netfilter: ipset: Introduce new operation to get both setname and family

ip[6]tables set match and SET target need to know the family of the set
in order to reject adding rules which refer to a set with a non-mathcing
family. Currently such rules are silently accepted and then ignored
instead of generating a clear error message to the user, which is not
helpful.

Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>

2 files changed, 25 insertions, 0 deletions

diff --git a/include/uapi/linux/netfilter/ipset/ip_set.h b/include/uapi/linux/netfilter/ipset/ip_set.h
index 8024cdf13b70..2b61ac44dcc1 100644
--- a/include/uapi/linux/netfilter/ipset/ip_set.h
+++ b/include/uapi/linux/netfilter/ipset/ip_set.h
@@ -250,6 +250,14 @@ struct ip_set_req_get_set {
 #define IP_SET_OP_GET_BYINDEX   0x00000007      /* Get set name by index */
 /* Uses ip_set_req_get_set */
 
+#define IP_SET_OP_GET_FNAME     0x00000008      /* Get set index and family */
+struct ip_set_req_get_set_family {
+        unsigned int op;
+        unsigned int version;
+        unsigned int family;
+        union ip_set_name_index set;
+};
+
 #define IP_SET_OP_VERSION       0x00000100      /* Ask kernel version */
 struct ip_set_req_version {
         unsigned int op;
diff --git a/net/netfilter/ipset/ip_set_core.c b/net/netfilter/ipset/ip_set_core.c
index f2e30fb31e78..428c30a8586f 100644
--- a/net/netfilter/ipset/ip_set_core.c
+++ b/net/netfilter/ipset/ip_set_core.c
@@ -1788,6 +1788,23 @@ ip_set_sockfn_get(struct sock *sk, int optval, void __user *user, int *len)
                 nfnl_unlock(NFNL_SUBSYS_IPSET);
                 goto copy;
         }
+        case IP_SET_OP_GET_FNAME: {
+                struct ip_set_req_get_set_family *req_get = data;
+                ip_set_id_t id;
+
+                if (*len != sizeof(struct ip_set_req_get_set_family)) {
+                        ret = -EINVAL;
+                        goto done;
+                }
+                req_get->set.name[IPSET_MAXNAMELEN - 1] = '\0';
+                nfnl_lock(NFNL_SUBSYS_IPSET);
+                find_set_and_id(req_get->set.name, &id);
+                req_get->set.index = id;
+                if (id != IPSET_INVALID_ID)
+                        req_get->family = nfnl_set(id)->family;
+                nfnl_unlock(NFNL_SUBSYS_IPSET);
+                goto copy;
+        }
         case IP_SET_OP_GET_BYINDEX: {
                 struct ip_set_req_get_set *req_get = data;
                 struct ip_set *set;