[xml] [PATCH] encoding: fix memleak in xmlRegisterCharEncodingHandler()

[Xiaoming Ni <nixiaoming huawei com>]

The return type of xmlRegisterCharEncodingHandler() is void. The invoker
cannot determine whether xmlRegisterCharEncodingHandler() is executed
successfully. when nbCharEncodingHandler >= MAX_ENCODING_HANDLERS, the
"handler" is not added to the array "handlers". As a result, the memory
of "handler" cannot be managed and released: memory leakage.

so add "xmlfree(handler)" to fix memory leakage on the failure branch of
xmlRegisterCharEncodingHandler().

Reported-by: wuqing <wuqing30 huawei com>
Signed-off-by: Xiaoming Ni <nixiaoming huawei com>
---
 encoding.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/encoding.c b/encoding.c
index c34aca44..841540ed 100644
--- a/encoding.c
+++ b/encoding.c
@@ -1488,16 +1488,25 @@ 
xmlRegisterCharEncodingHandler(xmlCharEncodingHandlerPtr handler) {
     if ((handler == NULL) || (handlers == NULL)) {
         xmlEncodingErr(XML_I18N_NO_HANDLER,
                "xmlRegisterCharEncodingHandler: NULL handler !\n", NULL);
-       return;
+        goto free_handler;
     }

     if (nbCharEncodingHandler >= MAX_ENCODING_HANDLERS) {
         xmlEncodingErr(XML_I18N_EXCESS_HANDLER,
        "xmlRegisterCharEncodingHandler: Too many handler registered, see %s\n",
                       "MAX_ENCODING_HANDLERS");
-       return;
+        goto free_handler;
     }
     handlers[nbCharEncodingHandler++] = handler;
+    return;
+
+free_handler:
+    if (handler != NULL) {
+        if (handler->name != NULL) {
+            xmlFree(handler->name);
+        }
+        xmlFree(handler);
+    }
 }

 /**
--
2.27.0