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genetlink.c
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// SPDX-License-Identifier: GPL-2.0
/*
* NETLINK Generic Netlink Family
*
* Authors: Jamal Hadi Salim
* Thomas Graf <[email protected]>
* Johannes Berg <[email protected]>
*/
#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_helpers.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);
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;
/* We need the last attribute with non-zero ID therefore a 2-entry array */
static struct nla_policy genl_policy_reject_all[] = {
{ .type = NLA_REJECT },
{ .type = NLA_REJECT },
};
static int genl_ctrl_event(int event, const struct genl_family *family,
const struct genl_multicast_group *grp,
int grp_id);
static void
genl_op_fill_in_reject_policy(const struct genl_family *family,
struct genl_ops *op)
{
BUILD_BUG_ON(ARRAY_SIZE(genl_policy_reject_all) - 1 != 1);
if (op->policy || op->cmd < family->resv_start_op)
return;
op->policy = genl_policy_reject_all;
op->maxattr = 1;
}
static void
genl_op_fill_in_reject_policy_split(const struct genl_family *family,
struct genl_split_ops *op)
{
if (op->policy)
return;
op->policy = genl_policy_reject_all;
op->maxattr = 1;
}
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;
}
struct genl_op_iter {
const struct genl_family *family;
struct genl_split_ops doit;
struct genl_split_ops dumpit;
int cmd_idx;
int entry_idx;
u32 cmd;
u8 flags;
};
static void genl_op_from_full(const struct genl_family *family,
unsigned int i, struct genl_ops *op)
{
*op = family->ops[i];
if (!op->maxattr)
op->maxattr = family->maxattr;
if (!op->policy)
op->policy = family->policy;
genl_op_fill_in_reject_policy(family, op);
}
static int genl_get_cmd_full(u32 cmd, const struct genl_family *family,
struct genl_ops *op)
{
int i;
for (i = 0; i < family->n_ops; i++)
if (family->ops[i].cmd == cmd) {
genl_op_from_full(family, i, op);
return 0;
}
return -ENOENT;
}
static void genl_op_from_small(const struct genl_family *family,
unsigned int i, struct genl_ops *op)
{
memset(op, 0, sizeof(*op));
op->doit = family->small_ops[i].doit;
op->dumpit = family->small_ops[i].dumpit;
op->cmd = family->small_ops[i].cmd;
op->internal_flags = family->small_ops[i].internal_flags;
op->flags = family->small_ops[i].flags;
op->validate = family->small_ops[i].validate;
op->maxattr = family->maxattr;
op->policy = family->policy;
genl_op_fill_in_reject_policy(family, op);
}
static int genl_get_cmd_small(u32 cmd, const struct genl_family *family,
struct genl_ops *op)
{
int i;
for (i = 0; i < family->n_small_ops; i++)
if (family->small_ops[i].cmd == cmd) {
genl_op_from_small(family, i, op);
return 0;
}
return -ENOENT;
}
static void genl_op_from_split(struct genl_op_iter *iter)
{
const struct genl_family *family = iter->family;
int i, cnt = 0;
i = iter->entry_idx - family->n_ops - family->n_small_ops;
if (family->split_ops[i + cnt].flags & GENL_CMD_CAP_DO) {
iter->doit = family->split_ops[i + cnt];
genl_op_fill_in_reject_policy_split(family, &iter->doit);
cnt++;
} else {
memset(&iter->doit, 0, sizeof(iter->doit));
}
if (i + cnt < family->n_split_ops &&
family->split_ops[i + cnt].flags & GENL_CMD_CAP_DUMP) {
iter->dumpit = family->split_ops[i + cnt];
genl_op_fill_in_reject_policy_split(family, &iter->dumpit);
cnt++;
} else {
memset(&iter->dumpit, 0, sizeof(iter->dumpit));
}
WARN_ON(!cnt);
iter->entry_idx += cnt;
}
static int
genl_get_cmd_split(u32 cmd, u8 flag, const struct genl_family *family,
struct genl_split_ops *op)
{
int i;
for (i = 0; i < family->n_split_ops; i++)
if (family->split_ops[i].cmd == cmd &&
family->split_ops[i].flags & flag) {
*op = family->split_ops[i];
return 0;
}
return -ENOENT;
}
static int
genl_cmd_full_to_split(struct genl_split_ops *op,
const struct genl_family *family,
const struct genl_ops *full, u8 flags)
{
if ((flags & GENL_CMD_CAP_DO && !full->doit) ||
(flags & GENL_CMD_CAP_DUMP && !full->dumpit)) {
memset(op, 0, sizeof(*op));
return -ENOENT;
}
if (flags & GENL_CMD_CAP_DUMP) {
op->start = full->start;
op->dumpit = full->dumpit;
op->done = full->done;
} else {
op->pre_doit = family->pre_doit;
op->doit = full->doit;
op->post_doit = family->post_doit;
}
if (flags & GENL_CMD_CAP_DUMP &&
full->validate & GENL_DONT_VALIDATE_DUMP) {
op->policy = NULL;
op->maxattr = 0;
} else {
op->policy = full->policy;
op->maxattr = full->maxattr;
}
op->cmd = full->cmd;
op->internal_flags = full->internal_flags;
op->flags = full->flags;
op->validate = full->validate;
/* Make sure flags include the GENL_CMD_CAP_DO / GENL_CMD_CAP_DUMP */
op->flags |= flags;
return 0;
}
/* Must make sure that op is initialized to 0 on failure */
static int
genl_get_cmd(u32 cmd, u8 flags, const struct genl_family *family,
struct genl_split_ops *op)
{
struct genl_ops full;
int err;
err = genl_get_cmd_full(cmd, family, &full);
if (err == -ENOENT)
err = genl_get_cmd_small(cmd, family, &full);
/* Found one of legacy forms */
if (err == 0)
return genl_cmd_full_to_split(op, family, &full, flags);
err = genl_get_cmd_split(cmd, flags, family, op);
if (err)
memset(op, 0, sizeof(*op));
return err;
}
/* For policy dumping only, get ops of both do and dump.
* Fail if both are missing, genl_get_cmd() will zero-init in case of failure.
*/
static int
genl_get_cmd_both(u32 cmd, const struct genl_family *family,
struct genl_split_ops *doit, struct genl_split_ops *dumpit)
{
int err1, err2;
err1 = genl_get_cmd(cmd, GENL_CMD_CAP_DO, family, doit);
err2 = genl_get_cmd(cmd, GENL_CMD_CAP_DUMP, family, dumpit);
return err1 && err2 ? -ENOENT : 0;
}
static bool
genl_op_iter_init(const struct genl_family *family, struct genl_op_iter *iter)
{
iter->family = family;
iter->cmd_idx = 0;
iter->entry_idx = 0;
iter->flags = 0;
return iter->family->n_ops +
iter->family->n_small_ops +
iter->family->n_split_ops;
}
static bool genl_op_iter_next(struct genl_op_iter *iter)
{
const struct genl_family *family = iter->family;
bool legacy_op = true;
struct genl_ops op;
if (iter->entry_idx < family->n_ops) {
genl_op_from_full(family, iter->entry_idx, &op);
} else if (iter->entry_idx < family->n_ops + family->n_small_ops) {
genl_op_from_small(family, iter->entry_idx - family->n_ops,
&op);
} else if (iter->entry_idx <
family->n_ops + family->n_small_ops + family->n_split_ops) {
legacy_op = false;
/* updates entry_idx */
genl_op_from_split(iter);
} else {
return false;
}
iter->cmd_idx++;
if (legacy_op) {
iter->entry_idx++;
genl_cmd_full_to_split(&iter->doit, family,
&op, GENL_CMD_CAP_DO);
genl_cmd_full_to_split(&iter->dumpit, family,
&op, GENL_CMD_CAP_DUMP);
}
iter->cmd = iter->doit.cmd | iter->dumpit.cmd;
iter->flags = iter->doit.flags | iter->dumpit.flags;
return true;
}
static void
genl_op_iter_copy(struct genl_op_iter *dst, struct genl_op_iter *src)
{
*dst = *src;
}
static unsigned int genl_op_iter_idx(struct genl_op_iter *iter)
{
return iter->cmd_idx;
}
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(!string_is_terminated(grp->name, GENL_NAMSIZ)))
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 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 bool genl_split_op_check(const struct genl_split_ops *op)
{
if (WARN_ON(hweight8(op->flags & (GENL_CMD_CAP_DO |
GENL_CMD_CAP_DUMP)) != 1))
return true;
return false;
}
static int genl_validate_ops(const struct genl_family *family)
{
struct genl_op_iter i, j;
unsigned int s;
if (WARN_ON(family->n_ops && !family->ops) ||
WARN_ON(family->n_small_ops && !family->small_ops) ||
WARN_ON(family->n_split_ops && !family->split_ops))
return -EINVAL;
for (genl_op_iter_init(family, &i); genl_op_iter_next(&i); ) {
if (!(i.flags & (GENL_CMD_CAP_DO | GENL_CMD_CAP_DUMP)))
return -EINVAL;
if (WARN_ON(i.cmd >= family->resv_start_op &&
(i.doit.validate || i.dumpit.validate)))
return -EINVAL;
genl_op_iter_copy(&j, &i);
while (genl_op_iter_next(&j)) {
if (i.cmd == j.cmd)
return -EINVAL;
}
}
if (family->n_split_ops) {
if (genl_split_op_check(&family->split_ops[0]))
return -EINVAL;
}
for (s = 1; s < family->n_split_ops; s++) {
const struct genl_split_ops *a, *b;
a = &family->split_ops[s - 1];
b = &family->split_ops[s];
if (genl_split_op_check(b))
return -EINVAL;
/* Check sort order */
if (a->cmd < b->cmd)
continue;
if (a->internal_flags != b->internal_flags ||
((a->flags ^ b->flags) & ~(GENL_CMD_CAP_DO |
GENL_CMD_CAP_DUMP))) {
WARN_ON(1);
return -EINVAL;
}
if ((a->flags & GENL_CMD_CAP_DO) &&
(b->flags & GENL_CMD_CAP_DUMP))
continue;
WARN_ON(1);
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_split_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 (!ops->maxattr)
return NULL;
attrbuf = kmalloc_array(ops->maxattr + 1,
sizeof(struct nlattr *), GFP_KERNEL);
if (!attrbuf)
return ERR_PTR(-ENOMEM);
err = __nlmsg_parse(nlh, hdrlen, attrbuf, ops->maxattr, ops->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_split_ops *ops;
int hdrlen;
};
static int genl_start(struct netlink_callback *cb)
{
struct genl_start_context *ctx = cb->data;
const struct genl_split_ops *ops;
struct genl_dumpit_info *info;
struct nlattr **attrs = NULL;
int rc = 0;
ops = ctx->ops;
if (!(ops->validate & GENL_DONT_VALIDATE_DUMP) &&
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);
info = genl_dumpit_info_alloc();
if (!info) {
genl_family_rcv_msg_attrs_free(attrs);
return -ENOMEM;
}
info->family = ctx->family;
info->op = *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_split_ops *ops = &genl_dumpit_info(cb)->op;
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_split_ops *ops = &info->op;
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_split_ops *ops = &info->op;
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_split_ops *ops,
int hdrlen, struct net *net)
{
struct genl_start_context ctx;
int err;
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,
.extack = extack,
};
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,
.extack = extack,
};
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_split_ops *ops,
int hdrlen, struct net *net)
{
struct nlattr **attrbuf;
struct genl_info info;
int err;
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 (ops->pre_doit) {
err = ops->pre_doit(ops, skb, &info);
if (err)
goto out;
}
err = ops->doit(skb, &info);
if (ops->post_doit)
ops->post_doit(ops, skb, &info);
out:
genl_family_rcv_msg_attrs_free(attrbuf);
return err;
}
static int genl_header_check(const struct genl_family *family,
struct nlmsghdr *nlh, struct genlmsghdr *hdr,
struct netlink_ext_ack *extack)
{
u16 flags;
/* Only for commands added after we started validating */
if (hdr->cmd < family->resv_start_op)
return 0;
if (hdr->reserved) {
NL_SET_ERR_MSG(extack, "genlmsghdr.reserved field is not 0");
return -EINVAL;
}
/* Old netlink flags have pretty loose semantics, allow only the flags
* consumed by the core where we can enforce the meaning.
*/
flags = nlh->nlmsg_flags;
if ((flags & NLM_F_DUMP) == NLM_F_DUMP) /* DUMP is 2 bits */