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 IBM Corp. 2003
14 *   Author(s): Thomas Spatzier
15 *		Jan Glauber (jan.glauber@de.ibm.com)
16 *
17 * Derived from "crypto/des.c"
18 *   Copyright (c) 1992 Dana L. How.
19 *   Copyright (c) Raimar Falke <rf13@inf.tu-dresden.de>
20 *   Copyright (c) Gisle Sflensminde <gisle@ii.uib.no>
21 *   Copyright (C) 2001 Niels Mvller.
22 *   Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
23 *
24 * This program is free software; you can redistribute it and/or modify
25 * it under the terms of the GNU General Public License as published by
26 * the Free Software Foundation; either version 2 of the License, or
27 * (at your option) any later version.
28 *
29 */
30#include <linux/init.h>
31#include <linux/module.h>
32#include <linux/errno.h>
33#include <linux/crypto.h>
34#include "crypto_des.h"
35
36#define ROR(d,c,o)	((d) = (d) >> (c) | (d) << (o))
37
38static const u8 parity[] = {
39	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,
40	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,
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	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,
44	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,
45	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,
46	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,
47};
48
49/*
50 * RFC2451: Weak key checks SHOULD be performed.
51 */
52int
53crypto_des_check_key(const u8 *key, unsigned int keylen, u32 *flags)
54{
55	u32 n, w;
56
57	n  = parity[key[0]]; n <<= 4;
58	n |= parity[key[1]]; n <<= 4;
59	n |= parity[key[2]]; n <<= 4;
60	n |= parity[key[3]]; n <<= 4;
61	n |= parity[key[4]]; n <<= 4;
62	n |= parity[key[5]]; n <<= 4;
63	n |= parity[key[6]]; n <<= 4;
64	n |= parity[key[7]];
65	w = 0x88888888L;
66
67	if ((*flags & CRYPTO_TFM_REQ_WEAK_KEY)
68	    && !((n - (w >> 3)) & w)) {  /* 1 in 10^10 keys passes this test */
69		if (n < 0x41415151) {
70			if (n < 0x31312121) {
71				if (n < 0x14141515) {
72					/* 01 01 01 01 01 01 01 01 */
73					if (n == 0x11111111) goto weak;
74					/* 01 1F 01 1F 01 0E 01 0E */
75					if (n == 0x13131212) goto weak;
76				} else {
77					/* 01 E0 01 E0 01 F1 01 F1 */
78					if (n == 0x14141515) goto weak;
79					/* 01 FE 01 FE 01 FE 01 FE */
80					if (n == 0x16161616) goto weak;
81				}
82			} else {
83				if (n < 0x34342525) {
84					/* 1F 01 1F 01 0E 01 0E 01 */
85					if (n == 0x31312121) goto weak;
86					/* 1F 1F 1F 1F 0E 0E 0E 0E (?) */
87					if (n == 0x33332222) goto weak;
88				} else {
89					/* 1F E0 1F E0 0E F1 0E F1 */
90					if (n == 0x34342525) goto weak;
91					/* 1F FE 1F FE 0E FE 0E FE */
92					if (n == 0x36362626) goto weak;
93				}
94			}
95		} else {
96			if (n < 0x61616161) {
97				if (n < 0x44445555) {
98					/* E0 01 E0 01 F1 01 F1 01 */
99					if (n == 0x41415151) goto weak;
100					/* E0 1F E0 1F F1 0E F1 0E */
101					if (n == 0x43435252) goto weak;
102				} else {
103					/* E0 E0 E0 E0 F1 F1 F1 F1 (?) */
104					if (n == 0x44445555) goto weak;
105					/* E0 FE E0 FE F1 FE F1 FE */
106					if (n == 0x46465656) goto weak;
107				}
108			} else {
109				if (n < 0x64646565) {
110					/* FE 01 FE 01 FE 01 FE 01 */
111					if (n == 0x61616161) goto weak;
112					/* FE 1F FE 1F FE 0E FE 0E */
113					if (n == 0x63636262) goto weak;
114				} else {
115					/* FE E0 FE E0 FE F1 FE F1 */
116					if (n == 0x64646565) goto weak;
117					/* FE FE FE FE FE FE FE FE */
118					if (n == 0x66666666) goto weak;
119				}
120			}
121		}
122	}
123	return 0;
124weak:
125	*flags |= CRYPTO_TFM_RES_WEAK_KEY;
126	return -EINVAL;
127}
128
129EXPORT_SYMBOL(crypto_des_check_key);
130
131MODULE_LICENSE("GPL");
132MODULE_DESCRIPTION("Key Check function for DES &  DES3 Cipher Algorithms");
133