Merge pull request #40 from mdimado/final-report-gsoc-mdimado

Final report gsoc mdimado

Author: fish98

contributions/GSoC 2025 - Integrating OSS-Fuzz for Go-Based and Python-Based OpenPrinting Projects/Final report.md

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+# Integrating Go- and Python-based OpenPrinting Projects in OSS-Fuzz
+
+
+* **Year**: 2025
+* **Contributor**: Mohammed Imaduddin
+* **Organization**: OpenPrinting, The Linux Foundation
+* **Mentors**: Till Kamppeter, Jiongchi Yu, George Andrei Iosif
+* **Useful Links**:
+
+  * [Project Page](https://summerofcode.withgoogle.com/programs/2025/projects/rBWHXaha)
+  * [Source Code for Fuzz Harnesses](https://github.com/OpenPrinting/fuzzing)
+  * [OSS-Fuzz](https://github.com/google/oss-fuzz) Projects
+
+    * [goipp](https://github.com/google/oss-fuzz/tree/master/projects/goipp)
+    * [ipp-usb](https://github.com/google/oss-fuzz/tree/master/projects/ipp-usb)
+    * [pyppd](https://github.com/google/oss-fuzz/tree/master/projects/pyppd)
+    * [pycups](https://github.com/google/oss-fuzz/tree/master/projects/pycups)
+  * [IPP-over-USB Emulator](https://github.com/OpenPrinting/go-mfp/tree/master/proto/usbip)
+
+
+---
+
+## Project Context and Significance
+
+OpenPrinting develops and maintains printing-related software, standards, and resources for Linux and other Unix-like systems. It maintains the printer/driver database and key components such as cups-filters and “Printer Applications” which enable IPP-based and driverless printing when used together with CUPS. While previous GSoC work successfully integrated C/C++-based OpenPrinting projects into OSS-Fuzz (achieving 21 bug fixes from 41 discovered issues), **no Go or Python projects had ever been integrated into OSS-Fuzz before this project**.
+
+This project addresses a significant gap in security testing for key printing infrastructure components:
+
+* **goipp** – A Go library maintained by OpenPrinting that implements the Internet Printing Protocol (IPP) for encoding and decoding IPP messages in Go.
+
+* **ipp-usb** – An OpenPrinting userspace daemon that exposes USB printers as local IPP network printers (IPP-over-USB proxy), enabling driverless printing for modern USB devices.
+
+* **pyppd** – A Python library/utility from OpenPrinting for reading, compressing, and decompressing PostScript Printer Description (PPD) files.
+
+* **pycups** – Python bindings to the CUPS API (libcups), allowing Python applications to manage printers and print jobs through CUPS.
+
+The challenge was particularly complex because these projects involve language bindings, hardware-dependent code, and network protocols that are difficult to test without specialized infrastructure.
+
+---
+
+## Previous Work
+
+Building on the foundation established during GSoC 2024, the C/C++ integration work by Jiongchi Yu had already:
+- Integrated CUPS and libcups into OSS-Fuzz, discovering 41 security issues with 21 fixes
+- Established the [OpenPrinting/fuzzing](https://github.com/OpenPrinting/fuzzing) repository structure
+- Created workflows for maintaining fuzzing harnesses externally while integrating with OSS-Fuzz
+- Demonstrated the value of continuous fuzzing for critical printing infrastructure
+
+---
+
+## Work Completed During This Project
+
+This project represents the **first successful integration of Go and Python projects into OSS-Fuzz**.
+
+### Technical Achievements by Project
+
+**goipp - Go IPP Implementation**
+
+* Created **5 comprehensive fuzz harnesses** targeting core IPP message processing:
+
+  * `fuzz_decode_bytes.go`: Tests IPP message deserialization with malformed input
+  * `fuzz_decode_bytes_ex.go`: Extended deserialization testing with additional parameters
+  * `fuzz_collections.go`: Tests complex IPP Collection attribute handling
+  * `fuzz_round_trip.go`: Validates encode/decode consistency to catch data corruption
+  * `fuzz_tag_extension.go`: Tests custom IPP tag extensions parsing
+* **Pull Requests Created**:
+
+  * [OpenPrinting/fuzzing PR #10](https://github.com/OpenPrinting/fuzzing/pull/10)
+  * [OpenPrinting/fuzzing PR #11](https://github.com/OpenPrinting/fuzzing/pull/11)
+  * [OpenPrinting/fuzzing PR #12](https://github.com/OpenPrinting/fuzzing/pull/12)
+  * [OpenPrinting/fuzzing PR #13](https://github.com/OpenPrinting/fuzzing/pull/13)
+  * [OpenPrinting/fuzzing PR #18](https://github.com/OpenPrinting/fuzzing/pull/18)
+  * [OSS-Fuzz PRs for goipp](https://github.com/google/oss-fuzz/tree/master/projects/goipp)
+
+**ipp-usb - IPP-over-USB Daemon**
+
+* Developed **3 specialized fuzzers** for hardware-dependent code:
+
+  * `daemon_fuzzer.go`: Tests the main daemon with malformed HTTP/IPP requests
+  * `usb_fuzzer.go`: Tests USB protocol parsing using mock USB/IP infrastructure
+  * `http_client_fuzzer.go`: Tests HTTP client resilience against malicious server responses
+* **Major Innovation**: Built a virtual IPP-over-USB emulator using USB/IP protocol, enabling fuzzing of hardware-dependent code paths without requiring physical USB printers
+* **Pull Requests Created**:
+
+  * [OpenPrinting/fuzzing PR #26](https://github.com/OpenPrinting/fuzzing/pull/26)
+  * [OSS-Fuzz PRs for ipp-usb](https://github.com/google/oss-fuzz/tree/master/projects/ipp-usb)
+
+**pyppd - Python PPD Archive Manager**
+
+* Implemented **7 Python fuzz harnesses** covering file processing and compression:
+
+  * `fuzz_archive.py`: Tests PPD file archiving with malformed input
+  * `fuzz_compress.py`: Tests compression/decompression of PPD files
+  * `fuzz_compressor.py`: Tests round-trip compression consistency
+  * `fuzz_find_files.py`: Tests file discovery with malicious patterns
+  * `fuzz_ppd.py`: Tests PPD file parsing with corrupted data
+  * `fuzz_read_file_in_syspath.py`: Tests system path file access
+  * `fuzz_runner.py`: Tests command-line argument parsing
+* **Pull Requests Created**:
+
+  * [OpenPrinting/fuzzing PR #31](https://github.com/OpenPrinting/fuzzing/pull/31)
+  * [OpenPrinting/fuzzing PR #32](https://github.com/OpenPrinting/fuzzing/pull/32)
+  * [OpenPrinting/fuzzing PR #36](https://github.com/OpenPrinting/fuzzing/pull/36)
+  * [OpenPrinting/fuzzing PR #37](https://github.com/OpenPrinting/fuzzing/pull/37)
+  * [OSS-Fuzz PRs for pyppd](https://github.com/google/oss-fuzz/tree/master/projects/pyppd)
+
+**pycups - Python CUPS Bindings**
+
+* Created **7 fuzz harnesses** for critical CUPS operations:
+
+  * `fuzz_auth_callback.py`: Tests authentication callback handling
+  * `fuzz_buffer_handling.py`: Tests buffer management and memory safety
+  * `fuzz_file_handling.py`: Tests file I/O operations
+  * `fuzz_ipp_io.py`: Tests IPP request/response processing
+  * `fuzz_print_job.py`: Tests job submission with malformed parameters
+  * `fuzz_printer_management.py`: Tests printer configuration operations
+  * `fuzz_UTF8.py`: Tests string encoding/decoding across all functions
+* **Pull Requests Created**:
+
+  * [OpenPrinting/fuzzing PR #27](https://github.com/OpenPrinting/fuzzing/pull/27)
+  * [OpenPrinting/fuzzing PR #28](https://github.com/OpenPrinting/fuzzing/pull/28)
+  * [OpenPrinting/fuzzing PR #29](https://github.com/OpenPrinting/fuzzing/pull/29)
+  * [OpenPrinting/fuzzing PR #35](https://github.com/OpenPrinting/fuzzing/pull/35)
+  * [OSS-Fuzz PRs for pycups](https://github.com/google/oss-fuzz/tree/master/projects/pycups)
+
+---
+
+## Impact and Technical Challenges Overcome
+
+### Why This Work Was Difficult
+
+1. Integrated four very different OpenPrinting projects (Go libraries, Python bindings, and utilities) into OSS-Fuzz, each with its own language, build system and fuzzing engine.
+2. Dealt with hardware-dependent paths in ipp-usb and pycups by creating a virtual IPP-over-USB printer/emulator to fuzz code that normally requires real devices.
+3. Designed seed corpora and mutation strategies tailored to both IPP messages and legacy PPD files to exercise diverse input formats.
+4. Maintained all fuzzers externally and wired them into OSS-Fuzz with custom Dockerfiles and build scripts to keep upstream trees clean.
+
+### Quantified Impact
+
+- **Code Coverage Achieved**: [To be measured after September PRs get merged ;(]
+- **Projects Newly Covered**: 4 major OpenPrinting projects
+
+### Recommendations for Future Contributors
+
+1. Reuse and extend the existing fuzz harnesses and seed corpora instead of starting from scratch.
+2. Continue improving code coverage in hardware-dependent areas of ipp-usb by enhancing the virtual device emulator.
+3. Keep fuzzers in an external module and use clear build scripts/Dockerfiles to simplify OSS-Fuzz integration.
+4. Triage and upstream any OSS-Fuzz findings promptly to maintainers.
+5. Add unit tests alongside fuzzers to ensure deterministic coverage of critical functions.
+
+---
+
+## Future Development
+
+1. Extend fuzzing coverage across all four projects by adding new harnesses and expanding the seed corpora to cover edge cases and rarely used code paths.
+2. Enhance the virtual IPP-over-USB emulator to simulate more device behaviors (if possible) for deeper fuzzing of hardware-dependent code.
+3. Integrate continuous fuzzing feedback by monitoring OSS-Fuzz reports and filing/triaging issues promptly with maintainers.
+4. Broaden test coverage in projects like pycups and pyppd by adding unit tests to complement fuzzing.
+5. Document the fuzzing setup so future contributors can easily reproduce, extend, and maintain it.
+
+---
+
+## Acknowledgment
+
+I would like to thank my mentors for their guidance and support throughout this project. **Till Kamppeter** provided invaluable domain expertise on printing protocols and the OpenPrinting architecture. **George-Andrei Iosif** shared his deep knowledge of fuzzing methodologies and the **OSS-Fuzz** infrastructure. **Jiongchi Yu** deserves special recognition for his mentorship, building on his previous GSoC work and offering detailed technical guidance at every step, especially in fuzzing and OSS-Fuzz integration. I am also grateful to **Alexander Pevzner**, the author of **goipp** and **ipp-usb**, for helping me create fuzzing harnesses for these projects and for assisting in the development of the IPP-over-USB emulator using USB/IP. I would also like to thank **Google’s OSS-Fuzz maintainers** for promptly reviewing and merging pull requests. Finally, I thank the wider **OpenPrinting community** and the **Linux Foundation** for maintaining the projects and infrastructure that made this work possible.