sound: oss: midi_synth: check get_user() return value

commit b3390cea upstream.

get_user() may fail, if so return -EFAULT.
Signed-off-by: Kulikov Vasiliy <segooon@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

sound/oss/midi_synth.c

@@ -519,7 +519,9 @@ midi_synth_load_patch(int dev, int format, const char __user *addr,
 	{
 		unsigned char   data;
 
-		get_user(*(unsigned char *) &data, (unsigned char __user *) &((addr)[hdr_size + i]));
+		if (get_user(data,
+		    (unsigned char __user *)(addr + hdr_size + i)))
+			return -EFAULT;
 
 		eox_seen = (i > 0 && data & 0x80);	/* End of sysex */