[NETLINK]: Don't prevent creating sockets when no kernel socket is registered

[linux-2.6] / net / netlink / af_netlink.c

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 58d4ca42ac32a0c2ca71d392af7e58e78f799463..a64e1d5ce3ca8f38ae3cb76c41d62d4bd0a8d136 100644 (file)
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -81,6 +81,7 @@ struct netlink_sock {
 };
 
 #define NETLINK_KERNEL_SOCKET  0x1
+#define NETLINK_RECV_PKTINFO   0x2
 
 static inline struct netlink_sock *nlk_sk(struct sock *sk)
 {
@@ -397,24 +398,13 @@ static int netlink_create(struct socket *sock, int protocol)
        if (nl_table[protocol].registered &&
            try_module_get(nl_table[protocol].module))
                module = nl_table[protocol].module;
-       else
-               err = -EPROTONOSUPPORT;
        groups = nl_table[protocol].groups;
        netlink_unlock_table();
 
-       if (err || (err = __netlink_create(sock, protocol) < 0))
+       if ((err = __netlink_create(sock, protocol) < 0))
                goto out_module;
 
        nlk = nlk_sk(sock->sk);
-
-       nlk->groups = kmalloc(NLGRPSZ(groups), GFP_KERNEL);
-       if (nlk->groups == NULL) {
-               err = -ENOMEM;
-               goto out_module;
-       }
-       memset(nlk->groups, 0, NLGRPSZ(groups));
-       nlk->ngroups = groups;
-
        nlk->module = module;
 out:
        return err;
@@ -533,6 +523,29 @@ netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
        nlk->subscriptions = subscriptions;
 }
 
+static int netlink_alloc_groups(struct sock *sk)
+{
+       struct netlink_sock *nlk = nlk_sk(sk);
+       unsigned int groups;
+       int err = 0;
+
+       netlink_lock_table();
+       groups = nl_table[sk->sk_protocol].groups;
+       if (!nl_table[sk->sk_protocol].registered)
+               err = -ENOENT;
+       netlink_unlock_table();
+
+       if (err)
+               return err;
+
+       nlk->groups = kmalloc(NLGRPSZ(groups), GFP_KERNEL);
+       if (nlk->groups == NULL)
+               return -ENOMEM;
+       memset(nlk->groups, 0, NLGRPSZ(groups));
+       nlk->ngroups = groups;
+       return 0;
+}
+
 static int netlink_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
 {
        struct sock *sk = sock->sk;
@@ -544,8 +557,15 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr, int addr_len
                return -EINVAL;
 
        /* Only superuser is allowed to listen multicasts */
-       if (nladdr->nl_groups && !netlink_capable(sock, NL_NONROOT_RECV))
-               return -EPERM;
+       if (nladdr->nl_groups) {
+               if (!netlink_capable(sock, NL_NONROOT_RECV))
+                       return -EPERM;
+               if (nlk->groups == NULL) {
+                       err = netlink_alloc_groups(sk);
+                       if (err)
+                               return err;
+               }
+       }
 
        if (nlk->pid) {
                if (nladdr->nl_pid != nlk->pid)
@@ -558,7 +578,7 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr, int addr_len
                        return err;
        }
 
-       if (!nladdr->nl_groups && !(u32)nlk->groups[0])
+       if (!nladdr->nl_groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
                return 0;
 
        netlink_table_grab();
@@ -619,7 +639,7 @@ static int netlink_getname(struct socket *sock, struct sockaddr *addr, int *addr
                nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
        } else {
                nladdr->nl_pid = nlk->pid;
-               nladdr->nl_groups = nlk->groups[0];
+               nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
        }
        return 0;
 }
@@ -860,7 +880,7 @@ out:
 }
 
 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid,
-                     u32 group, int allocation)
+                     u32 group, unsigned int __nocast allocation)
 {
        struct netlink_broadcast_data info;
        struct hlist_node *node;
@@ -946,6 +966,99 @@ void netlink_set_err(struct sock *ssk, u32 pid, u32 group, int code)
        read_unlock(&nl_table_lock);
 }
 
+static int netlink_setsockopt(struct socket *sock, int level, int optname,
+                              char __user *optval, int optlen)
+{
+       struct sock *sk = sock->sk;
+       struct netlink_sock *nlk = nlk_sk(sk);
+       int val = 0, err;
+
+       if (level != SOL_NETLINK)
+               return -ENOPROTOOPT;
+
+       if (optlen >= sizeof(int) &&
+           get_user(val, (int __user *)optval))
+               return -EFAULT;
+
+       switch (optname) {
+       case NETLINK_PKTINFO:
+               if (val)
+                       nlk->flags |= NETLINK_RECV_PKTINFO;
+               else
+                       nlk->flags &= ~NETLINK_RECV_PKTINFO;
+               err = 0;
+               break;
+       case NETLINK_ADD_MEMBERSHIP:
+       case NETLINK_DROP_MEMBERSHIP: {
+               unsigned int subscriptions;
+               int old, new = optname == NETLINK_ADD_MEMBERSHIP ? 1 : 0;
+
+               if (!netlink_capable(sock, NL_NONROOT_RECV))
+                       return -EPERM;
+               if (nlk->groups == NULL) {
+                       err = netlink_alloc_groups(sk);
+                       if (err)
+                               return err;
+               }
+               if (!val || val - 1 >= nlk->ngroups)
+                       return -EINVAL;
+               netlink_table_grab();
+               old = test_bit(val - 1, nlk->groups);
+               subscriptions = nlk->subscriptions - old + new;
+               if (new)
+                       __set_bit(val - 1, nlk->groups);
+               else
+                       __clear_bit(val - 1, nlk->groups);
+               netlink_update_subscriptions(sk, subscriptions);
+               netlink_table_ungrab();
+               err = 0;
+               break;
+       }
+       default:
+               err = -ENOPROTOOPT;
+       }
+       return err;
+}
+
+static int netlink_getsockopt(struct socket *sock, int level, int optname,
+                              char __user *optval, int __user *optlen)
+{
+       struct sock *sk = sock->sk;
+       struct netlink_sock *nlk = nlk_sk(sk);
+       int len, val, err;
+
+       if (level != SOL_NETLINK)
+               return -ENOPROTOOPT;
+
+       if (get_user(len, optlen))
+               return -EFAULT;
+       if (len < 0)
+               return -EINVAL;
+
+       switch (optname) {
+       case NETLINK_PKTINFO:
+               if (len < sizeof(int))
+                       return -EINVAL;
+               len = sizeof(int);
+               val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0;
+               put_user(len, optlen);
+               put_user(val, optval);
+               err = 0;
+               break;
+       default:
+               err = -ENOPROTOOPT;
+       }
+       return err;
+}
+
+static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
+{
+       struct nl_pktinfo info;
+
+       info.group = NETLINK_CB(skb).dst_group;
+       put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
+}
+
 static inline void netlink_rcv_wake(struct sock *sk)
 {
        struct netlink_sock *nlk = nlk_sk(sk);
@@ -1091,6 +1204,8 @@ static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
                netlink_dump(sk);
 
        scm_recv(sock, msg, siocb->scm, flags);
+       if (nlk->flags & NETLINK_RECV_PKTINFO)
+               netlink_cmsg_recv_pktinfo(msg, skb);
 
 out:
        netlink_rcv_wake(sk);
@@ -1113,7 +1228,9 @@ static void netlink_data_ready(struct sock *sk, int len)
  */
 
 struct sock *
-netlink_kernel_create(int unit, void (*input)(struct sock *sk, int len), struct module *module)
+netlink_kernel_create(int unit, unsigned int groups,
+                      void (*input)(struct sock *sk, int len),
+                      struct module *module)
 {
        struct socket *sock;
        struct sock *sk;
@@ -1143,7 +1260,7 @@ netlink_kernel_create(int unit, void (*input)(struct sock *sk, int len), struct
        nlk->flags |= NETLINK_KERNEL_SOCKET;
 
        netlink_table_grab();
-       nl_table[unit].groups = 32;
+       nl_table[unit].groups = groups < 32 ? 32 : groups;
        nl_table[unit].module = module;
        nl_table[unit].registered = 1;
        netlink_table_ungrab();
@@ -1390,8 +1507,7 @@ static int netlink_seq_show(struct seq_file *seq, void *v)
                           s,
                           s->sk_protocol,
                           nlk->pid,
-                          nlk->flags & NETLINK_KERNEL_SOCKET ?
-                               0 : (unsigned int)nlk->groups[0],
+                          nlk->groups ? (u32)nlk->groups[0] : 0,
                           atomic_read(&s->sk_rmem_alloc),
                           atomic_read(&s->sk_wmem_alloc),
                           nlk->cb,
@@ -1465,8 +1581,8 @@ static struct proto_ops netlink_ops = {
        .ioctl =        sock_no_ioctl,
        .listen =       sock_no_listen,
        .shutdown =     sock_no_shutdown,
-       .setsockopt =   sock_no_setsockopt,
-       .getsockopt =   sock_no_getsockopt,
+       .setsockopt =   netlink_setsockopt,
+       .getsockopt =   netlink_getsockopt,
        .sendmsg =      netlink_sendmsg,
        .recvmsg =      netlink_recvmsg,
        .mmap =         sock_no_mmap,