1 files changed, 134 insertions, 0 deletions
diff --git a/src/hydrilla/proxy/policies/rule.py b/src/hydrilla/proxy/policies/rule.py
new file mode 100644
index 0000000..eb70147
--- /dev/null
+++ b/src/hydrilla/proxy/policies/rule.py
@@ -0,0 +1,134 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+# Policies for blocking and allowing JS in pages fetched with HTTP.
+#
+# This file is part of Hydrilla&Haketilo.
+#
+# Copyright (C) 2022 Wojtek Kosior
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+#
+#
+# I, Wojtek Kosior, thereby promise not to sue for violation of this
+# file's license. Although I request that you do not make use this code
+# in a proprietary program, I am not going to enforce this in court.
+
+"""
+.....
+"""
+
+# Enable using with Python 3.7.
+from __future__ import annotations
+
+import dataclasses as dc
+import typing as t
+
+from ...url_patterns import ParsedPattern
+from .. import csp
+from .. import state
+from . import base
+
+
+class AllowPolicy(base.Policy):
+    """...."""
+    priority: t.ClassVar[base.PolicyPriority] = base.PolicyPriority._TWO
+
+class BlockPolicy(base.Policy):
+    """...."""
+    process_response: t.ClassVar[bool] = True
+
+    priority: t.ClassVar[base.PolicyPriority] = base.PolicyPriority._TWO
+
+    def _modify_headers(self, response_info: base.ResponseInfo) \
+        -> t.Iterable[tuple[bytes, bytes]]:
+        """...."""
+        csp_policies = csp.extract(response_info.headers)
+
+        for header_name, header_value in response_info.headers.items():
+            if header_name.lower() not in csp.header_names_and_dispositions:
+                yield header_name.encode(), header_value.encode()
+
+        for policy in csp_policies:
+            if policy.disposition != 'enforce':
+                continue
+
+            directives = policy.directives.mutate()
+            directives.pop('report-to',  None)
+            directives.pop('report-uri', None)
+
+            policy = dc.replace(policy, directives=directives.finish())
+
+            yield policy.header_name.encode(), policy.serialize().encode()
+
+        extra_csp = ';'.join((
+            "script-src 'none'",
+            "script-src-elem 'none'",
+            "script-src-attr 'none'"
+        ))
+
+        yield b'Content-Security-Policy', extra_csp.encode()
+
+
+    def consume_response(self, response_info: base.ResponseInfo) \
+        -> base.ProducedResponse:
+        """...."""
+        new_response = response_info.make_produced_response()
+
+        new_headers = self._modify_headers(response_info)
+
+        return dc.replace(new_response, headers=new_headers)
+
+@dc.dataclass(frozen=True)
+class RuleAllowPolicy(AllowPolicy):
+    """...."""
+    pattern: ParsedPattern
+
+
+@dc.dataclass(frozen=True)
+class RuleBlockPolicy(BlockPolicy):
+    """...."""
+    pattern: ParsedPattern
+
+
+@dc.dataclass(frozen=True, unsafe_hash=True) # type: ignore[misc]
+class RulePolicyFactory(base.PolicyFactory):
+    """...."""
+    pattern: ParsedPattern
+
+    def __lt__(self, other: base.PolicyFactory) -> bool:
+        """...."""
+        if type(other) is type(self):
+            return super().__lt__(other)
+
+        assert isinstance(other, RulePolicyFactory)
+
+        return self.pattern < other.pattern
+
+
+@dc.dataclass(frozen=True, unsafe_hash=True) # type: ignore[misc]
+class RuleBlockPolicyFactory(RulePolicyFactory):
+    """...."""
+    def make_policy(self, haketilo_state: state.HaketiloState) \
+        -> RuleBlockPolicy:
+        """...."""
+        return RuleBlockPolicy(self.pattern)
+
+
+@dc.dataclass(frozen=True, unsafe_hash=True) # type: ignore[misc]
+class RuleAllowPolicyFactory(RulePolicyFactory):
+    """...."""
+    def make_policy(self, haketilo_state: state.HaketiloState) \
+        -> RuleAllowPolicy:
+        """...."""
+        return RuleAllowPolicy(self.pattern)