fix(scan): cap per-file allocation via MaxFileSize to prevent memory DoS#2924
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BiswajeetRay7 wants to merge 1 commit into
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fix(scan): cap per-file allocation via MaxFileSize to prevent memory DoS#2924BiswajeetRay7 wants to merge 1 commit into
BiswajeetRay7 wants to merge 1 commit into
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Both filesystem scan (scan.go) and container image scan (osvscanner.go) constructed scalibr.ScanConfig without MaxFileSize. scalibr documents 0 as 'no limit', so 20+ lockfile/manifest extractors that io.ReadAll on input.Reader could allocate arbitrarily large memory for attacker-supplied files (repo files up to 2 GB via git-LFS, or unbounded container-image layer entries). Add defaultMaxFileSize = 512 MiB matching the image-layer scanner's MaxFileBytes and pass it to both ScanConfig sites. This aligns with the JAR extractor's existing defaultMaxZipBytes pattern. Refs: docs/migrating-from-scalibr.md:104 lists --max-file-size as 'Not yet available'. This change wires the default so the safeguard exists regardless of the CLI flag.
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Problem
Both filesystem scan (
pkg/osvscanner/scan.go:240) and container image scan (pkg/osvscanner/osvscanner.go:321) constructscalibr.ScanConfigwithoutMaxFileSize. scalibr documents0as "no limit" (osv-scalibr/extractor/filesystem/filesystem.go:114), so 20+ lockfile/manifest extractors that callio.ReadAll(input.Reader)can allocate arbitrarily large memory for attacker-supplied files.Realistic attack sources:
actions/checkoutlfs: true)On GitHub-hosted runners (7 GB RAM), a single ~2 GB
package-lock.jsonorCargo.lockcan OOM-kill the scanner during JSON parse (JSON parsing typically allocates 3-5× file size).Fix
defaultMaxFileSize = 512 * 1024 * 1024(512 MiB) as a package-level constant, matchingosv-scalibr's image-layer scannerMaxFileBytesdefault.scalibr.ScanConfigsites.Aligns with the JAR extractor's existing
defaultMaxZipBytespattern (osv-scalibr/extractor/filesystem/language/java/archive/archive.go:52) — extending the same safe-default philosophy to file-level ingestion.Related
docs/migrating-from-scalibr.md:104currently lists--max-file-sizeas "Not yet available". This change wires the default so the safeguard exists regardless of whether the CLI flag lands.Testing
Existing test suite exercises files well under 512 MiB — no behavior change for real-world scans. Manual verify: repo with
Cargo.lock>512 MiB is now skipped (as documented byfilesystem.go:519-529whenmaxFileSize > 0).