From 3348ef6a6a126706d6a73ed40c18d8033df72783 Mon Sep 17 00:00:00 2001

From: Dan Carpenter <dan.carpenter@oracle.com>

Date: Tue, 14 Aug 2018 12:07:48 +0300

Subject: [PATCH] libertas_tf: prevent underflow in process_cmdrequest()

Git-commit: 3348ef6a6a126706d6a73ed40c18d8033df72783

Patch-mainline: v4.20

References: bsc#1119086

If recvlength is less than MESSAGE_HEADER_LEN (4) we would end up

corrupting memory.

Fixes: c305a19a0d0a ("libertas_tf: usb specific functions")

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

Signed-off-by: Oliver Neukum <oneukum@suse.com>

---

 drivers/net/wireless/marvell/libertas_tf/if_usb.c |    5 +++--

 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/drivers/net/wireless/marvell/libertas_tf/if_usb.c

+++ b/drivers/net/wireless/marvell/libertas_tf/if_usb.c

@@ -603,9 +603,10 @@ static inline void process_cmdrequest(in

 				      struct if_usb_card *cardp,

 				      struct lbtf_private *priv)

 {

-	if (recvlength > LBS_CMD_BUFFER_SIZE) {

+	if (recvlength < MESSAGE_HEADER_LEN ||

+	    recvlength > LBS_CMD_BUFFER_SIZE) {

 		lbtf_deb_usbd(&cardp->udev->dev,

-			     "The receive buffer is too large\n");

+			     "The receive buffer is invalid %d\n", recvlength);

 		kfree_skb(skb);

 		return;

 	}