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authorFlorian Westphal <fw@strlen.de>2022-01-07 05:03:22 +0100
committerPablo Neira Ayuso <pablo@netfilter.org>2022-01-09 23:30:13 +0100
commit719774377622bc4025d2a74f551b5dc2158c6c30 (patch)
tree8fbe7d875fbdaf8fcd909f15b230728c8c8b5baa /net/netfilter/nf_conntrack_core.c
parent613a0c67d12f33dcbeec2836f5fe60d05b4c18c0 (diff)
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.c26
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;