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glx: check for indirect context in CreateContextAttribsARB()

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Commit 99f0365b "Add a command line argument for disabling indirect GLX"
added a test to check if indirect context are enabled in
`DoCreateContext()` but `__glXDisp_CreateContextAttribsARB()` doesn't
use `DoCreateContext()` and doesn't check if indirect context is
enabled.

As a result, clients can still manage to create indirect contexts using
`glXCreateContextAttribsARB()` even if indirect contexts are disabled,
which can possibly crash Xservers such as Xwayland or Xephyr when the
context is destroyed.

To avoid the issue, check for `enableIndirectGLX` in
`__glXDisp_CreateContextAttribsARB()` as well.

Fixes: 99f0365b "Add a command line argument for disabling indirect GLX"
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107508
Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
This commit is contained in:
Olivier Fourdan 2018-09-05 15:20:17 +02:00 committed by ajax
parent ce271535ad
commit 75448671ab
1 changed files with 12 additions and 0 deletions
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12
glx/createcontext.c
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@ -28,6 +28,7 @@
#include "glxserver.h"
#include "glxext.h"
#include "indirect_dispatch.h"
#include "opaque.h"
#define ALL_VALID_FLAGS \
(GLX_CONTEXT_DEBUG_BIT_ARB | GLX_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB \
@ -320,6 +321,17 @@ __glXDisp_CreateContextAttribsARB(__GLXclientState * cl, GLbyte * pc)
err = BadAlloc;
}
else {
/* Only allow creating indirect GLX contexts if allowed by
* server command line. Indirect GLX is of limited use (since
* it's only GL 1.4), it's slower than direct contexts, and
* it's a massive attack surface for buffer overflow type
* errors.
*/
if (!enableIndirectGLX) {
client->errorValue = req->isDirect;
return BadValue;
}
ctx = glxScreen->createContext(glxScreen, config, shareCtx,
req->numAttribs, (uint32_t *) attribs,
&err);