--- /dev/null
+From 6070d07a25b33e9630f8dbbde1d1df6f25164286 Mon Sep 17 00:00:00 2001
+From: Adam Jackson <ajax@redhat.com>
+Date: Mon, 10 Nov 2014 12:13:43 -0500
+Subject: [PATCH 27/33] glx: Length checking for RenderLarge requests (v2)
+ [CVE-2014-8098 3/8]
+
+This is a half-measure until we start passing request length into the
+varsize function, but it's better than the nothing we had before.
+
+v2: Verify that there's at least a large render header's worth of
+dataBytes (Julien Cristau)
+
+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/glxcmds.c | 57 ++++++++++++++++++++++++++++++++++-----------------------
+ 1 file changed, 34 insertions(+), 23 deletions(-)
+
+Index: xorg-server-1.15.1/glx/glxcmds.c
+===================================================================
+--- xorg-server-1.15.1.orig/glx/glxcmds.c 2014-12-04 11:56:22.749376887 -0500
++++ xorg-server-1.15.1/glx/glxcmds.c 2014-12-04 11:56:22.745376862 -0500
+@@ -2099,6 +2099,8 @@
+
+ __GLX_DECLARE_SWAP_VARIABLES;
+
++ REQUEST_AT_LEAST_SIZE(xGLXRenderLargeReq);
++
+ req = (xGLXRenderLargeReq *) pc;
+ if (client->swapped) {
+ __GLX_SWAP_SHORT(&req->length);
+@@ -2114,12 +2116,14 @@
+ __glXResetLargeCommandStatus(cl);
+ return error;
+ }
++ if (safe_pad(req->dataBytes) < 0)
++ return BadLength;
+ dataBytes = req->dataBytes;
+
+ /*
+ ** Check the request length.
+ */
+- if ((req->length << 2) != __GLX_PAD(dataBytes) + sz_xGLXRenderLargeReq) {
++ if ((req->length << 2) != safe_pad(dataBytes) + sz_xGLXRenderLargeReq) {
+ client->errorValue = req->length;
+ /* Reset in case this isn't 1st request. */
+ __glXResetLargeCommandStatus(cl);
+@@ -2129,7 +2133,7 @@
+
+ if (cl->largeCmdRequestsSoFar == 0) {
+ __GLXrenderSizeData entry;
+- int extra;
++ int extra = 0;
+ size_t cmdlen;
+ int err;
+
+@@ -2142,13 +2146,17 @@
+ return __glXError(GLXBadLargeRequest);
+ }
+
++ if (dataBytes < __GLX_RENDER_LARGE_HDR_SIZE)
++ return BadLength;
++
+ hdr = (__GLXrenderLargeHeader *) pc;
+ if (client->swapped) {
+ __GLX_SWAP_INT(&hdr->length);
+ __GLX_SWAP_INT(&hdr->opcode);
+ }
+- cmdlen = hdr->length;
+ opcode = hdr->opcode;
++ if ((cmdlen = safe_pad(hdr->length)) < 0)
++ return BadLength;
+
+ /*
+ ** Check for core opcodes and grab entry data.
+@@ -2170,17 +2178,13 @@
+ if (extra < 0) {
+ return BadLength;
+ }
+- /* large command's header is 4 bytes longer, so add 4 */
+- if (cmdlen != __GLX_PAD(entry.bytes + 4 + extra)) {
+- return BadLength;
+- }
+ }
+- else {
+- /* constant size command */
+- if (cmdlen != __GLX_PAD(entry.bytes + 4)) {
+- return BadLength;
+- }
++
++ /* the +4 is safe because we know entry.bytes is small */
++ if (cmdlen != safe_pad(safe_add(entry.bytes + 4, extra))) {
++ return BadLength;
+ }
++
+ /*
+ ** Make enough space in the buffer, then copy the entire request.
+ */
+@@ -2207,6 +2211,7 @@
+ ** We are receiving subsequent (i.e. not the first) requests of a
+ ** multi request command.
+ */
++ int bytesSoFar; /* including this packet */
+
+ /*
+ ** Check the request number and the total request count.
+@@ -2225,11 +2230,18 @@
+ /*
+ ** Check that we didn't get too much data.
+ */
+- if ((cl->largeCmdBytesSoFar + dataBytes) > cl->largeCmdBytesTotal) {
++ if ((bytesSoFar = safe_add(cl->largeCmdBytesSoFar, dataBytes)) < 0) {
+ client->errorValue = dataBytes;
+ __glXResetLargeCommandStatus(cl);
+ return __glXError(GLXBadLargeRequest);
+ }
++
++ if (bytesSoFar > cl->largeCmdBytesTotal) {
++ client->errorValue = dataBytes;
++ __glXResetLargeCommandStatus(cl);
++ return __glXError(GLXBadLargeRequest);
++ }
++
+ memcpy(cl->largeCmdBuf + cl->largeCmdBytesSoFar, pc, dataBytes);
+ cl->largeCmdBytesSoFar += dataBytes;
+ cl->largeCmdRequestsSoFar++;
+@@ -2241,17 +2253,16 @@
+ ** This is the last request; it must have enough bytes to complete
+ ** the command.
+ */
+- /* NOTE: the two pad macros have been added below; they are needed
+- ** because the client library pads the total byte count, but not
+- ** the per-request byte counts. The Protocol Encoding says the
+- ** total byte count should not be padded, so a proposal will be
+- ** made to the ARB to relax the padding constraint on the total
+- ** byte count, thus preserving backward compatibility. Meanwhile,
+- ** the padding done below fixes a bug that did not allow
+- ** large commands of odd sizes to be accepted by the server.
++ /* NOTE: the pad macro below is needed because the client library
++ ** pads the total byte count, but not the per-request byte counts.
++ ** The Protocol Encoding says the total byte count should not be
++ ** padded, so a proposal will be made to the ARB to relax the
++ ** padding constraint on the total byte count, thus preserving
++ ** backward compatibility. Meanwhile, the padding done below
++ ** fixes a bug that did not allow large commands of odd sizes to
++ ** be accepted by the server.
+ */
+- if (__GLX_PAD(cl->largeCmdBytesSoFar) !=
+- __GLX_PAD(cl->largeCmdBytesTotal)) {
++ if (safe_pad(cl->largeCmdBytesSoFar) != cl->largeCmdBytesTotal) {
+ client->errorValue = dataBytes;
+ __glXResetLargeCommandStatus(cl);
+ return __glXError(GLXBadLargeRequest);
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