From fb13b263bca28db7b32da4b243aeaac5002cc704 Mon Sep 17 00:00:00 2001 From: Cong Wang Date: Mon, 5 Feb 2018 14:41:45 -0800 Subject: [PATCH] netfilter: xt_RATEEST: acquire xt_rateest_mutex for hash insert commit 7dc68e98757a8eccf8ca7a53a29b896f1eef1f76 upstream. rateest_hash is supposed to be protected by xt_rateest_mutex, and, as suggested by Eric, lookup and insert should be atomic, so we should acquire the xt_rateest_mutex once for both. So introduce a non-locking helper for internal use and keep the locking one for external. Reported-by: Fixes: 5859034d7eb8 ("[NETFILTER]: x_tables: add RATEEST target") Signed-off-by: Cong Wang Reviewed-by: Florian Westphal Reviewed-by: Eric Dumazet Signed-off-by: Pablo Neira Ayuso Signed-off-by: Greg Kroah-Hartman --- net/netfilter/xt_RATEEST.c | 22 +++++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-) diff --git a/net/netfilter/xt_RATEEST.c b/net/netfilter/xt_RATEEST.c index 370adf622cef..a5f6bd1a663e 100644 --- a/net/netfilter/xt_RATEEST.c +++ b/net/netfilter/xt_RATEEST.c @@ -40,23 +40,31 @@ static void xt_rateest_hash_insert(struct xt_rateest *est) hlist_add_head(&est->list, &rateest_hash[h]); } -struct xt_rateest *xt_rateest_lookup(const char *name) +static struct xt_rateest *__xt_rateest_lookup(const char *name) { struct xt_rateest *est; unsigned int h; h = xt_rateest_hash(name); - mutex_lock(&xt_rateest_mutex); hlist_for_each_entry(est, &rateest_hash[h], list) { if (strcmp(est->name, name) == 0) { est->refcnt++; - mutex_unlock(&xt_rateest_mutex); return est; } } - mutex_unlock(&xt_rateest_mutex); + return NULL; } + +struct xt_rateest *xt_rateest_lookup(const char *name) +{ + struct xt_rateest *est; + + mutex_lock(&xt_rateest_mutex); + est = __xt_rateest_lookup(name); + mutex_unlock(&xt_rateest_mutex); + return est; +} EXPORT_SYMBOL_GPL(xt_rateest_lookup); void xt_rateest_put(struct xt_rateest *est) @@ -104,8 +112,10 @@ static int xt_rateest_tg_checkentry(const struct xt_tgchk_param *par) rnd_inited = true; } - est = xt_rateest_lookup(info->name); + mutex_lock(&xt_rateest_mutex); + est = __xt_rateest_lookup(info->name); if (est) { + mutex_unlock(&xt_rateest_mutex); /* * If estimator parameters are specified, they must match the * existing estimator. @@ -143,11 +153,13 @@ static int xt_rateest_tg_checkentry(const struct xt_tgchk_param *par) info->est = est; xt_rateest_hash_insert(est); + mutex_unlock(&xt_rateest_mutex); return 0; err2: kfree(est); err1: + mutex_unlock(&xt_rateest_mutex); return ret; }