ALSA: rawmidi: fix the get next midi device ioctl

If we pass in a device which is higher than SNDRV_RAWMIDI_DEVICES then
the "next device" should be -1.  This function just returns device + 1.

But the main thing is that "device + 1" can lead to a (harmless) integer
overflow and that annoys static analysis tools.

[fix the case for device == SNDRV_RAWMIDI_DEVICE by tiwai]

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 2 insertions, 0 deletions

diff --git a/sound/core/rawmidi.c b/sound/core/rawmidi.c
index eb68326c37d4..a7868ad4d530 100644
--- a/sound/core/rawmidi.c
+++ b/sound/core/rawmidi.c
@@ -829,6 +829,8 @@ static int snd_rawmidi_control_ioctl(struct snd_card *card,
                 
                 if (get_user(device, (int __user *)argp))
                         return -EFAULT;
+                if (device >= SNDRV_RAWMIDI_DEVICES) /* next device is -1 */
+                        device = SNDRV_RAWMIDI_DEVICES - 1;
                 mutex_lock(&register_mutex);
                 device = device < 0 ? 0 : device + 1;
                 while (device < SNDRV_RAWMIDI_DEVICES) {