linux-stable.git/drivers/usb/serial/console.c, branch linux-5.4.y

USB: serial: console: fix reported terminal settings

2018-12-05T10:29:10+00:00

The USB-serial console implementation has never reported the actual
terminal settings used. Despite storing the corresponding cflags in its
struct console, these were never honoured on later tty open() where the
tty termios would be left initialised to the driver defaults.

Unlike the serial console implementation, the USB-serial code calls
subdriver open() already at console setup. While calling set_termios()
and write() before open() looks like it could work for some USB-serial
drivers, others definitely do not expect this, so modelling this after
serial core is going to be intrusive, if at all possible.

Instead, use a (renamed) tty helper to save the termios data used at
console setup so that the tty termios reflects the actual terminal
settings after a subsequent tty open().

Note that the calls to tty_init_termios() (tty_driver_install()) and
tty_save_termios() are serialised using the disconnect mutex.

This specifically fixes a regression that was triggered by a recent
change adding software flow control to the pl2303 driver: a getty trying
to disable flow control while leaving the baud rate unchanged would now
also set the baud rate to the driver default (prior to the flow-control
change this had been a noop).

Fixes: 7041d9c3f01b ("USB: serial: pl2303: add support for tx xon/xoff flow control")
Cc: stable 	# 4.18
Cc: Florian Zumbiehl 
Reported-by: Jarkko Nikula 
Tested-by: Jarkko Nikula 
Acked-by: Greg Kroah-Hartman 
Signed-off-by: Johan Hovold

USB: serial: Remove redundant license text

2017-11-04T10:55:38+00:00

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.

Signed-off-by: Greg Kroah-Hartman 
Acked-by: Johan Hovold 
Signed-off-by: Greg Kroah-Hartman

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

2017-11-04T10:48:02+00:00

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 
Cc: Kate Stewart 
Cc: Philippe Ombredanne 
Signed-off-by: Greg Kroah-Hartman 
Acked-by: Felipe Balbi 
Acked-by: Johan Hovold 
Signed-off-by: Greg Kroah-Hartman

USB: serial: console: fix use-after-free after failed setup

2017-10-09T10:33:31+00:00

Make sure to reset the USB-console port pointer when console setup fails
in order to avoid having the struct usb_serial be prematurely freed by
the console code when the device is later disconnected.

Fixes: 73e487fdb75f ("[PATCH] USB console: fix disconnection issues")
Cc: stable 	# 2.6.18
Acked-by: Greg Kroah-Hartman 
Signed-off-by: Johan Hovold

USB: serial: console: fix use-after-free on disconnect

2017-10-09T10:33:04+00:00

A clean-up patch removing two redundant NULL-checks from the console
disconnect handler inadvertently also removed a third check. This could
lead to the struct usb_serial being prematurely freed by the console
code when a driver accepts but does not register any ports for an
interface which also lacks endpoint descriptors.

Fixes: 0e517c93dc02 ("USB: serial: console: clean up sanity checks")
Cc: stable      # 4.11
Reported-by: Andrey Konovalov 
Acked-by: Greg Kroah-Hartman 
Signed-off-by: Johan Hovold

USB: serial: console: clean up sanity checks

2017-02-08T20:20:49+00:00

Drop two redundant NULL checks from usb_serial_console_disconnect().

The usb_serial_console_disconnect function is called from the
USB-serial-device disconnect callback when a device is going away. Hence
there is no need to check for the serial-device pointer being NULL.

The serial-device port pointers are stored in an array that is a member
of the serial struct so the address of the first member of the array
(which the array name decays to) is never NULL either.

Reviewed-by: Greg Kroah-Hartman 
Signed-off-by: Johan Hovold

USB: serial: console: fix uninitialised spinlock

2017-02-08T20:20:25+00:00

Since commit 4a510969374a ("tty: Make tty_files_lock per-tty") a new
tty_struct spin lock is taken in the tty release path, but the
USB-serial-console hack was never updated hence leaving the lock of its
"fake" tty uninitialised. This was eventually detected by lockdep.

Make sure to initialise the new lock also for the fake tty to address
this regression.

Yes, this code is a mess, but cleaning it up is left for another day.

Fixes: 4a510969374a ("tty: Make tty_files_lock per-tty")
Cc: stable 	# 4.6
Reviewed-by: Greg Kroah-Hartman 
Signed-off-by: Johan Hovold

tty: Replace ASYNC_INITIALIZED bit and update atomically

2016-04-30T16:26:55+00:00

Replace ASYNC_INITIALIZED bit in the tty_port::flags field with
TTY_PORT_INITIALIZED bit in the tty_port::iflags field. Introduce helpers
tty_port_set_initialized() and tty_port_initialized() to abstract
atomic bit ops.

Note: the transforms for test_and_set_bit() and test_and_clear_bit()
are unnecessary as the state transitions are already mutually exclusive;
the tty lock prevents concurrent open/close/hangup.

Signed-off-by: Peter Hurley 
Signed-off-by: Greg Kroah-Hartman

tty: Fix tty_init_termios() declaration

2016-01-27T22:28:20+00:00

tty_init_termios() never returns an error; re-declare as void. Remove
unnecessary error handling from callers. Remove extern declarations
of tty_free_termios() and free_tty_struct() and re-declare in file
scope.

Signed-off-by: Peter Hurley 
Acked-by: Johan Hovold 
Signed-off-by: Greg Kroah-Hartman

USB: console: add dummy __module_get

2015-02-26T16:06:39+00:00

Add call to __module_get when initialising the fake tty in
usb_console_setup to match the module_put in release_one_tty.

Note that the tty-driver (i.e. usb-serial core) must be compiled-in to
enable the usb console so the __module_get is essentially a noop as
driver->owner will be null.

Reported-by: Ben Hutchings 
Signed-off-by: Johan Hovold