/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying

   file LICENSE.rst or https://cmake.org/licensing for details.  */

/*

 * Fuzzer for CMake's archive extraction (tar/zip)

 *

 * CMake extracts archives via cmSystemTools::ExtractTar. This is a critical

 * attack surface as malicious archives could contain path traversal sequences

 * (Zip Slip) or other exploits.

 *

 * Coverage targets:

 * - Archive format detection (tar, gzip, bzip2, xz, zip)

 * - Path handling during extraction

 * - Symlink handling

 * - Large file handling

 * - Malformed archive recovery

 *

 * Security focus:

 * - Path traversal (../) detection

 * - Absolute path handling

 * - Symlink escape attempts

 */

#include <cstddef>

#include <cstdint>

#include <cstdio>

#include <cstdlib>

#include <string>

#include <vector>

#include "cmSystemTools.h"

// Archives can be large but limit for fuzzing

static constexpr size_t kMinInputSize = 4;          // Minimum magic bytes

static constexpr size_t kMaxInputSize = 256 * 1024; // 256KB

// Sandbox directory for extraction

static std::string g_extractDir;

extern "C" int LLVMFuzzerInitialize(int* argc, char*** argv)

{

  (void)argc;

  (void)argv;

  // Create a unique extraction directory in /tmp

  char tmpl[] = "/tmp/cmake_fuzz_extract_XXXXXX";

  char* dir = mkdtemp(tmpl);

  if (dir) {

    g_extractDir = dir;

  } else {

    g_extractDir = "/tmp/cmake_fuzz_extract";

    cmSystemTools::MakeDirectory(g_extractDir);

  }

  return 0;

}

extern "C" int LLVMFuzzerTestOneInput(uint8_t const* data, size_t size)

{

  if (size < kMinInputSize || size > kMaxInputSize) {

    return 0;

  }

  // Write archive to temp file

  std::string archiveFile = g_extractDir + "/test_archive";

  {

    FILE* fp = fopen(archiveFile.c_str(), "wb");

    if (!fp) {

      return 0;

    }

    fwrite(data, 1, size, fp);

    fclose(fp);

  }

  // Create a fresh extraction subdirectory each time

  std::string extractSubDir = g_extractDir + "/out";

  cmSystemTools::RemoveADirectory(extractSubDir);

  cmSystemTools::MakeDirectory(extractSubDir);

  // Save current directory

  std::string cwd = cmSystemTools::GetCurrentWorkingDirectory();

  // Change to extraction directory (cmSystemTools extracts to cwd)

  if (cmSystemTools::ChangeDirectory(extractSubDir)) {

    // Try extraction with different options

    std::vector<std::string> files;

    // Extract without verbose, with timestamps

    bool result1 = cmSystemTools::ExtractTar(

      archiveFile, files, cmSystemTools::cmTarExtractTimestamps::Yes, false);

    (void)result1;

    // Restore directory BEFORE removing (can't remove cwd)

    cmSystemTools::ChangeDirectory(cwd);

    // Clean up extracted files

    cmSystemTools::RemoveADirectory(extractSubDir);

    cmSystemTools::MakeDirectory(extractSubDir);

    // Change back for second extraction

    if (cmSystemTools::ChangeDirectory(extractSubDir)) {

      // Extract with verbose, without timestamps

      files.clear();

      bool result2 = cmSystemTools::ExtractTar(

        archiveFile, files, cmSystemTools::cmTarExtractTimestamps::No, true);

      (void)result2;

      // Restore directory

      cmSystemTools::ChangeDirectory(cwd);

    }

  }

  // Note: A more thorough security check would verify nothing escaped the

  // sandbox, but for fuzzing we rely on sanitizers to catch path traversal

  // Cleanup

  cmSystemTools::RemoveADirectory(extractSubDir);

  cmSystemTools::RemoveFile(archiveFile);

  return 0;

}