ASoC: SOF: control: add size checks for ext_bytes control .put()

Make sure the TLV header and size are consistent before copying from
userspace.

Fixes: c3078f53 ('ASoC: SOF: Add Sound Open Firmware KControl support')
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Link: https://lore.kernel.org/r/20200921110814.2910477-4-kai.vehmanen@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sof/control.c

@@ -300,6 +300,10 @@ int snd_sof_bytes_ext_put(struct snd_kcontrol *kcontrol,
 	const struct snd_ctl_tlv __user *tlvd =
 		(const struct snd_ctl_tlv __user *)binary_data;
 
+	/* make sure we have at least a header */
+	if (size < sizeof(struct snd_ctl_tlv))
+		return -EINVAL;
+
 	/*
 	 * The beginning of bytes data contains a header from where
 	 * the length (as bytes) is needed to know the correct copy
@@ -308,6 +312,13 @@ int snd_sof_bytes_ext_put(struct snd_kcontrol *kcontrol,
 	if (copy_from_user(&header, tlvd, sizeof(const struct snd_ctl_tlv)))
 		return -EFAULT;
 
+	/* make sure TLV info is consistent */
+	if (header.length + sizeof(struct snd_ctl_tlv) > size) {
+		dev_err_ratelimited(scomp->dev, "error: inconsistent TLV, data %d + header %zu > %d\n",
+				    header.length, sizeof(struct snd_ctl_tlv), size);
+		return -EINVAL;
+	}
+
 	/* be->max is coming from topology */
 	if (header.length > be->max) {
 		dev_err_ratelimited(scomp->dev, "error: Bytes data size %d exceeds max %d.\n",