From e040ea5ec78571c4fe15cb812213c9fdfcece3c8 Mon Sep 17 00:00:00 2001
From: Alexis Sellier <alexis@radicle.xyz>
Date: Sat, 27 Aug 2022 14:46:22 +0200
Subject: [PATCH] node: Don't allow timestamps with too much delta

Signed-off-by: Alexis Sellier <self@cloudhead.io>
---
 node/src/protocol.rs   | 12 ++++++++----
 node/src/test/tests.rs |  6 ++++--
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/node/src/protocol.rs b/node/src/protocol.rs
index c425d0e0..852d542c 100644
--- a/node/src/protocol.rs
+++ b/node/src/protocol.rs
@@ -37,6 +37,7 @@ pub const ANNOUNCE_INTERVAL: LocalDuration = LocalDuration::from_secs(30);
 pub const SYNC_INTERVAL: LocalDuration = LocalDuration::from_secs(60);
 pub const PRUNE_INTERVAL: LocalDuration = LocalDuration::from_mins(30);
 pub const MAX_CONNECTION_ATTEMPTS: usize = 3;
+pub const MAX_TIME_DELTA: LocalDuration = LocalDuration::from_mins(60);
 
 /// Commands sent to the protocol by the operator.
 #[derive(Debug)]
@@ -878,20 +879,23 @@ impl Peer {
                 let inventory = Message::inventory(ctx).unwrap();
                 ctx.write(self.addr, inventory);
             }
-            Message::Inventory { timestamp: 0, .. } => {
-                return Err(PeerError::InvalidTimestamp(0));
-            }
             Message::Inventory {
                 timestamp,
                 inv,
                 origin,
             } => {
+                let now = ctx.clock.local_time();
                 let last = ctx
                     .timestamps
                     .entry(self.id())
                     .or_insert_with(Timestamp::default);
 
-                // Discard inventory messages from timestamps in the past.
+                // Don't allow messages from too far in the past or future.
+                if timestamp.abs_diff(now.as_secs()) > MAX_TIME_DELTA.as_secs() {
+                    return Err(PeerError::InvalidTimestamp(timestamp));
+                }
+                // Discard inventory messages we've already seen, otherwise update
+                // out last seen time.
                 if timestamp > *last {
                     *last = timestamp;
                 } else {
diff --git a/node/src/test/tests.rs b/node/src/test/tests.rs
index 25f95fa2..92d6786f 100644
--- a/node/src/test/tests.rs
+++ b/node/src/test/tests.rs
@@ -122,12 +122,14 @@ fn test_inventory_fetch() {
 fn test_inventory_relay_bad_timestamp() {
     let mut alice = Peer::new("alice", [7, 7, 7, 7], MockStorage::empty());
     let bob = Peer::new("bob", [8, 8, 8, 8], MockStorage::empty());
+    let two_hours = 3600 * 2;
+    let timestamp = alice.local_time.as_secs() - two_hours;
 
     alice.connect_to(&bob.addr());
     alice.receive(
         &bob.addr(),
         Message::Inventory {
-            timestamp: 0,
+            timestamp,
             inv: vec![],
             origin: None,
         },
@@ -135,7 +137,7 @@ fn test_inventory_relay_bad_timestamp() {
     assert_matches!(
         alice.outbox().next(),
         Some(Io::Disconnect(addr, DisconnectReason::Error(PeerError::InvalidTimestamp(t))))
-        if addr == bob.addr() && t == 0
+        if addr == bob.addr() && t == timestamp
     );
 }