netfilter: xt_connlimit: remove connlimit_rnd_inited

A potential race condition when generating connlimit_rnd is also fixed.

Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>

1 files changed, 7 insertions, 4 deletions

diff --git a/net/netfilter/xt_connlimit.c b/net/netfilter/xt_connlimit.c
index da56d6ec13c9..c6d5a83450c9 100644
--- a/net/netfilter/xt_connlimit.c
+++ b/net/netfilter/xt_connlimit.c
@@ -44,7 +44,6 @@ struct xt_connlimit_data {
 };
 
 static u_int32_t connlimit_rnd __read_mostly;
-static bool connlimit_rnd_inited __read_mostly;
 
 static inline unsigned int connlimit_iphash(__be32 addr)
 {
@@ -226,9 +225,13 @@ static int connlimit_mt_check(const struct xt_mtchk_param *par)
         unsigned int i;
         int ret;
 
-        if (unlikely(!connlimit_rnd_inited)) {
-                get_random_bytes(&connlimit_rnd, sizeof(connlimit_rnd));
-                connlimit_rnd_inited = true;
+        if (unlikely(!connlimit_rnd)) {
+                u_int32_t rand;
+
+                do {
+                        get_random_bytes(&rand, sizeof(rand));
+                } while (!rand);
+                cmpxchg(&connlimit_rnd, 0, rand);
         }
         ret = nf_ct_l3proto_try_module_get(par->family);
         if (ret < 0) {