parport: Proper fix for array out-of-bounds access

parport: Proper fix for array out-of-bounds access

commit 02ac3a9ef3a18b58d8f3ea2b6e46de657bf6c4f9 upstream.

The recent fix for array out-of-bounds accesses replaced sprintf()
calls blindly with snprintf().  However, since snprintf() returns the
would-be-printed size, not the actually output size, the length
calculation can still go over the given limit.

Use scnprintf() instead of snprintf(), which returns the actually
output letters, for addressing the potential out-of-bounds access
properly.

Fixes: ab11dac93d2d ("dev/parport: fix the array out-of-bounds risk")
Cc: stable@vger.kernel.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20240920103318.19271-1-tiwai@suse.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>