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>
diff --git a/net/netfilter/nft_hash.c b/net/netfilter/nft_hash.c
index eb2721a..c4dad12 100644
--- a/net/netfilter/nft_hash.c
+++ b/net/netfilter/nft_hash.c
@@ -21,6 +21,7 @@
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 @@
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 @@
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)))