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[Bug 1156398] Re: "scp-dbus-service" creates 100s of thousands symlinks to the ppd-file in "/tmp" untill the root filesystem runs out of inodes everytime I print something


I installed system-config-printer-
udev_1.5.1+20141010-0ubuntu2.1_amd64.deb and rebooted the system but I
still have this bug. For me it's not solved.

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  "scp-dbus-service" creates 100s of thousands symlinks to the ppd-file
  in "/tmp" untill the root filesystem runs out of inodes everytime I
  print something

Status in “system-config-printer” package in Ubuntu:
  Fix Released
Status in “system-config-printer” source package in Utopic:
  Fix Committed
Status in “system-config-printer” package in Debian:
  Fix Released

Bug description:
  When I print e.g. a webpage in Firefox, shortly after the printing finished, the root filesystem is running out of available inodes.
  "/tmp/" is populated with hundreds of thousands of symlinks to "/etc/cups/ppd/Hewlett-Packard-hp-LaserJet-4350.ppd" which are all named like "51465xxxxxxxx" (where x is a hexadecimal digit) and are created at a rate of aprox. 1500 new symlinks per second. The filenames are not counted up but seem to appear in random order.

  During this time the process "/usr/bin/python /usr/share/system-
  config-printer/scp-dbus-service.py" is using ~130% CPU.

  As soon as I kill this process, no more symlinks are created.
  When I wait for the inodes to run out, this process's CPU usage drops to ~7% for a few seconds before the process suddenly disapears from the process list. This indicates that all the symlinks are created by this one process.

  If I delete the symlinks now and print another document, things start
  over again.

  ---+ Furher notes
  This does not happen when printing with

  It does happen when printing with

  An unpriviledged user could break down the system by filling up all
  free inodes on the root fs, so this might be security relevant.


  On an attempt to print out of an application like for example Firefox
  a process runs crazy and does nothing than creating links in /tmp
  until the file system runs out of inodes. If the /tmp directory is on
  the root partition (and not a RAM disk) the system cannot create files
  any more and on the next boot it can take hours for the system to
  clean up, making the impression that the system is not able to boot
  any more.

  [Test Case]

  WARNING: To get your system easily back into a usable state by a
  siumple reboot, at first configure /tmp to be on a RAM disk.

  Modify the permissions of the PPD file of your print queue to remove
  the world-readable bit:

  sudo chmod o-r /etc/cups/ppd/*.ppd

  Then try to print from Firefox (or another desktop application). Run
  the "top" command and observe, scp-dbus-service will pick up 100% CPU.
  /tmp will fill up with links quickly.

  Kill the scp-dbus-service process to stop this. A quick workaround is
  removing the executable bit of scp-dbus-service.py but this will
  disable functionality of system-config-printer and other printer setup

  With the proposed package this will not happen any more. No mass
  creation of symlinks in /tmp and no CPU hogging by scp-dbus-service.

  [Regression Potential]

  Lo, the patch is rather simple, erroring out correctly when the PPD
  file is not readable to avoid an infinite loop.

  ProblemType: Bug
  DistroRelease: Ubuntu 12.10
  Package: system-config-printer-common 1.3.11+20120807-0ubuntu10
  ProcVersionSignature: Ubuntu 3.5.0-25.39-generic
  Uname: Linux 3.5.0-25-generic x86_64
  NonfreeKernelModules: openafs fglrx
  ApportVersion: 2.6.1-0ubuntu10
  Architecture: amd64
  Date: Mon Mar 18 00:45:56 2013
  Lpstat: Error: command ['lpstat', '-v'] failed with exit code 1: lpstat: Transport endpoint is not connected
  MachineType: Gigabyte Technology Co., Ltd. GA-A75M-UD2H
  MarkForUpload: True
  PackageArchitecture: all
  Papersize: letter
  PpdFiles: Hewlett-Packard-hp-LaserJet-4350: HP LaserJet 4350 pcl3, hpcups 3.12.2
  ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.5.0-25-generic root=/dev/mapper/hostname-root ro splash quiet vt.handoff=7
  SourcePackage: system-config-printer
  UpgradeStatus: No upgrade log present (probably fresh install)
  dmi.bios.date: 11/03/2011
  dmi.bios.vendor: Award Software International, Inc.
  dmi.bios.version: F5
  dmi.board.name: GA-A75M-UD2H
  dmi.board.vendor: Gigabyte Technology Co., Ltd.
  dmi.chassis.type: 3
  dmi.chassis.vendor: Gigabyte Technology Co., Ltd.
  dmi.modalias: dmi:bvnAwardSoftwareInternational,Inc.:bvrF5:bd11/03/2011:svnGigabyteTechnologyCo.,Ltd.:pnGA-A75M-UD2H:pvr:rvnGigabyteTechnologyCo.,Ltd.:rnGA-A75M-UD2H:rvr:cvnGigabyteTechnologyCo.,Ltd.:ct3:cvr:
  dmi.product.name: GA-A75M-UD2H
  dmi.sys.vendor: Gigabyte Technology Co., Ltd.

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