bin/121556: libarchive: ISO9660 decompression extension unsupported

[clemens fischer]

>Number:         121556
>Category:       bin
>Synopsis:       libarchive: ISO9660 decompression extension unsupported
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Mar 10 12:20:01 UTC 2008
>Closed-Date:
>Last-Modified:
>Originator:     clemens fischer <ino-news at spotteswoode.dnsalias.org>
>Release:        FreeBSD 7.0-STABLE i386
>Organization:
>Environment:

FreeBSD 7.0-STABLE #11: Thu Mar 6 13:23:12 CET 2008
root at spotteswoode:/usr/obj/usr/src/sys/spott_fbsd7_i386 i386

userland built a few days before that date.

>Description:

look at <URL:http://www.geexbox.org/en/en/index.html>, download
<URL:http://www1.geexbox.org/releases/1.1/geexbox-1.1-en.i386.iso>.

this is a linux live-CD not installing anything, containing ALSA sound
and a "fat" Mplayer to turn a PC into a "Media Center".  the ISO image
is less than 10MB(!).  the content is decompressed on-the-fly, loaded
into RAM, then does HW-detection and (propably) presents a menu or GUI.

i verified the SHA1 checksum and issued:

  "LC_ALL=C tar -tvf /dl/geexbox-1.1-en.i386.iso"

some of the ISO9660 content is listed, some isn't, eg.:

...
Unsupported RRIP extension for state.cgi
 ZF(12): 70 7a 04 0f ac 0d 00 00 00 00 0d ac
dr-xr-xr-x  2 0      0        2048 Jul  1  2007 GEEXBOX/var/www/img/big
dr-xr-xr-x  2 0      0        2048 Jul  1  2007 GEEXBOX/var/www/cgi-bin
...

i can mount the image on a md(4) device and ls(1) the content, although
most of the files themselves are compressed and cannot be viewed with
fbsd means.

i emailed kientzle@ about this.  he responded fast, with a preliminary
analysis:

> After a little googling around, I finally found a reference
> to the ZF extension:
> 
> http://qa.coreboot.org/docs/doxygen/iso9660_8h-source.html
> 
> 00240 /* Linux-specific extension for transparent decompression */
> 00241 struct RR_ZF{
> 00242   char algorithm[2];
> 00243   char parms[2];
> 00244   char real_size[8];
> 00245 };
> 
> The arguments printed out for this first example
> seem to be:
> 
>   algorithm = "pz" (0x70, 0x7A)
>   parms = [ 4, 15 ] (0x04, 0x0f)
>   real_size = 0x000002b1
> (If you're not familiar with ISO9660, all integers get
> stored twice, first in little-endian order, then in
> big-endian order.  So the 8-byte "real_size" is really
> two copies of a 4-byte integer.)

later he ``found a reference to an "mkzftree" utility'' for me to try to
decompress the image.  i want to do this before trying to burn and run
the ISO on my PC, because i'm afraid to catch a virus, as this "distro"
is very small and the MPlayer alone is so big, which looks suspicious to
me.

>How-To-Repeat:
	
>Fix:

	

regards, clemens
>Release-Note:
>Audit-Trail:
>Unformatted: