gro: Disable frag0 optimization on IPv6 ext headers

[ Upstream commit 57ea52a865144aedbcd619ee0081155e658b6f7d ]

The GRO fast path caches the frag0 address.  This address becomes
invalid if frag0 is modified by pskb_may_pull or its variants.
So whenever that happens we must disable the frag0 optimization.

This is usually done through the combination of gro_header_hard
and gro_header_slow, however, the IPv6 extension header path did
the pulling directly and would continue to use the GRO fast path
incorrectly.

This patch fixes it by disabling the fast path when we enter the
IPv6 extension header path.

Fixes: 78a478d0efd9 ("gro: Inline skb_gro_header and cache frag0 virtual address")
Reported-by: Slava Shwartsman <slavash@mellanox.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 41239f739d515d43fe76a8688fcb1c3394075b61..0a793dcd975fda111edbc6c89c1958ccacf62b98 100644 (file)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1829,14 +1829,19 @@ static inline int skb_gro_header_hard(struct sk_buff *skb, unsigned int hlen)
        return NAPI_GRO_CB(skb)->frag0_len < hlen;
 }
 
+static inline void skb_gro_frag0_invalidate(struct sk_buff *skb)
+{
+       NAPI_GRO_CB(skb)->frag0 = NULL;
+       NAPI_GRO_CB(skb)->frag0_len = 0;
+}
+
 static inline void *skb_gro_header_slow(struct sk_buff *skb, unsigned int hlen,
                                        unsigned int offset)
 {
        if (!pskb_may_pull(skb, hlen))
                return NULL;
 
-       NAPI_GRO_CB(skb)->frag0 = NULL;
-       NAPI_GRO_CB(skb)->frag0_len = 0;
+       skb_gro_frag0_invalidate(skb);
        return skb->data + offset;
 }
 

diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c
index d82de72281009c1b93d1cbde1bac91c023ecd930..1a6ef4c8cd8b767c6a27bcab9ef23b7fa70ab9fc 100644 (file)
--- a/net/ipv6/ip6_offload.c
+++ b/net/ipv6/ip6_offload.c
@@ -177,6 +177,7 @@ static struct sk_buff **ipv6_gro_receive(struct sk_buff **head,
        ops = rcu_dereference(inet6_offloads[proto]);
        if (!ops || !ops->callbacks.gro_receive) {
                __pskb_pull(skb, skb_gro_offset(skb));
+               skb_gro_frag0_invalidate(skb);
                proto = ipv6_gso_pull_exthdrs(skb, proto);
                skb_gro_pull(skb, -skb_transport_offset(skb));
                skb_reset_transport_header(skb);