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/*
* (C) 2021 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include "fuzzers.h"
#include <botan/numthry.h>
namespace {
Botan::BigInt ref_gcd(Botan::BigInt a, Botan::BigInt b) {
Botan::BigInt t;
while(b != 0) {
t = a % b;
t.swap(b);
t.swap(a);
}
return a;
}
} // namespace
void fuzz(std::span<const uint8_t> in) {
static const size_t max_bits = 4096;
if(2 * in.size() * 8 > max_bits) {
return;
}
const Botan::BigInt x = Botan::BigInt::from_bytes(in.subspan(in.size() / 2));
const Botan::BigInt y = Botan::BigInt::from_bytes(in.subspan(in.size() / 2, in.size() - (in.size() / 2)));
const Botan::BigInt ref = ref_gcd(x, y);
const Botan::BigInt lib = Botan::gcd(x, y);
if(ref != lib) {
FUZZER_WRITE_AND_CRASH("X = " << x.to_hex_string() << "\n"
<< "Y = " << y.to_hex_string() << "\n"
<< "L = " << lib.to_hex_string() << "\n"
<< "R = " << ref.to_hex_string() << "\n");
}
}