1  /*
  2   *  Copyright (C) 2021 - This file is part of libecc project
  3   *
  4   *  Authors:
  5   *      Ryad BENADJILA <ryadbenadjila@gmail.com>
  6   *      Arnaud EBALARD <arnaud.ebalard@ssi.gouv.fr>
  7   *
  8   *  This software is licensed under a dual BSD and GPL v2 license.
  9   *  See LICENSE file at the root folder of the project.
 10   */
 11  #include "md2.h"
 12  
 13  /* All the inner MD-2 operations */
 14  static const u8 PI_SUBST[256] = {
 15  	41, 46, 67, 201, 162, 216, 124, 1, 61, 54, 84, 161, 236, 240, 6,
 16  	19, 98, 167, 5, 243, 192, 199, 115, 140, 152, 147, 43, 217, 188,
 17  	76, 130, 202, 30, 155, 87, 60, 253, 212, 224, 22, 103, 66, 111, 24,
 18  	138, 23, 229, 18, 190, 78, 196, 214, 218, 158, 222, 73, 160, 251,
 19  	245, 142, 187, 47, 238, 122, 169, 104, 121, 145, 21, 178, 7, 63,
 20  	148, 194, 16, 137, 11, 34, 95, 33, 128, 127, 93, 154, 90, 144, 50,
 21  	39, 53, 62, 204, 231, 191, 247, 151, 3, 255, 25, 48, 179, 72, 165,
 22  	181, 209, 215, 94, 146, 42, 172, 86, 170, 198, 79, 184, 56, 210,
 23  	150, 164, 125, 182, 118, 252, 107, 226, 156, 116, 4, 241, 69, 157,
 24  	112, 89, 100, 113, 135, 32, 134, 91, 207, 101, 230, 45, 168, 2, 27,
 25  	96, 37, 173, 174, 176, 185, 246, 28, 70, 97, 105, 52, 64, 126, 15,
 26  	85, 71, 163, 35, 221, 81, 175, 58, 195, 92, 249, 206, 186, 197,
 27  	234, 38, 44, 83, 13, 110, 133, 40, 132, 9, 211, 223, 205, 244, 65,
 28  	129, 77, 82, 106, 220, 55, 200, 108, 193, 171, 250, 36, 225, 123,
 29  	8, 12, 189, 177, 74, 120, 136, 149, 139, 227, 99, 232, 109, 233,
 30  	203, 213, 254, 59, 0, 29, 57, 242, 239, 183, 14, 102, 88, 208, 228,
 31  	166, 119, 114, 248, 235, 117, 75, 10, 49, 68, 80, 180, 143, 237,
 32  	31, 26, 219, 153, 141, 51, 159, 17, 131, 20
 33  };
 34  
 35  /* MD-2 core processing. Returns 0 on success, -1 on error. */
 36  ATTRIBUTE_WARN_UNUSED_RET static inline int md2_process(md2_context *ctx,
 37  			   const u8 data[MD2_BLOCK_SIZE])
 38  {
 39  	int ret;
 40  	unsigned int i, j, t;
 41  	u8 x[3 * MD2_BLOCK_SIZE];
 42  
 43  	MUST_HAVE((data != NULL), ret, err);
 44  	MD2_HASH_CHECK_INITIALIZED(ctx, ret, err);
 45  
 46  	/* Form state, block, state ^ block */
 47  	ret = local_memcpy(&x[0], ctx->md2_state, MD2_BLOCK_SIZE); EG(ret, err);
 48  	ret = local_memcpy(&x[MD2_BLOCK_SIZE], data, MD2_BLOCK_SIZE); EG(ret, err);
 49  	for(i = 0; i < MD2_BLOCK_SIZE; i++){
 50  		x[(2 * MD2_BLOCK_SIZE) + i] = (ctx->md2_state[i] ^ data[i]);
 51  	}
 52  	/* Encrypt the block during 18 rounds */
 53  	t = 0;
 54  	for(i = 0; i < 18; i++){
 55  		for (j = 0; j < (3 * MD2_BLOCK_SIZE); j++){
 56  			x[j] ^= PI_SUBST[t];
 57  			t = x[j];
 58  		}
 59  		t = (t + i) & 0xff;
 60  	}
 61  	/* Save the new state */
 62  	ret = local_memcpy(ctx->md2_state, &x[0], MD2_BLOCK_SIZE); EG(ret, err);
 63  	/* Update the checksum */
 64  	t = ctx->md2_checksum[MD2_BLOCK_SIZE - 1];
 65  	for(i = 0; i < MD2_BLOCK_SIZE; i++){
 66  		ctx->md2_checksum[i] ^= PI_SUBST[data[i] ^ t];
 67  		t = ctx->md2_checksum[i];
 68  	}
 69  
 70  	/* Zeroize x as not needed anymore */
 71  	ret = local_memset(x, 0, sizeof(x)); EG(ret, err);
 72  
 73  	ret = 0;
 74  
 75  err:
 76  	return ret;
 77  }
 78  
 79  /* Init hash function. Returns 0 on success, -1 on error. */
 80  ATTRIBUTE_WARN_UNUSED_RET int md2_init(md2_context *ctx)
 81  {
 82  	int ret;
 83  
 84  	MUST_HAVE((ctx != NULL), ret, err);
 85  
 86          /* Sanity check on size */
 87  	MUST_HAVE((MD2_DIGEST_SIZE <= MAX_DIGEST_SIZE), ret, err);
 88  
 89  	ctx->md2_total = 0;
 90  	/* Zeroize the state */
 91  	ret = local_memset(ctx->md2_state, 0, sizeof(ctx->md2_state)); EG(ret, err);
 92  	/* Zeroize the checksum */
 93  	ret = local_memset(ctx->md2_checksum, 0, sizeof(ctx->md2_checksum)); EG(ret, err);
 94  
 95  	/* Tell that we are initialized */
 96  	ctx->magic = MD2_HASH_MAGIC;
 97  
 98  	ret = 0;
 99  
100  err:
101  	return ret;
102  }
103  
104  ATTRIBUTE_WARN_UNUSED_RET int md2_update(md2_context *ctx, const u8 *input, u32 ilen)
105  {
106  	const u8 *data_ptr = input;
107  	u32 remain_ilen = ilen;
108  	u16 fill;
109  	u8 left;
110  	int ret;
111  
112  	MUST_HAVE((input != NULL) || (ilen == 0), ret, err);
113  	MD2_HASH_CHECK_INITIALIZED(ctx, ret, err);
114  
115  	/* Nothing to process, return */
116  	if (ilen == 0) {
117  		ret = 0;
118  		goto err;
119  	}
120  
121  	/* Get what's left in our local buffer */
122  	left = (ctx->md2_total & 0xF);
123  	fill = (u16)(MD2_BLOCK_SIZE - left);
124  
125  	ctx->md2_total += ilen;
126  
127  	if ((left > 0) && (remain_ilen >= fill)) {
128  		/* Copy data at the end of the buffer */
129  		ret = local_memcpy(ctx->md2_buffer + left, data_ptr, fill); EG(ret, err);
130  		ret = md2_process(ctx, ctx->md2_buffer); EG(ret, err);
131  		data_ptr += fill;
132  		remain_ilen -= fill;
133  		left = 0;
134  	}
135  
136  	while (remain_ilen >= MD2_BLOCK_SIZE) {
137  		ret = md2_process(ctx, data_ptr); EG(ret, err);
138  		data_ptr += MD2_BLOCK_SIZE;
139  		remain_ilen -= MD2_BLOCK_SIZE;
140  	}
141  
142  	if (remain_ilen > 0) {
143  		ret = local_memcpy(ctx->md2_buffer + left, data_ptr, remain_ilen); EG(ret, err);
144  	}
145  
146  	ret = 0;
147  
148  err:
149  	return ret;
150  }
151  
152  /* Finalize. Returns 0 on success, -1 on error.*/
153  ATTRIBUTE_WARN_UNUSED_RET int md2_final(md2_context *ctx, u8 output[MD2_DIGEST_SIZE])
154  {
155  	int ret;
156  	unsigned int i;
157  	u8 pad_byte;
158  
159  	MUST_HAVE((output != NULL), ret, err);
160  	MD2_HASH_CHECK_INITIALIZED(ctx, ret, err);
161  
162  	/* This is our final step, so we proceed with the padding */
163  	pad_byte = (u8)(MD2_BLOCK_SIZE - (ctx->md2_total % MD2_BLOCK_SIZE));
164  	for(i = (ctx->md2_total % MD2_BLOCK_SIZE); i < MD2_BLOCK_SIZE; i++){
165  		ctx->md2_buffer[i] = pad_byte;
166  	}
167  	/* And process the block */
168  	ret = md2_process(ctx, ctx->md2_buffer); EG(ret, err);
169  
170  	/* Also process the checksum */
171  	ret = md2_process(ctx, ctx->md2_checksum); EG(ret, err);
172  
173  	/* Output the hash result */
174  	ret = local_memcpy(output, ctx->md2_state, MD2_DIGEST_SIZE); EG(ret, err);
175  
176  	/* Tell that we are uninitialized */
177  	ctx->magic = WORD(0);
178  
179  	ret = 0;
180  
181  err:
182  	return ret;
183  }
184  
185  
186  /*
187   * Scattered version performing init/update/finalize on a vector of buffers
188   * 'inputs' with the length of each buffer passed via 'ilens'. The function
189   * loops on pointers in 'inputs' until it finds a NULL pointer. The function
190   * returns 0 on success, -1 on error.
191   */
192  ATTRIBUTE_WARN_UNUSED_RET int md2_scattered(const u8 **inputs, const u32 *ilens,
193  		      u8 output[MD2_DIGEST_SIZE])
194  {
195  	md2_context ctx;
196  	int ret, pos = 0;
197  
198  	MUST_HAVE((inputs != NULL) && (ilens != NULL) && (output != NULL), ret, err);
199  
200  	ret = md2_init(&ctx); EG(ret, err);
201  
202  	while (inputs[pos] != NULL) {
203  		ret = md2_update(&ctx, inputs[pos], ilens[pos]); EG(ret, err);
204  		pos += 1;
205  	}
206  
207  	ret = md2_final(&ctx, output);
208  
209  err:
210  	return ret;
211  }
212  
213  /*
214   * Single call version performing init/update/final on given input.
215   * Returns 0 on success, -1 on error.
216   */
217  ATTRIBUTE_WARN_UNUSED_RET int md2(const u8 *input, u32 ilen, u8 output[MD2_DIGEST_SIZE])
218  {
219  	md2_context ctx;
220  	int ret;
221  
222  	ret = md2_init(&ctx); EG(ret, err);
223  	ret = md2_update(&ctx, input, ilen); EG(ret, err);
224  	ret = md2_final(&ctx, output);
225  
226  err:
227  	return ret;
228  }