kc3-lang/libxml2/fuzz/regexp.c

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• Hash : c6c6d8af
  Author :
  Date : 2024-12-11T16:24:23
  

  fuzz: Mutate fuzz data chunks separately
  
  Implement a custom mutator that takes a list of fixed-size chunks which
  are mutated with a given probability. This makes sure that values like
  parser options or failure position are mutated regularly even as the
  fuzz data grows large. Values can also be adjusted temporarily to make
  the fuzzer focus on failure injection, for example.
  
  Thanks to David Kilzer for the idea.
  

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• fuzz/regexp.c

• /*
   * regexp.c: a libFuzzer target to test the regexp module.
   *
   * See Copyright for the status of this software.
   */
  
  #include <stdio.h>
  #include <stdlib.h>
  #include <libxml/xmlregexp.h>
  #include "fuzz.h"
  
  int
  LLVMFuzzerInitialize(int *argc ATTRIBUTE_UNUSED,
                       char ***argv ATTRIBUTE_UNUSED) {
      xmlFuzzMemSetup();
  
      return 0;
  }
  
  int
  LLVMFuzzerTestOneInput(const char *data, size_t size) {
      xmlRegexpPtr regexp;
      size_t failurePos;
      const char *str1;
  
      if (size > 200)
          return(0);
  
      xmlFuzzDataInit(data, size);
      failurePos = xmlFuzzReadInt(4) % (size * 8 + 100);
      str1 = xmlFuzzReadString(NULL);
  
      xmlFuzzInjectFailure(failurePos);
      regexp = xmlRegexpCompile(BAD_CAST str1);
      if (xmlFuzzMallocFailed() && regexp != NULL) {
          fprintf(stderr, "malloc failure not reported\n");
          abort();
      }
      /* xmlRegexpExec has pathological performance in too many cases. */
  #if 0
      xmlRegexpExec(regexp, BAD_CAST str2);
  #endif
      xmlRegFreeRegexp(regexp);
  
      xmlFuzzInjectFailure(0);
      xmlFuzzDataCleanup();
      xmlResetLastError();
  
      return 0;
  }
  
  size_t
  LLVMFuzzerCustomMutator(char *data, size_t size, size_t maxSize,
                          unsigned seed) {
      static const xmlFuzzChunkDesc chunks[] = {
          { 4, XML_FUZZ_PROB_ONE / 10 }, /* failurePos */
          { 0, 0 }
      };
  
      return xmlFuzzMutateChunks(chunks, data, size, maxSize, seed,
                                 LLVMFuzzerMutate);
  }
  
  

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