ALSA: pcm: Fix UAF in snd_pcm_oss_get_formats()

ALSA: pcm: Fix UAF in snd_pcm_oss_get_formats()

BugLink: http://bugs.launchpad.net/bugs/1757465
commit 01c0b4265cc16bc1f43f475c5944c55c10d5768f upstream.

snd_pcm_oss_get_formats() has an obvious use-after-free around
snd_mask_test() calls, as spotted by syzbot.  The passed format_mask
argument is a pointer to the hw_params object that is freed before the
loop.  What a surprise that it has been present since the original
code of decades ago...

Reported-by: syzbot+4090700a4f13fccaf648@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>