diff options
author | Florian Westphal <fw@strlen.de> | 2022-01-07 07:03:22 +0300 |
---|---|---|
committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2022-01-10 01:30:13 +0300 |
commit | 719774377622bc4025d2a74f551b5dc2158c6c30 (patch) | |
tree | 8fbe7d875fbdaf8fcd909f15b230728c8c8b5baa /net/netfilter/nf_conntrack_core.c | |
parent | 613a0c67d12f33dcbeec2836f5fe60d05b4c18c0 (diff) | |
download | linux-719774377622bc4025d2a74f551b5dc2158c6c30.tar.xz |
netfilter: conntrack: convert to refcount_t api
Convert nf_conn reference counting from atomic_t to refcount_t based api.
refcount_t api provides more runtime sanity checks and will warn on
certain constructs, e.g. refcount_inc() on a zero reference count, which
usually indicates use-after-free.
For this reason template allocation is changed to init the refcount to
1, the subsequenct add operations are removed.
Likewise, init_conntrack() is changed to set the initial refcount to 1
instead refcount_inc().
This is safe because the new entry is not (yet) visible to other cpus.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/netfilter/nf_conntrack_core.c')
-rw-r--r-- | net/netfilter/nf_conntrack_core.c | 26 |
1 files changed, 13 insertions, 13 deletions
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c index bed0017cadb0..328d359fcabe 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -585,7 +585,7 @@ struct nf_conn *nf_ct_tmpl_alloc(struct net *net, tmpl->status = IPS_TEMPLATE; write_pnet(&tmpl->ct_net, net); nf_ct_zone_add(tmpl, zone); - atomic_set(&tmpl->ct_general.use, 0); + refcount_set(&tmpl->ct_general.use, 1); return tmpl; } @@ -618,7 +618,7 @@ destroy_conntrack(struct nf_conntrack *nfct) struct nf_conn *ct = (struct nf_conn *)nfct; pr_debug("destroy_conntrack(%p)\n", ct); - WARN_ON(atomic_read(&nfct->use) != 0); + WARN_ON(refcount_read(&nfct->use) != 0); if (unlikely(nf_ct_is_template(ct))) { nf_ct_tmpl_free(ct); @@ -742,7 +742,7 @@ nf_ct_match(const struct nf_conn *ct1, const struct nf_conn *ct2) /* caller must hold rcu readlock and none of the nf_conntrack_locks */ static void nf_ct_gc_expired(struct nf_conn *ct) { - if (!atomic_inc_not_zero(&ct->ct_general.use)) + if (!refcount_inc_not_zero(&ct->ct_general.use)) return; if (nf_ct_should_gc(ct)) @@ -810,7 +810,7 @@ __nf_conntrack_find_get(struct net *net, const struct nf_conntrack_zone *zone, * in, try to obtain a reference and re-check tuple */ ct = nf_ct_tuplehash_to_ctrack(h); - if (likely(atomic_inc_not_zero(&ct->ct_general.use))) { + if (likely(refcount_inc_not_zero(&ct->ct_general.use))) { if (likely(nf_ct_key_equal(h, tuple, zone, net))) goto found; @@ -907,7 +907,7 @@ nf_conntrack_hash_check_insert(struct nf_conn *ct) smp_wmb(); /* The caller holds a reference to this object */ - atomic_set(&ct->ct_general.use, 2); + refcount_set(&ct->ct_general.use, 2); __nf_conntrack_hash_insert(ct, hash, reply_hash); nf_conntrack_double_unlock(hash, reply_hash); NF_CT_STAT_INC(net, insert); @@ -958,7 +958,7 @@ static void __nf_conntrack_insert_prepare(struct nf_conn *ct) { struct nf_conn_tstamp *tstamp; - atomic_inc(&ct->ct_general.use); + refcount_inc(&ct->ct_general.use); ct->status |= IPS_CONFIRMED; /* set conntrack timestamp, if enabled. */ @@ -1351,7 +1351,7 @@ static unsigned int early_drop_list(struct net *net, nf_ct_is_dying(tmp)) continue; - if (!atomic_inc_not_zero(&tmp->ct_general.use)) + if (!refcount_inc_not_zero(&tmp->ct_general.use)) continue; /* kill only if still in same netns -- might have moved due to @@ -1469,7 +1469,7 @@ static void gc_worker(struct work_struct *work) continue; /* need to take reference to avoid possible races */ - if (!atomic_inc_not_zero(&tmp->ct_general.use)) + if (!refcount_inc_not_zero(&tmp->ct_general.use)) continue; if (gc_worker_skip_ct(tmp)) { @@ -1569,7 +1569,7 @@ __nf_conntrack_alloc(struct net *net, /* Because we use RCU lookups, we set ct_general.use to zero before * this is inserted in any list. */ - atomic_set(&ct->ct_general.use, 0); + refcount_set(&ct->ct_general.use, 0); return ct; out: atomic_dec(&cnet->count); @@ -1594,7 +1594,7 @@ void nf_conntrack_free(struct nf_conn *ct) /* A freed object has refcnt == 0, that's * the golden rule for SLAB_TYPESAFE_BY_RCU */ - WARN_ON(atomic_read(&ct->ct_general.use) != 0); + WARN_ON(refcount_read(&ct->ct_general.use) != 0); nf_ct_ext_destroy(ct); kmem_cache_free(nf_conntrack_cachep, ct); @@ -1686,8 +1686,8 @@ init_conntrack(struct net *net, struct nf_conn *tmpl, if (!exp) __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC); - /* Now it is inserted into the unconfirmed list, bump refcount */ - nf_conntrack_get(&ct->ct_general); + /* Now it is inserted into the unconfirmed list, set refcount to 1. */ + refcount_set(&ct->ct_general.use, 1); nf_ct_add_to_unconfirmed_list(ct); local_bh_enable(); @@ -2300,7 +2300,7 @@ get_next_corpse(int (*iter)(struct nf_conn *i, void *data), return NULL; found: - atomic_inc(&ct->ct_general.use); + refcount_inc(&ct->ct_general.use); spin_unlock(lockp); local_bh_enable(); return ct; |