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From: Felix Fietkau <nbd@nbd.name>
Date: Wed, 7 Feb 2018 09:23:25 +0100
Subject: [PATCH] netfilter: nf_flow_offload: fix use-after-free and a resource
leak
flow_offload_del frees the flow, so all associated resource must be
freed before.
Since the ct entry in struct flow_offload_entry was allocated by
flow_offload_alloc, it should be freed by flow_offload_free to take care
of the error handling path when flow_offload_add fails.
While at it, make flow_offload_del static, since it should never be
called directly, only from the gc step
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
--- a/include/net/netfilter/nf_flow_table.h
+++ b/include/net/netfilter/nf_flow_table.h
@@ -90,7 +90,6 @@ struct flow_offload *flow_offload_alloc(
void flow_offload_free(struct flow_offload *flow);
int flow_offload_add(struct nf_flowtable *flow_table, struct flow_offload *flow);
-void flow_offload_del(struct nf_flowtable *flow_table, struct flow_offload *flow);
struct flow_offload_tuple_rhash *flow_offload_lookup(struct nf_flowtable *flow_table,
struct flow_offload_tuple *tuple);
int nf_flow_table_iterate(struct nf_flowtable *flow_table,
--- a/net/netfilter/nf_flow_table.c
+++ b/net/netfilter/nf_flow_table.c
@@ -125,7 +125,9 @@ void flow_offload_free(struct flow_offlo
dst_release(flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_cache);
dst_release(flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_cache);
e = container_of(flow, struct flow_offload_entry, flow);
- kfree(e);
+ nf_ct_delete(e->ct, 0, 0);
+ nf_ct_put(e->ct);
+ kfree_rcu(e, rcu_head);
}
EXPORT_SYMBOL_GPL(flow_offload_free);
@@ -149,11 +151,9 @@ int flow_offload_add(struct nf_flowtable
}
EXPORT_SYMBOL_GPL(flow_offload_add);
-void flow_offload_del(struct nf_flowtable *flow_table,
- struct flow_offload *flow)
+static void flow_offload_del(struct nf_flowtable *flow_table,
+ struct flow_offload *flow)
{
- struct flow_offload_entry *e;
-
rhashtable_remove_fast(&flow_table->rhashtable,
&flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].node,
*flow_table->type->params);
@@ -161,10 +161,8 @@ void flow_offload_del(struct nf_flowtabl
&flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].node,
*flow_table->type->params);
- e = container_of(flow, struct flow_offload_entry, flow);
- kfree_rcu(e, rcu_head);
+ flow_offload_free(flow);
}
-EXPORT_SYMBOL_GPL(flow_offload_del);
struct flow_offload_tuple_rhash *
flow_offload_lookup(struct nf_flowtable *flow_table,
@@ -175,15 +173,6 @@ flow_offload_lookup(struct nf_flowtable
}
EXPORT_SYMBOL_GPL(flow_offload_lookup);
-static void nf_flow_release_ct(const struct flow_offload *flow)
-{
- struct flow_offload_entry *e;
-
- e = container_of(flow, struct flow_offload_entry, flow);
- nf_ct_delete(e->ct, 0, 0);
- nf_ct_put(e->ct);
-}
-
int nf_flow_table_iterate(struct nf_flowtable *flow_table,
void (*iter)(struct flow_offload *flow, void *data),
void *data)
@@ -259,10 +248,8 @@ static int nf_flow_offload_gc_step(struc
flow = container_of(tuplehash, struct flow_offload, tuplehash[0]);
if (nf_flow_has_expired(flow) ||
- nf_flow_is_dying(flow)) {
+ nf_flow_is_dying(flow))
flow_offload_del(flow_table, flow);
- nf_flow_release_ct(flow);
- }
}
out:
rhashtable_walk_stop(&hti);
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