[Qemu-devel] [PATCH 00/10] block/dmg: (compatibility) fixes and bzip2 support

[Peter Wu]

Hi,

These series improve QEMU support for DMG image files:

 - Images which are not multiples of a block size (512) are now properly
   recognized ("properly detect the UDIF trailer").
 - Block descriptors stored in the XML plist section rather than the Resource
   Fork are now recognized ("process XML plists").
 - The virtual (uncompressed) image size is now advertised ("set virtual size to
   a non-zero value").
 - Files which have a different data offsets are now properly handled ("fix
   sector data offset calculation").
 - bzip2-compressed chunks can now be read ("support bzip2 block entry types").
   This adds a new --enable-bzip2 option.
 - Files with a large all-zeroes data chunk do not trip an error anymore
   ("improve zeroes handling").

The XML plist patch depends on these refactorings (which add no new
functionality):

  block/dmg: extract mish block decoding functionality
  block/dmg: extract processing of resource forks
  block/dmg: process a buffer instead of reading ints

Finally there is this patch which avoids a DoS (large memory allocation) due to
a missing check on untrusted data:

  block/dmg: validate chunk size to avoid overflow

These patches were tested against disk images, but since DMG files are also used
for installers, I used those too. The following files pass these patches:
 - filename + source; real size in bytes; publication date. (additional info:
   whether BLXX is stored in XML plists or a resource fork; compression method)
 - espgs-7.05.5-0.ppc.dmg[1]            5593786 2002-09 (rsrc fork, zlib, sector
                                                         offsets start at 0)
 - Wireshark 1.12.2 Intel 64.dmg[2]    26375047 2014-11 (xml, zlib)
 - tuxpaint-0.9.15-macosx.dmg[3]        9022458 2005-11 (rsrc fork, zlib)
 - vlc-2.1.5.dmg[4]                    33519849 2014-07 (xml, bzlib)
 - OS X Yosemite.dmg                 5189100314 2014-10 (xml, bzlib)
 - InstallESD.dmg (in prev. image)   5164763151 2014-10 (xml, zlib; data offset
                                                         is non-zero)

For these above files, I executed `qemu-img info foo.dmg` to verify that there 
is
no EINVAL error and `qemu-img convert -f dmg -O raw foo.dmg foo.raw` to check
whether reading works. The resulting `foo.raw` was then compared against
`foo.img` as generated by `dmg2img foo.dmg`.

This file was tested and 'qemu-img info' works properly, but conversion failed
because the Apple Data Compression (ADC) format is not supported[5].
 - NetBoot9.dmg[6]                    534884900 2003-09 (rsrc fork, adc)

These patches (rebased against current master) can be found at:
https://git.lekensteyn.nl/peter/qemu/log/?h=block-dmg-2.3
(development and testing was done against v2.2.0, branch block-dmg-2.2)

Kind regards,
Peter

 [1]: http://sourceforge.net/projects/espgs/files/espgs/7.05.5/
 [2]: https://www.wireshark.org/download/osx/
 [3]: http://sourceforge.net/projects/tuxpaint/files/tuxpaint/0.9.15/
 [4]: http://download.videolan.org/pub/videolan/vlc/2.1.5/macosx/
 [5]: https://bugzilla.redhat.com/show_bug.cgi?id=1058132
 [6]: 
http://download.info.apple.com/Mac_OS_X/693-4445.20030912.gnr39/NetBoot9.dmg
--
Peter Wu (10):
  block/dmg: properly detect the UDIF trailer
  block/dmg: extract mish block decoding functionality
  block/dmg: extract processing of resource forks
  block/dmg: process a buffer instead of reading ints
  block/dmg: validate chunk size to avoid overflow
  block/dmg: process XML plists
  block/dmg: set virtual size to a non-zero value
  block/dmg: fix sector data offset calculation
  block/dmg: support bzip2 block entry types
  block/dmg: improve zeroes handling

 block/dmg.c | 475 +++++++++++++++++++++++++++++++++++++++++++++---------------
 configure   |  31 ++++
 2 files changed, 390 insertions(+), 116 deletions(-)

-- 
2.2.1