macvlan: validate flags

commit df8ef8f3aaa6692970a436204c4429210addb23a
    macvlan: add FDB bridge ops and macvlan flags
added a flags field to macvlan, which can be
controlled from userspace.
The idea is to make the interface future-proof
so we can add flags and not new fields.

However, flags value isn't validated, as a result,
userspace can't detect which flags are supported.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index d0f9c2f..16b43bf 100644 (file)
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -739,6 +739,10 @@ static int macvlan_validate(struct nlattr *tb[], struct nlattr *data[])
                        return -EADDRNOTAVAIL;
        }
 
+       if (data && data[IFLA_MACVLAN_FLAGS] &&
+           nla_get_u16(data[IFLA_MACVLAN_FLAGS]) & ~MACVLAN_FLAG_NOPROMISC)
+               return -EINVAL;
+
        if (data && data[IFLA_MACVLAN_MODE]) {
                switch (nla_get_u32(data[IFLA_MACVLAN_MODE])) {
                case MACVLAN_MODE_PRIVATE: