target/linux/generic/pending-6.1/684-net-bridge-fix-corrupted-ethernet-header-on-multicas.patch

   1 From: Felix Fietkau <nbd@nbd.name>
   2 Date: Sun, 5 May 2024 20:36:56 +0200
   3 Subject: [PATCH] net: bridge: fix corrupted ethernet header on
   4  multicast-to-unicast
   5
   6 The change from skb_copy to pskb_copy unfortunately changed the data
   7 copying to omit the ethernet header, since it was pulled before reaching
   8 this point. Fix this by calling __skb_push/pull around pskb_copy.
   9
  10 Fixes: 59c878cbcdd8 ("net: bridge: fix multicast-to-unicast with fraglist GSO")
  11 Signed-off-by: Felix Fietkau <nbd@nbd.name>
  12 ---
  13
  14 --- a/net/bridge/br_forward.c
  15 +++ b/net/bridge/br_forward.c
  16 @@ -253,6 +253,7 @@ static void maybe_deliver_addr(struct ne
  17  {
  18         struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
  19         const unsigned char *src = eth_hdr(skb)->h_source;
  20 +       struct sk_buff *nskb;
  21
  22         if (!should_deliver(p, skb))
  23                 return;
  24 @@ -261,12 +262,16 @@ static void maybe_deliver_addr(struct ne
  25         if (skb->dev == p->dev && ether_addr_equal(src, addr))
  26                 return;
  27
  28 -       skb = pskb_copy(skb, GFP_ATOMIC);
  29 -       if (!skb) {
  30 +       __skb_push(skb, ETH_HLEN);
  31 +       nskb = pskb_copy(skb, GFP_ATOMIC);
  32 +       __skb_pull(skb, ETH_HLEN);
  33 +       if (!nskb) {
  34                 DEV_STATS_INC(dev, tx_dropped);
  35                 return;
  36         }
  37
  38 +       skb = nskb;
  39 +       __skb_pull(skb, ETH_HLEN);
  40         if (!is_broadcast_ether_addr(addr))
  41                 memcpy(eth_hdr(skb)->h_dest, addr, ETH_ALEN);
  42