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linux-stable/drivers/video
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Tetsuo Handa ec0972adec fbcon: Fix user font detection test at fbcon_resize(). 
syzbot is reporting OOB read at fbcon_resize() [1], for
commit 39b3cffb8c ("fbcon: prevent user font height or width change
 from causing potential out-of-bounds access") is by error using
registered_fb[con2fb_map[vc->vc_num]]->fbcon_par->p->userfont (which was
set to non-zero) instead of fb_display[vc->vc_num].userfont (which remains
zero for that display).

We could remove tricky userfont flag [2], for we can determine it by
comparing address of the font data and addresses of built-in font data.
But since that commit is failing to fix the original OOB read [3], this
patch keeps the change minimal in case we decide to revert altogether.

[1] https://syzkaller.appspot.com/bug?id=ebcbbb6576958a496500fee9cf7aa83ea00b5920
[2] https://syzkaller.appspot.com/text?tag=Patch&x=14030853900000
[3] https://syzkaller.appspot.com/bug?id=6fba8c186d97cf1011ab17660e633b1cc4e080c9

Reported-by: syzbot <syzbot+b38b1ef6edf0c74a8d97@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Fixes: 39b3cffb8c ("fbcon: prevent user font height or width change from causing potential out-of-bounds access")
Cc: George Kennedy <george.kennedy@oracle.com>
Link: https://lore.kernel.org/r/f6e3e611-8704-1263-d163-f52c906a4f06@I-love.SAKURA.ne.jp
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-09-16 14:35:51 +02:00
..
backlight treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
console TTY/Serial patches for 5.9-rc1 2020-08-06 14:56:11 -07:00
fbdev fbcon: Fix user font detection test at fbcon_resize(). 2020-09-16 14:35:51 +02:00
logo .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
display_timing.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 428 2019-06-05 17:37:16 +02:00
hdmi.c drm-misc-next for v5.9: 2020-06-24 15:45:51 +10:00
Kconfig treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Makefile
of_display_timing.c video: of: display_timing: Don't yell if no timing node is present 2019-07-26 16:32:26 +02:00
of_videomode.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 428 2019-06-05 17:37:16 +02:00
vgastate.c Video: vgastate: fixed a spacing coding style 2018-10-08 12:57:35 +02:00
videomode.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 428 2019-06-05 17:37:16 +02:00