From 235b15a590eecf97b09e87bdb7e4f8333e9de129 Mon Sep 17 00:00:00 2001
From: Nick Wellnhofer <[email protected]>
Date: Mon, 8 May 2023 17:58:02 +0200
Subject: [PATCH] SAX: Always initialize SAX1 element handlers

Follow-up to commit d0c3f01e. A parser context will be initialized to
SAX version 2, but this can be overridden with XML_PARSE_SAX1 later,
so we must initialize the SAX1 element handlers as well.

Change the check in xmlDetectSAX2 to only look for XML_SAX2_MAGIC, so
we don't switch to SAX1 if the SAX2 element handlers are NULL.
---
 SAX2.c   | 11 +++++++----
 parser.c |  5 +----
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/SAX2.c b/SAX2.c
index b6be1a6c4..910193892 100644
--- a/SAX2.c
+++ b/SAX2.c
@@ -2874,20 +2874,23 @@ xmlSAXVersion(xmlSAXHandler *hdlr, int version)
 {
     if (hdlr == NULL) return(-1);
     if (version == 2) {
-	hdlr->startElement = NULL;
-	hdlr->endElement = NULL;
 	hdlr->startElementNs = xmlSAX2StartElementNs;
 	hdlr->endElementNs = xmlSAX2EndElementNs;
 	hdlr->serror = NULL;
 	hdlr->initialized = XML_SAX2_MAGIC;
 #ifdef LIBXML_SAX1_ENABLED
     } else if (version == 1) {
-	hdlr->startElement = xmlSAX2StartElement;
-	hdlr->endElement = xmlSAX2EndElement;
 	hdlr->initialized = 1;
 #endif /* LIBXML_SAX1_ENABLED */
     } else
         return(-1);
+#ifdef LIBXML_SAX1_ENABLED
+    hdlr->startElement = xmlSAX2StartElement;
+    hdlr->endElement = xmlSAX2EndElement;
+#else
+    hdlr->startElement = NULL;
+    hdlr->endElement = NULL;
+#endif /* LIBXML_SAX1_ENABLED */
     hdlr->internalSubset = xmlSAX2InternalSubset;
     hdlr->externalSubset = xmlSAX2ExternalSubset;
     hdlr->isStandalone = xmlSAX2IsStandalone;
diff --git a/parser.c b/parser.c
index 0c8bed129..e133fe0a6 100644
--- a/parser.c
+++ b/parser.c
@@ -842,10 +842,7 @@ xmlDetectSAX2(xmlParserCtxtPtr ctxt) {
     if (ctxt == NULL) return;
     sax = ctxt->sax;
 #ifdef LIBXML_SAX1_ENABLED
-    if ((sax) &&  (sax->initialized == XML_SAX2_MAGIC) &&
-        ((sax->startElementNs != NULL) ||
-         (sax->endElementNs != NULL) ||
-         ((sax->startElement == NULL) && (sax->endElement == NULL))))
+    if ((sax) && (sax->initialized == XML_SAX2_MAGIC))
         ctxt->sax2 = 1;
 #else
     ctxt->sax2 = 1;
-- 
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