forked from TencentOS/TencentOS-kernel
31811374b6
[ Upstream commit ec0972adecb391a8d8650832263a4790f3bfb4df ]
syzbot is reporting OOB read at fbcon_resize() [1], for
commit 39b3cffb8cf31117 ("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: 39b3cffb8cf31117 ("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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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|---|---|---|
| .. | ||
| Makefile | ||
| bitblit.c | ||
| cfbcopyarea.c | ||
| cfbfillrect.c | ||
| cfbimgblt.c | ||
| fb_cmdline.c | ||
| fb_ddc.c | ||
| fb_defio.c | ||
| fb_draw.h | ||
| fb_notify.c | ||
| fb_sys_fops.c | ||
| fbcmap.c | ||
| fbcon.c | ||
| fbcon.h | ||
| fbcon_ccw.c | ||
| fbcon_cw.c | ||
| fbcon_rotate.c | ||
| fbcon_rotate.h | ||
| fbcon_ud.c | ||
| fbcvt.c | ||
| fbmem.c | ||
| fbmon.c | ||
| fbsysfs.c | ||
| modedb.c | ||
| softcursor.c | ||
| svgalib.c | ||
| syscopyarea.c | ||
| sysfillrect.c | ||
| sysimgblt.c | ||
| tileblit.c | ||