From 76b6bc38d0f310c0ae1b2a2ebabe2947d92c601a Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Thu, 6 Aug 2026 17:32:19 +0200 Subject: ALSA: mpu401: Check card index validity at probe commit f7dcecb92ed192ff5fcf842918fb1aaea84b5bdd upstream. mpu401 driver blindly trusts that the given devptr->id value is within the proper card index range at probe. It's OK for the devices the driver itself creates at the module probe time, but if the device is bound manually via sysfs interface, this could be -1 as "none", and this leads to OOB access for index[] and other parameters. Add a sanity check for the card index and warn/correct it if it's a value out of the range. Cc: stable@vger.kernel.org Signed-off-by: Takashi Iwai Link: https://patch.msgid.link/20260806153227.1460166-3-tiwai@suse.de Signed-off-by: Greg Kroah-Hartman --- sound/drivers/mpu401/mpu401.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/sound/drivers/mpu401/mpu401.c b/sound/drivers/mpu401/mpu401.c index cd01af5fa4ed..d1194e9682b9 100644 --- a/sound/drivers/mpu401/mpu401.c +++ b/sound/drivers/mpu401/mpu401.c @@ -89,6 +89,12 @@ static int snd_mpu401_probe(struct platform_device *devptr) int err; struct snd_card *card; + if (dev < 0 || dev >= SNDRV_CARDS) { + dev_warn(&devptr->dev, + "Invalid card index %d, using default 0\n", dev); + dev = 0; + } + if (port[dev] == SNDRV_AUTO_PORT) { dev_err(&devptr->dev, "specify port\n"); return -EINVAL; -- cgit v1.2.3