TIKA-4861: reject a BigTIFF directory offset that overflows the prefi…

[tballison]

…x bounds check

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[Copilot]

🟢 Approval recommended

The change is small, localized, and directly addresses the described overflow failure mode with solid regression coverage.

Pull request overview

Fixes an overflow edge case in RawTiffDetector’s prefix bounds checking so malformed BigTIFF directory offsets near Long.MAX_VALUE cannot wrap negative and incorrectly pass the “already in prefix” fast-path (preventing uncaught runtime exceptions during detection).

Changes:

• Harden Prefix.ensure(long end) to reject negative (wrapped) end values before comparing against current buffer length.
• Add targeted regression tests for out-of-range BigTIFF directory offsets and for skipping an invalid “next IFD” follower offset.
• Add a randomized boundary fuzz test for directory-walk offset/count/value arithmetic invariants, and document the fix in CHANGES.txt.

File summaries

File	Description
tika-parsers/tika-parsers-standard/tika-parsers-standard-modules/tika-parser-image-module/src/main/java/org/apache/tika/detect/image/RawTiffDetector.java	Rejects negative/wrapped end in prefix bounds checks to prevent overflow-driven misclassification and exceptions.
tika-parsers/tika-parsers-standard/tika-parsers-standard-modules/tika-parser-image-module/src/test/java/org/apache/tika/detect/image/RawTiffDetectorTest.java	Adds regression coverage for invalid BigTIFF directory offsets and invalid follower offsets.
tika-parsers/tika-parsers-standard/tika-parsers-standard-modules/tika-parser-image-module/src/test/java/org/apache/tika/detect/image/RawTiffDetectorFuzzTest.java	Adds randomized boundary fuzzing to ensure no throwables escape detection across arithmetic edge cases.
CHANGES.txt	Adds release note describing the overflow fix and its impact (TIKA-4861).

Review details

• Files reviewed: 4/4 changed files
• Comments generated: 2
• Review effort level: Lite

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