118 lines
3.5 KiB
C
118 lines
3.5 KiB
C
/*
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* Copyright (C) 2016 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <assert.h>
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#include <stdint.h>
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#include <string.h>
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#include "expat.h"
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#include "siphash.h"
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// Macros to convert preprocessor macros to string literals. See
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// https://gcc.gnu.org/onlinedocs/gcc-3.4.3/cpp/Stringification.html
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#define xstr(s) str(s)
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#define str(s) #s
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// The encoder type that we wish to fuzz should come from the compile-time
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// definition `ENCODING_FOR_FUZZING`. This allows us to have a separate fuzzer
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// binary for
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#ifndef ENCODING_FOR_FUZZING
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# error "ENCODING_FOR_FUZZING was not provided to this fuzz target."
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#endif
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// 16-byte deterministic hash key.
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static unsigned char hash_key[16] = "FUZZING IS FUN!";
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static void XMLCALL
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start(void *userData, const XML_Char *name, const XML_Char **atts) {
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(void)userData;
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(void)name;
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(void)atts;
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}
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static void XMLCALL
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end(void *userData, const XML_Char *name) {
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(void)userData;
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(void)name;
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}
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static void XMLCALL
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may_stop_character_handler(void *userData, const XML_Char *s, int len) {
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XML_Parser parser = (XML_Parser)userData;
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if (len > 1 && s[0] == 's') {
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XML_StopParser(parser, s[1] == 'r' ? XML_FALSE : XML_TRUE);
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}
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}
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static void
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ParseOneInput(XML_Parser p, const uint8_t *data, size_t size) {
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// Set the hash salt using siphash to generate a deterministic hash.
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struct sipkey *key = sip_keyof(hash_key);
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XML_SetHashSalt(p, (unsigned long)siphash24(data, size, key));
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(void)sip24_valid;
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XML_SetUserData(p, p);
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XML_SetElementHandler(p, start, end);
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XML_SetCharacterDataHandler(p, may_stop_character_handler);
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void *buf = XML_GetBuffer(p, size);
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assert(buf);
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memcpy(buf, data, size);
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XML_ParseBuffer(p, size, 0);
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buf = XML_GetBuffer(p, size);
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if (buf == NULL) {
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return;
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}
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memcpy(buf, data, size);
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if (XML_ParseBuffer(p, size, 1) == XML_STATUS_ERROR) {
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XML_ErrorString(XML_GetErrorCode(p));
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}
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XML_GetCurrentLineNumber(p);
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if (size % 2) {
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XML_ParserReset(p, NULL);
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}
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}
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int
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LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
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if (size == 0)
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return 0;
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XML_Parser parentParser = XML_ParserCreate(xstr(ENCODING_FOR_FUZZING));
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assert(parentParser);
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ParseOneInput(parentParser, data, size);
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// not freed yet, but used later and freed then
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XML_Parser namespaceParser = XML_ParserCreateNS(NULL, '!');
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assert(namespaceParser);
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ParseOneInput(namespaceParser, data, size);
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XML_ParserFree(namespaceParser);
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XML_Parser externalEntityParser
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= XML_ExternalEntityParserCreate(parentParser, "e1", NULL);
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assert(externalEntityParser);
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ParseOneInput(externalEntityParser, data, size);
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XML_ParserFree(externalEntityParser);
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XML_Parser externalDtdParser
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= XML_ExternalEntityParserCreate(parentParser, NULL, NULL);
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assert(externalDtdParser);
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ParseOneInput(externalDtdParser, data, size);
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XML_ParserFree(externalDtdParser);
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// finally frees this parser which served as parent
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XML_ParserFree(parentParser);
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return 0;
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}
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