Zipper is a C++11 wrapper around minizip compression library. Its goal is to bring the power and simplicity of minizip to a more object-oriented/c++ user-friendly library. Note: We are currently using C++14 because the unit tests library needs it.

This project is the continuation of the original project. The original project was born out of the necessity of a compression library that would be reliable, simple, and flexible. By flexibility I mean supporting all kinds of inputs and outputs, but specifically being able to compress into memory instead of being restricted to file compression only, and using data from memory instead of just files as well.

This current fork repo has been made because the original project was no longer maintained by the original authors and I, Lecrapouille, have some issues due to missing administration rights (needed for CI, branch management ...).

Zipper Features

• Create zip in memory.
• Allow files, vectors, and generic streams as input to zip.
• File mappings for replacing strategies (overwrite if exists or use alternative names from mapping).
• Password-protected zip (EAS).
• Multi-platform.
• Project compiled as static and dynamic libraries.
• Protection against the Zip Slip attack.
• Non-regression tests.

⚠️ Security Notice

• Zipper currently follows an outdated (and probably vulnerable) version of the https://github.com/Lecrapouille/minizip library: SHA1 0bb5afeb0d3f23149b086ccda7e4fee7d48f4fdf of https://github.com/zlib-ng/minizip-ng which dated of 2017).
• While some fixes have been added this lib may be still vulnerable to ZipSlip attacks and mitigations should be put in place by Zipper's users.

Getting Started

Compiling / Installing

To download the project and compile it:

git clone https://github.com/lecrapouille/zipper.git --recursive
cd zipper
# Optionally: make download-external-libs
make compile-external-libs
make -j`nproc --all`
# make -j`sysctl -n hw.logicalcpu` for MacOS X

Notes:

• Git cloning needs the recursivity option to install the Makefile helper and third-part libs (zlib and minizip). They are based on fixed SHA1.
• Optionaly make download-external-libs will git clone HEADs of zlib and minizip to the external folder. This replaces git submodules.
• make compile-external-libs will compile zlib and minizip but not install them on your operating system. They are compiled as static libraries and merged into this library.

Installing C++ header files and compiled libraries, type:

sudo make install

For Linux, you will see a message like:

*** Installing: doc => /usr/share/Zipper/2.0.0/doc
*** Installing: libs => /usr/lib
*** Installing: pkg-config => /usr/lib/pkgconfig
*** Installing: headers => /usr/include/Zipper-2.0.0
*** Installing: Zipper => /usr/include/Zipper-2.0.0

Optionally, you can compile demos present in the folder doc/demos:

make demos -j8

See their README files for their usage.

Linking Zipper to your project

• In your project add the needed headers in your c++ files:

#include <Zipper/Unzipper.hpp>
#include <Zipper/Zipper.hpp>

• To compile your project against Zipper use pkg-config:

g++ -W -Wall --std=c++11 main.cpp -o prog `pkg-config zipper --cflags --libs`

• For Makefile:

  • set LDFLAGS to pkg-config zipper --libs
  • set CPPFLAGS to pkg-config zipper --cflags

• For CMake:

include(FindPkgConfig)
find_package(zipper)

API

There are two classes available Zipper and Unzipper. They behave in the same manner regarding constructors and storage parameters.

Zipping API

Header

#include <Zipper/Zipper.hpp>
using namespace zipper;

Constructor

• Constructor without password and replace ziptest.zip if already present. The new zip archive is dummy.

Zipper zipper("ziptest.zip", Zipper::openFlags::Overwrite);
// Or simply: zipper("ziptest.zip");

• Constructor without password and preserve ziptest.zip if already present.

Zipper zipper("ziptest.zip", Zipper::openFlags::Append);

• Constructor with password (using AES algorithm) and replace ziptest.zip if already present. The new zip archive is dummy.

Zipper zipper("ziptest.zip", "mypassword", Zipper::openFlags::Overwrite);
// Or simply: zipper("ziptest.zip");

• Constructor with a password and preserve ziptest.zip if already present.

Zipper zipper("ziptest.zip", "mypassword", Zipper::openFlags::Append);

• Note: all constructors will throw std::run_time exception in case of failure.

try
{
    Zipper zipper("ziptest.zip", ...);
    ...
}
catch (std::run_time const& e)
{
    std::cerr << e.what() << std::endl;
}

Destructor / closing / reopening

Do not forget to call explicitly close() (called implicitly from its destructor) else the zip will not be well formed and Unzipper will fail to open it for example.

Zipper zipper("ziptest.zip", ...);
...
zipper.close(); // Now Unzipper unzipper("ziptest.zip") can work

After close() you can reopen the zip archive with open(). The implicit option Zipper::openFlags::Append is to preserve the zip content. To replace the zip file is to use Zipper::openFlags::Overwrite.

Zipper zipper("ziptest.zip", ...);
...
zipper.close();
...

zipper.open(); // equivalent to zipper.open(Zipper::openFlags::Append);
// or zipper.open(Zipper::openFlags::Overwrite);
...
zipper.close();

In case of success the open() will return true else will return false and the error() should be used for getting the std::error_code.

if (!zipper.open())
{
    std::cerr << zipper.error().message() << std::endl;
}

Appending files or folders inside the archive.

The add() method allows appending files or folders. The Zipper::zipFlags::Better is set implicitly. Other options are (in the last option in the arguments):

• Store only: Zipper::zipFlags::Store.
• Compress faster, less compressed: Zipper::zipFlags::Faster.
• Compress intermediate time/compression: Zipper::zipFlags::Medium.
• Compress faster better: Zipper::zipFlags::Better.

In case of success the open() will return true else will return false and the error() should be used for getting the std::error_code.

• Adding an entire folder to a zip:

Zipper zipper("ziptest.zip");
zipper.add("myFolder/");
zipper.close();

• Adding a file by name:

Zipper zipper("ziptest.zip");
zipper.add("somefile.txt");
zipper.close();

• You can change their name in the archive:

Zipper zipper("ziptest.zip");
zipper.add("somefile.txt", "new_name_in_archive");
zipper.close();

• Create a zip file with 2 files referred by their std::ifstream and change their name in the archive:

std::ifstream input1("first_file");
std::ifstream input2("second_file");

Zipper zipper("ziptest.zip");
zipper.add(input1, "Test1");
zipper.add(input2, "Test2");
zipper.close();

• Zipper has security against Zip Slip vulnerability.

zipper.add(input1, "../Test1");

Will always return false because Test1 will be extracted outside the destination folder. This prevents malicious attack from replacing your password files:

zipper.add(malicious_passwd, "../../../../../../../../../../../../../../../etc/passwd");

Becase in Unix try to go outside the root folder / will stay in the root folder. Example

cd /
pwd
cd ../../../../../../../../../../../../../../..
pwd

• The Zipper lib force canonical paths in the archive. The following code works (will return true):

zipper.add(input1, "foo/../Test1");

because foo/../Test1 is replaced by Test1 (even if the folder foo is not present in the zip archive.

Vector and stream

• Creating a zip file using the awesome streams from the boost library that lets us use a vector as a stream:

#include <boost/interprocess/streams/vectorstream.hpp>
...

boost::interprocess::basic_vectorstream<std::vector<char>> input_data(some_vector);

Zipper zipper("ziptest.zip");
zipper.add(input_data, "Test1");
zipper.close();

• Creating a zip in a vector with files:

#include <boost/interprocess/streams/vectorstream.hpp>
...

boost::interprocess::basic_vectorstream<std::vector<char>> zip_in_memory;
std::ifstream input1("some file");

Zipper zipper(zip_in_memory); // You can pass password
zipper.add(input1, "Test1");
zipper.close();

zipper::Unzipper unzipper(zip_in_memory);
unzipper.extractEntry(...

Or:

#include <vector>

std::vector<unsigned char> zip_vect;
std::ifstream input1("some file");

Zipper zipper(zip_vect); // You can pass password
zipper.add(input1, "Test1");
zipper.close();

• Creating a zip in-memory stream with files:

std::stringstream ss;
std::ifstream input1("some file");

Zipper zipper(ss); // You can pass password
zipper.add(input1, "Test1");
zipper.close();

zipper::Unzipper unzipper(ss);
unzipper.extractEntry(...

Unzipping API

Header

#include <Zipper/Unzipper.hpp>
using namespace zipper;

Constructor

• Constructor without password and opening ziptest.zip (shall be already present).

Zipper unzipper("ziptest.zip");
...
zipper.close();

• Constructor with a password and opening ziptest.zip (shall be already present).

Zipper unzipper("ziptest.zip", "mypassword");
...
zipper.close();

• Note: all constructors will throw std::run_time exception in case of failure.

try
{
    Zipper zipper("ziptest.zip", ...);
    ...
}
catch (std::run_time const& e)
{
    std::cerr << e.what() << std::endl;
}

Getting the list of zip entries

Unzipper unzipper("zipfile.zip");
std::vector<ZipEntry> entries = unzipper.entries();
for (auto& it: unzipper.entries())
{
    std::cout << it.name << ": "
              << it.timestamp
              << std::endl;
}
unzipper.close();

Extracting all entries from the zip file

Two methods extract() for the whole archive and extractEntry() for a single element in the archive. They return true in case of success or false in case of failure. In case of failure, use unzipper.error(); to get the std::error_code.

• If you do not care about replacing existing files or folders:

Unzipper unzipper("zipfile.zip");
unzipper.extractAll(true);
unzipper.close();

• If you care about replacing existing files or folders. The method will fail (return false) if a file is replaced.

Unzipper unzipper("zipfile.zip");
unzipper.extractAll(); // equivalent to unzipper.extractAll(false);
unzipper.close();

• Extracting all entries from the zip file to the desired destination:

Unzipper unzipper("zipfile.zip");
unzipper.extractAll("/the/destination/path");        // Fail if a file exists (false argument is implicit)
unzipper.extractAll("/the/destination/path", true);  // Replace existing files
unzipper.close();

• Extracting all entries from the zip file using alternative names for existing files on disk:

std::map<std::string, std::string> alternativeNames = { {"Test1", "alternative_name_test1"} };
Unzipper unzipper("zipfile.zip");
unzipper.extractAll(".", alternativeNames);
unzipper.close();

• Extracting a single entry from the zip file:

Unzipper unzipper("zipfile.zip");
unzipper.extractEntry("entry name");
unzipper.close();

Return true in case of success or false in case of failure. In case of failure, use unzipper.error(); to get the std::error_code.

• Extracting a single entry from the zip file to destination:

Unzipper unzipper("zipfile.zip");
unzipper.extractEntry("entry name", "/the/destination/path"); // Fail if a file exists (false argument is implicit)
unzipper.extractEntry("entry name", "/the/destination/path", true); // Replace existing file
unzipper.close();

Return true in case of success or false in case of failure. In case of failure, use unzipper.error(); to get the std::error_code.

• Extracting a single entry from the zip file to memory:

std::vector<unsigned char> unzipped_entry;
Unzipper unzipper("zipfile.zip");
unzipper.extractEntryToMemory("entry name", unzipped_entry);
unzipper.close();

Return true in case of success or false in case of failure. In case of failure, use unzipper.error(); to get the std::error_code.

• Extracting from a vector:

std::vector<unsigned char> zip_vect; // Populated with Zipper zipper(zip_vect);

Unzipper unzipper(zip_vect);
unzipper.extractEntry("Test1");

• Zipper has security against Zip Slip vulnerability: if an entry has a path outside the extraction folder (like ../foo.txt) it will returns false even if the replace option is set.

Hello zip

Basic unzipper standalone application given as demo in doc/demos.

For developers

Non regression tests

Depends on:

• googletest framework
• lcov for code coverage:

Two ways of running them:

• From the root folder:

make check -j`nproc --all`

• From the tests/ folder:

cd tests
make coverage -j`nproc --all`

A coverage report has created an opening. If you do not desire to generate the report.

cd tests
make -j`nproc --all`
./build/Zipper-UnitTest

FAQ

• Q: I used a password when zipping with the Zipper lib, but now when I want to extract data with my operating system zip tool, I got an error. A: By default, Zipper encrypts with the EAS algorithm which is not the default encryption algorithm for zip files. Your operating system zip tools seem not to understand EAS. You can extract it with the 7-Zip tool: 7za e your.zip. If you want the default zip encryption (at your own risk since the password can be cracked) you can remove EAS option in the following files: Make and external/compile-external-libs.sh and recompile the Zipper project.