Fixed #36532 -- Added Content Security Policy view decorators to override or disable policies.

Co-authored-by: Natalia <124304+nessita@users.noreply.github.com>

3 files changed, 54 insertions, 13 deletions

diff --git a/django/middleware/csp.py b/django/middleware/csp.py
index e1c66ada5a..ba08cfff0c 100644
--- a/django/middleware/csp.py
+++ b/django/middleware/csp.py
@@ -1,5 +1,3 @@
-from http import HTTPStatus
-
 from django.conf import settings
 from django.utils.csp import CSP, LazyNonce, build_policy
 from django.utils.deprecation import MiddlewareMixin
@@ -14,22 +12,21 @@ class ContentSecurityPolicyMiddleware(MiddlewareMixin):
         request._csp_nonce = LazyNonce()
 
     def process_response(self, request, response):
-        # In DEBUG mode, exclude CSP headers for specific status codes that
-        # trigger the debug view.
-        exempted_status_codes = {
-            HTTPStatus.NOT_FOUND,
-            HTTPStatus.INTERNAL_SERVER_ERROR,
-        }
-        if settings.DEBUG and response.status_code in exempted_status_codes:
-            return response
-
         nonce = get_nonce(request)
+
+        sentinel = object()
+        if (csp_config := getattr(response, "_csp_config", sentinel)) is sentinel:
+            csp_config = settings.SECURE_CSP
+        if (csp_ro_config := getattr(response, "_csp_ro_config", sentinel)) is sentinel:
+            csp_ro_config = settings.SECURE_CSP_REPORT_ONLY
+
         for header, config in [
-            (CSP.HEADER_ENFORCE, settings.SECURE_CSP),
-            (CSP.HEADER_REPORT_ONLY, settings.SECURE_CSP_REPORT_ONLY),
+            (CSP.HEADER_ENFORCE, csp_config),
+            (CSP.HEADER_REPORT_ONLY, csp_ro_config),
         ]:
             # If headers are already set on the response, don't overwrite them.
             # This allows for views to set their own CSP headers as needed.
+            # An empty config means CSP headers are not added to the response.
             if config and header not in response:
                 response.headers[str(header)] = build_policy(config, nonce)
 
diff --git a/django/views/debug.py b/django/views/debug.py
index 75f30ca601..5a1b4aee91 100644
--- a/django/views/debug.py
+++ b/django/views/debug.py
@@ -18,6 +18,7 @@ from django.utils.encoding import force_str
 from django.utils.module_loading import import_string
 from django.utils.regex_helper import _lazy_re_compile
 from django.utils.version import get_docs_version
+from django.views.decorators.csp import csp_override, csp_report_only_override
 from django.views.decorators.debug import coroutine_functions_to_sensitive_variables
 
 # Minimal Django templates engine to render the error templates
@@ -59,6 +60,8 @@ class CallableSettingWrapper:
         return repr(self._wrapped)
 
 
+@csp_override({})
+@csp_report_only_override({})
 def technical_500_response(request, exc_type, exc_value, tb, status_code=500):
     """
     Create a technical server error response. The last three arguments are
@@ -606,6 +609,8 @@ class ExceptionReporter:
             tb = tb.tb_next
 
 
+@csp_override({})
+@csp_report_only_override({})
 def technical_404_response(request, exception):
     """Create a technical 404 error response. `exception` is the Http404."""
     try:
diff --git a/django/views/decorators/csp.py b/django/views/decorators/csp.py
new file mode 100644
index 0000000000..9033d9cdf0
--- /dev/null
+++ b/django/views/decorators/csp.py
@@ -0,0 +1,39 @@
+from functools import wraps
+
+from asgiref.sync import iscoroutinefunction
+
+
+def _make_csp_decorator(config_attr_name, config_attr_value):
+    """General CSP override decorator factory."""
+
+    if not isinstance(config_attr_value, dict):
+        raise TypeError("CSP config should be a mapping.")
+
+    def decorator(view_func):
+        @wraps(view_func)
+        async def _wrapped_async_view(request, *args, **kwargs):
+            response = await view_func(request, *args, **kwargs)
+            setattr(response, config_attr_name, config_attr_value)
+            return response
+
+        @wraps(view_func)
+        def _wrapped_sync_view(request, *args, **kwargs):
+            response = view_func(request, *args, **kwargs)
+            setattr(response, config_attr_name, config_attr_value)
+            return response
+
+        if iscoroutinefunction(view_func):
+            return _wrapped_async_view
+        return _wrapped_sync_view
+
+    return decorator
+
+
+def csp_override(config):
+    """Override the Content-Security-Policy header for a view."""
+    return _make_csp_decorator("_csp_config", config)
+
+
+def csp_report_only_override(config):
+    """Override the Content-Security-Policy-Report-Only header for a view."""
+    return _make_csp_decorator("_csp_ro_config", config)