[PATCH 4.14 56/78] ALSA: fireworks: fix wrong return count shorter than expected by 4 bytes

[Greg Kroah-Hartman]

From: Takashi Sakamoto <o-takashi@xxxxxxxxxxxxx>

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@xxxxxxxxxxxxxxx>
Signed-off-by: Takashi Sakamoto <o-takashi@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20220424102428.21109-1-o-takashi@xxxxxxxxxxxxx
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 sound/firewire/fireworks/fireworks_hwdep.c |    1 +
 1 file changed, 1 insertion(+)

--- a/sound/firewire/fireworks/fireworks_hwdep.c
+++ b/sound/firewire/fireworks/fireworks_hwdep.c
@@ -35,6 +35,7 @@ hwdep_read_resp_buf(struct snd_efw *efw,
 	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);