glx: Top-level length checking for swapped VendorPrivate requests [CVE-2014-8098 4/8]

Reviewed-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Julien Cristau <jcristau@debian.org>
Reviewed-by: Michal Srb <msrb@suse.com>
Reviewed-by: Andy Ritger <aritger@nvidia.com>
Signed-off-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>

glx/glxcmdsswap.c

@@ -958,11 +958,13 @@ __glXDispSwap_RenderLarge(__GLXclientState * cl, GLbyte * pc)
 int
 __glXDispSwap_VendorPrivate(__GLXclientState * cl, GLbyte * pc)
 {
+    ClientPtr client = cl->client;
     xGLXVendorPrivateReq *req;
     GLint vendorcode;
     __GLXdispatchVendorPrivProcPtr proc;
 
     __GLX_DECLARE_SWAP_VARIABLES;
+    REQUEST_AT_LEAST_SIZE(xGLXVendorPrivateReq);
 
     req = (xGLXVendorPrivateReq *) pc;
     __GLX_SWAP_SHORT(&req->length);
@@ -985,11 +987,13 @@ __glXDispSwap_VendorPrivate(__GLXclientState * cl, GLbyte * pc)
 int
 __glXDispSwap_VendorPrivateWithReply(__GLXclientState * cl, GLbyte * pc)
 {
+    ClientPtr client = cl->client;
     xGLXVendorPrivateWithReplyReq *req;
     GLint vendorcode;
     __GLXdispatchVendorPrivProcPtr proc;
 
     __GLX_DECLARE_SWAP_VARIABLES;
+    REQUEST_AT_LEAST_SIZE(xGLXVendorPrivateWithReplyReq);
 
     req = (xGLXVendorPrivateWithReplyReq *) pc;
     __GLX_SWAP_SHORT(&req->length);