[PATCH nft] evaluate: bogus error when adding devices to flowtable

[PATCH nft] evaluate: bogus error when adding devices to flowtable

[Pablo Neira Ayuso]

Bail out if flowtable declaration is missing and no devices are
specified.

Otherwise, this reports a bogus error when adding new devices to an
existing flowtable.

 # nft -v
 nftables v1.0.9 (Old Doc Yak #3)
 # ip link add dummy1 type dummy
 # ip link set dummy1 up
 # nft 'create flowtable inet filter f1 { hook ingress priority 0; counter }'
 # nft 'add flowtable inet filter f1 { devices = { dummy1 } ; }'
 Error: missing hook and priority in flowtable declaration
 add flowtable inet filter f1 { devices = { dummy1 } ; }
                           ^^^^^^^^^^^^^^^^^^^^^^^^

Fixes: 5ad475fce5a1 ("evaluate: bail out if new flowtable does not specify hook and priority")
Reported-by: Martin Gignac <martin.gignac@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 src/evaluate.c                                | 2 +-
 tests/shell/testcases/flowtable/0015destroy_0 | 8 ++++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/evaluate.c b/src/evaluate.c
index 13b6a603de22..bcf83d804f32 100644
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -4867,7 +4867,7 @@ static int flowtable_evaluate(struct eval_ctx *ctx, struct flowtable *ft)
 		return table_not_found(ctx);
 
 	if (!ft_cache_find(table, ft->handle.flowtable.name)) {
-		if (!ft->hook.name)
+		if (!ft->hook.name && !ft->dev_expr)
 			return chain_error(ctx, ft, "missing hook and priority in flowtable declaration");
 
 		ft_cache_add(flowtable_get(ft), table);
diff --git a/tests/shell/testcases/flowtable/0015destroy_0 b/tests/shell/testcases/flowtable/0015destroy_0
index d2a87da080fb..cea33524831f 100755
--- a/tests/shell/testcases/flowtable/0015destroy_0
+++ b/tests/shell/testcases/flowtable/0015destroy_0
@@ -2,6 +2,11 @@
 
 # NFT_TEST_REQUIRES(NFT_TEST_HAVE_destroy)
 
+trap "ip link del dummy1" EXIT
+
+ip link add dummy1 type dummy
+ip link set dummy1 up
+
 $NFT add table t
 
 # pass for non-existent flowtable
@@ -9,4 +14,7 @@ $NFT destroy flowtable t f
 
 # successfully delete existing flowtable
 $NFT add flowtable t f '{ hook ingress priority 10; devices = { lo }; }'
+
+$NFT 'add flowtable t f { devices = { dummy1 } ; }'
+
 $NFT destroy flowtable t f
-- 
2.30.2