Release 4.11 net/netlink/genetlink.c

/*
 * 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);
}
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2
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EXPORT_SYMBOL(genl_lock);



void genl_unlock(void)
{
	mutex_unlock(&genl_mutex);
}
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2
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EXPORT_SYMBOL(genl_unlock);

#ifdef CONFIG_LOCKDEP


bool lockdep_genl_is_held(void)
{
	return lockdep_is_held(&genl_mutex);
}
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Yaowei Bai
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EXPORT_SYMBOL(lockdep_genl_is_held);
#endif



static void genl_lock_all(void)
{
	down_write(&cb_lock);
	genl_lock();
}

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static void genl_unlock_all(void)
{
	genl_unlock();
	up_write(&cb_lock);
}

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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);
}

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Thomas Graf
16
72.73%
1
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6
27.27%
1
50.00%
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22
100.00%
2
100.00%



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;
}

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Thomas Graf
39
78.00%
1
50.00%
Johannes Berg
11
22.00%
1
50.00%
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50
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2
100.00%



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;
}

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Johannes Berg
31
50.82%
3
75.00%
Thomas Graf
30
49.18%
1
25.00%
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61
100.00%
4
100.00%



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;
}

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Johannes Berg
253
91.01%
5
50.00%
Thomas Graf
16
5.76%
1
10.00%
Jamal Hadi Salim
4
1.44%
1
10.00%
Brian Haley
2
0.72%
1
10.00%
Matti Vaittinen
2
0.72%
1
10.00%
David S. Miller
1
0.36%
1
10.00%
Total
278
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10
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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;
}

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Johannes Berg
331
95.11%
6
54.55%
Thomas Graf
11
3.16%
3
27.27%
Jamal Hadi Salim
4
1.15%
1
9.09%
Geert Uytterhoeven
2
0.57%
1
9.09%
Total
348
100.00%
11
100.00%



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);
	}
}

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Johannes Berg
111
90.98%
7
77.78%
Thomas Graf
11
9.02%
2
22.22%
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122
100.00%
9
100.00%



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;
}

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133
99.25%
5
83.33%
Cheng Renquan
1
0.75%
1
16.67%
Total
134
100.00%
6
100.00%

/**
 * 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((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;
}
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Johannes Berg
159
50.16%
6
50.00%
Thomas Graf
123
38.80%
1
8.33%
Wei Yongjun
10
3.15%
1
8.33%
Krishna Kumar
9
2.84%
1
8.33%
Pravin B Shelar
8
2.52%
1
8.33%
Américo Wang
7
2.21%
1
8.33%
Jamal Hadi Salim
1
0.32%
1
8.33%
Total
317
100.00%
12
100.00%


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;
}
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Johannes Berg
46
50.55%
4
50.00%
Thomas Graf
41
45.05%
1
12.50%
Pavel Emelyanov
2
2.20%
1
12.50%
Pravin B Shelar
1
1.10%
1
12.50%
pravin shelar
1
1.10%
1
12.50%
Total
91
100.00%
8
100.00%


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;
}
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Denys Vlasenko
104
97.20%
1
33.33%
Eric W. Biedermann
2
1.87%
1
33.33%
Johannes Berg
1
0.93%
1
33.33%
Total
107
100.00%
3
100.00%


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;
}

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Tom Herbert
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100.00%
1
100.00%
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53
100.00%
1
100.00%



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;
}

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Pravin B Shelar
48
96.00%
1
50.00%
Johannes Berg
2
4.00%
1
50.00%
Total
50
100.00%
2
100.00%



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;
}

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Pravin B Shelar
51
96.23%
1
50.00%
Johannes Berg
2
3.77%
1
50.00%
Total
53
100.00%
2
100.00%



static int genl_family_rcv_msg(const struct genl_family *family,
			       struct sk_buff *skb,
			       struct nlmsghdr *nlh)
{
	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((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);
		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;
	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;
}

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Commits
CommitProp
Thomas Graf
221
38.10%
2
11.11%
Pravin B Shelar
167
28.79%
3
16.67%
Johannes Berg
114
19.66%
4
22.22%
Tycho Andersen
26
4.48%
1
5.56%
Pablo Neira Ayuso
25
4.31%
2
11.11%
Tom Herbert
12
2.07%
1
5.56%
Wei Yongjun
8
1.38%
1
5.56%
Eric W. Biedermann
5
0.86%
2
11.11%
Darrel Goeddel
1
0.17%
1
5.56%
Eric Paris
1
0.17%
1
5.56%
Total
580
100.00%
18
100.00%



static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
{
	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);

	if (!family->parallel_ops)
		genl_unlock();

	return err;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Pravin B Shelar
73
93.59%
1
25.00%
Johannes Berg
3
3.85%
2
50.00%
Thomas Graf
2
2.56%
1
25.00%
Total
78
100.00%
4
100.00%



static void genl_rcv(struct sk_buff *skb)
{
	down_read(&cb_lock);
	netlink_rcv_skb(skb, &genl_rcv_msg);
	up_read(&cb_lock);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Thomas Graf
15
48.39%
1
25.00%
Pravin B Shelar
10
32.26%
1
25.00%
Denis V. Lunev
6
19.35%
2
50.00%
Total
31
100.00%
4
100.00%

/**************************************************************************
 * 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->