netfilter: nf_tables: reject constant set with timeout

This set combination is weird: it allows for elements to be
added/deleted, but once bound to the rule it cannot be updated anymore.
Eventually, all elements expire, leading to an empty set which cannot
be updated anymore. Reject this flags combination.

Cc: stable@vger.kernel.org
Fixes: 761da2935d6e ("netfilter: nf_tables: add set timeout API support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index bd21067f25cfdfdf3e1f3955cb6c58f37f750561..fb07455143a587f245423c0a4680dc08679b6dc6 100644 (file)
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -5004,6 +5004,9 @@ static int nf_tables_newset(struct sk_buff *skb, const struct nfnl_info *info,
                if ((flags & (NFT_SET_ANONYMOUS | NFT_SET_TIMEOUT | NFT_SET_EVAL)) ==
                             (NFT_SET_ANONYMOUS | NFT_SET_TIMEOUT))
                        return -EOPNOTSUPP;
+               if ((flags & (NFT_SET_CONSTANT | NFT_SET_TIMEOUT)) ==
+                            (NFT_SET_CONSTANT | NFT_SET_TIMEOUT))
+                       return -EOPNOTSUPP;
        }
 
        desc.dtype = 0;