33  */
  34
  35 #include <sys/cdefs.h>
  36 #ifndef lint
  37 __RCSID("$NetBSD: pw_gensalt.c,v 1.7 2009/01/18 12:15:27 lukem Exp $");
  38 #endif /* not lint */
  39
  40 #include <sys/syslimits.h>
  41 #include <sys/types.h>
  42
  43 #include <stdio.h>
  44 #include <stdlib.h>
  45 #include <string.h>
  46 #include <limits.h>
  47 #include <err.h>
  48 #include <grp.h>
  49 #include <pwd.h>
  50 #include <util.h>
  51 #include <time.h>
  52 #include <errno.h>
  53
  54 #include "crypt.h"
  55
  56
  57 static const struct pw_salt {
  58         const char *name;
  59         int (*gensalt)(char *, size_t, const char *);
  60 } salts[] = {
  61         { "old", __gensalt_old },
  62         { "new", __gensalt_new },
  63         { "newsalt", __gensalt_new },
  64         { "md5", __gensalt_md5 },
  65         { "sha1", __gensalt_sha1 },
  66         { "blowfish", __gensalt_blowfish },
  67         { NULL, NULL }
  68 };
  69
  70 static int
  71 getnum(const char *str, size_t *num)
  72 {
  73         char *ep;
  74         unsigned long rv;
  75
  76         if (str == NULL) {
  77                 *num = 0;
  78                 return 0;
  79         }
  80
  81         rv = strtoul(str, &ep, 0);
  82
  83         if (str == ep || *ep) {
  84                 errno = EINVAL;
  85                 return -1;
  86         }
  87
  88         if (errno == ERANGE && rv == ULONG_MAX)
  89                 return -1;
  90         *num = (size_t)rv;
  91         return 0;
  92 }
  93
  94 int
  95 /*ARGSUSED2*/
  96 __gensalt_old(char *salt, size_t saltsiz, const char *option)
  97 {
  98         if (saltsiz < 3) {
  99                 errno = ENOSPC;
 100                 return -1;
 101         }
 102         __crypt_to64(&salt[0], arc4random(), 2);
 103         salt[2] = '\0';
 104         return 0;
 105 }
 106
 107 int
 108 /*ARGSUSED2*/
 109 __gensalt_new(char *salt, size_t saltsiz, const char* option)
 110 {
 111         size_t nrounds;
 112
 113         if (saltsiz < 10) {
 114                 errno = ENOSPC;
 115                 return -1;
 116         }
 117
 118         if (getnum(option, &nrounds) == -1)
 119                 return -1;
 120
 121         /* Check rounds, 24 bit is max */
 122         if (nrounds < 7250)
 123                 nrounds = 7250;
 124         else if (nrounds > 0xffffff)
 125                 nrounds = 0xffffff;
 126         salt[0] = _PASSWORD_EFMT1;
 127         __crypt_to64(&salt[1], (uint32_t)nrounds, 4);
 128         __crypt_to64(&salt[5], arc4random(), 4);
 129         salt[9] = '\0';
 130         return 0;
 131 }
 132
 133 int
 134 /*ARGSUSED2*/
 135 __gensalt_md5(char *salt, size_t saltsiz, const char *option)
 136 {
 137         if (saltsiz < 13) {  /* $1$8salt$\0 */
 138                 errno = ENOSPC;
 139                 return -1;
 140         }
 141         salt[0] = _PASSWORD_NONDES;
 142         salt[1] = '1';
 143         salt[2] = '$';
 144         __crypt_to64(&salt[3], arc4random(), 4);
 145         __crypt_to64(&salt[7], arc4random(), 4);
 146         salt[11] = '$';
 147         salt[12] = '\0';
 148         return 0;
 149 }
 150
 151 int
 152 __gensalt_sha1(char *salt, size_t saltsiz, const char *option)
 153 {
 154         int n;
 155         size_t nrounds;
 156
 157         if (getnum(option, &nrounds) == -1)
 158                 return -1;
 159         n = snprintf(salt, saltsiz, "%s%u$", SHA1_MAGIC,
 160             __crypt_sha1_iterations(nrounds));
 161         /*
 162          * The salt can be up to 64 bytes, but 8
 163          * is considered enough for now.
 164          */
 165         if ((size_t)n + 9 >= saltsiz)
 166                 return 0;
 167         __crypt_to64(&salt[n], arc4random(), 4);
 168         __crypt_to64(&salt[n + 4], arc4random(), 4);
 169         salt[n + 8] = '$';
 170         salt[n + 9] = '\0';
 171         return 0;
 172 }
 173
 174 int
 175 pw_gensalt(char *salt, size_t saltlen, const char *type, const char *option)
 176 {
 177         const struct pw_salt *sp;
 178
 179         for (sp = salts; sp->name; sp++)
 180                 if (strcmp(sp->name, type) == 0)
 181                         return (*sp->gensalt)(salt, saltlen, option);
 182
 183         errno = EINVAL;
 184         return -1;
 185 }