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The new USBDEVFS_DROP_PRIVILEGES ioctl allows a process to voluntarily relinquish the ability to issue other ioctls that may interfere with other processes and drivers that have claimed an interface on the device. This commit also includes a simple utility to be able to test the ioctl, located at Documentation/usb/usbdevfs-drop-permissions.c Example (with qemu-kvm's input device): $ lsusb ... Bus 001 Device 002: ID 0627:0001 Adomax Technology Co., Ltd $ usb-devices ... C: #Ifs= 1 Cfg#= 1 Atr=a0 MxPwr=100mA I: If#= 0 Alt= 0 #EPs= 1 Cls=03(HID ) Sub=00 Prot=02 Driver=usbhid $ sudo ./usbdevfs-drop-permissions /dev/bus/usb/001/002 OK: privileges dropped! Available options: [0] Exit now [1] Reset device. Should fail if device is in use [2] Claim 4 interfaces. Should succeed where not in use [3] Narrow interface permission mask Which option shall I run?: 1 ERROR: USBDEVFS_RESET failed! (1 - Operation not permitted) Which test shall I run next?: 2 ERROR claiming if 0 (1 - Operation not permitted) ERROR claiming if 1 (1 - Operation not permitted) ERROR claiming if 2 (1 - Operation not permitted) ERROR claiming if 3 (1 - Operation not permitted) Which test shall I run next?: 0 After unbinding usbhid: $ usb-devices ... I: If#= 0 Alt= 0 #EPs= 1 Cls=03(HID ) Sub=00 Prot=02 Driver=(none) $ sudo ./usbdevfs-drop-permissions /dev/bus/usb/001/002 ... Which option shall I run?: 2 OK: claimed if 0 ERROR claiming if 1 (1 - Operation not permitted) ERROR claiming if 2 (1 - Operation not permitted) ERROR claiming if 3 (1 - Operation not permitted) Which test shall I run next?: 1 OK: USBDEVFS_RESET succeeded Which test shall I run next?: 0 After unbinding usbhid and restricting the mask: $ sudo ./usbdevfs-drop-permissions /dev/bus/usb/001/002 ... Which option shall I run?: 3 Insert new mask: 0 OK: privileges dropped! Which test shall I run next?: 2 ERROR claiming if 0 (1 - Operation not permitted) ERROR claiming if 1 (1 - Operation not permitted) ERROR claiming if 2 (1 - Operation not permitted) ERROR claiming if 3 (1 - Operation not permitted) Signed-off-by: Reilly Grant <reillyg@chromium.org> Acked-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Emilio López <emilio.lopez@collabora.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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media | ||
.gitignore | ||
80211.tmpl | ||
alsa-driver-api.tmpl | ||
crypto-API.tmpl | ||
debugobjects.tmpl | ||
device-drivers.tmpl | ||
deviceiobook.tmpl | ||
filesystems.tmpl | ||
gadget.tmpl | ||
genericirq.tmpl | ||
gpu.tmpl | ||
iio.tmpl | ||
kernel-api.tmpl | ||
kernel-hacking.tmpl | ||
kernel-locking.tmpl | ||
kgdb.tmpl | ||
libata.tmpl | ||
librs.tmpl | ||
lsm.tmpl | ||
Makefile | ||
media_api.tmpl | ||
mtdnand.tmpl | ||
networking.tmpl | ||
rapidio.tmpl | ||
regulator.tmpl | ||
s390-drivers.tmpl | ||
scsi.tmpl | ||
sh.tmpl | ||
stylesheet.xsl | ||
tracepoint.tmpl | ||
uio-howto.tmpl | ||
usb.tmpl | ||
w1.tmpl | ||
writing_musb_glue_layer.tmpl | ||
writing_usb_driver.tmpl | ||
writing-an-alsa-driver.tmpl | ||
z8530book.tmpl |