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/* Copyright (c) 2017, Google Inc.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
#include <openssl/bn.h>
#include <openssl/bytestring.h>
#include <openssl/span.h>
#define CHECK(expr) \
do { \
if (!(expr)) { \
printf("%s failed\n", #expr); \
abort(); \
} \
} while (false)
extern "C" int LLVMFuzzerTestOneInput(const uint8_t *buf, size_t len) {
CBS cbs, child0, child1;
uint8_t sign0, sign1;
CBS_init(&cbs, buf, len);
if (!CBS_get_u16_length_prefixed(&cbs, &child0) ||
!CBS_get_u8(&child0, &sign0) ||
CBS_len(&child0) == 0 ||
!CBS_get_u16_length_prefixed(&cbs, &child1) ||
!CBS_get_u8(&child1, &sign1) ||
CBS_len(&child1) == 0) {
return 0;
}
bssl::UniquePtr<BIGNUM> numerator(
BN_bin2bn(CBS_data(&child0), CBS_len(&child0), nullptr));
BN_set_negative(numerator.get(), sign0 % 2);
bssl::UniquePtr<BIGNUM> divisor(
BN_bin2bn(CBS_data(&child1), CBS_len(&child1), nullptr));
BN_set_negative(divisor.get(), sign1 % 2);
if (BN_is_zero(divisor.get())) {
return 0;
}
bssl::UniquePtr<BN_CTX> ctx(BN_CTX_new());
bssl::UniquePtr<BIGNUM> result(BN_new());
bssl::UniquePtr<BIGNUM> remainder(BN_new());
CHECK(ctx);
CHECK(result);
CHECK(remainder);
CHECK(BN_div(result.get(), remainder.get(), numerator.get(), divisor.get(),
ctx.get()));
CHECK(BN_ucmp(remainder.get(), divisor.get()) < 0);
// Check that result*divisor+remainder = numerator.
CHECK(BN_mul(result.get(), result.get(), divisor.get(), ctx.get()));
CHECK(BN_add(result.get(), result.get(), remainder.get()));
CHECK(BN_cmp(result.get(), numerator.get()) == 0);
return 0;
}
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