diff --git a/dix/dispatch.c b/dix/dispatch.c
index b3e5feacc..2308cfe6d 100644
--- a/dix/dispatch.c
+++ b/dix/dispatch.c
@@ -527,9 +527,10 @@ Dispatch(void)
 
                 /* now, finally, deal with client requests */
                 result = ReadRequestFromClient(client);
-                if (result <= 0) {
-                    if (result < 0)
-                        CloseDownClient(client);
+                if (result == 0)
+                    break;
+                else if (result == -1) {
+                    CloseDownClient(client);
                     break;
                 }
 
@@ -550,7 +551,7 @@ Dispatch(void)
                                           client->index,
                                           client->requestBuffer);
 #endif
-                if (result > (maxBigRequestSize << 2))
+                if (result < 0 || result > (maxBigRequestSize << 2))
                     result = BadLength;
                 else {
                     result = XaceHookDispatch(client, client->majorOp);
diff --git a/os/io.c b/os/io.c
index 1fffaf62c..3e39c10e6 100644
--- a/os/io.c
+++ b/os/io.c
@@ -300,6 +300,10 @@ ReadRequestFromClient(ClientPtr client)
                 needed = get_big_req_len(request, client);
         }
         client->req_len = needed;
+        if (needed > MAXINT >> 2) {
+            /* Check for potential integer overflow */
+            return -(BadLength);
+        }
         needed <<= 2;           /* needed is in bytes now */
     }
     if (gotnow < needed) {