USB problem: /dev/ugen* dynamically auto-reconfigures to
root:operator 644, so non-root user unable to access USB devices
even if wanted
Andreas Klemm
andreas at freebsd.org
Mon Oct 20 03:10:20 PDT 2003
Hi,
have severe problems accessing usb devices as non-root user.
In this case a Canon Powershot G5 camera.
I want to download pics from my digicam using digikam application
as user "andreas".
The devices that are being used by digikam:
root at titan[ttyp2]{57} ~ lsof | grep digikam | grep /dev
digikam 1755 root 0u VCHR 5,2 0t19646 110 /dev/ttyp2
digikam 1755 root 1u VCHR 5,2 0t19646 110 /dev/ttyp2
digikam 1755 root 2u VCHR 5,2 0t19646 110 /dev/ttyp2
digikam 1755 root 15u VCHR 114,16 0t0 128 /dev/ugen1
digikam 1755 root 16r VCHR 114,17 0t7817 131 /dev/ugen1.1
digikam 1755 root 17r VCHR 114,19 0t16 133 /dev/ugen1.3
Running digikam with SUID root bit turned on doesn't work.
andreas at titan[ttyp4]{1032} ~ digikam
The KDE libraries are not designed to run with suid privileges.
Changing the permissions on /dev/ugen1* doesn't work either since
- even _if_ the devices are present after turning camera on and
- even _if_ permissions of /dev/ugen1 /dev/ugen1.1 ... 1.3 are
being changed successfully to 666
the devices seems to be on the 1st access dynamically recreated,
since the permissions suddenly are *re-set* to root 644 automagically
after the 1st access of the digikam application as user.
To sum up: as normal user I'm unable to connect to the USB camera.
Is there a more generic approach to be able to use USB
devices as non-root user, that I overlooked up to now ?
Andreas ///
--
Andreas Klemm - Powered by FreeBSD 5.1-CURRENT
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