Summary GWP-ASan Sampling-Based Detection of Memory-Safety Bugs arxiv.org
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GWP-ASan is a tool that finds memory-safety bugs in C and C++ apps and provides error messages to help fix them, with a focus on effectiveness and continuous improvement.
Slides
Slide Presentation (8 slides)
Key Points
- GWP-ASan is a family of tools developed by Google to detect memory-safety bugs in production with minimal overhead.
- It combines page-granular guarded allocation with low-rate sampling to detect bugs in C and C++ applications.
- GWP-ASan is integrated into malloc() implementations and does not require modifications to program binaries.
- It complements pre-production bug detection tools by detecting bugs that may have been missed during testing.
- GWP-ASan provides detailed error messages that help developers fix bugs without requiring reproducers.
- There are multiple implementations of GWP-ASan, each tailored to different platforms and use cases.
- Real-world deployment of GWP-ASan has successfully detected and fixed thousands of memory-safety bugs.
- Future work includes extending GWP-ASan to detect additional bug classes and improving its bug detection capabilities.
Summaries
22 word summary
GWP-ASan detects memory-safety bugs in C and C++ applications, providing error messages for bug fixing. It is effective and aims for improvement.
54 word summary
GWP-ASan is a Google-developed tool that detects memory-safety bugs in C and C++ applications without modifying program binaries. It integrates into malloc() implementations and provides detailed error messages for bug fixing. Real-world deployment has successfully detected and fixed thousands of bugs. Future work includes extending capabilities and optimizing implementations to improve overall product security.
143 word summary
GWP-ASan is a family of tools developed by Google to detect memory-safety bugs in C and C++ applications with minimal overhead. It integrates into malloc() implementations and does not require modifications to program binaries. GWP-ASan complements other bug detection tools and provides detailed error messages for bug fixing without reproducers. The algorithm design of GWP-ASan includes functions like malloc(), free(), WantToSample(), GuardAlloc(), and GuardDealloc(). Various implementations exist for different platforms and use cases. Real-world deployment has successfully detected and fixed thousands of memory-safety bugs. Bug reports are processed through existing telemetry and bug reporting systems. Future work includes extending capabilities, optimizing implementations, exploring higher sampling rates, combining with other mechanisms, dynamically directing the sampling budget, and improving memory tagging hardware features. GWP-ASan is an effective tool for detecting memory-safety bugs with minimal overhead, complementing pre-production bug detection mechanisms and improving overall product security.
358 word summary
GWP-ASan is a family of tools developed by Google to detect memory-safety bugs in C and C++ applications with minimal overhead. It combines guarded allocation with low-rate sampling and has been successful in detecting bugs in mobile, desktop, and server applications. GWP-ASan is integrated into malloc() implementations and does not require modifications to program binaries.
GWP-ASan is meant to complement other pre-production bug detection tools like ASan or HWASan. It provides detailed error messages that enable developers to fix bugs without requiring reproducers. The name "GWP-ASan" is derived from Google-Wide Profiling (GWP) and AddressSanitizer (ASan), although it is not the same as either of them. There are multiple implementations of GWP-ASan, each with its own name.
Heap memory-safety bugs, such as heap buffer overflows and use-after-free accesses, are considered undefined behavior in C and C++. Dynamic analysis tools like Valgrind Memcheck and ASan have been developed to detect these bugs during pre-production testing. However, maintaining additional information for debugging can be costly.
The algorithm design of GWP-ASan is described in detail. It includes functions like malloc(), free(), WantToSample(), GuardAlloc(), and GuardDealloc(). The algorithm uses guarded allocation and sampling to detect memory-safety bugs in a low-overhead manner. Various implementations of GWP-ASan exist for different platforms and use cases, including TCMalloc, Google Chrome, Android/LLVM, Firefox, Apple Platforms, and the Linux Kernel.
Real-world deployment of GWP-ASan has successfully detected and fixed thousands of memory-safety bugs across different applications and platforms. The bug detection frequency varies, with some bugs occurring frequently and others occurring only once. Bug reports are processed through existing telemetry and bug reporting systems, and the additional information provided by GWP-ASan reports has been valuable for debugging and fixing issues.
Future work on GWP-ASan includes extending its capabilities to detect additional bug classes, optimizing existing implementations, exploring higher sampling rates, combining with other detection mechanisms, dynamically directing the sampling budget, and improving memory tagging hardware features.
In conclusion, GWP-ASan is an effective tool for detecting memory-safety bugs in production with minimal overhead. It complements pre-production bug detection mechanisms and improves overall product security by enabling developers to fix vulnerabilities. Further improvements and optimizations can enhance its bug detection capabilities.
551 word summary
GWP-ASan is a family of tools developed by Google that detect memory-safety bugs in production with near-zero overhead. These bugs, such as heap-use-after-free and heap-buffer-overflow, continue to be a major problem in applications written in C or C++. While memory-safe languages offer a solution, the existing code bases in C and C++ are extensive and require additional bug detection mechanisms.
The basic algorithm behind GWP-ASan combines page-granular guarded allocation with low-rate sampling. This approach adds an "if" statement to the Electric Fence algorithm and has been successful in detecting bugs in production across mobile, desktop, and server applications. GWP-ASan is integrated into malloc() implementations and does not require modifications to program binaries.
GWP-ASan does not replace other pre-production bug detection tools like ASan or HWASan but complements them by detecting bugs that may have been missed during pre-production testing. The low probability of detecting bugs per instance is offset by large-scale production deployment, resulting in a significant number of bug detections. GWP-ASan provides detailed error messages that enable developers to fix bugs without requiring reproducers.
The name "GWP-ASan" is derived from Google-Wide Profiling (GWP) and AddressSanitizer (ASan), although GWP-ASan is neither GWP nor ASan. There are multiple implementations of GWP-ASan, each with its own name.
The background section explains heap memory-safety bugs, such as heap buffer overflows and use-after-free accesses, which are considered undefined behavior in C and C++. Dynamic analysis tools, like Valgrind Memcheck and ASan, have been developed to detect these bugs during pre-production testing. However, dynamic analysis can only observe program transitions into erroneous states and maintaining additional information for debugging can be costly.
GWP-ASan's algorithm design is described in detail. The basic implementation includes functions like malloc(), free(), WantToSample(), GuardAlloc(), and GuardDealloc(). The algorithm uses guarded allocation and sampling to detect memory-safety bugs in a low-overhead manner. The simple version of the algorithm initializes a fixed-size pool of virtual memory with guarded allocation slots and guard pages. Sampling is performed based on a thread-local skip counter, and guard pages are made accessible for allocated slots. Deallocation of sampled allocations marks the corresponding slot as inaccessible. Error messages are generated when memory accesses hit protected pages, providing stack traces and other relevant information.
Various implementations of GWP-ASan are listed, including TCMalloc, Google Chrome, Android/LLVM, Firefox, Apple Platforms, and the Linux Kernel. Each implementation has its own features and optimizations tailored to different platforms and use cases.
The results of real-world deployment show that GWP-ASan has been successful in detecting and fixing memory-safety bugs. Thousands of bugs have been reported and fixed across different applications and platforms. The detection frequency of bugs varies, with some bugs occurring frequently and others occurring only once. The bug reports are processed through existing telemetry and bug reporting systems, and the additional information provided by GWP-ASan reports has been valuable for debugging and fixing issues.
Future work includes extending GWP-ASan to detect additional bug classes, tuning existing implementations, exploring higher sampling rates, combining with other detection mechanisms, dynamically directing the sampling budget, and improving memory tagging hardware features.
In conclusion, GWP-ASan is an effective tool for detecting memory-safety bugs in production with minimal overhead. It complements pre-production bug detection mechanisms and improves overall product security by enabling developers to fix vulnerabilities. Further improvements and optimizations can be made to enhance bug detection capabilities.