4 files changed, 56 insertions, 24 deletions

diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index aad8eeaf416d..5146ce066498 100644
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -45,7 +45,8 @@ struct netlink_kernel_cfg {
         unsigned int    flags;
         void            (*input)(struct sk_buff *skb);
         struct mutex    *cb_mutex;
-        void            (*bind)(int group);
+        int             (*bind)(int group);
+        void            (*unbind)(int group);
         bool            (*compare)(struct net *net, struct sock *sk);
 };
 
diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c
index 0df800a454ec..6e42dcfad40a 100644
--- a/net/netfilter/nfnetlink.c
+++ b/net/netfilter/nfnetlink.c
@@ -400,7 +400,7 @@ static void nfnetlink_rcv(struct sk_buff *skb)
 }
 
 #ifdef CONFIG_MODULES
-static void nfnetlink_bind(int group)
+static int nfnetlink_bind(int group)
 {
         const struct nfnetlink_subsystem *ss;
         int type = nfnl_group2type[group];
@@ -410,6 +410,7 @@ static void nfnetlink_bind(int group)
         rcu_read_unlock();
         if (!ss)
                 request_module("nfnetlink-subsys-%d", type);
+        return 0;
 }
 #endif
 
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 894cda0206bb..7e8d229bc010 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1206,7 +1206,8 @@ static int netlink_create(struct net *net, struct socket *sock, int protocol,
         struct module *module = NULL;
         struct mutex *cb_mutex;
         struct netlink_sock *nlk;
-        void (*bind)(int group);
+        int (*bind)(int group);
+        void (*unbind)(int group);
         int err = 0;
 
         sock->state = SS_UNCONNECTED;
@@ -1232,6 +1233,7 @@ static int netlink_create(struct net *net, struct socket *sock, int protocol,
                 err = -EPROTONOSUPPORT;
         cb_mutex = nl_table[protocol].cb_mutex;
         bind = nl_table[protocol].bind;
+        unbind = nl_table[protocol].unbind;
         netlink_unlock_table();
 
         if (err < 0)
@@ -1248,6 +1250,7 @@ static int netlink_create(struct net *net, struct socket *sock, int protocol,
         nlk = nlk_sk(sock->sk);
         nlk->module = module;
         nlk->netlink_bind = bind;
+        nlk->netlink_unbind = unbind;
 out:
         return err;
 
@@ -1301,6 +1304,7 @@ static int netlink_release(struct socket *sock)
                         kfree_rcu(old, rcu);
                         nl_table[sk->sk_protocol].module = NULL;
                         nl_table[sk->sk_protocol].bind = NULL;
+                        nl_table[sk->sk_protocol].unbind = NULL;
                         nl_table[sk->sk_protocol].flags = 0;
                         nl_table[sk->sk_protocol].registered = 0;
                 }
@@ -1411,6 +1415,19 @@ static int netlink_realloc_groups(struct sock *sk)
         return err;
 }
 
+static void netlink_unbind(int group, long unsigned int groups,
+                           struct netlink_sock *nlk)
+{
+        int undo;
+
+        if (!nlk->netlink_unbind)
+                return;
+
+        for (undo = 0; undo < group; undo++)
+                if (test_bit(group, &groups))
+                        nlk->netlink_unbind(undo);
+}
+
 static int netlink_bind(struct socket *sock, struct sockaddr *addr,
                         int addr_len)
 {
@@ -1419,6 +1436,7 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr,
         struct netlink_sock *nlk = nlk_sk(sk);
         struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
         int err;
+        long unsigned int groups = nladdr->nl_groups;
 
         if (addr_len < sizeof(struct sockaddr_nl))
                 return -EINVAL;
@@ -1427,7 +1445,7 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr,
                 return -EINVAL;
 
         /* Only superuser is allowed to listen multicasts */
-        if (nladdr->nl_groups) {
+        if (groups) {
                 if (!netlink_capable(sock, NL_CFG_F_NONROOT_RECV))
                         return -EPERM;
                 err = netlink_realloc_groups(sk);
@@ -1435,37 +1453,45 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr,
                         return err;
         }
 
-        if (nlk->portid) {
+        if (nlk->portid)
                 if (nladdr->nl_pid != nlk->portid)
                         return -EINVAL;
-        } else {
+
+        if (nlk->netlink_bind && groups) {
+                int group;
+
+                for (group = 0; group < nlk->ngroups; group++) {
+                        if (!test_bit(group, &groups))
+                                continue;
+                        err = nlk->netlink_bind(group);
+                        if (!err)
+                                continue;
+                        netlink_unbind(group, groups, nlk);
+                        return err;
+                }
+        }
+
+        if (!nlk->portid) {
                 err = nladdr->nl_pid ?
                         netlink_insert(sk, net, nladdr->nl_pid) :
                         netlink_autobind(sock);
-                if (err)
+                if (err) {
+                        netlink_unbind(nlk->ngroups - 1, groups, nlk);
                         return err;
+                }
         }
 
-        if (!nladdr->nl_groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
+        if (!groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
                 return 0;
 
         netlink_table_grab();
         netlink_update_subscriptions(sk, nlk->subscriptions +
-                                         hweight32(nladdr->nl_groups) -
+                                         hweight32(groups) -
                                          hweight32(nlk->groups[0]));
-        nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | nladdr->nl_groups;
+        nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | groups;
         netlink_update_listeners(sk);
         netlink_table_ungrab();
 
-        if (nlk->netlink_bind && nlk->groups[0]) {
-                int i;
-
-                for (i = 0; i < nlk->ngroups; i++) {
-                        if (test_bit(i, nlk->groups))
-                                nlk->netlink_bind(i);
-                }
-        }
-
         return 0;
 }
 
@@ -2103,14 +2129,16 @@ static int netlink_setsockopt(struct socket *sock, int level, int optname,
                         return err;
                 if (!val || val - 1 >= nlk->ngroups)
                         return -EINVAL;
+                if (nlk->netlink_bind) {
+                        err = nlk->netlink_bind(val);
+                        if (err)
+                                return err;
+                }
                 netlink_table_grab();
                 netlink_update_socket_mc(nlk, val,
                                          optname == NETLINK_ADD_MEMBERSHIP);
                 netlink_table_ungrab();
 
-                if (nlk->netlink_bind)
-                        nlk->netlink_bind(val);
-
                 err = 0;
                 break;
         }
diff --git a/net/netlink/af_netlink.h b/net/netlink/af_netlink.h
index ed13a790b00e..0b59d441f5b6 100644
--- a/net/netlink/af_netlink.h
+++ b/net/netlink/af_netlink.h
@@ -38,7 +38,8 @@ struct netlink_sock {
         struct mutex            *cb_mutex;
         struct mutex            cb_def_mutex;
         void                    (*netlink_rcv)(struct sk_buff *skb);
-        void                    (*netlink_bind)(int group);
+        int                     (*netlink_bind)(int group);
+        void                    (*netlink_unbind)(int group);
         struct module           *module;
 #ifdef CONFIG_NETLINK_MMAP
         struct mutex            pg_vec_lock;
@@ -74,7 +75,8 @@ struct netlink_table {
         unsigned int            groups;
         struct mutex            *cb_mutex;
         struct module           *module;
-        void                    (*bind)(int group);
+        int                     (*bind)(int group);
+        void                    (*unbind)(int group);
         bool                    (*compare)(struct net *net, struct sock *sock);
         int                     registered;
 };