Summary
BundlePack parses attacker-controlled ZIP records, encrypted container headers and chunks, JSON manifests, PNG metadata, and GIF block structures, but the repository has no fuzz target, property-based framework, minimized crash corpus, or systematic boundary matrix.
Current malformed fixtures cover only a small set of hand-written cases.
Impact
Crashes, hangs, oversized allocations, parser differentials, and off-by-one limit errors can survive the current smoke tests even when normal and selected hostile cases pass.
Evidence
macOS/Scripts/test.sh:18-61Windows/BundlePack.Core.Tests/BundlePack.Core.Tests.csproj:1-9macOS/Tests/EndToEndSmoke.ArchiveValidation.swift:38-160Windows/BundlePack.Core.Tests/ArchiveValidationScenarios.cs:20-106macOS/BundlePack/Shared/ZipArchiveInspector.Validation.swiftmacOS/BundlePack/Shared/EncryptedContainer.Header.swiftmacOS/BundlePack/Shared/PackageManifest.swift:15-29
Proposed change
Create fuzz and generated-fixture targets for:
- ZIP EOCD, central and local records
- encrypted fixed header and chunk layout
- manifest JSON
- PNG structural validation
- GIF blocks and sub-blocks
Add deterministic boundary cases for:
- entries: 9,998 / 9,999 / 10,000
- metadata: 16 MiB - 1 / exact / + 1
- expanded size: 20 GiB - 1 / exact / + 1
- ratio threshold around 1 GiB and 1,000 / 1,001
- KDF iterations and chunk-size accepted ranges
- data descriptors, ZIP64 sentinels, invalid UTF-8, overlapping ranges, duplicate offsets, and file-directory prefix conflicts
- PNG/GIF dimension, frame, CRC, truncation, and trailing-data boundaries
Acceptance criteria
- PR CI runs each seed corpus for a short bounded duration.
- A nightly workflow runs sanitizer-enabled fuzzing for 15 to 30 minutes per target.
- The oracle rejects crashes, traps, hangs, unclassified exceptions, and allocations beyond configured budgets.
- Accepted archives always satisfy path containment, manifest-to-payload agreement, and configured limits.
- Failures store the seed, iteration, and minimized input as CI artifacts.
- Large-limit tests use synthetic records or sparse streams rather than checked-in multi-GiB binaries.
Compatibility constraints
Do not make the fuzzer define the format. Expected accept/reject behavior must come from Docs/FORMAT.md and the neutral conformance corpus.
Summary
BundlePack parses attacker-controlled ZIP records, encrypted container headers and chunks, JSON manifests, PNG metadata, and GIF block structures, but the repository has no fuzz target, property-based framework, minimized crash corpus, or systematic boundary matrix.
Current malformed fixtures cover only a small set of hand-written cases.
Impact
Crashes, hangs, oversized allocations, parser differentials, and off-by-one limit errors can survive the current smoke tests even when normal and selected hostile cases pass.
Evidence
macOS/Scripts/test.sh:18-61Windows/BundlePack.Core.Tests/BundlePack.Core.Tests.csproj:1-9macOS/Tests/EndToEndSmoke.ArchiveValidation.swift:38-160Windows/BundlePack.Core.Tests/ArchiveValidationScenarios.cs:20-106macOS/BundlePack/Shared/ZipArchiveInspector.Validation.swiftmacOS/BundlePack/Shared/EncryptedContainer.Header.swiftmacOS/BundlePack/Shared/PackageManifest.swift:15-29Proposed change
Create fuzz and generated-fixture targets for:
Add deterministic boundary cases for:
Acceptance criteria
Compatibility constraints
Do not make the fuzzer define the format. Expected accept/reject behavior must come from
Docs/FORMAT.mdand the neutral conformance corpus.