Added validations for page index before using it.

dlls/comctl32/propsheet.c

@@ -1021,6 +1021,9 @@ static BOOL PROPSHEET_Back(HWND hwndDlg)
   PropSheetInfo* psInfo = (PropSheetInfo*) GetPropA(hwndDlg,
                                                     PropSheetInfoStr);
 
+  if (psInfo->active_page <= 0)
+     return FALSE;
+
   hdr.hwndFrom = hwndDlg;
   hdr.code = PSN_WIZBACK;
 
@@ -1053,6 +1056,9 @@ static BOOL PROPSHEET_Next(HWND hwndDlg)
   PropSheetInfo* psInfo = (PropSheetInfo*) GetPropA(hwndDlg,
                                                     PropSheetInfoStr);
 
+  if (psInfo->active_page < 0 || psInfo->active_page == psInfo->nPages - 1)
+     return FALSE;
+
   hdr.hwndFrom = hwndDlg;
   hdr.code = PSN_WIZNEXT;
 
@@ -1084,6 +1090,9 @@ static BOOL PROPSHEET_Finish(HWND hwndDlg)
   PropSheetInfo* psInfo = (PropSheetInfo*) GetPropA(hwndDlg,
                                                     PropSheetInfoStr);
 
+  if (psInfo->active_page < 0)
+     return FALSE;
+
   hdr.hwndFrom = hwndDlg;
   hdr.code = PSN_WIZFINISH;
 
@@ -1116,6 +1125,9 @@ static BOOL PROPSHEET_Apply(HWND hwndDlg)
   PropSheetInfo* psInfo = (PropSheetInfo*) GetPropA(hwndDlg,
                                                     PropSheetInfoStr);
 
+  if (psInfo->active_page < 0)
+     return FALSE;
+
   hdr.hwndFrom = hwndDlg;
 
   /*
@@ -1152,9 +1164,13 @@ static void PROPSHEET_Cancel(HWND hwndDlg)
 {
   PropSheetInfo* psInfo = (PropSheetInfo*) GetPropA(hwndDlg,
                                                     PropSheetInfoStr);
-  HWND hwndPage = psInfo->proppage[psInfo->active_page].hwndPage;
+  HWND hwndPage;
   NMHDR hdr;
 
+  if (psInfo->active_page < 0)
+     return;
+
+  hwndPage = psInfo->proppage[psInfo->active_page].hwndPage;
   hdr.hwndFrom = hwndDlg;
   hdr.code = PSN_QUERYCANCEL;
 
@@ -1178,9 +1194,13 @@ static void PROPSHEET_Help(HWND hwndDlg)
 {
   PropSheetInfo* psInfo = (PropSheetInfo*) GetPropA(hwndDlg,
                                                     PropSheetInfoStr);
-  HWND hwndPage = psInfo->proppage[psInfo->active_page].hwndPage;
+  HWND hwndPage;
   NMHDR hdr;
 
+  if (psInfo->active_page < 0)
+     return;
+
+  hwndPage = psInfo->proppage[psInfo->active_page].hwndPage;
   hdr.hwndFrom = hwndDlg;
   hdr.code = PSN_HELP;
 
@@ -1301,9 +1321,8 @@ static BOOL PROPSHEET_CanSetCurSel(HWND hwndDlg)
   HWND hwndPage;
   NMHDR hdr;
 
-  if (!psInfo)
-    return FALSE;
-
+  if (!psInfo || psInfo->active_page < 0)
+     return FALSE;
   /*
    * Notify the current page.
    */
@@ -1328,6 +1347,9 @@ static BOOL PROPSHEET_SetCurSel(HWND hwndDlg,
   HWND hwndHelp  = GetDlgItem(hwndDlg, IDHELP);
   NMHDR hdr;
 
+  if (psInfo->active_page < 0)
+     return FALSE;
+
   hwndPage = psInfo->proppage[psInfo->active_page].hwndPage;
 
   hdr.hwndFrom = hwndDlg;
@@ -1335,14 +1357,12 @@ static BOOL PROPSHEET_SetCurSel(HWND hwndDlg,
    * hpage takes precedence over index.
    */
   if (hpage != NULL)
-  {
     index = PROPSHEET_GetPageIndex(hpage, psInfo);
 
-    if (index == -1)
-    {
-      TRACE("Could not find page to remove!\n");
-      return FALSE;
-    }
+  if (index < 0 || index >= psInfo->nPages)
+  {
+    TRACE("Could not find page to select!\n");
+    return FALSE;
   }
 
   hwndPage = psInfo->proppage[index].hwndPage;
@@ -1804,6 +1824,8 @@ PROPSHEET_DialogProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
       HWND hwndTabCtrl = GetDlgItem(hwnd, IDC_TABCONTROL);
       LPCPROPSHEETPAGEA ppshpage;
 
+      SetPropA(hwnd, PropSheetInfoStr, (HANDLE)psInfo);
+
       /*
        * Small icon in the title bar.
        */
@@ -1868,9 +1890,6 @@ PROPSHEET_DialogProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
       if (!(psInfo->ppshheader->dwFlags & PSH_WIZARD))
         SendMessageA(hwndTabCtrl, TCM_SETCURSEL, psInfo->active_page, 0);
 
-      SetPropA(hwnd, PropSheetInfoStr, (HANDLE)psInfo);
-
-
       if (!HIWORD(psInfo->ppshheader->pszCaption) &&
               psInfo->ppshheader->hInstance)
       {