1 /* $OpenBSD: cfb_enc.c,v 1.14 2021/11/09 18:40:21 bcook Exp $ */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3 * All rights reserved.
4 *
5 * This package is an SSL implementation written
6 * by Eric Young (eay@cryptsoft.com).
7 * The implementation was written so as to conform with Netscapes SSL.
8 *
9 * This library is free for commercial and non-commercial use as long as
10 * the following conditions are aheared to. The following conditions
11 * apply to all code found in this distribution, be it the RC4, RSA,
12 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
13 * included with this distribution is covered by the same copyright terms
14 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
15 *
16 * Copyright remains Eric Young's, and as such any Copyright notices in
17 * the code are not to be removed.
18 * If this package is used in a product, Eric Young should be given attribution
19 * as the author of the parts of the library used.
20 * This can be in the form of a textual message at program startup or
21 * in documentation (online or textual) provided with the package.
22 *
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
25 * are met:
26 * 1. Redistributions of source code must retain the copyright
27 * notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 * notice, this list of conditions and the following disclaimer in the
30 * documentation and/or other materials provided with the distribution.
31 * 3. All advertising materials mentioning features or use of this software
32 * must display the following acknowledgement:
33 * "This product includes cryptographic software written by
34 * Eric Young (eay@cryptsoft.com)"
35 * The word 'cryptographic' can be left out if the rouines from the library
36 * being used are not cryptographic related :-).
37 * 4. If you include any Windows specific code (or a derivative thereof) from
38 * the apps directory (application code) you must include an acknowledgement:
39 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40 *
41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51 * SUCH DAMAGE.
52 *
53 * The licence and distribution terms for any publically available version or
54 * derivative of this code cannot be changed. i.e. this code cannot simply be
55 * copied and put under another distribution licence
56 * [including the GNU Public Licence.]
57 */
58
59 #include "des_locl.h"
60 #include <endian.h>
61
62 /* The input and output are loaded in multiples of 8 bits.
63 * What this means is that if you hame numbits=12 and length=2
64 * the first 12 bits will be retrieved from the first byte and half
65 * the second. The second 12 bits will come from the 3rd and half the 4th
66 * byte.
67 */
68 /* Until Aug 1 2003 this function did not correctly implement CFB-r, so it
69 * will not be compatible with any encryption prior to that date. Ben. */
DES_cfb_encrypt(const unsigned char * in,unsigned char * out,int numbits,long length,DES_key_schedule * schedule,DES_cblock * ivec,int enc)70 void DES_cfb_encrypt(const unsigned char *in, unsigned char *out, int numbits,
71 long length, DES_key_schedule *schedule, DES_cblock *ivec,
72 int enc)
73 {
74 DES_LONG d0,d1,v0,v1;
75 unsigned long l=length;
76 int num=numbits/8,n=(numbits+7)/8,i,rem=numbits%8;
77 DES_LONG ti[2];
78 unsigned char *iv;
79 #if BYTE_ORDER != LITTLE_ENDIAN
80 unsigned char ovec[16];
81 #else
82 unsigned int sh[4];
83 unsigned char *ovec=(unsigned char *)sh;
84 #endif
85
86 if (numbits<=0 || numbits > 64) return;
87 iv = &(*ivec)[0];
88 c2l(iv,v0);
89 c2l(iv,v1);
90 if (enc)
91 {
92 while (l >= (unsigned long)n)
93 {
94 l-=n;
95 ti[0]=v0;
96 ti[1]=v1;
97 DES_encrypt1((DES_LONG *)ti,schedule,DES_ENCRYPT);
98 c2ln(in,d0,d1,n);
99 in+=n;
100 d0^=ti[0];
101 d1^=ti[1];
102 l2cn(d0,d1,out,n);
103 out+=n;
104 /* 30-08-94 - eay - changed because l>>32 and
105 * l<<32 are bad under gcc :-( */
106 if (numbits == 32)
107 { v0=v1; v1=d0; }
108 else if (numbits == 64)
109 { v0=d0; v1=d1; }
110 else
111 {
112 #if BYTE_ORDER != LITTLE_ENDIAN
113 iv=&ovec[0];
114 l2c(v0,iv);
115 l2c(v1,iv);
116 l2c(d0,iv);
117 l2c(d1,iv);
118 #else
119 sh[0]=v0, sh[1]=v1, sh[2]=d0, sh[3]=d1;
120 #endif
121 if (rem==0)
122 memmove(ovec,ovec+num,8);
123 else
124 for(i=0 ; i < 8 ; ++i)
125 ovec[i]=ovec[i+num]<<rem |
126 ovec[i+num+1]>>(8-rem);
127 #if BYTE_ORDER == LITTLE_ENDIAN
128 v0=sh[0], v1=sh[1];
129 #else
130 iv=&ovec[0];
131 c2l(iv,v0);
132 c2l(iv,v1);
133 #endif
134 }
135 }
136 }
137 else
138 {
139 while (l >= (unsigned long)n)
140 {
141 l-=n;
142 ti[0]=v0;
143 ti[1]=v1;
144 DES_encrypt1((DES_LONG *)ti,schedule,DES_ENCRYPT);
145 c2ln(in,d0,d1,n);
146 in+=n;
147 /* 30-08-94 - eay - changed because l>>32 and
148 * l<<32 are bad under gcc :-( */
149 if (numbits == 32)
150 { v0=v1; v1=d0; }
151 else if (numbits == 64)
152 { v0=d0; v1=d1; }
153 else
154 {
155 #if BYTE_ORDER != LITTLE_ENDIAN
156 iv=&ovec[0];
157 l2c(v0,iv);
158 l2c(v1,iv);
159 l2c(d0,iv);
160 l2c(d1,iv);
161 #else
162 sh[0]=v0, sh[1]=v1, sh[2]=d0, sh[3]=d1;
163 #endif
164 if (rem==0)
165 memmove(ovec,ovec+num,8);
166 else
167 for(i=0 ; i < 8 ; ++i)
168 ovec[i]=ovec[i+num]<<rem |
169 ovec[i+num+1]>>(8-rem);
170 #if BYTE_ORDER == LITTLE_ENDIAN
171 v0=sh[0], v1=sh[1];
172 #else
173 iv=&ovec[0];
174 c2l(iv,v0);
175 c2l(iv,v1);
176 #endif
177 }
178 d0^=ti[0];
179 d1^=ti[1];
180 l2cn(d0,d1,out,n);
181 out+=n;
182 }
183 }
184 iv = &(*ivec)[0];
185 l2c(v0,iv);
186 l2c(v1,iv);
187 v0=v1=d0=d1=ti[0]=ti[1]=0;
188 }
189
190