Bug#1084021: regression in 2.4.2-3+deb12u8: client hangs retrieving printer information

[Thorsten Alteholz <debian@alteholz.de>]

    Hi Marcin,

On 04.10.24 13:52, Marcin Owsiany wrote:

Indeed, on host B the following appears at the same time the print dialog hangs in evince ("piec" is host A):

E [04/Oct/2024:13:29:44 +0200] HP_Smart_Tank_710_720_series_piec: Printer returned invalid data: \"media-supported\": Bad keyword value \"\" - invalid character (RFC 8011 section 5.1.4).

    yes, this message belongs to the new validation of attributes that
    was part of the latest patches.
    Unfortunately this printer does not behave correct, so I think this
    is rather a feature than a bug.

FWIW, I did "sudo grep -R media-supported /etc 2>/dev/null" and that came back with nothing. So I guess it's a bug in the printer's firmware? Can I work this around somehow on the cups side?

    yes, this is a bug in the printer's firmware.  cups asks the printer
    about some properties and one of the answers contains a non
    RFC-conform character. Other such characters resulted in an RCE, so
    this check is somewhat important. If there is no other firmware
    available, I am afraid you have to build your own cups package.
    The culprit is in 0024-CVE-2024-47175-and-further-hardening.patch
      for scheduler/ipp.c
      
        Thorsten