File expat-CVE-2021-46143.patch of Package expat.26154

From 85ae9a2d7d0e9358f356b33977b842df8ebaec2b Mon Sep 17 00:00:00 2001
From: Sebastian Pipping <sebastian@pipping.org>
Date: Sat, 25 Dec 2021 20:52:08 +0100
Subject: [PATCH] lib: Prevent integer overflow on m_groupSize in function
 doProlog (CVE-2021-46143)

---
 expat/lib/xmlparse.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

Index: expat-2.1.0/lib/xmlparse.c
===================================================================
--- expat-2.1.0.orig/lib/xmlparse.c
+++ expat-2.1.0/lib/xmlparse.c
@@ -4517,11 +4517,31 @@ doProlog(XML_Parser parser,
     case XML_ROLE_GROUP_OPEN:
       if (prologState.level >= groupSize) {
         if (groupSize) {
-          char *temp = (char *)REALLOC(groupConnector, groupSize *= 2);
-          if (temp == NULL)
-            return XML_ERROR_NO_MEMORY;
-          groupConnector = temp;
+          {
+            /* Detect and prevent integer overflow */
+            if (groupSize > (unsigned int)(-1) / 2u) {
+              return XML_ERROR_NO_MEMORY;
+            }
+            
+            char *temp = (char *)REALLOC(groupConnector, groupSize *= 2);
+            if (temp == NULL) {
+              groupSize /= 2;
+              return XML_ERROR_NO_MEMORY;
+            }
+            groupConnector = temp;
+          }
+
           if (dtd->scaffIndex) {
+            /* Detect and prevent integer overflow.
+             * The preprocessor guard addresses the "always false" warning
+             * from -Wtype-limits on platforms where
+             * sizeof(unsigned int) < sizeof(size_t), e.g. on x86_64. */
+#if UINT_MAX >= SIZE_MAX
+            if (groupSize > (size_t)(-1) / sizeof(int)) {
+              return XML_ERROR_NO_MEMORY;
+            }
+#endif
+
             int *temp = (int *)REALLOC(dtd->scaffIndex,
                           groupSize * sizeof(int));
             if (temp == NULL)