D-Bus: dbus-sha.c Source File

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dbus-sha.c
1/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
2/* dbus-sha.c SHA-1 implementation
3 *
4 * Copyright (C) 2003 Red Hat Inc.
5 * Copyright (C) 1995 A. M. Kuchling
6 *
7 * Licensed under the Academic Free License version 2.1
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 *
23 */
24
25#include <config.h>
26#include "dbus-internals.h"
27#include "dbus-sha.h"
28#include "dbus-marshal-basic.h" /* for byteswap routines */
29#include <string.h>
30
31/* The following comments have the history of where this code
32 * comes from. I actually copied it from GNet in GNOME CVS.
33 * - hp@redhat.com
34 */
35
36/*
37 * sha.h : Implementation of the Secure Hash Algorithm
38 *
39 * Part of the Python Cryptography Toolkit, version 1.0.0
40 *
41 * Copyright (C) 1995, A.M. Kuchling
42 *
43 * Distribute and use freely; there are no restrictions on further
44 * dissemination and usage except those imposed by the laws of your
45 * country of residence.
46 *
47 */
48
49/* SHA: NIST's Secure Hash Algorithm */
50
51/* Based on SHA code originally posted to sci.crypt by Peter Gutmann
52 in message <30ajo5$oe8@ccu2.auckland.ac.nz>.
53 Modified to test for endianness on creation of SHA objects by AMK.
54 Also, the original specification of SHA was found to have a weakness
55 by NSA/NIST. This code implements the fixed version of SHA.
56*/
57
58/* Here's the first paragraph of Peter Gutmann's posting:
59
60The following is my SHA (FIPS 180) code updated to allow use of the "fixed"
61SHA, thanks to Jim Gillogly and an anonymous contributor for the information on
62what's changed in the new version. The fix is a simple change which involves
63adding a single rotate in the initial expansion function. It is unknown
64whether this is an optimal solution to the problem which was discovered in the
65SHA or whether it's simply a bandaid which fixes the problem with a minimum of
66effort (for example the reengineering of a great many Capstone chips).
67*/
68
88#ifndef DOXYGEN_SHOULD_SKIP_THIS
89
90/* The SHA block size and message digest sizes, in bytes */
91
92#define SHA_DATASIZE 64
93#define SHA_DIGESTSIZE 20
94
95/* The SHA f()-functions. The f1 and f3 functions can be optimized to
96 save one boolean operation each - thanks to Rich Schroeppel,
97 rcs@cs.arizona.edu for discovering this */
98
99/*#define f1(x,y,z) ( ( x & y ) | ( ~x & z ) ) // Rounds 0-19 */
100#define f1(x,y,z) ( z ^ ( x & ( y ^ z ) ) ) /* Rounds 0-19 */
101#define f2(x,y,z) ( x ^ y ^ z ) /* Rounds 20-39 */
102/*#define f3(x,y,z) ( ( x & y ) | ( x & z ) | ( y & z ) ) // Rounds 40-59 */
103#define f3(x,y,z) ( ( x & y ) | ( z & ( x | y ) ) ) /* Rounds 40-59 */
104#define f4(x,y,z) ( x ^ y ^ z ) /* Rounds 60-79 */
105
106/* The SHA Mysterious Constants */
107
108#define K1 0x5A827999L /* Rounds 0-19 */
109#define K2 0x6ED9EBA1L /* Rounds 20-39 */
110#define K3 0x8F1BBCDCL /* Rounds 40-59 */
111#define K4 0xCA62C1D6L /* Rounds 60-79 */
112
113/* SHA initial values */
114
115#define h0init 0x67452301L
116#define h1init 0xEFCDAB89L
117#define h2init 0x98BADCFEL
118#define h3init 0x10325476L
119#define h4init 0xC3D2E1F0L
120
121/* Note that it may be necessary to add parentheses to these macros if they
122 are to be called with expressions as arguments */
123/* 32-bit rotate left - kludged with shifts */
124
125#define ROTL(n,X) ( ( ( X ) << n ) | ( ( X ) >> ( 32 - n ) ) )
126
127/* The initial expanding function. The hash function is defined over an
128 80-word expanded input array W, where the first 16 are copies of the input
129 data, and the remaining 64 are defined by
130
131 W[ i ] = W[ i - 16 ] ^ W[ i - 14 ] ^ W[ i - 8 ] ^ W[ i - 3 ]
132
133 This implementation generates these values on the fly in a circular
134 buffer - thanks to Colin Plumb, colin@nyx10.cs.du.edu for this
135 optimization.
136
137 The updated SHA changes the expanding function by adding a rotate of 1
138 bit. Thanks to Jim Gillogly, jim@rand.org, and an anonymous contributor
139 for this information */
140
141#define expand(W,i) ( W[ i & 15 ] = ROTL( 1, ( W[ i & 15 ] ^ W[ (i - 14) & 15 ] ^ \
142 W[ (i - 8) & 15 ] ^ W[ (i - 3) & 15 ] ) ) )
143
144
145/* The prototype SHA sub-round. The fundamental sub-round is:
146
147 a' = e + ROTL( 5, a ) + f( b, c, d ) + k + data;
148 b' = a;
149 c' = ROTL( 30, b );
150 d' = c;
151 e' = d;
152
153 but this is implemented by unrolling the loop 5 times and renaming the
154 variables ( e, a, b, c, d ) = ( a', b', c', d', e' ) each iteration.
155 This code is then replicated 20 times for each of the 4 functions, using
156 the next 20 values from the W[] array each time */
157
158#define subRound(a, b, c, d, e, f, k, data) \
159 ( e += ROTL( 5, a ) + f( b, c, d ) + k + data, b = ROTL( 30, b ) )
160
161#endif /* !DOXYGEN_SHOULD_SKIP_THIS */
162
163/* Perform the SHA transformation. Note that this code, like MD5, seems to
164 break some optimizing compilers due to the complexity of the expressions
165 and the size of the basic block. It may be necessary to split it into
166 sections, e.g. based on the four subrounds
167
168 Note that this corrupts the context->data area */
169
170static void
171SHATransform(dbus_uint32_t *digest, dbus_uint32_t *data)
172{
173 dbus_uint32_t A, B, C, D, E; /* Local vars */
174 dbus_uint32_t eData[16]; /* Expanded data */
175
176 /* Set up first buffer and local data buffer */
177 A = digest[0];
178 B = digest[1];
179 C = digest[2];
180 D = digest[3];
181 E = digest[4];
182 memmove (eData, data, SHA_DATASIZE);
183
184 /* Heavy mangling, in 4 sub-rounds of 20 interations each. */
185 subRound (A, B, C, D, E, f1, K1, eData[0]);
186 subRound (E, A, B, C, D, f1, K1, eData[1]);
187 subRound (D, E, A, B, C, f1, K1, eData[2]);
188 subRound (C, D, E, A, B, f1, K1, eData[3]);
189 subRound (B, C, D, E, A, f1, K1, eData[4]);
190 subRound (A, B, C, D, E, f1, K1, eData[5]);
191 subRound (E, A, B, C, D, f1, K1, eData[6]);
192 subRound (D, E, A, B, C, f1, K1, eData[7]);
193 subRound (C, D, E, A, B, f1, K1, eData[8]);
194 subRound (B, C, D, E, A, f1, K1, eData[9]);
195 subRound (A, B, C, D, E, f1, K1, eData[10]);
196 subRound (E, A, B, C, D, f1, K1, eData[11]);
197 subRound (D, E, A, B, C, f1, K1, eData[12]);
198 subRound (C, D, E, A, B, f1, K1, eData[13]);
199 subRound (B, C, D, E, A, f1, K1, eData[14]);
200 subRound (A, B, C, D, E, f1, K1, eData[15]);
201 subRound (E, A, B, C, D, f1, K1, expand ( eData, 16) );
202 subRound (D, E, A, B, C, f1, K1, expand ( eData, 17) );
203 subRound (C, D, E, A, B, f1, K1, expand ( eData, 18) );
204 subRound (B, C, D, E, A, f1, K1, expand ( eData, 19) );
205
206 subRound (A, B, C, D, E, f2, K2, expand ( eData, 20) );
207 subRound (E, A, B, C, D, f2, K2, expand ( eData, 21) );
208 subRound (D, E, A, B, C, f2, K2, expand ( eData, 22) );
209 subRound (C, D, E, A, B, f2, K2, expand ( eData, 23) );
210 subRound (B, C, D, E, A, f2, K2, expand ( eData, 24) );
211 subRound (A, B, C, D, E, f2, K2, expand ( eData, 25) );
212 subRound (E, A, B, C, D, f2, K2, expand ( eData, 26) );
213 subRound (D, E, A, B, C, f2, K2, expand ( eData, 27) );
214 subRound (C, D, E, A, B, f2, K2, expand ( eData, 28) );
215 subRound (B, C, D, E, A, f2, K2, expand ( eData, 29) );
216 subRound (A, B, C, D, E, f2, K2, expand ( eData, 30) );
217 subRound (E, A, B, C, D, f2, K2, expand ( eData, 31) );
218 subRound (D, E, A, B, C, f2, K2, expand ( eData, 32) );
219 subRound (C, D, E, A, B, f2, K2, expand ( eData, 33) );
220 subRound (B, C, D, E, A, f2, K2, expand ( eData, 34) );
221 subRound (A, B, C, D, E, f2, K2, expand ( eData, 35) );
222 subRound (E, A, B, C, D, f2, K2, expand ( eData, 36) );
223 subRound (D, E, A, B, C, f2, K2, expand ( eData, 37) );
224 subRound (C, D, E, A, B, f2, K2, expand ( eData, 38) );
225 subRound (B, C, D, E, A, f2, K2, expand ( eData, 39) );
226
227 subRound (A, B, C, D, E, f3, K3, expand ( eData, 40) );
228 subRound (E, A, B, C, D, f3, K3, expand ( eData, 41) );
229 subRound (D, E, A, B, C, f3, K3, expand ( eData, 42) );
230 subRound (C, D, E, A, B, f3, K3, expand ( eData, 43) );
231 subRound (B, C, D, E, A, f3, K3, expand ( eData, 44) );
232 subRound (A, B, C, D, E, f3, K3, expand ( eData, 45) );
233 subRound (E, A, B, C, D, f3, K3, expand ( eData, 46) );
234 subRound (D, E, A, B, C, f3, K3, expand ( eData, 47) );
235 subRound (C, D, E, A, B, f3, K3, expand ( eData, 48) );
236 subRound (B, C, D, E, A, f3, K3, expand ( eData, 49) );
237 subRound (A, B, C, D, E, f3, K3, expand ( eData, 50) );
238 subRound (E, A, B, C, D, f3, K3, expand ( eData, 51) );
239 subRound (D, E, A, B, C, f3, K3, expand ( eData, 52) );
240 subRound (C, D, E, A, B, f3, K3, expand ( eData, 53) );
241 subRound (B, C, D, E, A, f3, K3, expand ( eData, 54) );
242 subRound (A, B, C, D, E, f3, K3, expand ( eData, 55) );
243 subRound (E, A, B, C, D, f3, K3, expand ( eData, 56) );
244 subRound (D, E, A, B, C, f3, K3, expand ( eData, 57) );
245 subRound (C, D, E, A, B, f3, K3, expand ( eData, 58) );
246 subRound (B, C, D, E, A, f3, K3, expand ( eData, 59) );
247
248 subRound (A, B, C, D, E, f4, K4, expand ( eData, 60) );
249 subRound (E, A, B, C, D, f4, K4, expand ( eData, 61) );
250 subRound (D, E, A, B, C, f4, K4, expand ( eData, 62) );
251 subRound (C, D, E, A, B, f4, K4, expand ( eData, 63) );
252 subRound (B, C, D, E, A, f4, K4, expand ( eData, 64) );
253 subRound (A, B, C, D, E, f4, K4, expand ( eData, 65) );
254 subRound (E, A, B, C, D, f4, K4, expand ( eData, 66) );
255 subRound (D, E, A, B, C, f4, K4, expand ( eData, 67) );
256 subRound (C, D, E, A, B, f4, K4, expand ( eData, 68) );
257 subRound (B, C, D, E, A, f4, K4, expand ( eData, 69) );
258 subRound (A, B, C, D, E, f4, K4, expand ( eData, 70) );
259 subRound (E, A, B, C, D, f4, K4, expand ( eData, 71) );
260 subRound (D, E, A, B, C, f4, K4, expand ( eData, 72) );
261 subRound (C, D, E, A, B, f4, K4, expand ( eData, 73) );
262 subRound (B, C, D, E, A, f4, K4, expand ( eData, 74) );
263 subRound (A, B, C, D, E, f4, K4, expand ( eData, 75) );
264 subRound (E, A, B, C, D, f4, K4, expand ( eData, 76) );
265 subRound (D, E, A, B, C, f4, K4, expand ( eData, 77) );
266 subRound (C, D, E, A, B, f4, K4, expand ( eData, 78) );
267 subRound (B, C, D, E, A, f4, K4, expand ( eData, 79) );
268
269 /* Build message digest */
270 digest[0] += A;
271 digest[1] += B;
272 digest[2] += C;
273 digest[3] += D;
274 digest[4] += E;
275}
276
277/* When run on a little-endian CPU we need to perform byte reversal on an
278 array of longwords. */
279
280#ifdef WORDS_BIGENDIAN
281#define swap_words(buffer, byte_count)
282#else
283static void
284swap_words (dbus_uint32_t *buffer,
285 int byte_count)
286{
287 byte_count /= sizeof (dbus_uint32_t);
288 while (byte_count--)
289 {
290 *buffer = DBUS_UINT32_SWAP_LE_BE (*buffer);
291 ++buffer;
292 }
293}
294#endif
295
296static void
297sha_init (DBusSHAContext *context)
298{
299 /* Set the h-vars to their initial values */
300 context->digest[0] = h0init;
301 context->digest[1] = h1init;
302 context->digest[2] = h2init;
303 context->digest[3] = h3init;
304 context->digest[4] = h4init;
305
306 /* Initialise bit count */
307 context->count_lo = context->count_hi = 0;
308}
309
310static void
311sha_append (DBusSHAContext *context,
312 const unsigned char *buffer,
313 unsigned int count)
314{
315 dbus_uint32_t tmp;
316 unsigned int dataCount;
317
318 /* Update bitcount */
319 tmp = context->count_lo;
320 if (( context->count_lo = tmp + ( ( dbus_uint32_t) count << 3) ) < tmp)
321 context->count_hi++; /* Carry from low to high */
322 context->count_hi += count >> 29;
323
324 /* Get count of bytes already in data */
325 dataCount = (int) (tmp >> 3) & 0x3F;
326
327 /* Handle any leading odd-sized chunks */
328 if (dataCount)
329 {
330 unsigned char *p = (unsigned char *) context->data + dataCount;
331
332 dataCount = SHA_DATASIZE - dataCount;
333 if (count < dataCount)
334 {
335 memmove (p, buffer, count);
336 return;
337 }
338 memmove (p, buffer, dataCount);
339 swap_words (context->data, SHA_DATASIZE);
340 SHATransform (context->digest, context->data);
341 buffer += dataCount;
342 count -= dataCount;
343 }
344
345 /* Process data in SHA_DATASIZE chunks */
346 while (count >= SHA_DATASIZE)
347 {
348 memmove (context->data, buffer, SHA_DATASIZE);
349 swap_words (context->data, SHA_DATASIZE);
350 SHATransform (context->digest, context->data);
351 buffer += SHA_DATASIZE;
352 count -= SHA_DATASIZE;
353 }
354
355 /* Handle any remaining bytes of data. */
356 memmove (context->data, buffer, count);
357}
358
359
360/* Final wrapup - pad to SHA_DATASIZE-byte boundary with the bit pattern
361 1 0* (64-bit count of bits processed, MSB-first) */
362
363static void
364sha_finish (DBusSHAContext *context, unsigned char digest[20])
365{
366 int count;
367 unsigned char *data_p;
368
369 /* Compute number of bytes mod 64 */
370 count = (int) context->count_lo;
371 count = (count >> 3) & 0x3F;
372
373 /* Set the first char of padding to 0x80. This is safe since there is
374 always at least one byte free */
375 data_p = (unsigned char *) context->data + count;
376 *data_p++ = 0x80;
377
378 /* Bytes of padding needed to make 64 bytes */
379 count = SHA_DATASIZE - 1 - count;
380
381 /* Pad out to 56 mod 64 */
382 if (count < 8)
383 {
384 /* Two lots of padding: Pad the first block to 64 bytes */
385 memset (data_p, 0, count);
386 swap_words (context->data, SHA_DATASIZE);
387 SHATransform (context->digest, context->data);
388
389 /* Now fill the next block with 56 bytes */
390 memset (context->data, 0, SHA_DATASIZE - 8);
391 }
392 else
393 /* Pad block to 56 bytes */
394 memset (data_p, 0, count - 8);
395
396 /* Append length in bits and transform */
397 context->data[14] = context->count_hi;
398 context->data[15] = context->count_lo;
399
400 swap_words (context->data, SHA_DATASIZE - 8);
401 SHATransform (context->digest, context->data);
402 swap_words (context->digest, SHA_DIGESTSIZE);
403 memmove (digest, context->digest, SHA_DIGESTSIZE);
404}
405
/* End of internals */
407
419void
420_dbus_sha_init (DBusSHAContext *context)
421{
422 sha_init (context);
423}
424
431void
432_dbus_sha_update (DBusSHAContext *context,
433 const DBusString *data)
434{
435 unsigned int inputLen;
436 const unsigned char *input;
437
438 input = (const unsigned char*) _dbus_string_get_const_data (data);
439 inputLen = _dbus_string_get_length (data);
440
441 sha_append (context, input, inputLen);
442}
443
455dbus_bool_t
456_dbus_sha_final (DBusSHAContext *context,
457 DBusString *results)
458{
459 unsigned char digest[20];
460
461 sha_finish (context, digest);
462
463 if (!_dbus_string_append_len (results, (const char *) digest, 20))
464 return FALSE;
465
466 /* some kind of security paranoia, though it seems pointless
467 * to me given the nonzeroed stuff flying around
468 */
469 _DBUS_ZERO(*context);
470
471 return TRUE;
472}
473
482dbus_bool_t
483_dbus_sha_compute (const DBusString *data,
484 DBusString *ascii_output)
485{
486 DBusSHAContext context;
487 DBusString digest;
488
489 _dbus_sha_init (&context);
490
491 _dbus_sha_update (&context, data);
492
493 if (!_dbus_string_init (&digest))
494 return FALSE;
495
496 if (!_dbus_sha_final (&context, &digest))
497 goto error;
498
499 if (!_dbus_string_hex_encode (&digest, 0, ascii_output,
500 _dbus_string_get_length (ascii_output)))
501 goto error;
502
503 _dbus_string_free (&digest);
504
505 return TRUE;
506
507 error:
508 _dbus_string_free (&digest);
509 return FALSE;
510}
511
/* end of exported functions */
_DBUS_ZERO
#define _DBUS_ZERO(object)
Sets all bits in an object to zero.
Definition dbus-internals.h:194
TRUE
#define TRUE
Expands to "1".
Definition dbus-macros.h:39
FALSE
#define FALSE
Expands to "0".
Definition dbus-macros.h:42
_dbus_sha_compute
dbus_bool_t _dbus_sha_compute(const DBusString *data, DBusString *ascii_output)
Computes the ASCII hex-encoded shasum of the given data and appends it to the output string.
Definition dbus-sha.c:483
_dbus_sha_init
void _dbus_sha_init(DBusSHAContext *context)
Initializes the SHA context.
Definition dbus-sha.c:420
_dbus_sha_update
void _dbus_sha_update(DBusSHAContext *context, const DBusString *data)
Feeds more data into an existing shasum computation.
Definition dbus-sha.c:432
_dbus_sha_final
dbus_bool_t _dbus_sha_final(DBusSHAContext *context, DBusString *results)
SHA finalization.
Definition dbus-sha.c:456
_dbus_string_init
dbus_bool_t _dbus_string_init(DBusString *str)
Initializes a string.
Definition dbus-string.c:182
_dbus_string_append_len
dbus_bool_t _dbus_string_append_len(DBusString *str, const char *buffer, int len)
Appends block of bytes with the given length to a DBusString.
Definition dbus-string.c:1168
_dbus_string_free
void _dbus_string_free(DBusString *str)
Frees a string created by _dbus_string_init(), and fills it with the same contents as _DBUS_STRING_IN...
Definition dbus-string.c:278
_dbus_string_hex_encode
dbus_bool_t _dbus_string_hex_encode(const DBusString *source, int start, DBusString *dest, int insert_at)
Encodes a string in hex, the way MD5 and SHA-1 are usually encoded.
Definition dbus-string.c:2345
DBusSHAContext
Struct storing state of the SHA algorithm.
Definition dbus-sha.h:38
DBusSHAContext::digest
dbus_uint32_t digest[5]
Message digest.
Definition dbus-sha.h:39
DBusSHAContext::data
dbus_uint32_t data[16]
SHA data buffer.
Definition dbus-sha.h:42
DBusSHAContext::count_lo
dbus_uint32_t count_lo
64-bit bit count
Definition dbus-sha.h:40
DBusSHAContext::count_hi
dbus_uint32_t count_hi
No clue.
Definition dbus-sha.h:41
DBusString
Definition dbus-string.h:43