1 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
2 * All rights reserved.
3 *
4 * This package is an SSL implementation written
5 * by Eric Young (eay@cryptsoft.com).
6 * The implementation was written so as to conform with Netscapes SSL.
7 *
8 * This library is free for commercial and non-commercial use as long as
9 * the following conditions are aheared to. The following conditions
10 * apply to all code found in this distribution, be it the RC4, RSA,
11 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
12 * included with this distribution is covered by the same copyright terms
13 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
14 *
15 * Copyright remains Eric Young's, and as such any Copyright notices in
16 * the code are not to be removed.
17 * If this package is used in a product, Eric Young should be given attribution
18 * as the author of the parts of the library used.
19 * This can be in the form of a textual message at program startup or
20 * in documentation (online or textual) provided with the package.
21 *
22 * Redistribution and use in source and binary forms, with or without
23 * modification, are permitted provided that the following conditions
24 * are met:
25 * 1. Redistributions of source code must retain the copyright
26 * notice, this list of conditions and the following disclaimer.
27 * 2. Redistributions in binary form must reproduce the above copyright
28 * notice, this list of conditions and the following disclaimer in the
29 * documentation and/or other materials provided with the distribution.
30 * 3. All advertising materials mentioning features or use of this software
31 * must display the following acknowledgement:
32 * "This product includes cryptographic software written by
33 * Eric Young (eay@cryptsoft.com)"
34 * The word 'cryptographic' can be left out if the rouines from the library
35 * being used are not cryptographic related :-).
36 * 4. If you include any Windows specific code (or a derivative thereof) from
37 * the apps directory (application code) you must include an acknowledgement:
38 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
39 *
40 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
41 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
44 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50 * SUCH DAMAGE.
51 *
52 * The licence and distribution terms for any publically available version or
53 * derivative of this code cannot be changed. i.e. this code cannot simply be
54 * copied and put under another distribution licence
55 * [including the GNU Public Licence.] */
56
57 #include <openssl/rc4.h>
58
59 #if defined(OPENSSL_NO_ASM) || \
60 (!defined(OPENSSL_X86_64) && !defined(OPENSSL_X86))
61
62 #if defined(OPENSSL_64_BIT)
63 #define RC4_CHUNK uint64_t
64 #elif defined(OPENSSL_32_BIT)
65 #define RC4_CHUNK uint32_t
66 #else
67 #error "Unknown word size"
68 #endif
69
70
71 /* RC4 as implemented from a posting from
72 * Newsgroups: sci.crypt
73 * From: sterndark@netcom.com (David Sterndark)
74 * Subject: RC4 Algorithm revealed.
75 * Message-ID: <sternCvKL4B.Hyy@netcom.com>
76 * Date: Wed, 14 Sep 1994 06:35:31 GMT */
77
RC4(RC4_KEY * key,size_t len,const uint8_t * in,uint8_t * out)78 void RC4(RC4_KEY *key, size_t len, const uint8_t *in, uint8_t *out) {
79 uint32_t *d;
80 uint32_t x, y, tx, ty;
81 size_t i;
82
83 x = key->x;
84 y = key->y;
85 d = key->data;
86
87 #define RC4_STEP \
88 (x = (x + 1) & 0xff, tx = d[x], y = (tx + y) & 0xff, ty = d[y], d[y] = tx, \
89 d[x] = ty, (RC4_CHUNK)d[(tx + ty) & 0xff])
90
91 if ((((size_t)in & (sizeof(RC4_CHUNK) - 1)) |
92 ((size_t)out & (sizeof(RC4_CHUNK) - 1))) == 0) {
93 RC4_CHUNK ichunk, otp;
94 const union {
95 long one;
96 char little;
97 } is_endian = {1};
98
99 /* I reckon we can afford to implement both endian
100 * cases and to decide which way to take at run-time
101 * because the machine code appears to be very compact
102 * and redundant 1-2KB is perfectly tolerable (i.e.
103 * in case the compiler fails to eliminate it:-). By
104 * suggestion from Terrel Larson <terr@terralogic.net>
105 * who also stands for the is_endian union:-)
106 *
107 * Special notes.
108 *
109 * - is_endian is declared automatic as doing otherwise
110 * (declaring static) prevents gcc from eliminating
111 * the redundant code;
112 * - compilers (those I've tried) don't seem to have
113 * problems eliminating either the operators guarded
114 * by "if (sizeof(RC4_CHUNK)==8)" or the condition
115 * expressions themselves so I've got 'em to replace
116 * corresponding #ifdefs from the previous version;
117 * - I chose to let the redundant switch cases when
118 * sizeof(RC4_CHUNK)!=8 be (were also #ifdefed
119 * before);
120 * - in case you wonder "&(sizeof(RC4_CHUNK)*8-1)" in
121 * [LB]ESHFT guards against "shift is out of range"
122 * warnings when sizeof(RC4_CHUNK)!=8
123 *
124 * <appro@fy.chalmers.se> */
125 if (!is_endian.little) { /* BIG-ENDIAN CASE */
126 #define BESHFT(c) \
127 (((sizeof(RC4_CHUNK) - (c) - 1) * 8) & (sizeof(RC4_CHUNK) * 8 - 1))
128 for (; len & (0 - sizeof(RC4_CHUNK)); len -= sizeof(RC4_CHUNK)) {
129 ichunk = *(RC4_CHUNK *)in;
130 otp = RC4_STEP << BESHFT(0);
131 otp |= RC4_STEP << BESHFT(1);
132 otp |= RC4_STEP << BESHFT(2);
133 otp |= RC4_STEP << BESHFT(3);
134 #if defined(OPENSSL_64_BIT)
135 otp |= RC4_STEP << BESHFT(4);
136 otp |= RC4_STEP << BESHFT(5);
137 otp |= RC4_STEP << BESHFT(6);
138 otp |= RC4_STEP << BESHFT(7);
139 #endif
140 *(RC4_CHUNK *)out = otp ^ ichunk;
141 in += sizeof(RC4_CHUNK);
142 out += sizeof(RC4_CHUNK);
143 }
144 } else { /* LITTLE-ENDIAN CASE */
145 #define LESHFT(c) (((c) * 8) & (sizeof(RC4_CHUNK) * 8 - 1))
146 for (; len & (0 - sizeof(RC4_CHUNK)); len -= sizeof(RC4_CHUNK)) {
147 ichunk = *(RC4_CHUNK *)in;
148 otp = RC4_STEP;
149 otp |= RC4_STEP << 8;
150 otp |= RC4_STEP << 16;
151 otp |= RC4_STEP << 24;
152 #if defined(OPENSSL_64_BIT)
153 otp |= RC4_STEP << LESHFT(4);
154 otp |= RC4_STEP << LESHFT(5);
155 otp |= RC4_STEP << LESHFT(6);
156 otp |= RC4_STEP << LESHFT(7);
157 #endif
158 *(RC4_CHUNK *)out = otp ^ ichunk;
159 in += sizeof(RC4_CHUNK);
160 out += sizeof(RC4_CHUNK);
161 }
162 }
163 }
164 #define LOOP(in, out) \
165 x = ((x + 1) & 0xff); \
166 tx = d[x]; \
167 y = (tx + y) & 0xff; \
168 d[x] = ty = d[y]; \
169 d[y] = tx; \
170 (out) = d[(tx + ty) & 0xff] ^ (in);
171
172 #ifndef RC4_INDEX
173 #define RC4_LOOP(a, b, i) LOOP(*((a)++), *((b)++))
174 #else
175 #define RC4_LOOP(a, b, i) LOOP(a[i], b[i])
176 #endif
177
178 i = len >> 3;
179 if (i) {
180 for (;;) {
181 RC4_LOOP(in, out, 0);
182 RC4_LOOP(in, out, 1);
183 RC4_LOOP(in, out, 2);
184 RC4_LOOP(in, out, 3);
185 RC4_LOOP(in, out, 4);
186 RC4_LOOP(in, out, 5);
187 RC4_LOOP(in, out, 6);
188 RC4_LOOP(in, out, 7);
189 #ifdef RC4_INDEX
190 in += 8;
191 out += 8;
192 #endif
193 if (--i == 0) {
194 break;
195 }
196 }
197 }
198 i = len & 0x07;
199 if (i) {
200 for (;;) {
201 RC4_LOOP(in, out, 0);
202 if (--i == 0) {
203 break;
204 }
205 RC4_LOOP(in, out, 1);
206 if (--i == 0) {
207 break;
208 }
209 RC4_LOOP(in, out, 2);
210 if (--i == 0) {
211 break;
212 }
213 RC4_LOOP(in, out, 3);
214 if (--i == 0) {
215 break;
216 }
217 RC4_LOOP(in, out, 4);
218 if (--i == 0) {
219 break;
220 }
221 RC4_LOOP(in, out, 5);
222 if (--i == 0) {
223 break;
224 }
225 RC4_LOOP(in, out, 6);
226 if (--i == 0) {
227 break;
228 }
229 }
230 }
231 key->x = x;
232 key->y = y;
233 }
234
RC4_set_key(RC4_KEY * rc4key,unsigned len,const uint8_t * key)235 void RC4_set_key(RC4_KEY *rc4key, unsigned len, const uint8_t *key) {
236 uint32_t tmp;
237 unsigned i, id1, id2;
238 uint32_t *d;
239
240 d = &rc4key->data[0];
241 rc4key->x = 0;
242 rc4key->y = 0;
243 id1 = id2 = 0;
244
245 #define SK_LOOP(d, n) \
246 { \
247 tmp = d[(n)]; \
248 id2 = (key[id1] + tmp + id2) & 0xff; \
249 if (++id1 == len) \
250 id1 = 0; \
251 d[(n)] = d[id2]; \
252 d[id2] = tmp; \
253 }
254
255 for (i = 0; i < 256; i++) {
256 d[i] = i;
257 }
258 for (i = 0; i < 256; i += 4) {
259 SK_LOOP(d, i + 0);
260 SK_LOOP(d, i + 1);
261 SK_LOOP(d, i + 2);
262 SK_LOOP(d, i + 3);
263 }
264 }
265
266 #else
267
268 /* In this case several functions are provided by asm code. However, one cannot
269 * control asm symbol visibility with command line flags and such so they are
270 * always hidden and wrapped by these C functions, which can be so
271 * controlled. */
272
273 void asm_RC4(RC4_KEY *key, size_t len, const uint8_t *in, uint8_t *out);
RC4(RC4_KEY * key,size_t len,const uint8_t * in,uint8_t * out)274 void RC4(RC4_KEY *key, size_t len, const uint8_t *in, uint8_t *out) {
275 asm_RC4(key, len, in, out);
276 }
277
278 void asm_RC4_set_key(RC4_KEY *rc4key, unsigned len, const uint8_t *key);
RC4_set_key(RC4_KEY * rc4key,unsigned len,const uint8_t * key)279 void RC4_set_key(RC4_KEY *rc4key, unsigned len, const uint8_t *key) {
280 asm_RC4_set_key(rc4key, len, key);
281 }
282
283 #endif /* OPENSSL_NO_ASM || (!OPENSSL_X86_64 && !OPENSSL_X86) */
284