stable inclusion
from linux-4.19.243
commit 47cef5937a43a412405ea54ad6e0a91d2890493e
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I50WAS
CVE: CVE-2022-1048

--------------------------------

commit 3c3201f8 upstream.

Like the previous fixes to hw_params and hw_free ioctl races, we need
to paper over the concurrent prepare ioctl calls against hw_params and
hw_free, too.

This patch implements the locking with the existing
runtime->buffer_mutex for prepare ioctls.  Unlike the previous case
for snd_pcm_hw_hw_params() and snd_pcm_hw_free(), snd_pcm_prepare() is
performed to the linked streams, hence the lock can't be applied
simply on the top.  For tracking the lock in each linked substream, we
modify snd_pcm_action_group() slightly and apply the buffer_mutex for
the case stream_lock=false (formerly there was no lock applied)
there.

Cc: <stable@vger.kernel.org>
Reviewed-by: NJaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20220322170720.3529-4-tiwai@suse.deSigned-off-by: NTakashi Iwai <tiwai@suse.de>
[OP: backport to 4.19: adjusted context]
Signed-off-by: NOvidiu Panait <ovidiu.panait@windriver.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NRui Xiang <rui.xiang@huawei.com>
Reviewed-by: Nzhangxiaoxu <zhangxiaoxu5@huawei.com>
Reviewed-by: NXiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: NYongqiang Liu <liuyongqiang13@huawei.com>