From b33ca195cecea478768de353b3ae976c07a65615 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Fri, 14 May 2021 11:06:12 -0700 Subject: [PATCH] vt: don't allow text-mode resizing when in KD_GRAPHICS mode The VT layer itself just keeps track of the underlying text contents just fine, but if the underlying hardware driver has a con_resize() function, we can't just ignore it when in KD_GRAPHICS mode. So just refuse to do a text mode resize if we're not in text mode. Reported-by: Tetsuo Handa Reported-by: syzbot Signed-off-by: Linus Torvalds --- drivers/tty/vt/vt.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c index 01645e87b3d5..f24e627b7402 100644 --- a/drivers/tty/vt/vt.c +++ b/drivers/tty/vt/vt.c @@ -1171,8 +1171,13 @@ static inline int resize_screen(struct vc_data *vc, int width, int height, /* Resizes the resolution of the display adapater */ int err = 0; - if (vc->vc_mode != KD_GRAPHICS && vc->vc_sw->con_resize) + if (vc->vc_sw->con_resize) { + // If we have a resize function but are in KD_GRAPHICS mode, + // we can't actually do a resize and need to error out. + if (vc->vc_mode == KD_GRAPHICS) + return -EINVAL; err = vc->vc_sw->con_resize(vc, width, height, user); + } return err; } -- 2.31.1.365.ga2a05a39c5