commit d6a09f1b7fb24dd03dc58e45062ad951a37ff8e3
author Sadaf Ebrahimi <sadafebrahimi@google.com> Thu Jun 02 19:32:22 2022 +0000
committer Sadaf Ebrahimi <sadafebrahimi@google.com> Thu Jun 02 19:35:38 2022 +0000
tree 9292171eaaf4990f24e84d787a7416b99f094674
parent 3c8c2304206e5e6f917b3919bea9d10ea37830a0

Prevent XML_GetBuffer signed integer overflow

Bug: http://b/221255869
Change-Id: I38758fae8c71184f728f95e6073457cdb86bcc29

lib/xmlparse.c

diff --git a/lib/xmlparse.c b/lib/xmlparse.c
index c4f3ffc..ca29328 100644
--- a/lib/xmlparse.c
+++ b/lib/xmlparse.c
@@ -2047,6 +2047,11 @@
     keep = (int)EXPAT_SAFE_PTR_DIFF(parser->m_bufferPtr, parser->m_buffer);
     if (keep > XML_CONTEXT_BYTES)
       keep = XML_CONTEXT_BYTES;
+    /* Detect and prevent integer overflow */
+    if (keep > INT_MAX - neededSize) {
+      parser->m_errorCode = XML_ERROR_NO_MEMORY;
+      return NULL;
+    }
     neededSize += keep;
 #endif  /* defined XML_CONTEXT_BYTES */
     if (neededSize <= EXPAT_SAFE_PTR_DIFF(parser->m_bufferLim, parser->m_buffer)) {