1/*
2 * sha1.c
3 *
4 * Description:
5 * This file implements the Secure Hashing Algorithm 1 as
6 * defined in FIPS PUB 180-1 published April 17, 1995.
7 *
8 * The SHA-1, produces a 160-bit message digest for a given
9 * data stream. It should take about 2**n steps to find a
10 * message with the same digest as a given message and
11 * 2**(n/2) to find any two messages with the same digest,
12 * when n is the digest size in bits. Therefore, this
13 * algorithm can serve as a means of providing a
14 * "fingerprint" for a message.
15 *
16 * Portability Issues:
17 * SHA-1 is defined in terms of 32-bit "words". This code
18 * uses <stdint.h> (included via "sha1.h" to define 32 and 8
19 * bit unsigned integer types. If your C compiler does not
20 * support 32 bit unsigned integers, this code is not
21 * appropriate.
22 *
23 * Caveats:
24 * SHA-1 is designed to work with messages less than 2^64 bits
25 * long. Although SHA-1 allows a message digest to be generated
26 * for messages of any number of bits less than 2^64, this
27 * implementation only works with messages with a length that is
28 * a multiple of the size of an 8-bit character.
29 *
30 */
31
32#ifdef HAVE_CONFIG_H
33#include "config.h"
34#endif
35#include "base/ints.h"
36#include "base/sha1_rfc3174.h"
37
38/*
39 * Define the SHA1 circular left shift macro
40 */
41#define SHA1CircularShift(bits,word) \
42 (((word) << (bits)) | ((word) >> (32-(bits))))
43
44/* Local Function Prototyptes */
45void SHA1PadMessage(SHA1Context *);
46void SHA1ProcessMessageBlock(SHA1Context *);
47
48/*
49 * SHA1Reset
50 *
51 * Description:
52 * This function will initialize the SHA1Context in preparation
53 * for computing a new SHA1 message digest.
54 *
55 * Parameters:
56 * context: [in/out]
57 * The context to reset.
58 *
59 * Returns:
60 * sha Error Code.
61 *
62 */
63int SHA1Reset(SHA1Context *context)
64{
65 if (!context)
66 {
67 return shaNull;
68 }
69
70 context->Length_Low = 0;
71 context->Length_High = 0;
72 context->Message_Block_Index = 0;
73
74 context->Intermediate_Hash[0] = 0x67452301;
75 context->Intermediate_Hash[1] = 0xEFCDAB89;
76 context->Intermediate_Hash[2] = 0x98BADCFE;
77 context->Intermediate_Hash[3] = 0x10325476;
78 context->Intermediate_Hash[4] = 0xC3D2E1F0;
79
80 context->Computed = 0;
81 context->Corrupted = 0;
82
83 return shaSuccess;
84}
85
86/*
87 * SHA1Result
88 *
89 * Description:
90 * This function will return the 160-bit message digest into the
91 * Message_Digest array provided by the caller.
92 * NOTE: The first octet of hash is stored in the 0th element,
93 * the last octet of hash in the 19th element.
94 *
95 * Parameters:
96 * context: [in/out]
97 * The context to use to calculate the SHA-1 hash.
98 * Message_Digest: [out]
99 * Where the digest is returned.
100 *
101 * Returns:
102 * sha Error Code.
103 *
104 */
105int SHA1Result( SHA1Context *context,
106 uint8_t Message_Digest[SHA1HashSize])
107{
108 int i;
109
110 if (!context || !Message_Digest)
111 {
112 return shaNull;
113 }
114
115 if (context->Corrupted)
116 {
117 return context->Corrupted;
118 }
119
120 if (!context->Computed)
121 {
122 SHA1PadMessage(context);
123 for(i=0; i<64; ++i)
124 {
125 /* message may be sensitive, clear it out */
126 context->Message_Block[i] = 0;
127 }
128 context->Length_Low = 0; /* and clear length */
129 context->Length_High = 0;
130 context->Computed = 1;
131
132 }
133
134 for(i = 0; i < SHA1HashSize; ++i)
135 {
136 Message_Digest[i] = context->Intermediate_Hash[i>>2]
137 >> 8 * ( 3 - ( i & 0x03 ) );
138 }
139
140 return shaSuccess;
141}
142
143/*
144 * SHA1Input
145 *
146 * Description:
147 * This function accepts an array of octets as the next portion
148 * of the message.
149 *
150 * Parameters:
151 * context: [in/out]
152 * The SHA context to update
153 * message_array: [in]
154 * An array of characters representing the next portion of
155 * the message.
156 * length: [in]
157 * The length of the message in message_array
158 *
159 * Returns:
160 * sha Error Code.
161 *
162 */
163int SHA1Input( SHA1Context *context,
164 const uint8_t *message_array,
165 unsigned int length)
166{
167 if (!length)
168 {
169 return shaSuccess;
170 }
171
172 if (!context || !message_array)
173 {
174 return shaNull;
175 }
176
177 if (context->Computed)
178 {
179 context->Corrupted = shaStateError;
180
181 return shaStateError;
182 }
183
184 if (context->Corrupted)
185 {
186 return context->Corrupted;
187 }
188 while(length-- && !context->Corrupted)
189 {
190 context->Message_Block[context->Message_Block_Index++] =
191 (*message_array & 0xFF);
192
193 context->Length_Low += 8;
194 if (context->Length_Low == 0)
195 {
196 context->Length_High++;
197 if (context->Length_High == 0)
198 {
199 /* Message is too long */
200 context->Corrupted = 1;
201 }
202 }
203
204 if (context->Message_Block_Index == 64)
205 {
206 SHA1ProcessMessageBlock(context);
207 }
208
209 message_array++;
210 }
211
212 return shaSuccess;
213}
214
215/*
216 * SHA1ProcessMessageBlock
217 *
218 * Description:
219 * This function will process the next 512 bits of the message
220 * stored in the Message_Block array.
221 *
222 * Parameters:
223 * None.
224 *
225 * Returns:
226 * Nothing.
227 *
228 * Comments:
229
230 * Many of the variable names in this code, especially the
231 * single character names, were used because those were the
232 * names used in the publication.
233 *
234 *
235 */
236void SHA1ProcessMessageBlock(SHA1Context *context)
237{
238 const uint32_t K[] = { /* Constants defined in SHA-1 */
239 0x5A827999,
240 0x6ED9EBA1,
241 0x8F1BBCDC,
242 0xCA62C1D6
243 };
244 int t; /* Loop counter */
245 uint32_t temp; /* Temporary word value */
246 uint32_t W[80]; /* Word sequence */
247 uint32_t A, B, C, D, E; /* Word buffers */
248
249 /*
250 * Initialize the first 16 words in the array W
251 */
252 for(t = 0; t < 16; t++)
253 {
254 W[t] = context->Message_Block[t * 4] << 24;
255 W[t] |= context->Message_Block[t * 4 + 1] << 16;
256 W[t] |= context->Message_Block[t * 4 + 2] << 8;
257 W[t] |= context->Message_Block[t * 4 + 3];
258 }
259
260 for(t = 16; t < 80; t++)
261 {
262 W[t] = SHA1CircularShift(1,W[t-3] ^ W[t-8] ^ W[t-14] ^ W[t-16]);
263 }
264
265 A = context->Intermediate_Hash[0];
266 B = context->Intermediate_Hash[1];
267 C = context->Intermediate_Hash[2];
268 D = context->Intermediate_Hash[3];
269 E = context->Intermediate_Hash[4];
270
271 for(t = 0; t < 20; t++)
272 {
273 temp = SHA1CircularShift(5,A) +
274 ((B & C) | ((~B) & D)) + E + W[t] + K[0];
275 E = D;
276 D = C;
277 C = SHA1CircularShift(30,B);
278
279 B = A;
280 A = temp;
281 }
282
283 for(t = 20; t < 40; t++)
284 {
285 temp = SHA1CircularShift(5,A) + (B ^ C ^ D) + E + W[t] + K[1];
286 E = D;
287 D = C;
288 C = SHA1CircularShift(30,B);
289 B = A;
290 A = temp;
291 }
292
293 for(t = 40; t < 60; t++)
294 {
295 temp = SHA1CircularShift(5,A) +
296 ((B & C) | (B & D) | (C & D)) + E + W[t] + K[2];
297 E = D;
298 D = C;
299 C = SHA1CircularShift(30,B);
300 B = A;
301 A = temp;
302 }
303
304 for(t = 60; t < 80; t++)
305 {
306 temp = SHA1CircularShift(5,A) + (B ^ C ^ D) + E + W[t] + K[3];
307 E = D;
308 D = C;
309 C = SHA1CircularShift(30,B);
310 B = A;
311 A = temp;
312 }
313
314 context->Intermediate_Hash[0] += A;
315 context->Intermediate_Hash[1] += B;
316 context->Intermediate_Hash[2] += C;
317 context->Intermediate_Hash[3] += D;
318 context->Intermediate_Hash[4] += E;
319
320 context->Message_Block_Index = 0;
321}
322
323/*
324 * SHA1PadMessage
325 *
326
327 * Description:
328 * According to the standard, the message must be padded to an even
329 * 512 bits. The first padding bit must be a '1'. The last 64
330 * bits represent the length of the original message. All bits in
331 * between should be 0. This function will pad the message
332 * according to those rules by filling the Message_Block array
333 * accordingly. It will also call the ProcessMessageBlock function
334 * provided appropriately. When it returns, it can be assumed that
335 * the message digest has been computed.
336 *
337 * Parameters:
338 * context: [in/out]
339 * The context to pad
340 * ProcessMessageBlock: [in]
341 * The appropriate SHA*ProcessMessageBlock function
342 * Returns:
343 * Nothing.
344 *
345 */
346
347void SHA1PadMessage(SHA1Context *context)
348{
349 /*
350 * Check to see if the current message block is too small to hold
351 * the initial padding bits and length. If so, we will pad the
352 * block, process it, and then continue padding into a second
353 * block.
354 */
355 if (context->Message_Block_Index > 55)
356 {
357 context->Message_Block[context->Message_Block_Index++] = 0x80;
358 while(context->Message_Block_Index < 64)
359 {
360 context->Message_Block[context->Message_Block_Index++] = 0;
361 }
362
363 SHA1ProcessMessageBlock(context);
364
365 while(context->Message_Block_Index < 56)
366 {
367 context->Message_Block[context->Message_Block_Index++] = 0;
368 }
369 }
370 else
371 {
372 context->Message_Block[context->Message_Block_Index++] = 0x80;
373 while(context->Message_Block_Index < 56)
374 {
375
376 context->Message_Block[context->Message_Block_Index++] = 0;
377 }
378 }
379
380 /*
381 * Store the message length as the last 8 octets
382 */
383 context->Message_Block[56] = context->Length_High >> 24;
384 context->Message_Block[57] = context->Length_High >> 16;
385 context->Message_Block[58] = context->Length_High >> 8;
386 context->Message_Block[59] = context->Length_High;
387 context->Message_Block[60] = context->Length_Low >> 24;
388 context->Message_Block[61] = context->Length_Low >> 16;
389 context->Message_Block[62] = context->Length_Low >> 8;
390 context->Message_Block[63] = context->Length_Low;
391
392 SHA1ProcessMessageBlock(context);
393}
394