[libxml2] Disallow conditional sections in internal subset

[Nick Wellnhofer <nwellnhof src gnome org>]

commit c2f209c09f383ccfaa2bf8fe9b63882366bf4aec
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Mon Sep 30 14:13:21 2019 +0200

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

 parser.c                       |  4 ++--
 result/errors/759573-2.xml.err | 35 +++++++++++------------------------
 result/errors/759573.xml.err   | 15 +++++++++++++--
 3 files changed, 26 insertions(+), 28 deletions(-)
---
diff --git a/parser.c b/parser.c
index 20297005..4e98a9a8 100644
--- a/parser.c
+++ b/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);
             }
diff --git a/result/errors/759573-2.xml.err b/result/errors/759573-2.xml.err
index ecaf18fc..4c454758 100644
--- a/result/errors/759573-2.xml.err
+++ b/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;
-             ^
diff --git a/result/errors/759573.xml.err b/result/errors/759573.xml.err
index 2617cad3..55247503 100644
--- a/result/errors/759573.xml.err
+++ b/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;
+                                                                               ^