c-audit-skill

name	c-audit-skill
description	Guidelines and check procedures for identifying vulnerabilities in embedded C/C++ codebase files.

C/C++ Security Audit Guidelines

When analyzing C/C++ source files, pay special attention to the following language-specific vulnerabilities:

1. Memory Safety

• Buffer Overflows & Underflows: Scrutinize array indexing, pointer arithmetic, and loop bounds. Pay special attention to string handling and memory copy operations (e.g., prefer snprintf over sprintf, strncpy over strcpy).
• Pointer Hazards: Look for potential null pointer dereferences, use-after-free conditions, double frees, and dangling pointers.
• Uninitialized Memory: Ensure all variables, particularly pointers and buffers, are properly initialized before use.
• Dynamic Memory Allocation: If dynamic allocation is used (e.g., malloc, free), check for memory leaks and allocation failures. (Note: Embedded firmware often avoids dynamic allocation entirely).

2. Integer Overflows & Underflows

• Type Conversions: Watch out for dangerous implicit conversions, especially between signed and unsigned integers, or narrowing conversions.

3. Error Handling & Return Values

• Exception Safety (if C++): Ensure proper use of RAII (Resource Acquisition Is Initialization) and that exceptions (if enabled) do not leak resources or leave the system in an inconsistent state.

4. Pre-processor Macros

• Macro Safety: Check for pre-processor macros that lack proper parentheses around arguments and the whole expression, or that evaluate arguments multiple times causing side effects.