[PATCH] xmlschemastypes.c: xmlSchemaGetFacetValueAsULong add, check "facet->val"

The xmlSchemaGetFacetValueAsUlong() API is an external API.
The validity of external input parameters must be strictly verified.
Before accessing "facet->val->value", we need check whether "facet->val" is
a null pointer.

Signed-off-by: wuqing <[email protected]>
Signed-off-by: Xiaoming Ni <[email protected]>
---
  xmlschemastypes.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xmlschemastypes.c b/xmlschemastypes.c
index d6b9f924..07b5fd76 100644
--- a/xmlschemastypes.c
+++ b/xmlschemastypes.c
@@ -5142,7 +5142,7 @@ xmlSchemaGetFacetValueAsULong(xmlSchemaFacetPtr facet)
      /*
      * TODO: Check if this is a decimal.
      */
-    if (facet == NULL)
+    if (facet == NULL || facet->val == NULL)
          return 0;
      return ((unsigned long) facet->val->value.decimal.lo);
  }
-- 
2.27.0