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authorHelge Deller <deller@gmx.de>2022-06-25 12:56:49 +0200
committerHelge Deller <deller@gmx.de>2022-07-07 10:50:45 +0200
commit65a01e601dbba8b7a51a2677811f70f783766682 (patch)
tree0d8fee001f1711569f1748df1f3bc6a45ee807b8
parent3663a2fb325b8782524f3edb0ae32d6faa615109 (diff)
downloadlwn-65a01e601dbba8b7a51a2677811f70f783766682.tar.gz
lwn-65a01e601dbba8b7a51a2677811f70f783766682.zip
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+
-rw-r--r--drivers/video/fbdev/core/fbcon.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
index c4e91715ef00..a33532564393 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))))