mesa/src/glx/glx_query.c

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/*
* (C) Copyright IBM Corporation 2004
* All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* on the rights to use, copy, modify, merge, publish, distribute, sub
* license, and/or sell copies of the Software, and to permit persons to whom
* the Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
* IBM AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
/**
* \file glx_query.c
* Generic utility functions to query internal data from the server.
*
* \author Ian Romanick <idr@us.ibm.com>
*/
#include "glxclient.h"
# include <X11/Xlib-xcb.h>
# include <xcb/xcb.h>
# include <xcb/glx.h>
/**
* Exchange a protocol request for glXQueryServerString.
*/
char *
__glXQueryServerString(Display * dpy, CARD32 screen, CARD32 name)
{
xcb_connection_t *c = XGetXCBConnection(dpy);
xcb_glx_query_server_string_reply_t *reply =
xcb_glx_query_server_string_reply(c,
xcb_glx_query_server_string(c,
screen,
name),
NULL);
glx: Fix SEGV due to dereferencing a NULL ptr from XCB-GLX. When run in optirun, applications that linked to `libGLX.so` and then proceeded to querying Mesa for extension strings caused a SEGV in Mesa. `glXQueryExtensionsString` was calling a chain of functions that eventually led to `__glXQueryServerString`. This function would call `xcb_glx_query_server_string` then `xcb_glx_query_server_string_reply`. The latter for some unknown reason returned `NULL`. Passing this `NULL` to `xcb_glx_query_server_string_string_length` would cause a SEGV as the function tried to dereference it. The reason behind the function returning `NULL` is yet to be determined, however, simply checking that the ptr is not `NULL` resolves this. A similar check has been added to `__glXGetString` for completeness sake, although not immediately necessary. In addition to that, we stumbled into a similar problem in `AllocAndFetchScreenConfigs` which tries to access the configs to free them if `__glXQueryServerString` fails. This, of course, SEGVs, because the configs are yet to have been allocated. Simply continuing past the configs if their config ptrs are `NULL` resolves this. We also switch to `calloc` to make sure that the config ptrs are `NULL` by default, and not some uninitialized value. Cc: mesa-stable@lists.freedesktop.org Fixes: 24b8a8cfe821 "glx: implement __glXGetString, hide __glXGetStringFromServer" Fixes: cb3610e37c4c "Import the GLX client side library, formerly from xc/lib/GL/glx. Build it " Reviewed-by: Adam Jackson <ajax@redhat.com> Signed-off-by: Hal Gentz <zegentzy@protonmail.com>
2019-07-25 22:40:50 +01:00
if (!reply)
return NULL;
/* The spec doesn't mention this, but the Xorg server replies with
* a string already terminated with '\0'. */
uint32_t len = xcb_glx_query_server_string_string_length(reply);
char *buf = malloc(len);
memcpy(buf, xcb_glx_query_server_string_string(reply), len);
free(reply);
return buf;
}
/**
* Exchange a protocol request for glGetString.
*/
char *
__glXGetString(Display * dpy, CARD32 contextTag, CARD32 name)
{
xcb_connection_t *c = XGetXCBConnection(dpy);
xcb_glx_get_string_reply_t *reply = xcb_glx_get_string_reply(c,
xcb_glx_get_string
(c,
contextTag,
name),
NULL);
glx: Fix SEGV due to dereferencing a NULL ptr from XCB-GLX. When run in optirun, applications that linked to `libGLX.so` and then proceeded to querying Mesa for extension strings caused a SEGV in Mesa. `glXQueryExtensionsString` was calling a chain of functions that eventually led to `__glXQueryServerString`. This function would call `xcb_glx_query_server_string` then `xcb_glx_query_server_string_reply`. The latter for some unknown reason returned `NULL`. Passing this `NULL` to `xcb_glx_query_server_string_string_length` would cause a SEGV as the function tried to dereference it. The reason behind the function returning `NULL` is yet to be determined, however, simply checking that the ptr is not `NULL` resolves this. A similar check has been added to `__glXGetString` for completeness sake, although not immediately necessary. In addition to that, we stumbled into a similar problem in `AllocAndFetchScreenConfigs` which tries to access the configs to free them if `__glXQueryServerString` fails. This, of course, SEGVs, because the configs are yet to have been allocated. Simply continuing past the configs if their config ptrs are `NULL` resolves this. We also switch to `calloc` to make sure that the config ptrs are `NULL` by default, and not some uninitialized value. Cc: mesa-stable@lists.freedesktop.org Fixes: 24b8a8cfe821 "glx: implement __glXGetString, hide __glXGetStringFromServer" Fixes: cb3610e37c4c "Import the GLX client side library, formerly from xc/lib/GL/glx. Build it " Reviewed-by: Adam Jackson <ajax@redhat.com> Signed-off-by: Hal Gentz <zegentzy@protonmail.com>
2019-07-25 22:40:50 +01:00
if (!reply)
return NULL;
/* The spec doesn't mention this, but the Xorg server replies with
* a string already terminated with '\0'. */
uint32_t len = xcb_glx_get_string_string_length(reply);
char *buf = malloc(len);
memcpy(buf, xcb_glx_get_string_string(reply), len);
free(reply);
return buf;
}