From c20b758c332d9a13afbbb276d30db1d183a85d43 Mon Sep 17 00:00:00 2001
From: Sebastian Pipping <[email protected]>
Date: Wed, 28 Aug 2019 00:24:59 +0200
Subject: [PATCH 189/286] xmlparse.c: Deny internal entities closing the
 doctype

---
 expat/lib/xmlparse.c | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/lib/xmlparse.c b/lib/xmlparse.c
index f4506b0..3df4347 100644
--- a/lib/xmlparse.c
+++ b/lib/xmlparse.c
@@ -412,9 +412,10 @@ processXmlDecl(XML_Parser parser, int isGeneralTextEntity,
 static enum XML_Error
 initializeEncoding(XML_Parser parser);
 static enum XML_Error
-doProlog(XML_Parser parser, const ENCODING *enc, const char *s,
-         const char *end, int tok, const char *next, const char **nextPtr,
-         XML_Bool haveMore);
+doProlog(XML_Parser parser, const ENCODING *enc,
+         const char *s, const char *end, int tok,
+         const char *next, const char **nextPtr,
+         XML_Bool haveMore, XML_Bool allowClosingDoctype);
 static enum XML_Error
 processInternalEntity(XML_Parser parser, ENTITY *entity,
                       XML_Bool betweenDecl);
@@ -4240,8 +4241,8 @@ externalParEntProcessor(XML_Parser parser,
   }
 
   parser->m_processor = prologProcessor;
-  return doProlog(parser, parser->m_encoding, s, end, tok, next,
-                  nextPtr, (XML_Bool)!parser->m_parsingStatus.finalBuffer);
+  return doProlog(parser, parser->m_encoding, s, end, tok, next, nextPtr,
+                  (XML_Bool)!parser->m_parsingStatus.finalBuffer, XML_TRUE);
 }
 
 static enum XML_Error PTRCALL
@@ -4290,20 +4291,14 @@ prologProcessor(XML_Parser parser,
 {
   const char *next = s;
   int tok = XmlPrologTok(parser->m_encoding, s, end, &next);
-  return doProlog(parser, parser->m_encoding, s, end, tok, next,
-                  nextPtr, (XML_Bool)!parser->m_parsingStatus.finalBuffer);
+  return doProlog(parser, parser->m_encoding, s, end, tok, next, nextPtr,
+                  (XML_Bool)!parser->m_parsingStatus.finalBuffer, XML_TRUE);
 }
 
 static enum XML_Error
-doProlog(XML_Parser parser,
-         const ENCODING *enc,
-         const char *s,
-         const char *end,
-         int tok,
-         const char *next,
-         const char **nextPtr,
-         XML_Bool haveMore)
-{
+doProlog(XML_Parser parser, const ENCODING *enc, const char *s, const char *end,
+         int tok, const char *next, const char **nextPtr, XML_Bool haveMore,
+         XML_Bool allowClosingDoctype) {
 #ifdef XML_DTD
   static const XML_Char externalSubsetName[] = { ASCII_HASH , '\0' };
 #endif /* XML_DTD */
@@ -4481,6 +4476,11 @@ doProlog(XML_Parser parser,
       }
       break;
     case XML_ROLE_DOCTYPE_CLOSE:
+      if (allowClosingDoctype != XML_TRUE) {
+        /* Must not close doctype from within expanded parameter entities */
+        return XML_ERROR_INVALID_TOKEN;
+      }
+
       if (parser->m_doctypeName) {
         parser->m_startDoctypeDeclHandler(parser->m_handlerArg, parser->m_doctypeName,
                                 parser->m_doctypeSysid, parser->m_doctypePubid, 0);
@@ -5417,8 +5417,8 @@ processInternalEntity(XML_Parser parser, ENTITY *entity,
 #ifdef XML_DTD
   if (entity->is_param) {
     int tok = XmlPrologTok(parser->m_internalEncoding, textStart, textEnd, &next);
-    result = doProlog(parser, parser->m_internalEncoding, textStart, textEnd, tok,
-                      next, &next, XML_FALSE);
+    result = doProlog(parser, parser->m_internalEncoding, textStart, textEnd,
+                      tok, next, &next, XML_FALSE, XML_FALSE);
   }
   else
 #endif /* XML_DTD */
@@ -5464,8 +5464,8 @@ internalEntityProcessor(XML_Parser parser,
 #ifdef XML_DTD
   if (entity->is_param) {
     int tok = XmlPrologTok(parser->m_internalEncoding, textStart, textEnd, &next);
-    result = doProlog(parser, parser->m_internalEncoding, textStart, textEnd, tok,
-                      next, &next, XML_FALSE);
+    result = doProlog(parser, parser->m_internalEncoding, textStart, textEnd,
+                      tok, next, &next, XML_FALSE, XML_TRUE);
   }
   else
 #endif /* XML_DTD */
@@ -5492,7 +5492,7 @@ internalEntityProcessor(XML_Parser parser,
     parser->m_processor = prologProcessor;
     tok = XmlPrologTok(parser->m_encoding, s, end, &next);
     return doProlog(parser, parser->m_encoding, s, end, tok, next, nextPtr,
-                    (XML_Bool)!parser->m_parsingStatus.finalBuffer);
+                    (XML_Bool)!parser->m_parsingStatus.finalBuffer, XML_TRUE);
   }
   else
 #endif /* XML_DTD */
---
2.19.1