1 /*
2 * Copyright 1995-2022 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 "internal/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 */
DES_cfb_encrypt(const unsigned char * in,unsigned char * out,int numbits,long length,DES_key_schedule * schedule,DES_cblock * ivec,int enc)30 void 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
