1 /* 2 * Copyright (C) 2016 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include <assert.h> 18 #include <stdint.h> 19 20 #include "expat.h" 21 #include "siphash.h" 22 23 // Macros to convert preprocessor macros to string literals. See 24 // https://gcc.gnu.org/onlinedocs/gcc-3.4.3/cpp/Stringification.html 25 #define xstr(s) str(s) 26 #define str(s) #s 27 28 // The encoder type that we wish to fuzz should come from the compile-time 29 // definition `ENCODING_FOR_FUZZING`. This allows us to have a separate fuzzer 30 // binary for 31 #ifndef ENCODING_FOR_FUZZING 32 # error "ENCODING_FOR_FUZZING was not provided to this fuzz target." 33 #endif 34 35 // 16-byte deterministic hash key. 36 static unsigned char hash_key[16] = "FUZZING IS FUN!"; 37 38 static void XMLCALL 39 start(void *userData, const XML_Char *name, const XML_Char **atts) { 40 (void)userData; 41 (void)name; 42 (void)atts; 43 } 44 static void XMLCALL 45 end(void *userData, const XML_Char *name) { 46 (void)userData; 47 (void)name; 48 } 49 50 int 51 LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) { 52 XML_Parser p = XML_ParserCreate(xstr(ENCODING_FOR_FUZZING)); 53 assert(p); 54 55 // Set the hash salt using siphash to generate a deterministic hash. 56 struct sipkey *key = sip_keyof(hash_key); 57 XML_SetHashSalt(p, (unsigned long)siphash24(data, size, key)); 58 59 XML_SetElementHandler(p, start, end); 60 XML_Parse(p, (const XML_Char *)data, size, 0); 61 XML_Parse(p, (const XML_Char *)data, size, 1); 62 XML_ParserFree(p); 63 return 0; 64 } 65