From 62babcaf0a88edb081529977981cf8865b32ea21 Mon Sep 17 00:00:00 2001
From: Robert Ransom <rransom.8774@gmail.com>
Date: Sat, 15 Sep 2012 03:52:13 -0700
Subject: [PATCH] Implement and use crypto_pk_eq_keys

---
 src/common/crypto.c  | 12 ++++++++++++
 src/common/crypto.h  |  1 +
 src/or/rendservice.c |  2 +-
 src/or/router.c      | 11 +++++------
 src/or/routerlist.c  |  4 ++--
 5 files changed, 21 insertions(+), 9 deletions(-)

diff --git a/src/common/crypto.c b/src/common/crypto.c
index 5b5fb755b2..283b00575d 100644
--- a/src/common/crypto.c
+++ b/src/common/crypto.c
@@ -774,6 +774,18 @@ crypto_pk_cmp_keys(crypto_pk_t *a, crypto_pk_t *b)
   return BN_cmp((a->key)->e, (b->key)->e);
 }
 
+/** Compare the public-key components of a and b.  Return non-zero iff
+ * a==b.  A NULL key is considered to be distinct from all non-NULL
+ * keys, and equal to itself.
+ *
+ *  Note that this may leak information about the keys through timing.
+ */
+int
+crypto_pk_eq_keys(crypto_pk_t *a, crypto_pk_t *b)
+{
+  return (crypto_pk_cmp_keys(a, b) == 0);
+}
+
 /** Return the size of the public key modulus in <b>env</b>, in bytes. */
 size_t
 crypto_pk_keysize(crypto_pk_t *env)
diff --git a/src/common/crypto.h b/src/common/crypto.h
index 456a61173f..e8248508fc 100644
--- a/src/common/crypto.h
+++ b/src/common/crypto.h
@@ -148,6 +148,7 @@ int crypto_pk_write_private_key_to_filename(crypto_pk_t *env,
 
 int crypto_pk_check_key(crypto_pk_t *env);
 int crypto_pk_cmp_keys(crypto_pk_t *a, crypto_pk_t *b);
+int crypto_pk_eq_keys(crypto_pk_t *a, crypto_pk_t *b);
 size_t crypto_pk_keysize(crypto_pk_t *env);
 int crypto_pk_num_bits(crypto_pk_t *env);
 crypto_pk_t *crypto_pk_dup_key(crypto_pk_t *orig);
diff --git a/src/or/rendservice.c b/src/or/rendservice.c
index 0bfa17d108..0fa04b63fe 100644
--- a/src/or/rendservice.c
+++ b/src/or/rendservice.c
@@ -2730,7 +2730,7 @@ find_intro_point(origin_circuit_t *circ)
   if (service == NULL) return NULL;
 
   SMARTLIST_FOREACH(service->intro_nodes, rend_intro_point_t *, intro_point,
-    if (crypto_pk_cmp_keys(intro_point->intro_key, circ->intro_key) == 0) {
+    if (crypto_pk_eq_keys(intro_point->intro_key, circ->intro_key)) {
       return intro_point;
     });
 
diff --git a/src/or/router.c b/src/or/router.c
index 052ed38074..2e80c54680 100644
--- a/src/or/router.c
+++ b/src/or/router.c
@@ -87,7 +87,7 @@ static authority_cert_t *legacy_key_certificate = NULL;
 static void
 set_onion_key(crypto_pk_t *k)
 {
-  if (onionkey && !crypto_pk_cmp_keys(onionkey, k)) {
+  if (onionkey && crypto_pk_eq_keys(onionkey, k)) {
     /* k is already our onion key; free it and return */
     crypto_pk_free(k);
     return;
@@ -155,12 +155,11 @@ assert_identity_keys_ok(void)
   if (public_server_mode(get_options())) {
     /* assert that we have set the client and server keys to be equal */
     tor_assert(server_identitykey);
-    tor_assert(0==crypto_pk_cmp_keys(client_identitykey, server_identitykey));
+    tor_assert(crypto_pk_eq_keys(client_identitykey, server_identitykey));
   } else {
     /* assert that we have set the client and server keys to be unequal */
     if (server_identitykey)
-      tor_assert(0!=crypto_pk_cmp_keys(client_identitykey,
-                                       server_identitykey));
+      tor_assert(!crypto_pk_eq_keys(client_identitykey, server_identitykey));
   }
 }
 
@@ -400,7 +399,7 @@ load_authority_keyset(int legacy, crypto_pk_t **key_out,
     log_warn(LD_DIR, "Unable to parse certificate in %s", fname);
     goto done;
   }
-  if (crypto_pk_cmp_keys(signing_key, parsed->signing_key) != 0) {
+  if (!crypto_pk_eq_keys(signing_key, parsed->signing_key)) {
     log_warn(LD_DIR, "Stored signing key does not match signing key in "
              "certificate");
     goto done;
@@ -2008,7 +2007,7 @@ router_dump_router_to_string(char *s, size_t maxlen, routerinfo_t *router,
   const or_options_t *options = get_options();
 
   /* Make sure the identity key matches the one in the routerinfo. */
-  if (crypto_pk_cmp_keys(ident_key, router->identity_pkey)) {
+  if (!crypto_pk_eq_keys(ident_key, router->identity_pkey)) {
     log_warn(LD_BUG,"Tried to sign a router with a private key that didn't "
              "match router's public key!");
     return -1;
diff --git a/src/or/routerlist.c b/src/or/routerlist.c
index 98357d6a38..5327622f1b 100644
--- a/src/or/routerlist.c
+++ b/src/or/routerlist.c
@@ -4529,8 +4529,8 @@ router_differences_are_cosmetic(const routerinfo_t *r1, const routerinfo_t *r2)
       r1->ipv6_orport != r2->ipv6_orport ||
       r1->dir_port != r2->dir_port ||
       r1->purpose != r2->purpose ||
-      crypto_pk_cmp_keys(r1->onion_pkey, r2->onion_pkey) ||
-      crypto_pk_cmp_keys(r1->identity_pkey, r2->identity_pkey) ||
+      !crypto_pk_eq_keys(r1->onion_pkey, r2->onion_pkey) ||
+      !crypto_pk_eq_keys(r1->identity_pkey, r2->identity_pkey) ||
       strcasecmp(r1->platform, r2->platform) ||
       (r1->contact_info && !r2->contact_info) || /* contact_info is optional */
       (!r1->contact_info && r2->contact_info) ||