Bug 1334106 - split mpi target, r=ttaubert

Differential Revision: https://nss-review.dev.mozaws.net/D189

1 files changed, 51 insertions, 0 deletions

diff --git a/fuzz/mpi_sqrmod_target.cc b/fuzz/mpi_sqrmod_target.cc
new file mode 100644
index 000000000..d3886dacd
--- /dev/null
+++ b/fuzz/mpi_sqrmod_target.cc
@@ -0,0 +1,51 @@
+/* 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"
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+  // We require at least size 3 to get two integers from Data.
+  if (size < 3) {
+    return 0;
+  }
+  mp_int a, b, c;
+  BN_CTX *ctx = BN_CTX_new();
+  BN_CTX_start(ctx);
+  BIGNUM *A = BN_CTX_get(ctx);
+  BIGNUM *B = BN_CTX_get(ctx);
+  BIGNUM *C = BN_CTX_get(ctx);
+  assert(mp_init(&a) == MP_OKAY);
+  assert(mp_init(&b) == MP_OKAY);
+  assert(mp_init(&c) == MP_OKAY);
+  size_t max_size = 4 * size + 1;
+  parse_input(data, size, A, &a);
+
+  // We can't divide by 0.
+  if (mp_cmp_z(&b) == 0) {
+    mp_clear(&a);
+    mp_clear(&b);
+    mp_clear(&c);
+    BN_CTX_end(ctx);
+    BN_CTX_free(ctx);
+    return 0;
+  }
+
+  // Compare with OpenSSL square mod
+  assert(mp_sqrmod(&a, &b, &c) == MP_OKAY);
+  (void)BN_mod_sqr(C, A, B, ctx);
+  check_equal(C, &c, max_size);
+
+  mp_clear(&a);
+  mp_clear(&b);
+  mp_clear(&c);
+  BN_CTX_end(ctx);
+  BN_CTX_free(ctx);
+
+  return 0;
+}