From 566f9c9f89337792070b5a6062dff448b3e7977f Mon Sep 17 00:00:00 2001 From: Helge Deller Date: Sat, 30 Jul 2022 20:50:18 +0200 Subject: vt: Clear selection before changing the font When changing the console font with ioctl(KDFONTOP) the new font size can be bigger than the previous font. A previous selection may thus now be outside of the new screen size and thus trigger out-of-bounds accesses to graphics memory if the selection is removed in vc_do_resize(). Prevent such out-of-memory accesses by dropping the selection before the various con_font_set() console handlers are called. Reported-by: syzbot+14b0e8f3fd1612e35350@syzkaller.appspotmail.com Cc: stable Tested-by: Khalid Masum Signed-off-by: Helge Deller Link: https://lore.kernel.org/r/YuV9apZGNmGfjcor@p100 Signed-off-by: Greg Kroah-Hartman --- drivers/tty/vt/vt.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c index ae9c926acd6f..0b669c82ddc9 100644 --- a/drivers/tty/vt/vt.c +++ b/drivers/tty/vt/vt.c @@ -4662,9 +4662,11 @@ static int con_font_set(struct vc_data *vc, struct console_font_op *op) console_lock(); if (vc->vc_mode != KD_TEXT) rc = -EINVAL; - else if (vc->vc_sw->con_font_set) + else if (vc->vc_sw->con_font_set) { + if (vc_is_sel(vc)) + clear_selection(); rc = vc->vc_sw->con_font_set(vc, &font, op->flags); - else + } else rc = -ENOSYS; console_unlock(); kfree(font.data); @@ -4691,9 +4693,11 @@ static int con_font_default(struct vc_data *vc, struct console_font_op *op) console_unlock(); return -EINVAL; } - if (vc->vc_sw->con_font_default) + if (vc->vc_sw->con_font_default) { + if (vc_is_sel(vc)) + clear_selection(); rc = vc->vc_sw->con_font_default(vc, &font, s); - else + } else rc = -ENOSYS; console_unlock(); if (!rc) { -- cgit v1.2.3-59-g8ed1b