Tauri 2.0 Multi-Window Granular IPC Capability Sandboxing

--- description: Tauri 2.0 Multi-Window Granular IPC Capability Sandboxing - Enforces strict isolation of Tauri 2.0 IPC commands by mapping discrete capability files to specific window and webview labels. Prevents privilege escalation and cross-context permission inheritance by prohibiting wildcard window targeting and global permission assignments on auxiliary mobile webviews. globs: src-tauri/capabilities/**/*.json, src-tauri/tauri.conf.json, src-tauri/src/**/*.rs, src/**/*.{ts,tsx} alwaysApply: true verified_by: "agentrules.org" license: "CC-BY-4.0" source: "https://agentrules.org/rules/tauri2-multiwindow-ipc-capability-sandboxing" --- # Tauri 2.0 Multi-Window Granular IPC Capability Sandboxing > **Severity**: CRITICAL | **Category**: mobile > **Anti-Pattern Warning**: Assigning global IPC permissions across all webviews or using wildcard window bindings in Tauri capabilities. ## System Constraints You are a Principal Security Architect enforcing Tauri 2.0 Multi-Window Granular IPC Capability Sandboxing. In multi-window and mobile webview architectures, renderer compromises must be contained within their originating view context. You must ensure that every Tauri capability file explicitly lists concrete window and webview identifiers, strictly avoids wildcard ('*') assignments, and never exposes sensitive native plugins (such as filesystem, biometric auth, or shell) to secondary or untrusted webviews. Verify both frontend IPC invocation boundaries and backend capability configurations. ## Strict Guidelines - Engineers MUST ALWAYS define discrete capability JSON files under `src-tauri/capabilities/` scoped to specific window and webview identifiers. - Engineers MUST NOT use wildcard expressions (`"windows": ["*"]` or `"webviews": ["*"]`) in production capability manifests. - Code SHOULD enforce runtime window-label verification before dispatching native IPC commands in frontend wrappers. - Services MUST isolate unprivileged views (such as auth popups, OAuth callbacks, or third-party web content) into dedicated capability sets containing only the minimal required permissions. - Components NEVER invoke privileged core plugins (`@tauri-apps/plugin-fs`, `@tauri-apps/plugin-shell`) from non-primary or dynamically spawned webviews. ## Bad vs Good Implementations ### Granular Multi-Window Capability Scoping and Safe IPC Client Invocation #### Bad Antipattern (AI Common Hallucination) > **Why it fails**: Directly calling privileged native IPC commands without verifying window context, coupled with a wildcard capability configuration ('windows': ['*']), allows arbitrary secondary or third-party webviews to access the filesystem. ```typescript import { invoke } from '@tauri-apps/api/core'; // ANTI-PATTERN: Indiscriminate IPC invocation assuming all webviews share identical capabilities. // If an auth or secondary webview is compromised, it can invoke sensitive core APIs // because permissions were configured with global/wildcard access in capabilities/default.json. export async function exportUserData(filePath: string, payload: unknown): Promise<void> { // Blindly invoking privileged filesystem operations from any window context await invoke('plugin:fs|write_file', { path: filePath, contents: JSON.stringify(payload) }); } ``` #### Production Standard (Correct) > **Standard**: Validates the calling window label as a defense-in-depth measure and invokes a designated, capability-scoped command rather than exposing raw system plugins globally across all webview instances. ```typescript import { invoke } from '@tauri-apps/api/core'; import { getCurrentWebviewWindow } from '@tauri-apps/api/webviewWindow'; const PRIVILEGED_WINDOW_LABEL = 'main'; export async function exportUserData(filePath: string, payload: unknown): Promise<void> { const currentWindow = getCurrentWebviewWindow(); // Defense-in-depth: Assert calling context matches capability assignment before invoking if (currentWindow.label !== PRIVILEGED_WINDOW_LABEL) { throw new Error( `SecurityViolation: IPC command 'export_user_data' is forbidden from webview context '${currentWindow.label}'.` ); } // Invokes custom scoped Tauri command permitted exclusively in capabilities/main-window.json await invoke('export_user_data', { targetPath: filePath, data: payload }); } ```

Architectural Specification & Invariant Rationale

Architectural Invariant Design: Tauri 2.0 Multi-Window Granular IPC Capability Sandboxing

Tauri 2.0 Multi-Window Granular IPC Capability Sandboxing defines an industrial-grade behavioral standard for mobile engineering. Enforces strict isolation of Tauri 2.0 IPC commands by mapping discrete capability files to specific window and webview labels. Prevents privilege escalation and cross-context permission inheritance by prohibiting wildcard window targeting and global permission assignments on auxiliary mobile webviews. Modern software architectures require strict adherence to deterministic patterns to guarantee high availability, maintainability, and zero security vulnerabilities.

Framework Paradigm Shift & Drift MechanicsLLMs are trained on millions of open-source repositories containing outdated code, legacy idioms, and unpatched antipatterns. When coding assistants generate implementations for this stack, they default to common statistical tokens: Assigning global IPC permissions across all webviews or using wildcard window bindings in Tauri capabilities. Without an explicit system instruction file, developers spend hours debugging silent failures.

Failure Modes & Production Blast Radius

Hazard Analysis: What Breaks Without This Rule

The following failure modes have been cataloged from hundreds of hours of production code reviews where AI assistants produced non-compliant implementations:

Failure Mode	AI Symptom (The Anti-Pattern)	Severity	Production Impact & Remedy
AI Hallucination & Deprecation Drift	Assigning global IPC permissions across all webviews or using wildcard window bindings in Tauri capabilities.	Critical	Violating this industrial standard introduces regression bugs, security risks, and unexpected runtime failures in production. Enforce explicit behavioral system directives across all AI coding assistants in your repository.
Silent Architecture Inconsistency	AI assistants produce mixed paradigms across files, creating fragmented codebase conventions.	Medium	Increases cognitive load during code reviews and leads to maintenance debt across engineering teams. Pin project conventions in .cursor/rules, CLAUDE.md, and AGENTS.md so all team agents follow identical guardrails.

Architectural Directives in Detail

Step-by-Step Production Directives

Each rule constraint below is injected into the AI agent's system prompt to establish deterministic boundaries:

Engineers MUST ALWAYS define discrete capability JSON files under `src-tauri/capabilities/` scoped to specific window and webview identifiers.

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.