| Message ID | 20240505184239.15002-1-nbd@nbd.name (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 86b29d830ad69eecff25b22dc96c14c6573718e6 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net] net: bridge: fix corrupted ethernet header on multicast-to-unicast | expand |
On 05/05/2024 21:42, Felix Fietkau wrote: > The change from skb_copy to pskb_copy unfortunately changed the data > copying to omit the ethernet header, since it was pulled before reaching > this point. Fix this by calling __skb_push/pull around pskb_copy. > > Fixes: 59c878cbcdd8 ("net: bridge: fix multicast-to-unicast with fraglist GSO") > Signed-off-by: Felix Fietkau <nbd@nbd.name> > --- > net/bridge/br_forward.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c > index d7c35f55bd69..d97064d460dc 100644 > --- a/net/bridge/br_forward.c > +++ b/net/bridge/br_forward.c > @@ -258,6 +258,7 @@ static void maybe_deliver_addr(struct net_bridge_port *p, struct sk_buff *skb, > { > struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev; > const unsigned char *src = eth_hdr(skb)->h_source; > + struct sk_buff *nskb; > > if (!should_deliver(p, skb)) > return; > @@ -266,12 +267,16 @@ static void maybe_deliver_addr(struct net_bridge_port *p, struct sk_buff *skb, > if (skb->dev == p->dev && ether_addr_equal(src, addr)) > return; > > - skb = pskb_copy(skb, GFP_ATOMIC); > - if (!skb) { > + __skb_push(skb, ETH_HLEN); > + nskb = pskb_copy(skb, GFP_ATOMIC); > + __skb_pull(skb, ETH_HLEN); > + if (!nskb) { > DEV_STATS_INC(dev, tx_dropped); > return; > } > > + skb = nskb; > + __skb_pull(skb, ETH_HLEN); > if (!is_broadcast_ether_addr(addr)) > memcpy(eth_hdr(skb)->h_dest, addr, ETH_ALEN); > This dance is getting ugly, but better to have it correct. It'd be nice if you could add a selftest that exercises it. Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Hello: This patch was applied to netdev/net.git (main) by David S. Miller <davem@davemloft.net>: On Sun, 5 May 2024 20:42:38 +0200 you wrote: > The change from skb_copy to pskb_copy unfortunately changed the data > copying to omit the ethernet header, since it was pulled before reaching > this point. Fix this by calling __skb_push/pull around pskb_copy. > > Fixes: 59c878cbcdd8 ("net: bridge: fix multicast-to-unicast with fraglist GSO") > Signed-off-by: Felix Fietkau <nbd@nbd.name> > > [...] Here is the summary with links: - [net] net: bridge: fix corrupted ethernet header on multicast-to-unicast https://git.kernel.org/netdev/net/c/86b29d830ad6 You are awesome, thank you!
diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c index d7c35f55bd69..d97064d460dc 100644 --- a/net/bridge/br_forward.c +++ b/net/bridge/br_forward.c @@ -258,6 +258,7 @@ static void maybe_deliver_addr(struct net_bridge_port *p, struct sk_buff *skb, { struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev; const unsigned char *src = eth_hdr(skb)->h_source; + struct sk_buff *nskb; if (!should_deliver(p, skb)) return; @@ -266,12 +267,16 @@ static void maybe_deliver_addr(struct net_bridge_port *p, struct sk_buff *skb, if (skb->dev == p->dev && ether_addr_equal(src, addr)) return; - skb = pskb_copy(skb, GFP_ATOMIC); - if (!skb) { + __skb_push(skb, ETH_HLEN); + nskb = pskb_copy(skb, GFP_ATOMIC); + __skb_pull(skb, ETH_HLEN); + if (!nskb) { DEV_STATS_INC(dev, tx_dropped); return; } + skb = nskb; + __skb_pull(skb, ETH_HLEN); if (!is_broadcast_ether_addr(addr)) memcpy(eth_hdr(skb)->h_dest, addr, ETH_ALEN);
The change from skb_copy to pskb_copy unfortunately changed the data copying to omit the ethernet header, since it was pulled before reaching this point. Fix this by calling __skb_push/pull around pskb_copy. Fixes: 59c878cbcdd8 ("net: bridge: fix multicast-to-unicast with fraglist GSO") Signed-off-by: Felix Fietkau <nbd@nbd.name> --- net/bridge/br_forward.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)