Fighting Game · Guides & deep dives

Mod Sandboxing

The default sandbox denies filesystem access outside the mod root, denies network access, denies native code, caps script memory at 256 MiB, caps mod-scoped storage at 104,857,600 bytes, and caps script timeouts at 100 ms.

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This document covers TODOS.phase-72.72.14.1.3: sandbox policy enforcement for .mayamod execution.

Runtime Surface#

  • module: V2Modding
  • policy: FV2ModSandboxPolicy
  • request: FV2ModSandboxRequest
  • decision: FV2ModSandboxDecision
  • helper functions: BuildDefaultModSandboxPolicy, IsPathInsideModRoot, and EvaluateModSandboxRequest
  • automation: V2/ue/Source/V2Tests/Private/Modding/ModLoadingSystem.spec.cpp
  • contract: V2/ue/Content/V2/Modding/ModSandboxing_V2_Contract.json

Policy#

The default sandbox denies filesystem access outside the mod root, denies network access, denies native code, caps script memory at 256 MiB, caps mod-scoped storage at 104,857,600 bytes, and caps script timeouts at 100 ms.

IsPathInsideModRoot canonicalizes paths, collapses relative segments, rejects .., and only allows a requested path when it equals the mod root or sits below the mod root. EvaluateModSandboxRequest returns explicit issue types for filesystem escape, network denial, native-code denial, memory overflow, storage overflow, and timeout overflow.

Later scripting and asset-loading tasks consume this policy instead of opening new filesystem, network, or resource-limit paths directly.

Verification#

bash
python3 V2/ue/Tools/check-v2-mod-sandboxing.py
python3 V2/ue/Tools/check-v2-mod-loading-system.py
python3 V2/ue/Tools/check-v2-ci-workflow.py
python3 V2/tools/validate-v2-docs.py
python3 -m py_compile V2/ue/Tools/check-v2-mod-sandboxing.py V2/ue/Tools/check-v2-mod-loading-system.py V2/ue/Tools/check-v2-ci-workflow.py
python3 -m json.tool V2/ue/Content/V2/Modding/ModSandboxing_V2_Contract.json