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Commit eae522ed authored by Helge Deller's avatar Helge Deller Committed by Greg Kroah-Hartman
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fbcon: Disallow setting font bigger than screen size 



commit 65a01e601dbba8b7a51a2677811f70f783766682 upstream.

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: default avatarHelge Deller <deller@gmx.de>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
Cc: stable@vger.kernel.org # v4.14+
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent d14cb7ad

drivers/video/fbdev/core/fbcon.c

+5 −0
Original line number Diff line number Diff line
@@ -2468,6 +2468,11 @@ 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))))