Add DoS protection against expansion attacks (Billion Laughs style) #211
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Implement defense in depth against exponential expansion attacks that could cause Fickling to hang or consume excessive memory: 1. Static pattern detection via ExpansionAttackAnalysis: - Detects high GET/PUT ratio (>10x suspicious, >50x likely unsafe) - Detects excessive DUP operations (>100 suspicious) 2. Runtime resource limits via InterpreterLimits: - max_opcodes: 1,000,000 - max_stack_depth: 10,000 - max_memo_size: 100,000 - max_get_ratio: 50 (GETs per PUT) 3. New exception types: - ResourceExhaustionError for limit violations - ExpansionAttackError for expansion attack detection 4. Updated opcode classes to track GET/PUT operations: - BinGet, LongBinGet, Get call track_get() - BinPut, Put, LongBinPut, Memoize call track_put() 5. AnalysisContext catches ResourceExhaustionError and returns LIKELY_OVERTLY_MALICIOUS severity instead of propagating exception Fixes #111 Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
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Summary
ExpansionAttackAnalysisto flag suspicious opcode patternsInterpreterLimitsto stop runaway executionTest plan
pytest test/test_crashes.py::TestExpansionAttacks -v- all 6 new tests passcurl -O https://raw.githubusercontent.com/coldwaterq/pickle_injector/main/globalLaughs.pt fickling globalLaughs.pt # Should flag as suspicious/unsafe🤖 Generated with Claude Code