commit 835df27bc1a1eae1ec51b14122ea40c974dd7409
Author: Tomas Korbar <tkorbar@redhat.com>
Date:   Mon Feb 14 12:29:20 2022 +0100

    CVE-2021-46143

diff --git a/lib/xmlparse.c b/lib/xmlparse.c
index c45be0c..22d0a75 100644
--- a/lib/xmlparse.c
+++ b/lib/xmlparse.c
@@ -4995,6 +4995,11 @@ doProlog(XML_Parser parser, const ENCODING *enc, const char *s, const char *end,
     case XML_ROLE_GROUP_OPEN:
       if (parser->m_prologState.level >= parser->m_groupSize) {
         if (parser->m_groupSize) {
+          /* Detect and prevent integer overflow */
+          if (parser->m_groupSize > (unsigned int)(-1) / 2u) {
+            return XML_ERROR_NO_MEMORY;
+          }
+
           char *temp = (char *)REALLOC(parser, parser->m_groupConnector, parser->m_groupSize *= 2);
           if (temp == NULL) {
             parser->m_groupSize /= 2;
@@ -5002,6 +5007,15 @@ doProlog(XML_Parser parser, const ENCODING *enc, const char *s, const char *end,
           }
           parser->m_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 (parser->m_groupSize > (size_t)(-1) / sizeof(int)) {
+              return XML_ERROR_NO_MEMORY;
+            }
+#endif
             int *temp = (int *)REALLOC(parser, dtd->scaffIndex,
                           parser->m_groupSize * sizeof(int));
             if (temp == NULL)