net, neigh: Use NLA_POLICY_MASK helper for NDA_FLAGS_EXT attribute

Instead of open-coding a check for invalid bits in NTF_EXT_MASK, we can just
use the NLA_POLICY_MASK() helper instead, and simplify NDA_FLAGS_EXT sanity
check this way.

Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 4fc601f..922b9ed 100644 (file)
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -1834,7 +1834,7 @@ const struct nla_policy nda_policy[NDA_MAX+1] = {
        [NDA_MASTER]            = { .type = NLA_U32 },
        [NDA_PROTOCOL]          = { .type = NLA_U8 },
        [NDA_NH_ID]             = { .type = NLA_U32 },
-       [NDA_FLAGS_EXT]         = { .type = NLA_U32 },
+       [NDA_FLAGS_EXT]         = NLA_POLICY_MASK(NLA_U32, NTF_EXT_MASK),
        [NDA_FDB_EXT_ATTRS]     = { .type = NLA_NESTED },
 };
 
@@ -1936,10 +1936,6 @@ static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh,
        if (tb[NDA_FLAGS_EXT]) {
                u32 ext = nla_get_u32(tb[NDA_FLAGS_EXT]);
 
-               if (ext & ~NTF_EXT_MASK) {
-                       NL_SET_ERR_MSG(extack, "Invalid extended flags");
-                       goto out;
-               }
                BUILD_BUG_ON(sizeof(neigh->flags) * BITS_PER_BYTE <
                             (sizeof(ndm->ndm_flags) * BITS_PER_BYTE +
                              hweight32(NTF_EXT_MASK)));