Bug 693002 – <app-text/ghostscript-gpl-9.28_rc4: multiple vulnerabilities (CVE-2019-{14811,14812,14813,14817})

• Status: RESOLVED FIXED
• Product: Gentoo Security

[Description Agostino Sarubbo 2019-08-28 12:51:31 UTC]

From ${URL} :

This is to report another 4 CVEs in ghostscript, rated important. They are all similar to the recently reported CVE-2019-10216 (reference to `.forceput` can be accessed)

Ghostscript is a suite of software providing an interpreter for Adobe Systems' PostScript (PS) and Portable Document Format (PDF) page description languages.  Its primary purpose includes displaying (rasterization & rendering) and printing of document pages, as well as conversions between different document formats.
URL : www.ghostscript.com

1- CVE-2019-14811 : Safer Mode Bypass by .forceput Exposure in .pdf_hook_DSC_Creator (701445)

2- CVE-2019-14812 : Safer Mode Bypass by .forceput Exposure in setuserparams (701444)

3- CVE-2019-14813 : Safer Mode Bypass by .forceput Exposure in setsystemparams (701443)

4- CVE-2019-14817 : Safer Mode Bypass by .forceput Exposure in .pdfexectoken and other procedures (701450)

In each case, a specially crafted script could get a reference to .forceput and use that to disable the -dSAFER protection. This then allows the script to access file system outside of resitricted areas and execute arbitrary commands.
Regarding CVE-2019-14817, only the .pdfexectoken procedure was proven to be vulnerable, the other fixed methods were only potentially vulnerable.

Preventing the modification of the error handler might protect most of these vulnerable functions

The fixes have been pushed upstream :

CVE-2019-14811, CVE-2019-14812, CVE-2019-14813 : 
http://git.ghostscript.com/?p=ghostpdl.git;a=commitdiff;h=885444fcbe10dc42787ecb76686c8ee4dd33bf33

CVE-2019-14817 : 
http://git.ghostscript.com/?p=ghostpdl.git;a=commitdiff;h=cd1b1cacadac2479e291efe611979bdc1b3bdb19

Acknowledgments :
CVE-2019-14811, CVE-2019-14812, CVE-2019-14813 were reported to upstream by Hiroki MATSUKUMA of Cyber Defense Institute, Inc.


Noteworthy (similar to CVE-2019-10216) :
A recent modification, started in upstream commit 7ecbfda92b4c8dbf6f6c2bf8fc82020a29219eff, changed the access to file permissions. After this commit, the ability to modify the /PermitFile* entries from systemdict's /userparams entry should have no effect.
That is to say: getting a reference to highly privileged function (such as .forceput), can still be used to remove SAFER, and modify the /PermitFile* lists. However, the interpreter will still refuse to access files outside of a list provided from a set of command line options. This should mitigate the class of ghostscript vulnerabilities similar to the one described above.



@maintainer(s): after the bump, in case we need to stabilize the package, please let us know if it is ready for the stabilization or not.

[Comment 1 Agostino Sarubbo 2019-08-28 12:53:03 UTC]

I guess that 2.28 will have the fixes. In the meantime, the latest releases also contain fixes for security issues discovered from fuzzing.

[Comment 2 Larry the Git Cow 2019-10-07 00:35:42 UTC]

The bug has been referenced in the following commit(s):

https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=215d56f50a764294df20c6a378fbe9b709fe056d

commit 215d56f50a764294df20c6a378fbe9b709fe056d
Author:     Thomas Deutschmann <[e-mail]>
AuthorDate: 2019-10-07 00:35:05 +0000
Commit:     Thomas Deutschmann <[e-mail]>
CommitDate: 2019-10-07 00:35:23 +0000

    app-text/ghostscript-gpl: bump to v9.28rc4
    
    Bug: https://bugs.gentoo.org/693002
    Package-Manager: Portage-2.3.76, Repoman-2.3.17
    Signed-off-by: Thomas Deutschmann <[e-mail]>

 app-text/ghostscript-gpl/Manifest                  |   2 +
 .../ghostscript-gpl-9.28_rc4.ebuild                | 200 +++++++++++++++++++++
 2 files changed, 202 insertions(+)

[Comment 3 Arfrever Frehtes Taifersar Arahesis 2019-10-24 01:33:13 UTC]

Ghostscript 9.50 was released on 2019-10-15:
https://ghostscript.com/pipermail/gs-devel/2019-October/010232.html

"""
The more astute among you might notice that 9.28 has morphed into 9.50.
In a recent discussion amongst the Ghostscript developers, it became
clear that the redesign and reimplementation of the file security
features warranted more recognition than just the usual single digit
version increment. Hence we opted to bump it up to 9.50.
"""

[Comment 4 Arfrever Frehtes Taifersar Arahesis 2019-10-24 23:36:41 UTC]

https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=afdbdbedba9222816f18bbf03d102bdb73ce3a15

commit afdbdbedba9222816f18bbf03d102bdb73ce3a15
Author:     Thomas Deutschmann <[e-mail]>
AuthorDate: 2019-10-24 22:18:04 +0000
Commit:     Thomas Deutschmann <[e-mail]>
CommitDate: 2019-10-24 22:29:05 +0000

    app-text/ghostscript-gpl: bump to v9.50
    
    Package-Manager: Portage-2.3.78, Repoman-2.3.17
    Signed-off-by: Thomas Deutschmann <[e-mail]>

[Comment 5 Agostino Sarubbo 2019-10-25 15:14:16 UTC]

sparc stable

[Comment 6 Agostino Sarubbo 2019-10-25 15:14:59 UTC]

ppc stable

[Comment 7 Agostino Sarubbo 2019-10-25 15:15:35 UTC]

x86 stable

[Comment 8 Agostino Sarubbo 2019-10-26 15:16:17 UTC]

amd64 stable

[Comment 9 Rolf Eike Beer 2019-10-27 19:27:17 UTC]

hppa stable

[Comment 10 Agostino Sarubbo 2019-10-28 07:43:29 UTC]

ppc64 stable

[Comment 11 Mikle Kolyada (RETIRED) 2019-11-01 10:32:13 UTC]

arm stable

[Comment 12 Aaron Bauman (RETIRED) 2019-11-06 23:58:31 UTC]

arm64 stable

[Comment 13 Mikle Kolyada (RETIRED) 2019-11-08 08:34:02 UTC]

s390 stable

[Comment 14 Agostino Sarubbo 2019-11-13 13:17:17 UTC]

ia64 stable

[Comment 15 Matt Turner 2019-11-17 07:21:52 UTC]

alpha stable

all arches stable

[Comment 16 Sam James 2020-03-19 01:32:40 UTC]

@maintainer(s), ok to cleanup?

[Comment 17 Sam James 2020-03-28 21:55:42 UTC]

Tree is clean: https://bugs.gentoo.org/676264#c16

[Comment 18 Thomas Deutschmann (RETIRED) 2020-04-01 19:46:38 UTC]

Added to an existing GLSA request.

[Comment 19 GLSAMaker/CVETool Bot 2020-04-01 19:53:27 UTC]

This issue was resolved and addressed in
 GLSA 202004-03 at https://security.gentoo.org/glsa/202004-03
by GLSA coordinator Thomas Deutschmann (whissi).