bugfix: fixed one potential memory leak in an error condition.

Signed-off-by: Yichun Zhang (agentzh) <[email protected]>

Author: dyu

src/ngx_http_encrypted_session_cipher.c

@@ -98,14 +98,15 @@ ngx_http_encrypted_session_aes_mac_encrypt(ngx_pool_t *pool, ngx_log_t *log,
     p += len;
 
     ret = EVP_EncryptFinal(&ctx, p, &len);
-    if (!ret) {
-        return NGX_ERROR;
-    }
 
     /* XXX we should still explicitly release the ctx
      * or we'll leak memory here */
     EVP_CIPHER_CTX_cleanup(&ctx);
 
+    if (!ret) {
+        return NGX_ERROR;
+    }
+
     p += len;
 
     *dst_len = p - *dst;