Bug#976102: a2ps 32-bit segfaults on startup

[Bernhard Übelacker <bernhardu@mailbox.org>]

Am 15.12.20 um 23:00 schrieb Mack Stanley:
> Dear Bernhard,
>
> Thanks so much for your interest and your message.  I very recently 
> realized that my bug report is in error and hoped that I would be able 
> to correct or withdraw it before troubling anyone.
>
> Here is how to reproduce the segfault I observed (in wither 32 or 64 bit 
> debian a2ps):
>
> Near the top of /etc/a2ps-site.cfg comment out one or both of the lines
> _____
>
> Options: --encoding=latin1
> Options: --medium=libpaper
> _____
>
> Then just execute
>
> a2ps
>
> The result will be a crash with simply
>
> Segmentation Fault
>
> -------
>
> I am very sorry to have filed a false bug report.  I had tried two 32 
> bit installations and one 64 bit.  Evidently I made the same mistake in 
> both 32 bit installations: I must have installed with an old Fedora 
> a2ps-site.cfg already in /etc/ , which the Debian installation politely 
> refused to overwrite.  The default Fedora a2ps-site.cfg  has those two 
> lines as
>
> #Options: --encoding=latin1
> Options: --medium=_glibc
>
> After removing "#" from the first line, the debian build a2ps complains 
> helpfully about the second line.  But with the "#" it just segfaults.
>
> I am sorry it took me so long to find this mistake.  It wasn't till I 
> built 32 bit a2ps from the GNU source that I saw the problem 
> (http://ftp.gnu.org/gnu/a2ps/a2ps-4.14.tar.gz./configure --prefix=/usr 
> --with-gnu-gettext --with-medium=letter ).
>
> It would be nice if a2ps itself had been more forthcoming about my 
> mistake rather than segfaulting.  But it was just that---my mistake.
>
> Again, my apologies for wasting your time and my thanks for your interest.
>
> Best regards, Mack



Hello Mack,
no problem, with these great details I could collect these backtraces:


    # With: #Options: --encoding=latin1

    (gdb) bt
    #0  __strlen_sse2_bsf () at ../sysdeps/i386/i686/multiarch/strlen-sse2-bsf.S:50
    #1  0x0050bfcc in strlower (string=0x0) at routines.c:95
    #2  0x005096cd in get_encoding_by_alias (job=0x57bc50, alias=0x0) at encoding.c:1207
    #3  0x0050aa50 in a2ps_job_finalize (job=0x57bc50) at jobs.c:305
    #4  0x004ef980 in main (argc=<optimized out>, argv=<optimized out>) at main.c:1025
    (gdb)


    # With: #Options: --medium=libpaper

    (gdb) bt
    #0  __strcasecmp_l_sse4_2 () at ../sysdeps/i386/i686/multiarch/strcmp-sse4.S:229
    #1  0x0050e22a in a2ps_get_medium (job=0xb1ec50, name=0x0) at media.c:164
    #2  0x0050ea6c in a2ps_job_finalize (job=0xb1ec50) at jobs.c:312
    #3  0x004f3980 in main (argc=<optimized out>, argv=<optimized out>) at main.c:1025
    (gdb)


As you mentioned some relation to fedora I made a short
search and it looks like there are some patches used,
which are not yet upstreamed.

    https://src.fedoraproject.org/rpms/a2ps/tree/
    https://git.savannah.gnu.org/cgit/a2ps.git/log/

Especially the a2ps-4.13b-encoding.patch and
a2ps-4.13-glibcpaper.patch seem related.

Kind regards,
Bernhard



apt install systemd-coredump gdb a2ps a2ps-dbgsym
zcat /usr/share/doc/a2ps/README.gz | a2ps
coredumpctl list
coredumpctl gdb 2478

https://sources.debian.org/src/a2ps/1:4.14-5/lib/jobs.c/#L305