# ----------------------------------------------------------------------
# | Cross Origin Policy                                                |
# ----------------------------------------------------------------------

# Set strict a Cross Origin Policy to mitigate information leakage.
#
# (1) Cross-Origin-Embedder-Policy prevents a document from loading any
#     cross-origin resources that don’t explicitly grant the document
#     permission.
#     https://html.spec.whatwg.org/multipage/origin.html#coep
#     https://owasp.org/www-project-secure-headers/#cross-origin-embedder-policy
#     https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cross-Origin-Embedder-Policy
#
# (2) Cross-Origin-Opener-Policy allows you to ensure a top-level document does
#     not share a browsing context group with cross-origin documents.
#     https://html.spec.whatwg.org/multipage/origin.html#cross-origin-opener-policies
#     https://owasp.org/www-project-secure-headers/#cross-origin-opener-policy
#     https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cross-Origin-Opener-Policy
#
# (3) Cross-Origin-Resource-Policy allows to define a policy that lets web
#     sites and applications opt in to protection against certain requests from
#     other origins, to mitigate speculative side-channel attacks.
#     https://fetch.spec.whatwg.org/#cross-origin-resource-policy-header
#     https://owasp.org/www-project-secure-headers/#cross-origin-resource-policy
#     https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cross-Origin-Resource-Policy
#     https://resourcepolicy.fyi/
#
# To check your Cross Origin Policy, you can use an online service, such as:
# https://securityheaders.com/
# https://observatory.mozilla.org/
#
# https://web.dev/coop-coep/
# https://web.dev/why-coop-coep/
# https://web.dev/cross-origin-isolation-guide/
# https://scotthelme.co.uk/coop-and-coep/

# (1)
add_header Cross-Origin-Embedder-Policy $coep_policy always;

# (2)
add_header Cross-Origin-Opener-Policy $coop_policy always;

# (3)
add_header Cross-Origin-Resource-Policy $corp_policy always;