Re: [PATCHv3 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 checking the skb length manually and getting icmp6 header based
>on the IPv6 header offset.
>
>Reported-by: Liang Li <liali@redhat.com>
>Fixes: 4e24be018eb9 ("bonding: add new parameter ns_targets")
>Acked-by: Jonathan Toppins <jtoppins@redhat.com>
>Reviewed-by: David Ahern <dsahern@kernel.org>
>Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>

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

>---
>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 | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
>diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
>index e84c49bf4d0c..2c6356232668 100644
>--- a/drivers/net/bonding/bond_main.c
>+++ b/drivers/net/bonding/bond_main.c
>@@ -3231,12 +3231,17 @@ 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;
>+	const struct icmp6hdr *hdr;
>+	struct icmp6hdr _hdr;
> 
> 	if (skb->pkt_type == PACKET_OTHERHOST ||
> 	    skb->pkt_type == PACKET_LOOPBACK ||
>-	    hdr->icmp6_type != NDISC_NEIGHBOUR_ADVERTISEMENT)
>+	    ipv6_hdr(skb)->nexthdr != NEXTHDR_ICMP)
>+		goto out;
>+
>+	hdr = skb_header_pointer(skb, sizeof(struct ipv6hdr), sizeof(_hdr), &_hdr);
>+	if (!hdr || hdr->icmp6_type != NDISC_NEIGHBOUR_ADVERTISEMENT)
> 		goto out;
> 
> 	saddr = &ipv6_hdr(skb)->saddr;
>-- 
>2.38.1
>