Buffer overrun in dlls/riched20/editor.c

[Juan Lang]

Hi Dylan, commit 11c80396995065701205f2facb3dba10a6f8170f[1]
introduced a buffer overrun in riched20's editor.c.  Here's the hunk
that did it:

@@ -666,35 +661,83 @@ static void ME_RTFParAttrHook(RTF_Info *info)

 static void ME_RTFTblAttrHook(RTF_Info *info)
 {
-  ME_DisplayItem *para;
-
   switch (info->rtfMinor)
   {
     case rtfRowDef:
-      RTFFlushOutputBuffer(info);
-      para = ME_GetParagraph(info->editor->pCursors[0].pRun);
-
-      /* Release possibly inherited cell definitions */
-      ME_DestroyTableCellList(para);
-
-      para->member.para.pCells = ALLOC_OBJ(ME_TableCell);
-      para->member.para.pCells->nRightBoundary = 0;
-      para->member.para.pCells->next = NULL;
-      para->member.para.pLastCell = para->member.para.pCells;
+      if (!info->tableDef)
+        info->tableDef = ALLOC_OBJ(RTFTable);
+      ZeroMemory(info->tableDef, sizeof(RTFTable));
       break;
     case rtfCellPos:
+      if (!info->tableDef)
+      {
+        info->tableDef = ALLOC_OBJ(RTFTable);
+        ZeroMemory(info->tableDef, sizeof(RTFTable));
+      }
+      if (info->tableDef->numCellsDefined >= MAX_TABLE_CELLS)
+        break;
+      info->tableDef->cells[info->tableDef->numCellsDefined].rightBoundary
= info->rtfParam;
+      {
+        /* Tab stops store the cell positions. */
+        ME_DisplayItem *para = ME_GetParagraph(info->editor->pCursors[0].pRun);
+        PARAFORMAT2 *pFmt = para->member.para.pFmt;
+        int cellNum = info->tableDef->numCellsDefined;
+        pFmt->rgxTabs[cellNum] &= ~0x00FFFFFF;
+        pFmt->rgxTabs[cellNum] = 0x00FFFFFF & info->rtfParam;
The trouble is, numCellsDefined is only guaranteed to be less than
MAX_TABLE_CELLS (defined as 63 in include/richedit.h), while rgxTabs
is of size MAX_TAB_STOPS, or 32.

I'm not sure what the correct fix is.  Would you mind having a look?
For what it's worth, this is Coverity id 727.

Thanks,
--Juan

1: http://source.winehq.org/git/wine.git/?a=commit;h=11c80396995065701205f2facb3dba10a6f8170f