From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pablo Neira Ayuso Subject: [PATCH 01/12] netfilter: avoid get_random_bytes calls Date: Mon, 6 Jan 2014 00:09:27 +0100 Message-ID: <1388963378-4903-2-git-send-email-pablo@netfilter.org> References: <1388963378-4903-1-git-send-email-pablo@netfilter.org> Cc: davem@davemloft.net To: netfilter-devel@vger.kernel.org Return-path: Received: from mail.us.es ([193.147.175.20]:55958 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751405AbaAEXJ5 (ORCPT ); Sun, 5 Jan 2014 18:09:57 -0500 In-Reply-To: <1388963378-4903-1-git-send-email-pablo@netfilter.org> Sender: netfilter-devel-owner@vger.kernel.org List-ID: From: Florian Westphal 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 Signed-off-by: Pablo Neira Ayuso --- 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 3c4b69e..7d4254b 100644 --- a/net/netfilter/nfnetlink_log.c +++ b/net/netfilter/nfnetlink_log.c @@ -28,8 +28,6 @@ #include #include #include -#include -#include #include #include #include @@ -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 3d3f8fc..6aae699 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 370adf6..190854b 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 c40b269..7671e82 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 9ff035c..a83a35c 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 1e657cf..bfdc29f 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) { -- 1.7.10.4