[Bug 1843479] Update Released

[Łukasz Zemczak]

The verification of the Stable Release Update for gzip has completed
successfully and the package is now being released to -updates.
Subsequently, the Ubuntu Stable Release Updates Team is being
unsubscribed and will not receive messages about this bug report.  In
the event that you encounter a regression using the package from
-updates please report a new bug using ubuntu-bug and tag the bug report
regression-update so we can easily find any regressions.

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https://bugs.launchpad.net/bugs/1843479

Title:
  gzip in Ubuntu Eoan results in Exec format error on WSL1

Status in binutils:
  Confirmed
Status in binutils package in Ubuntu:
  Fix Released
Status in gzip package in Ubuntu:
  Fix Released
Status in binutils source package in Eoan:
  Fix Committed
Status in gzip source package in Eoan:
  Fix Released

Bug description:
  IMPORTANT: Binutils was accidentally built in -proposed instead of in
  a PPA. I'm rebuilding it in https://launchpad.net/~ci-train-ppa-
  service/+archive/ubuntu/3876 for the -security pocket.

  [Impact]

   * Running gzip on WSL1 results in the following error:
     $ gzip
     -bash: /bin/gzip: cannot execute binary file: Exec format error
   * The error occurs frequently in package updates and makes gzip inoperable on WSL1
   * The problem is caused by PT_LOAD offset pointing past the end of file and the fix is fixing strip to not generate such ELF files and recompiling gzip with the fixed strip.

  [Test Case]

   * Check the gzip binary for wrong offset:
    $ FILE=/usr/bin/gzip; readelf -W --program-headers $FILE | awk -v size=$(stat -c %s $FILE) '/^  LOAD/ {if (strtonum($2) > size) {print "wrong offset ("$2" ("strtonum($2)") points past EOF:" size; exit 1;}}'

  [ Regression Potential ]

   * The binutils fix could cause binutils to generate invalid ELF files. The fix is very small and isolated and has been tested and accepted by upstream, which makes such problems unlikely.
   * Bugs in the toolchain in general can make the rebuilt gzip show new errors, but this generally applies to many SRUs and security updates. The testing period in proposed should mitigate this risk.

  [Originial Bug Text]

  Summary:

  Running gzip on WSL1 results in the following error:

  $ gzip
  -bash: /bin/gzip: cannot execute binary file: Exec format error

  What I expect to happen:

  gzip executes correctly on WSL1.

  What happens instead:

  gzip fails with an Exec format error.

  Notes:

  I suspect a change in how gzip is being built for Eoan is causing
  issues with ELF parsing on the WSL1 translation layer. For example:

  On Disco with gzip 1.9-3:

  $ file /bin/gzip
  /bin/gzip: ELF 64-bit LSB pie executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 3.2.0, BuildID[sha1]=efa859c26eaf8e035efe9a139361e2a60cd17b3e, stripped

  On Eoan with gzip 1.10-0ubuntu3:

  $ file /bin/gzip
  /bin/gzip: ELF 64-bit LSB pie executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, BuildID[sha1]=bc0f5994544c2a469d04c914bf4bf44b4ded6040, for GNU/Linux 3.2.0, stripped

  Eoan ships with gzip 1.10, while Disco ships with gzip 1.9, but I do
  not believe this is an issue in 1.10 because this error does not occur
  when building gzip from GNU project source on Ubuntu Eoan.

  Justifications:

  WSL1 will need to be patched in future Windows builds for this change
  in ELF. However that patch will likely not be backported to older
  builds of Windows, including Windows Enterprise/Server 2019.

  To ensure Eoan can run on current and older builds of Windows Ubuntu
  should consider looking at how it's building gzip and see if it can be
  made to 'play nice' until WSL1 can be updated.

  This was originally reported here:
  https://github.com/microsoft/WSL/issues/4461

  Details:

  Description:    Ubuntu Eoan Ermine (development branch)
  Release:        19.10

  gzip:
    Installed: 1.10-0ubuntu3
    Candidate: 1.10-0ubuntu3
    Version table:
   *** 1.10-0ubuntu3 500
          500 http://archive.ubuntu.com/ubuntu eoan/main amd64 Packages
          100 /var/lib/dpkg/status

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