[libc-commits] [libc] [libc] Add memcmp / bcmp fuzzers (PR #77741)
Clement Courbet via libc-commits
libc-commits at lists.llvm.org
Thu Jan 11 01:55:08 PST 2024
================
@@ -0,0 +1,52 @@
+//===-- bcmp_fuzz.cpp ---------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// Fuzzing test for llvm-libc bcmp implementation.
+///
+//===----------------------------------------------------------------------===//
+#include "src/string/bcmp.h"
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+static int reference_bcmp(const void *pa, const void *pb, size_t count)
+ __attribute__((no_builtin)) {
+ const auto *a = reinterpret_cast<const unsigned char *>(pa);
+ const auto *b = reinterpret_cast<const unsigned char *>(pb);
+ for (size_t i = 0; i < count; ++i, ++a, ++b)
+ if (*a != *b)
+ return 1;
+ return 0;
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+ const auto normalize = [](int value) -> int {
+ if (value == 0)
+ return 0;
+ return 1;
+ };
+ const auto count = size / 2;
+ const char *a = reinterpret_cast<const char *>(data);
+ const char *b = reinterpret_cast<const char *>(data) + count;
+ const int actual = LIBC_NAMESPACE::bcmp(a, b, count);
+ const int reference = reference_bcmp(a, b, count);
+ if (normalize(actual) == normalize(reference))
+ return 0;
+ const auto print = [](const char *msg, const char *buffer, size_t size) {
+ printf("%s\"", msg);
+ for (size_t i = 0; i < size; ++i)
+ printf("\\x%02x", (uint8_t)buffer[i]);
+ printf("\"\n");
+ };
+ print("a : ", a, count);
+ print("b : ", b, count);
+ printf("count : %zu\n", count);
----------------
legrosbuffle wrote:
Nit: print count first ?
https://github.com/llvm/llvm-project/pull/77741
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