[PATCH 2/2] usb: gadget: function: rndis: add length check for header

[Griffin Kroah-Hartman]

Add a length check for the rndis header in rndis_rm_hdr, to ensure that
MessageType, MessageLength, DataOffset, and DataLength fields are
present before they are accessed.

Assisted-by: gkh_clanker_2000
Signed-off-by: Griffin Kroah-Hartman <griffin@xxxxxxxxx>
---
 drivers/usb/gadget/function/rndis.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/usb/gadget/function/rndis.c b/drivers/usb/gadget/function/rndis.c
index fe2018ff071a..a2fd239b7ad3 100644
--- a/drivers/usb/gadget/function/rndis.c
+++ b/drivers/usb/gadget/function/rndis.c
@@ -1080,6 +1080,12 @@ int rndis_rm_hdr(struct gether *port,
 	/* tmp points to a struct rndis_packet_msg_type */
 	__le32 *tmp = (void *)skb->data;
 
+	/* Need at least MessageType, MessageLength, DataOffset, DataLength */
+	if (skb->len < 16) {
+		dev_kfree_skb_any(skb);
+		return -EINVAL;
+	}
+
 	/* MessageType, MessageLength */
 	if (cpu_to_le32(RNDIS_MSG_PACKET)
 			!= get_unaligned(tmp++)) {

-- 
2.55.0