v4.19.13 snapshot.
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
new file mode 100644
index 0000000..25eeb6d
--- /dev/null
+++ b/net/netlink/genetlink.c
@@ -0,0 +1,1144 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * NETLINK Generic Netlink Family
+ *
+ * Authors: Jamal Hadi Salim
+ * Thomas Graf <tgraf@suug.ch>
+ * Johannes Berg <johannes@sipsolutions.net>
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/string.h>
+#include <linux/skbuff.h>
+#include <linux/mutex.h>
+#include <linux/bitmap.h>
+#include <linux/rwsem.h>
+#include <linux/idr.h>
+#include <net/sock.h>
+#include <net/genetlink.h>
+
+static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
+static DECLARE_RWSEM(cb_lock);
+
+atomic_t genl_sk_destructing_cnt = ATOMIC_INIT(0);
+DECLARE_WAIT_QUEUE_HEAD(genl_sk_destructing_waitq);
+
+void genl_lock(void)
+{
+ mutex_lock(&genl_mutex);
+}
+EXPORT_SYMBOL(genl_lock);
+
+void genl_unlock(void)
+{
+ mutex_unlock(&genl_mutex);
+}
+EXPORT_SYMBOL(genl_unlock);
+
+#ifdef CONFIG_LOCKDEP
+bool lockdep_genl_is_held(void)
+{
+ return lockdep_is_held(&genl_mutex);
+}
+EXPORT_SYMBOL(lockdep_genl_is_held);
+#endif
+
+static void genl_lock_all(void)
+{
+ down_write(&cb_lock);
+ genl_lock();
+}
+
+static void genl_unlock_all(void)
+{
+ genl_unlock();
+ up_write(&cb_lock);
+}
+
+static DEFINE_IDR(genl_fam_idr);
+
+/*
+ * Bitmap of multicast groups that are currently in use.
+ *
+ * To avoid an allocation at boot of just one unsigned long,
+ * declare it global instead.
+ * Bit 0 is marked as already used since group 0 is invalid.
+ * Bit 1 is marked as already used since the drop-monitor code
+ * abuses the API and thinks it can statically use group 1.
+ * That group will typically conflict with other groups that
+ * any proper users use.
+ * Bit 16 is marked as used since it's used for generic netlink
+ * and the code no longer marks pre-reserved IDs as used.
+ * Bit 17 is marked as already used since the VFS quota code
+ * also abused this API and relied on family == group ID, we
+ * cater to that by giving it a static family and group ID.
+ * Bit 18 is marked as already used since the PMCRAID driver
+ * did the same thing as the VFS quota code (maybe copied?)
+ */
+static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) |
+ BIT(GENL_ID_VFS_DQUOT) |
+ BIT(GENL_ID_PMCRAID);
+static unsigned long *mc_groups = &mc_group_start;
+static unsigned long mc_groups_longs = 1;
+
+static int genl_ctrl_event(int event, const struct genl_family *family,
+ const struct genl_multicast_group *grp,
+ int grp_id);
+
+static const struct genl_family *genl_family_find_byid(unsigned int id)
+{
+ return idr_find(&genl_fam_idr, id);
+}
+
+static const struct genl_family *genl_family_find_byname(char *name)
+{
+ const struct genl_family *family;
+ unsigned int id;
+
+ idr_for_each_entry(&genl_fam_idr, family, id)
+ if (strcmp(family->name, name) == 0)
+ return family;
+
+ return NULL;
+}
+
+static const struct genl_ops *genl_get_cmd(u8 cmd,
+ const struct genl_family *family)
+{
+ int i;
+
+ for (i = 0; i < family->n_ops; i++)
+ if (family->ops[i].cmd == cmd)
+ return &family->ops[i];
+
+ return NULL;
+}
+
+static int genl_allocate_reserve_groups(int n_groups, int *first_id)
+{
+ unsigned long *new_groups;
+ int start = 0;
+ int i;
+ int id;
+ bool fits;
+
+ do {
+ if (start == 0)
+ id = find_first_zero_bit(mc_groups,
+ mc_groups_longs *
+ BITS_PER_LONG);
+ else
+ id = find_next_zero_bit(mc_groups,
+ mc_groups_longs * BITS_PER_LONG,
+ start);
+
+ fits = true;
+ for (i = id;
+ i < min_t(int, id + n_groups,
+ mc_groups_longs * BITS_PER_LONG);
+ i++) {
+ if (test_bit(i, mc_groups)) {
+ start = i;
+ fits = false;
+ break;
+ }
+ }
+
+ if (id + n_groups > mc_groups_longs * BITS_PER_LONG) {
+ unsigned long new_longs = mc_groups_longs +
+ BITS_TO_LONGS(n_groups);
+ size_t nlen = new_longs * sizeof(unsigned long);
+
+ if (mc_groups == &mc_group_start) {
+ new_groups = kzalloc(nlen, GFP_KERNEL);
+ if (!new_groups)
+ return -ENOMEM;
+ mc_groups = new_groups;
+ *mc_groups = mc_group_start;
+ } else {
+ new_groups = krealloc(mc_groups, nlen,
+ GFP_KERNEL);
+ if (!new_groups)
+ return -ENOMEM;
+ mc_groups = new_groups;
+ for (i = 0; i < BITS_TO_LONGS(n_groups); i++)
+ mc_groups[mc_groups_longs + i] = 0;
+ }
+ mc_groups_longs = new_longs;
+ }
+ } while (!fits);
+
+ for (i = id; i < id + n_groups; i++)
+ set_bit(i, mc_groups);
+ *first_id = id;
+ return 0;
+}
+
+static struct genl_family genl_ctrl;
+
+static int genl_validate_assign_mc_groups(struct genl_family *family)
+{
+ int first_id;
+ int n_groups = family->n_mcgrps;
+ int err = 0, i;
+ bool groups_allocated = false;
+
+ if (!n_groups)
+ return 0;
+
+ for (i = 0; i < n_groups; i++) {
+ const struct genl_multicast_group *grp = &family->mcgrps[i];
+
+ if (WARN_ON(grp->name[0] == '\0'))
+ return -EINVAL;
+ if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL))
+ return -EINVAL;
+ }
+
+ /* special-case our own group and hacks */
+ if (family == &genl_ctrl) {
+ first_id = GENL_ID_CTRL;
+ BUG_ON(n_groups != 1);
+ } else if (strcmp(family->name, "NET_DM") == 0) {
+ first_id = 1;
+ BUG_ON(n_groups != 1);
+ } else if (family->id == GENL_ID_VFS_DQUOT) {
+ first_id = GENL_ID_VFS_DQUOT;
+ BUG_ON(n_groups != 1);
+ } else if (family->id == GENL_ID_PMCRAID) {
+ first_id = GENL_ID_PMCRAID;
+ BUG_ON(n_groups != 1);
+ } else {
+ groups_allocated = true;
+ err = genl_allocate_reserve_groups(n_groups, &first_id);
+ if (err)
+ return err;
+ }
+
+ family->mcgrp_offset = first_id;
+
+ /* if still initializing, can't and don't need to to realloc bitmaps */
+ if (!init_net.genl_sock)
+ return 0;
+
+ if (family->netnsok) {
+ struct net *net;
+
+ netlink_table_grab();
+ rcu_read_lock();
+ for_each_net_rcu(net) {
+ err = __netlink_change_ngroups(net->genl_sock,
+ mc_groups_longs * BITS_PER_LONG);
+ if (err) {
+ /*
+ * No need to roll back, can only fail if
+ * memory allocation fails and then the
+ * number of _possible_ groups has been
+ * increased on some sockets which is ok.
+ */
+ break;
+ }
+ }
+ rcu_read_unlock();
+ netlink_table_ungrab();
+ } else {
+ err = netlink_change_ngroups(init_net.genl_sock,
+ mc_groups_longs * BITS_PER_LONG);
+ }
+
+ if (groups_allocated && err) {
+ for (i = 0; i < family->n_mcgrps; i++)
+ clear_bit(family->mcgrp_offset + i, mc_groups);
+ }
+
+ return err;
+}
+
+static void genl_unregister_mc_groups(const struct genl_family *family)
+{
+ struct net *net;
+ int i;
+
+ netlink_table_grab();
+ rcu_read_lock();
+ for_each_net_rcu(net) {
+ for (i = 0; i < family->n_mcgrps; i++)
+ __netlink_clear_multicast_users(
+ net->genl_sock, family->mcgrp_offset + i);
+ }
+ rcu_read_unlock();
+ netlink_table_ungrab();
+
+ for (i = 0; i < family->n_mcgrps; i++) {
+ int grp_id = family->mcgrp_offset + i;
+
+ if (grp_id != 1)
+ clear_bit(grp_id, mc_groups);
+ genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family,
+ &family->mcgrps[i], grp_id);
+ }
+}
+
+static int genl_validate_ops(const struct genl_family *family)
+{
+ const struct genl_ops *ops = family->ops;
+ unsigned int n_ops = family->n_ops;
+ int i, j;
+
+ if (WARN_ON(n_ops && !ops))
+ return -EINVAL;
+
+ if (!n_ops)
+ return 0;
+
+ for (i = 0; i < n_ops; i++) {
+ if (ops[i].dumpit == NULL && ops[i].doit == NULL)
+ return -EINVAL;
+ for (j = i + 1; j < n_ops; j++)
+ if (ops[i].cmd == ops[j].cmd)
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/**
+ * genl_register_family - register a generic netlink family
+ * @family: generic netlink family
+ *
+ * Registers the specified family after validating it first. Only one
+ * family may be registered with the same family name or identifier.
+ *
+ * The family's ops, multicast groups and module pointer must already
+ * be assigned.
+ *
+ * Return 0 on success or a negative error code.
+ */
+int genl_register_family(struct genl_family *family)
+{
+ int err, i;
+ int start = GENL_START_ALLOC, end = GENL_MAX_ID;
+
+ err = genl_validate_ops(family);
+ if (err)
+ return err;
+
+ genl_lock_all();
+
+ if (genl_family_find_byname(family->name)) {
+ err = -EEXIST;
+ goto errout_locked;
+ }
+
+ /*
+ * Sadly, a few cases need to be special-cased
+ * due to them having previously abused the API
+ * and having used their family ID also as their
+ * multicast group ID, so we use reserved IDs
+ * for both to be sure we can do that mapping.
+ */
+ if (family == &genl_ctrl) {
+ /* and this needs to be special for initial family lookups */
+ start = end = GENL_ID_CTRL;
+ } else if (strcmp(family->name, "pmcraid") == 0) {
+ start = end = GENL_ID_PMCRAID;
+ } else if (strcmp(family->name, "VFS_DQUOT") == 0) {
+ start = end = GENL_ID_VFS_DQUOT;
+ }
+
+ if (family->maxattr && !family->parallel_ops) {
+ family->attrbuf = kmalloc_array(family->maxattr + 1,
+ sizeof(struct nlattr *),
+ GFP_KERNEL);
+ if (family->attrbuf == NULL) {
+ err = -ENOMEM;
+ goto errout_locked;
+ }
+ } else
+ family->attrbuf = NULL;
+
+ family->id = idr_alloc(&genl_fam_idr, family,
+ start, end + 1, GFP_KERNEL);
+ if (family->id < 0) {
+ err = family->id;
+ goto errout_locked;
+ }
+
+ err = genl_validate_assign_mc_groups(family);
+ if (err)
+ goto errout_remove;
+
+ genl_unlock_all();
+
+ /* send all events */
+ genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL, 0);
+ for (i = 0; i < family->n_mcgrps; i++)
+ genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family,
+ &family->mcgrps[i], family->mcgrp_offset + i);
+
+ return 0;
+
+errout_remove:
+ idr_remove(&genl_fam_idr, family->id);
+ kfree(family->attrbuf);
+errout_locked:
+ genl_unlock_all();
+ return err;
+}
+EXPORT_SYMBOL(genl_register_family);
+
+/**
+ * genl_unregister_family - unregister generic netlink family
+ * @family: generic netlink family
+ *
+ * Unregisters the specified family.
+ *
+ * Returns 0 on success or a negative error code.
+ */
+int genl_unregister_family(const struct genl_family *family)
+{
+ genl_lock_all();
+
+ if (!genl_family_find_byid(family->id)) {
+ genl_unlock_all();
+ return -ENOENT;
+ }
+
+ genl_unregister_mc_groups(family);
+
+ idr_remove(&genl_fam_idr, family->id);
+
+ up_write(&cb_lock);
+ wait_event(genl_sk_destructing_waitq,
+ atomic_read(&genl_sk_destructing_cnt) == 0);
+ genl_unlock();
+
+ kfree(family->attrbuf);
+
+ genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0);
+
+ return 0;
+}
+EXPORT_SYMBOL(genl_unregister_family);
+
+/**
+ * genlmsg_put - Add generic netlink header to netlink message
+ * @skb: socket buffer holding the message
+ * @portid: netlink portid the message is addressed to
+ * @seq: sequence number (usually the one of the sender)
+ * @family: generic netlink family
+ * @flags: netlink message flags
+ * @cmd: generic netlink command
+ *
+ * Returns pointer to user specific header
+ */
+void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
+ const struct genl_family *family, int flags, u8 cmd)
+{
+ struct nlmsghdr *nlh;
+ struct genlmsghdr *hdr;
+
+ nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN +
+ family->hdrsize, flags);
+ if (nlh == NULL)
+ return NULL;
+
+ hdr = nlmsg_data(nlh);
+ hdr->cmd = cmd;
+ hdr->version = family->version;
+ hdr->reserved = 0;
+
+ return (char *) hdr + GENL_HDRLEN;
+}
+EXPORT_SYMBOL(genlmsg_put);
+
+static int genl_lock_start(struct netlink_callback *cb)
+{
+ /* our ops are always const - netlink API doesn't propagate that */
+ const struct genl_ops *ops = cb->data;
+ int rc = 0;
+
+ if (ops->start) {
+ genl_lock();
+ rc = ops->start(cb);
+ genl_unlock();
+ }
+ return rc;
+}
+
+static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
+{
+ /* our ops are always const - netlink API doesn't propagate that */
+ const struct genl_ops *ops = cb->data;
+ int rc;
+
+ genl_lock();
+ rc = ops->dumpit(skb, cb);
+ genl_unlock();
+ return rc;
+}
+
+static int genl_lock_done(struct netlink_callback *cb)
+{
+ /* our ops are always const - netlink API doesn't propagate that */
+ const struct genl_ops *ops = cb->data;
+ int rc = 0;
+
+ if (ops->done) {
+ genl_lock();
+ rc = ops->done(cb);
+ genl_unlock();
+ }
+ return rc;
+}
+
+static int genl_family_rcv_msg(const struct genl_family *family,
+ struct sk_buff *skb,
+ struct nlmsghdr *nlh,
+ struct netlink_ext_ack *extack)
+{
+ const struct genl_ops *ops;
+ struct net *net = sock_net(skb->sk);
+ struct genl_info info;
+ struct genlmsghdr *hdr = nlmsg_data(nlh);
+ struct nlattr **attrbuf;
+ int hdrlen, err;
+
+ /* this family doesn't exist in this netns */
+ if (!family->netnsok && !net_eq(net, &init_net))
+ return -ENOENT;
+
+ hdrlen = GENL_HDRLEN + family->hdrsize;
+ if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
+ return -EINVAL;
+
+ ops = genl_get_cmd(hdr->cmd, family);
+ if (ops == NULL)
+ return -EOPNOTSUPP;
+
+ if ((ops->flags & GENL_ADMIN_PERM) &&
+ !netlink_capable(skb, CAP_NET_ADMIN))
+ return -EPERM;
+
+ if ((ops->flags & GENL_UNS_ADMIN_PERM) &&
+ !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
+ return -EPERM;
+
+ if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) {
+ int rc;
+
+ if (ops->dumpit == NULL)
+ return -EOPNOTSUPP;
+
+ if (!family->parallel_ops) {
+ struct netlink_dump_control c = {
+ .module = family->module,
+ /* we have const, but the netlink API doesn't */
+ .data = (void *)ops,
+ .start = genl_lock_start,
+ .dump = genl_lock_dumpit,
+ .done = genl_lock_done,
+ };
+
+ genl_unlock();
+ rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
+ genl_lock();
+
+ } else {
+ struct netlink_dump_control c = {
+ .module = family->module,
+ .start = ops->start,
+ .dump = ops->dumpit,
+ .done = ops->done,
+ };
+
+ rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
+ }
+
+ return rc;
+ }
+
+ if (ops->doit == NULL)
+ return -EOPNOTSUPP;
+
+ if (family->maxattr && family->parallel_ops) {
+ attrbuf = kmalloc_array(family->maxattr + 1,
+ sizeof(struct nlattr *),
+ GFP_KERNEL);
+ if (attrbuf == NULL)
+ return -ENOMEM;
+ } else
+ attrbuf = family->attrbuf;
+
+ if (attrbuf) {
+ err = nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr,
+ ops->policy, extack);
+ if (err < 0)
+ goto out;
+ }
+
+ info.snd_seq = nlh->nlmsg_seq;
+ info.snd_portid = NETLINK_CB(skb).portid;
+ info.nlhdr = nlh;
+ info.genlhdr = nlmsg_data(nlh);
+ info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
+ info.attrs = attrbuf;
+ info.extack = extack;
+ genl_info_net_set(&info, net);
+ memset(&info.user_ptr, 0, sizeof(info.user_ptr));
+
+ if (family->pre_doit) {
+ err = family->pre_doit(ops, skb, &info);
+ if (err)
+ goto out;
+ }
+
+ err = ops->doit(skb, &info);
+
+ if (family->post_doit)
+ family->post_doit(ops, skb, &info);
+
+out:
+ if (family->parallel_ops)
+ kfree(attrbuf);
+
+ return err;
+}
+
+static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
+ struct netlink_ext_ack *extack)
+{
+ const struct genl_family *family;
+ int err;
+
+ family = genl_family_find_byid(nlh->nlmsg_type);
+ if (family == NULL)
+ return -ENOENT;
+
+ if (!family->parallel_ops)
+ genl_lock();
+
+ err = genl_family_rcv_msg(family, skb, nlh, extack);
+
+ if (!family->parallel_ops)
+ genl_unlock();
+
+ return err;
+}
+
+static void genl_rcv(struct sk_buff *skb)
+{
+ down_read(&cb_lock);
+ netlink_rcv_skb(skb, &genl_rcv_msg);
+ up_read(&cb_lock);
+}
+
+/**************************************************************************
+ * Controller
+ **************************************************************************/
+
+static struct genl_family genl_ctrl;
+
+static int ctrl_fill_info(const struct genl_family *family, u32 portid, u32 seq,
+ u32 flags, struct sk_buff *skb, u8 cmd)
+{
+ void *hdr;
+
+ hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
+ if (hdr == NULL)
+ return -1;
+
+ if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
+ nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) ||
+ nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) ||
+ nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) ||
+ nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
+ goto nla_put_failure;
+
+ if (family->n_ops) {
+ struct nlattr *nla_ops;
+ int i;
+
+ nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
+ if (nla_ops == NULL)
+ goto nla_put_failure;
+
+ for (i = 0; i < family->n_ops; i++) {
+ struct nlattr *nest;
+ const struct genl_ops *ops = &family->ops[i];
+ u32 op_flags = ops->flags;
+
+ if (ops->dumpit)
+ op_flags |= GENL_CMD_CAP_DUMP;
+ if (ops->doit)
+ op_flags |= GENL_CMD_CAP_DO;
+ if (ops->policy)
+ op_flags |= GENL_CMD_CAP_HASPOL;
+
+ nest = nla_nest_start(skb, i + 1);
+ if (nest == NULL)
+ goto nla_put_failure;
+
+ if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) ||
+ nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags))
+ goto nla_put_failure;
+
+ nla_nest_end(skb, nest);
+ }
+
+ nla_nest_end(skb, nla_ops);
+ }
+
+ if (family->n_mcgrps) {
+ struct nlattr *nla_grps;
+ int i;
+
+ nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
+ if (nla_grps == NULL)
+ goto nla_put_failure;
+
+ for (i = 0; i < family->n_mcgrps; i++) {
+ struct nlattr *nest;
+ const struct genl_multicast_group *grp;
+
+ grp = &family->mcgrps[i];
+
+ nest = nla_nest_start(skb, i + 1);
+ if (nest == NULL)
+ goto nla_put_failure;
+
+ if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID,
+ family->mcgrp_offset + i) ||
+ nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
+ grp->name))
+ goto nla_put_failure;
+
+ nla_nest_end(skb, nest);
+ }
+ nla_nest_end(skb, nla_grps);
+ }
+
+ genlmsg_end(skb, hdr);
+ return 0;
+
+nla_put_failure:
+ genlmsg_cancel(skb, hdr);
+ return -EMSGSIZE;
+}
+
+static int ctrl_fill_mcgrp_info(const struct genl_family *family,
+ const struct genl_multicast_group *grp,
+ int grp_id, u32 portid, u32 seq, u32 flags,
+ struct sk_buff *skb, u8 cmd)
+{
+ void *hdr;
+ struct nlattr *nla_grps;
+ struct nlattr *nest;
+
+ hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
+ if (hdr == NULL)
+ return -1;
+
+ if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
+ nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id))
+ goto nla_put_failure;
+
+ nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
+ if (nla_grps == NULL)
+ goto nla_put_failure;
+
+ nest = nla_nest_start(skb, 1);
+ if (nest == NULL)
+ goto nla_put_failure;
+
+ if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) ||
+ nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
+ grp->name))
+ goto nla_put_failure;
+
+ nla_nest_end(skb, nest);
+ nla_nest_end(skb, nla_grps);
+
+ genlmsg_end(skb, hdr);
+ return 0;
+
+nla_put_failure:
+ genlmsg_cancel(skb, hdr);
+ return -EMSGSIZE;
+}
+
+static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
+{
+ int n = 0;
+ struct genl_family *rt;
+ struct net *net = sock_net(skb->sk);
+ int fams_to_skip = cb->args[0];
+ unsigned int id;
+
+ idr_for_each_entry(&genl_fam_idr, rt, id) {
+ if (!rt->netnsok && !net_eq(net, &init_net))
+ continue;
+
+ if (n++ < fams_to_skip)
+ continue;
+
+ if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid,
+ cb->nlh->nlmsg_seq, NLM_F_MULTI,
+ skb, CTRL_CMD_NEWFAMILY) < 0) {
+ n--;
+ break;
+ }
+ }
+
+ cb->args[0] = n;
+ return skb->len;
+}
+
+static struct sk_buff *ctrl_build_family_msg(const struct genl_family *family,
+ u32 portid, int seq, u8 cmd)
+{
+ struct sk_buff *skb;
+ int err;
+
+ skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+ if (skb == NULL)
+ return ERR_PTR(-ENOBUFS);
+
+ err = ctrl_fill_info(family, portid, seq, 0, skb, cmd);
+ if (err < 0) {
+ nlmsg_free(skb);
+ return ERR_PTR(err);
+ }
+
+ return skb;
+}
+
+static struct sk_buff *
+ctrl_build_mcgrp_msg(const struct genl_family *family,
+ const struct genl_multicast_group *grp,
+ int grp_id, u32 portid, int seq, u8 cmd)
+{
+ struct sk_buff *skb;
+ int err;
+
+ skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+ if (skb == NULL)
+ return ERR_PTR(-ENOBUFS);
+
+ err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid,
+ seq, 0, skb, cmd);
+ if (err < 0) {
+ nlmsg_free(skb);
+ return ERR_PTR(err);
+ }
+
+ return skb;
+}
+
+static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
+ [CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
+ [CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
+ .len = GENL_NAMSIZ - 1 },
+};
+
+static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
+{
+ struct sk_buff *msg;
+ const struct genl_family *res = NULL;
+ int err = -EINVAL;
+
+ if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
+ u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
+ res = genl_family_find_byid(id);
+ err = -ENOENT;
+ }
+
+ if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
+ char *name;
+
+ name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
+ res = genl_family_find_byname(name);
+#ifdef CONFIG_MODULES
+ if (res == NULL) {
+ genl_unlock();
+ up_read(&cb_lock);
+ request_module("net-pf-%d-proto-%d-family-%s",
+ PF_NETLINK, NETLINK_GENERIC, name);
+ down_read(&cb_lock);
+ genl_lock();
+ res = genl_family_find_byname(name);
+ }
+#endif
+ err = -ENOENT;
+ }
+
+ if (res == NULL)
+ return err;
+
+ if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
+ /* family doesn't exist here */
+ return -ENOENT;
+ }
+
+ msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq,
+ CTRL_CMD_NEWFAMILY);
+ if (IS_ERR(msg))
+ return PTR_ERR(msg);
+
+ return genlmsg_reply(msg, info);
+}
+
+static int genl_ctrl_event(int event, const struct genl_family *family,
+ const struct genl_multicast_group *grp,
+ int grp_id)
+{
+ struct sk_buff *msg;
+
+ /* genl is still initialising */
+ if (!init_net.genl_sock)
+ return 0;
+
+ switch (event) {
+ case CTRL_CMD_NEWFAMILY:
+ case CTRL_CMD_DELFAMILY:
+ WARN_ON(grp);
+ msg = ctrl_build_family_msg(family, 0, 0, event);
+ break;
+ case CTRL_CMD_NEWMCAST_GRP:
+ case CTRL_CMD_DELMCAST_GRP:
+ BUG_ON(!grp);
+ msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event);
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ if (IS_ERR(msg))
+ return PTR_ERR(msg);
+
+ if (!family->netnsok) {
+ genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0,
+ 0, GFP_KERNEL);
+ } else {
+ rcu_read_lock();
+ genlmsg_multicast_allns(&genl_ctrl, msg, 0,
+ 0, GFP_ATOMIC);
+ rcu_read_unlock();
+ }
+
+ return 0;
+}
+
+static const struct genl_ops genl_ctrl_ops[] = {
+ {
+ .cmd = CTRL_CMD_GETFAMILY,
+ .doit = ctrl_getfamily,
+ .dumpit = ctrl_dumpfamily,
+ .policy = ctrl_policy,
+ },
+};
+
+static const struct genl_multicast_group genl_ctrl_groups[] = {
+ { .name = "notify", },
+};
+
+static struct genl_family genl_ctrl __ro_after_init = {
+ .module = THIS_MODULE,
+ .ops = genl_ctrl_ops,
+ .n_ops = ARRAY_SIZE(genl_ctrl_ops),
+ .mcgrps = genl_ctrl_groups,
+ .n_mcgrps = ARRAY_SIZE(genl_ctrl_groups),
+ .id = GENL_ID_CTRL,
+ .name = "nlctrl",
+ .version = 0x2,
+ .maxattr = CTRL_ATTR_MAX,
+ .netnsok = true,
+};
+
+static int genl_bind(struct net *net, int group)
+{
+ struct genl_family *f;
+ int err = -ENOENT;
+ unsigned int id;
+
+ down_read(&cb_lock);
+
+ idr_for_each_entry(&genl_fam_idr, f, id) {
+ if (group >= f->mcgrp_offset &&
+ group < f->mcgrp_offset + f->n_mcgrps) {
+ int fam_grp = group - f->mcgrp_offset;
+
+ if (!f->netnsok && net != &init_net)
+ err = -ENOENT;
+ else if (f->mcast_bind)
+ err = f->mcast_bind(net, fam_grp);
+ else
+ err = 0;
+ break;
+ }
+ }
+ up_read(&cb_lock);
+
+ return err;
+}
+
+static void genl_unbind(struct net *net, int group)
+{
+ struct genl_family *f;
+ unsigned int id;
+
+ down_read(&cb_lock);
+
+ idr_for_each_entry(&genl_fam_idr, f, id) {
+ if (group >= f->mcgrp_offset &&
+ group < f->mcgrp_offset + f->n_mcgrps) {
+ int fam_grp = group - f->mcgrp_offset;
+
+ if (f->mcast_unbind)
+ f->mcast_unbind(net, fam_grp);
+ break;
+ }
+ }
+ up_read(&cb_lock);
+}
+
+static int __net_init genl_pernet_init(struct net *net)
+{
+ struct netlink_kernel_cfg cfg = {
+ .input = genl_rcv,
+ .flags = NL_CFG_F_NONROOT_RECV,
+ .bind = genl_bind,
+ .unbind = genl_unbind,
+ };
+
+ /* we'll bump the group number right afterwards */
+ net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg);
+
+ if (!net->genl_sock && net_eq(net, &init_net))
+ panic("GENL: Cannot initialize generic netlink\n");
+
+ if (!net->genl_sock)
+ return -ENOMEM;
+
+ return 0;
+}
+
+static void __net_exit genl_pernet_exit(struct net *net)
+{
+ netlink_kernel_release(net->genl_sock);
+ net->genl_sock = NULL;
+}
+
+static struct pernet_operations genl_pernet_ops = {
+ .init = genl_pernet_init,
+ .exit = genl_pernet_exit,
+};
+
+static int __init genl_init(void)
+{
+ int err;
+
+ err = genl_register_family(&genl_ctrl);
+ if (err < 0)
+ goto problem;
+
+ err = register_pernet_subsys(&genl_pernet_ops);
+ if (err)
+ goto problem;
+
+ return 0;
+
+problem:
+ panic("GENL: Cannot register controller: %d\n", err);
+}
+
+subsys_initcall(genl_init);
+
+/**
+ * genl_family_attrbuf - return family's attrbuf
+ * @family: the family
+ *
+ * Return the family's attrbuf, while validating that it's
+ * actually valid to access it.
+ *
+ * You cannot use this function with a family that has parallel_ops
+ * and you can only use it within (pre/post) doit/dumpit callbacks.
+ */
+struct nlattr **genl_family_attrbuf(const struct genl_family *family)
+{
+ if (!WARN_ON(family->parallel_ops))
+ lockdep_assert_held(&genl_mutex);
+
+ return family->attrbuf;
+}
+EXPORT_SYMBOL(genl_family_attrbuf);
+
+static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
+ gfp_t flags)
+{
+ struct sk_buff *tmp;
+ struct net *net, *prev = NULL;
+ bool delivered = false;
+ int err;
+
+ for_each_net_rcu(net) {
+ if (prev) {
+ tmp = skb_clone(skb, flags);
+ if (!tmp) {
+ err = -ENOMEM;
+ goto error;
+ }
+ err = nlmsg_multicast(prev->genl_sock, tmp,
+ portid, group, flags);
+ if (!err)
+ delivered = true;
+ else if (err != -ESRCH)
+ goto error;
+ }
+
+ prev = net;
+ }
+
+ err = nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
+ if (!err)
+ delivered = true;
+ else if (err != -ESRCH)
+ return err;
+ return delivered ? 0 : -ESRCH;
+ error:
+ kfree_skb(skb);
+ return err;
+}
+
+int genlmsg_multicast_allns(const struct genl_family *family,
+ struct sk_buff *skb, u32 portid,
+ unsigned int group, gfp_t flags)
+{
+ if (WARN_ON_ONCE(group >= family->n_mcgrps))
+ return -EINVAL;
+ group = family->mcgrp_offset + group;
+ return genlmsg_mcast(skb, portid, group, flags);
+}
+EXPORT_SYMBOL(genlmsg_multicast_allns);
+
+void genl_notify(const struct genl_family *family, struct sk_buff *skb,
+ struct genl_info *info, u32 group, gfp_t flags)
+{
+ struct net *net = genl_info_net(info);
+ struct sock *sk = net->genl_sock;
+ int report = 0;
+
+ if (info->nlhdr)
+ report = nlmsg_report(info->nlhdr);
+
+ if (WARN_ON_ONCE(group >= family->n_mcgrps))
+ return;
+ group = family->mcgrp_offset + group;
+ nlmsg_notify(sk, skb, info->snd_portid, group, report, flags);
+}
+EXPORT_SYMBOL(genl_notify);