Marco Ivaldi <marco.ivaldi@mediaservice.net> has identified 3
vulnerabilities in CDE.
Two of them could affect our CDE (open-source version), while the 3rd
(sdtcm_convert) is Solaris specific.
The two vulnerabilities, both of which affect dtsession could allow a
local privilege escalation to root. A POC exists for Solaris. The
POC will not function on our CDE for two main reasons:
- the POC is Solaris specific
- The overflowed variables in question are allocated on the heap,
whereas in Solaris these variables are located on the stack.
The first vulnerability allows an extra long palette name to be used
to cause a crash via insufficient validation in
SrvPalette.c:CheckMonitor().
The second, which has not yet been assigned a CERT CVE resides in
SmCreateDirs.c:_DtCreateDtDirs() in libDtSvc. Due to insufficient
bounds checking, a crash or corruption can be achieved by using a very
long DISPLAY name.
This one is considered difficult to exploit, and no POC code is
available at this time. CDE 2.x code-bases are also listed as not
vulnerable, however some work has been done anyway to do some proper
bounds checking in this function.
The following text portions are copied from the relevant advisories,
which have not been released as of this writing.
NOTE: Oracle CDE does NOT use CDE 2.3.0a or earlier as mentioned
below. They are completely different code-bases):
Regarding CVE-2020-2692:
A buffer overflow in the CheckMonitor() function in the Common
Desktop Environment 2.3.0a and earlier, as distributed with Oracle
Solaris 10 1/13 (Update 11) and earlier, allows local users to gain
root privileges via a long palette name passed to dtsession in a
malicious .Xdefaults file.
Note that Oracle Solaris CDE is based on the original CDE 1.x train,
which is different from the CDE 2.x codebase that was later open
sourced. Most notably, the vulnerable buffer in the Oracle Solaris
CDE is stack-based, while in the open source version it is
heap-based.
Regarding the DtSvc bug, which does not currently have a CERT CVE:
A difficult to exploit stack-based buffer overflow in the
_DtCreateDtDirs() function in the Common Desktop Environment version
distributed with Oracle Solaris 10 1/13 (Update 11) and earlier may
allow local users to corrupt memory and potentially execute
arbitrary code in order to escalate privileges via a long X11
display name. The vulnerable function is located in the libDtSvc
library and can be reached by executing the setuid program
dtsession.
The open source version of CDE (based on the CDE 2.x codebase) is
not affected.
Fixes the following warning:
In file included from ../../../imports/x11/include/X11/Xutil.h:54,
from ../../../imports/x11/include/X11/Intrinsic.h:54,
from Action.c:64:
../../../imports/x11/include/X11/keysym.h:49:1: warning: "XK_MISCELLANY" redefined
<command-line>: warning: this is the location of the previous definition
<keysym.h> which includes all key symbols and loads <keysymdef.h>
is automaticlly included by the X Toolkit.
This patch removes #include <keysymdef.h> whenever not needed,
and adds #define XK_MISCALLANY in the source code where required.
This is a non-POSIX/ISO-C header. It is ok to include this on Linux, but it
is obsolete on BSD; FreeBSD even throws an error if you include it with
__STDC__ defined. Every system should nowadays have malloc() defined in
stdlib.h.
Diff is largely mechanical, replacing malloc.h with stdlib.h where it is not
yet included anyway.
Patch from Frederic Koehler <f.koehler427@gmail.com>:
These implicit definitions cause segfaults on x64 because
the implicit return type is a 32-bit signed int, rather than a pointer
type.
With Aaron's fixes to dtdbcache fixing a potential coredump, the
comment block in the write_db() function regarding tmpnam() no longer
applies, and the tmpnam_buf variable is no longer used.
So, remove them :)
Jon Trulson