diff options
| author | Florian Westphal <fw@strlen.de> | 2022-07-07 21:30:56 +0200 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2022-07-21 00:55:39 +0200 |
| commit | f02e7dc4cff80ee882dbc6e207e054f841e4c2e1 (patch) | |
| tree | 7a0230e3e7290b04d7cc41b0acf49a4ffb34d7a5 | |
| parent | 5787db7c905323cb303a7c39d15fb2067e948adf (diff) | |
netfilter: flowtable: prefer refcount_inc
With refcount_inc_not_zero, we'd also need a smp_rmb or similar,
followed by a test of the CONFIRMED bit.
However, the ct pointer is taken from skb->_nfct, its refcount must
not be 0 (else, we'd already have a use-after-free bug).
Use refcount_inc() instead to clarify the ct refcount is expected to
be at least 1.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
| -rw-r--r-- | net/netfilter/nf_flow_table_core.c | 11 |
1 files changed, 3 insertions, 8 deletions
diff --git a/net/netfilter/nf_flow_table_core.c b/net/netfilter/nf_flow_table_core.c index 51c2b1570838..765ac779bfc8 100644 --- a/net/netfilter/nf_flow_table_core.c +++ b/net/netfilter/nf_flow_table_core.c @@ -53,14 +53,14 @@ struct flow_offload *flow_offload_alloc(struct nf_conn *ct) { struct flow_offload *flow; - if (unlikely(nf_ct_is_dying(ct) || - !refcount_inc_not_zero(&ct->ct_general.use))) + if (unlikely(nf_ct_is_dying(ct))) return NULL; flow = kzalloc(sizeof(*flow), GFP_ATOMIC); if (!flow) - goto err_ct_refcnt; + return NULL; + refcount_inc(&ct->ct_general.use); flow->ct = ct; flow_offload_fill_dir(flow, FLOW_OFFLOAD_DIR_ORIGINAL); @@ -72,11 +72,6 @@ struct flow_offload *flow_offload_alloc(struct nf_conn *ct) __set_bit(NF_FLOW_DNAT, &flow->flags); return flow; - -err_ct_refcnt: - nf_ct_put(ct); - - return NULL; } EXPORT_SYMBOL_GPL(flow_offload_alloc); |