linux-stable.git/drivers/tty/vt, branch linux-5.14.y

tty: Fix out-of-bound vmalloc access in imageblit

2021-10-07T05:53:04+00:00

[ Upstream commit 3b0c406124719b625b1aba431659f5cdc24a982c ]

This issue happens when a userspace program does an ioctl
FBIOPUT_VSCREENINFO passing the fb_var_screeninfo struct
containing only the fields xres, yres, and bits_per_pixel
with values.

If this struct is the same as the previous ioctl, the
vc_resize() detects it and doesn't call the resize_screen(),
leaving the fb_var_screeninfo incomplete. And this leads to
the updatescrollmode() calculates a wrong value to
fbcon_display->vrows, which makes the real_y() return a
wrong value of y, and that value, eventually, causes
the imageblit to access an out-of-bound address value.

To solve this issue I made the resize_screen() be called
even if the screen does not need any resizing, so it will
"fix and fill" the fb_var_screeninfo independently.

Cc: stable  # after 5.15-rc2 is out, give it time to bake
Reported-and-tested-by: syzbot+858dc7a2f7ef07c2c219@syzkaller.appspotmail.com
Signed-off-by: Igor Matheus Andrade Torrente 
Link: https://lore.kernel.org/r/20210628134509.15895-1-igormtorrente@gmail.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

console: consume APC, DM, DCS

2021-09-26T12:10:15+00:00

commit 3a2b2eb55681158d3e3ef464fbf47574cf0c517c upstream.

The Linux console's VT102 implementation already consumes OSC
("Operating System Command") sequences, probably because that's how
palette changes are transmitted.

In addition to OSC, there are three other major clases of ANSI control
strings: APC ("Application Program Command"), PM ("Privacy Message"),
and DCS ("Device Control String").  They are handled similarly to OSC in
terms of termination.

Source: vt100.net

Add three new enumerated states, one for each of these types.  All three
are handled the same way right now--they simply consume input until
terminated.  I hope to expand upon this firmament in the future.  Add
new predicate ansi_control_string(), returning true for any of these
states.  Replace explicit checks against ESosc with calls to this
function.  Transition to these states appropriately from the escape
initiation (ESesc) state.

This was motivated by the following Notcurses bugs:

 https://github.com/dankamongmen/notcurses/issues/2050
 https://github.com/dankamongmen/notcurses/issues/1828
 https://github.com/dankamongmen/notcurses/issues/2069

where standard VT sequences are not consumed by the Linux console.  It's
not necessary that the Linux console *support* these sequences, but it
ought *consume* these well-specified classes of sequences.

Tested by sending a variety of escape sequences to the console, and
verifying that they still worked, or were now properly consumed.
Verified that the escapes were properly terminated at a generic level.
Verified that the Notcurses tools continued to show expected output on
the Linux console, except now without escape bleedthrough.

Link: https://lore.kernel.org/lkml/YSydL0q8iaUfkphg@schwarzgerat.orthanc/
Signed-off-by: nick black 
Cc: Greg Kroah-Hartman 
Cc: Jiri Slaby 
Cc: Tetsuo Handa 
Cc: Daniel Vetter 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

vt: keyboard.c: make console an unsigned int

2021-09-18T11:43:43+00:00

[ Upstream commit 3df15d6f37246d2f12f53d915c41d806289d3d46 ]

The console variable is used everywhere in some fun pointer path and
array indexes and for some reason isn't always declared as unsigned.
This plays havoc with some static analysis tools so mark the variable as
unsigned so we "know" we can not wrap the arrays backwards here.

Cc: Jiri Slaby 
Cc: Andy Shevchenko 
Reported-by: Jordy Zomer 
Link: https://lore.kernel.org/r/20210726134322.2274919-2-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

vt_kdsetmode: extend console locking

2021-09-03T08:24:01+00:00

commit 2287a51ba822384834dafc1c798453375d1107c7 upstream.

As per the long-suffering comment.

Reported-by: Minh Yuan 
Cc: Greg Kroah-Hartman 
Cc: Jiri Slaby 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

Merge 5.13-rc4 into tty-next

2021-05-31T07:44:28+00:00

We need the tty/serial fixes in here as well.

Signed-off-by: Greg Kroah-Hartman

tty: vt: selection: Correct misspelled function sel_loadlut()

2021-05-20T15:05:33+00:00

Fixes the following W=1 kernel build warning(s):

 drivers/tty/vt/selection.c:119: warning: expecting prototype for set loadlut(). Prototype was for sel_loadlut() instead

Cc: Greg Kroah-Hartman 
Cc: Jiri Slaby 
Signed-off-by: Lee Jones 
Link: https://lore.kernel.org/r/20210520121906.3468725-2-lee.jones@linaro.org
Signed-off-by: Greg Kroah-Hartman

tty: vt: always invoke vc->vc_sw->con_resize callback

2021-05-15T15:12:12+00:00

syzbot is reporting OOB write at vga16fb_imageblit() [1], for
resize_screen() from ioctl(VT_RESIZE) returns 0 without checking whether
requested rows/columns fit the amount of memory reserved for the graphical
screen if current mode is KD_GRAPHICS.

----------
  #include 
  #include 
  #include 
  #include 
  #include 
  #include 

  int main(int argc, char *argv[])
  {
        const int fd = open("/dev/char/4:1", O_RDWR);
        struct vt_sizes vt = { 0x4100, 2 };

        ioctl(fd, KDSETMODE, KD_GRAPHICS);
        ioctl(fd, VT_RESIZE, &vt);
        ioctl(fd, KDSETMODE, KD_TEXT);
        return 0;
  }
----------

Allow framebuffer drivers to return -EINVAL, by moving vc->vc_mode !=
KD_GRAPHICS check from resize_screen() to fbcon_resize().

Link: https://syzkaller.appspot.com/bug?extid=1f29e126cf461c4de3b3 [1]
Reported-by: syzbot 
Suggested-by: Linus Torvalds 
Signed-off-by: Tetsuo Handa 
Tested-by: syzbot 
Signed-off-by: Linus Torvalds

vt: Move custom isspace() to its own namespace

2021-05-13T18:38:51+00:00

If by some reason any of the headers will include ctype.h
we will have a name collision. Avoid this by moving isspace()
to the dedicate namespace.

First appearance of the code is in the commit 24a1c2a769cf
("Import 1.1.92").

Reported-by: kernel test robot 
Reviewed-by: Jiri Slaby 
Signed-off-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20210510144947.58270-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman

Merge branch 'resizex' (patches from Maciej)

2021-05-13T18:12:51+00:00

Merge VT_RESIZEX fixes from Maciej Rozycki:
 "I got to the bottom of the issue with VT_RESIZEX recently discussed
  and came up with this small patch series, fixing an additional issue
  that I originally thought might be broken VGA hardware emulation with
  my laptop, which however turned out to be intertwined with the
  original problem and also a regression introduced somewhat later.

  The fix for that because the first patch, and then to make backporting
  feasible I had to put a revert of the offending change from last
  September next, followed by a proper fix for the framebuffer issue
  that change had tried to address.

  See individual change descriptions for details.

  These have been verified with true VGA hardware (a Trident TVGA8900
  ISA video adapter) using various combinations of `svgatextmode' and
  `setfont' command invocations to change both the VT size and the font
  size, and also switching between the text console and X11, both by
  starting/stopping the X server and by switching between VTs.

  All this to ensure bringing the behaviour of VGA text console back to
  correct operation as it used to be with Linux 2.6.18"

* emailed patches from Maciej W. Rozycki :
  vt: Fix character height handling with VT_RESIZEX
  vt_ioctl: Revert VT_RESIZEX parameter handling removal
  vgacon: Record video mode changes with VT_RESIZEX

vt: Fix character height handling with VT_RESIZEX

2021-05-13T18:00:18+00:00

Restore the original intent of the VT_RESIZEX ioctl's `v_clin' parameter
which is the number of pixel rows per character (cell) rather than the
height of the font used.

For framebuffer devices the two values are always the same, because the
former is inferred from the latter one.  For VGA used as a true text
mode device these two parameters are independent from each other: the
number of pixel rows per character is set in the CRT controller, while
font height is in fact hardwired to 32 pixel rows and fonts of heights
below that value are handled by padding their data with blanks when
loaded to hardware for use by the character generator.  One can change
the setting in the CRT controller and it will update the screen contents
accordingly regardless of the font loaded.

The `v_clin' parameter is used by the `vgacon' driver to set the height
of the character cell and then the cursor position within.  Make the
parameter explicit then, by defining a new `vc_cell_height' struct
member of `vc_data', set it instead of `vc_font.height' from `v_clin' in
the VT_RESIZEX ioctl, and then use it throughout the `vgacon' driver
except where actual font data is accessed which as noted above is
independent from the CRTC setting.

This way the framebuffer console driver is free to ignore the `v_clin'
parameter as irrelevant, as it always should have, avoiding any issues
attempts to give the parameter a meaning there could have caused, such
as one that has led to commit 988d0763361b ("vt_ioctl: make VT_RESIZEX
behave like VT_RESIZE"):

 "syzbot is reporting UAF/OOB read at bit_putcs()/soft_cursor() [1][2],
  for vt_resizex() from ioctl(VT_RESIZEX) allows setting font height
  larger than actual font height calculated by con_font_set() from
  ioctl(PIO_FONT). Since fbcon_set_font() from con_font_set() allocates
  minimal amount of memory based on actual font height calculated by
  con_font_set(), use of vt_resizex() can cause UAF/OOB read for font
  data."

The problem first appeared around Linux 2.5.66 which predates our repo
history, but the origin could be identified with the old MIPS/Linux repo
also at: 
as commit 9736a3546de7 ("Merge with Linux 2.5.66."), where VT_RESIZEX
code in `vt_ioctl' was updated as follows:

 		if (clin)
-			video_font_height = clin;
+			vc->vc_font.height = clin;

making the parameter apply to framebuffer devices as well, perhaps due
to the use of "font" in the name of the original `video_font_height'
variable.  Use "cell" in the new struct member then to avoid ambiguity.

References:

[1] https://syzkaller.appspot.com/bug?id=32577e96d88447ded2d3b76d71254fb855245837
[2] https://syzkaller.appspot.com/bug?id=6b8355d27b2b94fb5cedf4655e3a59162d9e48e3

Signed-off-by: Maciej W. Rozycki 
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org # v2.6.12+
Signed-off-by: Linus Torvalds