X.Org Security Advisory: May 23, 2013
Protocol handling issues in X Window System client libraries
Description:
Ilja van Sprundel, a security researcher with IOActive, has discovered
a large number of issues in the way various X client libraries handle
the responses they receive from servers, and has worked with X.Org's
security team to analyze, confirm, and fix these issues.
Most of these issues stem from the client libraries trusting the server
to send correct protocol data, and not verifying that the values will
not overflow or cause other damage. Most of the time X clients servers
are run by the same user, with the server more privileged from the clients,
so this is not a problem, but there are scenarios in which a privileged
client can be connected to an unprivileged server, for instance, connecting
a setuid X client (such as a screen lock program) to a virtual X server
(such as Xvfb or Xephyr) which the user has modified to return invalid
data, potentially allowing the user to escalate their privileges.
The X.Org security team would like to take this opportunity to remind
X client authors that current best practices suggest separating code
that requires privileges from the GUI, to reduce the attack surface of
issues like this.
The vulnerabilities include:
- integer overflows calculating memory needs for replies
These calls do not check that their calculations for how much memory
is needed to handle the returned data have not overflowed, so can
result in allocating too little memory and then writing the returned
data past the end of the allocated buffer.
* CVE-2013-1981: libX11 1.5.99.901 (1.6 RC1) and earlier
Affected functions: XQueryFont(), _XF86BigfontQueryFont(),
XListFontsWithInfo(), XGetMotionEvents(), XListHosts(),
XGetModifierMapping(), XGetPointerMapping(), XGetKeyboardMapping(),
XGetWindowProperty(), XGetImage()
* CVE-2013-1982: libXext 1.3.1 and earlier
Affected functions: XcupGetReservedColormapEntries(),
XcupStoreColors(), XdbeGetVisualInfo(), XeviGetVisualInfo(),
XShapeGetRectangles(), XSyncListSystemCounters()
* CVE-2013-1983: libXfixes 5.0 and earlier
Affected functions: XFixesGetCursorImage()
* CVE-2013-1984: libXi 1.7.1 and earlier
Affected functions: XGetDeviceControl(), XGetFeedbackControl(),
XGetDeviceDontPropagateList(), XGetDeviceMotionEvents(),
XIGetProperty(), XIGetSelectedEvents(), XGetDeviceProperties(),
XListInputDevices()
* CVE-2013-1985: libXinerama 1.1.2 and earlier
Affected functions: XineramaQueryScreens()
* CVE-2013-2062: libXp 1.0.1 and earlier
Affected functions: XpGetAttributes(), XpGetOneAttribute(),
XpGetPrinterList(), XpQueryScreens()
* CVE-2013-1986: libXrandr 1.4.0 and earlier
Affected functions: XRRQueryOutputProperty(), XRRQueryProviderProperty()
[XRRQueryProviderProperty() was introduced in libXrandr 1.4.0 and is
not found in 1.3.2 and older releases.]
* CVE-2013-1987: libXrender 0.9.7 and earlier
Affected functions: XRenderQueryFilters(), XRenderQueryFormats(),
XRenderQueryPictIndexValues()
* CVE-2013-1988: libXRes 1.0.6 and earlier
Affected functions: XResQueryClients(), XResQueryClientResources()
* CVE-2013-2063: libXtst 1.2.1 and earlier
Affected functions: XRecordGetContext()
* CVE-2013-1989: libXv 1.0.7 and earlier
Affected functions: XvQueryPortAttributes(), XvListImageFormats(),
XvCreateImage()
* CVE-2013-1990: libXvMC 1.0.7 and earlier
Affected functions: XvMCListSurfaceTypes(), XvMCListSubpictureTypes()
* CVE-2013-1991: libXxf86dga 1.1.3 and earlier
Affected functions: XDGAQueryModes(), XDGASetMode()
* CVE-2013-1992: libdmx 1.1.2 and earlier
Affected functions: DMXGetScreenAttributes(), DMXGetWindowAttributes(),
DMXGetInputAttributes()
* CVE-2013-2064: libxcb 1.9 and earlier
Affected functions: read_packet()
* CVE-2013-1993: libGLX in Mesa 9.1.1 and earlier
Affected functions: XF86DRIOpenConnection(), XF86DRIGetClientDriverName()
* CVE-2013-1994: libchromeXvMC libchromeXvMCPro in openChrome 0.3.2
and earlier
Affected functions: uniDRIOpenConnection(), uniDRIGetClientDriverName()
- sign extension issues calculating memory needs for replies
These calls do not check that their calculations for how much memory
is needed to handle the returned data have not had sign extension
issues when converting smaller integer types to larger ones, leading
to negative numbers being used in memory size calculations that can
result in allocating too little memory and then writing the returned
data past the end of the allocated buffer.
* CVE-2013-1995: libXi 1.7.1 and earlier
Affected
