linux-stable.git/drivers/tty/tty_ioctl.c, branch linux-5.10.y

tty: allow TIOCSLCKTRMIOS with CAP_CHECKPOINT_RESTORE

2024-02-23T07:42:14+00:00

[ Upstream commit e0f25b8992345aa5f113da2815f5add98738c611 ]

The capability CAP_CHECKPOINT_RESTORE was introduced to allow non-root
users to checkpoint and restore processes as non-root with CRIU.

This change extends CAP_CHECKPOINT_RESTORE to enable the CRIU option
'--shell-job' as non-root. CRIU's man-page describes the '--shell-job'
option like this:

  Allow one to dump shell jobs. This implies the restored task will
  inherit session and process group ID from the criu itself. This option
  also allows to migrate a single external tty connection, to migrate
  applications like top.

TIOCSLCKTRMIOS can only be done if the process has CAP_SYS_ADMIN and
this change extends it to CAP_SYS_ADMIN or CAP_CHECKPOINT_RESTORE.

With this change it is possible to checkpoint and restore processes
which have a tty connection as non-root if CAP_CHECKPOINT_RESTORE is
set.

Acked-by: Christian Brauner 
Signed-off-by: Adrian Reber 
Acked-by: Andrei Vagin 
Link: https://lore.kernel.org/r/20231208143656.1019-1-areber@redhat.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

tty: change tty_write_lock()'s ndelay parameter to bool

2024-01-25T22:37:54+00:00

[ Upstream commit af815336556df28f800669c58ab3bdad7d786b98 ]

It's a yes-no parameter, so convert it to bool to be obvious.

Signed-off-by: "Jiri Slaby (SUSE)" 
Link: https://lore.kernel.org/r/20230810091510.13006-6-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman 
Stable-dep-of: 66aad7d8d3ec ("usb: cdc-acm: return correct error code on unsupported break")
Signed-off-by: Sasha Levin

tty: Prevent writing chars during tcsetattr TCSADRAIN/FLUSH

2023-05-17T09:48:09+00:00

[ Upstream commit 094fb49a2d0d6827c86d2e0840873e6db0c491d2 ]

If userspace races tcsetattr() with a write, the drained condition
might not be guaranteed by the kernel. There is a race window after
checking Tx is empty before tty_set_termios() takes termios_rwsem for
write. During that race window, more characters can be queued by a
racing writer.

Any ongoing transmission might produce garbage during HW's
->set_termios() call. The intent of TCSADRAIN/FLUSH seems to be
preventing such a character corruption. If those flags are set, take
tty's write lock to stop any writer before performing the lower layer
Tx empty check and wait for the pending characters to be sent (if any).

The initial wait for all-writers-done must be placed outside of tty's
write lock to avoid deadlock which makes it impossible to use
tty_wait_until_sent(). The write lock is retried if a racing write is
detected.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Ilpo Järvinen 
Link: https://lore.kernel.org/r/20230317113318.31327-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

tty: move some tty-only functions to drivers/tty/tty.h

2023-05-17T09:48:09+00:00

[ Upstream commit 9f72cab1596327e1011ab4599c07b165e0fb45db ]

The flow change and restricted_tty_write() logic is internal to the tty
core only, so move it out of the include/linux/tty.h file.

Cc: Jiri Slaby 
Link: https://lore.kernel.org/r/20210408125134.3016837-12-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman 
Stable-dep-of: 094fb49a2d0d ("tty: Prevent writing chars during tcsetattr TCSADRAIN/FLUSH")
Signed-off-by: Sasha Levin

tty: fix return value for unsupported termiox ioctls

2021-05-14T07:50:19+00:00

[ Upstream commit 8871de06ff78e9333d86c87d7071452b690e7c9b ]

Drivers should return -ENOTTY ("Inappropriate I/O control operation")
when an ioctl isn't supported, while -EINVAL is used for invalid
arguments.

Support for termiox was added by commit 1d65b4a088de ("tty: Add
termiox") in 2008 but no driver support ever followed and it was
recently ripped out by commit e0efb3168d34 ("tty: Remove dead termiox
code").

Fix the return value for the unsupported termiox ioctls, which have
always returned -EINVAL, by explicitly returning -ENOTTY rather than
removing them completely and falling back to the default unrecognised-
ioctl handling.

Fixes: 1d65b4a088de ("tty: Add termiox")
Signed-off-by: Johan Hovold 
Link: https://lore.kernel.org/r/20210407095208.31838-4-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

tty: Remove dead termiox code

2021-05-14T07:50:18+00:00

[ Upstream commit e0efb3168d34dc8c8c72718672b8902e40efff8f ]

set_termiox() and the TCGETX handler bail out with -EINVAL immediately
if ->termiox is NULL, but there are no code paths that can set
->termiox to a non-NULL pointer; and no such code paths seem to have
existed since the termiox mechanism was introduced back in
commit 1d65b4a088de ("tty: Add termiox") in v2.6.28.
Similarly, no driver actually implements .set_termiox; and it looks like
no driver ever has.

Delete this dead code; but leave the definition of struct termiox in the
UAPI headers intact.

Signed-off-by: Jann Horn 
Link: https://lore.kernel.org/r/20201203020331.2394754-1-jannh@google.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

treewide: Use fallthrough pseudo-keyword

2020-08-23T22:36:59+00:00

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva

move compat handling of tty ioctls to tty_compat_ioctl()

2018-09-14T15:12:17+00:00

ioctls that are
	* callable only via tty_ioctl()
	* not driver-specific
	* not demand data structure conversions
	* either always need passing arg as is or always demand compat_ptr()
get intercepted in tty_compat_ioctl() from the very beginning and
redirecter to tty_ioctl().  As the result, their entries in fs/compat_ioctl.c
(some of those had been missing, BTW) got removed, as well as
n_tty_compat_ioctl_helper() (now it's never called with any cmd it would accept).

Signed-off-by: Al Viro

tty: add missing const to termios hw-change helper

2018-05-22T08:08:05+00:00

Add missing const qualifiers to the parameters of the termios hw-change
helper, which is used by a few USB serial drivers. This specifically
allows the pl2303 driver to use const arguments in one of its helper as
well.

Cc: Jiri Slaby 
Acked-by: Greg Kroah-Hartman 
Signed-off-by: Johan Hovold

tty: add SPDX identifiers to all remaining files in drivers/tty/

2017-11-08T12:08:12+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/tty files 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: Jiri Slaby 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Michael Ellerman 
Cc: Chris Metcalf 
Cc: Jiri Kosina 
Cc: David Sterba 
Cc: James Hogan 
Cc: Rob Herring 
Cc: Eric Anholt 
Cc: Stefan Wahren 
Cc: Florian Fainelli 
Cc: Ray Jui 
Cc: Scott Branden 
Cc: bcm-kernel-feedback-list@broadcom.com
Cc: "James E.J. Bottomley" 
Cc: Helge Deller 
Cc: Joachim Eastwood 
Cc: Matthias Brugger 
Cc: Masahiro Yamada 
Cc: Tobias Klauser 
Cc: Russell King 
Cc: Vineet Gupta 
Cc: Richard Genoud 
Cc: Alexander Shiyan 
Cc: Baruch Siach 
Cc: "Maciej W. Rozycki" 
Cc: "Uwe Kleine-König" 
Cc: Pat Gefre 
Cc: "Guilherme G. Piccoli" 
Cc: Jason Wessel 
Cc: Vladimir Zapolskiy 
Cc: Sylvain Lemieux 
Cc: Carlo Caione 
Cc: Kevin Hilman 
Cc: Liviu Dudau 
Cc: Sudeep Holla 
Cc: Lorenzo Pieralisi 
Cc: Andy Gross 
Cc: David Brown 
Cc: "Andreas Färber" 
Cc: Kevin Cernekee 
Cc: Laxman Dewangan 
Cc: Thierry Reding 
Cc: Jonathan Hunter 
Cc: Barry Song 
Cc: Patrice Chotard 
Cc: Maxime Coquelin 
Cc: Alexandre Torgue 
Cc: "David S. Miller" 
Cc: Peter Korsgaard 
Cc: Timur Tabi 
Cc: Tony Prisk 
Cc: Michal Simek 
Cc: "Sören Brinkmann" 
Cc: Thomas Gleixner 
Cc: Kate Stewart 
Cc: Philippe Ombredanne 
Cc: Jiri Slaby 
Signed-off-by: Greg Kroah-Hartman