linux-stable.git/drivers/tty/vt, branch linux-6.15.y

vt: add missing notification when switching back to text mode

2025-07-17T16:44:03+00:00

[ Upstream commit ff78538e07fa284ce08cbbcb0730daa91ed16722 ]

Programs using poll() on /dev/vcsa to be notified when VT changes occur
were missing one case: the switch from gfx to text mode.

Signed-off-by: Nicolas Pitre 
Link: https://lore.kernel.org/r/9o5ro928-0pp4-05rq-70p4-ro385n21n723@onlyvoer.pbz
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

vt: remove VT_RESIZE and VT_RESIZEX from vt_compat_ioctl()

2025-06-19T13:40:32+00:00

[ Upstream commit c4c7ead7b86c1e7f11c64915b7e5bb6d2e242691 ]

They are listed amon those cmd values that "treat 'arg' as an integer"
which is wrong. They should instead fall into the default case. Probably
nobody ever relied on that code since 2009 but still.

Fixes: e92166517e3c ("tty: handle VT specific compat ioctls in vt driver")
Signed-off-by: Nicolas Pitre 
Reviewed-by: Jiri Slaby 
Link: https://lore.kernel.org/r/pr214s15-36r8-6732-2pop-159nq85o48r7@syhkavp.arg
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

tty: Require CAP_SYS_ADMIN for all usages of TIOCL_SELMOUSEREPORT

2025-04-11T14:59:19+00:00

This requirement was overeagerly loosened in commit 2f83e38a095f
("tty: Permit some TIOCL_SETSEL modes without CAP_SYS_ADMIN"), but as
it turns out,

  (1) the logic I implemented there was inconsistent (apologies!),

  (2) TIOCL_SELMOUSEREPORT might actually be a small security risk
      after all, and

  (3) TIOCL_SELMOUSEREPORT is only meant to be used by the mouse
      daemon (GPM or Consolation), which runs as CAP_SYS_ADMIN
      already.

In more detail:

1. The previous patch has inconsistent logic:

   In commit 2f83e38a095f ("tty: Permit some TIOCL_SETSEL modes
   without CAP_SYS_ADMIN"), we checked for sel_mode ==
   TIOCL_SELMOUSEREPORT, but overlooked that the lower four bits of
   this "mode" parameter were actually used as an additional way to
   pass an argument.  So the patch did actually still require
   CAP_SYS_ADMIN, if any of the mouse button bits are set, but did not
   require it if none of the mouse buttons bits are set.

   This logic is inconsistent and was not intentional.  We should have
   the same policies for using TIOCL_SELMOUSEREPORT independent of the
   value of the "hidden" mouse button argument.

   I sent a separate documentation patch to the man page list with
   more details on TIOCL_SELMOUSEREPORT:
   https://lore.kernel.org/all/20250223091342.35523-2-gnoack3000@gmail.com/

2. TIOCL_SELMOUSEREPORT is indeed a potential security risk which can
   let an attacker simulate "keyboard" input to command line
   applications on the same terminal, like TIOCSTI and some other
   TIOCLINUX "selection mode" IOCTLs.

   By enabling mouse reporting on a terminal and then injecting mouse
   reports through TIOCL_SELMOUSEREPORT, an attacker can simulate
   mouse movements on the same terminal, similar to the TIOCSTI
   keystroke injection attacks that were previously possible with
   TIOCSTI and other TIOCL_SETSEL selection modes.

   Many programs (including libreadline/bash) are then prone to
   misinterpret these mouse reports as normal keyboard input because
   they do not expect input in the X11 mouse protocol form.  The
   attacker does not have complete control over the escape sequence,
   but they can at least control the values of two consecutive bytes
   in the binary mouse reporting escape sequence.

   I went into more detail on that in the discussion at
   https://lore.kernel.org/all/20250221.0a947528d8f3@gnoack.org/

   It is not equally trivial to simulate arbitrary keystrokes as it
   was with TIOCSTI (commit 83efeeeb3d04 ("tty: Allow TIOCSTI to be
   disabled")), but the general mechanism is there, and together with
   the small number of existing legit use cases (see below), it would
   be better to revert back to requiring CAP_SYS_ADMIN for
   TIOCL_SELMOUSEREPORT, as it was already the case before
   commit 2f83e38a095f ("tty: Permit some TIOCL_SETSEL modes without
   CAP_SYS_ADMIN").

3. TIOCL_SELMOUSEREPORT is only used by the mouse daemons (GPM or
   Consolation), and they are the only legit use case:

   To quote console_codes(4):

     The mouse tracking facility is intended to return
     xterm(1)-compatible mouse status reports.  Because the console
     driver has no way to know the device or type of the mouse, these
     reports are returned in the console input stream only when the
     virtual terminal driver receives a mouse update ioctl.  These
     ioctls must be generated by a mouse-aware user-mode application
     such as the gpm(8) daemon.

   Jared Finder has also confirmed in
   https://lore.kernel.org/all/491f3df9de6593df8e70dbe77614b026@finder.org/
   that Emacs does not call TIOCL_SELMOUSEREPORT directly, and it
   would be difficult to find good reasons for doing that, given that
   it would interfere with the reports that GPM is sending.

   More information on the interaction between GPM, terminals and the
   kernel with additional pointers is also available in this patch:
   https://lore.kernel.org/all/a773e48920aa104a65073671effbdee665c105fc.1603963593.git.tammo.block@gmail.com/

   For background on who else uses TIOCL_SELMOUSEREPORT: Debian Code
   search finds one page of results, the only two known callers are
   the two mouse daemons GPM and Consolation.  (GPM does not show up
   in the search results because it uses literal numbers to refer to
   TIOCLINUX-related enums.  I looked through GPM by hand instead.
   TIOCL_SELMOUSEREPORT is also not used from libgpm.)
   https://codesearch.debian.net/search?q=TIOCL_SELMOUSEREPORT

Cc: Jared Finder 
Cc: Jann Horn 
Cc: Hanno Böck 
Cc: Jiri Slaby 
Cc: Kees Cook 
Cc: stable 
Fixes: 2f83e38a095f ("tty: Permit some TIOCL_SETSEL modes without CAP_SYS_ADMIN")
Signed-off-by: Günther Noack 
Link: https://lore.kernel.org/r/20250411070144.3959-2-gnoack3000@gmail.com
Signed-off-by: Greg Kroah-Hartman

treewide: Switch/rename to timer_delete[_sync]()

2025-04-05T08:30:12+00:00

timer_delete[_sync]() replaces del_timer[_sync](). Convert the whole tree
over and remove the historical wrapper inlines.

Conversion was done with coccinelle plus manual fixups where necessary.

Signed-off-by: Thomas Gleixner 
Signed-off-by: Ingo Molnar

tty: Permit some TIOCL_SETSEL modes without CAP_SYS_ADMIN

2025-01-13T05:46:50+00:00

With this, processes without CAP_SYS_ADMIN are able to use TIOCLINUX with
subcode TIOCL_SETSEL, in the selection modes TIOCL_SETPOINTER,
TIOCL_SELCLEAR and TIOCL_SELMOUSEREPORT.

TIOCL_SETSEL was previously changed to require CAP_SYS_ADMIN, as this IOCTL
let callers change the selection buffer and could be used to simulate
keypresses.  These three TIOCL_SETSEL selection modes, however, are safe to
use, as they do not modify the selection buffer.

This fixes a mouse support regression that affected Emacs (invisible mouse
cursor).

Cc: stable 
Link: https://lore.kernel.org/r/ee3ec63269b43b34e1c90dd8c9743bf8@finder.org
Fixes: 8d1b43f6a6df ("tty: Restrict access to TIOCLINUX' copy-and-paste subcommands")
Signed-off-by: Günther Noack 
Reviewed-by: Kees Cook 
Link: https://lore.kernel.org/r/20250110142122.1013222-1-gnoack@google.com
Signed-off-by: Greg Kroah-Hartman

vt: prevent kernel-infoleak in con_font_get()

2024-10-11T06:27:36+00:00

font.data may not initialize all memory spaces depending on the implementation
of vc->vc_sw->con_font_get. This may cause info-leak, so to prevent this, it
is safest to modify it to initialize the allocated memory space to 0, and it
generally does not affect the overall performance of the system.

Cc: stable@vger.kernel.org
Reported-by: syzbot+955da2d57931604ee691@syzkaller.appspotmail.com
Fixes: 05e2600cb0a4 ("VT: Bump font size limitation to 64x128 pixels")
Signed-off-by: Jeongjun Park 
Link: https://lore.kernel.org/r/20241010174619.59662-1-aha310510@gmail.com
Signed-off-by: Greg Kroah-Hartman

move asm/unaligned.h to linux/unaligned.h

2024-10-02T21:23:23+00:00

asm/unaligned.h is always an include of asm-generic/unaligned.h;
might as well move that thing to linux/unaligned.h and include
that - there's nothing arch-specific in that header.

auto-generated by the following:

for i in `git grep -l -w asm/unaligned.h`; do
	sed -i -e "s/asm\/unaligned.h/linux\/unaligned.h/" $i
done
for i in `git grep -l -w asm-generic/unaligned.h`; do
	sed -i -e "s/asm-generic\/unaligned.h/linux\/unaligned.h/" $i
done
git mv include/asm-generic/unaligned.h include/linux/unaligned.h
git mv tools/include/asm-generic/unaligned.h tools/include/linux/unaligned.h
sed -i -e "/unaligned.h/d" include/asm-generic/Kbuild
sed -i -e "s/__ASM_GENERIC/__LINUX/" include/linux/unaligned.h tools/include/linux/unaligned.h

tty: vt: conmakehash: remove non-portable code printing comment header

2024-08-13T09:06:29+00:00

Commit 6e20753da6bc ("tty: vt: conmakehash: cope with abs_srctree no
longer in env") included , which invoked another
(wrong) patch that tried to address a build error on macOS.

According to the specification [1], the correct header to use PATH_MAX
is .

The minimal fix would be to replace  with .

However, the following commits seem questionable to me:

 - 3bd85c6c97b2 ("tty: vt: conmakehash: Don't mention the full path of the input in output")
 - 6e20753da6bc ("tty: vt: conmakehash: cope with abs_srctree no longer in env")

These commits made too many efforts to cope with a comment header in
drivers/tty/vt/consolemap_deftbl.c:

  /*
   * Do not edit this file; it was automatically generated by
   *
   * conmakehash drivers/tty/vt/cp437.uni > [this file]
   *
   */

With this commit, the header part of the generate C file will be
simplified as follows:

  /*
   * Automatically generated file; Do not edit.
   */

BTW, another series of excessive efforts for a comment header can be
seen in the following:

 - 5ef6dc08cfde ("lib/build_OID_registry: don't mention the full path of the script in output")
 - 2fe29fe94563 ("lib/build_OID_registry: avoid non-destructive substitution for Perl < 5.13.2 compat")

[1]: https://pubs.opengroup.org/onlinepubs/009695399/basedefs/limits.h.html

Fixes: 6e20753da6bc ("tty: vt: conmakehash: cope with abs_srctree no longer in env")
Cc: stable 
Reported-by: Daniel Gomez 
Closes: https://lore.kernel.org/all/20240807-macos-build-support-v1-11-4cd1ded85694@samsung.com/
Signed-off-by: Masahiro Yamada 
Link: https://lore.kernel.org/r/20240809160853.1269466-1-masahiroy@kernel.org
Signed-off-by: Greg Kroah-Hartman

tty: vt: conmakehash: cope with abs_srctree no longer in env

2024-07-31T10:31:32+00:00

conmakehash uses getenv("abs_srctree") from the environment to strip
the absolute path from the generated sources.
However since commit e2bad142bb3d ("kbuild: unexport abs_srctree and
abs_objtree") this environment variable no longer gets set.
Instead use basename() to indicate the used file in a comment of the
generated source file.

Fixes: 3bd85c6c97b2 ("tty: vt: conmakehash: Don't mention the full path of the input in output")
Cc: stable 
Signed-off-by: Max Krummenacher 
Link: https://lore.kernel.org/stable/20240725132056.9151-1-max.oss.09%40gmail.com
Link: https://lore.kernel.org/r/20240725132056.9151-1-max.oss.09@gmail.com
Signed-off-by: Greg Kroah-Hartman

vt: keyboard: Use led_set_brightness() in LED trigger activate() callback

2024-06-04T12:00:53+00:00

A LED trigger's activate() callback gets called when the LED trigger
gets activated for a specific LED, so that the trigger code can ensure
the LED state matches the current state of the trigger condition.

led_trigger_event() is intended for trigger condition state changes and
iterates over _all_ LEDs which are controlled by this trigger changing
the brightness of each of them.

In the activate() case only the brightness of the LED which is being
activated needs to change and that LED is passed as an argument to
activate(), switch to led_set_brightness() to only change the brightness
of the LED being activated.

Signed-off-by: Hans de Goede 
Reviewed-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20240511152030.4848-1-hdegoede@redhat.com
Signed-off-by: Greg Kroah-Hartman