From 14f13babb00d64009b11ef822ebe6fafe044eebd Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>
Date: Wed, 5 Jun 2019 10:38:25 +0100
Subject: [PATCH] Add a test room version where we enforce key validity (#5348)

---
 changelog.d/5348.bugfix               |  1 +
 synapse/api/room_versions.py          | 20 +++++++++-----
 synapse/federation/federation_base.py | 39 ++++++++++++++++-----------
 3 files changed, 38 insertions(+), 22 deletions(-)
 create mode 100644 changelog.d/5348.bugfix

diff --git a/changelog.d/5348.bugfix b/changelog.d/5348.bugfix
new file mode 100644
index 0000000000..8d396c7990
--- /dev/null
+++ b/changelog.d/5348.bugfix
@@ -0,0 +1 @@
+Add a new room version where the timestamps on events are checked against the validity periods on signing keys.
\ No newline at end of file
diff --git a/synapse/api/room_versions.py b/synapse/api/room_versions.py
index 4085bd10b9..501cdfb6a4 100644
--- a/synapse/api/room_versions.py
+++ b/synapse/api/room_versions.py
@@ -50,6 +50,7 @@ class RoomVersion(object):
     disposition = attr.ib()     # str; one of the RoomDispositions
     event_format = attr.ib()    # int; one of the EventFormatVersions
     state_res = attr.ib()       # int; one of the StateResolutionVersions
+    enforce_key_validity = attr.ib()  # bool
 
 
 class RoomVersions(object):
@@ -58,30 +59,35 @@ class RoomVersions(object):
         RoomDisposition.STABLE,
         EventFormatVersions.V1,
         StateResolutionVersions.V1,
-    )
-    STATE_V2_TEST = RoomVersion(
-        "state-v2-test",
-        RoomDisposition.UNSTABLE,
-        EventFormatVersions.V1,
-        StateResolutionVersions.V2,
+        enforce_key_validity=False,
     )
     V2 = RoomVersion(
         "2",
         RoomDisposition.STABLE,
         EventFormatVersions.V1,
         StateResolutionVersions.V2,
+        enforce_key_validity=False,
     )
     V3 = RoomVersion(
         "3",
         RoomDisposition.STABLE,
         EventFormatVersions.V2,
         StateResolutionVersions.V2,
+        enforce_key_validity=False,
     )
     V4 = RoomVersion(
         "4",
         RoomDisposition.STABLE,
         EventFormatVersions.V3,
         StateResolutionVersions.V2,
+        enforce_key_validity=False,
+    )
+    VDH_TEST_KEY_VALIDITY = RoomVersion(
+        "vdh-test-key-validity",
+        RoomDisposition.UNSTABLE,
+        EventFormatVersions.V3,
+        StateResolutionVersions.V2,
+        enforce_key_validity=False,
     )
 
 
@@ -90,7 +96,7 @@ KNOWN_ROOM_VERSIONS = {
         RoomVersions.V1,
         RoomVersions.V2,
         RoomVersions.V3,
-        RoomVersions.STATE_V2_TEST,
         RoomVersions.V4,
+        RoomVersions.VDH_TEST_KEY_VALIDITY,
     )
 }   # type: dict[str, RoomVersion]
diff --git a/synapse/federation/federation_base.py b/synapse/federation/federation_base.py
index 4b38f7c759..b541913d82 100644
--- a/synapse/federation/federation_base.py
+++ b/synapse/federation/federation_base.py
@@ -223,9 +223,6 @@ def _check_sigs_on_pdus(keyring, room_version, pdus):
            the signatures are valid, or fail (with a SynapseError) if not.
     """
 
-    # (currently this is written assuming the v1 room structure; we'll probably want a
-    # separate function for checking v2 rooms)
-
     # we want to check that the event is signed by:
     #
     # (a) the sender's server
@@ -257,6 +254,10 @@ def _check_sigs_on_pdus(keyring, room_version, pdus):
         for p in pdus
     ]
 
+    v = KNOWN_ROOM_VERSIONS.get(room_version)
+    if not v:
+        raise RuntimeError("Unrecognized room version %s" % (room_version,))
+
     # First we check that the sender event is signed by the sender's domain
     # (except if its a 3pid invite, in which case it may be sent by any server)
     pdus_to_check_sender = [
@@ -264,10 +265,16 @@ def _check_sigs_on_pdus(keyring, room_version, pdus):
         if not _is_invite_via_3pid(p.pdu)
     ]
 
-    more_deferreds = keyring.verify_json_objects_for_server([
-        (p.sender_domain, p.redacted_pdu_json, 0)
-        for p in pdus_to_check_sender
-    ])
+    more_deferreds = keyring.verify_json_objects_for_server(
+        [
+            (
+                p.sender_domain,
+                p.redacted_pdu_json,
+                p.pdu.origin_server_ts if v.enforce_key_validity else 0,
+            )
+            for p in pdus_to_check_sender
+        ]
+    )
 
     def sender_err(e, pdu_to_check):
         errmsg = "event id %s: unable to verify signature for sender %s: %s" % (
@@ -287,20 +294,22 @@ def _check_sigs_on_pdus(keyring, room_version, pdus):
     # event id's domain (normally only the case for joins/leaves), and add additional
     # checks. Only do this if the room version has a concept of event ID domain
     # (ie, the room version uses old-style non-hash event IDs).
-    v = KNOWN_ROOM_VERSIONS.get(room_version)
-    if not v:
-        raise RuntimeError("Unrecognized room version %s" % (room_version,))
-
     if v.event_format == EventFormatVersions.V1:
         pdus_to_check_event_id = [
             p for p in pdus_to_check
             if p.sender_domain != get_domain_from_id(p.pdu.event_id)
         ]
 
-        more_deferreds = keyring.verify_json_objects_for_server([
-            (get_domain_from_id(p.pdu.event_id), p.redacted_pdu_json, 0)
-            for p in pdus_to_check_event_id
-        ])
+        more_deferreds = keyring.verify_json_objects_for_server(
+            [
+                (
+                    get_domain_from_id(p.pdu.event_id),
+                    p.redacted_pdu_json,
+                    p.pdu.origin_server_ts if v.enforce_key_validity else 0,
+                )
+                for p in pdus_to_check_event_id
+            ]
+        )
 
         def event_err(e, pdu_to_check):
             errmsg = (