Heap-based buffer-underreads due to xmlParseName

For https://bugzilla.gnome.org/show_bug.cgi?id=759573

* parser.c:
(xmlParseElementDecl): Return early on invalid input to fix
non-minimized test case (759573-2.xml).  Otherwise the parser
gets into a bad state in SKIP(3) at the end of the function.
(xmlParseConditionalSections): Halt parsing when hitting invalid
input that would otherwise caused xmlParserHandlePEReference()
to recurse unexpectedly.  This fixes the minimized test case
(759573.xml).

* result/errors/759573-2.xml: Add.
* result/errors/759573-2.xml.err: Add.
* result/errors/759573-2.xml.str: Add.
* result/errors/759573.xml: Add.
* result/errors/759573.xml.err: Add.
* result/errors/759573.xml.str: Add.
* test/errors/759573-2.xml: Add.
* test/errors/759573.xml: Add.

1 files changed, 2 insertions, 0 deletions

diff --git a/parser.c b/parser.c
index 7aba6a9b..ea0e89ea 100644
--- a/parser.c
+++ b/parser.c
@@ -6708,6 +6708,7 @@ xmlParseElementDecl(xmlParserCtxtPtr ctxt) {
 	if (!IS_BLANK_CH(CUR)) {
 	    xmlFatalErrMsg(ctxt, XML_ERR_SPACE_REQUIRED,
 		           "Space required after 'ELEMENT'\n");
+	    return(-1);
 	}
         SKIP_BLANKS;
         name = xmlParseName(ctxt);
@@ -6859,6 +6860,7 @@ xmlParseConditionalSections(xmlParserCtxtPtr ctxt) {
 
 	    if ((CUR_PTR == check) && (cons == ctxt->input->consumed)) {
 		xmlFatalErr(ctxt, XML_ERR_EXT_SUBSET_NOT_FINISHED, NULL);
+		xmlHaltParser(ctxt);
 		break;
 	    }
 	}