[X2Go-Dev] [X2Go-Commits] [nx-libs] 51/52: glx: Length checking for RenderLarge requests (v2) [CVE-2014-8098 3/8] (v3)
Mihai Moldovan
ionic at ionic.de
Mon Feb 16 02:23:35 CET 2015
On 14.02.2015 05:47 PM, git-admin at x2go.org wrote:
> This is an automated email from the git hooks/post-receive script.
>
> x2go pushed a commit to branch 3.6.x
> in repository nx-libs.
>
> commit 9c558f9ca2c0d4e34fa71dff272ed1c39c22cd9d
> Author: Adam Jackson <ajax at redhat.com>
> Date: Mon Nov 10 12:13:43 2014 -0500
>
> glx: Length checking for RenderLarge requests (v2) [CVE-2014-8098 3/8] (v3)
>
> 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)
>
> v3: backport to RHEL5
>
> v4: backport to nx-libs 3.6.x (Mike DePaulo)
>
> Reviewed-by: Michal Srb <msrb at suse.com>
> Reviewed-by: Andy Ritger <aritger at nvidia.com>
> Signed-off-by: Adam Jackson <ajax at redhat.com>
> Signed-off-by: Alan Coopersmith <alan.coopersmith at oracle.com>
> Signed-off-by: Fedora X Ninjas <x at fedoraproject.org>
> Signed-off-by: Dave Airlie <airlied at redhat.com>
>
> fixup swap
> ---
> nx-X11/programs/Xserver/GL/glx/glxcmds.c | 58 +++++++++++++++----------
> nx-X11/programs/Xserver/GL/glx/glxcmdsswap.c | 59 ++++++++++++++++----------
> 2 files changed, 71 insertions(+), 46 deletions(-)
>
> diff --git a/nx-X11/programs/Xserver/GL/glx/glxcmds.c b/nx-X11/programs/Xserver/GL/glx/glxcmds.c
> index 831c65b..20c12f3 100644
> --- a/nx-X11/programs/Xserver/GL/glx/glxcmds.c
> +++ b/nx-X11/programs/Xserver/GL/glx/glxcmds.c
> @@ -1535,6 +1535,8 @@ int __glXRenderLarge(__GLXclientState *cl, GLbyte *pc)
> ** duplicated there.
> */
>
> + REQUEST_AT_LEAST_SIZE(xGLXRenderLargeReq);
> +
> req = (xGLXRenderLargeReq *) pc;
> glxc = __glXForceCurrent(cl, req->contextTag, &error);
> if (!glxc) {
> @@ -1542,12 +1544,15 @@ int __glXRenderLarge(__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);
> @@ -1557,7 +1562,7 @@ int __glXRenderLarge(__GLXclientState *cl, GLbyte *pc)
>
> if (cl->largeCmdRequestsSoFar == 0) {
> __GLXrenderSizeData *entry;
> - int extra, cmdlen;
> + int extra = 0, cmdlen;
> /*
> ** This is the first request of a multi request command.
> ** Make enough space in the buffer, then copy the entire request.
> @@ -1567,9 +1572,13 @@ int __glXRenderLarge(__GLXclientState *cl, GLbyte *pc)
> return __glXBadLargeRequest;
> }
>
> + if (dataBytes < __GLX_RENDER_LARGE_HDR_SIZE)
> + return BadLength;
> +
> hdr = (__GLXrenderLargeHeader *) pc;
> - cmdlen = hdr->length;
> opcode = hdr->opcode;
> + if ((cmdlen = safe_pad(hdr->length)) < 0)
> + return BadLength;
>
> /*
> ** Check for core opcodes and grab entry data.
> @@ -1603,16 +1612,13 @@ int __glXRenderLarge(__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.
> */
> @@ -1641,6 +1647,7 @@ int __glXRenderLarge(__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.
> @@ -1659,7 +1666,13 @@ int __glXRenderLarge(__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 __glXBadLargeRequest;
> + }
> +
> + if (bytesSoFar > cl->largeCmdBytesTotal) {
> client->errorValue = dataBytes;
> __glXResetLargeCommandStatus(cl);
> return __glXBadLargeRequest;
> @@ -1673,17 +1686,16 @@ int __glXRenderLarge(__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) {
cl->largeCmdBytesTotal is not wrapped in safe_pad(). This looks odd and could be a mistake.
> client->errorValue = dataBytes;
> __glXResetLargeCommandStatus(cl);
> return __glXBadLargeRequest;
> diff --git a/nx-X11/programs/Xserver/GL/glx/glxcmdsswap.c b/nx-X11/programs/Xserver/GL/glx/glxcmdsswap.c
> index 2685355..2e228c0 100644
> --- a/nx-X11/programs/Xserver/GL/glx/glxcmdsswap.c
> +++ b/nx-X11/programs/Xserver/GL/glx/glxcmdsswap.c
> @@ -587,6 +587,8 @@ int __glXSwapRenderLarge(__GLXclientState *cl, GLbyte *pc)
> ** duplicated there.
> */
>
> + REQUEST_AT_LEAST_SIZE(xGLXRenderLargeReq);
> +
> req = (xGLXRenderLargeReq *) pc;
> __GLX_SWAP_SHORT(&req->length);
> __GLX_SWAP_INT(&req->contextTag);
> @@ -599,12 +601,15 @@ int __glXSwapRenderLarge(__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);
> @@ -614,7 +619,7 @@ int __glXSwapRenderLarge(__GLXclientState *cl, GLbyte *pc)
>
> if (cl->largeCmdRequestsSoFar == 0) {
> __GLXrenderSizeData *entry;
> - int extra;
> + int extra = 0;
> size_t cmdlen;
> /*
> ** This is the first request of a multi request command.
> @@ -624,12 +629,17 @@ int __glXSwapRenderLarge(__GLXclientState *cl, GLbyte *pc)
> client->errorValue = req->requestNumber;
> return __glXBadLargeRequest;
> }
> + if (dataBytes < __GLX_RENDER_LARGE_HDR_SIZE)
> + return BadLength;
> +
> hdr = (__GLXrenderLargeHeader *) pc;
> __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;
> +
> if ( (opcode >= __GLX_MIN_RENDER_OPCODE) &&
> (opcode <= __GLX_MAX_RENDER_OPCODE) ) {
> entry = &__glXRenderSizeTable[opcode];
> @@ -661,16 +671,12 @@ int __glXSwapRenderLarge(__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.
> */
> @@ -698,6 +704,7 @@ int __glXSwapRenderLarge(__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.
> @@ -716,7 +723,13 @@ int __glXSwapRenderLarge(__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 __glXBadLargeRequest;
> + }
> +
> + if (bytesSoFar > cl->largeCmdBytesTotal) {
> client->errorValue = dataBytes;
> __glXResetLargeCommandStatus(cl);
> return __glXBadLargeRequest;
> @@ -730,17 +743,17 @@ int __glXSwapRenderLarge(__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) {
Similarly not wrapped in safe_pad() here. Not sure whether this happened
on purpose or is an error.
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