| // 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; |
| } |
| |
| family->id = idr_alloc_cyclic(&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); |
| 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(); |
| |
| 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 struct genl_dumpit_info *genl_dumpit_info_alloc(void) |
| { |
| return kmalloc(sizeof(struct genl_dumpit_info), GFP_KERNEL); |
| } |
| |
| static void genl_dumpit_info_free(const struct genl_dumpit_info *info) |
| { |
| kfree(info); |
| } |
| |
| static struct nlattr ** |
| genl_family_rcv_msg_attrs_parse(const struct genl_family *family, |
| struct nlmsghdr *nlh, |
| struct netlink_ext_ack *extack, |
| const struct genl_ops *ops, |
| int hdrlen, |
| enum genl_validate_flags no_strict_flag) |
| { |
| enum netlink_validation validate = ops->validate & no_strict_flag ? |
| NL_VALIDATE_LIBERAL : |
| NL_VALIDATE_STRICT; |
| struct nlattr **attrbuf; |
| int err; |
| |
| if (!family->maxattr) |
| return NULL; |
| |
| attrbuf = kmalloc_array(family->maxattr + 1, |
| sizeof(struct nlattr *), GFP_KERNEL); |
| if (!attrbuf) |
| return ERR_PTR(-ENOMEM); |
| |
| err = __nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr, |
| family->policy, validate, extack); |
| if (err) { |
| kfree(attrbuf); |
| return ERR_PTR(err); |
| } |
| return attrbuf; |
| } |
| |
| static void genl_family_rcv_msg_attrs_free(struct nlattr **attrbuf) |
| { |
| kfree(attrbuf); |
| } |
| |
| struct genl_start_context { |
| const struct genl_family *family; |
| struct nlmsghdr *nlh; |
| struct netlink_ext_ack *extack; |
| const struct genl_ops *ops; |
| int hdrlen; |
| }; |
| |
| static int genl_start(struct netlink_callback *cb) |
| { |
| struct genl_start_context *ctx = cb->data; |
| const struct genl_ops *ops = ctx->ops; |
| struct genl_dumpit_info *info; |
| struct nlattr **attrs = NULL; |
| int rc = 0; |
| |
| if (ops->validate & GENL_DONT_VALIDATE_DUMP) |
| goto no_attrs; |
| |
| if (ctx->nlh->nlmsg_len < nlmsg_msg_size(ctx->hdrlen)) |
| return -EINVAL; |
| |
| attrs = genl_family_rcv_msg_attrs_parse(ctx->family, ctx->nlh, ctx->extack, |
| ops, ctx->hdrlen, |
| GENL_DONT_VALIDATE_DUMP_STRICT); |
| if (IS_ERR(attrs)) |
| return PTR_ERR(attrs); |
| |
| no_attrs: |
| info = genl_dumpit_info_alloc(); |
| if (!info) { |
| genl_family_rcv_msg_attrs_free(attrs); |
| return -ENOMEM; |
| } |
| info->family = ctx->family; |
| info->ops = ops; |
| info->attrs = attrs; |
| |
| cb->data = info; |
| if (ops->start) { |
| if (!ctx->family->parallel_ops) |
| genl_lock(); |
| rc = ops->start(cb); |
| if (!ctx->family->parallel_ops) |
| genl_unlock(); |
| } |
| |
| if (rc) { |
| genl_family_rcv_msg_attrs_free(info->attrs); |
| genl_dumpit_info_free(info); |
| cb->data = NULL; |
| } |
| return rc; |
| } |
| |
| static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb) |
| { |
| const struct genl_ops *ops = genl_dumpit_info(cb)->ops; |
| int rc; |
| |
| genl_lock(); |
| rc = ops->dumpit(skb, cb); |
| genl_unlock(); |
| return rc; |
| } |
| |
| static int genl_lock_done(struct netlink_callback *cb) |
| { |
| const struct genl_dumpit_info *info = genl_dumpit_info(cb); |
| const struct genl_ops *ops = info->ops; |
| int rc = 0; |
| |
| if (ops->done) { |
| genl_lock(); |
| rc = ops->done(cb); |
| genl_unlock(); |
| } |
| genl_family_rcv_msg_attrs_free(info->attrs); |
| genl_dumpit_info_free(info); |
| return rc; |
| } |
| |
| static int genl_parallel_done(struct netlink_callback *cb) |
| { |
| const struct genl_dumpit_info *info = genl_dumpit_info(cb); |
| const struct genl_ops *ops = info->ops; |
| int rc = 0; |
| |
| if (ops->done) |
| rc = ops->done(cb); |
| genl_family_rcv_msg_attrs_free(info->attrs); |
| genl_dumpit_info_free(info); |
| return rc; |
| } |
| |
| static int genl_family_rcv_msg_dumpit(const struct genl_family *family, |
| struct sk_buff *skb, |
| struct nlmsghdr *nlh, |
| struct netlink_ext_ack *extack, |
| const struct genl_ops *ops, |
| int hdrlen, struct net *net) |
| { |
| struct genl_start_context ctx; |
| int err; |
| |
| if (!ops->dumpit) |
| return -EOPNOTSUPP; |
| |
| ctx.family = family; |
| ctx.nlh = nlh; |
| ctx.extack = extack; |
| ctx.ops = ops; |
| ctx.hdrlen = hdrlen; |
| |
| if (!family->parallel_ops) { |
| struct netlink_dump_control c = { |
| .module = family->module, |
| .data = &ctx, |
| .start = genl_start, |
| .dump = genl_lock_dumpit, |
| .done = genl_lock_done, |
| }; |
| |
| genl_unlock(); |
| err = __netlink_dump_start(net->genl_sock, skb, nlh, &c); |
| genl_lock(); |
| } else { |
| struct netlink_dump_control c = { |
| .module = family->module, |
| .data = &ctx, |
| .start = genl_start, |
| .dump = ops->dumpit, |
| .done = genl_parallel_done, |
| }; |
| |
| err = __netlink_dump_start(net->genl_sock, skb, nlh, &c); |
| } |
| |
| return err; |
| } |
| |
| static int genl_family_rcv_msg_doit(const struct genl_family *family, |
| struct sk_buff *skb, |
| struct nlmsghdr *nlh, |
| struct netlink_ext_ack *extack, |
| const struct genl_ops *ops, |
| int hdrlen, struct net *net) |
| { |
| struct nlattr **attrbuf; |
| struct genl_info info; |
| int err; |
| |
| if (!ops->doit) |
| return -EOPNOTSUPP; |
| |
| attrbuf = genl_family_rcv_msg_attrs_parse(family, nlh, extack, |
| ops, hdrlen, |
| GENL_DONT_VALIDATE_STRICT); |
| if (IS_ERR(attrbuf)) |
| return PTR_ERR(attrbuf); |
| |
| 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: |
| genl_family_rcv_msg_attrs_free(attrbuf); |
| |
| return err; |
| } |
| |
| 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 genlmsghdr *hdr = nlmsg_data(nlh); |
| int hdrlen; |
| |
| /* 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) |
| return genl_family_rcv_msg_dumpit(family, skb, nlh, extack, |
| ops, hdrlen, net); |
| else |
| return genl_family_rcv_msg_doit(family, skb, nlh, extack, |
| ops, hdrlen, net); |
| } |
| |
| 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_noflag(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 (family->policy) |
| op_flags |= GENL_CMD_CAP_HASPOL; |
| |
| nest = nla_nest_start_noflag(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_noflag(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_noflag(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_noflag(skb, CTRL_ATTR_MCAST_GROUPS); |
| if (nla_grps == NULL) |
| goto nla_put_failure; |
| |
| nest = nla_nest_start_noflag(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 int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb) |
| { |
| const struct genl_family *rt; |
| unsigned int fam_id = cb->args[0]; |
| int err; |
| |
| if (!fam_id) { |
| struct nlattr *tb[CTRL_ATTR_MAX + 1]; |
| |
| err = genlmsg_parse(cb->nlh, &genl_ctrl, tb, |
| genl_ctrl.maxattr, |
| genl_ctrl.policy, cb->extack); |
| if (err) |
| return err; |
| |
| if (!tb[CTRL_ATTR_FAMILY_ID] && !tb[CTRL_ATTR_FAMILY_NAME]) |
| return -EINVAL; |
| |
| if (tb[CTRL_ATTR_FAMILY_ID]) { |
| fam_id = nla_get_u16(tb[CTRL_ATTR_FAMILY_ID]); |
| } else { |
| rt = genl_family_find_byname( |
| nla_data(tb[CTRL_ATTR_FAMILY_NAME])); |
| if (!rt) |
| return -ENOENT; |
| fam_id = rt->id; |
| } |
| } |
| |
| rt = genl_family_find_byid(fam_id); |
| if (!rt) |
| return -ENOENT; |
| |
| if (!rt->policy) |
| return -ENODATA; |
| |
| err = netlink_policy_dump_start(rt->policy, rt->maxattr, &cb->args[1]); |
| if (err) |
| return err; |
| |
| while (netlink_policy_dump_loop(cb->args[1])) { |
| void *hdr; |
| struct nlattr *nest; |
| |
| hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, |
| cb->nlh->nlmsg_seq, &genl_ctrl, |
| NLM_F_MULTI, CTRL_CMD_GETPOLICY); |
| if (!hdr) |
| goto nla_put_failure; |
| |
| if (nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, rt->id)) |
| goto nla_put_failure; |
| |
| nest = nla_nest_start(skb, CTRL_ATTR_POLICY); |
| if (!nest) |
| goto nla_put_failure; |
| |
| if (netlink_policy_dump_write(skb, cb->args[1])) |
| goto nla_put_failure; |
| |
| nla_nest_end(skb, nest); |
| |
| genlmsg_end(skb, hdr); |
| continue; |
| |
| nla_put_failure: |
| genlmsg_cancel(skb, hdr); |
| break; |
| } |
| |
| cb->args[0] = fam_id; |
| return skb->len; |
| } |
| |
| static int ctrl_dumppolicy_done(struct netlink_callback *cb) |
| { |
| netlink_policy_dump_free(cb->args[1]); |
| return 0; |
| } |
| |
| static const struct genl_ops genl_ctrl_ops[] = { |
| { |
| .cmd = CTRL_CMD_GETFAMILY, |
| .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, |
| .doit = ctrl_getfamily, |
| .dumpit = ctrl_dumpfamily, |
| }, |
| { |
| .cmd = CTRL_CMD_GETPOLICY, |
| .dumpit = ctrl_dumppolicy, |
| .done = ctrl_dumppolicy_done, |
| }, |
| }; |
| |
| 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, |
| .policy = ctrl_policy, |
| .netnsok = true, |
| }; |
| |
| static int __net_init genl_pernet_init(struct net *net) |
| { |
| struct netlink_kernel_cfg cfg = { |
| .input = genl_rcv, |
| .flags = NL_CFG_F_NONROOT_RECV, |
| }; |
| |
| /* 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); |
| } |
| |
| core_initcall(genl_init); |
| |
| 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); |