* [PATCH nf] netfilter: nf_tables: allow lookups in dynamic sets
@ 2019-09-19 14:56 Florian Westphal
2019-09-20 8:22 ` Pablo Neira Ayuso
0 siblings, 1 reply; 2+ messages in thread
From: Florian Westphal @ 2019-09-19 14:56 UTC (permalink / raw)
To: netfilter-devel; +Cc: Florian Westphal
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>
---
net/netfilter/nf_tables_api.c | 7 +++++--
net/netfilter/nft_lookup.c | 3 ---
2 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index e4a68dc42694..bbaa8bac2c2d 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -3562,8 +3562,11 @@ 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)
--
2.21.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH nf] netfilter: nf_tables: allow lookups in dynamic sets
2019-09-19 14:56 [PATCH nf] netfilter: nf_tables: allow lookups in dynamic sets Florian Westphal
@ 2019-09-20 8:22 ` Pablo Neira Ayuso
0 siblings, 0 replies; 2+ messages in thread
From: Pablo Neira Ayuso @ 2019-09-20 8:22 UTC (permalink / raw)
To: Florian Westphal; +Cc: netfilter-devel
On Thu, Sep 19, 2019 at 04:56:44PM +0200, Florian Westphal wrote:
> This un-breaks lookups in sets that have the 'dynamic' flag set.
Applied, thanks.
^ permalink raw reply [flat|nested] 2+ messages in thread
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