[0/4] usbip synchronize sysfs code paths

Message

Shuah Khan March 30, 2021, 1:36 a.m. UTC

Fuzzing uncovered race condition between sysfs code paths in usbip
drivers. Device connect/disconnect code paths initiated through
sysfs interface are prone to races if disconnect happens during
connect and vice versa.

This problem is common to all drivers while it can be reproduced easily
in vhci_hcd. Add a sysfs_lock to usbip_device struct to protect the paths.

For a complete fix, all usbip drivers have to use sysfs_lock to protect
sysfs code paths and common event handler will have to use this lock to
synchonize with the sysfs paths in drivers.

This patch series adds sysfs_lock and uses it in vhci_hcd in the first
patch. Subsequent patches fix usbip_host, vudc and the last patch fixes
the common event handler code path.

Shuah Khan (4):
  usbip: add sysfs_lock to synchronize sysfs code paths
  usbip: stub-dev synchronize sysfs code paths
  usbip: vudc synchronize sysfs code paths
  usbip: synchronize event handler with sysfs code paths

 drivers/usb/usbip/stub_dev.c     | 11 +++++++++--
 drivers/usb/usbip/usbip_common.h |  3 +++
 drivers/usb/usbip/usbip_event.c  |  2 ++
 drivers/usb/usbip/vhci_hcd.c     |  1 +
 drivers/usb/usbip/vhci_sysfs.c   | 30 +++++++++++++++++++++++++-----
 drivers/usb/usbip/vudc_dev.c     |  1 +
 drivers/usb/usbip/vudc_sysfs.c   |  5 +++++
 7 files changed, 46 insertions(+), 7 deletions(-)