1. 21 Sep, 2011 1 commit
    • Lasse Collin's avatar
      XZ: Fix incorrect XZ_BUF_ERROR · 9c1f8594
      Lasse Collin authored
      xz_dec_run() could incorrectly return XZ_BUF_ERROR if all of the
      following was true:
       - The caller knows how many bytes of output to expect and only provides
         that much output space.
       - When the last output bytes are decoded, the caller-provided input
         buffer ends right before the LZMA2 end of payload marker.  So LZMA2
         won't provide more output anymore, but it won't know it yet and thus
         won't return XZ_STREAM_END yet.
       - A BCJ filter is in use and it hasn't left any unfiltered bytes in the
         temp buffer.  This can happen with any BCJ filter, but in practice
         it's more likely with filters other than the x86 BCJ.
      This fixes <https://bugzilla.redhat.com/show_bug.cgi?id=735408> where
      Squashfs thinks that a valid file system is corrupt.
      This also fixes a similar bug in single-call mode where the uncompressed
      size of a block using BCJ + LZMA2 was 0 bytes and caller provided no
      output space.  Many empty .xz files don't contain any blocks and thus
      don't trigger this bug.
      This also tweaks a closely related detail: xz_dec_bcj_run() could call
      xz_dec_lzma2_run() to decode into temp buffer when it was known to be
      useless.  This was harmless although it wasted a minuscule number of CPU
      Signed-off-by: default avatarLasse Collin <lasse.collin@tukaani.org>
      Cc: stable <stable@kernel.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
  2. 13 Jan, 2011 1 commit
    • Lasse Collin's avatar
      decompressors: add XZ decompressor module · 24fa0402
      Lasse Collin authored
      In userspace, the .lzma format has become mostly a legacy file format that
      got superseded by the .xz format.  Similarly, LZMA Utils was superseded by
      XZ Utils.
      These patches add support for XZ decompression into the kernel.  Most of
      the code is as is from XZ Embedded <http://tukaani.org/xz/embedded.html>.
      It was written for the Linux kernel but is usable in other projects too.
      Advantages of XZ over the current LZMA code in the kernel:
        - Nice API that can be used by other kernel modules; it's
          not limited to kernel, initramfs, and initrd decompression.
        - Integrity check support (CRC32)
        - BCJ filters improve compression of executable code on
          certain architectures. These together with LZMA2 can
          produce a few percent smaller kernel or Squashfs images
          than plain LZMA without making the decompression slower.
      This patch: Add the main decompression code (xz_dec), testing module
      (xz_dec_test), wrapper script (xz_wrap.sh) for the xz command line tool,
      and documentation.  The xz_dec module is enough to have a usable XZ
      decompressor e.g.  for Squashfs.
      Signed-off-by: default avatarLasse Collin <lasse.collin@tukaani.org>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Alain Knaff <alain@knaff.lu>
      Cc: Albin Tonnerre <albin.tonnerre@free-electrons.com>
      Cc: Phillip Lougher <phillip@lougher.demon.co.uk>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>