Backport: Fix bug 889: share deep-copied keys between threads to avoid races in reference counts. Bugfix on 0.1.0.1-rc.

svn:r17674

ChangeLog

@@ -46,6 +46,9 @@ Changes in version 0.2.0.33 - 200?-??-??
     - Fix a memory leak when we decline to add a v2 rendezvous descriptor to
       the cache because we already had a v0 descriptor with the same ID.
       Bugfix on 0.2.0.18-alpha.
+    - Fix a race condition when freeing keys shared between main thread
+      and CPU workers that could result in a memory leak.  Bugfix on
+      0.1.0.1-rc.  Fixes bug 889.
 
   o Minor features:
     - Report the case where all signatures in a detached set are rejected

src/common/crypto.c

@@ -631,6 +631,23 @@ crypto_pk_dup_key(crypto_pk_env_t *env)
   return env;
 }
 
+/** Make a real honest-to-goodness copy of <b>env</b>, and return it. */
+crypto_pk_env_t *
+crypto_pk_copy_full(crypto_pk_env_t *env)
+{
+  RSA *new_key;
+  tor_assert(env);
+  tor_assert(env->key);
+
+  if (PRIVATE_KEY_OK(env)) {
+    new_key = RSAPrivateKey_dup(env->key);
+  } else {
+    new_key = RSAPublicKey_dup(env->key);
+  }
+
+  return _crypto_new_pk_env_rsa(new_key);
+}
+
 /** Encrypt <b>fromlen</b> bytes from <b>from</b> with the public key
  * in <b>env</b>, using the padding method <b>padding</b>.  On success,
  * write the result to <b>to</b>, and return the number of bytes

src/common/crypto.h

@@ -88,6 +88,7 @@ int crypto_pk_check_key(crypto_pk_env_t *env);
 int crypto_pk_cmp_keys(crypto_pk_env_t *a, crypto_pk_env_t *b);
 size_t crypto_pk_keysize(crypto_pk_env_t *env);
 crypto_pk_env_t *crypto_pk_dup_key(crypto_pk_env_t *orig);
+crypto_pk_env_t *crypto_pk_copy_full(crypto_pk_env_t *orig);
 
 int crypto_pk_public_encrypt(crypto_pk_env_t *env, char *to,
                              const char *from, size_t fromlen, int padding);

src/or/router.c

@@ -75,8 +75,8 @@ get_onion_key(void)
   return onionkey;
 }
 
-/** Store a copy of the current onion key into *<b>key</b>, and a copy
- * of the most recent onion key into *<b>last</b>.
+/** Store a full copy of the current onion key into *<b>key</b>, and a full
+ * copy of the most recent onion key into *<b>last</b>.
  */
 void
 dup_onion_keys(crypto_pk_env_t **key, crypto_pk_env_t **last)
@@ -85,9 +85,9 @@ dup_onion_keys(crypto_pk_env_t **key, crypto_pk_env_t **last)
   tor_assert(last);
   tor_mutex_acquire(key_lock);
   tor_assert(onionkey);
-  *key = crypto_pk_dup_key(onionkey);
+  *key = crypto_pk_copy_full(onionkey);
   if (lastonionkey)
-    *last = crypto_pk_dup_key(lastonionkey);
+    *last = crypto_pk_copy_full(lastonionkey);
   else
     *last = NULL;
   tor_mutex_release(key_lock);