ALSA: fireworks: fix wrong return count shorter than expected by 4 bytes

commit eb9d84b0ffe39893cb23b0b6712bbe3637fa25fa upstream.

ALSA fireworks driver has a bug in its initial state to return count
shorter than expected by 4 bytes to userspace applications when handling
response frame for Echo Audio Fireworks transaction. It's due to missing
addition of the size for the type of event in ALSA firewire stack.

Fixes: 555e8a8f7f14 ("ALSA: fireworks: Add command/response functionality into hwdep interface")
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20220424102428.21109-1-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/sound/firewire/fireworks/fireworks_hwdep.c b/sound/firewire/fireworks/fireworks_hwdep.c
index e93eb4616c5f40afd1ada95794f3bc090e08bce2..c739173c668f3ce8416647f3accf7880ac28bdbd 100644 (file)
--- a/sound/firewire/fireworks/fireworks_hwdep.c
+++ b/sound/firewire/fireworks/fireworks_hwdep.c
@@ -34,6 +34,7 @@ hwdep_read_resp_buf(struct snd_efw *efw, char __user *buf, long remained,
        type = SNDRV_FIREWIRE_EVENT_EFW_RESPONSE;
        if (copy_to_user(buf, &type, sizeof(type)))
                return -EFAULT;
+       count += sizeof(type);
        remained -= sizeof(type);
        buf += sizeof(type);