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authorCong Wang <xiyou.wangcong@gmail.com>2018-02-05 14:41:45 -0800
committerPablo Neira Ayuso <pablo@netfilter.org>2018-02-07 00:58:57 +0100
commit7dc68e98757a8eccf8ca7a53a29b896f1eef1f76 (patch)
treed7ccfe10125fd7b843b55579d7ff5b8d11744850 /net
parent992cfc7c5d105094da7c21c9c74d97ac26bb1e56 (diff)
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netfilter: xt_RATEEST: acquire xt_rateest_mutex for hash insert
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: <syzbot+5cb189720978275e4c75@syzkaller.appspotmail.com> Fixes: 5859034d7eb8 ("[NETFILTER]: x_tables: add RATEEST target") Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Reviewed-by: Florian Westphal <fw@strlen.de> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
-rw-r--r--net/netfilter/xt_RATEEST.c22
1 files changed, 17 insertions, 5 deletions
diff --git a/net/netfilter/xt_RATEEST.c b/net/netfilter/xt_RATEEST.c
index 498b54fd04d7..141c295191f6 100644
--- a/net/netfilter/xt_RATEEST.c
+++ b/net/netfilter/xt_RATEEST.c
@@ -39,23 +39,31 @@ 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)
@@ -100,8 +108,10 @@ static int xt_rateest_tg_checkentry(const struct xt_tgchk_param *par)
net_get_random_once(&jhash_rnd, sizeof(jhash_rnd));
- 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.
@@ -139,11 +149,13 @@ 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;
}