From ca42657abb9f794a4912cea8953edaba31f23a0f Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <richard@matrix.org>
Date: Fri, 9 Aug 2024 12:51:36 +0100
Subject: [PATCH] crypto: Log the received device keys on an encrypted olm
 message

Attempt to summarise the received keys.
---
 crates/matrix-sdk-crypto/src/machine/mod.rs         |  6 +++++-
 crates/matrix-sdk-crypto/src/types/events/olm_v1.rs | 11 +++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/crates/matrix-sdk-crypto/src/machine/mod.rs b/crates/matrix-sdk-crypto/src/machine/mod.rs
index b2c782dbef0..7e951615669 100644
--- a/crates/matrix-sdk-crypto/src/machine/mod.rs
+++ b/crates/matrix-sdk-crypto/src/machine/mod.rs
@@ -1109,7 +1109,11 @@ impl OlmMachine {
         decrypted: &mut OlmDecryptionInfo,
         changes: &mut Changes,
     ) -> OlmResult<()> {
-        debug!("Received a decrypted to-device event");
+        debug!(
+            sender_device_keys =
+                ?decrypted.result.event.sender_device_keys().map(|k| (k.curve25519_key(), k.ed25519_key())).unwrap_or((None, None)),
+            "Received a decrypted to-device event",
+        );
 
         match &*decrypted.result.event {
             AnyDecryptedOlmEvent::RoomKey(e) => {
diff --git a/crates/matrix-sdk-crypto/src/types/events/olm_v1.rs b/crates/matrix-sdk-crypto/src/types/events/olm_v1.rs
index 0ecf19c2268..dc33fffdae7 100644
--- a/crates/matrix-sdk-crypto/src/types/events/olm_v1.rs
+++ b/crates/matrix-sdk-crypto/src/types/events/olm_v1.rs
@@ -148,6 +148,17 @@ impl AnyDecryptedOlmEvent {
             AnyDecryptedOlmEvent::Dummy(e) => e.content.event_type(),
         }
     }
+
+    /// The sender's device keys, if supplied in the message as per MSC4147
+    pub fn sender_device_keys(&self) -> Option<&DeviceKeys> {
+        match self {
+            AnyDecryptedOlmEvent::Custom(_) => None,
+            AnyDecryptedOlmEvent::RoomKey(e) => e.device_keys.as_ref(),
+            AnyDecryptedOlmEvent::ForwardedRoomKey(e) => e.device_keys.as_ref(),
+            AnyDecryptedOlmEvent::SecretSend(e) => e.device_keys.as_ref(),
+            AnyDecryptedOlmEvent::Dummy(e) => e.device_keys.as_ref(),
+        }
+    }
 }
 
 /// An `m.olm.v1.curve25519-aes-sha2` decrypted to-device event.