Add Fuzz Tests#26384
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TravisEz13 merged 6 commits intoPowerShell:masterfrom Nov 6, 2025
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Pull Request Overview
This PR adds fuzzing infrastructure for PowerShell using SharpFuzz and libfuzzer-dotnet. The fuzzing targets the HyperV socket token extraction functionality in the remoting layer to discover potential parsing vulnerabilities.
Key changes:
- Adds fuzzing test infrastructure with a dedicated FuzzingApp project
- Refactors token extraction logic into a testable
ExtractFuzzedTokenmethod - Exposes internal methods for fuzzing via
InternalsVisibleToattribute
Reviewed Changes
Copilot reviewed 7 out of 7 changed files in this pull request and generated 7 comments.
Show a summary per file
| File | Description |
|---|---|
| test/fuzzing/runFuzzer.ps1 | New PowerShell script to orchestrate the fuzzing workflow (build, instrument, execute) |
| test/fuzzing/FuzzingApp/powershell-fuzz-tests.csproj | Project file for fuzzing test harness targeting .NET 10.0 |
| test/fuzzing/FuzzingApp/Program.cs | Fuzzing harness entry point that invokes SharpFuzz on token extraction |
| test/fuzzing/inputs/mininput | Minimal fuzzing corpus input |
| test/fuzzing/inputs/maxinput | Maximum fuzzing corpus input with extended character set |
| src/System.Management.Automation/engine/remoting/common/RemoteSessionHyperVSocket.cs | Refactors token parsing into ExtractFuzzedToken method and updates call sites |
| src/System.Management.Automation/AssemblyInfo.cs | Adds InternalsVisibleTo for fuzzing test assembly |
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Co-authored-by: anamnavi <annavied@microsoft.com>
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Co-authored-by: anamnavi <annavied@microsoft.com>
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PR Summary
PR Context
Add fuzz tests, to fuzz token received from HyperV-Socket response. This uses LibFuzzer and SharpFuzz, and the tests can be run via the included script, which builds the FuzzingApp project, instruments its .dll as well as the dependent SMA .dll. The corpus includes 2 files, maxinput and mininput as valid input examples.
PR Checklist
.h,.cpp,.cs,.ps1and.psm1files have the correct copyright header