Implementation:Trailofbits Fickling Is Likely Safe

Knowledge Sources	Fickling
Domains	Security, Validation, Deserialization
Last Updated	2026-02-14 14:00 GMT

Overview

Concrete convenience function for boolean safety assessment of pickle files provided by the Fickling library.

Description

is_likely_safe opens a file, parses it with error tolerance, checks for invalid opcodes, and runs full safety analysis via check_safety. Returns True only if severity is LIKELY_SAFE.

Usage

Use for simple pass/fail safety gates. For detailed results, use check_safety directly.

Code Reference

Source Location

Repository: fickling
File: fickling/analysis.py
Lines: L468-474

Signature

def is_likely_safe(filepath: str) -> bool:
    """Check if a pickle file is likely safe to load.

    Args:
        filepath: Path to the pickle file.

    Returns:
        True only if severity == LIKELY_SAFE after full analysis.
    """

Import

from fickling.analysis import is_likely_safe
# or
from fickling import is_likely_safe

I/O Contract

Inputs

Name	Type	Required	Description
filepath	str	Yes	Path to the pickle file to assess

Outputs

Name	Type	Description
(return)	bool	True only if severity is LIKELY_SAFE; False for any unsafe findings or invalid opcodes

Usage Examples

Quick Safety Gate

from fickling.analysis import is_likely_safe

if is_likely_safe("model.pkl"):
    import pickle
    with open("model.pkl", "rb") as f:
        model = pickle.load(f)
else:
    print("File is not safe to load!")

Post-Injection Verification

from fickling.analysis import is_likely_safe

# Verify that an injected model is correctly detected
assert not is_likely_safe("injected_model.pt"), "Scanner should detect the payload!"

Related Pages

Implements Principle

Principle:Trailofbits_Fickling_Safety_Verification

Uses Heuristic

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