From a42b99a6e329654d376b330de057eff87686d890 Mon Sep 17 00:00:00 2001
From: Florian Westphal <fw@strlen.de>
Date: Thu, 19 Dec 2013 18:25:14 +0100
Subject: [PATCH] netfilter: avoid get_random_bytes calls
All these users need an initial seed value for jhash, prandom is
perfectly fine. This avoids draining the entropy pool where
its not strictly required.
nfnetlink_log did not use the random value at all.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
net/netfilter/nfnetlink_log.c | 8 --------
net/netfilter/nft_hash.c | 2 +-
net/netfilter/xt_RATEEST.c | 2 +-
net/netfilter/xt_connlimit.c | 2 +-
net/netfilter/xt_hashlimit.c | 2 +-
net/netfilter/xt_recent.c | 2 +-
6 files changed, 5 insertions(+), 13 deletions(-)
diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c
index 3c4b69e5fe17..7d4254b0dc6b 100644
--- a/net/netfilter/nfnetlink_log.c
+++ b/net/netfilter/nfnetlink_log.c
@@ -28,8 +28,6 @@
#include <linux/proc_fs.h>
#include <linux/security.h>
#include <linux/list.h>
-#include <linux/jhash.h>
-#include <linux/random.h>
#include <linux/slab.h>
#include <net/sock.h>
#include <net/netfilter/nf_log.h>
@@ -75,7 +73,6 @@ struct nfulnl_instance {
};
#define INSTANCE_BUCKETS 16
-static unsigned int hash_init;
static int nfnl_log_net_id __read_mostly;
@@ -1066,11 +1063,6 @@ static int __init nfnetlink_log_init(void)
{
int status = -ENOMEM;
- /* it's not really all that important to have a random value, so
- * we can do this from the init function, even if there hasn't
- * been that much entropy yet */
- get_random_bytes(&hash_init, sizeof(hash_init));
-
netlink_register_notifier(&nfulnl_rtnl_notifier);
status = nfnetlink_subsys_register(&nfulnl_subsys);
if (status < 0) {
diff --git a/net/netfilter/nft_hash.c b/net/netfilter/nft_hash.c
index 3d3f8fce10a5..6aae699aeb46 100644
--- a/net/netfilter/nft_hash.c
+++ b/net/netfilter/nft_hash.c
@@ -164,7 +164,7 @@ static int nft_hash_init(const struct nft_set *set,
unsigned int cnt, i;
if (unlikely(!nft_hash_rnd_initted)) {
- get_random_bytes(&nft_hash_rnd, 4);
+ nft_hash_rnd = prandom_u32();
nft_hash_rnd_initted = true;
}
diff --git a/net/netfilter/xt_RATEEST.c b/net/netfilter/xt_RATEEST.c
index 370adf622cef..190854be7629 100644
--- a/net/netfilter/xt_RATEEST.c
+++ b/net/netfilter/xt_RATEEST.c
@@ -100,7 +100,7 @@ static int xt_rateest_tg_checkentry(const struct xt_tgchk_param *par)
int ret;
if (unlikely(!rnd_inited)) {
- get_random_bytes(&jhash_rnd, sizeof(jhash_rnd));
+ jhash_rnd = prandom_u32();
rnd_inited = true;
}
diff --git a/net/netfilter/xt_connlimit.c b/net/netfilter/xt_connlimit.c
index c40b2695633b..7671e8214919 100644
--- a/net/netfilter/xt_connlimit.c
+++ b/net/netfilter/xt_connlimit.c
@@ -229,7 +229,7 @@ static int connlimit_mt_check(const struct xt_mtchk_param *par)
u_int32_t rand;
do {
- get_random_bytes(&rand, sizeof(rand));
+ rand = prandom_u32();
} while (!rand);
cmpxchg(&connlimit_rnd, 0, rand);
}
diff --git a/net/netfilter/xt_hashlimit.c b/net/netfilter/xt_hashlimit.c
index 9ff035c71403..a83a35c81150 100644
--- a/net/netfilter/xt_hashlimit.c
+++ b/net/netfilter/xt_hashlimit.c
@@ -177,7 +177,7 @@ dsthash_alloc_init(struct xt_hashlimit_htable *ht,
/* initialize hash with random val at the time we allocate
* the first hashtable entry */
if (unlikely(!ht->rnd_initialized)) {
- get_random_bytes(&ht->rnd, sizeof(ht->rnd));
+ ht->rnd = prandom_u32();
ht->rnd_initialized = true;
}
diff --git a/net/netfilter/xt_recent.c b/net/netfilter/xt_recent.c
index 1e657cf715c4..bfdc29f1a04a 100644
--- a/net/netfilter/xt_recent.c
+++ b/net/netfilter/xt_recent.c
@@ -334,7 +334,7 @@ static int recent_mt_check(const struct xt_mtchk_param *par,
size_t sz;
if (unlikely(!hash_rnd_inited)) {
- get_random_bytes(&hash_rnd, sizeof(hash_rnd));
+ hash_rnd = prandom_u32();
hash_rnd_inited = true;
}
if (info->check_set & ~XT_RECENT_VALID_FLAGS) {
--
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