From: Samuel Thibault <samuel.thibault@xxxxxxxxxxxx> commit 2b09d5d364986f724f17001ccfe4126b9b43a0be upstream. blit_x and blit_y are u32, so fbcon currently cannot support fonts larger than 32x32. The 32x32 case also needs shifting an unsigned int, to properly set bit 31, otherwise we get "UBSAN: shift-out-of-bounds in fbcon_set_font", as reported on: http://lore.kernel.org/all/IA1PR07MB98308653E259A6F2CE94A4AFABCE9@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Kernel Branch: 6.2.0-rc5-next-20230124 Kernel config: https://drive.google.com/file/d/1F-LszDAizEEH0ZX0HcSR06v5q8FPl2Uv/view?usp=sharing Reproducer: https://drive.google.com/file/d/1mP1jcLBY7vWCNM60OMf-ogw-urQRjNrm/view?usp=sharing Reported-by: Sanan Hasanov <sanan.hasanov@xxxxxxxxxxxxxxx> Signed-off-by: Samuel Thibault <samuel.thibault@xxxxxxxxxxxx> Fixes: 2d2699d98492 ("fbcon: font setting should check limitation of driver") Cc: stable@xxxxxxxxxxxxxxx Tested-by: Miko Larsson <mikoxyzzz@xxxxxxxxx> Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Helge Deller <deller@xxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/video/fbdev/core/fbcon.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/drivers/video/fbdev/core/fbcon.c +++ b/drivers/video/fbdev/core/fbcon.c @@ -2450,9 +2450,12 @@ static int fbcon_set_font(struct vc_data h > FBCON_SWAP(info->var.rotate, info->var.yres, info->var.xres)) return -EINVAL; + if (font->width > 32 || font->height > 32) + 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)))) + if (!(info->pixmap.blit_x & BIT(font->width - 1)) || + !(info->pixmap.blit_y & BIT(font->height - 1))) return -EINVAL; /* Make sure driver can handle the font length */
