From a2af6cb8a699966e13c0bbcafc41da2f0e814b86 Mon Sep 17 00:00:00 2001
From: Adam Jackson <ajax@redhat.com>
Date: Mon, 10 Nov 2014 12:13:43 -0500
Subject: [PATCH 30/31] 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>
Signed-off-by: Fedora X Ninjas <x@fedoraproject.org>
---
glx/glxcmds.c | 57 ++++++++++++++++++++++++++++++++++-----------------------
1 file changed, 34 insertions(+), 23 deletions(-)
diff --git a/glx/glxcmds.c b/glx/glxcmds.c
index 969bf01..4715328 100644
--- a/glx/glxcmds.c
+++ b/glx/glxcmds.c
@@ -2055,6 +2055,8 @@ __glXDisp_RenderLarge(__GLXclientState * cl, GLbyte * pc)
__GLX_DECLARE_SWAP_VARIABLES;
+ REQUEST_AT_LEAST_SIZE(xGLXRenderLargeReq);
+
req = (xGLXRenderLargeReq *) pc;
if (client->swapped) {
__GLX_SWAP_SHORT(&req->length);
@@ -2070,12 +2072,14 @@ __glXDisp_RenderLarge(__GLXclientState * cl, GLbyte * pc)
__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);
@@ -2085,7 +2089,7 @@ __glXDisp_RenderLarge(__GLXclientState * cl, GLbyte * pc)
if (cl->largeCmdRequestsSoFar == 0) {
__GLXrenderSizeData entry;
- int extra;
+ int extra = 0;
size_t cmdlen;
int err;
@@ -2098,13 +2102,17 @@ __glXDisp_RenderLarge(__GLXclientState * cl, GLbyte * pc)
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.
@@ -2126,17 +2134,13 @@ __glXDisp_RenderLarge(__GLXclientState * cl, GLbyte * pc)
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.
*/
@@ -2166,6 +2170,7 @@ __glXDisp_RenderLarge(__GLXclientState * cl, GLbyte * pc)
** 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.
@@ -2184,11 +2189,18 @@ __glXDisp_RenderLarge(__GLXclientState * cl, GLbyte * pc)
/*
** 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++;
@@ -2200,17 +2212,16 @@ __glXDisp_RenderLarge(__GLXclientState * cl, GLbyte * pc)
** 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);
--
1.9.3
