[tor-commits] [tor/release-0.4.0] Avoid a crash if our "current" and "old" ntor onion keys are equal

[teor at torproject.org]

commit 2da4d64a64a803f4b0a6d56e517b4288bef6c4f8
Author: Nick Mathewson <nickm at torproject.org>
Date:   Wed Sep 18 11:14:45 2019 -0400

    Avoid a crash if our "current" and "old" ntor onion keys are equal
    
    Our dimap code asserts if you try to add the same key twice; this
    can't happen if everything is running smoothly, but it's possible if
    you try to start a relay where secret_onion_key_ntor is the same as
    secret_onion_key_ntor.old.
    
    Fixes bug 30916; bugfix on 0.2.4.8-alpha when ntor keys were
    introduced.
---
 changes/bug30916           | 4 ++++
 src/feature/relay/router.c | 3 ++-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/changes/bug30916 b/changes/bug30916
new file mode 100644
index 000000000..b006bfc75
--- /dev/null
+++ b/changes/bug30916
@@ -0,0 +1,4 @@
+  o Minor bugfixes (relay):
+    - Avoid crashing when starting with a corrupt keys directory where
+      the old ntor key and the new ntor key are identical. Fixes bug 30916;
+      bugfix on 0.2.4.8-alpha.
diff --git a/src/feature/relay/router.c b/src/feature/relay/router.c
index 88a30cef0..1dbaf2ed6 100644
--- a/src/feature/relay/router.c
+++ b/src/feature/relay/router.c
@@ -286,7 +286,8 @@ construct_ntor_key_map(void)
                     tor_memdup(&curve25519_onion_key,
                                sizeof(curve25519_keypair_t)));
   }
-  if (!tor_mem_is_zero((const char*)last_pk, CURVE25519_PUBKEY_LEN)) {
+  if (!tor_mem_is_zero((const char*)last_pk, CURVE25519_PUBKEY_LEN) &&
+      tor_memneq(cur_pk, last_pk, CURVE25519_PUBKEY_LEN)) {
     dimap_add_entry(&m, last_pk,
                     tor_memdup(&last_curve25519_onion_key,
                                sizeof(curve25519_keypair_t)));