commit 25f4e86a2b3e8d1e12c4fcd6ba0ef182e2d0a387

Author: Tomas Korbar <tkorbar@redhat.com>

Date:   Mon Feb 21 16:55:36 2022 +0100

    CVE-2021-45960

diff --git a/lib/xmlparse.c b/lib/xmlparse.c

index d4f30b7..e743f78 100644

--- a/lib/xmlparse.c

+++ b/lib/xmlparse.c

@@ -2922,7 +2922,13 @@ storeAtts(XML_Parser parser, const ENCODING *enc,

   if (nPrefixes) {

     int j;  /* hash table index */

     unsigned long version = nsAttsVersion;

-    int nsAttsSize = (int)1 << nsAttsPower;

+    /* Detect and prevent invalid shift */

+    if (parser->m_nsAttsPower >= sizeof(unsigned int) * 8 /* bits per byte */) {

+      return XML_ERROR_NO_MEMORY;

+    }

+

+    unsigned int nsAttsSize = 1u << parser->m_nsAttsPower;

+    unsigned char oldNsAttsPower = parser->m_nsAttsPower;

     /* size of hash table must be at least 2 * (# of prefixed attributes) */

     if ((nPrefixes << 1) >> nsAttsPower) {  /* true for nsAttsPower = 0 */

       NS_ATT *temp;

@@ -2930,10 +2936,34 @@ storeAtts(XML_Parser parser, const ENCODING *enc,

       while (nPrefixes >> nsAttsPower++);

       if (nsAttsPower < 3)

         nsAttsPower = 3;

-      nsAttsSize = (int)1 << nsAttsPower;

+

+      /* Detect and prevent invalid shift */

+      if (parser->m_nsAttsPower >= sizeof(nsAttsSize) * 8 /* bits per byte */) {

+        /* Restore actual size of memory in m_nsAtts */

+        parser->m_nsAttsPower = oldNsAttsPower;

+        return XML_ERROR_NO_MEMORY;

+      }

+

+      nsAttsSize = 1u << parser->m_nsAttsPower;

+

+      /* 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 (nsAttsSize > (size_t)(-1) / sizeof(NS_ATT)) {

+        /* Restore actual size of memory in m_nsAtts */

+        parser->m_nsAttsPower = oldNsAttsPower;

+        return XML_ERROR_NO_MEMORY;

+      }

+#endif

+

       temp = (NS_ATT *)REALLOC(nsAtts, nsAttsSize * sizeof(NS_ATT));

-      if (!temp)

+      if (!temp) {

+        /* Restore actual size of memory in m_nsAtts */

+        parser->m_nsAttsPower = oldNsAttsPower;

         return XML_ERROR_NO_MEMORY;

+      }

       nsAtts = temp;

       version = 0;  /* force re-initialization of nsAtts hash table */

     }