Re: Why does PDFPIC require unsafe mode -U, but PSPIC doesn't?

[Deri]

On Sunday, 30 July 2023 16:43:28 BST Michał Kruszewski wrote:
> I do not have much knowledge in this area.
> I just came across this interesting blog
> https://cromwell-intl.com/open-source/pdf-not-authorized.html that also has
> some nice references.
> 
> However, right now I wonder when I should be extra careful when using groff.
> -Tpdf is my default choice, and most of my papers include images, so I use
> -U almost all the time.
> 
> Best regards,
> Michał Kruszewski
> 
> Sent with Proton Mail secure email.

Hi Michał,

You are safe. -Tpdf does not use ghostscript at all. Also the pdfs it produces 
contain no raw postscript, the article wrongly conflates PDF and PostScript as 
the same. I believe the bug involves the 'grestore' command which is a 
postscript operator. 

The bug is 5 years old and has been fixed since version 9.25:-

https://ubuntu.com/security/CVE-2018-16802

Which also makes it clear that it is crafted postscript which triggered the 
bug.

Cheers

Deri