diff options
| -rw-r--r-- | net/netfilter/nf_tables_api.c | 3 | ||||
| -rw-r--r-- | net/netfilter/nft_lookup.c | 31 |
2 files changed, 32 insertions, 2 deletions
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 9422b54ab2c2..3028d388b293 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -10467,7 +10467,8 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb) while (++base_seq == 0) ; - WRITE_ONCE(net->nft.base_seq, base_seq); + /* pairs with smp_load_acquire in nft_lookup_eval */ + smp_store_release(&net->nft.base_seq, base_seq); gc_seq = nft_gc_seq_begin(nft_net); diff --git a/net/netfilter/nft_lookup.c b/net/netfilter/nft_lookup.c index 2c6909bf1b40..58c5b14889c4 100644 --- a/net/netfilter/nft_lookup.c +++ b/net/netfilter/nft_lookup.c @@ -55,11 +55,40 @@ __nft_set_do_lookup(const struct net *net, const struct nft_set *set, return set->ops->lookup(net, set, key); } +static unsigned int nft_base_seq(const struct net *net) +{ + /* pairs with smp_store_release() in nf_tables_commit() */ + return smp_load_acquire(&net->nft.base_seq); +} + +static bool nft_lookup_should_retry(const struct net *net, unsigned int seq) +{ + return unlikely(seq != nft_base_seq(net)); +} + const struct nft_set_ext * nft_set_do_lookup(const struct net *net, const struct nft_set *set, const u32 *key) { - return __nft_set_do_lookup(net, set, key); + const struct nft_set_ext *ext; + unsigned int base_seq; + + do { + base_seq = nft_base_seq(net); + + ext = __nft_set_do_lookup(net, set, key); + if (ext) + break; + /* No match? There is a small chance that lookup was + * performed in the old generation, but nf_tables_commit() + * already unlinked a (matching) element. + * + * We need to repeat the lookup to make sure that we didn't + * miss a matching element in the new generation. + */ + } while (nft_lookup_should_retry(net, base_seq)); + + return ext; } EXPORT_SYMBOL_GPL(nft_set_do_lookup); |