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authorLiping Zhang <zlpnobody@gmail.com>2017-04-03 16:34:38 +0800
committerPablo Neira Ayuso <pablo@netfilter.org>2017-04-13 23:20:13 +0200
commit79e09ef96b6a5fb888f5241f3aa707e9ad0b1cce (patch)
treee71a4bd57d30a74c541e24983db101c3b9dd2403 /net
parent7cddd967bfc2e4fc6b3218c2ddc67fbeed433ad3 (diff)
downloadlinux-79e09ef96b6a5fb888f5241f3aa707e9ad0b1cce.tar.gz
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 <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
-rw-r--r--net/netfilter/nft_hash.c10
1 files 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)))