Fix val_mem_copy overflow bounds checking

[jk-arm]

Summary

• add destination-size awareness to val_mem_copy to prevent overruns
• clamp requested length and ignore null inputs
• update the only call site to provide the buffer size

Testing

• Not run (not requested)

[Copilot]

Pull request overview

This PR enhances the val_mem_copy function to prevent buffer overflows by adding destination buffer size awareness. The function signature is updated to include a dest_size parameter, and the implementation now validates inputs and clamps the copy length to prevent writing beyond the destination buffer boundaries.

Key changes:

• Added dest_size parameter to val_mem_copy for bounds checking
• Implemented input validation (null checks) and length clamping logic
• Updated the single call site in val_common_log.c to pass the destination buffer size

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
inc/val_common_framework.h	Updated function declaration to include dest_size parameter
src/val_common_framework.c	Added input validation, bounds checking, and length clamping to prevent buffer overflows
src/val_common_log.c	Updated call site to provide destination buffer size

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[Copilot]

The clamping logic should be len < dest_size ? len : dest_size - 1 to reserve space for null termination if dest is used as a string buffer. Without this, copying exactly dest_size bytes leaves no room for a null terminator, potentially causing issues in string operations. Alternatively, if this function is not meant for string copying, consider documenting that null termination is the caller's responsibility.

[Copilot]

After calling val_mem_copy with length len - 1, the code writes to indices len - 1, len, and len + 1 without verifying these indices are within formatted_msg bounds. If the clamping in val_mem_copy reduces bytes_to_copy due to buffer size constraints, these subsequent writes could still overflow the buffer. Consider checking the return value or ensuring len + 1 < sizeof(formatted_msg) before these writes.