detecting-incorrect-memset

name	detecting-incorrect-memset
description	Detects incorrect use of memset() including wrong argument order, incorrect size calculations, and misunderstood behavior. Use when analyzing memory initialization, buffer clearing, or investigating memset() usage errors.

Incorrect Use of Memset Detection

Detection Workflow

1. Identify memset operations: Find all memset() calls, locate buffer clearing operations, identify memory initialization, map sensitive data handling
2. Analyze argument order: Verify memset argument order, check pointer/value/size order, assess argument correctness, review common mistakes
3. Check size calculation: Verify size parameter, check sizeof usage, assess size correctness, review buffer dimensions
4. Assess security impact: Does incorrect memset leave data? Is sensitive data exposed? Can compiler optimize away memset? What's the security impact?

Key Patterns

• Wrong argument order: memset with wrong argument order, size and value arguments swapped, pointer and size arguments swapped, common memset mistakes
• Incorrect size calculation: sizeof on pointer instead of buffer, off-by-one errors in size, size calculation with overflow, wrong size for buffer type
• Misunderstood memset behavior: expecting memset to return filled value, assuming memset validates arguments, thinking memset checks for NULL, misunderstanding memset return value
• Ineffective clearing: memset on optimized-away variables, compiler removing memset calls, incomplete buffer clearing, missing memset on sensitive data

Output Format

Report with: id, type, subtype, severity, confidence, location, vulnerability, memset_call, correct_order, arguments, actual_operation, expected_operation, exploitable, attack_scenario, impact, mitigation.

Severity Guidelines

• HIGH: Incorrect memset leaving sensitive data
• MEDIUM: Incorrect memset causing memory corruption
• LOW: Minor memset errors

See Also

• patterns.md - Detailed detection patterns and exploitation scenarios
• examples.md - Example analysis cases and code samples
• references.md - CWE references and mitigation strategies