From 4fdb3bb723db469717c6d38fda667d8b0fa86ebd Mon Sep 17 00:00:00 2001 From: Harald Welte Date: Tue, 9 Aug 2005 19:40:55 -0700 Subject: [PATCH] [NETLINK]: Add properly module refcounting for kernel netlink sockets. - Remove bogus code for compiling netlink as module - Add module refcounting support for modules implementing a netlink protocol - Add support for autoloading modules that implement a netlink protocol as soon as someone opens a socket for that protocol Signed-off-by: Harald Welte Signed-off-by: David S. Miller --- drivers/w1/w1_int.c | 4 +- include/linux/net.h | 3 + include/linux/netlink.h | 2 +- kernel/audit.c | 3 +- lib/kobject_uevent.c | 3 +- net/bridge/netfilter/ebt_ulog.c | 2 +- net/core/rtnetlink.c | 2 +- net/decnet/netfilter/dn_rtmsg.c | 4 +- net/ipv4/fib_frontend.c | 2 +- net/ipv4/netfilter/ip_queue.c | 3 +- net/ipv4/netfilter/ipt_ULOG.c | 3 +- net/ipv4/tcp_diag.c | 3 +- net/ipv6/netfilter/ip6_queue.c | 2 +- net/netfilter/nfnetlink.c | 5 +- net/netlink/af_netlink.c | 108 +++++++++++++++++++++++++------- net/xfrm/xfrm_user.c | 4 +- security/selinux/netlink.c | 2 +- 17 files changed, 119 insertions(+), 36 deletions(-) diff --git a/drivers/w1/w1_int.c b/drivers/w1/w1_int.c index b5a5e04b6d37..8809788dac26 100644 --- a/drivers/w1/w1_int.c +++ b/drivers/w1/w1_int.c @@ -88,7 +88,7 @@ static struct w1_master * w1_alloc_dev(u32 id, int slave_count, int slave_ttl, dev->groups = 23; dev->seq = 1; - dev->nls = netlink_kernel_create(NETLINK_W1, NULL); + dev->nls = netlink_kernel_create(NETLINK_W1, NULL, THIS_MODULE); if (!dev->nls) { printk(KERN_ERR "Failed to create new netlink socket(%u) for w1 master %s.\n", NETLINK_NFLOG, dev->dev.bus_id); @@ -225,3 +225,5 @@ void w1_remove_master_device(struct w1_bus_master *bm) EXPORT_SYMBOL(w1_add_master_device); EXPORT_SYMBOL(w1_remove_master_device); + +MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_W1); diff --git a/include/linux/net.h b/include/linux/net.h index 20cb226b2268..39906619b9d7 100644 --- a/include/linux/net.h +++ b/include/linux/net.h @@ -282,5 +282,8 @@ static struct proto_ops name##_ops = { \ #define MODULE_ALIAS_NETPROTO(proto) \ MODULE_ALIAS("net-pf-" __stringify(proto)) +#define MODULE_ALIAS_NET_PF_PROTO(pf, proto) \ + MODULE_ALIAS("net-pf-" __stringify(pf) "-proto-" __stringify(proto)) + #endif /* __KERNEL__ */ #endif /* _LINUX_NET_H */ diff --git a/include/linux/netlink.h b/include/linux/netlink.h index 6552b71bfa73..1c50fea8995b 100644 --- a/include/linux/netlink.h +++ b/include/linux/netlink.h @@ -117,7 +117,7 @@ struct netlink_skb_parms #define NETLINK_CREDS(skb) (&NETLINK_CB((skb)).creds) -extern struct sock *netlink_kernel_create(int unit, void (*input)(struct sock *sk, int len)); +extern struct sock *netlink_kernel_create(int unit, void (*input)(struct sock *sk, int len), struct module *module); extern void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err); extern int netlink_unicast(struct sock *ssk, struct sk_buff *skb, __u32 pid, int nonblock); extern int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, __u32 pid, diff --git a/kernel/audit.c b/kernel/audit.c index ef35166fdc29..ed4019563d56 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -514,7 +514,8 @@ static int __init audit_init(void) { printk(KERN_INFO "audit: initializing netlink socket (%s)\n", audit_default ? "enabled" : "disabled"); - audit_sock = netlink_kernel_create(NETLINK_AUDIT, audit_receive); + audit_sock = netlink_kernel_create(NETLINK_AUDIT, audit_receive, + THIS_MODULE); if (!audit_sock) audit_panic("cannot initialize netlink socket"); diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c index 8e49d21057e4..88f4d746aa05 100644 --- a/lib/kobject_uevent.c +++ b/lib/kobject_uevent.c @@ -153,7 +153,8 @@ EXPORT_SYMBOL_GPL(kobject_uevent_atomic); static int __init kobject_uevent_init(void) { - uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, NULL); + uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, NULL, + THIS_MODULE); if (!uevent_sock) { printk(KERN_ERR diff --git a/net/bridge/netfilter/ebt_ulog.c b/net/bridge/netfilter/ebt_ulog.c index 01af4fcef26d..561d75c8ed5a 100644 --- a/net/bridge/netfilter/ebt_ulog.c +++ b/net/bridge/netfilter/ebt_ulog.c @@ -258,7 +258,7 @@ static int __init init(void) spin_lock_init(&ulog_buffers[i].lock); } - ebtulognl = netlink_kernel_create(NETLINK_NFLOG, NULL); + ebtulognl = netlink_kernel_create(NETLINK_NFLOG, NULL, THIS_MODULE); if (!ebtulognl) ret = -ENOMEM; else if ((ret = ebt_register_watcher(&ulog))) diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 4b1bb30e6381..9b3c61f1a37d 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -708,7 +708,7 @@ void __init rtnetlink_init(void) if (!rta_buf) panic("rtnetlink_init: cannot allocate rta_buf\n"); - rtnl = netlink_kernel_create(NETLINK_ROUTE, rtnetlink_rcv); + rtnl = netlink_kernel_create(NETLINK_ROUTE, rtnetlink_rcv, THIS_MODULE); if (rtnl == NULL) panic("rtnetlink_init: cannot initialize rtnetlink\n"); netlink_set_nonroot(NETLINK_ROUTE, NL_NONROOT_RECV); diff --git a/net/decnet/netfilter/dn_rtmsg.c b/net/decnet/netfilter/dn_rtmsg.c index 284a9998e53d..3068fddb2da3 100644 --- a/net/decnet/netfilter/dn_rtmsg.c +++ b/net/decnet/netfilter/dn_rtmsg.c @@ -138,7 +138,8 @@ static int __init init(void) { int rv = 0; - dnrmg = netlink_kernel_create(NETLINK_DNRTMSG, dnrmg_receive_user_sk); + dnrmg = netlink_kernel_create(NETLINK_DNRTMSG, dnrmg_receive_user_sk, + THIS_MODULE); if (dnrmg == NULL) { printk(KERN_ERR "dn_rtmsg: Cannot create netlink socket"); return -ENOMEM; @@ -162,6 +163,7 @@ static void __exit fini(void) MODULE_DESCRIPTION("DECnet Routing Message Grabulator"); MODULE_AUTHOR("Steven Whitehouse "); MODULE_LICENSE("GPL"); +MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_DNRTMSG); module_init(init); module_exit(fini); diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c index e5722084239b..b5e2f1550c91 100644 --- a/net/ipv4/fib_frontend.c +++ b/net/ipv4/fib_frontend.c @@ -567,7 +567,7 @@ static void nl_fib_input(struct sock *sk, int len) static void nl_fib_lookup_init(void) { - netlink_kernel_create(NETLINK_FIB_LOOKUP, nl_fib_input); + netlink_kernel_create(NETLINK_FIB_LOOKUP, nl_fib_input, THIS_MODULE); } static void fib_disable_ip(struct net_device *dev, int force) diff --git a/net/ipv4/netfilter/ip_queue.c b/net/ipv4/netfilter/ip_queue.c index ae975ac59c6a..b237f7fcad92 100644 --- a/net/ipv4/netfilter/ip_queue.c +++ b/net/ipv4/netfilter/ip_queue.c @@ -692,7 +692,8 @@ init_or_cleanup(int init) goto cleanup; netlink_register_notifier(&ipq_nl_notifier); - ipqnl = netlink_kernel_create(NETLINK_FIREWALL, ipq_rcv_sk); + ipqnl = netlink_kernel_create(NETLINK_FIREWALL, ipq_rcv_sk, + THIS_MODULE); if (ipqnl == NULL) { printk(KERN_ERR "ip_queue: failed to create netlink socket\n"); goto cleanup_netlink_notifier; diff --git a/net/ipv4/netfilter/ipt_ULOG.c b/net/ipv4/netfilter/ipt_ULOG.c index 52a0076302a7..4ea8371ab270 100644 --- a/net/ipv4/netfilter/ipt_ULOG.c +++ b/net/ipv4/netfilter/ipt_ULOG.c @@ -62,6 +62,7 @@ MODULE_LICENSE("GPL"); MODULE_AUTHOR("Harald Welte "); MODULE_DESCRIPTION("iptables userspace logging module"); +MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NFLOG); #define ULOG_NL_EVENT 111 /* Harald's favorite number */ #define ULOG_MAXNLGROUPS 32 /* numer of nlgroups */ @@ -372,7 +373,7 @@ static int __init init(void) ulog_buffers[i].timer.data = i; } - nflognl = netlink_kernel_create(NETLINK_NFLOG, NULL); + nflognl = netlink_kernel_create(NETLINK_NFLOG, NULL, THIS_MODULE); if (!nflognl) return -ENOMEM; diff --git a/net/ipv4/tcp_diag.c b/net/ipv4/tcp_diag.c index f66945cb158f..f79bd11a4701 100644 --- a/net/ipv4/tcp_diag.c +++ b/net/ipv4/tcp_diag.c @@ -774,7 +774,8 @@ static void tcpdiag_rcv(struct sock *sk, int len) static int __init tcpdiag_init(void) { - tcpnl = netlink_kernel_create(NETLINK_TCPDIAG, tcpdiag_rcv); + tcpnl = netlink_kernel_create(NETLINK_TCPDIAG, tcpdiag_rcv, + THIS_MODULE); if (tcpnl == NULL) return -ENOMEM; return 0; diff --git a/net/ipv6/netfilter/ip6_queue.c b/net/ipv6/netfilter/ip6_queue.c index 7130603a32c5..1c3d247a22cc 100644 --- a/net/ipv6/netfilter/ip6_queue.c +++ b/net/ipv6/netfilter/ip6_queue.c @@ -685,7 +685,7 @@ init_or_cleanup(int init) goto cleanup; netlink_register_notifier(&ipq_nl_notifier); - ipqnl = netlink_kernel_create(NETLINK_IP6_FW, ipq_rcv_sk); + ipqnl = netlink_kernel_create(NETLINK_IP6_FW, ipq_rcv_sk, THIS_MODULE); if (ipqnl == NULL) { printk(KERN_ERR "ip6_queue: failed to create netlink socket\n"); goto cleanup_netlink_notifier; diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c index b0ed57981847..6210ca42166c 100644 --- a/net/netfilter/nfnetlink.c +++ b/net/netfilter/nfnetlink.c @@ -38,6 +38,8 @@ #include MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Harald Welte "); +MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER); static char __initdata nfversion[] = "0.30"; @@ -324,7 +326,8 @@ int __init nfnetlink_init(void) { printk("Netfilter messages via NETLINK v%s.\n", nfversion); - nfnl = netlink_kernel_create(NETLINK_NETFILTER, nfnetlink_rcv); + nfnl = netlink_kernel_create(NETLINK_NETFILTER, nfnetlink_rcv, + THIS_MODULE); if (!nfnl) { printk(KERN_ERR "cannot initialize nfnetlink!\n"); return -1; diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index ff774a06c89d..5d487cd69c8c 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 * use nlk_sk, as sk->protinfo is on a diet 8) - * + * Fri Jul 22 19:51:12 MEST 2005 Harald Welte + * - 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 @@ -92,6 +97,7 @@ struct netlink_table { struct nl_pid_hash hash; struct hlist_head mc_list; unsigned int nl_nonroot; + struct proto_ops *p_ops; }; static struct netlink_table *nl_table; @@ -341,7 +347,21 @@ static int netlink_create(struct socket *sock, int protocol) if (protocol<0 || protocol >= MAX_LINKS) return -EPROTONOSUPPORT; - sock->ops = &netlink_ops; + netlink_table_grab(); + if (!nl_table[protocol].hash.entries) { +#ifdef CONFIG_KMOD + /* We do 'best effort'. If we find a matching module, + * it is loaded. If not, we don't return an error to + * allow pure userspace<->userspace communication. -HW + */ + netlink_table_ungrab(); + request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol); + netlink_table_grab(); +#endif + } + netlink_table_ungrab(); + + sock->ops = nl_table[protocol].p_ops; sk = sk_alloc(PF_NETLINK, GFP_KERNEL, &netlink_proto, 1); if (!sk) @@ -394,6 +414,22 @@ static int netlink_release(struct socket *sock) }; notifier_call_chain(&netlink_chain, NETLINK_URELEASE, &n); } + + /* When this is a kernel socket, we need to remove the owner pointer, + * since we don't know whether the module will be dying at any given + * point - HW + */ + if (!nlk->pid) { + struct proto_ops *p_tmp; + + netlink_table_grab(); + p_tmp = nl_table[sk->sk_protocol].p_ops; + if (p_tmp != &netlink_ops) { + nl_table[sk->sk_protocol].p_ops = &netlink_ops; + kfree(p_tmp); + } + netlink_table_ungrab(); + } sock_put(sk); return 0; @@ -1023,8 +1059,9 @@ static void netlink_data_ready(struct sock *sk, int len) */ struct sock * -netlink_kernel_create(int unit, void (*input)(struct sock *sk, int len)) +netlink_kernel_create(int unit, void (*input)(struct sock *sk, int len), struct module *module) { + struct proto_ops *p_ops; struct socket *sock; struct sock *sk; @@ -1034,22 +1071,63 @@ netlink_kernel_create(int unit, void (*input)(struct sock *sk, int len)) if (unit<0 || unit>=MAX_LINKS) return NULL; + /* Do a quick check, to make us not go down to netlink_insert() + * if protocol already has kernel socket. + */ + sk = netlink_lookup(unit, 0); + if (unlikely(sk)) { + sock_put(sk); + return NULL; + } + if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock)) return NULL; + sk = NULL; + if (module) { + /* Every registering protocol implemented in a module needs + * it's own p_ops, since the socket code cannot deal with + * module refcounting otherwise. -HW + */ + p_ops = kmalloc(sizeof(*p_ops), GFP_KERNEL); + if (!p_ops) + goto out_sock_release; + + memcpy(p_ops, &netlink_ops, sizeof(*p_ops)); + p_ops->owner = module; + } else + p_ops = &netlink_ops; + + netlink_table_grab(); + nl_table[unit].p_ops = p_ops; + netlink_table_ungrab(); + if (netlink_create(sock, unit) < 0) { - sock_release(sock); - return NULL; + sk = NULL; + goto out_kfree_p_ops; } + 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; + sk = NULL; + goto out_kfree_p_ops; } + + return sk; + +out_kfree_p_ops: + netlink_table_grab(); + if (nl_table[unit].p_ops != &netlink_ops) { + kfree(nl_table[unit].p_ops); + nl_table[unit].p_ops = &netlink_ops; + } + netlink_table_ungrab(); +out_sock_release: + sock_release(sock); return sk; } @@ -1413,6 +1491,8 @@ enomem: for (i = 0; i < MAX_LINKS; i++) { struct nl_pid_hash *hash = &nl_table[i].hash; + nl_table[i].p_ops = &netlink_ops; + hash->table = nl_pid_hash_alloc(1 * sizeof(*hash->table)); if (!hash->table) { while (i-- > 0) @@ -1438,21 +1518,7 @@ 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); diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c index 8da3e25b2c4c..33ceeea783b1 100644 --- a/net/xfrm/xfrm_user.c +++ b/net/xfrm/xfrm_user.c @@ -1519,7 +1519,8 @@ static int __init xfrm_user_init(void) { printk(KERN_INFO "Initializing IPsec netlink socket\n"); - xfrm_nl = netlink_kernel_create(NETLINK_XFRM, xfrm_netlink_rcv); + xfrm_nl = netlink_kernel_create(NETLINK_XFRM, xfrm_netlink_rcv, + THIS_MODULE); if (xfrm_nl == NULL) return -ENOMEM; @@ -1537,3 +1538,4 @@ static void __exit xfrm_user_exit(void) module_init(xfrm_user_init); module_exit(xfrm_user_exit); MODULE_LICENSE("GPL"); +MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_XFRM); diff --git a/security/selinux/netlink.c b/security/selinux/netlink.c index 18d08acafa78..341dbe2579be 100644 --- a/security/selinux/netlink.c +++ b/security/selinux/netlink.c @@ -103,7 +103,7 @@ void selnl_notify_policyload(u32 seqno) static int __init selnl_init(void) { - selnl = netlink_kernel_create(NETLINK_SELINUX, NULL); + selnl = netlink_kernel_create(NETLINK_SELINUX, NULL, THIS_MODULE); if (selnl == NULL) panic("SELinux: Cannot create netlink socket."); netlink_set_nonroot(NETLINK_SELINUX, NL_NONROOT_RECV);