Upstream ksh has removed it's builtin aliases, favoring instead to make them
all builtin commands, this would also allow us to skip having to manually
merge another file, it was explained best in this email:
"Default aliases are an ugly hack that you are better off without.
Disadvantages include:
- 'unalias -a' becomes basically unusable as it gets rid of commands you
probably want;
- shell functions by those names are ignored (unless you quote their
names upon invocation);
- something like 'cmdname=foo; "$cmdname" bar baz' doesn't work if
$cmdname is an alias.
I strongly recommend removing the BLT_SPC flag from all of
your extra dtksh builtins. Making builtins "special builtins" is of no
real benefit at all, while introducing a pointless restriction: shell
functions by those names cannot be defined, which causes a risk of
incompatibility with scripts written for other shells. The BLT_SPC flag
is for a very few historic builtins that must have certain weird
corner-case behaviour of "special" builtins for POSIX compliance and
Bourne shell compatibility reasons."
Some of these functions were returning pointers cast as integers,
which of course is bad on a 64b LP64 systems.
This code should probably just be refactored at some point. There may
be other hidden issues, and all the casting just sucks.
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.
One-off error:
Old buffer length was 6 for one character (3 * 1 + 3)
We need one more byte par character in the buffer for
the hex representation of it.
+0 '"'
+1 '\\'
+2 'x'
+3 'f'
+4 'c'
+5 '"'
+6 0x0 << overflow
tcl combined with RCHECK will abort because memory blocks
are allocated contiguously and we overwrite the magic marker
of the next block.
This fixes a potentially exploitable buffer overrun in dtprintinfo.
This was brought to my attention based on a 0day exploit released for
Solaris CDE.
The exploit code does not work (or build) on linux, and the overrun is
in the heap rather than the stack as on Solaris, but it's easy to see
how this could be exploited.
The following is the content of the advisory:
8<-----------------------------------------------------------
@Mediaservice.net (Cybaze Group) Security Advisory #2019-01 (2019-05-07)
Title: Local privilege escalation via CDE dtprintinfo
Application: Common Desktop Environment 2.3.0 and earlier
Platforms: Oracle Solaris 10 1/13 (Update 11) and earlier
Description: A local attacker can gain root privileges by exploiting
a buffer overflow in CDE dtprintinfo
Author: Marco Ivaldi <marco.ivaldi@mediaservice.net>
Contributor: Dave Aitel <dave.aitel@cyxtera.com> (original discovery)
Vendor Status: <secalert_us@oracle.com> notified on 2019-05-05
<cdesktopenv-devel@lists.sourceforge.net> notified on 2019-05-05
CVE: The Common Vulnerabilities and Exposures project has not assigned
a name to this issue yet
References: https://lab.mediaservice.net/advisory/2019-01-cde-dtprintinfo.txthttps://github.com/0xdea/raptor_infiltrate19https://sourceforge.net/p/cdesktopenv/wiki/Home/https://www.oracle.com/technetwork/server-storage/solaris10/https://www.mediaservice.net/https://infiltratecon.com/
1. Abstract.
A buffer overflow in the DtPrinterAction::PrintActionExists() function in the
Common Desktop Environment 2.3.0 and earlier, as used in Oracle Solaris 10 1/13
(Update 11) and earlier, allows local users to gain root privileges via a long
printer name passed to dtprintinfo by a malicious lpstat program.
This is a 0day vulnerability demonstrated at #INFILTRATE19 on May 2nd, 2019 in
the talk "A bug's life: story of a Solaris 0day".
2. Example Attack Session.
bash-3.2$ cat /etc/release
Oracle Solaris 10 1/13 s10x_u11wos_24a X86
Copyright (c) 1983, 2013, Oracle and/or its affiliates. All rights reserved.
Assembled 17 January 2013
bash-3.2$ uname -a
SunOS nostalgia 5.10 Generic_147148-26 i86pc i386 i86pc
bash-3.2$ id
uid=54322(raptor) gid=1(other)
bash-3.2$ gcc raptor_dtprintname_intel.c -o raptor_dtprintname_intel -Wall
bash-3.2$ ./raptor_dtprintname_intel 192.168.1.1:0
raptor_dtprintname_intel.c - dtprintinfo 0day, Solaris/Intel
Copyright (c) 2004-2019 Marco Ivaldi <raptor@0xdeadbeef.info>
Using SI_PLATFORM : i86pc (5.10)
Using stack base : 0x8047fff
Using rwx_mem address : 0xfeffa004
Using sc address : 0x8047f60
Using strcpy() address : 0xfefe26a0
lpstat called with -v
lpstat called with -v
lpstat called with -d
uid=0(root) gid=1(other)
3. Affected Platforms.
All platforms shipping the Common Desktop Environment are potentially
affected. This includes:
* Oracle Solaris 10 1/13 (Update 11) and earlier [default installation]
According to the CDE Wiki, the following platforms are officially supported:
* All Official Ubuntu variants 12.04 - 18.04
* Debian 6, 7, 8, 9
* Fedora 17 at least
* Archlinux
* Red Hat
* Slackware 14.0
* OpenBSD
* NetBSD
* FreeBSD 9.2, 10.x, 11.x
* openSUSE Tumbleweed (gcc7)
* openSUSE Leap 4.2 (gcc4)
* SUSE 12 SP3 (gcc4)
* Solaris, OpenIndiana
4. Fix.
The upstream CDE maintainers have issued a patch for this vulnerability. Oracle
is investigating the issue via tracking# S1153109 and is expected to release a
fix for all affected-supported versions of Solaris via their quarterly Critical
Patch Update (CPU) program.
As a temporary workaround, it is possible to remove the setuid bit from the
dtprintinfo executable as follows:
bash-3.2# chmod -s /usr/dt/bin/dtprintinfo
5. Proof of Concept.
A working exploit for Oracle Solaris 10 1/13 (Update 11) Intel has been
developed as a proof of concept. Exploits for other Solaris versions and for
the SPARC architecture are also available. All exploits can be downloaded at:
https://github.com/0xdea/raptor_infiltrate19/https://github.com/0xdea/exploits/
8<-----------------------------------------------------------
Chase