netlink: make nla_nest_start() add NLA_F_NESTED flag

Even if the NLA_F_NESTED flag was introduced more than 11 years ago, most
netlink based interfaces (including recently added ones) are still not
setting it in kernel generated messages. Without the flag, message parsers
not aware of attribute semantics (e.g. wireshark dissector or libmnl's
mnl_nlmsg_fprintf()) cannot recognize nested attributes and won't display
the structure of their contents.

Unfortunately we cannot just add the flag everywhere as there may be
userspace applications which check nlattr::nla_type directly rather than
through a helper masking out the flags. Therefore the patch renames
nla_nest_start() to nla_nest_start_noflag() and introduces nla_nest_start()
as a wrapper adding NLA_F_NESTED. The calls which add NLA_F_NESTED manually
are rewritten to use nla_nest_start().

Except for changes in include/net/netlink.h, the patch was generated using
this semantic patch:

@@ expression E1, E2; @@
-nla_nest_start(E1, E2)
+nla_nest_start_noflag(E1, E2)

@@ expression E1, E2; @@
-nla_nest_start_noflag(E1, E2 | NLA_F_NESTED)
+nla_nest_start(E1, E2)

Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 15 insertions, 14 deletions

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 9d888dc6be38..2b79c250ecb4 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -1200,7 +1200,7 @@ static int nft_dump_stats(struct sk_buff *skb, struct nft_stats __percpu *stats)
 		total.pkts += pkts;
 		total.bytes += bytes;
 	}
-	nest = nla_nest_start(skb, NFTA_CHAIN_COUNTERS);
+	nest = nla_nest_start_noflag(skb, NFTA_CHAIN_COUNTERS);
 	if (nest == NULL)
 		goto nla_put_failure;
 
@@ -1248,7 +1248,7 @@ static int nf_tables_fill_chain_info(struct sk_buff *skb, struct net *net,
 		const struct nf_hook_ops *ops = &basechain->ops;
 		struct nlattr *nest;
 
-		nest = nla_nest_start(skb, NFTA_CHAIN_HOOK);
+		nest = nla_nest_start_noflag(skb, NFTA_CHAIN_HOOK);
 		if (nest == NULL)
 			goto nla_put_failure;
 		if (nla_put_be32(skb, NFTA_HOOK_HOOKNUM, htonl(ops->hooknum)))
@@ -2059,7 +2059,8 @@ static int nf_tables_fill_expr_info(struct sk_buff *skb,
 		goto nla_put_failure;
 
 	if (expr->ops->dump) {
-		struct nlattr *data = nla_nest_start(skb, NFTA_EXPR_DATA);
+		struct nlattr *data = nla_nest_start_noflag(skb,
+							    NFTA_EXPR_DATA);
 		if (data == NULL)
 			goto nla_put_failure;
 		if (expr->ops->dump(skb, expr) < 0)
@@ -2078,7 +2079,7 @@ int nft_expr_dump(struct sk_buff *skb, unsigned int attr,
 {
 	struct nlattr *nest;
 
-	nest = nla_nest_start(skb, attr);
+	nest = nla_nest_start_noflag(skb, attr);
 	if (!nest)
 		goto nla_put_failure;
 	if (nf_tables_fill_expr_info(skb, expr) < 0)
@@ -2289,7 +2290,7 @@ static int nf_tables_fill_rule_info(struct sk_buff *skb, struct net *net,
 			goto nla_put_failure;
 	}
 
-	list = nla_nest_start(skb, NFTA_RULE_EXPRESSIONS);
+	list = nla_nest_start_noflag(skb, NFTA_RULE_EXPRESSIONS);
 	if (list == NULL)
 		goto nla_put_failure;
 	nft_rule_for_each_expr(expr, next, rule) {
@@ -3258,7 +3259,7 @@ static int nf_tables_fill_set(struct sk_buff *skb, const struct nft_ctx *ctx,
 	if (nla_put(skb, NFTA_SET_USERDATA, set->udlen, set->udata))
 		goto nla_put_failure;
 
-	desc = nla_nest_start(skb, NFTA_SET_DESC);
+	desc = nla_nest_start_noflag(skb, NFTA_SET_DESC);
 	if (desc == NULL)
 		goto nla_put_failure;
 	if (set->size &&
@@ -3908,7 +3909,7 @@ static int nf_tables_fill_setelem(struct sk_buff *skb,
 	unsigned char *b = skb_tail_pointer(skb);
 	struct nlattr *nest;
 
-	nest = nla_nest_start(skb, NFTA_LIST_ELEM);
+	nest = nla_nest_start_noflag(skb, NFTA_LIST_ELEM);
 	if (nest == NULL)
 		goto nla_put_failure;
 
@@ -4052,7 +4053,7 @@ static int nf_tables_dump_set(struct sk_buff *skb, struct netlink_callback *cb)
 	if (nla_put_string(skb, NFTA_SET_ELEM_LIST_SET, set->name))
 		goto nla_put_failure;
 
-	nest = nla_nest_start(skb, NFTA_SET_ELEM_LIST_ELEMENTS);
+	nest = nla_nest_start_noflag(skb, NFTA_SET_ELEM_LIST_ELEMENTS);
 	if (nest == NULL)
 		goto nla_put_failure;
 
@@ -4124,7 +4125,7 @@ static int nf_tables_fill_setelem_info(struct sk_buff *skb,
 	if (nla_put_string(skb, NFTA_SET_NAME, set->name))
 		goto nla_put_failure;
 
-	nest = nla_nest_start(skb, NFTA_SET_ELEM_LIST_ELEMENTS);
+	nest = nla_nest_start_noflag(skb, NFTA_SET_ELEM_LIST_ELEMENTS);
 	if (nest == NULL)
 		goto nla_put_failure;
 
@@ -5014,7 +5015,7 @@ static int nft_object_dump(struct sk_buff *skb, unsigned int attr,
 {
 	struct nlattr *nest;
 
-	nest = nla_nest_start(skb, attr);
+	nest = nla_nest_start_noflag(skb, attr);
 	if (!nest)
 		goto nla_put_failure;
 	if (obj->ops->dump(skb, obj, reset) < 0)
@@ -5831,14 +5832,14 @@ static int nf_tables_fill_flowtable_info(struct sk_buff *skb, struct net *net,
 			 NFTA_FLOWTABLE_PAD))
 		goto nla_put_failure;
 
-	nest = nla_nest_start(skb, NFTA_FLOWTABLE_HOOK);
+	nest = nla_nest_start_noflag(skb, NFTA_FLOWTABLE_HOOK);
 	if (!nest)
 		goto nla_put_failure;
 	if (nla_put_be32(skb, NFTA_FLOWTABLE_HOOK_NUM, htonl(flowtable->hooknum)) ||
 	    nla_put_be32(skb, NFTA_FLOWTABLE_HOOK_PRIORITY, htonl(flowtable->priority)))
 		goto nla_put_failure;
 
-	nest_devs = nla_nest_start(skb, NFTA_FLOWTABLE_HOOK_DEVS);
+	nest_devs = nla_nest_start_noflag(skb, NFTA_FLOWTABLE_HOOK_DEVS);
 	if (!nest_devs)
 		goto nla_put_failure;
 
@@ -7264,7 +7265,7 @@ int nft_verdict_dump(struct sk_buff *skb, int type, const struct nft_verdict *v)
 {
 	struct nlattr *nest;
 
-	nest = nla_nest_start(skb, type);
+	nest = nla_nest_start_noflag(skb, type);
 	if (!nest)
 		goto nla_put_failure;
 
@@ -7377,7 +7378,7 @@ int nft_data_dump(struct sk_buff *skb, int attr, const struct nft_data *data,
 	struct nlattr *nest;
 	int err;
 
-	nest = nla_nest_start(skb, attr);
+	nest = nla_nest_start_noflag(skb, attr);
 	if (nest == NULL)
 		return -1;