Important: #104549 - Introduce site-specific Content-Security-Policy-Disposition 

See forge#104549

Description 

The feature flags $GLOBALS['TYPO3_CONF_VARS']['SYS']['features']['security.frontend.enforceContentSecurityPolicy'] and $GLOBALS['TYPO3_CONF_VARS']['SYS']['features']['security.frontend.reportContentSecurityPolicy'] apply Content-Security-Policy headers to any frontend site. The dedicated sites/<my-site>/csp.yaml can now be used as alternative to declare the desired disposition of Content-Security-Policy and Content-Security-Policy-Report-Only individually.

It now is also possible, to apply both Content-Security-Policy and Content-Security-Policy-Report-Only HTTP headers at the same time with different directives for a particular site. Besides that it is possible to disable the disposition completely for a site.

The following new configuration schemes were introduced for sites/<my-site>/csp.yaml:

  • active (false) for disabling CSP for a particular site, which overrules any other setting for enforce or report
  • enforce (bool|disposition-array) for compiling the Content-Security-Policy HTTP header
  • report (bool|disposition-array) for compiling the Content-Security-Policy-Report-Only HTTP header

The disposition-array for enforce and report allows these properties:

  • inheritDefault (bool) inherits default site-unspecific frontend policy mutations (true per default)
  • includeResolutions (bool) includes dynamic resolutions, as persisted in the database via backend module (true per default)
  • mutations (mutation-item-array) defines additional directive mutations to be applied to the specific site
  • packages (package-item-array) defines packages/extensions whose static CSP mutations shall be dropped or included

Example: Disable Content-Security-Policy 

The following example would completely disable CSP for a particular site.

config/sites/<my-site>/csp.yaml 
# `active` is enabled per default if omitted
active: false
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Example: Use report disposition 

The following example would dispose only Content-Security-Policy-Report-Only for a particular site (since the enforce property is not given).

config/sites/<my-site>/csp.yaml 
report:
  # `inheritDefault` is enabled per default if omitted
  inheritDefault: true
  mutations:
   - mode: extend
     directive: img-src
     sources:
      - https://*.typo3.org
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The following example is equivalent to the previous, but shows that the legacy configuration (having inheritDefault and mutations on the top-level) is still supported.

The effective HTTP headers would then be resolved from the active feature flags security.frontend.enforceContentSecurityPolicy and security.frontend.reportContentSecurityPolicy - in case both flags are active, both HTTP headers Content-Security-Policy and Content-Security-Policy-Read-Only would be used.

config/sites/<my-site>/csp.yaml 
# `inheritDefault` is enabled per default if omitted
inheritDefault: true
mutations:
 - mode: extend
   directive: img-src
   sources:
    - https://*.typo3.org
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Example: Use enforce and report dispositions at the same time 

The following example would dispose Content-Security-Policy (enforce) and Content-Security-Policy-Report-Only (report) for a particular site.

This allows to test new CSP directives in the frontend - the example drops the static CSP directives of the package my-vendor/my-package in the enforced disposition and only applies it to the reporting disposition.

config/sites/<my-site>/csp.yaml 
enforce:
  # `inheritDefault` is enabled per default if omitted
  inheritDefault: true
  # `includeResolutions` is enabled per default if omitted
  includeResolutions: true
  mutations:
    - mode: extend
      directive: img-src
      sources:
        - https://*.typo3.org
  packages:
    # all (`*`) packages shall be included (`true`)
    '*': true
    # the package `my-vendor/my-package` shall be dropped (`false`)
    my-vendor/my-package: false

report:
  # `inheritDefault` is enabled per default if omitted
  inheritDefault: true
  # `includeResolutions` is enabled per default if omitted
  includeResolutions: true
  mutations:
    - mode: extend
      directive: img-src
      sources:
        - https://*.my-vendor.example.org/
  # the `packages` section can be omitted in this case, since all packages
  # listed there shall be included - which is the default behavior in case
  # `packages` would not be configured
  packages:
    # all (`*`) packages shall be included (`true`)
    '*': true
    # the package `my-vendor/my-package` shall be included (`true`)
    my-vendor/my-package: true
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