** Description changed:

  (Perhaps this should be reported at Ubuntu 26.10 instead?)
  
  After upgrading to Ubuntu 26.10 (GNOME 51), Nautilus showed PDF thumbnails
  only for files with an embedded thumbnail. All other PDFs got the generic 
icon.
  
  The cause was a leftover evince package, version 49~alpha-2ubuntu3, from an
  earlier release. It was not upgraded or removed during the upgrade, so both
  evince.thumbnailer and papers.thumbnailer were registered for application/pdf.
  gnome-desktop picks between them in no defined order, and here 
evince-thumbnailer
  was used.
  
+ The evince 49~alpha package dates from Ubuntu 25.10 (GNOME 49), when Papers
+ replaced Evince as the default. Upgrade path on this machine:
+ 25.10 -> 26.04 -> 26.10. The obsolete package survived both upgrades. Both 
upgrades have been quite early, so it could be that which triggered the problem.
+ 
  evince-thumbnailer now uses glycin, which runs its loaders under bwrap. The
  AppArmor profile /usr/bin/evince-thumbnailer from this old package does not
  allow that. Denials seen:
  
  ```
-   apparmor="DENIED" operation="exec" profile="/usr/bin/evince-thumbnailer" 
name="/usr/bin/bwrap" comm="blocking-1" requested_mask="x"
-   apparmor="DENIED" operation="file_perm" class="net" 
profile="/usr/bin/evince-thumbnailer" family="unix" sock_type="seqpacket" 
peer="bwrap"
-   apparmor="DENIED" operation="file_perm" class="net" 
profile="/usr/bin/evince-thumbnailer" family="unix" sock_type="seqpacket" 
peer="unpriv_bwrap"
+   apparmor="DENIED" operation="exec" profile="/usr/bin/evince-thumbnailer" 
name="/usr/bin/bwrap" comm="blocking-1" requested_mask="x"
+   apparmor="DENIED" operation="file_perm" class="net" 
profile="/usr/bin/evince-thumbnailer" family="unix" sock_type="seqpacket" 
peer="bwrap"
+   apparmor="DENIED" operation="file_perm" class="net" 
profile="/usr/bin/evince-thumbnailer" family="unix" sock_type="seqpacket" 
peer="unpriv_bwrap"
  ```
  
  After allowing bwrap via a local override, the next denial was:
  
  ```
-   apparmor="DENIED" operation="exec" profile="/usr/bin/evince-thumbnailer" 
name="/usr/libexec/glycin-loaders/2+/glycin-image-rs" comm="gly-hdl-editor" 
requested_mask="x"
+   apparmor="DENIED" operation="exec" profile="/usr/bin/evince-thumbnailer" 
name="/usr/libexec/glycin-loaders/2+/glycin-image-rs" comm="gly-hdl-editor" 
requested_mask="x"
  ```
  
  Putting the profile in complain mode made thumbnails appear, which confirms
  AppArmor as the cause.
  
  The current papers profile (/etc/apparmor.d/usr.bin.papers) already handles
  this through a bwrap_trans child profile stacked with bwrap and a glycin child
  profile. The old evince profile has nothing equivalent.
  
  Workaround: `sudo apt purge evince`. Nothing installed depended on it (only an
  Enhances from nautilus-sendto). After purging, papers-thumbnailer took over 
and
  works in enforce mode.
  
  Expected: on upgrade to 26.10, the obsolete evince 49~alpha package should be
  upgraded to a version whose AppArmor profile supports glycin, or removed or
  transitioned to papers.
  
  Versions:
-   Ubuntu 26.10, GNOME 51
-   evince 49~alpha-2ubuntu3 (now removed)
-   papers <version>
-   kernel.apparmor_restrict_unprivileged_userns = 1
+   Ubuntu 26.10, GNOME 51
+   evince 49~alpha-2ubuntu3 (now removed)
+   papers <version>
+   kernel.apparmor_restrict_unprivileged_userns = 1

-- 
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/2172692

Title:
  Leftover evince 49~alpha-2ubuntu3 after update to Ubuntu 26.10 blocks
  thumbnailing

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/evince/+bug/2172692/+subscriptions


-- 
ubuntu-bugs mailing list
[email protected]
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs

Reply via email to