Re: [PATCHv4 net] bonding: fix ICMPv6 header handling when receiving IPv6 messages

[Jay Vosburgh <jay.vosburgh@canonical.com>]

Hangbin Liu <liuhangbin@gmail.com> wrote:

>Currently, we get icmp6hdr via function icmp6_hdr(), which needs the skb
>transport header to be set first. But there is no rule to ask driver set
>transport header before netif_receive_skb() and bond_handle_frame(). So
>we will not able to get correct icmp6hdr on some drivers.
>
>Fix this by using skb_header_pointer to get the IPv6 and ICMPV6 headers.
>
>Reported-by: Liang Li <liali@redhat.com>
>Fixes: 4e24be018eb9 ("bonding: add new parameter ns_targets")
>Suggested-by: Eric Dumazet <eric.dumazet@gmail.com>
>Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>

Acked-by: Jay Vosburgh <jay.vosburgh@canonical.com>


>---
>v4: get the full ipv6+icmp6 hdr in case the skb is not lineared
>v3: fix _hdr parameter warning reported by kernel test robot
>v2: use skb_header_pointer() to get icmp6hdr as Jay suggested.
>---
> drivers/net/bonding/bond_main.c | 17 ++++++++++++-----
> 1 file changed, 12 insertions(+), 5 deletions(-)
>
>diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
>index e84c49bf4d0c..f298b9b3eb77 100644
>--- a/drivers/net/bonding/bond_main.c
>+++ b/drivers/net/bonding/bond_main.c
>@@ -3231,16 +3231,23 @@ static int bond_na_rcv(const struct sk_buff *skb, struct bonding *bond,
> 		       struct slave *slave)
> {
> 	struct slave *curr_active_slave, *curr_arp_slave;
>-	struct icmp6hdr *hdr = icmp6_hdr(skb);
> 	struct in6_addr *saddr, *daddr;
>+	struct {
>+		struct ipv6hdr ip6;
>+		struct icmp6hdr icmp6;
>+	} *combined, _combined;
> 
> 	if (skb->pkt_type == PACKET_OTHERHOST ||
>-	    skb->pkt_type == PACKET_LOOPBACK ||
>-	    hdr->icmp6_type != NDISC_NEIGHBOUR_ADVERTISEMENT)
>+	    skb->pkt_type == PACKET_LOOPBACK)
>+		goto out;
>+
>+	combined = skb_header_pointer(skb, 0, sizeof(_combined), &_combined);
>+	if (!combined || combined->ip6.nexthdr != NEXTHDR_ICMP ||
>+	    combined->icmp6.icmp6_type != NDISC_NEIGHBOUR_ADVERTISEMENT)
> 		goto out;
> 
>-	saddr = &ipv6_hdr(skb)->saddr;
>-	daddr = &ipv6_hdr(skb)->daddr;
>+	saddr = &combined->ip6.saddr;
>+	daddr = &combined->ip6.saddr;
> 
> 	slave_dbg(bond->dev, slave->dev, "%s: %s/%d av %d sv %d sip %pI6c tip %pI6c\n",
> 		  __func__, slave->dev->name, bond_slave_state(slave),
>-- 
>2.38.1
>