Bug#909076: ghostscript: ps2ascii crashes: Error: /typecheck in --.bind--

[Salvatore Bonaccorso]

hi,

On Tue, Sep 18, 2018 at 09:58:10AM +0200, Mattia Rizzolo wrote:
> Package: ghostscript
> Version: 9.20~dfsg-3.2+deb9u5
> Severity: serious
> X-Debbugs-CC: team at security.debian.org, Moritz Mühlenhoff <jmm at debian.org>, reproducible-builds at lists.alioth.debian.org
> Control: affects -1 diffoscope
> 
> Dear maintainer,
> 
> after the latest ghostscript security update, ps2ascii started to crash:
> 
> |% ps2ascii /build/diffoscope-101~bpo9+1/.pybuild/pythonX.Y_3.5/build/tests/data/test1.ps
> |Error: /typecheck in --.bind--
> |Operand stack:
> |   --nostringval--   false   setshared   true   --dict:30/32(L)--   typecheck   --nostringval--   currentglobal   .currentglobal
> |Execution stack:
> |   %interp_exit   .runexec2   --nostringval--   --nostringval--   --nostringval--   2   %stopped_push   --nostringval--   --nostringval--   --nostringval--   false   1   %stopped_push   1998   2   3   %oparray_pop   1997   2   3   %oparray_pop   1981   2   3   %oparray_pop   1868   2   3   %oparray_pop   --nostringval--   %errorexec_pop   .runexec2   --nostringval--   --nostringval--   --nostringval--   2   %stopped_push   --nostringval--   2009   3   3   %oparray_pop   --nostringval--   --nostringval--   --dict:1267/1684(G)--   --nostringval--   1936   %dict_continue   --nostringval--   1974   9   4   %oparray_pop   --nostringval--
> |Dictionary stack:
> |   --dict:1267/1684(G)--   --dict:0/20(G)--   --dict:81/200(L)--   --dict:1267/1684(G)--
> |Current allocation mode is global
> |Current file position is 44643
> |GPL Ghostscript 9.20: Unrecoverable error, exit code 1
> 
> 
> Downgrading to 9.20~dfsg-3.2+deb9u4 shows the problem is limited to the
> latest update:
> 
> |% ps2ascii /build/diffoscope-101~bpo9+1/.pybuild/pythonX.Y_3.5/build/tests/data/test1.ps
> |
> |
> |Today's date: February 28, 2016
> |
> |1
> 
> 
> This also causes diffoscope (both 78 in stretch and whatever is in
> stretch-backports at the moment) to FTBFS.

Some updates:

The issue is triggered by the
025_fb713b3818b52d8a6cf62c951eba2e1795ff9624.patch patch, which is
http://git.ghostscript.com/?p=ghostpdl.git;a=commit;h=fb713b3818b52d8a6cf62c951eba2e1795ff9624
. 

Ghostscript built from git on fb713b3818b52d8a6cf62c951eba2e1795ff9624
does not seem to tigger the same problem, so if this is correct, we
might miss a prerequisite to fb713b3818b52d8a6cf62c951eba2e1795ff9624
.

Regards,
Salvatore