1 //===-- strcmp_fuzz.cpp ---------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 /// 9 /// Fuzzing test for llvm-libc strcmp implementation. 10 /// 11 //===----------------------------------------------------------------------===// 12 #include "src/string/strcmp.h" 13 #include <algorithm> 14 #include <stdint.h> 15 16 extern "C" int LLVMFuzzerTestTwoInputs(const uint8_t *data1, size_t size1, 17 const uint8_t *data2, size_t size2) { 18 // Verify each data source contains at least one character. 19 if (!size1 || !size2) 20 return 0; 21 // Verify that the final character is the null terminator. 22 if (data1[size1 - 1] != '\0' || data2[size2 - 1] != '\0') 23 return 0; 24 25 const char *s1 = reinterpret_cast<const char *>(data1); 26 const char *s2 = reinterpret_cast<const char *>(data2); 27 28 const size_t minimum_size = std::min(size1, size2); 29 30 // Iterate through until either the minimum size is hit, 31 // a character is the null terminator, or the first set 32 // of differed bytes between s1 and s2 are found. 33 // No bytes following a null byte should be compared. 34 size_t i; 35 for (i = 0; i < minimum_size && s1[i] && s1[i] == s2[i]; ++i) 36 ; 37 38 int expected_result = s1[i] - s2[i]; 39 int actual_result = __llvm_libc::strcmp(s1, s2); 40 41 // The expected result should be the difference between the first non-equal 42 // characters of s1 and s2. If all characters are equal, the expected result 43 // should be '\0' - '\0' = 0. 44 if (expected_result != actual_result) 45 __builtin_trap(); 46 47 // Verify reversed operands. This should be the negated value of the previous 48 // result, except of course if the previous result was zero. 49 expected_result = s2[i] - s1[i]; 50 actual_result = __llvm_libc::strcmp(s2, s1); 51 if (expected_result != actual_result) 52 __builtin_trap(); 53 54 return 0; 55 } 56