| From 687fa64cea6afbbe5856f08ddcc7242be2262d1f Mon Sep 17 00:00:00 2001 |
| From: Florian Westphal <fw@strlen.de> |
| Date: Thu, 19 Sep 2019 16:56:44 +0200 |
| Subject: [PATCH] netfilter: nf_tables: allow lookups in dynamic sets |
| |
| commit acab713177377d9e0889c46bac7ff0cfb9a90c4d upstream. |
| |
| This un-breaks lookups in sets that have the 'dynamic' flag set. |
| Given this active example configuration: |
| |
| table filter { |
| set set1 { |
| type ipv4_addr |
| size 64 |
| flags dynamic,timeout |
| timeout 1m |
| } |
| |
| chain input { |
| type filter hook input priority 0; policy accept; |
| } |
| } |
| |
| ... this works: |
| nft add rule ip filter input add @set1 { ip saddr } |
| |
| -> whenever rule is triggered, the source ip address is inserted |
| into the set (if it did not exist). |
| |
| This won't work: |
| nft add rule ip filter input ip saddr @set1 counter |
| Error: Could not process rule: Operation not supported |
| |
| In other words, we can add entries to the set, but then can't make |
| matching decision based on that set. |
| |
| That is just wrong -- all set backends support lookups (else they would |
| not be very useful). |
| The failure comes from an explicit rejection in nft_lookup.c. |
| |
| Looking at the history, it seems like NFT_SET_EVAL used to mean |
| 'set contains expressions' (aka. "is a meter"), for instance something like |
| |
| nft add rule ip filter input meter example { ip saddr limit rate 10/second } |
| or |
| nft add rule ip filter input meter example { ip saddr counter } |
| |
| The actual meaning of NFT_SET_EVAL however, is |
| 'set can be updated from the packet path'. |
| |
| 'meters' and packet-path insertions into sets, such as |
| 'add @set { ip saddr }' use exactly the same kernel code (nft_dynset.c) |
| and thus require a set backend that provides the ->update() function. |
| |
| The only set that provides this also is the only one that has the |
| NFT_SET_EVAL feature flag. |
| |
| Removing the wrong check makes the above example work. |
| While at it, also fix the flag check during set instantiation to |
| allow supported combinations only. |
| |
| Fixes: 8aeff920dcc9b3f ("netfilter: nf_tables: add stateful object reference to set elements") |
| Signed-off-by: Florian Westphal <fw@strlen.de> |
| Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c |
| index 8e4cdae2c4f1..4d8714d78192 100644 |
| --- a/net/netfilter/nf_tables_api.c |
| +++ b/net/netfilter/nf_tables_api.c |
| @@ -3521,8 +3521,11 @@ static int nf_tables_newset(struct net *net, struct sock *nlsk, |
| NFT_SET_OBJECT)) |
| return -EINVAL; |
| /* Only one of these operations is supported */ |
| - if ((flags & (NFT_SET_MAP | NFT_SET_EVAL | NFT_SET_OBJECT)) == |
| - (NFT_SET_MAP | NFT_SET_EVAL | NFT_SET_OBJECT)) |
| + if ((flags & (NFT_SET_MAP | NFT_SET_OBJECT)) == |
| + (NFT_SET_MAP | NFT_SET_OBJECT)) |
| + return -EOPNOTSUPP; |
| + if ((flags & (NFT_SET_EVAL | NFT_SET_OBJECT)) == |
| + (NFT_SET_EVAL | NFT_SET_OBJECT)) |
| return -EOPNOTSUPP; |
| } |
| |
| diff --git a/net/netfilter/nft_lookup.c b/net/netfilter/nft_lookup.c |
| index c0560bf3c31b..660bad688e2b 100644 |
| --- a/net/netfilter/nft_lookup.c |
| +++ b/net/netfilter/nft_lookup.c |
| @@ -73,9 +73,6 @@ static int nft_lookup_init(const struct nft_ctx *ctx, |
| if (IS_ERR(set)) |
| return PTR_ERR(set); |
| |
| - if (set->flags & NFT_SET_EVAL) |
| - return -EOPNOTSUPP; |
| - |
| priv->sreg = nft_parse_register(tb[NFTA_LOOKUP_SREG]); |
| err = nft_validate_register_load(priv->sreg, set->klen); |
| if (err < 0) |
| -- |
| 2.7.4 |
| |