[Bug 1785499] Re: Make squashfs-tools in Xenial in sync with Bionic and Cosmic

[Stéphane Graber]

== fix 2GB limit in mksquashfs ==
=== Rationale ===
I don't have a direct use for this patch, but it seemed simpler and easier to just sync the entire stack of bugfixes with what we have in bionic and cosmic, so including this one too.


This fixes the case where a user attempts to append to a squashfs larger that's larger than 2GB.

=== Test case ===
Generate a large squashfs, easiest to achieve it is to turn off most compression options and feed it a large random file. Size should exceed 2GB.

Run mksquashfs with some random extra data to append and the pre-
generated big squashfs.

Prior to this fix, you should get a failure like "Lseek on destination
failed: Invalid argument".

With the fix applied, mksquashfs should just append the data and the
resulting squashfs should be mountable and contain the new data.


=== Regression potential ===
This is another very small patch that looks "obviously correct" in that squashfs was simply overflowing an int in this case. The fix switches the type to "off_t" avoiding this issue.

The same fix has been in Ubuntu and Debian for a while so has seen a
good amount of exposure.

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to squashfs-tools in Ubuntu.
https://bugs.launchpad.net/bugs/1785499

Title:
  Make squashfs-tools in Xenial in sync with Bionic and Cosmic

Status in squashfs-tools package in Ubuntu:
  Fix Released
Status in squashfs-tools source package in Xenial:
  Triaged

Bug description:
  squashfs-tools upstream hasn't changed in a while but a number of
  bugfixes are applied through packaging in Debian and Ubuntu.

  The bionic and cosmic versions right now are identical but xenial is
  missing a few fixes which is a problem for the LXD snap among other
  things.

  Looking at debian/series/patches, the fixes currently missing in the xenial version are:
   - 0007-fix-2GB-limit-in-mksquashfs.patch
   - 0008-preserve_file_capabilities.patch

  I'll attach test cases for both of those below and then will prepare
  an SRU that effectively makes the source package identical to what we
  have in bionic, minus the different changelog.

  This should be pretty safe considering both Ubuntu and Debian have
  been shipping those two patches for a while and the fs caps one is
  going to be pretty important moving forward as we're discussing having
  Ubuntu ship with fscaps by default.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/squashfs-tools/+bug/1785499/+subscriptions