From: Linyu Yuan <linyyuan@codeaurora.org>
Date: Wed, 16 Jun 2021 23:32:32 +0000 (+0800)
Subject: net: cdc_eem: fix tx fixup skb leak
X-Git-Tag: v4.4.274~29
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f12554b0ff639e74612cc01b3b4a049e098d2d65;p=thirdparty%2Fkernel%2Fstable.git

net: cdc_eem: fix tx fixup skb leak

[ Upstream commit c3b26fdf1b32f91c7a3bc743384b4a298ab53ad7 ]

when usbnet transmit a skb, eem fixup it in eem_tx_fixup(),
if skb_copy_expand() failed, it return NULL,
usbnet_start_xmit() will have no chance to free original skb.

fix it by free orginal skb in eem_tx_fixup() first,
then check skb clone status, if failed, return NULL to usbnet.

Fixes: 9f722c0978b0 ("usbnet: CDC EEM support (v5)")
Signed-off-by: Linyu Yuan <linyyuan@codeaurora.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/drivers/net/usb/cdc_eem.c b/drivers/net/usb/cdc_eem.c
index f7180f8db39e1..9c15e1a1261be 100644
--- a/drivers/net/usb/cdc_eem.c
+++ b/drivers/net/usb/cdc_eem.c
@@ -138,10 +138,10 @@ static struct sk_buff *eem_tx_fixup(struct usbnet *dev, struct sk_buff *skb,
 	}
 
 	skb2 = skb_copy_expand(skb, EEM_HEAD, ETH_FCS_LEN + padlen, flags);
+	dev_kfree_skb_any(skb);
 	if (!skb2)
 		return NULL;
 
-	dev_kfree_skb_any(skb);
 	skb = skb2;
 
 done: