Subject: [bug#32181] [PATCH] gnu: ghostscript: Fix CVE-2018-10194.

From: Kei Kebreau <[email-masked]>
Date: Tue, 17 Jul 2018 11:32:03 -0400

Leo Famulari <[email-masked]> writes:

> * gnu/packages/ghostscript.scm (ghostscript)[replacement]: New field.
> (ghostscript/fixed): New variable.
> * gnu/packages/patches/ghostscript-CVE-2018-10194.patch: New file.
> * gnu/local.mk (dist_patch_DATA): Add it.
> ---
>  gnu/local.mk                                  |  1 +
>  gnu/packages/ghostscript.scm                  | 11 ++++
>  .../patches/ghostscript-CVE-2018-10194.patch  | 52 +++++++++++++++++++
>  3 files changed, 64 insertions(+)
>  create mode 100644 gnu/packages/patches/ghostscript-CVE-2018-10194.patch
>
> diff --git a/gnu/local.mk b/gnu/local.mk
> index d40b1963d..20a7d17e7 100644
> --- a/gnu/local.mk
> +++ b/gnu/local.mk
> @@ -713,6 +713,7 @@ dist_patch_DATA =						\
>    %D%/packages/patches/geoclue-config.patch			\
>    %D%/packages/patches/ghc-8.0-fall-back-to-madv_dontneed.patch \
>    %D%/packages/patches/ghc-dont-pass-linker-flags-via-response-files.patch	\
> +  %D%/packages/patches/ghostscript-CVE-2018-10194.patch		\
>    %D%/packages/patches/ghostscript-no-header-id.patch		\
>    %D%/packages/patches/ghostscript-no-header-uuid.patch		\
>    %D%/packages/patches/ghostscript-no-header-creationdate.patch \
> diff --git a/gnu/packages/ghostscript.scm b/gnu/packages/ghostscript.scm
> index 0a6043ba6..1240b1dc1 100644
> --- a/gnu/packages/ghostscript.scm
> +++ b/gnu/packages/ghostscript.scm
> @@ -132,6 +132,7 @@ printing, and psresize, for adjusting page sizes.")
>  (define-public ghostscript
>    (package
>      (name "ghostscript")
> +    (replacement ghostscript/fixed)
>      (version "9.23")
>      (source
>        (origin
> @@ -250,6 +251,16 @@ output file formats and printers.")
>      (home-page "https://www.ghostscript.com/")
>      (license license:agpl3+)))
>  
> +(define-public ghostscript/fixed
> +  (hidden-package
> +    (package
> +      (inherit ghostscript)
> +      (source
> +        (origin
> +          (inherit (package-source ghostscript))
> +          (patches (append (origin-patches (package-source ghostscript))
> +                           (search-patches "ghostscript-CVE-2018-10194.patch"))))))))
> +
>  (define-public ghostscript/x
>    (package/inherit ghostscript
>      (name (string-append (package-name ghostscript) "-with-x"))
> diff --git a/gnu/packages/patches/ghostscript-CVE-2018-10194.patch b/gnu/packages/patches/ghostscript-CVE-2018-10194.patch
> new file mode 100644
> index 000000000..242e57c27
> --- /dev/null
> +++ b/gnu/packages/patches/ghostscript-CVE-2018-10194.patch
> @@ -0,0 +1,52 @@
> +Fix CVE-2018-10194:
> +
> +https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-10194
> +https://bugs.ghostscript.com/show_bug.cgi?id=699255
> +
> +Patch copied from upstream source repository:
> +
> +https://git.ghostscript.com/?p=ghostpdl.git;a=commit;h=39b1e54b2968620723bf32e96764c88797714879
> +
> +From 39b1e54b2968620723bf32e96764c88797714879 Mon Sep 17 00:00:00 2001
> +From: Ken Sharp <[email-masked]>
> +Date: Wed, 18 Apr 2018 15:46:32 +0100
> +Subject: [PATCH] pdfwrite - Guard against trying to output an infinite number
> +
> +Bug #699255 " Buffer overflow on pprintg1 due to mishandle postscript file data to pdf"
> +
> +The file uses an enormous parameter to xyxhow, causing an overflow in
> +the calculation of text positioning (value > 1e39).
> +
> +Since this is basically a nonsense value, and PostScript only supports
> +real values up to 1e38, this patch follows the same approach as for
> +a degenerate CTM, and treats it as 0.
> +
> +Adobe Acrobat Distiller throws a limitcheck error, so we could do that
> +instead if this approach proves to be a problem.
> +---
> + devices/vector/gdevpdts.c | 7 ++++++-
> + 1 file changed, 6 insertions(+), 1 deletion(-)
> +
> +diff --git a/devices/vector/gdevpdts.c b/devices/vector/gdevpdts.c
> +index 848ad781f..172fe6bc3 100644
> +--- a/devices/vector/gdevpdts.c
> ++++ b/devices/vector/gdevpdts.c
> +@@ -103,9 +103,14 @@ append_text_move(pdf_text_state_t *pts, double dw)
> + static int
> + set_text_distance(gs_point *pdist, double dx, double dy, const gs_matrix *pmat)
> + {
> +-    int code = gs_distance_transform_inverse(dx, dy, pmat, pdist);
> ++    int code;
> +     double rounded;
> + 
> ++    if (dx > 1e38 || dy > 1e38)
> ++        code = gs_error_undefinedresult;
> ++    else
> ++        code = gs_distance_transform_inverse(dx, dy, pmat, pdist);
> ++
> +     if (code == gs_error_undefinedresult) {
> +         /* The CTM is degenerate.
> +            Can't know the distance in user space.
> +-- 
> +2.18.0
> +

I haven't built any dependent packages with this yet, but it builds
properly on its own.