From: Alexander Aring Date: Sat, 14 Jul 2018 16:52:10 +0000 (-0400) Subject: net: 6lowpan: fix reserved space for single frames X-Git-Tag: v4.4.155~47 X-Git-Url: http://git.hungrycats.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4e55d28084cc1c94c62b63ece1eeeeb29dc4941e;p=linux net: 6lowpan: fix reserved space for single frames commit ac74f87c789af40936a80131c4759f3e72579c3a upstream. This patch fixes patch add handling to take care tail and headroom for single 6lowpan frames. We need to be sure we have a skb with the right head and tailroom for single frames. This patch do it by using skb_copy_expand() if head and tailroom is not enough allocated by upper layer. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=195059 Reported-by: David Palma Reported-by: Rabi Narayan Sahoo Cc: stable@vger.kernel.org Signed-off-by: Alexander Aring Signed-off-by: Stefan Schmidt Signed-off-by: Greg Kroah-Hartman --- diff --git a/net/ieee802154/6lowpan/tx.c b/net/ieee802154/6lowpan/tx.c index d4353faced35..a10db45b2e1e 100644 --- a/net/ieee802154/6lowpan/tx.c +++ b/net/ieee802154/6lowpan/tx.c @@ -265,9 +265,24 @@ netdev_tx_t lowpan_xmit(struct sk_buff *skb, struct net_device *ldev) /* We must take a copy of the skb before we modify/replace the ipv6 * header as the header could be used elsewhere */ - skb = skb_unshare(skb, GFP_ATOMIC); - if (!skb) - return NET_XMIT_DROP; + if (unlikely(skb_headroom(skb) < ldev->needed_headroom || + skb_tailroom(skb) < ldev->needed_tailroom)) { + struct sk_buff *nskb; + + nskb = skb_copy_expand(skb, ldev->needed_headroom, + ldev->needed_tailroom, GFP_ATOMIC); + if (likely(nskb)) { + consume_skb(skb); + skb = nskb; + } else { + kfree_skb(skb); + return NET_XMIT_DROP; + } + } else { + skb = skb_unshare(skb, GFP_ATOMIC); + if (!skb) + return NET_XMIT_DROP; + } ret = lowpan_header(skb, ldev, &dgram_size, &dgram_offset); if (ret < 0) {