From a781ee3395ad715c6383842463d412591a63e117 Mon Sep 17 00:00:00 2001
From: Nick Wellnhofer <wellnhofer@aevum.de>
Date: Mon, 21 Nov 2022 20:10:42 +0100
Subject: [PATCH] Revert "parser: Add overflow checks to xmlParseLookup
 functions"

This reverts commit bfc55d688427972d093be010a8c2ef265375fcb2.

It's better to fix the root cause.
---
 parser.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/parser.c b/parser.c
index 3b64c434..cc82b6e3 100644
--- a/parser.c
+++ b/parser.c
@@ -11083,17 +11083,14 @@ xmlParseExtParsedEnt(xmlParserCtxtPtr ctxt) {
 static int
 xmlParseLookupChar(xmlParserCtxtPtr ctxt, int c) {
     const xmlChar *cur;
-    const xmlChar *end = ctxt->input->end;
 
     if (ctxt->checkIndex == 0) {
         cur = ctxt->input->cur + 1;
     } else {
         cur = ctxt->input->cur + ctxt->checkIndex;
     }
-    if (cur >= end)
-        return(0);
 
-    if (memchr(cur, c, end - cur) == NULL) {
+    if (memchr(cur, c, ctxt->input->end - cur) == NULL) {
         ctxt->checkIndex = ctxt->input->end - ctxt->input->cur;
         return(0);
     } else {
@@ -11115,18 +11112,17 @@ static const xmlChar *
 xmlParseLookupString(xmlParserCtxtPtr ctxt, size_t startDelta,
                      const char *str, size_t strLen) {
     const xmlChar *cur, *term;
-    const xmlChar *end = ctxt->input->end;
 
     if (ctxt->checkIndex == 0) {
         cur = ctxt->input->cur + startDelta;
     } else {
         cur = ctxt->input->cur + ctxt->checkIndex;
     }
-    if (cur >= end)
-        return(0);
 
     term = BAD_CAST strstr((const char *) cur, str);
     if (term == NULL) {
+        const xmlChar *end = ctxt->input->end;
+
         /* Rescan (strLen - 1) characters. */
         if ((size_t) (end - cur) < strLen)
             end = cur;