Yara_fn is an IDAPython script that generates YARA rules for reverse engineering and malware analysis workflows within IDA Pro. The script analyzes the current function and creates YARA rules that match basic blocks of code. The tool automatically masks out relocation bytes during rule generation to ensure portability across different memory layouts. It ignores jump instructions to focus on the core functionality of code blocks rather than control flow specifics. When python-yara is installed on the system, the script includes validation functionality that tests the generated rule against segments in the current file. This validation step ensures the rule will match at least one segment, providing immediate feedback on rule effectiveness. The script integrates directly into the IDA Pro environment through the IDAPython interface, allowing analysts to generate detection rules without leaving their reverse engineering workflow. This integration streamlines the process of creating signatures for identified malicious code patterns.