CSP: child-src

La directive HTTP Content-Security-Policy (CSP) child-src définit les sources valides de web workers et de contextes de navigations imbriqués chargés au moyen d'éléments tels que <frame> et <iframe>. Pour les workers, les requêtes conformes sont traitées comme des erreurs de réseau fatales par l'agent utilisateur.

Version de CSP 2
Type de directive Fetch directive
default-src par défaut Oui, si cette directive est absente, l'agent utilisateur consultera la directive default-src

Syntaxe

Une ou plusieurs sources peuvent être autorisées pour cette directive :

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

Sources

<source> can be one of the following:

<host-source>

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. Examples:

  • 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:.
  • *.example.com: Matches all attempts to load from any subdomain of example.com using the current protocol.
<scheme-source>

A scheme such as http: or https:. The colon is required. Unlike other values below, single quotes shouldn't be used. You can also specify data schemes (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.
'self'

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.

'unsafe-eval'

Allows the use of eval() and similar methods for creating code from strings. You must include the single quotes.

'unsafe-hashes'

Allows enabling specific inline event handlers. If you only need to allow inline event handlers and not inline <script> elements or javascript: URLs, this is a safer method than using the unsafe-inline expression.

'unsafe-inline'

Allows the use of inline resources, such as inline <script> elements, javascript: URLs, inline event handlers, and inline <style> elements. The single quotes are required.

'none'

Refers to the empty set; that is, no URLs match. The single quotes are required.

'nonce-<base64-value>'

An allow-list 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.

Note: The CSP nonce source can only be applied to nonceable elements (e.g., as the <img> element has no nonce attribute, there is no way to associate it with this CSP source).

'<hash-algorithm>-<base64-value>'

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 is applied only to inline scripts. CSP 3.0 allows it in the case of script-src for external scripts.

'strict-dynamic'

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 allow-list or source expressions such as 'self' or 'unsafe-inline' are ignored. See script-src for an example.

'report-sample'

Requires a sample of the violating code to be included in the violation report.

Exemples

Cas de violation

Soit cet en-tête CSP :

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

Cet <iframe> et ce worker seront bloqués et ne se chargeront pas :

<iframe src="https://not-example.com"></iframe>

<script>
  var blockedWorker = new Worker("data:application/javascript,...");
</script>

Spécifications

Spécification Statut Commentaire
Content Security Policy Level 3
La définition de 'child-src' dans cette spécification.
Version de travail Inchangé.
Content Security Policy Level 2
La définition de 'child-src' dans cette spécification.
Recommendation Définition initiale.

Compatibilité des navigateurs

BCD tables only load in the browser

Voir aussi