Merge remote-tracking branch 'public/bug19152_024_v2' into maint-0.2.4

changes/rsa_init_bug

@@ -0,0 +1,7 @@
+  o Major bugfixes (key management):
+    - If OpenSSL fails to generate an RSA key, do not retain a dangling pointer
+      to the previous (uninitialized) key value. The impact here should be
+      limited to a difficult-to-trigger crash, if OpenSSL is running an
+      engine that makes key generation failures possible, or if OpenSSL runs
+      out of memory. Fixes bug 19152; bugfix on 0.2.1.10-alpha. Found by
+      Yuan Jochen Kang, Suman Jana, and Baishakhi Ray.

src/common/crypto.c

@@ -466,8 +466,10 @@ crypto_pk_generate_key_with_bits(crypto_pk_t *env, int bits)
 {
   tor_assert(env);
 
-  if (env->key)
+  if (env->key) {
     RSA_free(env->key);
+    env->key = NULL;
+  }
 
   {
     BIGNUM *e = BN_new();