target/linux/generic/backport-4.14/367-v4.18-netfilter-nf_flow_table-add-missing-condition-for-TC.patch

   1 From: Felix Fietkau <nbd@nbd.name>
   2 Date: Fri, 23 Mar 2018 17:15:22 +0100
   3 Subject: [PATCH] netfilter: nf_flow_table: add missing condition for TCP state
   4  check
   5
   6 Avoid looking at unrelated fields in UDP packets
   7
   8 Signed-off-by: Felix Fietkau <nbd@nbd.name>
   9 ---
  10
  11 --- a/net/netfilter/nf_flow_table_ip.c
  12 +++ b/net/netfilter/nf_flow_table_ip.c
  13 @@ -15,11 +15,14 @@
  14  #include <linux/tcp.h>
  15  #include <linux/udp.h>
  16
  17 -static int nf_flow_tcp_state_check(struct flow_offload *flow,
  18 -                                  struct sk_buff *skb, unsigned int thoff)
  19 +static int nf_flow_state_check(struct flow_offload *flow, int proto,
  20 +                              struct sk_buff *skb, unsigned int thoff)
  21  {
  22         struct tcphdr *tcph;
  23
  24 +       if (proto != IPPROTO_TCP)
  25 +               return 0;
  26 +
  27         if (!pskb_may_pull(skb, thoff + sizeof(*tcph)))
  28                 return -1;
  29
  30 @@ -248,7 +251,7 @@ nf_flow_offload_ip_hook(void *priv, stru
  31                 return NF_DROP;
  32
  33         thoff = ip_hdr(skb)->ihl * 4;
  34 -       if (nf_flow_tcp_state_check(flow, skb, thoff))
  35 +       if (nf_flow_state_check(flow, ip_hdr(skb)->protocol, skb, thoff))
  36                 return NF_ACCEPT;
  37
  38         if (flow->flags & (FLOW_OFFLOAD_SNAT | FLOW_OFFLOAD_DNAT) &&
  39 @@ -460,7 +463,8 @@ nf_flow_offload_ipv6_hook(void *priv, st
  40         if (unlikely(nf_flow_exceeds_mtu(skb, flow->tuplehash[dir].tuple.mtu)))
  41                 return NF_ACCEPT;
  42
  43 -       if (nf_flow_tcp_state_check(flow, skb, sizeof(*ip6h)))
  44 +       if (nf_flow_state_check(flow, ipv6_hdr(skb)->nexthdr, skb,
  45 +                               sizeof(*ip6h)))
  46                 return NF_ACCEPT;
  47
  48         if (skb_try_make_writable(skb, sizeof(*ip6h)))