tor

commit a79046f40a515473ece5eb74aa72f82511571fe0
parent 536b5c8059bc3356edb8687c423c5966a2729b6d
Author: Nick Mathewson <nickm@torproject.org>
Date:   Tue,  1 Mar 2022 11:53:10 -0500

Fix logic for whether a channel's Ed25519 ID is changing

The previous code would notice if we were changing from one identity
to another, but not if we were changing from no identity to having
an identity.  This problem caused a bug (spotted by cypherpunks in
ticket #40563) where if we created a channel for a circuit request
that doesn't include an Ed25519 identity, we won't be able to use
that channel later for requests that _do_ list Ed25519.

Fix for 40563; bugfix on 0.3.0.1-alpha.

Diffstat:
M
src/core/or/connection_or.c
 | 
5
+++--

1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/src/core/or/connection_or.c b/src/core/or/connection_or.c
@@ -179,8 +179,9 @@ connection_or_set_identity_digest(or_connection_t *conn,
     chan && !ed25519_public_key_is_zero(&chan->ed25519_identity);
   const int rsa_changed =
     tor_memneq(conn->identity_digest, rsa_digest, DIGEST_LEN);
-  const int ed_changed = ed_id_was_set &&
-    (!ed_id || !ed25519_pubkey_eq(ed_id, &chan->ed25519_identity));
+  const int ed_changed = (!ed_id_was_set && ed_id) ||
+    (ed_id_was_set && ed_id && chan &&
+     !ed25519_pubkey_eq(ed_id, &chan->ed25519_identity));
 
   if (BUG(rsa_changed && rsa_id_was_set))
     return;