fix: remove unsafe exec() in fw2h.c

[orbisai0security]

Summary

Fix critical severity security issue in tools/fw2h/fw2h.c.

Vulnerability

Field	Value
ID	V-001
Severity	CRITICAL
Scanner	multi_agent_ai
Rule	V-001
File	tools/fw2h/fw2h.c:64

Description: The fw2h build tool uses the unsafe sprintf() function to construct an output filename by appending '.h' to a command-line argument (argv[i]). No bounds check is performed on the length of argv[i] relative to the size of the output_file_name stack buffer. Passing a filename argument longer than the allocated buffer will overflow the stack, potentially overwriting the saved return address and enabling arbitrary code execution.

Changes

• tools/fw2h/fw2h.c

Verification

• Build passes
• Scanner re-scan confirms fix
• LLM code review passed

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Automated security fix by OrbisAI Security