Line data Source code
1 : /**************************** sha1.c ***************************/
2 : /***************** See RFC 6234 for details. *******************/
3 : /* Copyright (c) 2011 IETF Trust and the persons identified as */
4 : /* authors of the code. All rights reserved. */
5 : /* See sha.h for terms of use and redistribution. */
6 :
7 : /*
8 : * Description:
9 : * This file implements the Secure Hash Algorithm SHA-1
10 : * as defined in the U.S. National Institute of Standards
11 : * and Technology Federal Information Processing Standards
12 : * Publication (FIPS PUB) 180-3 published in October 2008
13 : * and formerly defined in its predecessors, FIPS PUB 180-1
14 : * and FIP PUB 180-2.
15 : *
16 : * A combined document showing all algorithms is available at
17 : * http://csrc.nist.gov/publications/fips/
18 : * fips180-3/fips180-3_final.pdf
19 : *
20 : * The SHA-1 algorithm produces a 160-bit message digest for a
21 : * given data stream that can serve as a means of providing a
22 : * "fingerprint" for a message.
23 : *
24 : * Portability Issues:
25 : * SHA-1 is defined in terms of 32-bit "words". This code
26 : * uses <stdint.h> (included via "sha.h") to define 32- and
27 : * 8-bit unsigned integer types. If your C compiler does
28 : * not support 32-bit unsigned integers, this code is not
29 : * appropriate.
30 : *
31 : * Caveats:
32 : * SHA-1 is designed to work with messages less than 2^64 bits
33 : * long. This implementation uses SHA1Input() to hash the bits
34 : * that are a multiple of the size of an 8-bit octet, and then
35 : * optionally uses SHA1FinalBits() to hash the final few bits of
36 : * the input.
37 : */
38 :
39 : #include "sha.h"
40 : #include "sha-private.h"
41 :
42 : /*
43 : * Define the SHA1 circular left shift macro
44 : */
45 : #define SHA1_ROTL(bits,word) \
46 : (((word) << (bits)) | ((word) >> (32-(bits))))
47 :
48 : /*
49 : * Add "length" to the length.
50 : * Set Corrupted when overflow has occurred.
51 : */
52 : #define SHA1AddLength(context, length) \
53 : (addTemp = (context)->Length_Low, \
54 : (context)->Corrupted = \
55 : (((context)->Length_Low += (length)) < addTemp) && \
56 : (++(context)->Length_High == 0) ? shaInputTooLong \
57 : : (context)->Corrupted )
58 :
59 : /* Local Function Prototypes */
60 : static void SHA1ProcessMessageBlock(SHA1Context *context);
61 : static void SHA1Finalize(SHA1Context *context, uint8_t Pad_Byte);
62 : static void SHA1PadMessage(SHA1Context *context, uint8_t Pad_Byte);
63 :
64 : /*
65 : * SHA1Reset
66 : *
67 : * Description:
68 : * This function will initialize the SHA1Context in preparation
69 : * for computing a new SHA1 message digest.
70 : *
71 : * Parameters:
72 : * context: [in/out]
73 : * The context to reset.
74 : *
75 : * Returns:
76 : * sha Error Code.
77 : *
78 : */
79 2 : int SHA1Reset(SHA1Context *context)
80 : {
81 2 : if (!context) return shaNull;
82 :
83 2 : context->Length_High = context->Length_Low = 0;
84 2 : context->Message_Block_Index = 0;
85 :
86 : /* Initial Hash Values: FIPS 180-3 section 5.3.1 */
87 2 : context->Intermediate_Hash[0] = 0x67452301;
88 2 : context->Intermediate_Hash[1] = 0xEFCDAB89;
89 2 : context->Intermediate_Hash[2] = 0x98BADCFE;
90 2 : context->Intermediate_Hash[3] = 0x10325476;
91 2 : context->Intermediate_Hash[4] = 0xC3D2E1F0;
92 :
93 2 : context->Computed = 0;
94 2 : context->Corrupted = shaSuccess;
95 :
96 2 : return shaSuccess;
97 : }
98 :
99 : /*
100 : * SHA1Input
101 : *
102 : * Description:
103 : * This function accepts an array of octets as the next portion
104 : * of the message.
105 : *
106 : * Parameters:
107 : * context: [in/out]
108 : * The SHA context to update.
109 : * message_array[ ]: [in]
110 : * An array of octets representing the next portion of
111 : * the message.
112 : * length: [in]
113 : * The length of the message in message_array.
114 : *
115 : * Returns:
116 : * sha Error Code.
117 : *
118 : */
119 3 : int SHA1Input(SHA1Context *context,
120 : const uint8_t *message_array, unsigned length)
121 : {
122 3 : if (!context) return shaNull;
123 3 : if (!length) return shaSuccess;
124 3 : if (!message_array) return shaNull;
125 3 : if (context->Computed) return context->Corrupted = shaStateError;
126 3 : if (context->Corrupted) return context->Corrupted;
127 :
128 146 : while (length--) {
129 143 : context->Message_Block[context->Message_Block_Index++] =
130 143 : *message_array;
131 :
132 143 : uint32_t addTemp;
133 143 : if ((SHA1AddLength(context, 8) == shaSuccess) &&
134 : (context->Message_Block_Index == SHA1_Message_Block_Size))
135 2 : SHA1ProcessMessageBlock(context);
136 :
137 143 : message_array++;
138 : }
139 :
140 3 : return context->Corrupted;
141 : }
142 :
143 : /*
144 : * SHA1FinalBits
145 : *
146 : * Description:
147 : * This function will add in any final bits of the message.
148 : *
149 : * Parameters:
150 : * context: [in/out]
151 : * The SHA context to update.
152 : * message_bits: [in]
153 : * The final bits of the message, in the upper portion of the
154 : * byte. (Use 0b###00000 instead of 0b00000### to input the
155 : * three bits ###.)
156 : * length: [in]
157 : * The number of bits in message_bits, between 1 and 7.
158 : *
159 : * Returns:
160 : * sha Error Code.
161 : */
162 0 : int SHA1FinalBits(SHA1Context *context, uint8_t message_bits,
163 : unsigned int length)
164 : {
165 0 : static uint8_t masks[8] = {
166 : /* 0 0b00000000 */ 0x00, /* 1 0b10000000 */ 0x80,
167 : /* 2 0b11000000 */ 0xC0, /* 3 0b11100000 */ 0xE0,
168 : /* 4 0b11110000 */ 0xF0, /* 5 0b11111000 */ 0xF8,
169 : /* 6 0b11111100 */ 0xFC, /* 7 0b11111110 */ 0xFE
170 : };
171 :
172 0 : static uint8_t markbit[8] = {
173 : /* 0 0b10000000 */ 0x80, /* 1 0b01000000 */ 0x40,
174 : /* 2 0b00100000 */ 0x20, /* 3 0b00010000 */ 0x10,
175 : /* 4 0b00001000 */ 0x08, /* 5 0b00000100 */ 0x04,
176 : /* 6 0b00000010 */ 0x02, /* 7 0b00000001 */ 0x01
177 : };
178 :
179 0 : if (!context) return shaNull;
180 0 : if (!length) return shaSuccess;
181 0 : if (context->Corrupted) return context->Corrupted;
182 0 : if (context->Computed) return context->Corrupted = shaStateError;
183 0 : if (length >= 8) return context->Corrupted = shaBadParam;
184 :
185 0 : uint32_t addTemp;
186 0 : SHA1AddLength(context, length);
187 0 : SHA1Finalize(context,
188 0 : (uint8_t) ((message_bits & masks[length]) | markbit[length]));
189 :
190 0 : return context->Corrupted;
191 : }
192 :
193 : /*
194 : * SHA1Result
195 : *
196 : * Description:
197 : * This function will return the 160-bit message digest
198 : * into the Message_Digest array provided by the caller.
199 : * NOTE:
200 : * The first octet of hash is stored in the element with index 0,
201 : * the last octet of hash in the element with index 19.
202 : *
203 : * Parameters:
204 : * context: [in/out]
205 : * The context to use to calculate the SHA-1 hash.
206 : * Message_Digest[ ]: [out]
207 : * Where the digest is returned.
208 : *
209 : * Returns:
210 : * sha Error Code.
211 : *
212 : */
213 2 : int SHA1Result(SHA1Context *context,
214 : uint8_t Message_Digest[SHA1HashSize])
215 : {
216 2 : int i;
217 :
218 2 : if (!context) return shaNull;
219 2 : if (!Message_Digest) return shaNull;
220 2 : if (context->Corrupted) return context->Corrupted;
221 :
222 2 : if (!context->Computed)
223 2 : SHA1Finalize(context, 0x80);
224 :
225 42 : for (i = 0; i < SHA1HashSize; ++i)
226 40 : Message_Digest[i] = (uint8_t) (context->Intermediate_Hash[i>>2]
227 40 : >> (8 * ( 3 - ( i & 0x03 ) )));
228 :
229 : return shaSuccess;
230 : }
231 :
232 : /*
233 : * SHA1ProcessMessageBlock
234 : *
235 : * Description:
236 : * This helper function will process the next 512 bits of the
237 : * message stored in the Message_Block array.
238 : *
239 : * Parameters:
240 : * context: [in/out]
241 : * The SHA context to update.
242 : *
243 : * Returns:
244 : * Nothing.
245 : *
246 : * Comments:
247 : * Many of the variable names in this code, especially the
248 : * single character names, were used because those were the
249 : * names used in the Secure Hash Standard.
250 : */
251 4 : static void SHA1ProcessMessageBlock(SHA1Context *context)
252 : {
253 : /* Constants defined in FIPS 180-3, section 4.2.1 */
254 4 : const uint32_t K[4] = {
255 : 0x5A827999, 0x6ED9EBA1, 0x8F1BBCDC, 0xCA62C1D6
256 : };
257 4 : int t; /* Loop counter */
258 4 : uint32_t temp; /* Temporary word value */
259 4 : uint32_t W[80]; /* Word sequence */
260 4 : uint32_t A, B, C, D, E; /* Word buffers */
261 :
262 : /*
263 : * Initialize the first 16 words in the array W
264 : */
265 68 : for (t = 0; t < 16; t++) {
266 64 : W[t] = ((uint32_t)context->Message_Block[t * 4]) << 24;
267 64 : W[t] |= ((uint32_t)context->Message_Block[t * 4 + 1]) << 16;
268 64 : W[t] |= ((uint32_t)context->Message_Block[t * 4 + 2]) << 8;
269 64 : W[t] |= ((uint32_t)context->Message_Block[t * 4 + 3]);
270 : }
271 :
272 260 : for (t = 16; t < 80; t++)
273 256 : W[t] = SHA1_ROTL(1, W[t-3] ^ W[t-8] ^ W[t-14] ^ W[t-16]);
274 :
275 4 : A = context->Intermediate_Hash[0];
276 4 : B = context->Intermediate_Hash[1];
277 4 : C = context->Intermediate_Hash[2];
278 4 : D = context->Intermediate_Hash[3];
279 4 : E = context->Intermediate_Hash[4];
280 :
281 84 : for (t = 0; t < 20; t++) {
282 80 : temp = SHA1_ROTL(5,A) + SHA_Ch(B, C, D) + E + W[t] + K[0];
283 80 : E = D;
284 80 : D = C;
285 80 : C = SHA1_ROTL(30,B);
286 80 : B = A;
287 80 : A = temp;
288 : }
289 :
290 84 : for (t = 20; t < 40; t++) {
291 80 : temp = SHA1_ROTL(5,A) + SHA_Parity(B, C, D) + E + W[t] + K[1];
292 80 : E = D;
293 80 : D = C;
294 80 : C = SHA1_ROTL(30,B);
295 80 : B = A;
296 80 : A = temp;
297 : }
298 :
299 84 : for (t = 40; t < 60; t++) {
300 80 : temp = SHA1_ROTL(5,A) + SHA_Maj(B, C, D) + E + W[t] + K[2];
301 80 : E = D;
302 80 : D = C;
303 80 : C = SHA1_ROTL(30,B);
304 80 : B = A;
305 80 : A = temp;
306 : }
307 :
308 84 : for (t = 60; t < 80; t++) {
309 80 : temp = SHA1_ROTL(5,A) + SHA_Parity(B, C, D) + E + W[t] + K[3];
310 80 : E = D;
311 80 : D = C;
312 80 : C = SHA1_ROTL(30,B);
313 80 : B = A;
314 80 : A = temp;
315 : }
316 :
317 4 : context->Intermediate_Hash[0] += A;
318 4 : context->Intermediate_Hash[1] += B;
319 4 : context->Intermediate_Hash[2] += C;
320 4 : context->Intermediate_Hash[3] += D;
321 4 : context->Intermediate_Hash[4] += E;
322 4 : context->Message_Block_Index = 0;
323 4 : }
324 :
325 : /*
326 : * SHA1Finalize
327 : *
328 : * Description:
329 : * This helper function finishes off the digest calculations.
330 : *
331 : * Parameters:
332 : * context: [in/out]
333 : * The SHA context to update.
334 : * Pad_Byte: [in]
335 : * The last byte to add to the message block before the 0-padding
336 : * and length. This will contain the last bits of the message
337 : * followed by another single bit. If the message was an
338 : * exact multiple of 8-bits long, Pad_Byte will be 0x80.
339 : *
340 : * Returns:
341 : * sha Error Code.
342 : *
343 : */
344 2 : static void SHA1Finalize(SHA1Context *context, uint8_t Pad_Byte)
345 : {
346 2 : int i;
347 2 : SHA1PadMessage(context, Pad_Byte);
348 : /* message may be sensitive, clear it out */
349 132 : for (i = 0; i < SHA1_Message_Block_Size; ++i)
350 128 : context->Message_Block[i] = 0;
351 2 : context->Length_High = 0; /* and clear length */
352 2 : context->Length_Low = 0;
353 2 : context->Computed = 1;
354 2 : }
355 :
356 : /*
357 : * SHA1PadMessage
358 : *
359 : * Description:
360 : * According to the standard, the message must be padded to the next
361 : * even multiple of 512 bits. The first padding bit must be a '1'.
362 : * The last 64 bits represent the length of the original message.
363 : * All bits in between should be 0. This helper function will pad
364 : * the message according to those rules by filling the Message_Block
365 : * array accordingly. When it returns, it can be assumed that the
366 : * message digest has been computed.
367 : *
368 : * Parameters:
369 : * context: [in/out]
370 : * The context to pad.
371 : * Pad_Byte: [in]
372 : * The last byte to add to the message block before the 0-padding
373 : * and length. This will contain the last bits of the message
374 : * followed by another single bit. If the message was an
375 : * exact multiple of 8-bits long, Pad_Byte will be 0x80.
376 : *
377 : * Returns:
378 : * Nothing.
379 : */
380 2 : static void SHA1PadMessage(SHA1Context *context, uint8_t Pad_Byte)
381 : {
382 : /*
383 : * Check to see if the current message block is too small to hold
384 : * the initial padding bits and length. If so, we will pad the
385 : * block, process it, and then continue padding into a second
386 : * block.
387 : */
388 2 : if (context->Message_Block_Index >= (SHA1_Message_Block_Size - 8)) {
389 0 : context->Message_Block[context->Message_Block_Index++] = Pad_Byte;
390 0 : while (context->Message_Block_Index < SHA1_Message_Block_Size)
391 0 : context->Message_Block[context->Message_Block_Index++] = 0;
392 :
393 0 : SHA1ProcessMessageBlock(context);
394 : } else
395 2 : context->Message_Block[context->Message_Block_Index++] = Pad_Byte;
396 :
397 97 : while (context->Message_Block_Index < (SHA1_Message_Block_Size - 8))
398 95 : context->Message_Block[context->Message_Block_Index++] = 0;
399 :
400 : /*
401 : * Store the message length as the last 8 octets
402 : */
403 2 : context->Message_Block[56] = (uint8_t) (context->Length_High >> 24);
404 2 : context->Message_Block[57] = (uint8_t) (context->Length_High >> 16);
405 2 : context->Message_Block[58] = (uint8_t) (context->Length_High >> 8);
406 2 : context->Message_Block[59] = (uint8_t) (context->Length_High);
407 2 : context->Message_Block[60] = (uint8_t) (context->Length_Low >> 24);
408 2 : context->Message_Block[61] = (uint8_t) (context->Length_Low >> 16);
409 2 : context->Message_Block[62] = (uint8_t) (context->Length_Low >> 8);
410 2 : context->Message_Block[63] = (uint8_t) (context->Length_Low);
411 :
412 2 : SHA1ProcessMessageBlock(context);
413 2 : }
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