1 files changed, 247 insertions, 65 deletions

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index ff774a06c89d..62435ffc6184 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -13,7 +13,12 @@
  *                               added netlink_proto_exit
  * Tue Jan 22 18:32:44 BRST 2002 Arnaldo C. de Melo <acme@conectiva.com.br>
  *                               use nlk_sk, as sk->protinfo is on a diet 8)
- *
+ * Fri Jul 22 19:51:12 MEST 2005 Harald Welte <laforge@gnumonks.org>
+ *                               - inc module use count of module that owns
+ *                                 the kernel socket in case userspace opens
+ *                                 socket of same protocol
+ *                               - remove all module support, since netlink is
+ *                                 mandatory if CONFIG_NET=y these days
  */
 
 #include <linux/config.h>
@@ -55,21 +60,29 @@
 #include <net/scm.h>
 
 #define Nprintk(a...)
+#define NLGRPSZ(x)      (ALIGN(x, sizeof(unsigned long) * 8) / 8)
 
 struct netlink_sock {
         /* struct sock has to be the first member of netlink_sock */
         struct sock             sk;
         u32                     pid;
-        unsigned int            groups;
         u32                     dst_pid;
-        unsigned int            dst_groups;
+        u32                     dst_group;
+        u32                     flags;
+        u32                     subscriptions;
+        u32                     ngroups;
+        unsigned long           *groups;
         unsigned long           state;
         wait_queue_head_t       wait;
         struct netlink_callback *cb;
         spinlock_t              cb_lock;
         void                    (*data_ready)(struct sock *sk, int bytes);
+        struct module           *module;
 };
 
+#define NETLINK_KERNEL_SOCKET   0x1
+#define NETLINK_RECV_PKTINFO    0x2
+
 static inline struct netlink_sock *nlk_sk(struct sock *sk)
 {
         return (struct netlink_sock *)sk;
@@ -92,6 +105,9 @@ struct netlink_table {
         struct nl_pid_hash hash;
         struct hlist_head mc_list;
         unsigned int nl_nonroot;
+        unsigned int groups;
+        struct module *module;
+        int registered;
 };
 
 static struct netlink_table *nl_table;
@@ -106,6 +122,11 @@ static atomic_t nl_table_users = ATOMIC_INIT(0);
 
 static struct notifier_block *netlink_chain;
 
+static u32 netlink_group_mask(u32 group)
+{
+        return group ? 1 << (group - 1) : 0;
+}
+
 static struct hlist_head *nl_pid_hashfn(struct nl_pid_hash *hash, u32 pid)
 {
         return &hash->table[jhash_1word(pid, hash->rnd) & hash->mask];
@@ -122,6 +143,7 @@ static void netlink_sock_destruct(struct sock *sk)
         BUG_TRAP(!atomic_read(&sk->sk_rmem_alloc));
         BUG_TRAP(!atomic_read(&sk->sk_wmem_alloc));
         BUG_TRAP(!nlk_sk(sk)->cb);
+        BUG_TRAP(!nlk_sk(sk)->groups);
 }
 
 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on SMP.
@@ -317,7 +339,7 @@ static void netlink_remove(struct sock *sk)
         netlink_table_grab();
         if (sk_del_node_init(sk))
                 nl_table[sk->sk_protocol].hash.entries--;
-        if (nlk_sk(sk)->groups)
+        if (nlk_sk(sk)->subscriptions)
                 __sk_del_bind_node(sk);
         netlink_table_ungrab();
 }
@@ -328,19 +350,11 @@ static struct proto netlink_proto = {
         .obj_size = sizeof(struct netlink_sock),
 };
 
-static int netlink_create(struct socket *sock, int protocol)
+static int __netlink_create(struct socket *sock, int protocol)
 {
         struct sock *sk;
         struct netlink_sock *nlk;
 
-        sock->state = SS_UNCONNECTED;
-
-        if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
-                return -ESOCKTNOSUPPORT;
-
-        if (protocol<0 || protocol >= MAX_LINKS)
-                return -EPROTONOSUPPORT;
-
         sock->ops = &netlink_ops;
 
         sk = sk_alloc(PF_NETLINK, GFP_KERNEL, &netlink_proto, 1);
@@ -350,15 +364,67 @@ static int netlink_create(struct socket *sock, int protocol)
         sock_init_data(sock, sk);
 
         nlk = nlk_sk(sk);
-
         spin_lock_init(&nlk->cb_lock);
         init_waitqueue_head(&nlk->wait);
-        sk->sk_destruct = netlink_sock_destruct;
 
+        sk->sk_destruct = netlink_sock_destruct;
         sk->sk_protocol = protocol;
         return 0;
 }
 
+static int netlink_create(struct socket *sock, int protocol)
+{
+        struct module *module = NULL;
+        struct netlink_sock *nlk;
+        unsigned int groups;
+        int err = 0;
+
+        sock->state = SS_UNCONNECTED;
+
+        if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
+                return -ESOCKTNOSUPPORT;
+
+        if (protocol<0 || protocol >= MAX_LINKS)
+                return -EPROTONOSUPPORT;
+
+        netlink_lock_table();
+#ifdef CONFIG_KMOD
+        if (!nl_table[protocol].registered) {
+                netlink_unlock_table();
+                request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
+                netlink_lock_table();
+        }
+#endif
+        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))
+                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;
+
+out_module:
+        module_put(module);
+        goto out;
+}
+
 static int netlink_release(struct socket *sock)
 {
         struct sock *sk = sock->sk;
@@ -387,14 +453,27 @@ static int netlink_release(struct socket *sock)
 
         skb_queue_purge(&sk->sk_write_queue);
 
-        if (nlk->pid && !nlk->groups) {
+        if (nlk->pid && !nlk->subscriptions) {
                 struct netlink_notify n = {
                                                 .protocol = sk->sk_protocol,
                                                 .pid = nlk->pid,
                                           };
                 notifier_call_chain(&netlink_chain, NETLINK_URELEASE, &n);
         }       
-        
+
+        if (nlk->module)
+                module_put(nlk->module);
+
+        if (nlk->flags & NETLINK_KERNEL_SOCKET) {
+                netlink_table_grab();
+                nl_table[sk->sk_protocol].module = NULL;
+                nl_table[sk->sk_protocol].registered = 0;
+                netlink_table_ungrab();
+        }
+
+        kfree(nlk->groups);
+        nlk->groups = NULL;
+
         sock_put(sk);
         return 0;
 }
@@ -443,6 +522,18 @@ static inline int netlink_capable(struct socket *sock, unsigned int flag)
                capable(CAP_NET_ADMIN);
 } 
 
+static void
+netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
+{
+        struct netlink_sock *nlk = nlk_sk(sk);
+
+        if (nlk->subscriptions && !subscriptions)
+                __sk_del_bind_node(sk);
+        else if (!nlk->subscriptions && subscriptions)
+                sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
+        nlk->subscriptions = subscriptions;
+}
+
 static int netlink_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
 {
         struct sock *sk = sock->sk;
@@ -468,15 +559,14 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr, int addr_len
                         return err;
         }
 
-        if (!nladdr->nl_groups && !nlk->groups)
+        if (!nladdr->nl_groups && !(u32)nlk->groups[0])
                 return 0;
 
         netlink_table_grab();
-        if (nlk->groups && !nladdr->nl_groups)
-                __sk_del_bind_node(sk);
-        else if (!nlk->groups && nladdr->nl_groups)
-                sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
-        nlk->groups = nladdr->nl_groups;
+        netlink_update_subscriptions(sk, nlk->subscriptions +
+                                         hweight32(nladdr->nl_groups) -
+                                         hweight32(nlk->groups[0]));
+        nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | nladdr->nl_groups; 
         netlink_table_ungrab();
 
         return 0;
@@ -493,7 +583,7 @@ static int netlink_connect(struct socket *sock, struct sockaddr *addr,
         if (addr->sa_family == AF_UNSPEC) {
                 sk->sk_state    = NETLINK_UNCONNECTED;
                 nlk->dst_pid    = 0;
-                nlk->dst_groups = 0;
+                nlk->dst_group  = 0;
                 return 0;
         }
         if (addr->sa_family != AF_NETLINK)
@@ -509,7 +599,7 @@ static int netlink_connect(struct socket *sock, struct sockaddr *addr,
         if (err == 0) {
                 sk->sk_state    = NETLINK_CONNECTED;
                 nlk->dst_pid    = nladdr->nl_pid;
-                nlk->dst_groups = nladdr->nl_groups;
+                nlk->dst_group  = ffs(nladdr->nl_groups);
         }
 
         return err;
@@ -527,10 +617,10 @@ static int netlink_getname(struct socket *sock, struct sockaddr *addr, int *addr
 
         if (peer) {
                 nladdr->nl_pid = nlk->dst_pid;
-                nladdr->nl_groups = nlk->dst_groups;
+                nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
         } else {
                 nladdr->nl_pid = nlk->pid;
-                nladdr->nl_groups = nlk->groups;
+                nladdr->nl_groups = nlk->groups[0];
         }
         return 0;
 }
@@ -731,7 +821,8 @@ static inline int do_one_broadcast(struct sock *sk,
         if (p->exclude_sk == sk)
                 goto out;
 
-        if (nlk->pid == p->pid || !(nlk->groups & p->group))
+        if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
+            !test_bit(p->group - 1, nlk->groups))
                 goto out;
 
         if (p->failure) {
@@ -770,7 +861,7 @@ 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;
@@ -827,7 +918,8 @@ static inline int do_one_set_err(struct sock *sk,
         if (sk == p->exclude_sk)
                 goto out;
 
-        if (nlk->pid == p->pid || !(nlk->groups & p->group))
+        if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
+            !test_bit(p->group - 1, nlk->groups))
                 goto out;
 
         sk->sk_err = p->code;
@@ -855,6 +947,94 @@ 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 (!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);
@@ -873,7 +1053,7 @@ static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
         struct netlink_sock *nlk = nlk_sk(sk);
         struct sockaddr_nl *addr=msg->msg_name;
         u32 dst_pid;
-        u32 dst_groups;
+        u32 dst_group;
         struct sk_buff *skb;
         int err;
         struct scm_cookie scm;
@@ -891,12 +1071,12 @@ static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
                 if (addr->nl_family != AF_NETLINK)
                         return -EINVAL;
                 dst_pid = addr->nl_pid;
-                dst_groups = addr->nl_groups;
-                if (dst_groups && !netlink_capable(sock, NL_NONROOT_SEND))
+                dst_group = ffs(addr->nl_groups);
+                if (dst_group && !netlink_capable(sock, NL_NONROOT_SEND))
                         return -EPERM;
         } else {
                 dst_pid = nlk->dst_pid;
-                dst_groups = nlk->dst_groups;
+                dst_group = nlk->dst_group;
         }
 
         if (!nlk->pid) {
@@ -914,9 +1094,8 @@ static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
                 goto out;
 
         NETLINK_CB(skb).pid     = nlk->pid;
-        NETLINK_CB(skb).groups  = nlk->groups;
         NETLINK_CB(skb).dst_pid = dst_pid;
-        NETLINK_CB(skb).dst_groups = dst_groups;
+        NETLINK_CB(skb).dst_group = dst_group;
         NETLINK_CB(skb).loginuid = audit_get_loginuid(current->audit_context);
         memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
 
@@ -938,9 +1117,9 @@ static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
                 goto out;
         }
 
-        if (dst_groups) {
+        if (dst_group) {
                 atomic_inc(&skb->users);
-                netlink_broadcast(sk, skb, dst_pid, dst_groups, GFP_KERNEL);
+                netlink_broadcast(sk, skb, dst_pid, dst_group, GFP_KERNEL);
         }
         err = netlink_unicast(sk, skb, dst_pid, msg->msg_flags&MSG_DONTWAIT);
 
@@ -986,7 +1165,7 @@ static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
                 addr->nl_family = AF_NETLINK;
                 addr->nl_pad    = 0;
                 addr->nl_pid    = NETLINK_CB(skb).pid;
-                addr->nl_groups = NETLINK_CB(skb).dst_groups;
+                addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
                 msg->msg_namelen = sizeof(*addr);
         }
 
@@ -1001,6 +1180,8 @@ 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);
@@ -1023,10 +1204,13 @@ static void netlink_data_ready(struct sock *sk, int len)
  */
 
 struct sock *
-netlink_kernel_create(int unit, void (*input)(struct sock *sk, int len))
+netlink_kernel_create(int unit, unsigned int groups,
+                      void (*input)(struct sock *sk, int len),
+                      struct module *module)
 {
         struct socket *sock;
         struct sock *sk;
+        struct netlink_sock *nlk;
 
         if (!nl_table)
                 return NULL;
@@ -1037,20 +1221,31 @@ netlink_kernel_create(int unit, void (*input)(struct sock *sk, int len))
         if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
                 return NULL;
 
-        if (netlink_create(sock, unit) < 0) {
-                sock_release(sock);
-                return NULL;
-        }
+        if (__netlink_create(sock, unit) < 0)
+                goto out_sock_release;
+
         sk = sock->sk;
         sk->sk_data_ready = netlink_data_ready;
         if (input)
                 nlk_sk(sk)->data_ready = input;
 
-        if (netlink_insert(sk, 0)) {
-                sock_release(sock);
-                return NULL;
-        }
+        if (netlink_insert(sk, 0))
+                goto out_sock_release;
+
+        nlk = nlk_sk(sk);
+        nlk->flags |= NETLINK_KERNEL_SOCKET;
+
+        netlink_table_grab();
+        nl_table[unit].groups = groups < 32 ? 32 : groups;
+        nl_table[unit].module = module;
+        nl_table[unit].registered = 1;
+        netlink_table_ungrab();
+
         return sk;
+
+out_sock_release:
+        sock_release(sock);
+        return NULL;
 }
 
 void netlink_set_nonroot(int protocol, unsigned int flags)
@@ -1288,7 +1483,8 @@ static int netlink_seq_show(struct seq_file *seq, void *v)
                            s,
                            s->sk_protocol,
                            nlk->pid,
-                           nlk->groups,
+                           nlk->flags & NETLINK_KERNEL_SOCKET ?
+                                0 : (unsigned int)nlk->groups[0],
                            atomic_read(&s->sk_rmem_alloc),
                            atomic_read(&s->sk_wmem_alloc),
                            nlk->cb,
@@ -1362,8 +1558,8 @@ 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,
@@ -1438,21 +1634,7 @@ out:
         return err;
 }
 
-static void __exit netlink_proto_exit(void)
-{
-        sock_unregister(PF_NETLINK);
-        proc_net_remove("netlink");
-        kfree(nl_table);
-        nl_table = NULL;
-        proto_unregister(&netlink_proto);
-}
-
 core_initcall(netlink_proto_init);
-module_exit(netlink_proto_exit);
-
-MODULE_LICENSE("GPL");
-
-MODULE_ALIAS_NETPROTO(PF_NETLINK);
 
 EXPORT_SYMBOL(netlink_ack);
 EXPORT_SYMBOL(netlink_broadcast);