usbip: vudc: Convert snprintf() to sysfs_emit()

Coccinnelle reports a warning
Warning: Use scnprintf or sprintf

Following the advice on kernel documentation
https://www.kernel.org/doc/html/latest/filesystems/sysfs.html

For show(device *...) functions we should only use sysfs_emit() or sysfs_emit_at()
especially when formatting the value to be returned to user space.
Convert snprintf() to sysfs_emit()

Signed-off-by: Jules Irenge <jules.irenge@postgrad.manchester.ac.uk>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/YzhVIaNGdM33pcts@octinomon
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usbip: vudc: Don't enable IRQs prematurely

This code does:

spin_unlock_irq(&udc->ud.lock);
spin_unlock_irqrestore(&udc->lock, flags);

which does not make sense. In theory, the first unlock could enable
IRQs and then the second _irqrestore could disable them again. There
would be a brief momemt where IRQs were enabled improperly.

In real life, however, this function is always called with IRQs enabled
and the bug does not affect runtime.

Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/Yo4hVWcZNYzKEkIQ@kili
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usbip: vudc: fix missing unlock on error in usbip_sockfd_store()

Add the missing unlock before return from function usbip_sockfd_store()
in the error handling case.

Fixes: bd8b82042269 ("usbip: vudc synchronize sysfs code paths")
Reported-by: Hulk Robot <hulkci@huawei.com>
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Ye Bin <yebin10@huawei.com>
Link: https://lore.kernel.org/r/20210408112305.1022247-1-yebin10@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usbip: vudc synchronize sysfs code paths

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.

Use sysfs_lock to protect sysfs paths in vudc.

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/caabcf3fc87bdae970509b5ff32d05bb7ce2fb15.1616807117.git.skhan@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usbip: Fix incorrect double assignment to udc->ud.tcp_rx

Currently udc->ud.tcp_rx is being assigned twice, the second assignment
is incorrect, it should be to udc->ud.tcp_tx instead of rx. Fix this.

Fixes: 46613c9dfa96 ("usbip: fix vudc usbip_sockfd_store races leading to gpf")
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Cc: stable <stable@vger.kernel.org>
Addresses-Coverity: ("Unused value")
Link: https://lore.kernel.org/r/20210311104445.7811-1-colin.king@canonical.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usbip: fix vudc usbip_sockfd_store races leading to gpf

usbip_sockfd_store() is invoked when user requests attach (import)
detach (unimport) usb gadget device from usbip host. vhci_hcd sends
import request and usbip_sockfd_store() exports the device if it is
free for export.

Export and unexport are governed by local state and shared state
- Shared state (usbip device status, sockfd) - sockfd and Device
status are used to determine if stub should be brought up or shut
down. Device status is shared between host and client.
- Local state (tcp_socket, rx and tx thread task_struct ptrs)
A valid tcp_socket controls rx and tx thread operations while the
device is in exported state.
- While the device is exported, device status is marked used and socket,
sockfd, and thread pointers are valid.

Export sequence (stub-up) includes validating the socket and creating
receive (rx) and transmit (tx) threads to talk to the client to provide
access to the exported device. rx and tx threads depends on local and
shared state to be correct and in sync.

Unexport (stub-down) sequence shuts the socket down and stops the rx and
tx threads. Stub-down sequence relies on local and shared states to be
in sync.

There are races in updating the local and shared status in the current
stub-up sequence resulting in crashes. These stem from starting rx and
tx threads before local and global state is updated correctly to be in
sync.

1. Doesn't handle kthread_create() error and saves invalid ptr in local
state that drives rx and tx threads.
2. Updates tcp_socket and sockfd, starts stub_rx and stub_tx threads
before updating usbip_device status to SDEV_ST_USED. This opens up a
race condition between the threads and usbip_sockfd_store() stub up
and down handling.

Fix the above problems:
- Stop using kthread_get_run() macro to create/start threads.
- Create threads and get task struct reference.
- Add kthread_create() failure handling and bail out.
- Hold usbip_device lock to update local and shared states after
creating rx and tx threads.
- Update usbip_device status to SDEV_ST_USED.
- Update usbip_device tcp_socket, sockfd, tcp_rx, and tcp_tx
- Start threads after usbip_device (tcp_socket, sockfd, tcp_rx, tcp_tx,
and status) is complete.

Credit goes to syzbot and Tetsuo Handa for finding and root-causing the
kthread_get_run() improper error handling problem and others. This is a
hard problem to find and debug since the races aren't seen in a normal
case. Fuzzing forces the race window to be small enough for the
kthread_get_run() error path bug and starting threads before updating the
local and shared state bug in the stub-up sequence.

Fixes: 9720b4bc76a83807 ("staging/usbip: convert to kthread")
Cc: stable@vger.kernel.org
Reported-by: syzbot <syzbot+a93fba6d384346a761e3@syzkaller.appspotmail.com>
Reported-by: syzbot <syzbot+bf1a360e305ee719e364@syzkaller.appspotmail.com>
Reported-by: syzbot <syzbot+95ce4b142579611ef0a9@syzkaller.appspotmail.com>
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/b1c08b983ffa185449c9f0f7d1021dc8c8454b60.1615171203.git.skhan@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usbip: fix vudc to check for stream socket

Fix usbip_sockfd_store() to validate the passed in file descriptor is
a stream socket. If the file descriptor passed was a SOCK_DGRAM socket,
sock_recvmsg() can't detect end of stream.

Cc: stable@vger.kernel.org
Suggested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/387a670316002324113ac7ea1e8b53f4085d0c95.1615171203.git.skhan@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

USB: usbip: convert platform driver to use dev_groups

Platform drivers now have the option to have the platform core create
and remove any needed sysfs attribute files. So take advantage of that
and do not register "by hand" any sysfs files.

Cc: Valentina Manea <valentina.manea.m@gmail.com>
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/20190805193636.25560-5-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usbip: vudc: fix null pointer dereference on udc->lock

Currently the driver attempts to spin lock on udc->lock before a NULL
pointer check is performed on udc, hence there is a potential null
pointer dereference on udc->lock. Fix this by moving the null check
on udc before the lock occurs.

Fixes: ea6873a45a22 ("usbip: vudc: Add SysFS infrastructure for VUDC")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Shuah Khan <shuahkh@osg.samsung.com>
Reviewed-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

USB: move many drivers to use DEVICE_ATTR_WO

Instead of "open coding" a DEVICE_ATTR() define, use the
DEVICE_ATTR_WO() macro instead, which does everything properly instead.

This does require a few static functions to be renamed to work properly,
but thanks to a script from Joe Perches, this was easily done.

Reported-by: Joe Perches <joe@perches.com>
Cc: Peter Chen <Peter.Chen@nxp.com>
Cc: Valentina Manea <valentina.manea.m@gmail.com>
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Acked-by: Johan Hovold <johan@kernel.org>
Acked-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

USB: usbip: Remove redundant license text

Now that the SPDX tag is in all USB files, that identifies the license
in a specific and legally-defined manner. So the extra GPL text wording
can be removed as it is no longer needed at all.

This is done on a quest to remove the 700+ different ways that files in
the kernel describe the GPL license text. And there's unneeded stuff
like the address (sometimes incorrect) for the FSF which is never
needed.

No copyright headers or other non-license-description text was removed.

Cc: Valentina Manea <valentina.manea.m@gmail.com>
Acked-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usbip: use monotonic timestamps

This gets rid of the deprecated do_gettimeofday() function in usbip.
The comment above vgadget_get_frame() mentions that it suffers
from issues with the time jumps due to suspend and settimeofday,
so I'm changing it to use ktime_get_ts64() to use monotonic times
that don't have this problem.

I couldn't tell whether we should use CLOCK_MONOTONIC or
CLOCK_MONOTONIC_RAW here, the difference being the exact rate
when correcting for NTP. I picked monotonic time since it doesn't
change the speed to the existing code and should be better
synchronized with other machines we talk to.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

USB: add SPDX identifiers to all remaining files in drivers/usb/

It's good to have SPDX identifiers in all files to make it easier to
audit the kernel tree for correct licenses.

Update the drivers/usb/ and include/linux/usb* files with the correct
SPDX license identifier based on the license text in the file itself.
The SPDX identifier is a legally binding shorthand, which can be used
instead of the full boiler plate text.

This work is based on a script and data from Thomas Gleixner, Philippe
Ombredanne, and Kate Stewart.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Acked-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: usbip: remove null check

The only caller of get_gadget_descs() has already dereferenced udc
before calling this function, so udc can not be NULL at this point of
the code and hence no use of checking it.

Signed-off-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Reviewed-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: usbip: Avoid NULL pointer dereference in case of error

One line above we have checked that udc is NULL so we shouldn't
dereference it while printing error message.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usbip: vudc: make dev_desc attribute binary

We read a struct usb_device_descriptor from it, so make it an actual
binary attribute.

Signed-off-by: Igor Kotrasinski <i.kotrasinsk@gmail.com>
Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Tested-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usbip: vudc: Add SysFS infrastructure for VUDC

Add sysfs attributes to allow controlling vudc from usbip tools.

dev_desc - device descriptor of current gadget. This is required to
be consisten with current usbip protocol and allow to list
exportable devices on given machine.

usbip_sockfd - allows to pass socket to kernel to start usbip transfer.

usbip_status - currnent status of device

This commit is a result of cooperation between Samsung R&D Institute
Poland and Open Operating Systems Student Society at University
of Warsaw (O2S3@UW) consisting of:

Igor Kotrasinski <ikotrasinsk@gmail.com>
Karol Kosik <karo9@interia.eu>
Ewelina Kosmider <3w3lfin@gmail.com>
Dawid Lazarczyk <lazarczyk.dawid@gmail.com>
Piotr Szulc <ps347277@students.mimuw.edu.pl>

Tutor and project owner:
Krzysztof Opasiak <k.opasiak@samsung.com>

Signed-off-by: Igor Kotrasinski <i.kotrasinsk@samsung.com>
Signed-off-by: Karol Kosik <karo9@interia.eu>
[Various bug fixes, improvements and commit msg update]
Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>