Re: [PATCH] vt: Clear selection before changing the font
From: Khalid Masum <hidden>
Date: 2022-07-31 11:32:52
Also in:
dri-devel, lkml
On 7/31/22 00:50, Helge Deller wrote:
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. Signed-off-by: Helge Deller <deller@gmx.de>
Tested-by: Khalid Masum <redacted>
quoted hunk ↗ jump to hunk
Reported-by: syzbot+14b0e8f3fd1612e35350@syzkaller.appspotmail.comdiff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c index dfc1f4b445f3..3f09205185a4 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) {