[Bug 2018293] Re: [UBUNTU 20.04] Crash in zlib deflateBound() function on s390x

[Julian Andres Klode]

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** Changed in: zlib (Ubuntu Mantic)
       Status: In Progress => Fix Committed

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https://bugs.launchpad.net/bugs/2018293

Title:
  [UBUNTU 20.04] Crash in zlib deflateBound() function on s390x

Status in Ubuntu on IBM z Systems:
  In Progress
Status in zlib package in Ubuntu:
  Fix Committed
Status in zlib source package in Focal:
  New
Status in zlib source package in Jammy:
  New
Status in zlib source package in Lunar:
  New
Status in zlib source package in Mantic:
  Fix Committed

Bug description:
  SRU Justification:
  ==================

  [ Impact ]

   * The zlib deflateBound() function can crash on s390x,
     if called before deflateInit().

   * The solution is that zlib on s390x needs to support
     calling deflateBound() always before deflateInit().

  [ Test Plan ]

   * It's suggested to do a more overall or e2e test
     and run the zlib-ng test suite against the system zlib
     as follows:
     $ git clone https://github.com/zlib-ng/zlib-ng.git
     $ cd zlib-ng
     $ cmake -DZLIB_COMPAT=ON -DZLIBNG_ENABLE_TESTS=OFF -DBUILD_SHARED_LIBS=ON -DWITH_DFLTCC_DEFLATE=ON -DWITH_DFLTCC_INFLATE=ON .
     $ make gtest_zlib
     $ ldd gtest_zlib
       libz.so.1 => /lib/s390x-linux-gnu/libz.so.1 (0x000003fff7e00000)
     $ ./gtest_zlib

  [ Where problems could occur ]

   * The only (single line) modification is in the if condition
     of the define DEFLATE_BOUND_ADJUST_COMPLEN statement in
     deflate.c.

   * Things can go wrong if the condition (or logic) is wrong,

   * or if other parts of the code are coded against the old behavior
     and are still expecting it.

   * The likely outcome would be still a crash
     or an unexpected behavior.

  [ Other Info ]

   * Getting this into mantic first,
     before the SRU down to focal is done.
  __________

  Problem Description:
  zlib deflateBound() function can crash on s390x when called before deflateInit().

  Solution:
  zlib on s390x needs to support calling deflateBound() before deflateInit().

  The fix is squashed into the latest DFLTCC PR:
  https://github.com/madler/zlib/pull/410

  Diff:
  https://github.com/madler/zlib/compare/113203437eda67261848b14b6c80a33ff7e33d34..f6d382a91a4e7d88b9b12ce0ecdffb1783878160

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