[PATCH nf-next] netfilter: nf_tables: remove redundant chain validation on register store

[PATCH nf-next] netfilter: nf_tables: remove redundant chain validation on register store

[Pablo Neira Ayuso]

This validation predates the introduction of the state machine that
determines when to enter slow path validation for error reporting.

Currently, table validation is perform when:

- new rule contains expressions that need validation.
- new set element with jump/goto verdict.

Validation on register store skips most checks with no basechains, still
this walks the graph searching for loops and ensuring expressions are
called from the right hook. Remove this.

Fixes: a654de8fdc18 ("netfilter: nf_tables: fix chain dependency validation")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
Supersedes: ("netfilter: nf_tables: skip register jump/goto validation for non-base chain")

No rush to apply this, still running a few more tests here on it.

 net/netfilter/nf_tables_api.c | 11 -----------
 1 file changed, 11 deletions(-)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index f3de2f9bbebf..c46b1bb0efe0 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -11676,21 +11676,10 @@ static int nft_validate_register_store(const struct nft_ctx *ctx,
 				       enum nft_data_types type,
 				       unsigned int len)
 {
-	int err;
-
 	switch (reg) {
 	case NFT_REG_VERDICT:
 		if (type != NFT_DATA_VERDICT)
 			return -EINVAL;
-
-		if (data != NULL &&
-		    (data->verdict.code == NFT_GOTO ||
-		     data->verdict.code == NFT_JUMP)) {
-			err = nft_chain_validate(ctx, data->verdict.chain);
-			if (err < 0)
-				return err;
-		}
-
 		break;
 	default:
 		if (type != NFT_DATA_VALUE)
-- 
2.30.2

Re: [PATCH nf-next] netfilter: nf_tables: remove redundant chain validation on register store

[Florian Westphal]

Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> This validation predates the introduction of the state machine that
> determines when to enter slow path validation for error reporting.
> 
> Currently, table validation is perform when:
> 
> - new rule contains expressions that need validation.
> - new set element with jump/goto verdict.
> 
> Validation on register store skips most checks with no basechains, still
> this walks the graph searching for loops and ensuring expressions are
> called from the right hook. Remove this.
> 
> Fixes: a654de8fdc18 ("netfilter: nf_tables: fix chain dependency validation")
> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
> ---
> Supersedes: ("netfilter: nf_tables: skip register jump/goto validation for non-base chain")
> 
> No rush to apply this, still running a few more tests here on it.

Thanks!  I wonder if this impacts error location reporting.

I agree its not needed from correctness p.o.v. since commit (or abort)
validates entire completed ruleset.