usbip: add sysfs_lock to synchronize sysfs code paths

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commit 4e9c93af72 upstream.

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.

Use this in vhci_hcd to protect sysfs paths. For a complete fix, usip_host
and usip-vudc drivers and the event handler will have to use this lock to
protect the paths. These changes will be done in subsequent patches.

Cc: stable@vger.kernel.org
Reported-and-tested-by: syzbot+a93fba6d384346a761e3@syzkaller.appspotmail.com
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/b6568f7beae702bbc236a545d3c020106ca75eac.1616807117.git.skhan@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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This commit is contained in:

Shuah Khan 2021-03-29 19:36:48 -06:00 • committed by Greg Kroah-Hartman

parent 126ce97d39

commit 68be610c19

3 changed files with 29 additions and 5 deletions

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3

drivers/usb/usbip/usbip_common.h

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1

drivers/usb/usbip/vhci_hcd.c

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30

drivers/usb/usbip/vhci_sysfs.c

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