Commit 77654350306a ("take compat TIOC[SG]SERIAL treatment into
tty_compat_ioctl()") changed the compat version of TIOCGSERIAL to start
checking for the presence of the ->set_serial function pointer rather
than ->get_serial.  This appears to be a copy-and-paste error, since
->get_serial is the function pointer that is called as well as the
pointer that is checked by the non-compat version of TIOCGSERIAL.

Fix this by checking the correct function pointer.

Fixes: 77654350306a ("take compat TIOC[SG]SERIAL treatment into tty_compat_ioctl()")
Cc: <stable@vger.kernel.org> # v4.20+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200224182044.234553-3-ebiggers@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit 77654350306a ("take compat TIOC[SG]SERIAL treatment into
tty_compat_ioctl()") changed the compat version of TIOCGSERIAL to start
copying a whole 'serial_struct32' to userspace rather than individual
fields, but failed to initialize all padding and fields -- namely the
hole after the 'iomem_reg_shift' field, and the 'reserved' field.

Fix this by initializing the struct to zero.

[v2: use sizeof, and convert the adjacent line for consistency.]

Reported-by: syzbot+8da9175e28eadcb203ce@syzkaller.appspotmail.com
Fixes: 77654350306a ("take compat TIOC[SG]SERIAL treatment into tty_compat_ioctl()")
Cc: <stable@vger.kernel.org> # v4.20+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200224182044.234553-2-ebiggers@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The current version of the TTY code unlocks the tty_struct(s) before
release_tty() rather than after.  Moreover, tty_unlock_pair() no longer
exists.  Thus, remove the outdated comments regarding tty_unlock_pair().

Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20200224073359.292795-1-ebiggers@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The driver variable is assigned to unconditionally and not used before.
So there is no need to explicitly initialize it at the start of
tty_kopen().

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20191217075040.8020-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Pull tty/serial updates from Greg KH:
 "Here is the "big" tty and serial driver patches for 5.5-rc1.

  It's a bit later in the merge window than normal as I wanted to make
  sure some last-minute patches applied to it were all sane. They seem
  to be :)

  There's a lot of little stuff in here, for the tty core, and for lots
  of serial drivers:

   - reverts of uartlite serial driver patches that were wrong

   - msm-serial driver fixes

   - serial core updates and fixes

   - tty core fixes

   - serial driver dma mapping api changes

   - lots of other tiny fixes and updates for serial drivers

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'tty-5.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (58 commits)
  Revert "serial/8250: Add support for NI-Serial PXI/PXIe+485 devices"
  vcs: prevent write access to vcsu devices
  tty: vt: keyboard: reject invalid keycodes
  tty: don't crash in tty_init_dev when missing tty_port
  serial: stm32: fix clearing interrupt error flags
  tty: Fix Kconfig indentation, continued
  serial: serial_core: Perform NULL checks for break_ctl ops
  tty: remove unused argument from tty_open_by_driver()
  tty: Fix Kconfig indentation
  {tty: serial, nand: onenand}: samsung: rename to fix build warning
  serial: ifx6x60: add missed pm_runtime_disable
  serial: pl011: Fix DMA ->flush_buffer()
  Revert "serial-uartlite: Move the uart register"
  Revert "serial-uartlite: Add get serial id if not provided"
  Revert "serial-uartlite: Do not use static struct uart_driver out of probe()"
  Revert "serial-uartlite: Add runtime support"
  Revert "serial-uartlite: Change logic how console_port is setup"
  Revert "serial-uartlite: Use allocated structure instead of static ones"
  tty: serial: msm_serial: Use dma_request_chan() directly for channel request
  tty: serial: tegra: Use dma_request_chan() directly for channel request
  ...

We currently warn the user when tty->port is not set in tty_init_dev
yet. The warning says that the kernel will crash later. And it really
will only few lines below at:
tty->port->itty = tty;

So be nice and avoid the crash -- return an error instead. And update
the warning.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Link: https://lore.kernel.org/r/20191122101721.7222-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The argument 'inode' passed to tty_open_by_driver() was not being used.
Remove the extra argument.

Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Link: https://lore.kernel.org/r/20191120151709.14148-1-sudipm.mukherjee@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Multiple tty devices are have tty devices that handle the
PPPIOCGUNIT and PPPIOCGCHAN ioctls. To avoid adding a compat_ioctl
handler to each of those, add it directly in tty_compat_ioctl
so we can remove the calls from fs/compat_ioctl.c.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

All users of this call are in socket or tty code, so handling
it there means we can avoid the table entry in fs/compat_ioctl.c.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Eric Dumazet <edumazet@google.com>
Cc: netdev@vger.kernel.org
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Add a helper to match a device by its type and provide wrappers
for {bus/class/driver}_find_device() APIs.

Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Harald Freudenberger <freude@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-usb@vger.kernel.org
Cc: Oliver Neukum <oneukum@suse.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Tomas Winkler <tomas.winkler@intel.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20190723221838.12024-5-suzuki.poulose@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>