From 3b4245db2e954675d15f50a0e9d004e62a43a48c Mon Sep 17 00:00:00 2001
From: Tomas Popela <tpopela@redhat.com>
Date: Mon, 23 Jul 2018 09:50:53 +0200
Subject: [PATCH 02/17] Check whether document has a root element before
 accessing it.

yelp-3.28.1/libyelp/yelp-docbook-document.c:562:13: note: Access to field 'ns' results in a dereference of a null pointer (loaded from field 'xmlcur')
        if (priv->xmlcur->ns) {
            ^     ~~~~~~
  560|            * unique value, and insert it into the in-memory tree */
  561|           g_snprintf (autoidstr, 20, "//autoid-%d", ++autoid);
  562|->         if (priv->xmlcur->ns) {
  563|               xmlNewNsProp (priv->xmlcur,
  564|                             xmlNewNs (priv->xmlcur, XML_XML_NAMESPACE, BAD_CAST "xml"),

yelp-3.28.1/libyelp/yelp-docbook-document.c:608:16: note: Access to field 'children' results in a dereference of a null pointer (loaded from field 'xmlcur')
    for (cur = priv->xmlcur->children; cur; cur = cur->next) {
               ^     ~~~~~~
  606|                                 NULL);
  607|
  608|->     for (cur = priv->xmlcur->children; cur; cur = cur->next) {
  609|           if (cur->type == XML_ELEMENT_NODE) {
  610|               priv->xmlcur = cur;
---
 libyelp/yelp-docbook-document.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/libyelp/yelp-docbook-document.c b/libyelp/yelp-docbook-document.c
index 6ecaf316..24746248 100644
--- a/libyelp/yelp-docbook-document.c
+++ b/libyelp/yelp-docbook-document.c
@@ -309,6 +309,7 @@ docbook_process (YelpDocbookDocument *docbook)
     GFile *file = NULL;
     gchar *filepath = NULL;
     xmlDocPtr xmldoc = NULL;
+    xmlNodePtr xmlcur = NULL;
     xmlChar *id = NULL;
     xmlParserCtxtPtr parserCtxt = NULL;
     GError *error;
@@ -343,7 +344,10 @@ docbook_process (YelpDocbookDocument *docbook)
                               XML_PARSE_DTDLOAD | XML_PARSE_NOCDATA |
                               XML_PARSE_NOENT   | XML_PARSE_NONET   );
 
-    if (xmldoc == NULL) {
+    if (xmldoc)
+        xmlcur = xmlDocGetRootElement (xmldoc);
+
+    if (xmldoc == NULL || xmlcur == NULL) {
         error = g_error_new (YELP_ERROR, YELP_ERROR_PROCESSING,
                              _("The file ‘%s’ could not be parsed because it is"
                                " not a well-formed XML document."),
@@ -374,7 +378,7 @@ docbook_process (YelpDocbookDocument *docbook)
         priv->max_depth = 1;
 
     priv->xmldoc = xmldoc;
-    priv->xmlcur = xmlDocGetRootElement (xmldoc);
+    priv->xmlcur = xmlcur;
 
     id = xmlGetProp (priv->xmlcur, BAD_CAST "id");
     if (!id)
-- 
2.19.1