netfilter: nfnetlink_acct: validate NFACCT_QUOTA parameter

If a quota bit is set in NFACCT_FLAGS but the NFACCT_QUOTA parameter is
missing then a NULL pointer dereference is triggered. CAP_NET_ADMIN is
required to trigger the bug.
Signed-off-by: NPhil Turnbull <phil.turnbull@oracle.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nfnetlink_acct.c

@@ -96,6 +96,8 @@ static int nfnl_acct_new(struct net *net, struct sock *nfnl,
 			return -EINVAL;
 		if (flags & NFACCT_F_OVERQUOTA)
 			return -EINVAL;
+		if ((flags & NFACCT_F_QUOTA) && !tb[NFACCT_QUOTA])
+			return -EINVAL;
 
 		size += sizeof(u64);
 	}