Disallow conditional sections in internal subset

Conditional sections are only allowed in *external* parameter entities
referenced from the internal subset.

parser.c

@@ -8300,10 +8300,10 @@ xmlParseInternalSubset(xmlParserCtxtPtr ctxt) {
 	    xmlParsePEReference(ctxt);
 
             /*
-             * Conditional sections are allowed from entities included
+             * Conditional sections are allowed from external entities included
              * by PE References in the internal subset.
              */
-            if ((ctxt->inputNr > 1) &&
+            if ((ctxt->inputNr > 1) && (ctxt->input->filename != NULL) &&
                 (RAW == '<') && (NXT(1) == '!') && (NXT(2) == '[')) {
                 xmlParseConditionalSections(ctxt);
             }

result/errors/759573-2.xml.err

@@ -16,33 +16,20 @@ Entity: line 1: parser error : ParsePI: PI xDOCTYPEm space expected
 Entity: line 1: 
 <!ENTITY<?xDOCTYPEm~?>
                    ^
-Entity: line 3: parser error : Space required after '<!ENTITY'
-%zz;<!ELEMENTD(%MENT%MENTDŹMENTD%zNMT9KENSMYSYSTEM;MENT9%zz;
-    ^
-Entity: line 1: 
-<!ENTITY<?xDOCTYPEm~?>
-        ^
-Entity: line 3: parser error : xmlParseEntityDecl: no name
-%zz;<!ELEMENTD(%MENT%MENTDŹMENTD%zNMT9KENSMYSYSTEM;MENT9%zz;
+./test/errors/759573-2.xml:6: parser error : internal error: xmlParseInternalSubset: error detected in Markup declaration
+
+%xx;ggKENSMYNT&#35;MENTD&#372zz;'>
     ^
-Entity: line 1: 
-<!ENTITY<?xDOCTYPEm~?>
-        ^
-Entity: line 3: parser error : ParsePI: PI xDOCTYPEm space expected
-%zz;<!ELEMENTD(%MENT%MENTDŹMENTD%zNMT9KENSMYSYSTEM;MENT9%zz;
+Entity: line 2: 
+<![INCLUDE[
+^
+./test/errors/759573-2.xml:6: parser error : internal error: xmlParseInternalSubset: error detected in Markup declaration
+
+%xx;ggKENSMYNT&#35;MENTD&#372zz;'>
     ^
-Entity: line 1: 
-<!ENTITY<?xDOCTYPEm~?>
-                   ^
-./test/errors/759573-2.xml:6: parser error : Space required after 'ELEMENT'
+./test/errors/759573-2.xml:6: parser error : DOCTYPE improperly terminated
 %xx;ggKENSMYNT&#35;MENTD&#372zz;'>
     ^
-Entity: line 3: 
-%zz;<!ELEMENTD(%MENT%MENTDŹMENTD%zNMT9KENSMYSYSTEM;MENT9%zz;
-             ^
-./test/errors/759573-2.xml:6: parser error : Content error in the external subset
+./test/errors/759573-2.xml:6: parser error : Start tag expected, '<' not found
 %xx;ggKENSMYNT&#35;MENTD&#372zz;'>
     ^
-Entity: line 3: 
-%zz;<!ELEMENTD(%MENT%MENTDŹMENTD%zNMT9KENSMYSYSTEM;MENT9%zz;
-             ^

result/errors/759573.xml.err

@@ -13,9 +13,20 @@ T t (A)><!ENTITY % xx '&#37;<![INCLUDE[000&#37;&#3000;000&#37;z;'><!ENTITYz>%xx;
 Entity: line 1: 
 %<![INCLUDE[000%ஸ000%z;
  ^
-./test/errors/759573.xml:1: parser error : Content error in the external subset
+./test/errors/759573.xml:1: parser error : internal error: xmlParseInternalSubset: error detected in Markup declaration
+
 T t (A)><!ENTITY % xx '&#37;<![INCLUDE[000&#37;&#3000;000&#37;z;'><!ENTITYz>%xx;
                                                                                ^
 Entity: line 1: 
 %<![INCLUDE[000%ஸ000%z;
-            ^
+ ^
+./test/errors/759573.xml:1: parser error : internal error: xmlParseInternalSubset: error detected in Markup declaration
+
+T t (A)><!ENTITY % xx '&#37;<![INCLUDE[000&#37;&#3000;000&#37;z;'><!ENTITYz>%xx;
+                                                                               ^
+./test/errors/759573.xml:1: parser error : DOCTYPE improperly terminated
+T t (A)><!ENTITY % xx '&#37;<![INCLUDE[000&#37;&#3000;000&#37;z;'><!ENTITYz>%xx;
+                                                                               ^
+./test/errors/759573.xml:1: parser error : Start tag expected, '<' not found
+T t (A)><!ENTITY % xx '&#37;<![INCLUDE[000&#37;&#3000;000&#37;z;'><!ENTITYz>%xx;
+                                                                               ^