netfilter: nf_tables: disallow anonymous set with timeout flag

jira VULN-827
cve CVE-2024-26642
commit-author Pablo Neira Ayuso <[email protected]>
commit 1660360

Anonymous sets are never used with timeout from userspace, reject this.
Exception to this rule is NFT_SET_EVAL to ensure legacy meters still work.

	Cc: [email protected]
Fixes: 761da29 ("netfilter: nf_tables: add set timeout API support")
	Reported-by: lonial con <[email protected]>
	Signed-off-by: Pablo Neira Ayuso <[email protected]>
(cherry picked from commit 1660360)
	Signed-off-by: Greg Rose <[email protected]>

Author: gvrose8192

net/netfilter/nf_tables_api.c

@@ -4152,6 +4152,9 @@ static int nf_tables_newset(struct net *net, struct sock *nlsk,
 		if ((flags & (NFT_SET_EVAL | NFT_SET_OBJECT)) ==
 			     (NFT_SET_EVAL | NFT_SET_OBJECT))
 			return -EOPNOTSUPP;
+		if ((flags & (NFT_SET_ANONYMOUS | NFT_SET_TIMEOUT | NFT_SET_EVAL)) ==
+			     (NFT_SET_ANONYMOUS | NFT_SET_TIMEOUT))
+			return -EOPNOTSUPP;
 	}
 
 	dtype = 0;