Commit e9828cdd authored by Thomas Schmitt's avatar Thomas Schmitt

Mentioned Solaris and system dependent drive permission settings

parent 7f035889
......@@ -145,6 +145,8 @@ The project components (list subject to growth, hopefully):
also allows to grow ISO-9660 filesystem images on multi-session
media as well as on overwriteable media via the same API.
All media peculiarities are handled automatically.
It also contains the methods of command oriented application
xorriso and offers them via a C language API.
- cdrskin is a limited cdrecord compatibility wrapper for libburn.
cdrecord is a powerful GPL'ed burn program included in Joerg
......@@ -164,6 +166,8 @@ The project components (list subject to growth, hopefully):
changing, incremental backups, activating boot images, and
extracting of files from ISO images to disk. An own ISO 9660
extension stores ACLs, xattr, and MD5 of file content.
All features of xorriso are also available via a C language API
of libisoburn.
See xorriso/README for more.
- "test" is a collection of application gestures and examples given by the
......
......@@ -104,17 +104,25 @@ The output of cdrskin --devices might look like
0 dev='/dev/sr0' rwrwr- : '_NEC' 'DVD_RW ND-4570A'
1 dev='/dev/sr1' rwrw-- : 'HL-DT-ST' 'DVDRAM GSA-4082B'
So full and insecure enabling of both for everybody would look like
chmod a+rw /dev/sr0 /dev/sr1
On Linux, full and insecure enabling of both for everybody would look like
chmod a+rw /dev/sr0 /dev/hda
This is equivalent to the traditional setup chmod a+x,u+s cdrecord.
On FreeBSD, device permissions are to be set in /etc/devfs.rules.
On Solaris, pfexec privileges may be restricted to "base,sys_devices".
See below "System Dependend Drive Permission Examples".
I strongly discourage to run cdrskin with setuid root or via sudo !
It is not checked for the necessary degree of hacker safety.
Better consider to grant the necessary permissions to group "floppy"
and to add users to it.
A behavioral conflict is known between any burn software and demons like hald
which probe CD drives. This can spoil burn runs for CD-R or CD-RW.
You may have to keep your hald away from the drive. See for example
http://www.freebsd.org/gnome/docs/halfaq.html
Consider to put all authorized users into group "floppy", to chgrp the
device file to that group and to disallow w-access to others.
Helpful with Linux kernel 2.4 is a special SCSI feature:
It is possible to address a scsi(-emulated) drive via associated device files
......@@ -123,11 +131,6 @@ as listed device files. This addressing via e.g. /dev/sr0 or /dev/scd1 is
compatible with generic read programs like dd and with write program growisofs.
For finding /dev/sg1 from /dev/sr0, the program needs rw-access to both files.
A behavioral conflict is known between any burn software and demons like hald
which probe CD drives. This can spoil burn runs for CD-R or CD-RW.
You may have to keep your hald away from the drive. See for example
http://www.freebsd.org/gnome/docs/halfaq.html
Usage examples
......@@ -434,6 +437,77 @@ It will not read startup files, will abort on option dev_translation= ,
will not have a fifo buffer, and will not be able to put out help texts or
debugging messages.
------------------------------------------------------------------------------
System Dependend Drive Permission Examples
Accessing the optical drives requires privileges which usually are granted
only to the superuser. Linux, FreeBSD and Solaris offer quite different
approaches for avoiding the need for unrestricted privileges.
---------------------
On all three systems:
---------------------
Add the authorized user of CD drives to group "floppy" in /etc/group.
If missing: create this group.
Changes to /etc/group often only affect new login sessions. So log out and in
before making the first tests.
---------
On Linux:
---------
Allow rw-access to the drives
chgrp floppy /dev/sr0 /dev/sr1
chmod g+rw /dev/sr0 /dev/sr1
It might be necessary to perform chgrp and chmod after each reboot or to
edit distro dependent device configuration files for permanent settings.
-----------
On FreeBSD:
-----------
On FreeBSD:
Edit /etc/devfs.rules and make sure to have these lines
[localrules=10]
add path 'acd*' mode 0664 group floppy
add path 'cd*' mode 0664 group floppy
add path 'pass*' mode 0664 group floppy
add path 'xpt*' mode 0664 group floppy
[localrules=5]
add path 'pass*' mode 0664 group floppy
add path 'cd*' mode 0664 group floppy
add path 'xpt*' mode 0664 group floppy
add path 'acd*' mode 0664 group floppy
Edit /etc/rc.conf and add the following line if missing
devfs_system_ruleset="localrules"
This gets into effect by reboot or by command
/etc/rc.d/devfs start
-----------
On Solaris:
-----------
Run cdrskin by
pfexec cdrskin ...arguments...
The following settings will make pfexec keep original UID and EUID and prevent
most superuser powers. Be aware that you still can manipulate all device files
if you have the file permissions for that.
Full root privileges for cdrskin can then be aquired only by command su.
Edit /etc/security/exec_attr and add this line to the other "Media Backup"
lines:
Media Backup:solaris:cmd:::/usr/local/bin/cdrskin:privs=basic,sys_devices
Edit /etc/user_attr and add profile "Media Backup" to the user's line:
thomas::::profiles=Media Backup,Primary Administrator;roles=root
See also man privileges, man exec_attr, man user_attr.
Then allow the group r-access to the drives
pfexec chgrp floppy /dev/rdsk/c3t0d0s2 /dev/rdsk/c4t0d0s2
pfexec chmod g+r /dev/rdsk/c3t0d0s2 /dev/rdsk/c4t0d0s2
The last two commands have to be executed after each boot. I do not know
the relevant device configuration files yet.
------------------------------------------------------------------------------
Project aspects and legal stuff
......
......@@ -2,7 +2,7 @@
.\" First parameter, NAME, should be all caps
.\" Second parameter, SECTION, should be 1-8, maybe w/ subsection
.\" other parameters are allowed: see man(7), man(1)
.TH CDRSKIN 1 "Feb 29, 2010"
.TH CDRSKIN 1 "Jun 10, 2010"
.\" Please adjust this date whenever revising the manpage.
.\"
.\" Some roff macros, for reference:
......@@ -271,19 +271,22 @@ the drive is somewhat higher but the overall system is much less at stake.
Consider to restrict rw-access to a single group which bundles the users who
are allowed to use the burner drive (like group "floppy").
.br
For drive permission examples on Linux, FreeBSD, and Solaris,
see cdrskin/README.
.br
.PP
If you only got one CD capable drive then you may leave out cdrskin option
\fBdev=\fP. Else you should use this option to address the drive you want.
.br
cdrskin option dev= not only accepts the listed addresses but also
traditional cdrecord SCSI addresses which on Linux consist of three
numbers: Bus,Target,Lun. There is also a related address family "ATA" which
traditional cdrecord SCSI addresses which consist of three numbers:
Bus,Target,Lun. On Linux there is also a related address family "ATA" which
accesses IDE drives not under control of Linux SCSI drivers:
ATA:Bus,Target,Lun.
.br
See option -scanbus for getting a list of cdrecord style addresses.
.br
Further are accepted on Linux: links to libburn-suitable device files,
Further are accepted: links to libburn-suitable device files,
device files which have the same major and minor device number,
and device files which have the same SCSI address parameters (e.g. /dev/sg0).
.br
......
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