From: Ido Schimmel idosch@nvidia.com
mainline inclusion from mainline-v5.13-rc1 commit 812fa71f0d967dea7616810f27e98135d410b27e category: bugfix bugzilla: 105860 https://gitee.com/openeuler/kernel/issues/I4DDEL
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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Netfilter tries to reroute mangled packets as a different route might need to be used following the mangling. When this happens, netfilter does not populate the IP protocol, the source port and the destination port in the flow key. Therefore, FIB rules that match on these fields are ignored and packets can be misrouted.
Solve this by dissecting the outer flow and populating the flow key before rerouting the packet. Note that flow dissection only happens when FIB rules that match on these fields are installed, so in the common case there should not be a penalty.
Reported-by: Michal Soltys msoltyspl@yandex.pl Signed-off-by: Ido Schimmel idosch@nvidia.com Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Huang Guobin huangguobin4@huawei.com Reviewed-by: Yue Haibing yuehaibing@huawei.com Signed-off-by: Chen Jun chenjun102@huawei.com --- net/ipv4/netfilter.c | 2 ++ net/ipv6/netfilter.c | 2 ++ 2 files changed, 4 insertions(+)
diff --git a/net/ipv4/netfilter.c b/net/ipv4/netfilter.c index 7c841037c533..aff707988e23 100644 --- a/net/ipv4/netfilter.c +++ b/net/ipv4/netfilter.c @@ -25,6 +25,7 @@ int ip_route_me_harder(struct net *net, struct sock *sk, struct sk_buff *skb, un __be32 saddr = iph->saddr; __u8 flags; struct net_device *dev = skb_dst(skb)->dev; + struct flow_keys flkeys; unsigned int hh_len;
sk = sk_to_full_sk(sk); @@ -48,6 +49,7 @@ int ip_route_me_harder(struct net *net, struct sock *sk, struct sk_buff *skb, un fl4.flowi4_oif = l3mdev_master_ifindex(dev); fl4.flowi4_mark = skb->mark; fl4.flowi4_flags = flags; + fib4_rules_early_flow_dissect(net, skb, &fl4, &flkeys); rt = ip_route_output_key(net, &fl4); if (IS_ERR(rt)) return PTR_ERR(rt); diff --git a/net/ipv6/netfilter.c b/net/ipv6/netfilter.c index ab9a279dd6d4..6ab710b5a1a8 100644 --- a/net/ipv6/netfilter.c +++ b/net/ipv6/netfilter.c @@ -24,6 +24,7 @@ int ip6_route_me_harder(struct net *net, struct sock *sk_partial, struct sk_buff { const struct ipv6hdr *iph = ipv6_hdr(skb); struct sock *sk = sk_to_full_sk(sk_partial); + struct flow_keys flkeys; unsigned int hh_len; struct dst_entry *dst; int strict = (ipv6_addr_type(&iph->daddr) & @@ -38,6 +39,7 @@ int ip6_route_me_harder(struct net *net, struct sock *sk_partial, struct sk_buff }; int err;
+ fib6_rules_early_flow_dissect(net, skb, &fl6, &flkeys); dst = ip6_route_output(net, sk, &fl6); err = dst->error; if (err) {