| //===-- strstr_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 strstr implementation. |
| /// |
| //===----------------------------------------------------------------------===// |
| |
| #include "src/string/strlen.h" |
| #include "src/string/strstr.h" |
| #include <stddef.h> |
| #include <stdint.h> |
| |
| // Simple loop to compare two strings up to a size n. |
| static int simple_memcmp(const char *left, const char *right, size_t n) { |
| for (; n && *left == *right; ++left, ++right, --n) |
| ; |
| return n ? *left - *right : 0; |
| } |
| |
| // The general structure is to take the value of the first byte, set size1 to |
| // that value, and add the null terminator. size2 will then contain the rest of |
| // the bytes in data. |
| // For example, with inputs (data={2, 6, 4, 8, 0}, size=5): |
| // size1: data[0] = 2 |
| // data1: {2, 6} + '\0' = {2, 6, '\0'} |
| // size2: size - size1 = 3 |
| // data2: {4, 8, '\0'} |
| extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) { |
| // Verify the size is at least 1 and the data is null terminated. |
| if (!size || data[size - 1] != '\0') |
| return 0; |
| const size_t size1 = (data[0] <= size ? data[0] : size); |
| // The first size will always be at least 1 since |
| // we need to append the null terminator. The second size |
| // needs to be checked since it must also contain the null |
| // terminator. |
| if (size - size1 == 0) |
| return 0; |
| |
| // Copy the data into a new container. |
| uint8_t *container = new uint8_t[size1 + 1]; |
| if (!container) |
| __builtin_trap(); |
| |
| size_t i; |
| for (i = 0; i < size1; ++i) |
| container[i] = data[i]; |
| container[size1] = '\0'; // Add null terminator to container. |
| |
| const char *needle = reinterpret_cast<const char *>(container); |
| const char *haystack = reinterpret_cast<const char *>(data + i); |
| const char *result = __llvm_libc::strstr(haystack, needle); |
| |
| // A null terminator may exist earlier in each, so this needs to be recorded. |
| const size_t haystack_size = __llvm_libc::strlen(haystack); |
| const size_t needle_size = __llvm_libc::strlen(needle); |
| |
| if (result) { |
| // The needle is in the haystack. |
| // 1. Verify that the result matches the needle. |
| if (simple_memcmp(needle, result, needle_size) != 0) |
| __builtin_trap(); |
| |
| const char *haystack_ptr = haystack; |
| // 2. Verify that the result is the first occurrence of the needle. |
| for (; haystack_ptr != result; ++haystack_ptr) { |
| if (simple_memcmp(needle, haystack_ptr, needle_size) == 0) |
| __builtin_trap(); // There was an earlier occurrence of the needle. |
| } |
| } else { |
| // No result was found. Verify that the needle doesn't exist within the |
| // haystack. |
| for (size_t i = 0; i + needle_size < haystack_size; ++i) { |
| if (simple_memcmp(needle, haystack + i, needle_size) == 0) |
| __builtin_trap(); // There was an earlier occurrence of the needle. |
| } |
| } |
| delete[] container; |
| return 0; |
| } |