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			131 lines
		
	
	
	
		
			3.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			131 lines
		
	
	
	
		
			3.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.
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|  *
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|  * Licensed under the OpenSSL licenses, (the "License");
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|  * you may not use this file except in compliance with the License.
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|  * You may obtain a copy of the License at
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|  * https://www.openssl.org/source/license.html
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|  * or in the file LICENSE in the source distribution.
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|  */
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| 
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| /*
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|  * Confirm that if (d, r) = a / b, then b * d + r == a, and that sign(d) ==
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|  * sign(a), and 0 <= r <= b
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|  */
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| 
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| #include <stdio.h>
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| #include <openssl/bn.h>
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| #include <openssl/err.h>
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| #include "fuzzer.h"
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| 
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| /* 256 kB */
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| #define MAX_LEN (256 * 1000)
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| 
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| static BN_CTX *ctx;
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| static BIGNUM *b1;
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| static BIGNUM *b2;
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| static BIGNUM *b3;
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| static BIGNUM *b4;
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| static BIGNUM *b5;
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| 
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| int FuzzerInitialize(int *argc, char ***argv)
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| {
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|     b1 = BN_new();
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|     b2 = BN_new();
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|     b3 = BN_new();
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|     b4 = BN_new();
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|     b5 = BN_new();
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|     ctx = BN_CTX_new();
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| 
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|     OPENSSL_init_crypto(OPENSSL_INIT_LOAD_CRYPTO_STRINGS, NULL);
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|     ERR_get_state();
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| 
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|     return 1;
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| }
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| 
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| int FuzzerTestOneInput(const uint8_t *buf, size_t len)
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| {
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|     int success = 0;
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|     size_t l1 = 0, l2 = 0;
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|     /* s1 and s2 will be the signs for b1 and b2. */
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|     int s1 = 0, s2 = 0;
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| 
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|     /* limit the size of the input to avoid timeout */
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|     if (len > MAX_LEN)
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|         len = MAX_LEN;
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| 
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|     /* We are going to split the buffer in two, sizes l1 and l2, giving b1 and
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|      * b2.
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|      */
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|     if (len > 0) {
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|         --len;
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|         /* Use first byte to divide the remaining buffer into 3Fths. I admit
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|          * this disallows some number sizes. If it matters, better ideas are
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|          * welcome (Ben).
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|          */
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|         l1 = ((buf[0] & 0x3f) * len) / 0x3f;
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|         s1 = buf[0] & 0x40;
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|         s2 = buf[0] & 0x80;
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|         ++buf;
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|         l2 = len - l1;
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|     }
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|     OPENSSL_assert(BN_bin2bn(buf, l1, b1) == b1);
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|     BN_set_negative(b1, s1);
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|     OPENSSL_assert(BN_bin2bn(buf + l1, l2, b2) == b2);
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|     BN_set_negative(b2, s2);
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| 
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|     /* divide by 0 is an error */
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|     if (BN_is_zero(b2)) {
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|         success = 1;
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|         goto done;
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|     }
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| 
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|     OPENSSL_assert(BN_div(b3, b4, b1, b2, ctx));
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|     if (BN_is_zero(b1))
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|         success = BN_is_zero(b3) && BN_is_zero(b4);
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|     else if (BN_is_negative(b1))
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|         success = (BN_is_negative(b3) != BN_is_negative(b2) || BN_is_zero(b3))
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|             && (BN_is_negative(b4) || BN_is_zero(b4));
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|     else
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|         success = (BN_is_negative(b3) == BN_is_negative(b2)  || BN_is_zero(b3))
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|             && (!BN_is_negative(b4) || BN_is_zero(b4));
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|     OPENSSL_assert(BN_mul(b5, b3, b2, ctx));
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|     OPENSSL_assert(BN_add(b5, b5, b4));
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| 
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|     success = success && BN_cmp(b5, b1) == 0;
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|     if (!success) {
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|         BN_print_fp(stdout, b1);
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|         putchar('\n');
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|         BN_print_fp(stdout, b2);
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|         putchar('\n');
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|         BN_print_fp(stdout, b3);
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|         putchar('\n');
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|         BN_print_fp(stdout, b4);
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|         putchar('\n');
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|         BN_print_fp(stdout, b5);
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|         putchar('\n');
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|         printf("%d %d %d %d %d %d %d\n", BN_is_negative(b1),
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|                BN_is_negative(b2),
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|                BN_is_negative(b3), BN_is_negative(b4), BN_is_zero(b4),
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|                BN_is_negative(b3) != BN_is_negative(b2)
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|                && (BN_is_negative(b4) || BN_is_zero(b4)),
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|                BN_cmp(b5, b1));
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|         puts("----\n");
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|     }
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| 
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|  done:
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|     OPENSSL_assert(success);
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|     ERR_clear_error();
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| 
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|     return 0;
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| }
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| 
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| void FuzzerCleanup(void)
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| {
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|     BN_free(b1);
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|     BN_free(b2);
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|     BN_free(b3);
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|     BN_free(b4);
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|     BN_free(b5);
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|     BN_CTX_free(ctx);
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| }
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