e455e6c9ec
This patch adds the `strnlen_s` function from Annex K. In order to reduce duplication between `strnlen` and `strnlen_s`, the common logic has been extracted to a new internal function which both now call. In addition to the function definition, the patch adds a unit test and a fuzzing test.
60 lines
1.9 KiB
C++
60 lines
1.9 KiB
C++
//===-- strnlen_s_differential_fuzz.cpp -----------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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///
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/// Differential fuzz test for llvm-libc strnlen_s implementation.
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///
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//===----------------------------------------------------------------------===//
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#define __STDC_WANT_LIB_EXT1__ 1
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#include "src/string/strnlen_s.h"
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#include <stdint.h>
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#include <string.h>
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extern "C" size_t LLVMFuzzerMutate(uint8_t *data, size_t size, size_t max_size);
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extern "C" size_t LLVMFuzzerCustomMutator(uint8_t *data, size_t size,
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size_t max_size,
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unsigned int /*seed*/) {
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// The buffer is constructed as follows:
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// data = max_len (size_t) + null-terminated string
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if (max_size < sizeof(size_t) + 1)
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return size;
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do {
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size = LLVMFuzzerMutate(data, size, max_size);
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} while (size < sizeof(size_t) + 1);
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data[size - 1] = '\0';
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return size;
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}
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extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
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if (size < sizeof(size_t) + 1)
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return 0;
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size_t max_len;
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::memcpy(&max_len, data, sizeof(size_t));
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data += sizeof(size_t);
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// If Annex K is not available in the system's C library, we compare against
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// strnlen instead. We can assume this is valid because in the case where the
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// input string is not null, the two functions must have identical semantics.
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#ifdef __STDC_LIB_EXT1__
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size_t ref = ::strnlen_s(reinterpret_cast<const char *>(data), max_len);
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#else
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size_t ref = ::strnlen(reinterpret_cast<const char *>(data), max_len);
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#endif
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size_t impl =
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LIBC_NAMESPACE::strnlen_s(reinterpret_cast<const char *>(data), max_len);
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if (ref != impl)
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__builtin_trap();
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return 0;
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}
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