kernel: Backport patch to fix a netfilter contrack related issue.

This fixes the packet drop issue when using suricata on IPFire.

Signed-off-by: Stefan Schantl <stefan.schantl@ipfire.org>
Signed-off-by: Arne Fitzenreiter <arne_f@ipfire.org>

diff --git a/lfs/linux b/lfs/linux
index a9e30714f5404714f8484e6f0fc1c1a62283c69b..a0b28652ddd1c0dbd468cae8fd98270ee3da56c9 100644 (file)
--- a/lfs/linux
+++ b/lfs/linux
@@ -146,6 +146,9 @@ $(TARGET) : $(patsubst %,$(DIR_DL)/%,$(objects))
        # Fix uevent PHYSDEVDRIVER
        cd $(DIR_APP) && patch -Np1 < $(DIR_SRC)/src/patches/linux/linux-2.6.32.27_mcs7830-fix-driver-name.patch
 
+       # Fix for netfilter nf_conntrack: resolve clash for matching conntracks
+       cd $(DIR_APP) && patch -Np1 < $(DIR_SRC)/src/patches/linux/linux-5.0-netfilter-conntrack-resolve-clash.patch
+
 ifeq "$(KCFG)" "-kirkwood"
        cd $(DIR_APP) && patch -Np1 < $(DIR_SRC)/src/patches/linux/linux-4.14.40-kirkwood-dtb.patch
 endif

diff --git a/src/patches/linux/linux-5.0-netfilter-conntrack-resolve-clash.patch b/src/patches/linux/linux-5.0-netfilter-conntrack-resolve-clash.patch
new file mode 100644 (file)
index 0000000..914cd06
--- /dev/null
+++ b/src/patches/linux/linux-5.0-netfilter-conntrack-resolve-clash.patch
@@ -0,0 +1,75 @@
+commit ed07d9a021df6da53456663a76999189badc432a
+Author: Martynas Pumputis <martynas@weave.works>
+Date:   Mon Jul 2 16:52:14 2018 +0200
+
+    netfilter: nf_conntrack: resolve clash for matching conntracks
+    
+    This patch enables the clash resolution for NAT (disabled in
+    "590b52e10d41") if clashing conntracks match (i.e. both tuples are equal)
+    and a protocol allows it.
+    
+    The clash might happen for a connections-less protocol (e.g. UDP) when
+    two threads in parallel writes to the same socket and consequent calls
+    to "get_unique_tuple" return the same tuples (incl. reply tuples).
+    
+    In this case it is safe to perform the resolution, as the losing CT
+    describes the same mangling as the winning CT, so no modifications to
+    the packet are needed, and the result of rules traversal for the loser's
+    packet stays valid.
+    
+    Signed-off-by: Martynas Pumputis <martynas@weave.works>
+    Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
+
+diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
+index 5123e91b1982..4ced7c7102b6 100644
+--- a/net/netfilter/nf_conntrack_core.c
++++ b/net/netfilter/nf_conntrack_core.c
+@@ -632,6 +632,18 @@ nf_ct_key_equal(struct nf_conntrack_tuple_hash *h,
+              net_eq(net, nf_ct_net(ct));
+ }
+ 
++static inline bool
++nf_ct_match(const struct nf_conn *ct1, const struct nf_conn *ct2)
++{
++      return nf_ct_tuple_equal(&ct1->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
++                               &ct2->tuplehash[IP_CT_DIR_ORIGINAL].tuple) &&
++             nf_ct_tuple_equal(&ct1->tuplehash[IP_CT_DIR_REPLY].tuple,
++                               &ct2->tuplehash[IP_CT_DIR_REPLY].tuple) &&
++             nf_ct_zone_equal(ct1, nf_ct_zone(ct2), IP_CT_DIR_ORIGINAL) &&
++             nf_ct_zone_equal(ct1, nf_ct_zone(ct2), IP_CT_DIR_REPLY) &&
++             net_eq(nf_ct_net(ct1), nf_ct_net(ct2));
++}
++
+ /* caller must hold rcu readlock and none of the nf_conntrack_locks */
+ static void nf_ct_gc_expired(struct nf_conn *ct)
+ {
+@@ -825,19 +837,21 @@ static int nf_ct_resolve_clash(struct net *net, struct sk_buff *skb,
+       /* This is the conntrack entry already in hashes that won race. */
+       struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
+       const struct nf_conntrack_l4proto *l4proto;
++      enum ip_conntrack_info oldinfo;
++      struct nf_conn *loser_ct = nf_ct_get(skb, &oldinfo);
+ 
+       l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
+       if (l4proto->allow_clash &&
+-          ((ct->status & IPS_NAT_DONE_MASK) == 0) &&
+           !nf_ct_is_dying(ct) &&
+           atomic_inc_not_zero(&ct->ct_general.use)) {
+-              enum ip_conntrack_info oldinfo;
+-              struct nf_conn *loser_ct = nf_ct_get(skb, &oldinfo);
+-
+-              nf_ct_acct_merge(ct, ctinfo, loser_ct);
+-              nf_conntrack_put(&loser_ct->ct_general);
+-              nf_ct_set(skb, ct, oldinfo);
+-              return NF_ACCEPT;
++              if (((ct->status & IPS_NAT_DONE_MASK) == 0) ||
++                  nf_ct_match(ct, loser_ct)) {
++                      nf_ct_acct_merge(ct, ctinfo, loser_ct);
++                      nf_conntrack_put(&loser_ct->ct_general);
++                      nf_ct_set(skb, ct, oldinfo);
++                      return NF_ACCEPT;
++              }
++              nf_ct_put(ct);
+       }
+       NF_CT_STAT_INC(net, drop);
+       return NF_DROP;