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 "e_os.h"
17#include "des_local.h"
18#include <assert.h>
19
20/*
21 * The input and output are loaded in multiples of 8 bits. What this means is
22 * that if you hame numbits=12 and length=2 the first 12 bits will be
23 * retrieved from the first byte and half the second.  The second 12 bits
24 * will come from the 3rd and half the 4th byte.
25 */
26/*
27 * Until Aug 1 2003 this function did not correctly implement CFB-r, so it
28 * will not be compatible with any encryption prior to that date. Ben.
29 */
30void DES_cfb_encrypt(const unsigned char *in, unsigned char *out, int numbits,
31                     long length, DES_key_schedule *schedule,
32                     DES_cblock *ivec, int enc)
33{
34    register DES_LONG d0, d1, v0, v1;
35    register unsigned long l = length;
36    register int num = numbits / 8, n = (numbits + 7) / 8, i, rem =
37        numbits % 8;
38    DES_LONG ti[2];
39    unsigned char *iv;
40#ifndef L_ENDIAN
41    unsigned char ovec[16];
42#else
43    unsigned int sh[4];
44    unsigned char *ovec = (unsigned char *)sh;
45
46    /* I kind of count that compiler optimizes away this assertion, */
47    assert(sizeof(sh[0]) == 4); /* as this holds true for all, */
48    /* but 16-bit platforms...      */
49
50#endif
51
52    if (numbits <= 0 || numbits > 64)
53        return;
54    iv = &(*ivec)[0];
55    c2l(iv, v0);
56    c2l(iv, v1);
57    if (enc) {
58        while (l >= (unsigned long)n) {
59            l -= n;
60            ti[0] = v0;
61            ti[1] = v1;
62            DES_encrypt1((DES_LONG *)ti, schedule, DES_ENCRYPT);
63            c2ln(in, d0, d1, n);
64            in += n;
65            d0 ^= ti[0];
66            d1 ^= ti[1];
67            l2cn(d0, d1, out, n);
68            out += n;
69            /*
70             * 30-08-94 - eay - changed because l>>32 and l<<32 are bad under
71             * gcc :-(
72             */
73            if (numbits == 32) {
74                v0 = v1;
75                v1 = d0;
76            } else if (numbits == 64) {
77                v0 = d0;
78                v1 = d1;
79            } else {
80#ifndef L_ENDIAN
81                iv = &ovec[0];
82                l2c(v0, iv);
83                l2c(v1, iv);
84                l2c(d0, iv);
85                l2c(d1, iv);
86#else
87                sh[0] = v0, sh[1] = v1, sh[2] = d0, sh[3] = d1;
88#endif
89                if (rem == 0)
90                    memmove(ovec, ovec + num, 8);
91                else
92                    for (i = 0; i < 8; ++i)
93                        ovec[i] = ovec[i + num] << rem |
94                            ovec[i + num + 1] >> (8 - rem);
95#ifdef L_ENDIAN
96                v0 = sh[0], v1 = sh[1];
97#else
98                iv = &ovec[0];
99                c2l(iv, v0);
100                c2l(iv, v1);
101#endif
102            }
103        }
104    } else {
105        while (l >= (unsigned long)n) {
106            l -= n;
107            ti[0] = v0;
108            ti[1] = v1;
109            DES_encrypt1((DES_LONG *)ti, schedule, DES_ENCRYPT);
110            c2ln(in, d0, d1, n);
111            in += n;
112            /*
113             * 30-08-94 - eay - changed because l>>32 and l<<32 are bad under
114             * gcc :-(
115             */
116            if (numbits == 32) {
117                v0 = v1;
118                v1 = d0;
119            } else if (numbits == 64) {
120                v0 = d0;
121                v1 = d1;
122            } else {
123#ifndef L_ENDIAN
124                iv = &ovec[0];
125                l2c(v0, iv);
126                l2c(v1, iv);
127                l2c(d0, iv);
128                l2c(d1, iv);
129#else
130                sh[0] = v0, sh[1] = v1, sh[2] = d0, sh[3] = d1;
131#endif
132                if (rem == 0)
133                    memmove(ovec, ovec + num, 8);
134                else
135                    for (i = 0; i < 8; ++i)
136                        ovec[i] = ovec[i + num] << rem |
137                            ovec[i + num + 1] >> (8 - rem);
138#ifdef L_ENDIAN
139                v0 = sh[0], v1 = sh[1];
140#else
141                iv = &ovec[0];
142                c2l(iv, v0);
143                c2l(iv, v1);
144#endif
145            }
146            d0 ^= ti[0];
147            d1 ^= ti[1];
148            l2cn(d0, d1, out, n);
149            out += n;
150        }
151    }
152    iv = &(*ivec)[0];
153    l2c(v0, iv);
154    l2c(v1, iv);
155    v0 = v1 = d0 = d1 = ti[0] = ti[1] = 0;
156}
157