[Devel] [PATCH rh7] net: nf_synproxy: Direct conntrack allocation

[Kirill Tkhai]

Since synproxy conntrack allow_conntrack_allocation() is executed
from pernet init, loading nf_synproxy_core() module allows conntracks
for all nets.

Fix that by direct allocation of synproxy sample conntrack (and do not
allow conntracks from pernet init).

https://jira.sw.ru/browse/PSBM-52218

Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
---
 include/net/netfilter/nf_conntrack.h |    5 +++++
 net/netfilter/nf_conntrack_core.c    |   11 ++++++-----
 net/netfilter/nf_synproxy_core.c     |    3 +--
 3 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h
index b0da003..fefe866 100644
--- a/include/net/netfilter/nf_conntrack.h
+++ b/include/net/netfilter/nf_conntrack.h
@@ -253,6 +253,11 @@ struct nf_conn *nf_conntrack_alloc(struct net *net, u16 zone,
 				   const struct nf_conntrack_tuple *orig,
 				   const struct nf_conntrack_tuple *repl,
 				   gfp_t gfp);
+struct nf_conn *
+__nf_conntrack_alloc(struct net *net, u16 zone,
+		     const struct nf_conntrack_tuple *orig,
+		     const struct nf_conntrack_tuple *repl,
+		     gfp_t gfp, u32 hash, bool can_alloc);
 
 static inline int nf_ct_is_template(const struct nf_conn *ct)
 {
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 15e8479..d46c905 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -832,16 +832,16 @@ void init_nf_conntrack_hash_rnd(void)
 	cmpxchg(&nf_conntrack_hash_rnd, 0, rand);
 }
 
-static struct nf_conn *
+struct nf_conn *
 __nf_conntrack_alloc(struct net *net, u16 zone,
 		     const struct nf_conntrack_tuple *orig,
 		     const struct nf_conntrack_tuple *repl,
-		     gfp_t gfp, u32 hash)
+		     gfp_t gfp, u32 hash, bool can_alloc)
 {
 	unsigned int ct_max = net->ct.max ? net->ct.max : init_net.ct.max;
 	struct nf_conn *ct;
 
-	if (!net->ct.can_alloc) {
+	if (!net->ct.can_alloc && !can_alloc) {
 		/* No rules loaded */
 		return NULL;
 	}
@@ -915,13 +915,14 @@ __nf_conntrack_alloc(struct net *net, u16 zone,
 	return ERR_PTR(-ENOMEM);
 #endif
 }
+EXPORT_SYMBOL_GPL(__nf_conntrack_alloc);
 
 struct nf_conn *nf_conntrack_alloc(struct net *net, u16 zone,
 				   const struct nf_conntrack_tuple *orig,
 				   const struct nf_conntrack_tuple *repl,
 				   gfp_t gfp)
 {
-	return __nf_conntrack_alloc(net, zone, orig, repl, gfp, 0);
+	return __nf_conntrack_alloc(net, zone, orig, repl, gfp, 0, false);
 }
 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
 
@@ -968,7 +969,7 @@ init_conntrack(struct net *net, struct nf_conn *tmpl,
 	}
 
 	ct = __nf_conntrack_alloc(net, zone, tuple, &repl_tuple, GFP_ATOMIC,
-				  hash);
+				  hash, false);
 	if (IS_ERR_OR_NULL(ct))
 		return (struct nf_conntrack_tuple_hash *)ct;
 
diff --git a/net/netfilter/nf_synproxy_core.c b/net/netfilter/nf_synproxy_core.c
index 779e5a6..3184505 100644
--- a/net/netfilter/nf_synproxy_core.c
+++ b/net/netfilter/nf_synproxy_core.c
@@ -353,8 +353,7 @@ static int __net_init synproxy_net_init(struct net *net)
 	int err = -ENOMEM;
 
 	memset(&t, 0, sizeof(t));
-	allow_conntrack_allocation(net);
-	ct = nf_conntrack_alloc(net, 0, &t, &t, GFP_KERNEL);
+	ct = __nf_conntrack_alloc(net, 0, &t, &t, GFP_KERNEL, 0, true);
 	if (IS_ERR(ct)) {
 		err = PTR_ERR(ct);
 		goto err1;