arch/s390/crypto/des_check_key.c

   1 /*
   2  * Cryptographic API.
   3  *
   4  * Function for checking keys for the DES and Tripple DES Encryption
   5  * algorithms.
   6  *
   7  * Originally released as descore by Dana L. How <how@isl.stanford.edu>.
   8  * Modified by Raimar Falke <rf13@inf.tu-dresden.de> for the Linux-Kernel.
   9  * Derived from Cryptoapi and Nettle implementations, adapted for in-place
  10  * scatterlist interface.  Changed LGPL to GPL per section 3 of the LGPL.
  11  *
  12  * s390 Version:
  13  *   Copyright (C) 2003 IBM Deutschland GmbH, IBM Corporation
  14  *   Author(s): Thomas Spatzier (tspat@de.ibm.com)
  15  *
  16  * Derived from "crypto/des.c"
  17  *   Copyright (c) 1992 Dana L. How.
  18  *   Copyright (c) Raimar Falke <rf13@inf.tu-dresden.de>
  19  *   Copyright (c) Gisle Sflensminde <gisle@ii.uib.no>
  20  *   Copyright (C) 2001 Niels Mvller.
  21  *   Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
  22  *
  23  * This program is free software; you can redistribute it and/or modify
  24  * it under the terms of the GNU General Public License as published by
  25  * the Free Software Foundation; either version 2 of the License, or
  26  * (at your option) any later version.
  27  *
  28  */
  29 #include <linux/init.h>
  30 #include <linux/module.h>
  31 #include <linux/errno.h>
  32 #include <linux/crypto.h>
  33
  34 #define ROR(d,c,o)      ((d) = (d) >> (c) | (d) << (o))
  35
  36 static const u8 parity[] = {
  37         8,1,0,8,0,8,8,0,0,8,8,0,8,0,2,8,0,8,8,0,8,0,0,8,8,0,0,8,0,8,8,3,
  38         0,8,8,0,8,0,0,8,8,0,0,8,0,8,8,0,8,0,0,8,0,8,8,0,0,8,8,0,8,0,0,8,
  39         0,8,8,0,8,0,0,8,8,0,0,8,0,8,8,0,8,0,0,8,0,8,8,0,0,8,8,0,8,0,0,8,
  40         8,0,0,8,0,8,8,0,0,8,8,0,8,0,0,8,0,8,8,0,8,0,0,8,8,0,0,8,0,8,8,0,
  41         0,8,8,0,8,0,0,8,8,0,0,8,0,8,8,0,8,0,0,8,0,8,8,0,0,8,8,0,8,0,0,8,
  42         8,0,0,8,0,8,8,0,0,8,8,0,8,0,0,8,0,8,8,0,8,0,0,8,8,0,0,8,0,8,8,0,
  43         8,0,0,8,0,8,8,0,0,8,8,0,8,0,0,8,0,8,8,0,8,0,0,8,8,0,0,8,0,8,8,0,
  44         4,8,8,0,8,0,0,8,8,0,0,8,0,8,8,0,8,5,0,8,0,8,8,0,0,8,8,0,8,0,6,8,
  45 };
  46
  47 /*
  48  * RFC2451: Weak key checks SHOULD be performed.
  49  */
  50 int
  51 crypto_des_check_key(const u8 *key, unsigned int keylen, u32 *flags)
  52 {
  53         u32 n, w;
  54
  55         n  = parity[key[0]]; n <<= 4;
  56         n |= parity[key[1]]; n <<= 4;
  57         n |= parity[key[2]]; n <<= 4;
  58         n |= parity[key[3]]; n <<= 4;
  59         n |= parity[key[4]]; n <<= 4;
  60         n |= parity[key[5]]; n <<= 4;
  61         n |= parity[key[6]]; n <<= 4;
  62         n |= parity[key[7]];
  63         w = 0x88888888L;
  64
  65         if ((*flags & CRYPTO_TFM_REQ_WEAK_KEY)
  66             && !((n - (w >> 3)) & w)) {  /* 1 in 10^10 keys passes this test */
  67                 if (n < 0x41415151) {
  68                         if (n < 0x31312121) {
  69                                 if (n < 0x14141515) {
  70                                         /* 01 01 01 01 01 01 01 01 */
  71                                         if (n == 0x11111111) goto weak;
  72                                         /* 01 1F 01 1F 01 0E 01 0E */
  73                                         if (n == 0x13131212) goto weak;
  74                                 } else {
  75                                         /* 01 E0 01 E0 01 F1 01 F1 */
  76                                         if (n == 0x14141515) goto weak;
  77                                         /* 01 FE 01 FE 01 FE 01 FE */
  78                                         if (n == 0x16161616) goto weak;
  79                                 }
  80                         } else {
  81                                 if (n < 0x34342525) {
  82                                         /* 1F 01 1F 01 0E 01 0E 01 */
  83                                         if (n == 0x31312121) goto weak;
  84                                         /* 1F 1F 1F 1F 0E 0E 0E 0E (?) */
  85                                         if (n == 0x33332222) goto weak;
  86                                 } else {
  87                                         /* 1F E0 1F E0 0E F1 0E F1 */
  88                                         if (n == 0x34342525) goto weak;
  89                                         /* 1F FE 1F FE 0E FE 0E FE */
  90                                         if (n == 0x36362626) goto weak;
  91                                 }
  92                         }
  93                 } else {
  94                         if (n < 0x61616161) {
  95                                 if (n < 0x44445555) {
  96                                         /* E0 01 E0 01 F1 01 F1 01 */
  97                                         if (n == 0x41415151) goto weak;
  98                                         /* E0 1F E0 1F F1 0E F1 0E */
  99                                         if (n == 0x43435252) goto weak;
 100                                 } else {
 101                                         /* E0 E0 E0 E0 F1 F1 F1 F1 (?) */
 102                                         if (n == 0x44445555) goto weak;
 103                                         /* E0 FE E0 FE F1 FE F1 FE */
 104                                         if (n == 0x46465656) goto weak;
 105                                 }
 106                         } else {
 107                                 if (n < 0x64646565) {
 108                                         /* FE 01 FE 01 FE 01 FE 01 */
 109                                         if (n == 0x61616161) goto weak;
 110                                         /* FE 1F FE 1F FE 0E FE 0E */
 111                                         if (n == 0x63636262) goto weak;
 112                                 } else {
 113                                         /* FE E0 FE E0 FE F1 FE F1 */
 114                                         if (n == 0x64646565) goto weak;
 115                                         /* FE FE FE FE FE FE FE FE */
 116                                         if (n == 0x66666666) goto weak;
 117                                 }
 118                         }
 119                 }
 120         }
 121         return 0;
 122 weak:
 123         *flags |= CRYPTO_TFM_RES_WEAK_KEY;
 124         return -EINVAL;
 125 }
 126
 127 EXPORT_SYMBOL(crypto_des_check_key);
 128
 129 MODULE_LICENSE("GPL");
 130 MODULE_DESCRIPTION("Key Check function for DES &  DES3 Cipher Algorithms");