From a42b99a6e329654d376b330de057eff87686d890 Mon Sep 17 00:00:00 2001 From: Florian Westphal 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 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 3c4b69e5fe17..7d4254b0dc6b 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 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) { -- 2.30.2