| /* Netfilter messages via netlink socket. Allows for user space |
| * protocol helpers and general trouble making from userspace. |
| * |
| * (C) 2001 by Jay Schulist <jschlst@samba.org>, |
| * (C) 2002-2005 by Harald Welte <laforge@gnumonks.org> |
| * (C) 2005,2007 by Pablo Neira Ayuso <pablo@netfilter.org> |
| * |
| * Initial netfilter messages via netlink development funded and |
| * generally made possible by Network Robots, Inc. (www.networkrobots.com) |
| * |
| * Further development of this code funded by Astaro AG (http://www.astaro.com) |
| * |
| * This software may be used and distributed according to the terms |
| * of the GNU General Public License, incorporated herein by reference. |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/types.h> |
| #include <linux/socket.h> |
| #include <linux/kernel.h> |
| #include <linux/string.h> |
| #include <linux/sockios.h> |
| #include <linux/net.h> |
| #include <linux/skbuff.h> |
| #include <linux/uaccess.h> |
| #include <net/sock.h> |
| #include <linux/init.h> |
| |
| #include <net/netlink.h> |
| #include <linux/netfilter/nfnetlink.h> |
| |
| MODULE_LICENSE("GPL"); |
| MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); |
| MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER); |
| |
| #define nfnl_dereference_protected(id) \ |
| rcu_dereference_protected(table[(id)].subsys, \ |
| lockdep_nfnl_is_held((id))) |
| |
| static char __initdata nfversion[] = "0.30"; |
| |
| static struct { |
| struct mutex mutex; |
| const struct nfnetlink_subsystem __rcu *subsys; |
| } table[NFNL_SUBSYS_COUNT]; |
| |
| static const int nfnl_group2type[NFNLGRP_MAX+1] = { |
| [NFNLGRP_CONNTRACK_NEW] = NFNL_SUBSYS_CTNETLINK, |
| [NFNLGRP_CONNTRACK_UPDATE] = NFNL_SUBSYS_CTNETLINK, |
| [NFNLGRP_CONNTRACK_DESTROY] = NFNL_SUBSYS_CTNETLINK, |
| [NFNLGRP_CONNTRACK_EXP_NEW] = NFNL_SUBSYS_CTNETLINK_EXP, |
| [NFNLGRP_CONNTRACK_EXP_UPDATE] = NFNL_SUBSYS_CTNETLINK_EXP, |
| [NFNLGRP_CONNTRACK_EXP_DESTROY] = NFNL_SUBSYS_CTNETLINK_EXP, |
| [NFNLGRP_NFTABLES] = NFNL_SUBSYS_NFTABLES, |
| [NFNLGRP_ACCT_QUOTA] = NFNL_SUBSYS_ACCT, |
| [NFNLGRP_NFTRACE] = NFNL_SUBSYS_NFTABLES, |
| }; |
| |
| void nfnl_lock(__u8 subsys_id) |
| { |
| mutex_lock(&table[subsys_id].mutex); |
| } |
| EXPORT_SYMBOL_GPL(nfnl_lock); |
| |
| void nfnl_unlock(__u8 subsys_id) |
| { |
| mutex_unlock(&table[subsys_id].mutex); |
| } |
| EXPORT_SYMBOL_GPL(nfnl_unlock); |
| |
| #ifdef CONFIG_PROVE_LOCKING |
| bool lockdep_nfnl_is_held(u8 subsys_id) |
| { |
| return lockdep_is_held(&table[subsys_id].mutex); |
| } |
| EXPORT_SYMBOL_GPL(lockdep_nfnl_is_held); |
| #endif |
| |
| int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n) |
| { |
| nfnl_lock(n->subsys_id); |
| if (table[n->subsys_id].subsys) { |
| nfnl_unlock(n->subsys_id); |
| return -EBUSY; |
| } |
| rcu_assign_pointer(table[n->subsys_id].subsys, n); |
| nfnl_unlock(n->subsys_id); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(nfnetlink_subsys_register); |
| |
| int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n) |
| { |
| nfnl_lock(n->subsys_id); |
| table[n->subsys_id].subsys = NULL; |
| nfnl_unlock(n->subsys_id); |
| synchronize_rcu(); |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister); |
| |
| static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u_int16_t type) |
| { |
| u_int8_t subsys_id = NFNL_SUBSYS_ID(type); |
| |
| if (subsys_id >= NFNL_SUBSYS_COUNT) |
| return NULL; |
| |
| return rcu_dereference(table[subsys_id].subsys); |
| } |
| |
| static inline const struct nfnl_callback * |
| nfnetlink_find_client(u_int16_t type, const struct nfnetlink_subsystem *ss) |
| { |
| u_int8_t cb_id = NFNL_MSG_TYPE(type); |
| |
| if (cb_id >= ss->cb_count) |
| return NULL; |
| |
| return &ss->cb[cb_id]; |
| } |
| |
| int nfnetlink_has_listeners(struct net *net, unsigned int group) |
| { |
| return netlink_has_listeners(net->nfnl, group); |
| } |
| EXPORT_SYMBOL_GPL(nfnetlink_has_listeners); |
| |
| int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 portid, |
| unsigned int group, int echo, gfp_t flags) |
| { |
| return nlmsg_notify(net->nfnl, skb, portid, group, echo, flags); |
| } |
| EXPORT_SYMBOL_GPL(nfnetlink_send); |
| |
| int nfnetlink_set_err(struct net *net, u32 portid, u32 group, int error) |
| { |
| return netlink_set_err(net->nfnl, portid, group, error); |
| } |
| EXPORT_SYMBOL_GPL(nfnetlink_set_err); |
| |
| int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u32 portid, |
| int flags) |
| { |
| return netlink_unicast(net->nfnl, skb, portid, flags); |
| } |
| EXPORT_SYMBOL_GPL(nfnetlink_unicast); |
| |
| /* Process one complete nfnetlink message. */ |
| static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) |
| { |
| struct net *net = sock_net(skb->sk); |
| const struct nfnl_callback *nc; |
| const struct nfnetlink_subsystem *ss; |
| int type, err; |
| |
| /* All the messages must at least contain nfgenmsg */ |
| if (nlmsg_len(nlh) < sizeof(struct nfgenmsg)) |
| return 0; |
| |
| type = nlh->nlmsg_type; |
| replay: |
| rcu_read_lock(); |
| ss = nfnetlink_get_subsys(type); |
| if (!ss) { |
| #ifdef CONFIG_MODULES |
| rcu_read_unlock(); |
| request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type)); |
| rcu_read_lock(); |
| ss = nfnetlink_get_subsys(type); |
| if (!ss) |
| #endif |
| { |
| rcu_read_unlock(); |
| return -EINVAL; |
| } |
| } |
| |
| nc = nfnetlink_find_client(type, ss); |
| if (!nc) { |
| rcu_read_unlock(); |
| return -EINVAL; |
| } |
| |
| { |
| int min_len = nlmsg_total_size(sizeof(struct nfgenmsg)); |
| u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type); |
| struct nlattr *cda[ss->cb[cb_id].attr_count + 1]; |
| struct nlattr *attr = (void *)nlh + min_len; |
| int attrlen = nlh->nlmsg_len - min_len; |
| __u8 subsys_id = NFNL_SUBSYS_ID(type); |
| |
| err = nla_parse(cda, ss->cb[cb_id].attr_count, |
| attr, attrlen, ss->cb[cb_id].policy); |
| if (err < 0) { |
| rcu_read_unlock(); |
| return err; |
| } |
| |
| if (nc->call_rcu) { |
| err = nc->call_rcu(net, net->nfnl, skb, nlh, |
| (const struct nlattr **)cda); |
| rcu_read_unlock(); |
| } else { |
| rcu_read_unlock(); |
| nfnl_lock(subsys_id); |
| if (nfnl_dereference_protected(subsys_id) != ss || |
| nfnetlink_find_client(type, ss) != nc) |
| err = -EAGAIN; |
| else if (nc->call) |
| err = nc->call(net, net->nfnl, skb, nlh, |
| (const struct nlattr **)cda); |
| else |
| err = -EINVAL; |
| nfnl_unlock(subsys_id); |
| } |
| if (err == -EAGAIN) |
| goto replay; |
| return err; |
| } |
| } |
| |
| struct nfnl_err { |
| struct list_head head; |
| struct nlmsghdr *nlh; |
| int err; |
| }; |
| |
| static int nfnl_err_add(struct list_head *list, struct nlmsghdr *nlh, int err) |
| { |
| struct nfnl_err *nfnl_err; |
| |
| nfnl_err = kmalloc(sizeof(struct nfnl_err), GFP_KERNEL); |
| if (nfnl_err == NULL) |
| return -ENOMEM; |
| |
| nfnl_err->nlh = nlh; |
| nfnl_err->err = err; |
| list_add_tail(&nfnl_err->head, list); |
| |
| return 0; |
| } |
| |
| static void nfnl_err_del(struct nfnl_err *nfnl_err) |
| { |
| list_del(&nfnl_err->head); |
| kfree(nfnl_err); |
| } |
| |
| static void nfnl_err_reset(struct list_head *err_list) |
| { |
| struct nfnl_err *nfnl_err, *next; |
| |
| list_for_each_entry_safe(nfnl_err, next, err_list, head) |
| nfnl_err_del(nfnl_err); |
| } |
| |
| static void nfnl_err_deliver(struct list_head *err_list, struct sk_buff *skb) |
| { |
| struct nfnl_err *nfnl_err, *next; |
| |
| list_for_each_entry_safe(nfnl_err, next, err_list, head) { |
| netlink_ack(skb, nfnl_err->nlh, nfnl_err->err); |
| nfnl_err_del(nfnl_err); |
| } |
| } |
| |
| enum { |
| NFNL_BATCH_FAILURE = (1 << 0), |
| NFNL_BATCH_DONE = (1 << 1), |
| NFNL_BATCH_REPLAY = (1 << 2), |
| }; |
| |
| static void nfnetlink_rcv_batch(struct sk_buff *skb, struct nlmsghdr *nlh, |
| u_int16_t subsys_id) |
| { |
| struct sk_buff *oskb = skb; |
| struct net *net = sock_net(skb->sk); |
| const struct nfnetlink_subsystem *ss; |
| const struct nfnl_callback *nc; |
| static LIST_HEAD(err_list); |
| u32 status; |
| int err; |
| |
| if (subsys_id >= NFNL_SUBSYS_COUNT) |
| return netlink_ack(skb, nlh, -EINVAL); |
| replay: |
| status = 0; |
| |
| skb = netlink_skb_clone(oskb, GFP_KERNEL); |
| if (!skb) |
| return netlink_ack(oskb, nlh, -ENOMEM); |
| |
| nfnl_lock(subsys_id); |
| ss = nfnl_dereference_protected(subsys_id); |
| if (!ss) { |
| #ifdef CONFIG_MODULES |
| nfnl_unlock(subsys_id); |
| request_module("nfnetlink-subsys-%d", subsys_id); |
| nfnl_lock(subsys_id); |
| ss = nfnl_dereference_protected(subsys_id); |
| if (!ss) |
| #endif |
| { |
| nfnl_unlock(subsys_id); |
| netlink_ack(oskb, nlh, -EOPNOTSUPP); |
| return kfree_skb(skb); |
| } |
| } |
| |
| if (!ss->commit || !ss->abort) { |
| nfnl_unlock(subsys_id); |
| netlink_ack(oskb, nlh, -EOPNOTSUPP); |
| return kfree_skb(skb); |
| } |
| |
| while (skb->len >= nlmsg_total_size(0)) { |
| int msglen, type; |
| |
| nlh = nlmsg_hdr(skb); |
| err = 0; |
| |
| if (nlh->nlmsg_len < NLMSG_HDRLEN || |
| skb->len < nlh->nlmsg_len || |
| nlmsg_len(nlh) < sizeof(struct nfgenmsg)) { |
| nfnl_err_reset(&err_list); |
| status |= NFNL_BATCH_FAILURE; |
| goto done; |
| } |
| |
| /* Only requests are handled by the kernel */ |
| if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) { |
| err = -EINVAL; |
| goto ack; |
| } |
| |
| type = nlh->nlmsg_type; |
| if (type == NFNL_MSG_BATCH_BEGIN) { |
| /* Malformed: Batch begin twice */ |
| nfnl_err_reset(&err_list); |
| status |= NFNL_BATCH_FAILURE; |
| goto done; |
| } else if (type == NFNL_MSG_BATCH_END) { |
| status |= NFNL_BATCH_DONE; |
| goto done; |
| } else if (type < NLMSG_MIN_TYPE) { |
| err = -EINVAL; |
| goto ack; |
| } |
| |
| /* We only accept a batch with messages for the same |
| * subsystem. |
| */ |
| if (NFNL_SUBSYS_ID(type) != subsys_id) { |
| err = -EINVAL; |
| goto ack; |
| } |
| |
| nc = nfnetlink_find_client(type, ss); |
| if (!nc) { |
| err = -EINVAL; |
| goto ack; |
| } |
| |
| { |
| int min_len = nlmsg_total_size(sizeof(struct nfgenmsg)); |
| u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type); |
| struct nlattr *cda[ss->cb[cb_id].attr_count + 1]; |
| struct nlattr *attr = (void *)nlh + min_len; |
| int attrlen = nlh->nlmsg_len - min_len; |
| |
| err = nla_parse(cda, ss->cb[cb_id].attr_count, |
| attr, attrlen, ss->cb[cb_id].policy); |
| if (err < 0) |
| goto ack; |
| |
| if (nc->call_batch) { |
| err = nc->call_batch(net, net->nfnl, skb, nlh, |
| (const struct nlattr **)cda); |
| } |
| |
| /* The lock was released to autoload some module, we |
| * have to abort and start from scratch using the |
| * original skb. |
| */ |
| if (err == -EAGAIN) { |
| status |= NFNL_BATCH_REPLAY; |
| goto next; |
| } |
| } |
| ack: |
| if (nlh->nlmsg_flags & NLM_F_ACK || err) { |
| /* Errors are delivered once the full batch has been |
| * processed, this avoids that the same error is |
| * reported several times when replaying the batch. |
| */ |
| if (nfnl_err_add(&err_list, nlh, err) < 0) { |
| /* We failed to enqueue an error, reset the |
| * list of errors and send OOM to userspace |
| * pointing to the batch header. |
| */ |
| nfnl_err_reset(&err_list); |
| netlink_ack(oskb, nlmsg_hdr(oskb), -ENOMEM); |
| status |= NFNL_BATCH_FAILURE; |
| goto done; |
| } |
| /* We don't stop processing the batch on errors, thus, |
| * userspace gets all the errors that the batch |
| * triggers. |
| */ |
| if (err) |
| status |= NFNL_BATCH_FAILURE; |
| } |
| next: |
| msglen = NLMSG_ALIGN(nlh->nlmsg_len); |
| if (msglen > skb->len) |
| msglen = skb->len; |
| skb_pull(skb, msglen); |
| } |
| done: |
| if (status & NFNL_BATCH_REPLAY) { |
| ss->abort(net, oskb); |
| nfnl_err_reset(&err_list); |
| nfnl_unlock(subsys_id); |
| kfree_skb(skb); |
| goto replay; |
| } else if (status == NFNL_BATCH_DONE) { |
| ss->commit(net, oskb); |
| } else { |
| ss->abort(net, oskb); |
| } |
| |
| nfnl_err_deliver(&err_list, oskb); |
| nfnl_unlock(subsys_id); |
| kfree_skb(skb); |
| } |
| |
| static void nfnetlink_rcv(struct sk_buff *skb) |
| { |
| struct nlmsghdr *nlh = nlmsg_hdr(skb); |
| u_int16_t res_id; |
| int msglen; |
| |
| if (nlh->nlmsg_len < NLMSG_HDRLEN || |
| skb->len < nlh->nlmsg_len) |
| return; |
| |
| if (!netlink_net_capable(skb, CAP_NET_ADMIN)) { |
| netlink_ack(skb, nlh, -EPERM); |
| return; |
| } |
| |
| if (nlh->nlmsg_type == NFNL_MSG_BATCH_BEGIN) { |
| struct nfgenmsg *nfgenmsg; |
| |
| msglen = NLMSG_ALIGN(nlh->nlmsg_len); |
| if (msglen > skb->len) |
| msglen = skb->len; |
| |
| if (nlh->nlmsg_len < NLMSG_HDRLEN || |
| skb->len < NLMSG_HDRLEN + sizeof(struct nfgenmsg)) |
| return; |
| |
| nfgenmsg = nlmsg_data(nlh); |
| skb_pull(skb, msglen); |
| /* Work around old nft using host byte order */ |
| if (nfgenmsg->res_id == NFNL_SUBSYS_NFTABLES) |
| res_id = NFNL_SUBSYS_NFTABLES; |
| else |
| res_id = ntohs(nfgenmsg->res_id); |
| nfnetlink_rcv_batch(skb, nlh, res_id); |
| } else { |
| netlink_rcv_skb(skb, &nfnetlink_rcv_msg); |
| } |
| } |
| |
| #ifdef CONFIG_MODULES |
| static int nfnetlink_bind(struct net *net, int group) |
| { |
| const struct nfnetlink_subsystem *ss; |
| int type; |
| |
| if (group <= NFNLGRP_NONE || group > NFNLGRP_MAX) |
| return 0; |
| |
| type = nfnl_group2type[group]; |
| |
| rcu_read_lock(); |
| ss = nfnetlink_get_subsys(type << 8); |
| rcu_read_unlock(); |
| if (!ss) |
| request_module("nfnetlink-subsys-%d", type); |
| return 0; |
| } |
| #endif |
| |
| static int __net_init nfnetlink_net_init(struct net *net) |
| { |
| struct sock *nfnl; |
| struct netlink_kernel_cfg cfg = { |
| .groups = NFNLGRP_MAX, |
| .input = nfnetlink_rcv, |
| #ifdef CONFIG_MODULES |
| .bind = nfnetlink_bind, |
| #endif |
| }; |
| |
| nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, &cfg); |
| if (!nfnl) |
| return -ENOMEM; |
| net->nfnl_stash = nfnl; |
| rcu_assign_pointer(net->nfnl, nfnl); |
| return 0; |
| } |
| |
| static void __net_exit nfnetlink_net_exit_batch(struct list_head *net_exit_list) |
| { |
| struct net *net; |
| |
| list_for_each_entry(net, net_exit_list, exit_list) |
| RCU_INIT_POINTER(net->nfnl, NULL); |
| synchronize_net(); |
| list_for_each_entry(net, net_exit_list, exit_list) |
| netlink_kernel_release(net->nfnl_stash); |
| } |
| |
| static struct pernet_operations nfnetlink_net_ops = { |
| .init = nfnetlink_net_init, |
| .exit_batch = nfnetlink_net_exit_batch, |
| }; |
| |
| static int __init nfnetlink_init(void) |
| { |
| int i; |
| |
| for (i = NFNLGRP_NONE + 1; i <= NFNLGRP_MAX; i++) |
| BUG_ON(nfnl_group2type[i] == NFNL_SUBSYS_NONE); |
| |
| for (i=0; i<NFNL_SUBSYS_COUNT; i++) |
| mutex_init(&table[i].mutex); |
| |
| pr_info("Netfilter messages via NETLINK v%s.\n", nfversion); |
| return register_pernet_subsys(&nfnetlink_net_ops); |
| } |
| |
| static void __exit nfnetlink_exit(void) |
| { |
| pr_info("Removing netfilter NETLINK layer.\n"); |
| unregister_pernet_subsys(&nfnetlink_net_ops); |
| } |
| module_init(nfnetlink_init); |
| module_exit(nfnetlink_exit); |