diff --git a/Xext/EVI.c b/Xext/EVI.c
index 8fe3481..13bd32a 100644
--- a/Xext/EVI.c
+++ b/Xext/EVI.c
@@ -34,6 +34,7 @@ THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #include <X11/extensions/XEVIstr.h>
 #include "EVIstruct.h"
 #include "modinit.h"
+#include "scrnintstr.h"
 
 #if 0
 static unsigned char XEVIReqCode = 0;
@@ -87,10 +88,22 @@ ProcEVIGetVisualInfo(ClientPtr client)
 {
     REQUEST(xEVIGetVisualInfoReq);
     xEVIGetVisualInfoReply rep;
-    int n, n_conflict, n_info, sz_info, sz_conflict;
+    int i, n, n_conflict, n_info, sz_info, sz_conflict;
     VisualID32 *conflict;
+    unsigned int total_visuals = 0;
     xExtendedVisualInfo *eviInfo;
     int status;
+
+    /*
+     * do this first, otherwise REQUEST_FIXED_SIZE can overflow.  we assume
+     * here that you don't have more than 2^32 visuals over all your screens;
+     * this seems like a safe assumption.
+     */
+    for (i = 0; i < screenInfo.numScreens; i++)
+	total_visuals += screenInfo.screens[i]->numVisuals;
+    if (stuff->n_visual > total_visuals)
+	return BadValue;
+
     REQUEST_FIXED_SIZE(xEVIGetVisualInfoReq, stuff->n_visual * sz_VisualID32);
     status = eviPriv->getVisualInfo((VisualID32 *)&stuff[1], (int)stuff->n_visual,
 		&eviInfo, &n_info, &conflict, &n_conflict);
diff --git a/Xext/sampleEVI.c b/Xext/sampleEVI.c
index 7508aa7..b274b8d 100644
--- a/Xext/sampleEVI.c
+++ b/Xext/sampleEVI.c
@@ -34,6 +34,13 @@ THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #include <X11/extensions/XEVIstr.h>
 #include "EVIstruct.h"
 #include "scrnintstr.h"
+
+#if HAVE_STDINT_H
+#include <stdint.h>
+#elif !defined(INT_MAX)
+#define UINT32_MAX 0xffffffffU
+#endif
+
 static int sampleGetVisualInfo(
     VisualID32 *visual,
     int n_visual,
@@ -42,24 +49,36 @@ static int sampleGetVisualInfo(
     VisualID32 **conflict_rn,
     int *n_conflict_rn)
 {
-    int max_sz_evi = n_visual * sz_xExtendedVisualInfo * screenInfo.numScreens;
+    unsigned int max_sz_evi;
     VisualID32 *temp_conflict;
     xExtendedVisualInfo *evi;
-    int max_visuals = 0, max_sz_conflict, sz_conflict = 0;
+    unsigned int max_visuals = 0, max_sz_conflict, sz_conflict = 0;
     register int visualI, scrI, sz_evi = 0, conflictI, n_conflict;
-    *evi_rn = evi = (xExtendedVisualInfo *)xalloc(max_sz_evi);
-    if (!*evi_rn)
-         return BadAlloc;
+
+    if (n_visual > UINT32_MAX/(sz_xExtendedVisualInfo * screenInfo.numScreens))
+	return BadAlloc;
+    max_sz_evi = n_visual * sz_xExtendedVisualInfo * screenInfo.numScreens;
+    
     for (scrI = 0; scrI < screenInfo.numScreens; scrI++) {
         if (screenInfo.screens[scrI]->numVisuals > max_visuals)
             max_visuals = screenInfo.screens[scrI]->numVisuals;
     }
+
+    if (n_visual > UINT32_MAX/(sz_VisualID32 * screenInfo.numScreens 
+			       * max_visuals)) 
+	return BadAlloc;
     max_sz_conflict = n_visual * sz_VisualID32 * screenInfo.numScreens * max_visuals;
+
+    *evi_rn = evi = (xExtendedVisualInfo *)xalloc(max_sz_evi);
+    if (!*evi_rn)
+         return BadAlloc;
+
     temp_conflict = (VisualID32 *)xalloc(max_sz_conflict);
     if (!temp_conflict) {
         xfree(*evi_rn);
         return BadAlloc;
     }
+
     for (scrI = 0; scrI < screenInfo.numScreens; scrI++) {
         for (visualI = 0; visualI < n_visual; visualI++) {
 	    evi[sz_evi].core_visual_id = visual[visualI];