Can't open zip with 65535 entries

[Nekto89]

fast "dirty" code for reproducing the issue. I'm not sure that I've used API properly. I'm creating zip files with 65534, 65536 and 65535 empty files inside. 65535 doesn't work for some reason. 7-zip can open result zip without any errors

#include <mz.h>
#include <mz_os.h>
#include <mz_strm.h>
#include <mz_strm_os.h>
#include <mz_zip.h>
#include <mz_zip_rw.h>

#include <cstdio>
#include <ctime>
#include <string>

int write_archive(const char* archive_filename, const std::size_t number_of_files) {
  void* zip_writer = nullptr;
  const char* path = archive_filename;
  mz_zip_writer_create(&zip_writer);
  if (mz_zip_writer_open_file(zip_writer, path, 0, 0) != MZ_OK) {
    mz_zip_writer_delete(&zip_writer);
    std::printf("Couldn't open zip for writing");
    return -1;
  }

  for (std::size_t i = 0; i < number_of_files; ++i) {
    const auto filename = std::to_string(i);

    mz_zip_file file_info = { 0 };
    file_info.filename = filename.c_str();
    file_info.modified_date = std::time(nullptr);
    file_info.version_madeby = MZ_VERSION_MADEBY;
    file_info.compression_method = MZ_COMPRESS_METHOD_STORE;
    file_info.flag = MZ_ZIP_FLAG_UTF8;

    if (mz_zip_writer_entry_open(zip_writer, &file_info) != MZ_OK) {
      std::printf("Couldn't open entry");
      return -2;
    }
    if (mz_zip_writer_entry_close(zip_writer) != MZ_OK) {
      std::printf("Couldn't close entry");
      return -3;
    }
  }

  if (mz_zip_writer_close(zip_writer) != MZ_OK) {
    std::printf("Couldn't close writer");
    return -4;
  }
  mz_zip_writer_delete(&zip_writer);
  return 0;
}

bool can_archive_be_opened(const char* path) {
  void* zip_reader = nullptr;
  void* file_stream = nullptr;

  mz_zip_reader_create(&zip_reader);
  mz_stream_os_create(&file_stream);

  auto err = mz_stream_os_open(file_stream, path, MZ_OPEN_MODE_READ);
  if (err == MZ_OK) {
    err = mz_zip_reader_open(zip_reader, file_stream);
    if (err == MZ_OK) {
      mz_zip_reader_close(zip_reader);
    }
  }
  mz_stream_os_delete(&file_stream);
  mz_zip_reader_delete(&zip_reader);
  return err == MZ_OK;
}

int main() {
  for (std::size_t i : {65534, 65536, 65535})
  {
    const auto filename = "test" + std::to_string(i) + ".zip";
    const auto write_result = write_archive(filename.c_str(), i);
    if (write_result != 0)
      return write_result;
    const auto read_result = can_archive_be_opened(filename.c_str());
    if (!read_result) {
      std::printf("Can't open %s", filename.c_str());
      return -5;
    }
  }
}

[nmoinvaz]

minizip-ng/mz_zip.c

Line 1122 in 99d3901

if (zip->cd_offset >= UINT32_MAX || zip->number_entry > UINT16_MAX) {

Should probably be:

if (zip->cd_offset >= UINT32_MAX || zip->number_entry >= UINT16_MAX) {

[Nekto89]

Isn't 65535 still valid number of files for ZIP? I thought that the problem is in reading.

[nmoinvaz]

If the value is 64k then it will read the value in the zip64 header instead.