From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: Wed, 19 May 2021 13:32:20 +0200
Subject: netfilter: nf_tables: missing error reporting for not selected
 expressions
Patch-mainline: v5.13-rc5
Git-commit: c781471d67a56d7d4c113669a11ede0463b5c719
References: bsc#1176447

Sometimes users forget to turn on nftables extensions from Kconfig that
they need. In such case, the error reporting from userspace is
misleading:

 $ sudo nft add rule x y counter
 Error: Could not process rule: No such file or directory
 add rule x y counter
 ^^^^^^^^^^^^^^^^^^^^

Add missing NL_SET_BAD_ATTR() to provide a hint:

 $ nft add rule x y counter
 Error: Could not process rule: No such file or directory
 add rule x y counter
              ^^^^^^^

Fixes: 83d9dcba06c5 ("netfilter: nf_tables: extended netlink error reporting for expressions")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 net/netfilter/nf_tables_api.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -3205,8 +3205,10 @@ static int nf_tables_newrule(struct net
 			if (n == NFT_RULE_MAXEXPRS)
 				goto err1;
 			err = nf_tables_expr_parse(&ctx, tmp, &info[n]);
-			if (err < 0)
+			if (err < 0) {
+				NL_SET_BAD_ATTR(extack, tmp);
 				goto err1;
+			}
 			size += info[n].ops->size;
 			n++;
 		}