Configuring Tauri Permissions

Tauri Permissions Configuration

This skill covers the Tauri v2 permission system for controlling frontend access to backend commands and system resources.

Permission System Overview

Permissions in Tauri are explicit privileges that grant or deny access to specific commands. They form the security boundary between frontend code and system resources.

Core Components

Security Model

• Frontend code cannot access commands without explicit permission
• Deny rules always take precedence over allow rules
• Permissions must be linked to capabilities to be active
• Each window/webview can have different permissions

Permission Identifiers

Naming Convention

Format: <plugin-name>:<permission-type>

Identifier Rules

• Lowercase ASCII letters only: [a-z]
• Maximum length: 116 characters
• Plugin prefixes (tauri-plugin-) added automatically at compile time

Directory Structure

Application Structure

src-tauri/
├── capabilities/
│   ├── default.json          # Main capability file
│   └── admin.toml            # Additional capabilities
├── permissions/
│   └── custom-permission.toml # Custom app permissions
└── tauri.conf.json

Plugin Structure

tauri-plugin-example/
├── permissions/
│   ├── default.toml          # Default permission set
│   ├── autogenerated/        # Auto-generated from commands
│   │   └── commands/
│   └── custom-scope.toml     # Custom scopes
└── src/
    ├── commands.rs
    └── build.rs

Capability Configuration

Capabilities link permissions to windows and define what frontend contexts can access.

JSON Format (Recommended for Apps)

{
  "$schema": "../gen/schemas/desktop-schema.json",
  "identifier": "main-capability",
  "description": "Main window permissions",
  "windows": ["main"],
  "permissions": [
    "core:default",
    "fs:default",
    "fs:allow-read-text-file",
    {
      "identifier": "fs:allow-write-text-file",
      "allow": [{ "path": "$APPDATA/*" }]
    }
  ]
}

TOML Format

"$schema" = "../gen/schemas/desktop-schema.json"
identifier = "main-capability"
description = "Main window permissions"
windows = ["main"]
permissions = [
  "core:default",
  "fs:default",
  "fs:allow-read-text-file"
]

[[permissions]]
identifier = "fs:allow-write-text-file"
allow = [{ path = "$APPDATA/*" }]

Window Targeting

{
  "identifier": "admin-capability",
  "windows": ["admin", "settings"],
  "permissions": ["fs:allow-write-all"]
}

Use "*" to target all windows:

{
  "windows": ["*"],
  "permissions": ["core:default"]
}

Platform-Specific Capabilities

{
  "identifier": "desktop-capability",
  "platforms": ["linux", "macOS", "windows"],
  "windows": ["main"],
  "permissions": ["fs:allow-app-read-recursive"]
}

{
  "identifier": "mobile-capability",
  "platforms": ["iOS", "android"],
  "windows": ["main"],
  "permissions": ["fs:allow-app-read"]
}

Allow and Deny Lists

Basic Scope Configuration

{
  "identifier": "fs:allow-read-file",
  "allow": [
    { "path": "$HOME/Documents/*" },
    { "path": "$APPDATA/**" }
  ],
  "deny": [
    { "path": "$HOME/Documents/secrets/*" }
  ]
}

Scope Variables

Glob Patterns

Deny Precedence

Deny rules always override allow rules:

{
  "permissions": [
    {
      "identifier": "fs:allow-read-file",
      "allow": [{ "path": "$HOME/**" }],
      "deny": [{ "path": "$HOME/.ssh/**" }]
    }
  ]
}

Plugin Permissions

Using Default Plugin Permissions

{
  "permissions": [
    "fs:default",
    "shell:default",
    "http:default",
    "dialog:default"
  ]
}

Common Plugin Permission Patterns

Filesystem Plugin

{
  "permissions": [
    "fs:default",
    "fs:allow-read-text-file",
    "fs:allow-write-text-file",
    "fs:allow-app-read-recursive",
    "fs:allow-app-write-recursive",
    "fs:deny-default"
  ]
}

HTTP Plugin

{
  "permissions": [
    "http:default",
    {
      "identifier": "http:default",
      "allow": [{ "url": "https://api.example.com/*" }],
      "deny": [{ "url": "https://api.example.com/admin/*" }]
    }
  ]
}

Shell Plugin

{
  "permissions": [
    "shell:allow-open",
    {
      "identifier": "shell:allow-execute",
      "allow": [
        { "name": "git", "cmd": "git", "args": true }
      ]
    }
  ]
}

Directory-Specific Filesystem Permissions

Custom Permission Definition

TOML Permission File

Create src-tauri/permissions/my-permission.toml:

[[permission]]
identifier = "my-app:config-access"
description = "Access to app configuration files"
commands.allow = ["read_config", "write_config"]

[[scope.allow]]
path = "$APPCONFIG/*"

[[scope.deny]]
path = "$APPCONFIG/secrets.json"

Permission Sets

Group multiple permissions:

[[set]]
identifier = "my-app:full-access"
description = "Full application access"
permissions = [
  "my-app:config-access",
  "fs:allow-app-read-recursive",
  "fs:allow-app-write-recursive"
]

Auto-Generated Command Permissions

In plugin src/build.rs:

const COMMANDS: &[&str] = &["get_user", "save_user", "delete_user"];

fn main() {
    tauri_plugin::Builder::new(COMMANDS)
        .build();
}

This generates:

• allow-get-user / deny-get-user
• allow-save-user / deny-save-user
• allow-delete-user / deny-delete-user

Default Permission Set

Create permissions/default.toml:

[default]
description = "Default permissions for my-plugin"
permissions = [
  "allow-get-user",
  "allow-save-user"
]

Remote Access Configuration

Allow remote URLs to access Tauri APIs (use with caution):

{
  "identifier": "remote-capability",
  "windows": ["main"],
  "remote": {
    "urls": ["https://*.myapp.com"]
  },
  "permissions": [
    "core:default"
  ]
}

Security Warning: Linux and Android cannot distinguish iframe requests from window requests.

Configuration in tauri.conf.json

Reference capabilities by identifier:

{
  "app": {
    "security": {
      "capabilities": ["main-capability", "admin-capability"]
    }
  }
}

Or inline capabilities directly:

{
  "app": {
    "security": {
      "capabilities": [
        {
          "identifier": "inline-capability",
          "windows": ["*"],
          "permissions": ["core:default"]
        }
      ]
    }
  }
}

Troubleshooting

Common Errors

"Not allowed on this command"

• Verify command permission is in capability
• Check scope includes the target path
• Ensure capability targets correct window

Permission not found

• Check identifier spelling (lowercase only)
• Verify plugin is installed
• Run cargo build to regenerate permissions

Debugging Permissions

1. Check generated schema: src-tauri/gen/schemas/
2. Review capability files load correctly
3. Verify window names match capability targets
4. Check deny rules are not blocking access

Best Practices

1. Principle of Least Privilege: Only grant permissions actually needed
2. Use Specific Scopes: Prefer $APPDATA/* over $HOME/**
3. Deny Sensitive Paths: Always deny access to .ssh, credentials, etc.
4. Separate Capabilities: Use different capabilities for different window types
5. Document Custom Permissions: Include clear descriptions
6. Review Plugin Defaults: Understand what default permissions grant
7. Platform-Specific Config: Use platform targeting for OS-specific needs