netfilter: nft_payload: reject out-of-range attributes via policy

Now that nla_policy allows range checks for bigendian data make use of
this to reject such attributes.  At this time, reject happens later
from the init or select_ops callbacks, but its prone to errors.

In the future, new attributes can be handled via NLA_POLICY_MAX_BE
and exiting ones can be converted one by one.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/netfilter/nft_payload.c b/net/netfilter/nft_payload.c
index eb0e40c..088244f 100644 (file)
--- a/net/netfilter/nft_payload.c
+++ b/net/netfilter/nft_payload.c
@@ -173,10 +173,10 @@ static const struct nla_policy nft_payload_policy[NFTA_PAYLOAD_MAX + 1] = {
        [NFTA_PAYLOAD_SREG]             = { .type = NLA_U32 },
        [NFTA_PAYLOAD_DREG]             = { .type = NLA_U32 },
        [NFTA_PAYLOAD_BASE]             = { .type = NLA_U32 },
-       [NFTA_PAYLOAD_OFFSET]           = { .type = NLA_U32 },
-       [NFTA_PAYLOAD_LEN]              = { .type = NLA_U32 },
+       [NFTA_PAYLOAD_OFFSET]           = NLA_POLICY_MAX_BE(NLA_U32, 255),
+       [NFTA_PAYLOAD_LEN]              = NLA_POLICY_MAX_BE(NLA_U32, 255),
        [NFTA_PAYLOAD_CSUM_TYPE]        = { .type = NLA_U32 },
-       [NFTA_PAYLOAD_CSUM_OFFSET]      = { .type = NLA_U32 },
+       [NFTA_PAYLOAD_CSUM_OFFSET]      = NLA_POLICY_MAX_BE(NLA_U32, 255),
        [NFTA_PAYLOAD_CSUM_FLAGS]       = { .type = NLA_U32 },
 };