file corruption when copying from iso9660 with bad rrversion

[ge0rg]

When opening certain ISO files with mc, I get an error pop-up on the first open, which can be dismissed:

However, when copying individual files from such an ISO to another directory using [F5], mc will silently attach the same string ("**BAD RRVERSION (0)") to all copied files, making them 20 bytes larger than the source, and corrupting all file formats that expect their header at the end.

This looks related to #4326.

The only ISO I have seen this happen on yet is a proprietary driver CD from Samsung from 2014, to which I can share a link privately on request.

Tested on Debian-provided mc, mc -V:

GNU Midnight Commander 4.8.29
Built with GLib 2.74.5
Built with S-Lang 2.3.3 with terminfo database
Built with libssh2 1.10.0
With builtin Editor and Aspell support
With subshell support as default
With support for background operations
With mouse support on xterm and Linux console
With support for X11 events
With internationalization support
With multiple codepages support
With ext2fs attributes support
Virtual File Systems:
 cpiofs, tarfs, sfs, extfs, ext2undelfs, ftpfs, sftpfs, fish
Data types:
 char: 8; int: 32; long: 64; void *: 64; size_t: 64; off_t: 64;

mc --configure-options:

 '--build=x86_64-linux-gnu' '--prefix=/usr' '--includedir=${prefix}/include' '--mandir=${prefix}/share/man' '--infodir=${prefix}/share/info' '--sysconfdir=/etc' '--localstatedir=/var' '--disable-option-checking' '--libdir=${prefix}/lib/x86_64-linux-gnu' '--runstatedir=/run' '--disable-maintainer-mode' '--disable-dependency-tracking' 'AWK=awk' 'X11_WWW=x-www-browser' '--libexecdir=/usr/lib' '--with-x' '--with-screen=slang' '--disable-rpath' '--disable-static' '--disable-silent-rules' '--enable-aspell' '--enable-vfs-sftp' '--enable-vfs-undelfs' '--enable-tests' 'build_alias=x86_64-linux-gnu' 'CFLAGS=-g -O2 -ffile-prefix-map=/build/mc-3Uz4Lz/mc-4.8.29=. -fstack-protector-strong -Wformat -Werror=format-security' 'LDFLAGS=-Wl,-z,relro -Wl,-z,now -Wl,--as-needed' 'CPPFLAGS=-Wdate-time -D_FORTIFY_SOURCE=2'

[zaytsev]

Why do you think it relates to #4326 ? In that ticket it was showing the message, because isoinfo detection wasn't working correctly, however in your case it seems that isoinfo is present, but cannot parse a specific ISO file.

We don't need the CD, but we need the output of isoinfo and better still test data like here:

​https://github.com/MidnightCommander/mc/tree/master/tests/src/vfs/extfs/helpers-list/data

So see where the RRVERSION comes from when parsing file list by isoinfo:

​https://github.com/MidnightCommander/mc/blob/master/src/vfs/extfs/helpers/iso9660.in

[ge0rg]

Yes, isoinfo is present, but emits the warning when passed -R (I was erroneously assuming that the warning is output to stderr, but it's actually on stdout).

On the other hand, isoinfo -d reports "NO Rock Ridge present" for this disk, so maybe the ​unconditional adding of -R in line 117 is the actual bug?

$ isoinfo -i nx-mini-software.iso                                                                  
$ isoinfo -i nx-mini-software.iso -R
**BAD RRVERSION (0)
$ isoinfo -d -R -i nx-mini-software.iso  
CD-ROM is in ISO 9660 format
System id: 
Volume id: SAMSUNG
Volume set id: 
Publisher id: 
Data preparer id: 
Application id: NERO BURNING ROM
Copyright File id: 
Abstract File id: 
Bibliographic File id: 
Volume set size is: 1
Volume set sequence number is: 1
Logical block size is: 2048
Volume size is: 152704
Joliet with UCS level 3 found
NO Rock Ridge present
$ isoinfo -i nx-mini-software.iso -R > /dev/null 
$ isoinfo -R -J -f -i nx-mini-software.iso  
**BAD RRVERSION (0)
/Autorun.inf;1
/Mac
/Manual
/Windows
[...snipped...]
$ isoinfo -J -i nx-mini-software.iso -x '/Windows/i-Launcher/i-Launcher_setup.exe;1' |grep RRVERSION
$ isoinfo -R -J -i nx-mini-software.iso -x '/Windows/i-Launcher/i-Launcher_setup.exe;1' |grep RRVERSION
Binary file (standard input) matches
$

[zaytsev]

It was added in #4326, but I don't know why.

Maybe you are right and the "correct" solution would be to do something like

if [ $(echo "$ISOINFO_D_I" | grep "NO Rock Ridge" | wc -l) = 0 ] ; then
    ISOINFO="$ISOINFO -R"
fi

I would very much like to have test data for this before making further changes to the script though :(

​https://github.com/MidnightCommander/mc/tree/master/tests/src/vfs/extfs/helpers-list/data

[ge0rg]

I have looked into the test data directory, but I don't know enough about the required data structure to provide useful files. My naive hope was that the above paste would be sufficient to at least generate an RR test case.

Do you need input/output pairs for simulating isoinfo calls? With which parameters? Or do you need input files to pass into isoinfo? How are different test cases separated?

I suppose I could create something based on my "broken" ISO and maybe also on another good one, if you can provide a howto for creating test cases ;)

[zaytsev]

We need output example of isoinfo and correct output of the helper on the basis of this input. You can have a look how to add tests for example in this commit:

​https://github.com/MidnightCommander/mc/commit/d4ec872f37afa394e5aec9879bbf6d4d80a1964a

Just browse the directory on GitHub? to see other commits which might provide good examples:

​https://github.com/MidnightCommander/mc/tree/master/tests/src/vfs/extfs/helpers-list/data

The point is that if you adjust the script blindly the possibility to break everything is very high. If you have example output of the backing tool and desired output of the script, you can make sure that it's not breaking like in #4326 when fixing an unrelated topic.

[andrew_b]

I'm creating an ISO image w/o Rock Ridge:

$ genisoimage --input-charset=utf-8 -o test.iso tmp/1.txt
Total translation table size: 0
Total rockridge attributes bytes: 0
Total directory bytes: 0
Path table size(bytes): 10
Max brk space used 0
174 extents written (0 MB)

$ isoinfo -d -R -i test.iso 
CD-ROM is in ISO 9660 format
System id: LINUX
Volume id: CDROM
Volume set id: 
Publisher id: 
Data preparer id: 
Application id: GENISOIMAGE ISO 9660/HFS FILESYSTEM CREATOR (C) 1993 E.YOUNGDALE (C) 1997-2006 J.PEARSON/J.SCHILLING (C) 2006-2007 CDRKIT TEAM
Copyright File id: 
Abstract File id: 
Bibliographic File id: 
Volume set size is: 1
Volume set sequence number is: 1
Logical block size is: 2048
Volume size is: 174
NO Joliet present
NO Rock Ridge present

There is no error.

$ isoinfo --version
isoinfo 1.1.11 (Linux)

from cdrkit-1.1.11

What isoinfo are you using?

[zaytsev]

In his case this command also doesn't output an error, but this one does:

$ isoinfo -R -J -f -i nx-mini-software.iso 

(without -d - see pastes above)

[andrew_b]

$ isoinfo -R -J -f -i test.iso 
isoinfo: Unable to find Joliet SVD