Maintain separate server and client identity keys when appropriate.

Fixes a bug described in ticket #988.

1 files changed, 82 insertions, 32 deletions

diff --git a/src/or/router.c b/src/or/router.c
index c59e4b2ca0..a256970f90 100644
--- a/src/or/router.c
+++ b/src/or/router.c
@@ -49,11 +49,15 @@ static crypto_pk_env_t *onionkey=NULL;
 /** Previous private onionskin decryption key: used to decode CREATE cells
  * generated by clients that have an older version of our descriptor. */
 static crypto_pk_env_t *lastonionkey=NULL;
-/** Private "identity key": used to sign directory info and TLS
+/** Private server "identity key": used to sign directory info and TLS
  * certificates. Never changes. */
-static crypto_pk_env_t *identitykey=NULL;
-/** Digest of identitykey. */
-static char identitykey_digest[DIGEST_LEN];
+static crypto_pk_env_t *server_identitykey=NULL;
+/** Digest of server_identitykey. */
+static char server_identitykey_digest[DIGEST_LEN];
+/** Private client "identity key": used to sign bridges' and clients'
+ * outbound TLS certificates. Regenerated on startup and on IP address
+ * change. */
+static crypto_pk_env_t *client_identitykey=NULL;
 /** Signing key used for v3 directory material; only set for authorities. */
 static crypto_pk_env_t *authority_signing_key = NULL;
 /** Key certificate to authenticate v3 directory material; only set for
@@ -123,31 +127,57 @@ get_onion_key_set_at(void)
   return onionkey_set_at;
 }
 
-/** Set the current identity key to k.
+/** Set the current server identity key to <b>k</b>.
  */
 void
-set_identity_key(crypto_pk_env_t *k)
+set_server_identity_key(crypto_pk_env_t *k)
 {
-  crypto_free_pk_env(identitykey);
-  identitykey = k;
-  crypto_pk_get_digest(identitykey, identitykey_digest);
+  crypto_free_pk_env(server_identitykey);
+  server_identitykey = k;
+  crypto_pk_get_digest(server_identitykey, server_identitykey_digest);
 }
 
-/** Returns the current identity key; requires that the identity key has been
- * set.
+/** Returns the current server identity key; requires that the key has
+ * been set.
  */
 crypto_pk_env_t *
-get_identity_key(void)
+get_server_identity_key(void)
 {
-  tor_assert(identitykey);
-  return identitykey;
+  tor_assert(server_identitykey);
+  return server_identitykey;
 }
 
-/** Return true iff the identity key has been set. */
+/** Return true iff the server identity key has been set. */
 int
-identity_key_is_set(void)
+server_identity_key_is_set(void)
 {
-  return identitykey != NULL;
+  return server_identitykey != NULL;
+}
+
+/** Set the current client identity key to <b>k</b>.
+ */
+void
+set_client_identity_key(crypto_pk_env_t *k)
+{
+  crypto_free_pk_env(client_identitykey);
+  client_identitykey = k;
+}
+
+/** Returns the current client identity key; requires that the key has
+ * been set.
+ */
+crypto_pk_env_t *
+get_client_identity_key(void)
+{
+  tor_assert(client_identitykey);
+  return client_identitykey;
+}
+
+/** Return true iff the client identity key has been set. */
+int
+client_identity_key_is_set(void)
+{
+  return client_identitykey != NULL;
 }
 
 /** Return the key certificate for this v3 (voting) authority, or NULL
@@ -470,10 +500,10 @@ init_keys(void)
       crypto_free_pk_env(prkey);
       return -1;
     }
-    set_identity_key(prkey);
+    set_client_identity_key(prkey);
     /* Create a TLS context. */
     if (tor_tls_context_init(0,
-                             get_identity_key(),
+                             get_client_identity_key(),
                              NULL,
                              MAX_SSL_KEY_LIFETIME) < 0) {
       log_err(LD_GENERAL,"Error creating TLS context for Tor client.");
@@ -510,13 +540,28 @@ init_keys(void)
     }
   }
 
-  /* 1. Read identity key. Make it if none is found. */
+  /* 1b. Read identity key. Make it if none is found. */
   keydir = get_datadir_fname2("keys", "secret_id_key");
   log_info(LD_GENERAL,"Reading/making identity key \"%s\"...",keydir);
   prkey = init_key_from_file(keydir, 1, LOG_ERR);
   tor_free(keydir);
   if (!prkey) return -1;
-  set_identity_key(prkey);
+  set_server_identity_key(prkey);
+
+  /* 1c. If we are configured as a bridge, generate a client key;
+   * otherwise, set the server identity key as our client identity
+   * key. */
+  if (public_server_mode(options)) {
+    set_client_identity_key(prkey); /* set above */
+  } else {
+    if (!(prkey = crypto_new_pk_env()))
+      return -1;
+    if (crypto_pk_generate_key(prkey)) {
+      crypto_free_pk_env(prkey);
+      return -1;
+    }
+    set_client_identity_key(prkey);
+  }
 
   /* 2. Read onion key.  Make it if none is found. */
   keydir = get_datadir_fname2("keys", "secret_onion_key");
@@ -554,8 +599,8 @@ init_keys(void)
 
   /* 3. Initialize link key and TLS context. */
   if (tor_tls_context_init(public_server_mode(options),
-                           get_identity_key(),
-                           get_identity_key(),
+                           get_client_identity_key(),
+                           get_server_identity_key(),
                            MAX_SSL_KEY_LIFETIME) < 0) {
     log_err(LD_GENERAL,"Error initializing TLS context");
     return -1;
@@ -567,7 +612,8 @@ init_keys(void)
     const char *m = NULL;
     routerinfo_t *ri;
     /* We need to add our own fingerprint so it gets recognized. */
-    if (dirserv_add_own_fingerprint(options->Nickname, get_identity_key())) {
+    if (dirserv_add_own_fingerprint(options->Nickname,
+                                    get_server_identity_key())) {
       log_err(LD_GENERAL,"Error adding own fingerprint to approved set");
       return -1;
     }
@@ -588,7 +634,8 @@ init_keys(void)
   /* 5. Dump fingerprint to 'fingerprint' */
   keydir = get_datadir_fname("fingerprint");
   log_info(LD_GENERAL,"Dumping fingerprint to \"%s\"...",keydir);
-  if (crypto_pk_get_fingerprint(get_identity_key(), fingerprint, 0)<0) {
+  if (crypto_pk_get_fingerprint(get_server_identity_key(),
+                                fingerprint, 0) < 0) {
     log_err(LD_GENERAL,"Error computing fingerprint");
     tor_free(keydir);
     return -1;
@@ -626,7 +673,7 @@ init_keys(void)
     return -1;
   }
   /* 6b. [authdirserver only] add own key to approved directories. */
-  crypto_pk_get_digest(get_identity_key(), digest);
+  crypto_pk_get_digest(get_server_identity_key(), digest);
   type = ((options->V1AuthoritativeDir ? V1_AUTHORITY : NO_AUTHORITY) |
           (options->V2AuthoritativeDir ? V2_AUTHORITY : NO_AUTHORITY) |
           (options->V3AuthoritativeDir ? V3_AUTHORITY : NO_AUTHORITY) |
@@ -1178,11 +1225,12 @@ router_my_exit_policy_is_reject_star(void)
 }
 
 /** Return true iff I'm a server and <b>digest</b> is equal to
- * my identity digest. */
+ * my server identity key digest. */
 int
 router_digest_is_me(const char *digest)
 {
-  return identitykey && !memcmp(identitykey_digest, digest, DIGEST_LEN);
+  return (server_identitykey &&
+          !memcmp(server_identitykey_digest, digest, DIGEST_LEN));
 }
 
 /** Return true iff I'm a server and <b>digest</b> is equal to
@@ -1325,7 +1373,7 @@ router_rebuild_descriptor(int force)
   ri->cache_info.published_on = time(NULL);
   ri->onion_pkey = crypto_pk_dup_key(get_onion_key()); /* must invoke from
                                                         * main thread */
-  ri->identity_pkey = crypto_pk_dup_key(get_identity_key());
+  ri->identity_pkey = crypto_pk_dup_key(get_server_identity_key());
   if (crypto_pk_get_digest(ri->identity_pkey,
                            ri->cache_info.identity_digest)<0) {
     routerinfo_free(ri);
@@ -1420,7 +1468,8 @@ router_rebuild_descriptor(int force)
   ei_size = options->ExtraInfoStatistics ? MAX_EXTRAINFO_UPLOAD_SIZE : 8192;
   ei->cache_info.signed_descriptor_body = tor_malloc(ei_size);
   if (extrainfo_dump_to_string(ei->cache_info.signed_descriptor_body,
-                               ei_size, ei, get_identity_key()) < 0) {
+                               ei_size, ei,
+                               get_server_identity_key()) < 0) {
     log_warn(LD_BUG, "Couldn't generate extra-info descriptor.");
     routerinfo_free(ri);
     extrainfo_free(ei);
@@ -1437,7 +1486,7 @@ router_rebuild_descriptor(int force)
          DIGEST_LEN);
   ri->cache_info.signed_descriptor_body = tor_malloc(8192);
   if (router_dump_router_to_string(ri->cache_info.signed_descriptor_body, 8192,
-                                   ri, get_identity_key())<0) {
+                                   ri, get_server_identity_key()) < 0) {
     log_warn(LD_BUG, "Couldn't generate router descriptor.");
     routerinfo_free(ri);
     extrainfo_free(ei);
@@ -2186,7 +2235,8 @@ router_free_all(void)
 {
   crypto_free_pk_env(onionkey);
   crypto_free_pk_env(lastonionkey);
-  crypto_free_pk_env(identitykey);
+  crypto_free_pk_env(server_identitykey);
+  crypto_free_pk_env(client_identitykey);
   tor_mutex_free(key_lock);
   routerinfo_free(desc_routerinfo);
   extrainfo_free(desc_extrainfo);