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netfilter: nf_flow_offload: fix use-after-free and a resource leak

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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>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Felix Fietkau 2018-02-07 09:49:02 +01:00 committed by Pablo Neira Ayuso
parent d8ed960058
commit 0ff90b6c20
2 changed files with 7 additions and 21 deletions
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1
include/net/netfilter/nf_flow_table.h
View file

@ -90,7 +90,6 @@ struct flow_offload *flow_offload_alloc(struct nf_conn *ct,
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,

27
net/netfilter/nf_flow_table.c
View file

@ -125,7 +125,9 @@ void flow_offload_free(struct flow_offload *flow)
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 *flow_table, struct flow_offload *flow)
}
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_flowtable *flow_table,
&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 *flow_table,
}
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(struct nf_flowtable *flow_table)
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);