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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/*
* This target fuzzes NSS mpi against openssl bignum.
* It therefore requires openssl to be installed.
*/
#include "mpi_helper.h"
#include "mpprime.h"
#include <algorithm>
extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
// We require at least size 4 to get everything we need from data.
if (size < 4) {
return 0;
}
INIT_THREE_NUMBERS
// Make a prime of length size.
int count = 0;
mp_err res = MP_NO;
// mpp_make_prime is so slow :( use something smaller than size.
int primeLen = std::max(static_cast<int>(size / 4), 3);
uint8_t bp[primeLen];
memcpy(bp, data, primeLen);
do {
bp[0] |= 0x80; /* set high-order bit */
bp[primeLen - 1] |= 0x01; /* set low-order bit */
++count;
assert(mp_read_unsigned_octets(&b, bp, primeLen) == MP_OKAY);
} while ((res = mpp_make_prime(&b, primeLen * 8, PR_FALSE)) != MP_YES &&
count < 10);
if (res != MP_YES) {
return 0;
}
// Use the same prime in OpenSSL B
char tmp[max_size];
mp_toradix(&b, tmp, 16);
int tmpLen;
assert((tmpLen = BN_hex2bn(&B, tmp)) != 0);
// Compare with OpenSSL invmod
res = mp_invmod(&a, &b, &c);
BIGNUM *X = BN_mod_inverse(C, A, B, ctx);
if (res != MP_OKAY) {
// In case we couldn't compute the inverse, OpenSSL shouldn't be able to
// either.
assert(X == nullptr);
} else {
check_equal(C, &c, max_size);
// Check a * c mod b == 1
assert(mp_mulmod(&a, &c, &b, &c) == MP_OKAY);
bool eq = mp_cmp_d(&c, 1) == 0;
if (!eq) {
char cC[max_size];
mp_tohex(&c, cC);
std::cout << "c = " << std::hex << cC << std::endl;
}
assert(eq);
}
CLEANUP_AND_RETURN_THREE
}
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