diff options
author | Ben Laurie <ben@links.org> | 2016-03-26 17:19:14 +0000 |
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committer | Ben Laurie <ben@links.org> | 2016-05-07 18:13:54 +0100 |
commit | c38bb72797916f2a0ab9906aad29162ca8d53546 (patch) | |
tree | e3df72e2e4c4d14a822cd0a3101d005a8923a929 /fuzz/bignum.c | |
parent | 049f5bbce3eebdf4ec2030042eb2ae64bb67aedb (diff) |
Add fuzzing!
Reviewed-by: Emilia Käsper <emilia@openssl.org>
Diffstat (limited to 'fuzz/bignum.c')
-rw-r--r-- | fuzz/bignum.c | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/fuzz/bignum.c b/fuzz/bignum.c new file mode 100644 index 0000000000..28a439e7d7 --- /dev/null +++ b/fuzz/bignum.c @@ -0,0 +1,91 @@ +/* + * Copyright 2016 The OpenSSL Project Authors. All Rights Reserved. + * + * Licensed under the OpenSSL licenses, (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * https://www.openssl.org/source/license.html + * or in the file LICENSE in the source distribution. + */ + +/* + * Confirm that a^b mod c agrees when calculated cleverly vs naively, for + * random a, b and c. + */ + +#include <stdio.h> +#include <openssl/bn.h> +#include "fuzzer.h" + +int LLVMFuzzerTestOneInput(const uint8_t *buf, size_t len) { + int success = 0; + static BN_CTX *ctx; + static BN_MONT_CTX *mont; + static BIGNUM *b1; + static BIGNUM *b2; + static BIGNUM *b3; + static BIGNUM *b4; + static BIGNUM *b5; + + if (ctx == NULL) { + b1 = BN_new(); + b2 = BN_new(); + b3 = BN_new(); + b4 = BN_new(); + b5 = BN_new(); + ctx = BN_CTX_new(); + mont = BN_MONT_CTX_new(); + } + // Divide the input into three parts, using the values of the first two + // bytes to choose lengths, which generate b1, b2 and b3. Use three bits + // of the third byte to choose signs for the three numbers. + size_t l1 = 0, l2 = 0, l3 = 0; + int s1 = 0, s2 = 0, s3 = 0; + if (len > 2) { + len -= 3; + l1 = (buf[0] * len) / 255; + ++buf; + l2 = (buf[0] * (len - l1)) / 255; + ++buf; + l3 = len - l1 - l2; + + s1 = buf[0] & 1; + s2 = buf[0] & 2; + s3 = buf[0] & 4; + ++buf; + } + OPENSSL_assert(BN_bin2bn(buf, l1, b1) == b1); + BN_set_negative(b1, s1); + OPENSSL_assert(BN_bin2bn(buf + l1, l2, b2) == b2); + BN_set_negative(b2, s2); + OPENSSL_assert(BN_bin2bn(buf + l1 + l2, l3, b3) == b3); + BN_set_negative(b3, s3); + + // mod 0 is undefined + if (BN_is_zero(b3)) { + success = 1; + goto done; + } + + OPENSSL_assert(BN_mod_exp(b4, b1, b2, b3, ctx)); + OPENSSL_assert(BN_mod_exp_simple(b5, b1, b2, b3, ctx)); + + success = BN_cmp(b4, b5) == 0; + if (!success) { + BN_print_fp(stdout, b1); + putchar('\n'); + BN_print_fp(stdout, b2); + putchar('\n'); + BN_print_fp(stdout, b3); + putchar('\n'); + BN_print_fp(stdout, b4); + putchar('\n'); + BN_print_fp(stdout, b5); + putchar('\n'); + } + + done: + OPENSSL_assert(success); + + return 0; +} |