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

This broke the pam audit module which includes an incorrect check for
-ENOENT instead of -EPROTONOTSUPP.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 62435ffc61846396e6a862dd9907319a1a3b8688..a64e1d5ce3ca8f38ae3cb76c41d62d4bd0a8d136 100644 (file)
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -398,24 +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;
@@ -534,6 +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;
@@ -545,8 +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)
@@ -559,7 +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();
@@ -620,7 +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;
 }
@@ -976,6 +995,11 @@ static int netlink_setsockopt(struct socket *sock, int level, int optname,
 
                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();
@@ -1483,8 +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,