On Thu, 9 Sep 2010, Takashi Iwai wrote:
At Thu, 9 Sep 2010 00:11:41 +0200, Dan Carpenter wrote:
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.
Signed-off-by: Dan Carpenter error27@gmail.com
V2: In the first version I made negative values return -EINVAL V3: We shouldn't return -EINVAL for numbers which are too large but just set the next device to -1.
diff --git a/sound/core/rawmidi.c b/sound/core/rawmidi.c index eb68326..df67605 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;We still need to cover the case device == SNDRV_RAWMIDI_DEVICES. Also, device is incremented, so it has to be SNDRV_RAWMIDI_DEVICE - 1. i.e.
if (device >= SNDRV_RAWMIDI_DEVICES) /* next device is -1 */device = SNDRV_RAWMIDI_DEVICES - 1;I applied the fixed patch now.
Maybe a goto to 'device = -1' line from the condition above might be more light (resulted instruction code size) and understandable for this case.
Jaroslav
----- Jaroslav Kysela perex@perex.cz Linux Kernel Sound Maintainer ALSA Project, Red Hat, Inc.