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, 25 insertions, 23 deletions

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 5fa5bf3e9945..8ad44b299e72 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -634,7 +634,7 @@ static int rtnl_link_slave_info_fill(struct sk_buff *skb,
 	if (nla_put_string(skb, IFLA_INFO_SLAVE_KIND, ops->kind) < 0)
 		return -EMSGSIZE;
 	if (ops->fill_slave_info) {
-		slave_data = nla_nest_start(skb, IFLA_INFO_SLAVE_DATA);
+		slave_data = nla_nest_start_noflag(skb, IFLA_INFO_SLAVE_DATA);
 		if (!slave_data)
 			return -EMSGSIZE;
 		err = ops->fill_slave_info(skb, master_dev, dev);
@@ -666,7 +666,7 @@ static int rtnl_link_info_fill(struct sk_buff *skb,
 			return err;
 	}
 	if (ops->fill_info) {
-		data = nla_nest_start(skb, IFLA_INFO_DATA);
+		data = nla_nest_start_noflag(skb, IFLA_INFO_DATA);
 		if (data == NULL)
 			return -EMSGSIZE;
 		err = ops->fill_info(skb, dev);
@@ -686,7 +686,7 @@ static int rtnl_link_fill(struct sk_buff *skb, const struct net_device *dev)
 	struct nlattr *linkinfo;
 	int err = -EMSGSIZE;
 
-	linkinfo = nla_nest_start(skb, IFLA_LINKINFO);
+	linkinfo = nla_nest_start_noflag(skb, IFLA_LINKINFO);
 	if (linkinfo == NULL)
 		goto out;
 
@@ -755,7 +755,7 @@ int rtnetlink_put_metrics(struct sk_buff *skb, u32 *metrics)
 	struct nlattr *mx;
 	int i, valid = 0;
 
-	mx = nla_nest_start(skb, RTA_METRICS);
+	mx = nla_nest_start_noflag(skb, RTA_METRICS);
 	if (mx == NULL)
 		return -ENOBUFS;
 
@@ -1036,12 +1036,12 @@ static int rtnl_vf_ports_fill(struct sk_buff *skb, struct net_device *dev)
 	int vf;
 	int err;
 
-	vf_ports = nla_nest_start(skb, IFLA_VF_PORTS);
+	vf_ports = nla_nest_start_noflag(skb, IFLA_VF_PORTS);
 	if (!vf_ports)
 		return -EMSGSIZE;
 
 	for (vf = 0; vf < dev_num_vf(dev->dev.parent); vf++) {
-		vf_port = nla_nest_start(skb, IFLA_VF_PORT);
+		vf_port = nla_nest_start_noflag(skb, IFLA_VF_PORT);
 		if (!vf_port)
 			goto nla_put_failure;
 		if (nla_put_u32(skb, IFLA_PORT_VF, vf))
@@ -1070,7 +1070,7 @@ static int rtnl_port_self_fill(struct sk_buff *skb, struct net_device *dev)
 	struct nlattr *port_self;
 	int err;
 
-	port_self = nla_nest_start(skb, IFLA_PORT_SELF);
+	port_self = nla_nest_start_noflag(skb, IFLA_PORT_SELF);
 	if (!port_self)
 		return -EMSGSIZE;
 
@@ -1247,7 +1247,7 @@ static noinline_for_stack int rtnl_fill_vfinfo(struct sk_buff *skb,
 	vf_linkstate.link_state = ivi.linkstate;
 	vf_rss_query_en.setting = ivi.rss_query_en;
 	vf_trust.setting = ivi.trusted;
-	vf = nla_nest_start(skb, IFLA_VF_INFO);
+	vf = nla_nest_start_noflag(skb, IFLA_VF_INFO);
 	if (!vf)
 		goto nla_put_vfinfo_failure;
 	if (nla_put(skb, IFLA_VF_MAC, sizeof(vf_mac), &vf_mac) ||
@@ -1266,7 +1266,7 @@ static noinline_for_stack int rtnl_fill_vfinfo(struct sk_buff *skb,
 	    nla_put(skb, IFLA_VF_TRUST,
 		    sizeof(vf_trust), &vf_trust))
 		goto nla_put_vf_failure;
-	vfvlanlist = nla_nest_start(skb, IFLA_VF_VLAN_LIST);
+	vfvlanlist = nla_nest_start_noflag(skb, IFLA_VF_VLAN_LIST);
 	if (!vfvlanlist)
 		goto nla_put_vf_failure;
 	if (nla_put(skb, IFLA_VF_VLAN_INFO, sizeof(vf_vlan_info),
@@ -1279,7 +1279,7 @@ static noinline_for_stack int rtnl_fill_vfinfo(struct sk_buff *skb,
 	if (dev->netdev_ops->ndo_get_vf_stats)
 		dev->netdev_ops->ndo_get_vf_stats(dev, vfs_num,
 						&vf_stats);
-	vfstats = nla_nest_start(skb, IFLA_VF_STATS);
+	vfstats = nla_nest_start_noflag(skb, IFLA_VF_STATS);
 	if (!vfstats)
 		goto nla_put_vf_failure;
 	if (nla_put_u64_64bit(skb, IFLA_VF_STATS_RX_PACKETS,
@@ -1329,7 +1329,7 @@ static noinline_for_stack int rtnl_fill_vf(struct sk_buff *skb,
 	if (!dev->netdev_ops->ndo_get_vf_config)
 		return 0;
 
-	vfinfo = nla_nest_start(skb, IFLA_VFINFO_LIST);
+	vfinfo = nla_nest_start_noflag(skb, IFLA_VFINFO_LIST);
 	if (!vfinfo)
 		return -EMSGSIZE;
 
@@ -1414,7 +1414,7 @@ static int rtnl_xdp_fill(struct sk_buff *skb, struct net_device *dev)
 	int err;
 	u8 mode;
 
-	xdp = nla_nest_start(skb, IFLA_XDP);
+	xdp = nla_nest_start_noflag(skb, IFLA_XDP);
 	if (!xdp)
 		return -EMSGSIZE;
 
@@ -1541,7 +1541,7 @@ static int rtnl_fill_link_af(struct sk_buff *skb,
 	const struct rtnl_af_ops *af_ops;
 	struct nlattr *af_spec;
 
-	af_spec = nla_nest_start(skb, IFLA_AF_SPEC);
+	af_spec = nla_nest_start_noflag(skb, IFLA_AF_SPEC);
 	if (!af_spec)
 		return -EMSGSIZE;
 
@@ -1552,7 +1552,7 @@ static int rtnl_fill_link_af(struct sk_buff *skb,
 		if (!af_ops->fill_link_af)
 			continue;
 
-		af = nla_nest_start(skb, af_ops->family);
+		af = nla_nest_start_noflag(skb, af_ops->family);
 		if (!af)
 			return -EMSGSIZE;
 
@@ -4273,7 +4273,7 @@ int ndo_dflt_bridge_getlink(struct sk_buff *skb, u32 pid, u32 seq,
 	     nla_put_u32(skb, IFLA_LINK, dev_get_iflink(dev))))
 		goto nla_put_failure;
 
-	br_afspec = nla_nest_start(skb, IFLA_AF_SPEC);
+	br_afspec = nla_nest_start_noflag(skb, IFLA_AF_SPEC);
 	if (!br_afspec)
 		goto nla_put_failure;
 
@@ -4297,7 +4297,7 @@ int ndo_dflt_bridge_getlink(struct sk_buff *skb, u32 pid, u32 seq,
 	}
 	nla_nest_end(skb, br_afspec);
 
-	protinfo = nla_nest_start(skb, IFLA_PROTINFO | NLA_F_NESTED);
+	protinfo = nla_nest_start(skb, IFLA_PROTINFO);
 	if (!protinfo)
 		goto nla_put_failure;
 
@@ -4776,8 +4776,8 @@ static int rtnl_fill_statsinfo(struct sk_buff *skb, struct net_device *dev,
 
 		if (ops && ops->fill_linkxstats) {
 			*idxattr = IFLA_STATS_LINK_XSTATS;
-			attr = nla_nest_start(skb,
-					      IFLA_STATS_LINK_XSTATS);
+			attr = nla_nest_start_noflag(skb,
+						     IFLA_STATS_LINK_XSTATS);
 			if (!attr)
 				goto nla_put_failure;
 
@@ -4799,8 +4799,8 @@ static int rtnl_fill_statsinfo(struct sk_buff *skb, struct net_device *dev,
 			ops = master->rtnl_link_ops;
 		if (ops && ops->fill_linkxstats) {
 			*idxattr = IFLA_STATS_LINK_XSTATS_SLAVE;
-			attr = nla_nest_start(skb,
-					      IFLA_STATS_LINK_XSTATS_SLAVE);
+			attr = nla_nest_start_noflag(skb,
+						     IFLA_STATS_LINK_XSTATS_SLAVE);
 			if (!attr)
 				goto nla_put_failure;
 
@@ -4815,7 +4815,8 @@ static int rtnl_fill_statsinfo(struct sk_buff *skb, struct net_device *dev,
 	if (stats_attr_valid(filter_mask, IFLA_STATS_LINK_OFFLOAD_XSTATS,
 			     *idxattr)) {
 		*idxattr = IFLA_STATS_LINK_OFFLOAD_XSTATS;
-		attr = nla_nest_start(skb, IFLA_STATS_LINK_OFFLOAD_XSTATS);
+		attr = nla_nest_start_noflag(skb,
+					     IFLA_STATS_LINK_OFFLOAD_XSTATS);
 		if (!attr)
 			goto nla_put_failure;
 
@@ -4834,7 +4835,7 @@ static int rtnl_fill_statsinfo(struct sk_buff *skb, struct net_device *dev,
 		struct rtnl_af_ops *af_ops;
 
 		*idxattr = IFLA_STATS_AF_SPEC;
-		attr = nla_nest_start(skb, IFLA_STATS_AF_SPEC);
+		attr = nla_nest_start_noflag(skb, IFLA_STATS_AF_SPEC);
 		if (!attr)
 			goto nla_put_failure;
 
@@ -4844,7 +4845,8 @@ static int rtnl_fill_statsinfo(struct sk_buff *skb, struct net_device *dev,
 				struct nlattr *af;
 				int err;
 
-				af = nla_nest_start(skb, af_ops->family);
+				af = nla_nest_start_noflag(skb,
+							   af_ops->family);
 				if (!af) {
 					rcu_read_unlock();
 					goto nla_put_failure;