bonding: fix ICMPv6 header handling when receiving IPv6 messages

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>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Jay Vosburgh <jay.vosburgh@canonical.com>
Link: https://lore.kernel.org/r/20221118034353.1736727-1-liuhangbin@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index e84c49bf4d0c37ff2649bd2baaf737bd84303814..f298b9b3eb77e417f81fe06b3838b340ef56bf86 100644 (file)
--- 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),