diff options
| author | Cong Wang <xiyou.wangcong@gmail.com> | 2020-02-02 20:30:52 -0800 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2020-02-07 15:53:31 +0100 |
| commit | c4a3922d2d20c710f827d3a115ee338e8d0467df (patch) | |
| tree | bfb9ea05404c15a28bb5cd556bb24bd79b665341 /net/netfilter | |
| parent | 259039fa30457986929a324d769f543c1509987f (diff) | |
netfilter: xt_hashlimit: reduce hashlimit_mutex scope for htable_put()
It is unnecessary to hold hashlimit_mutex for htable_destroy()
as it is already removed from the global hashtable and its
refcount is already zero.
Also, switch hinfo->use to refcount_t so that we don't have
to hold the mutex until it reaches zero in htable_put().
Reported-and-tested-by: syzbot+adf6c6c2be1c3a718121@syzkaller.appspotmail.com
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/netfilter')
| -rw-r--r-- | net/netfilter/xt_hashlimit.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/net/netfilter/xt_hashlimit.c b/net/netfilter/xt_hashlimit.c index bccd47cd7190..cc475a608f81 100644 --- a/net/netfilter/xt_hashlimit.c +++ b/net/netfilter/xt_hashlimit.c @@ -36,6 +36,7 @@ #include <linux/netfilter_ipv6/ip6_tables.h> #include <linux/mutex.h> #include <linux/kernel.h> +#include <linux/refcount.h> #include <uapi/linux/netfilter/xt_hashlimit.h> #define XT_HASHLIMIT_ALL (XT_HASHLIMIT_HASH_DIP | XT_HASHLIMIT_HASH_DPT | \ @@ -114,7 +115,7 @@ struct dsthash_ent { struct xt_hashlimit_htable { struct hlist_node node; /* global list of all htables */ - int use; + refcount_t use; u_int8_t family; bool rnd_initialized; @@ -315,7 +316,7 @@ static int htable_create(struct net *net, struct hashlimit_cfg3 *cfg, for (i = 0; i < hinfo->cfg.size; i++) INIT_HLIST_HEAD(&hinfo->hash[i]); - hinfo->use = 1; + refcount_set(&hinfo->use, 1); hinfo->count = 0; hinfo->family = family; hinfo->rnd_initialized = false; @@ -420,7 +421,7 @@ static struct xt_hashlimit_htable *htable_find_get(struct net *net, hlist_for_each_entry(hinfo, &hashlimit_net->htables, node) { if (!strcmp(name, hinfo->name) && hinfo->family == family) { - hinfo->use++; + refcount_inc(&hinfo->use); return hinfo; } } @@ -429,12 +430,11 @@ static struct xt_hashlimit_htable *htable_find_get(struct net *net, static void htable_put(struct xt_hashlimit_htable *hinfo) { - mutex_lock(&hashlimit_mutex); - if (--hinfo->use == 0) { + if (refcount_dec_and_mutex_lock(&hinfo->use, &hashlimit_mutex)) { hlist_del(&hinfo->node); + mutex_unlock(&hashlimit_mutex); htable_destroy(hinfo); } - mutex_unlock(&hashlimit_mutex); } /* The algorithm used is the Simple Token Bucket Filter (TBF) |