[PATCH] ghostscript: CVE-2019-14869

[PATCH] ghostscript: CVE-2019-14869

[Stefan Ghinea]

A flaw was found in all versions of ghostscript 9.x before 9.28,
where the `.charkeys` procedure, where it did not properly secure
its privileged calls, enabling scripts to bypass `-dSAFER` restrictions.
An attacker could abuse this flaw by creating a specially crafted
PostScript file that could escalate privileges within the Ghostscript
and access files outside of restricted areas or execute commands.

References:
https://nvd.nist.gov/vuln/detail/CVE-2019-14869

Upstream patches:
https://git.ghostscript.com/?p=ghostpdl.git;a=commitdiff;h=485904

Signed-off-by: Stefan Ghinea <stefan.ghinea@windriver.com>
---
 .../ghostscript/CVE-2019-14869-0001.patch     | 70 +++++++++++++++++++
 .../ghostscript/ghostscript_9.27.bb           |  2 +
 2 files changed, 72 insertions(+)
 create mode 100644 meta/recipes-extended/ghostscript/ghostscript/CVE-2019-14869-0001.patch

diff --git a/meta/recipes-extended/ghostscript/ghostscript/CVE-2019-14869-0001.patch b/meta/recipes-extended/ghostscript/ghostscript/CVE-2019-14869-0001.patch
new file mode 100644
index 0000000000..715ec1c450
--- /dev/null
+++ b/meta/recipes-extended/ghostscript/ghostscript/CVE-2019-14869-0001.patch
@@ -0,0 +1,70 @@
+From 485904772c5f0aa1140032746e5a0abfc40f4cef Mon Sep 17 00:00:00 2001
+From: Chris Liddell <chris.liddell@artifex.com>
+Date: Tue, 5 Nov 2019 09:45:27 +0000
+Subject: [PATCH] Bug 701841: remove .forceput from /.charkeys
+
+When loading Type 1 or Truetype fonts from disk, we attempt to extend the glyph
+name table to include all identifiable glyph names from the Adobe Glyph List.
+
+In the case of Type 1 fonts, the font itself (almost always) marks the
+CharStrings dictionary as read-only, hence we have to use .forceput for that
+case.
+
+But for Truetype fonts, the CharStrings dictionary is created internally and is
+not read-only until *after* we have fully populated it (including the extended
+glyph names from the AGL), hence there is no need for .forceput, and no need to
+carry the security risk of using it.
+
+Replace with regular put.
+
+CVE: CVE-2019-14869
+Upstream-Status: Backport [git://git.ghostscript.com/ghostpdl.git]
+
+Signed-off-by: Stefan Ghinea <stefan.ghinea@windriver.com>
+---
+ Resource/Init/gs_ttf.ps | 8 ++++----
+ 1 file changed, 4 insertions(+), 4 deletions(-)
+
+diff --git a/Resource/Init/gs_ttf.ps b/Resource/Init/gs_ttf.ps
+index e34967d..5354ff0 100644
+--- a/Resource/Init/gs_ttf.ps
++++ b/Resource/Init/gs_ttf.ps
+@@ -1301,7 +1301,7 @@ currentdict /.pickcmap_with_no_xlatmap .undef
+           TTFDEBUG { (\n1 setting alias: ) print dup ==only
+                 ( to be the same as  ) print 2 index //== exec } if
+ 
+-          7 index 2 index 3 -1 roll exch .forceput
++          7 index 2 index 3 -1 roll exch put
+         } forall
+         pop pop pop
+       }
+@@ -1319,7 +1319,7 @@ currentdict /.pickcmap_with_no_xlatmap .undef
+           exch pop
+           TTFDEBUG { (\n2 setting alias: ) print 1 index ==only
+                      ( to use glyph index: ) print dup //== exec } if
+-          5 index 3 1 roll .forceput
++          5 index 3 1 roll put
+           //false
+         }
+         {
+@@ -1336,7 +1336,7 @@ currentdict /.pickcmap_with_no_xlatmap .undef
+         {                            %  CharStrings(dict) isunicode(boolean) cmap(dict) RAGL(dict) gname(name) codep(integer) gindex(integer)
+           TTFDEBUG { (\3 nsetting alias: ) print 1 index ==only
+                 ( to be index: ) print dup //== exec } if
+-          exch pop 5 index 3 1 roll .forceput
++          exch pop 5 index 3 1 roll put
+         }
+         {
+           pop pop
+@@ -1366,7 +1366,7 @@ currentdict /.pickcmap_with_no_xlatmap .undef
+       } ifelse
+     ]
+   TTFDEBUG { (Encoding: ) print dup === flush } if
+-} .bind executeonly odef		% hides .forceput
++} .bind odef
+ 
+ % ---------------- CIDFontType 2 font loading ---------------- %
+ 
+-- 
+2.20.1
+
diff --git a/meta/recipes-extended/ghostscript/ghostscript_9.27.bb b/meta/recipes-extended/ghostscript/ghostscript_9.27.bb
index 9e1f3e2f49..a7eab5e603 100644
--- a/meta/recipes-extended/ghostscript/ghostscript_9.27.bb
+++ b/meta/recipes-extended/ghostscript/ghostscript_9.27.bb
@@ -28,6 +28,8 @@ SRC_URI_BASE = "https://github.com/ArtifexSoftware/ghostpdl-downloads/releases/d
                 file://CVE-2019-14811-0001.patch \
                 file://CVE-2019-14817-0001.patch \
                 file://CVE-2019-14817-0002.patch \
+                file://CVE-2019-14869-0001.patch \
+
 "
 
 SRC_URI = "${SRC_URI_BASE} \
-- 
2.20.1

Re: [PATCH] ghostscript: CVE-2019-14869

[Ross Burton]

On 21/11/2019 15:28, Stefan Ghinea wrote:
>                   file://CVE-2019-14811-0001.patch \
>                   file://CVE-2019-14817-0001.patch \
>                   file://CVE-2019-14817-0002.patch \
> +                file://CVE-2019-14869-0001.patch \
> +
>   "


Parsing recipes...ERROR: ParseError at 
/home/pokybuild/yocto-worker/qemux86-64/build/meta/recipes-extended/ghostscript/ghostscript_9.27.bb:32: 
unparsed line: 'SRC_URI_BASE = 
"https://github.com/ArtifexSoftware/ghostpdl-downloads/releases/download/gs927/${BPN}-${PV}.tar.gz 
                 file://ghostscript-9.15-parallel-make.patch 
     file://ghostscript-9.16-Werror-return-type.patch 
file://do-not-check-local-libpng-source.patch 
file://avoid-host-contamination.patch 
file://mkdir-p.patch                 file://CVE-2019-14811-0001.patch 
              file://CVE-2019-14817-0001.patch 
file://CVE-2019-14817-0002.patch 
file://CVE-2019-14869-0001.patch '

Please remember to test your patches.

Ross