CSP: worker-src

HTTP の Content-Security-Policy (CSP) worker-src ディレクティブは、 Worker, SharedWorker, ServiceWorker スクリプトの有効なソースを指定します。

CSP バージョン 3
ディレクティブ種別 フェッチディレクティブ

このディレクティブがない場合、ユーザーエージェントはワーカーの実行の管理のために、最初に child-src ディレクティブ、次に script-src ディレクティブ、最後に default-src ディレクティブを探します。

Chrome 59 以降は child-src ディレクティブを飛ばします。

Edge 17 は script-src ディレクティブを飛ばします (bug)。


worker-src ポリシーには1つ以上のソースを指定することができます。

Content-Security-Policy: worker-src <source>;
Content-Security-Policy: worker-src <source> <source>;


<source> can be one of the following:

Internet hosts by name or IP address, as well as an optional URL scheme and/or port number. The site's address may include an optional leading wildcard (the asterisk character, '*'), and you may use a wildcard (again, '*') as the port number, indicating that all legal ports are valid for the source.
  • http://*.example.com: Matches all attempts to load from any subdomain of example.com using the http: URL scheme.
  • mail.example.com:443: Matches all attempts to access port 443 on mail.example.com.
  • https://store.example.com: Matches all attempts to access store.example.com using https:.
A schema such as 'http:' or 'https:'. The colon is required, single quotes shouldn't be used. You can also specify data schemas (not recommended).
  • data: Allows data: URIs to be used as a content source. This is insecure; an attacker can also inject arbitrary data: URIs. Use this sparingly and definitely not for scripts.
  • mediastream: Allows mediastream: URIs to be used as a content source.
  • blob: Allows blob: URIs to be used as a content source.
  • filesystem: Allows filesystem: URIs to be used as a content source.
Refers to the origin from which the protected document is being served, including the same URL scheme and port number. You must include the single quotes. Some browsers specifically exclude blob and filesystem from source directives. Sites needing to allow these content types can specify them using the Data attribute.
Allows the use of inline resources, such as inline <script> elements, javascript: URLs, inline event handlers, and inline <style> elements. You must include the single quotes.
Allows the use of eval() and similar methods for creating code from strings. You must include the single quotes.
Refers to the empty set; that is, no URLs match. The single quotes are required.
A whitelist for specific inline scripts using a cryptographic nonce (number used once). The server must generate a unique nonce value each time it transmits a policy. It is critical to provide an unguessable nonce, as bypassing a resource’s policy is otherwise trivial. See unsafe inline script for an example. Specifying nonce makes a modern browser ignore 'unsafe-inline' which could still be set for older browsers without nonce support.
A sha256, sha384 or sha512 hash of scripts or styles. The use of this source consists of two portions separated by a dash: the encryption algorithm used to create the hash and the base64-encoded hash of the script or style. When generating the hash, don't include the <script> or <style> tags and note that capitalization and whitespace matter, including leading or trailing whitespace. See unsafe inline script for an example. In CSP 2.0 this applied only to inline scripts. CSP 3.0 allows it in the case of script-src for external scripts.
The strict-dynamic source expression specifies that the trust explicitly given to a script present in the markup, by accompanying it with a nonce or a hash, shall be propagated to all the scripts loaded by that root script. At the same time, any whitelist or source expressions such as 'self' or 'unsafe-inline' will be ignored. See script-src for an example.


この CSP ヘッダーが与えられている時、

Content-Security-Policy: worker-src https://example.com/

Worker, SharedWorker, ServiceWorker はブロックされ、読み込まれません。

  var blockedWorker = new Worker("data:application/javascript,..."); 
  blockedWorker = new SharedWorker("https://not-example.com/"); 


仕様書 状態 備考
Content Security Policy Level 3
worker-src の定義
草案 初回定義。


機能ChromeEdgeFirefoxInternet ExplorerOperaSafari
基本対応591 なし58 なし48 なし
機能Android webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
基本対応591591 なし5848 なし7.0

1. Chrome 59 and higher skips the deprecated child-src directive.



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