From 79e09ef96b6a5fb888f5241f3aa707e9ad0b1cce Mon Sep 17 00:00:00 2001 From: Liping Zhang Date: Mon, 3 Apr 2017 16:34:38 +0800 Subject: [PATCH] netfilter: nft_hash: do not dump the auto generated seed This can prevent the nft utility from printing out the auto generated seed to the user, which is unnecessary and confusing. Fixes: cb1b69b0b15b ("netfilter: nf_tables: add hash expression") Signed-off-by: Liping Zhang Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nft_hash.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/net/netfilter/nft_hash.c b/net/netfilter/nft_hash.c index eb2721af898d..c4dad1254ead 100644 --- a/net/netfilter/nft_hash.c +++ b/net/netfilter/nft_hash.c @@ -21,6 +21,7 @@ struct nft_hash { enum nft_registers sreg:8; enum nft_registers dreg:8; u8 len; + bool autogen_seed:1; u32 modulus; u32 seed; u32 offset; @@ -82,10 +83,12 @@ static int nft_hash_init(const struct nft_ctx *ctx, if (priv->offset + priv->modulus - 1 < priv->offset) return -EOVERFLOW; - if (tb[NFTA_HASH_SEED]) + if (tb[NFTA_HASH_SEED]) { priv->seed = ntohl(nla_get_be32(tb[NFTA_HASH_SEED])); - else + } else { + priv->autogen_seed = true; get_random_bytes(&priv->seed, sizeof(priv->seed)); + } return nft_validate_register_load(priv->sreg, len) && nft_validate_register_store(ctx, priv->dreg, NULL, @@ -105,7 +108,8 @@ static int nft_hash_dump(struct sk_buff *skb, goto nla_put_failure; if (nla_put_be32(skb, NFTA_HASH_MODULUS, htonl(priv->modulus))) goto nla_put_failure; - if (nla_put_be32(skb, NFTA_HASH_SEED, htonl(priv->seed))) + if (!priv->autogen_seed && + nla_put_be32(skb, NFTA_HASH_SEED, htonl(priv->seed))) goto nla_put_failure; if (priv->offset != 0) if (nla_put_be32(skb, NFTA_HASH_OFFSET, htonl(priv->offset))) -- 2.20.1