On Mon, Sep 08, 2025 at 12:29:03PM +0200, Pablo Neira Ayuso wrote:
> On Fri, Aug 29, 2025 at 04:25:11PM +0200, Phil Sutter wrote:
> > Complete commit a66b5ad9540dd ("src: allow for updating devices on
> > existing netdev chain") in supporting inet family ingress hook chains as
> > well. The kernel does already but nft has to add a proper hooknum
> > attribute to pass the checks.
> >
> > The hook.num field has to be initialized from hook.name using
> > str2hooknum(), which is part of chain evaluation. Calling
> > chain_evaluate() just for that purpose is a bit over the top, but the
> > hook name lookup may fail and performing chain evaluation for delete
> > command as well fits more into the code layout than duplicating parts of
> > it in mnl_nft_chain_del() or elsewhere. Just avoid the
> > chain_cache_find() call as its assert() triggers when deleting by
> > handle and also don't add to be deleted chains to cache.
> >
> > Signed-off-by: Phil Sutter <phil@xxxxxx>
> > ---
> > src/evaluate.c | 6 ++++--
> > src/mnl.c | 2 ++
> > 2 files changed, 6 insertions(+), 2 deletions(-)
> >
> > diff --git a/src/evaluate.c b/src/evaluate.c
> > index b7e4f71fdfbc9..db4ac18f1dc9f 100644
> > --- a/src/evaluate.c
> > +++ b/src/evaluate.c
> > @@ -5758,7 +5758,9 @@ static int chain_evaluate(struct eval_ctx *ctx, struct chain *chain)
> > return table_not_found(ctx);
> >
> > if (chain == NULL) {
> > - if (!chain_cache_find(table, ctx->cmd->handle.chain.name)) {
> > + if (ctx->cmd->op != CMD_DELETE &&
> > + ctx->cmd->op != CMD_DESTROY &&
> > + !chain_cache_find(table, ctx->cmd->handle.chain.name)) {
> > chain = chain_alloc();
> > handle_merge(&chain->handle, &ctx->cmd->handle);
> > chain_cache_add(chain, table);
> > @@ -6070,7 +6072,7 @@ static int cmd_evaluate_delete(struct eval_ctx *ctx, struct cmd *cmd)
> > return 0;
> > case CMD_OBJ_CHAIN:
> > chain_del_cache(ctx, cmd);
> > - return 0;
> > + return chain_evaluate(ctx, cmd->chain);
>
> Maybe fix this to perform chain_del_cache() after chain_evaluate()?
> ie.
>
> if (chain_evaluate(ctx, cmd->chain) < 0)
> return -1;
>
> chain_del_cache(ctx, cmd);
My suggestion won't work.
Maybe add a specific chain_del_evaluate(), see untested patch attached.
diff --git a/src/evaluate.c b/src/evaluate.c
index d4971228b61f..7c72a453d0f3 100644
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -5722,6 +5722,37 @@ static uint32_t str2hooknum(uint32_t family, const char *hook)
return NF_INET_NUMHOOKS;
}
+static int chain_del_evaluate(struct eval_ctx *ctx, struct chain *chain)
+{
+ struct table *table;
+
+ table = table_cache_find(&ctx->nft->cache.table_cache,
+ ctx->cmd->handle.table.name,
+ ctx->cmd->handle.family);
+ if (table == NULL)
+ return table_not_found(ctx);
+
+ if (chain->dev_expr) {
+ if (!(chain->flags & CHAIN_F_BASECHAIN))
+ chain->flags |= CHAIN_F_BASECHAIN;
+
+ if (chain->handle.family == NFPROTO_NETDEV ||
+ (chain->handle.family == NFPROTO_INET &&
+ chain->hook.num == NF_INET_INGRESS)) {
+ if (chain->dev_expr &&
+ !evaluate_device_expr(ctx, &chain->dev_expr))
+ return -1;
+ } else if (chain->dev_expr) {
+ return __stmt_binary_error(ctx, &chain->dev_expr->location, NULL,
+ "This chain type cannot be bound to device");
+ }
+ }
+
+ chain_del_cache(ctx, cmd);
+
+ return 0;
+}
+
static int chain_evaluate(struct eval_ctx *ctx, struct chain *chain)
{
struct table *table;
