rtnetlink: ifla_vf_policy: fix misuses of NLA_BINARY

commit 364d5716 upstream.

ifla_vf_policy[] is wrong in advertising its individual member types as
NLA_BINARY since .type = NLA_BINARY in combination with .len declares the
len member as *max* attribute length [0, len].

The issue is that when do_setvfinfo() is being called to set up a VF
through ndo handler, we could set corrupted data if the attribute length
is less than the size of the related structure itself.

The intent is exactly the opposite, namely to make sure to pass at least
data of minimum size of len.

Fixes: ebc08a6f ("rtnetlink: Add VF config code to rtnetlink")
Cc: Mitch Williams <mitch.a.williams@intel.com>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

net/core/rtnetlink.c

@@ -1207,18 +1207,12 @@ static const struct nla_policy ifla_vfinfo_policy[IFLA_VF_INFO_MAX+1] = {
 };
 
 static const struct nla_policy ifla_vf_policy[IFLA_VF_MAX+1] = {
-	[IFLA_VF_MAC]		= { .type = NLA_BINARY,
-				    .len = sizeof(struct ifla_vf_mac) },
-	[IFLA_VF_VLAN]		= { .type = NLA_BINARY,
-				    .len = sizeof(struct ifla_vf_vlan) },
-	[IFLA_VF_TX_RATE]	= { .type = NLA_BINARY,
-				    .len = sizeof(struct ifla_vf_tx_rate) },
-	[IFLA_VF_SPOOFCHK]	= { .type = NLA_BINARY,
-				    .len = sizeof(struct ifla_vf_spoofchk) },
-	[IFLA_VF_RATE]		= { .type = NLA_BINARY,
-				    .len = sizeof(struct ifla_vf_rate) },
-	[IFLA_VF_LINK_STATE]	= { .type = NLA_BINARY,
-				    .len = sizeof(struct ifla_vf_link_state) },
+	[IFLA_VF_MAC]		= { .len = sizeof(struct ifla_vf_mac) },
+	[IFLA_VF_VLAN]		= { .len = sizeof(struct ifla_vf_vlan) },
+	[IFLA_VF_TX_RATE]	= { .len = sizeof(struct ifla_vf_tx_rate) },
+	[IFLA_VF_SPOOFCHK]	= { .len = sizeof(struct ifla_vf_spoofchk) },
+	[IFLA_VF_RATE]		= { .len = sizeof(struct ifla_vf_rate) },
+	[IFLA_VF_LINK_STATE]	= { .len = sizeof(struct ifla_vf_link_state) },
 };
 
 static const struct nla_policy ifla_port_policy[IFLA_PORT_MAX+1] = {