xref: /openssl/crypto/des/cfb64ede.c (revision 33388b44)
1 /*
2  * Copyright 1995-2020 The OpenSSL Project Authors. All Rights Reserved.
3  *
4  * Licensed under the Apache License 2.0 (the "License").  You may not use
5  * this file except in compliance with the License.  You can obtain a copy
6  * in the file LICENSE in the source distribution or at
7  * https://www.openssl.org/source/license.html
8  */
9 
10 /*
11  * DES low level APIs are deprecated for public use, but still ok for internal
12  * use.
13  */
14 #include "internal/deprecated.h"
15 
16 #include "des_local.h"
17 
18 /*
19  * The input and output encrypted as though 64bit cfb mode is being used.
20  * The extra state information to record how much of the 64bit block we have
21  * used is contained in *num;
22  */
23 
DES_ede3_cfb64_encrypt(const unsigned char * in,unsigned char * out,long length,DES_key_schedule * ks1,DES_key_schedule * ks2,DES_key_schedule * ks3,DES_cblock * ivec,int * num,int enc)24 void DES_ede3_cfb64_encrypt(const unsigned char *in, unsigned char *out,
25                             long length, DES_key_schedule *ks1,
26                             DES_key_schedule *ks2, DES_key_schedule *ks3,
27                             DES_cblock *ivec, int *num, int enc)
28 {
29     register DES_LONG v0, v1;
30     register long l = length;
31     register int n = *num;
32     DES_LONG ti[2];
33     unsigned char *iv, c, cc;
34 
35     iv = &(*ivec)[0];
36     if (enc) {
37         while (l--) {
38             if (n == 0) {
39                 c2l(iv, v0);
40                 c2l(iv, v1);
41 
42                 ti[0] = v0;
43                 ti[1] = v1;
44                 DES_encrypt3(ti, ks1, ks2, ks3);
45                 v0 = ti[0];
46                 v1 = ti[1];
47 
48                 iv = &(*ivec)[0];
49                 l2c(v0, iv);
50                 l2c(v1, iv);
51                 iv = &(*ivec)[0];
52             }
53             c = *(in++) ^ iv[n];
54             *(out++) = c;
55             iv[n] = c;
56             n = (n + 1) & 0x07;
57         }
58     } else {
59         while (l--) {
60             if (n == 0) {
61                 c2l(iv, v0);
62                 c2l(iv, v1);
63 
64                 ti[0] = v0;
65                 ti[1] = v1;
66                 DES_encrypt3(ti, ks1, ks2, ks3);
67                 v0 = ti[0];
68                 v1 = ti[1];
69 
70                 iv = &(*ivec)[0];
71                 l2c(v0, iv);
72                 l2c(v1, iv);
73                 iv = &(*ivec)[0];
74             }
75             cc = *(in++);
76             c = iv[n];
77             iv[n] = cc;
78             *(out++) = c ^ cc;
79             n = (n + 1) & 0x07;
80         }
81     }
82     v0 = v1 = ti[0] = ti[1] = c = cc = 0;
83     *num = n;
84 }
85 
86 /*
87  * This is compatible with the single key CFB-r for DES, even thought that's
88  * not what EVP needs.
89  */
90 
DES_ede3_cfb_encrypt(const unsigned char * in,unsigned char * out,int numbits,long length,DES_key_schedule * ks1,DES_key_schedule * ks2,DES_key_schedule * ks3,DES_cblock * ivec,int enc)91 void DES_ede3_cfb_encrypt(const unsigned char *in, unsigned char *out,
92                           int numbits, long length, DES_key_schedule *ks1,
93                           DES_key_schedule *ks2, DES_key_schedule *ks3,
94                           DES_cblock *ivec, int enc)
95 {
96     register DES_LONG d0, d1, v0, v1;
97     register unsigned long l = length, n = ((unsigned int)numbits + 7) / 8;
98     register int num = numbits, i;
99     DES_LONG ti[2];
100     unsigned char *iv;
101     unsigned char ovec[16];
102 
103     if (num > 64)
104         return;
105     iv = &(*ivec)[0];
106     c2l(iv, v0);
107     c2l(iv, v1);
108     if (enc) {
109         while (l >= n) {
110             l -= n;
111             ti[0] = v0;
112             ti[1] = v1;
113             DES_encrypt3(ti, ks1, ks2, ks3);
114             c2ln(in, d0, d1, n);
115             in += n;
116             d0 ^= ti[0];
117             d1 ^= ti[1];
118             l2cn(d0, d1, out, n);
119             out += n;
120             /*
121              * 30-08-94 - eay - changed because l>>32 and l<<32 are bad under
122              * gcc :-(
123              */
124             if (num == 32) {
125                 v0 = v1;
126                 v1 = d0;
127             } else if (num == 64) {
128                 v0 = d0;
129                 v1 = d1;
130             } else {
131                 iv = &ovec[0];
132                 l2c(v0, iv);
133                 l2c(v1, iv);
134                 l2c(d0, iv);
135                 l2c(d1, iv);
136                 /* shift ovec left most of the bits... */
137                 memmove(ovec, ovec + num / 8, 8 + (num % 8 ? 1 : 0));
138                 /* now the remaining bits */
139                 if (num % 8 != 0)
140                     for (i = 0; i < 8; ++i) {
141                         ovec[i] <<= num % 8;
142                         ovec[i] |= ovec[i + 1] >> (8 - num % 8);
143                     }
144                 iv = &ovec[0];
145                 c2l(iv, v0);
146                 c2l(iv, v1);
147             }
148         }
149     } else {
150         while (l >= n) {
151             l -= n;
152             ti[0] = v0;
153             ti[1] = v1;
154             DES_encrypt3(ti, ks1, ks2, ks3);
155             c2ln(in, d0, d1, n);
156             in += n;
157             /*
158              * 30-08-94 - eay - changed because l>>32 and l<<32 are bad under
159              * gcc :-(
160              */
161             if (num == 32) {
162                 v0 = v1;
163                 v1 = d0;
164             } else if (num == 64) {
165                 v0 = d0;
166                 v1 = d1;
167             } else {
168                 iv = &ovec[0];
169                 l2c(v0, iv);
170                 l2c(v1, iv);
171                 l2c(d0, iv);
172                 l2c(d1, iv);
173                 /* shift ovec left most of the bits... */
174                 memmove(ovec, ovec + num / 8, 8 + (num % 8 ? 1 : 0));
175                 /* now the remaining bits */
176                 if (num % 8 != 0)
177                     for (i = 0; i < 8; ++i) {
178                         ovec[i] <<= num % 8;
179                         ovec[i] |= ovec[i + 1] >> (8 - num % 8);
180                     }
181                 iv = &ovec[0];
182                 c2l(iv, v0);
183                 c2l(iv, v1);
184             }
185             d0 ^= ti[0];
186             d1 ^= ti[1];
187             l2cn(d0, d1, out, n);
188             out += n;
189         }
190     }
191     iv = &(*ivec)[0];
192     l2c(v0, iv);
193     l2c(v1, iv);
194     v0 = v1 = d0 = d1 = ti[0] = ti[1] = 0;
195 }
196