From 65a01e601dbba8b7a51a2677811f70f783766682 Mon Sep 17 00:00:00 2001 From: Helge Deller <deller@gmx.de> Date: Sat, 25 Jun 2022 12:56:49 +0200 Subject: [PATCH] fbcon: Disallow setting font bigger than screen size Prevent that users set a font size which is bigger than the physical screen. It's unlikely this may happen (because screens are usually much larger than the fonts and each font char is limited to 32x32 pixels), but it may happen on smaller screens/LCD displays. Signed-off-by: Helge Deller <deller@gmx.de> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: stable@vger.kernel.org # v4.14+ --- drivers/video/fbdev/core/fbcon.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c index c4e91715ef006..a335325643935 100644 --- a/drivers/video/fbdev/core/fbcon.c +++ b/drivers/video/fbdev/core/fbcon.c @@ -2469,6 +2469,11 @@ static int fbcon_set_font(struct vc_data *vc, struct console_font *font, if (charcount != 256 && charcount != 512) return -EINVAL; + /* font bigger than screen resolution ? */ + if (w > FBCON_SWAP(info->var.rotate, info->var.xres, info->var.yres) || + h > FBCON_SWAP(info->var.rotate, info->var.yres, info->var.xres)) + return -EINVAL; + /* Make sure drawing engine can handle the font */ if (!(info->pixmap.blit_x & (1 << (font->width - 1))) || !(info->pixmap.blit_y & (1 << (font->height - 1)))) -- GitLab