Czuczy Gergely wrote: > Peter Selinger wrote: > > > (1) Could you please run the two commands again, but this time, with > > the environment variable USB_DEBUG=3, i.e., like this (assuming you > > are using bash): > > > > USB_DEBUG=3 /lib/nut/newhidups -u nut -DD -a ups1 > > debug level is '2' > usb_set_debug: Setting debugging level to 3 (on) > usb_os_init: Found USB VFS at /dev/usb > .... > > > USB_DEBUG=3 /lib/nut/newhidups -u root -DD -a ups1 > > debug level is '2' > usb_set_debug: Setting debugging level to 3 (on) > usb_os_init: Found USB VFS at /proc/bus/usb > ....
Now this is interesting. Here your bug is clearly visible. When running with "-u nut", libusb-0.1.10a looks in "/dev/usb", instead of "/proc/bus/usb". It is not very surprising that it does not find any useful devices. A quick look at libusb-0.1.10a/linux.c (line 610, function usb_os_init) reveals that libusb first checks /proc/bus/usb, and if that is not readable, then it checks /sys/bus/usb and finally /dev/usb. More specifically, what it does is it opens each directory and looks for a file whose name does not start with ".". It does not attempt to open any files, it only attempts to list the directory. This confirms that /proc/bus/usb (the directory), for some reason, is not readable by the "nut" user, despite dr-xr-xr-x 1 nut nut 0 2006-04-06 17:10 /proc/bus/usb dr-xr-x--- 4 root 6661 0 2006-04-06 17:10 /proc/bus > > (2) is your machine running any access control system, such as > > SELinux, which might restrict access to the USB system? > nope. only grsecurity, but this part is not restricted i think. > we usually do network-related restrictions. The grsecurity website mentions Role-Based Access Control as one of their features. This could mean that some special files are subject to a security policy. (5) What do the following show? getfacl /proc/bus getfacl /proc/bus/usb (6) Is it possible to list the contents of /proc/bus/usb as an ordinary non-root user? (7) Can the "nut" user list the contents of /proc/bus/usb? The "nut" user has no shell or password, but you should be able to test this as follows (as root): sudo -u nut ls -Ral /proc/bus/usb -- Peter _______________________________________________ Nut-upsuser mailing list [email protected] http://lists.alioth.debian.org/mailman/listinfo/nut-upsuser
