Re: USB permissions

[Mark Rivers via Tech-talk <tech-talk at aps.anl.gov>]

Hi Jorn,

You’re right, that directory has a lot of .rules files in it, including 50-uldaq.rules. I am quite sure I did not explicitly put it there since I did not know about that location. I need to figure out what package installed it.

Thanks,
Mark


Sent from my iPhone

> On Sep 25, 2023, at 10:46 PM, Jörn Dreyer <j.dreyer at hzdr.de> wrote:
> 
> Hi Mark,
> 
> on some systems, especially those with systemd, there is another directory 
> where udev looks for rules files. Did you check in
> 
> /usr/lib/udev/rules.d
> 
> for a file that might set the permissions for those devices?
> 
> Regards
> 
> Jörn
> 
> Am Montag, 25. September 2023, 23:52:10 CEST schrieb Mark Rivers via Tech-
> talk:
>> Folks,
>> 
>> I am seeing something I don't understand about USB device permissions on
>> Linux.  I have two Centos 9 systems, each connected to 3 USB devices from
>> Measurement Computing.
>> 
>> On the system called 13ide I needed to install a udev rules file in order to
>> give these USB devices world write permission.
>> 
>> This is part of the rules file:
>> 
>> (base) [epics@13ide ~]$ more /etc/udev/rules.d/50-uldaq.rules
>> SUBSYSTEM=="usb", ATTR{idVendor}=="09db", ATTR{idProduct}=="0076",
>> GROUP="adm", MODE="0666" SUBSYSTEM=="usb", ATTR{idVendor}=="09db",
>> ATTR{idProduct}=="007f", GROUP="adm", MODE="0666" SUBSYSTEM=="usb",
>> ATTR{idVendor}=="09db", ATTR{idProduct}=="0085", GROUP="adm", MODE="0666"
>> SUBSYSTEM=="usb", ATTR{idVendor}=="09db", ATTR{idProduct}=="0086",
>> GROUP="adm", MODE="0666" SUBSYSTEM=="usb", ATTR{idVendor}=="09db",
>> ATTR{idProduct}=="008a", GROUP="adm", MODE="0666"
>> 
>> lsusb shows that the devices are on bus 002, devices 005, 007, and 008.
>> 
>> (base) [epics@13ide ~]$ lsusb
>> Bus 002 Device 009: ID 0557:2259 ATEN International Co., Ltd LCD Console
>> V1.3.124 Bus 002 Device 006: ID 0557:2259 ATEN International Co., Ltd LCD
>> Console V1.3.124 Bus 002 Device 004: ID 0557:8021 ATEN International Co.,
>> Ltd Hub
>> Bus 002 Device 008: ID 09db:013e Measurement Computing Corp. USB-1808X
>> Bus 002 Device 007: ID 09db:009d Measurement Computing Corp. USB-3104
>> Bus 002 Device 005: ID 09db:0127 Measurement Computing Corp. USB-CTR08
>> 
>> This shows that those devices have permission 666 and are owned by the "adm"
>> group.
>> 
>> (base) [epics@13ide ~]$ ls -l /dev/bus/usb/002
>> total 0
>> crw-rw-r-- 1 root root 189, 128 Sep 19 11:45 001
>> crw-rw-r-- 1 root root 189, 129 Sep 19 11:45 002
>> crw-rw-r-- 1 root root 189, 130 Sep 19 11:45 003
>> crw-rw-r-- 1 root root 189, 131 Sep 19 11:45 004
>> crw-rw-rw- 1 root adm  189, 132 Sep 19 11:45 005
>> crw-rw-r-- 1 root root 189, 133 Sep 19 11:45 006
>> crw-rw-rw- 1 root adm  189, 134 Sep 19 11:45 007
>> crw-rw-rw- 1 root adm  189, 135 Sep 19 11:45 008
>> crw-rw-r-- 1 root root 189, 136 Sep 19 11:45 009
>> 
>> This makes sense to me because permission 666 and group "adm" are in the
>> 50-uldaq.rules file.
>> 
>> However, I have another system which does not have a udev rules file in that
>> location.
>> 
>> [epics@13idc ~]$ ls -l /etc/udev/rules.d/
>> total 0
>> 
>> On that system the devices are on bus 001, devices 004, 005, and 006.
>> 
>> [epics@13idc udev]$ lsusb
>> Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
>> Bus 001 Device 010: ID 1604:10c0 Tascam Dell Integrated Hub
>> Bus 001 Device 009: ID 413c:a102 Dell Computer Corp. iDRAC Virtual NIC
>> Bus 001 Device 007: ID 1604:10c0 Tascam Dell Integrated Hub
>> Bus 001 Device 003: ID 1604:10c0 Tascam Dell Integrated Hub
>> Bus 001 Device 006: ID 09db:013e Measurement Computing Corp. USB-1808X
>> Bus 001 Device 005: ID 09db:009d Measurement Computing Corp. USB-3104
>> Bus 001 Device 004: ID 09db:0127 Measurement Computing Corp. USB-CTR08
>> Bus 001 Device 002: ID 0409:005a NEC Corp. HighSpeed Hub
>> Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
>> 
>> The following shows that these devices also have permissions 666 and are in
>> the "adm" group.
>> 
>> [epics@13idc udev]$ ls -l /dev/bus/usb/001
>> total 0
>> crw-rw-r-- 1 root root 189, 0 Sep 19 12:09 001
>> crw-rw-r-- 1 root root 189, 1 Sep 19 12:09 002
>> crw-rw-r-- 1 root root 189, 2 Sep 19 12:09 003
>> crw-rw-rw- 1 root adm  189, 3 Sep 19 12:09 004
>> crw-rw-rw- 1 root adm  189, 4 Sep 19 12:09 005
>> crw-rw-rw- 1 root adm  189, 5 Sep 19 12:09 006
>> crw-rw-r-- 1 root root 189, 6 Sep 19 12:09 007
>> crw-rw-r-- 1 root root 189, 8 Sep 19 12:09 009
>> crw-rw-r-- 1 root root 189, 9 Sep 19 12:09 010
>> 
>> I don't understand this, since there is no rules file.  How did it know to
>> assign these permissions and group?  Is there another mechanism by which
>> USB devices get permissions assigned?
>> 
>> Thanks,
>> Mark
> 
>