linux-stable.git/drivers/video/fbdev/core, branch v4.19.321

fbmem: Check virtual screen sizes in fb_set_var()

2024-09-04T11:13:08+00:00

commit 6c11df58fd1ac0aefcb3b227f72769272b939e56 upstream.

Verify that the fbdev or drm driver correctly adjusted the virtual
screen sizes. On failure report the failing driver and reject the screen
size change.

Signed-off-by: Helge Deller 
Reviewed-by: Geert Uytterhoeven 
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Hugo SIMELIERE 
Signed-off-by: Greg Kroah-Hartman

fbcon: Prevent that screen size is smaller than font size

2024-09-04T11:13:08+00:00

commit e64242caef18b4a5840b0e7a9bff37abd4f4f933 upstream.

We need to prevent that users configure a screen size which is smaller than the
currently selected font size. Otherwise rendering chars on the screen will
access memory outside the graphics memory region.

This patch adds a new function fbcon_modechange_possible() which
implements this check and which later may be extended with other checks
if necessary.  The new function is called from the FBIOPUT_VSCREENINFO
ioctl handler in fbmem.c, which will return -EINVAL if userspace asked
for a too small screen size.

Signed-off-by: Helge Deller 
Reviewed-by: Geert Uytterhoeven 
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Hugo SIMELIERE 
Signed-off-by: Greg Kroah-Hartman

fbmon: prevent division by zero in fb_videomode_from_videomode()

2024-04-13T10:50:16+00:00

[ Upstream commit c2d953276b8b27459baed1277a4fdd5dd9bd4126 ]

The expression htotal * vtotal can have a zero value on
overflow. It is necessary to prevent division by zero like in
fb_var_to_videomode().

Found by Linux Verification Center (linuxtesting.org) with Svace.

Signed-off-by: Roman Smirnov 
Reviewed-by: Sergey Shtylyov 
Signed-off-by: Helge Deller 
Signed-off-by: Sasha Levin

fbdev: flush deferred work in fb_deferred_io_fsync()

2024-01-25T22:33:37+00:00

commit 15e4c1f462279b4e128f27de48133e0debe9e0df upstream.

The driver's fsync() is supposed to flush any pending operation to
hardware. It is implemented in this driver by cancelling the queued
deferred IO first, then schedule it for "immediate execution" by calling
schedule_delayed_work() again with delay=0. However, setting delay=0
only means the work is scheduled immediately, it does not mean the work
is executed immediately. There is no guarantee that the work is finished
after schedule_delayed_work() returns. After this driver's fsync()
returns, there can still be pending work. Furthermore, if close() is
called by users immediately after fsync(), the pending work gets
cancelled and fsync() may do nothing.

To ensure that the deferred IO completes, use flush_delayed_work()
instead. Write operations to this driver either write to the device
directly, or invoke schedule_delayed_work(); so by flushing the
workqueue, it can be guaranteed that all previous writes make it to the
device.

Fixes: 5e841b88d23d ("fb: fsync() method for deferred I/O flush.")
Cc: stable@vger.kernel.org
Signed-off-by: Nam Cao 
Reviewed-by: Sebastian Andrzej Siewior 
Signed-off-by: Helge Deller 
Signed-off-by: Greg Kroah-Hartman

fbdev: fix potential OOB read in fast_imageblit()

2023-08-30T14:31:52+00:00

[ Upstream commit c2d22806aecb24e2de55c30a06e5d6eb297d161d ]

There is a potential OOB read at fast_imageblit, for
"colortab[(*src >> 4)]" can become a negative value due to
"const char *s = image->data, *src".
This change makes sure the index for colortab always positive
or zero.

Similar commit:
https://patchwork.kernel.org/patch/11746067

Potential bug report:
https://groups.google.com/g/syzkaller-bugs/c/9ubBXKeKXf4/m/k-QXy4UgAAAJ

Signed-off-by: Zhang Shurong 
Cc: stable@vger.kernel.org
Signed-off-by: Helge Deller 
Signed-off-by: Sasha Levin

fbdev: Fix sys_imageblit() for arbitrary image widths

2023-08-30T14:31:52+00:00

[ Upstream commit 61bfcb6a3b981e8f19e044ac8c3de6edbe6caf70 ]

Commit 6f29e04938bf ("fbdev: Improve performance of sys_imageblit()")
broke sys_imageblit() for image width that are not aligned to 8-bit
boundaries. Fix this by handling the trailing pixels on each line
separately. The performance improvements in the original commit do not
regress by this change.

Signed-off-by: Thomas Zimmermann 
Fixes: 6f29e04938bf ("fbdev: Improve performance of sys_imageblit()")
Reviewed-by: Javier Martinez Canillas 
Acked-by: Daniel Vetter 
Tested-by: Geert Uytterhoeven 
Cc: Thomas Zimmermann 
Cc: Javier Martinez Canillas 
Cc: Sam Ravnborg 
Link: https://patchwork.freedesktop.org/patch/msgid/20220313192952.12058-2-tzimmermann@suse.de
Stable-dep-of: c2d22806aecb ("fbdev: fix potential OOB read in fast_imageblit()")
Signed-off-by: Sasha Levin

fbdev: Improve performance of sys_imageblit()

2023-08-30T14:31:52+00:00

[ Upstream commit 6f29e04938bf509fccfad490a74284cf158891ce ]

Improve the performance of sys_imageblit() by manually unrolling
the inner blitting loop and moving some invariants out. The compiler
failed to do this automatically. The resulting binary code was even
slower than the cfb_imageblit() helper, which uses the same algorithm,
but operates on I/O memory.

A microbenchmark measures the average number of CPU cycles
for sys_imageblit() after a stabilizing period of a few minutes
(i7-4790, FullHD, simpledrm, kernel with debugging). The value
for CFB is given as a reference.

  sys_imageblit(), new: 25934 cycles
  sys_imageblit(), old: 35944 cycles
  cfb_imageblit():      30566 cycles

In the optimized case, sys_imageblit() is now ~30% faster than before
and ~20% faster than cfb_imageblit().

v2:
	* move switch out of inner loop (Gerd)
	* remove test for alignment of dst1 (Sam)

Signed-off-by: Thomas Zimmermann 
Reviewed-by: Javier Martinez Canillas 
Acked-by: Sam Ravnborg 
Link: https://patchwork.freedesktop.org/patch/msgid/20220223193804.18636-3-tzimmermann@suse.de
Stable-dep-of: c2d22806aecb ("fbdev: fix potential OOB read in fast_imageblit()")
Signed-off-by: Sasha Levin

fbcon: Fix null-ptr-deref in soft_cursor

2023-06-09T08:24:04+00:00

commit d78bd6cc68276bd57f766f7cb98bfe32c23ab327 upstream.

syzbot repored this bug in the softcursor code:

BUG: KASAN: null-ptr-deref in soft_cursor+0x384/0x6b4 drivers/video/fbdev/core/softcursor.c:70
Read of size 16 at addr 0000000000000200 by task kworker/u4:1/12

CPU: 0 PID: 12 Comm: kworker/u4:1 Not tainted 6.4.0-rc3-syzkaller-geb0f1697d729 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/28/2023
Workqueue: events_power_efficient fb_flashcursor
Call trace:
 dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:233
 show_stack+0x2c/0x44 arch/arm64/kernel/stacktrace.c:240
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106
 print_report+0xe4/0x514 mm/kasan/report.c:465
 kasan_report+0xd4/0x130 mm/kasan/report.c:572
 kasan_check_range+0x264/0x2a4 mm/kasan/generic.c:187
 __asan_memcpy+0x3c/0x84 mm/kasan/shadow.c:105
 soft_cursor+0x384/0x6b4 drivers/video/fbdev/core/softcursor.c:70
 bit_cursor+0x113c/0x1a64 drivers/video/fbdev/core/bitblit.c:377
 fb_flashcursor+0x35c/0x54c drivers/video/fbdev/core/fbcon.c:380
 process_one_work+0x788/0x12d4 kernel/workqueue.c:2405
 worker_thread+0x8e0/0xfe8 kernel/workqueue.c:2552
 kthread+0x288/0x310 kernel/kthread.c:379
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:853

This fix let bit_cursor() bail out early when a font bitmap
isn't available yet.

Signed-off-by: Helge Deller 
Reported-by: syzbot+d910bd780e6efac35869@syzkaller.appspotmail.com
Acked-by: Sam Ravnborg 
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman

fbdev: modedb: Add 1920x1080 at 60 Hz video mode

2023-06-09T08:23:57+00:00

[ Upstream commit c8902258b2b8ecaa1b8d88c312853c5b14c2553d ]

Add typical resolution for Full-HD monitors.

Signed-off-by: Helge Deller 
Signed-off-by: Sasha Levin

fbcon: Check font dimension limits

2023-02-22T11:47:14+00:00

commit 2b09d5d364986f724f17001ccfe4126b9b43a0be upstream.

blit_x and blit_y are u32, so fbcon currently cannot support fonts
larger than 32x32.

The 32x32 case also needs shifting an unsigned int, to properly set bit
31, otherwise we get "UBSAN: shift-out-of-bounds in fbcon_set_font",
as reported on:

http://lore.kernel.org/all/IA1PR07MB98308653E259A6F2CE94A4AFABCE9@IA1PR07MB9830.namprd07.prod.outlook.com
Kernel Branch: 6.2.0-rc5-next-20230124
Kernel config: https://drive.google.com/file/d/1F-LszDAizEEH0ZX0HcSR06v5q8FPl2Uv/view?usp=sharing
Reproducer: https://drive.google.com/file/d/1mP1jcLBY7vWCNM60OMf-ogw-urQRjNrm/view?usp=sharing

Reported-by: Sanan Hasanov 
Signed-off-by: Samuel Thibault 
Fixes: 2d2699d98492 ("fbcon: font setting should check limitation of driver")
Cc: stable@vger.kernel.org
Tested-by: Miko Larsson 
Reviewed-by: Greg Kroah-Hartman 
Signed-off-by: Helge Deller 
Signed-off-by: Greg Kroah-Hartman