1 files changed, 702 insertions, 204 deletions

diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 1afca2a6c2ac..978c129c6095 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -13,7 +13,7 @@
 #include <linux/errno.h>
 #include <linux/types.h>
 #include <linux/socket.h>
-#include <linux/string.h>
+#include <linux/string_helpers.h>
 #include <linux/skbuff.h>
 #include <linux/mutex.h>
 #include <linux/bitmap.h>
@@ -22,6 +22,8 @@
 #include <net/sock.h>
 #include <net/genetlink.h>
 
+#include "genetlink.h"
+
 static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
 static DECLARE_RWSEM(cb_lock);
 
@@ -52,6 +54,18 @@ static void genl_unlock_all(void)
 	up_write(&cb_lock);
 }
 
+static void genl_op_lock(const struct genl_family *family)
+{
+	if (!family->parallel_ops)
+		genl_lock();
+}
+
+static void genl_op_unlock(const struct genl_family *family)
+{
+	if (!family->parallel_ops)
+		genl_unlock();
+}
+
 static DEFINE_IDR(genl_fam_idr);
 
 /*
@@ -78,10 +92,40 @@ static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) |
 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);
@@ -99,10 +143,15 @@ static const struct genl_family *genl_family_find_byname(char *name)
 	return NULL;
 }
 
-static int genl_get_cmd_cnt(const struct genl_family *family)
-{
-	return family->n_ops + family->n_small_ops;
-}
+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)
@@ -113,6 +162,8 @@ static void genl_op_from_full(const struct genl_family *family,
 		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,
@@ -142,6 +193,8 @@ static void genl_op_from_small(const struct genl_family *family,
 
 	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,
@@ -158,24 +211,188 @@ static int genl_get_cmd_small(u32 cmd, const struct genl_family *family,
 	return -ENOENT;
 }
 
-static int genl_get_cmd(u32 cmd, const struct genl_family *family,
-			struct genl_ops *op)
+static void genl_op_from_split(struct genl_op_iter *iter)
 {
-	if (!genl_get_cmd_full(cmd, family, op))
-		return 0;
-	return genl_get_cmd_small(cmd, family, op);
+	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 &&
+	    (!cnt || family->split_ops[i + cnt].cmd == iter->doit.cmd)) {
+		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 void genl_get_cmd_by_index(unsigned int i,
-				  const struct genl_family *family,
-				  struct genl_ops *op)
+static int
+genl_get_cmd_split(u32 cmd, u8 flag, const struct genl_family *family,
+		   struct genl_split_ops *op)
 {
-	if (i < family->n_ops)
-		genl_op_from_full(family, i, op);
-	else if (i < family->n_ops + family->n_small_ops)
-		genl_op_from_small(family, i - family->n_ops, op);
-	else
-		WARN_ON_ONCE(1);
+	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)
@@ -255,7 +472,7 @@ static int genl_validate_assign_mc_groups(struct genl_family *family)
 
 		if (WARN_ON(grp->name[0] == '\0'))
 			return -EINVAL;
-		if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL))
+		if (WARN_ON(!string_is_terminated(grp->name, GENL_NAMSIZ)))
 			return -EINVAL;
 	}
 
@@ -343,32 +560,211 @@ static void genl_unregister_mc_groups(const struct genl_family *family)
 	}
 }
 
+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)
 {
-	int i, j;
+	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_small_ops && !family->small_ops) ||
+	    WARN_ON(family->n_split_ops && !family->split_ops))
 		return -EINVAL;
 
-	for (i = 0; i < genl_get_cmd_cnt(family); i++) {
-		struct genl_ops op;
+	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;
 
-		genl_get_cmd_by_index(i, family, &op);
-		if (op.dumpit == NULL && op.doit == NULL)
+		if (WARN_ON(i.cmd >= family->resv_start_op &&
+			    (i.doit.validate || i.dumpit.validate)))
 			return -EINVAL;
-		for (j = i + 1; j < genl_get_cmd_cnt(family); j++) {
-			struct genl_ops op2;
 
-			genl_get_cmd_by_index(j, family, &op2);
-			if (op.cmd == op2.cmd)
+		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;
+		} else if (a->cmd > b->cmd) {
+			WARN_ON(1);
+			return -EINVAL;
+		}
+
+		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;
+}
+
+static void *genl_sk_priv_alloc(struct genl_family *family)
+{
+	void *priv;
+
+	priv = kzalloc(family->sock_priv_size, GFP_KERNEL);
+	if (!priv)
+		return ERR_PTR(-ENOMEM);
+
+	if (family->sock_priv_init)
+		family->sock_priv_init(priv);
+
+	return priv;
+}
+
+static void genl_sk_priv_free(const struct genl_family *family, void *priv)
+{
+	if (family->sock_priv_destroy)
+		family->sock_priv_destroy(priv);
+	kfree(priv);
+}
+
+static int genl_sk_privs_alloc(struct genl_family *family)
+{
+	if (!family->sock_priv_size)
+		return 0;
+
+	family->sock_privs = kzalloc(sizeof(*family->sock_privs), GFP_KERNEL);
+	if (!family->sock_privs)
+		return -ENOMEM;
+	xa_init(family->sock_privs);
 	return 0;
 }
 
+static void genl_sk_privs_free(const struct genl_family *family)
+{
+	unsigned long id;
+	void *priv;
+
+	if (!family->sock_priv_size)
+		return;
+
+	xa_for_each(family->sock_privs, id, priv)
+		genl_sk_priv_free(family, priv);
+
+	xa_destroy(family->sock_privs);
+	kfree(family->sock_privs);
+}
+
+static void genl_sk_priv_free_by_sock(struct genl_family *family,
+				      struct sock *sk)
+{
+	void *priv;
+
+	if (!family->sock_priv_size)
+		return;
+	priv = xa_erase(family->sock_privs, (unsigned long) sk);
+	if (!priv)
+		return;
+	genl_sk_priv_free(family, priv);
+}
+
+static void genl_release(struct sock *sk, unsigned long *groups)
+{
+	struct genl_family *family;
+	unsigned int id;
+
+	down_read(&cb_lock);
+
+	idr_for_each_entry(&genl_fam_idr, family, id)
+		genl_sk_priv_free_by_sock(family, sk);
+
+	up_read(&cb_lock);
+}
+
+/**
+ * __genl_sk_priv_get - Get family private pointer for socket, if exists
+ *
+ * @family: family
+ * @sk: socket
+ *
+ * Lookup a private memory for a Generic netlink family and specified socket.
+ *
+ * Caller should make sure this is called in RCU read locked section.
+ *
+ * Return: valid pointer on success, otherwise negative error value
+ * encoded by ERR_PTR(), NULL in case priv does not exist.
+ */
+void *__genl_sk_priv_get(struct genl_family *family, struct sock *sk)
+{
+	if (WARN_ON_ONCE(!family->sock_privs))
+		return ERR_PTR(-EINVAL);
+	return xa_load(family->sock_privs, (unsigned long) sk);
+}
+
+/**
+ * genl_sk_priv_get - Get family private pointer for socket
+ *
+ * @family: family
+ * @sk: socket
+ *
+ * Lookup a private memory for a Generic netlink family and specified socket.
+ * Allocate the private memory in case it was not already done.
+ *
+ * Return: valid pointer on success, otherwise negative error value
+ * encoded by ERR_PTR().
+ */
+void *genl_sk_priv_get(struct genl_family *family, struct sock *sk)
+{
+	void *priv, *old_priv;
+
+	priv = __genl_sk_priv_get(family, sk);
+	if (priv)
+		return priv;
+
+	/* priv for the family does not exist so far, create it. */
+
+	priv = genl_sk_priv_alloc(family);
+	if (IS_ERR(priv))
+		return ERR_CAST(priv);
+
+	old_priv = xa_cmpxchg(family->sock_privs, (unsigned long) sk, NULL,
+			      priv, GFP_KERNEL);
+	if (old_priv) {
+		genl_sk_priv_free(family, priv);
+		if (xa_is_err(old_priv))
+			return ERR_PTR(xa_err(old_priv));
+		/* Race happened, priv for the socket was already inserted. */
+		return old_priv;
+	}
+	return priv;
+}
+
 /**
  * genl_register_family - register a generic netlink family
  * @family: generic netlink family
@@ -397,6 +793,10 @@ int genl_register_family(struct genl_family *family)
 		goto errout_locked;
 	}
 
+	err = genl_sk_privs_alloc(family);
+	if (err)
+		goto errout_locked;
+
 	/*
 	 * Sadly, a few cases need to be special-cased
 	 * due to them having previously abused the API
@@ -417,7 +817,7 @@ int genl_register_family(struct genl_family *family)
 				      start, end + 1, GFP_KERNEL);
 	if (family->id < 0) {
 		err = family->id;
-		goto errout_locked;
+		goto errout_sk_privs_free;
 	}
 
 	err = genl_validate_assign_mc_groups(family);
@@ -436,6 +836,8 @@ int genl_register_family(struct genl_family *family)
 
 errout_remove:
 	idr_remove(&genl_fam_idr, family->id);
+errout_sk_privs_free:
+	genl_sk_privs_free(family);
 errout_locked:
 	genl_unlock_all();
 	return err;
@@ -466,6 +868,9 @@ int genl_unregister_family(const struct genl_family *family)
 	up_write(&cb_lock);
 	wait_event(genl_sk_destructing_waitq,
 		   atomic_read(&genl_sk_destructing_cnt) == 0);
+
+	genl_sk_privs_free(family);
+
 	genl_unlock();
 
 	genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0);
@@ -519,7 +924,7 @@ 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,
+				const struct genl_split_ops *ops,
 				int hdrlen,
 				enum genl_validate_flags no_strict_flag)
 {
@@ -555,22 +960,21 @@ struct genl_start_context {
 	const struct genl_family *family;
 	struct nlmsghdr *nlh;
 	struct netlink_ext_ack *extack;
-	const struct genl_ops *ops;
+	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_ops *ops = ctx->ops;
+	const struct genl_split_ops *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))
+	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,
@@ -579,70 +983,68 @@ static int genl_start(struct netlink_callback *cb)
 	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->op = *ops;
-	info->attrs = attrs;
+	info->info.family	= ctx->family;
+	info->info.snd_seq	= cb->nlh->nlmsg_seq;
+	info->info.snd_portid	= NETLINK_CB(cb->skb).portid;
+	info->info.nlhdr	= cb->nlh;
+	info->info.genlhdr	= nlmsg_data(cb->nlh);
+	info->info.attrs	= attrs;
+	genl_info_net_set(&info->info, sock_net(cb->skb->sk));
+	info->info.extack	= cb->extack;
+	memset(&info->info.ctx, 0, sizeof(info->info.ctx));
 
 	cb->data = info;
 	if (ops->start) {
-		if (!ctx->family->parallel_ops)
-			genl_lock();
+		genl_op_lock(ctx->family);
 		rc = ops->start(cb);
-		if (!ctx->family->parallel_ops)
-			genl_unlock();
+		genl_op_unlock(ctx->family);
 	}
 
 	if (rc) {
-		genl_family_rcv_msg_attrs_free(info->attrs);
+		genl_family_rcv_msg_attrs_free(info->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)
+static int genl_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 {
-	const struct genl_ops *ops = &genl_dumpit_info(cb)->op;
+	struct genl_dumpit_info *dump_info = cb->data;
+	const struct genl_split_ops *ops = &dump_info->op;
+	struct genl_info *info = &dump_info->info;
 	int rc;
 
-	genl_lock();
+	info->extack = cb->extack;
+
+	genl_op_lock(info->family);
 	rc = ops->dumpit(skb, cb);
-	genl_unlock();
+	genl_op_unlock(info->family);
 	return rc;
 }
 
-static int genl_lock_done(struct netlink_callback *cb)
+static int genl_done(struct netlink_callback *cb)
 {
-	const struct genl_dumpit_info *info = genl_dumpit_info(cb);
-	const struct genl_ops *ops = &info->op;
+	struct genl_dumpit_info *dump_info = cb->data;
+	const struct genl_split_ops *ops = &dump_info->op;
+	struct genl_info *info = &dump_info->info;
 	int rc = 0;
 
+	info->extack = cb->extack;
+
 	if (ops->done) {
-		genl_lock();
+		genl_op_lock(info->family);
 		rc = ops->done(cb);
-		genl_unlock();
+		genl_op_unlock(info->family);
 	}
 	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->op;
-	int rc = 0;
-
-	if (ops->done)
-		rc = ops->done(cb);
-	genl_family_rcv_msg_attrs_free(info->attrs);
-	genl_dumpit_info_free(info);
+	genl_dumpit_info_free(dump_info);
 	return rc;
 }
 
@@ -650,44 +1052,29 @@ 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,
+				      const struct genl_split_ops *ops,
 				      int hdrlen, struct net *net)
 {
 	struct genl_start_context ctx;
+	struct netlink_dump_control c = {
+		.module = family->module,
+		.data = &ctx,
+		.start = genl_start,
+		.dump = genl_dumpit,
+		.done = genl_done,
+		.extack = extack,
+	};
 	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);
-	}
+	genl_op_unlock(family);
+	err = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
+	genl_op_lock(family);
 
 	return err;
 }
@@ -696,16 +1083,13 @@ 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,
+				    const struct genl_split_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);
@@ -714,24 +1098,24 @@ static int genl_family_rcv_msg_doit(const struct genl_family *family,
 
 	info.snd_seq = nlh->nlmsg_seq;
 	info.snd_portid = NETLINK_CB(skb).portid;
+	info.family = family;
 	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));
+	memset(&info.ctx, 0, sizeof(info.ctx));
 
-	if (family->pre_doit) {
-		err = family->pre_doit(ops, skb, &info);
+	if (ops->pre_doit) {
+		err = ops->pre_doit(ops, skb, &info);
 		if (err)
 			goto out;
 	}
 
 	err = ops->doit(skb, &info);
 
-	if (family->post_doit)
-		family->post_doit(ops, skb, &info);
+	if (ops->post_doit)
+		ops->post_doit(ops, skb, &info);
 
 out:
 	genl_family_rcv_msg_attrs_free(attrbuf);
@@ -739,6 +1123,36 @@ out:
 	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 */
+		flags &= ~NLM_F_DUMP;
+	if (flags & ~(NLM_F_REQUEST | NLM_F_ACK | NLM_F_ECHO)) {
+		NL_SET_ERR_MSG(extack,
+			       "ambiguous or reserved bits set in nlmsg_flags");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static int genl_family_rcv_msg(const struct genl_family *family,
 			       struct sk_buff *skb,
 			       struct nlmsghdr *nlh,
@@ -746,8 +1160,9 @@ static int genl_family_rcv_msg(const struct genl_family *family,
 {
 	struct net *net = sock_net(skb->sk);
 	struct genlmsghdr *hdr = nlmsg_data(nlh);
-	struct genl_ops op;
+	struct genl_split_ops op;
 	int hdrlen;
+	u8 flags;
 
 	/* this family doesn't exist in this netns */
 	if (!family->netnsok && !net_eq(net, &init_net))
@@ -757,7 +1172,12 @@ static int genl_family_rcv_msg(const struct genl_family *family,
 	if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
 		return -EINVAL;
 
-	if (genl_get_cmd(hdr->cmd, family, &op))
+	if (genl_header_check(family, nlh, hdr, extack))
+		return -EINVAL;
+
+	flags = (nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP ?
+		GENL_CMD_CAP_DUMP : GENL_CMD_CAP_DO;
+	if (genl_get_cmd(hdr->cmd, flags, family, &op))
 		return -EOPNOTSUPP;
 
 	if ((op.flags & GENL_ADMIN_PERM) &&
@@ -768,7 +1188,7 @@ static int genl_family_rcv_msg(const struct genl_family *family,
 	    !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
 		return -EPERM;
 
-	if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP)
+	if (flags & GENL_CMD_CAP_DUMP)
 		return genl_family_rcv_msg_dumpit(family, skb, nlh, extack,
 						  &op, hdrlen, net);
 	else
@@ -786,13 +1206,9 @@ static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
 	if (family == NULL)
 		return -ENOENT;
 
-	if (!family->parallel_ops)
-		genl_lock();
-
+	genl_op_lock(family);
 	err = genl_family_rcv_msg(family, skb, nlh, extack);
-
-	if (!family->parallel_ops)
-		genl_unlock();
+	genl_op_unlock(family);
 
 	return err;
 }
@@ -813,11 +1229,12 @@ 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)
 {
+	struct genl_op_iter i;
 	void *hdr;
 
 	hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
 	if (hdr == NULL)
-		return -1;
+		return -EMSGSIZE;
 
 	if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
 	    nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) ||
@@ -826,33 +1243,26 @@ static int ctrl_fill_info(const struct genl_family *family, u32 portid, u32 seq,
 	    nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
 		goto nla_put_failure;
 
-	if (genl_get_cmd_cnt(family)) {
+	if (genl_op_iter_init(family, &i)) {
 		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 < genl_get_cmd_cnt(family); i++) {
+		while (genl_op_iter_next(&i)) {
 			struct nlattr *nest;
-			struct genl_ops op;
 			u32 op_flags;
 
-			genl_get_cmd_by_index(i, family, &op);
-			op_flags = op.flags;
-			if (op.dumpit)
-				op_flags |= GENL_CMD_CAP_DUMP;
-			if (op.doit)
-				op_flags |= GENL_CMD_CAP_DO;
-			if (op.policy)
+			op_flags = i.flags;
+			if (i.doit.policy || i.dumpit.policy)
 				op_flags |= GENL_CMD_CAP_HASPOL;
 
-			nest = nla_nest_start_noflag(skb, i + 1);
+			nest = nla_nest_start_noflag(skb, genl_op_iter_idx(&i));
 			if (nest == NULL)
 				goto nla_put_failure;
 
-			if (nla_put_u32(skb, CTRL_ATTR_OP_ID, op.cmd) ||
+			if (nla_put_u32(skb, CTRL_ATTR_OP_ID, i.cmd) ||
 			    nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags))
 				goto nla_put_failure;
 
@@ -947,6 +1357,7 @@ static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
 	struct net *net = sock_net(skb->sk);
 	int fams_to_skip = cb->args[0];
 	unsigned int id;
+	int err = 0;
 
 	idr_for_each_entry(&genl_fam_idr, rt, id) {
 		if (!rt->netnsok && !net_eq(net, &init_net))
@@ -955,16 +1366,17 @@ static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
 		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) {
+		err = ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid,
+				     cb->nlh->nlmsg_seq, NLM_F_MULTI,
+				     skb, CTRL_CMD_NEWFAMILY);
+		if (err) {
 			n--;
 			break;
 		}
 	}
 
 	cb->args[0] = n;
-	return skb->len;
+	return err;
 }
 
 static struct sk_buff *ctrl_build_family_msg(const struct genl_family *family,
@@ -1089,15 +1501,11 @@ static int genl_ctrl_event(int event, const struct genl_family *family,
 	if (IS_ERR(msg))
 		return PTR_ERR(msg);
 
-	if (!family->netnsok) {
+	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();
-	}
+	else
+		genlmsg_multicast_allns(&genl_ctrl, msg, 0, 0);
 
 	return 0;
 }
@@ -1105,10 +1513,10 @@ static int genl_ctrl_event(int event, const struct genl_family *family,
 struct ctrl_dump_policy_ctx {
 	struct netlink_policy_dump_state *state;
 	const struct genl_family *rt;
-	unsigned int opidx;
+	struct genl_op_iter *op_iter;
 	u32 op;
 	u16 fam_id;
-	u8 policies:1,
+	u8 dump_map:1,
 	   single_op:1;
 };
 
@@ -1123,10 +1531,10 @@ static int ctrl_dumppolicy_start(struct netlink_callback *cb)
 {
 	const struct genl_dumpit_info *info = genl_dumpit_info(cb);
 	struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
-	struct nlattr **tb = info->attrs;
+	struct nlattr **tb = info->info.attrs;
 	const struct genl_family *rt;
-	struct genl_ops op;
-	int err, i;
+	struct genl_op_iter i;
+	int err;
 
 	BUILD_BUG_ON(sizeof(*ctx) > sizeof(cb->ctx));
 
@@ -1150,37 +1558,74 @@ static int ctrl_dumppolicy_start(struct netlink_callback *cb)
 	ctx->rt = rt;
 
 	if (tb[CTRL_ATTR_OP]) {
+		struct genl_split_ops doit, dump;
+
 		ctx->single_op = true;
 		ctx->op = nla_get_u32(tb[CTRL_ATTR_OP]);
 
-		err = genl_get_cmd(ctx->op, rt, &op);
+		err = genl_get_cmd_both(ctx->op, rt, &doit, &dump);
 		if (err) {
 			NL_SET_BAD_ATTR(cb->extack, tb[CTRL_ATTR_OP]);
 			return err;
 		}
 
-		if (!op.policy)
+		if (doit.policy) {
+			err = netlink_policy_dump_add_policy(&ctx->state,
+							     doit.policy,
+							     doit.maxattr);
+			if (err)
+				goto err_free_state;
+		}
+		if (dump.policy) {
+			err = netlink_policy_dump_add_policy(&ctx->state,
+							     dump.policy,
+							     dump.maxattr);
+			if (err)
+				goto err_free_state;
+		}
+
+		if (!ctx->state)
 			return -ENODATA;
 
-		return netlink_policy_dump_add_policy(&ctx->state, op.policy,
-						      op.maxattr);
+		ctx->dump_map = 1;
+		return 0;
 	}
 
-	for (i = 0; i < genl_get_cmd_cnt(rt); i++) {
-		genl_get_cmd_by_index(i, rt, &op);
+	ctx->op_iter = kmalloc(sizeof(*ctx->op_iter), GFP_KERNEL);
+	if (!ctx->op_iter)
+		return -ENOMEM;
+
+	genl_op_iter_init(rt, ctx->op_iter);
+	ctx->dump_map = genl_op_iter_next(ctx->op_iter);
 
-		if (op.policy) {
+	for (genl_op_iter_init(rt, &i); genl_op_iter_next(&i); ) {
+		if (i.doit.policy) {
 			err = netlink_policy_dump_add_policy(&ctx->state,
-							     op.policy,
-							     op.maxattr);
+							     i.doit.policy,
+							     i.doit.maxattr);
 			if (err)
-				return err;
+				goto err_free_state;
+		}
+		if (i.dumpit.policy) {
+			err = netlink_policy_dump_add_policy(&ctx->state,
+							     i.dumpit.policy,
+							     i.dumpit.maxattr);
+			if (err)
+				goto err_free_state;
 		}
 	}
 
-	if (!ctx->state)
-		return -ENODATA;
+	if (!ctx->state) {
+		err = -ENODATA;
+		goto err_free_op_iter;
+	}
 	return 0;
+
+err_free_state:
+	netlink_policy_dump_free(ctx->state);
+err_free_op_iter:
+	kfree(ctx->op_iter);
+	return err;
 }
 
 static void *ctrl_dumppolicy_prep(struct sk_buff *skb,
@@ -1203,7 +1648,8 @@ static void *ctrl_dumppolicy_prep(struct sk_buff *skb,
 
 static int ctrl_dumppolicy_put_op(struct sk_buff *skb,
 				  struct netlink_callback *cb,
-			          struct genl_ops *op)
+				  struct genl_split_ops *doit,
+				  struct genl_split_ops *dumpit)
 {
 	struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
 	struct nlattr *nest_pol, *nest_op;
@@ -1211,10 +1657,7 @@ static int ctrl_dumppolicy_put_op(struct sk_buff *skb,
 	int idx;
 
 	/* skip if we have nothing to show */
-	if (!op->policy)
-		return 0;
-	if (!op->doit &&
-	    (!op->dumpit || op->validate & GENL_DONT_VALIDATE_DUMP))
+	if (!doit->policy && !dumpit->policy)
 		return 0;
 
 	hdr = ctrl_dumppolicy_prep(skb, cb);
@@ -1225,21 +1668,26 @@ static int ctrl_dumppolicy_put_op(struct sk_buff *skb,
 	if (!nest_pol)
 		goto err;
 
-	nest_op = nla_nest_start(skb, op->cmd);
+	nest_op = nla_nest_start(skb, doit->cmd);
 	if (!nest_op)
 		goto err;
 
-	/* for now both do/dump are always the same */
-	idx = netlink_policy_dump_get_policy_idx(ctx->state,
-						 op->policy,
-						 op->maxattr);
+	if (doit->policy) {
+		idx = netlink_policy_dump_get_policy_idx(ctx->state,
+							 doit->policy,
+							 doit->maxattr);
 
-	if (op->doit && nla_put_u32(skb, CTRL_ATTR_POLICY_DO, idx))
-		goto err;
+		if (nla_put_u32(skb, CTRL_ATTR_POLICY_DO, idx))
+			goto err;
+	}
+	if (dumpit->policy) {
+		idx = netlink_policy_dump_get_policy_idx(ctx->state,
+							 dumpit->policy,
+							 dumpit->maxattr);
 
-	if (op->dumpit && !(op->validate & GENL_DONT_VALIDATE_DUMP) &&
-	    nla_put_u32(skb, CTRL_ATTR_POLICY_DUMP, idx))
-		goto err;
+		if (nla_put_u32(skb, CTRL_ATTR_POLICY_DUMP, idx))
+			goto err;
+	}
 
 	nla_nest_end(skb, nest_op);
 	nla_nest_end(skb, nest_pol);
@@ -1256,31 +1704,29 @@ static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb)
 	struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
 	void *hdr;
 
-	if (!ctx->policies) {
-		while (ctx->opidx < genl_get_cmd_cnt(ctx->rt)) {
-			struct genl_ops op;
+	if (ctx->dump_map) {
+		if (ctx->single_op) {
+			struct genl_split_ops doit, dumpit;
 
-			if (ctx->single_op) {
-				int err;
+			if (WARN_ON(genl_get_cmd_both(ctx->op, ctx->rt,
+						      &doit, &dumpit)))
+				return -ENOENT;
 
-				err = genl_get_cmd(ctx->op, ctx->rt, &op);
-				if (WARN_ON(err))
-					return skb->len;
+			if (ctrl_dumppolicy_put_op(skb, cb, &doit, &dumpit))
+				return skb->len;
 
-				/* break out of the loop after this one */
-				ctx->opidx = genl_get_cmd_cnt(ctx->rt);
-			} else {
-				genl_get_cmd_by_index(ctx->opidx, ctx->rt, &op);
-			}
+			/* done with the per-op policy index list */
+			ctx->dump_map = 0;
+		}
 
-			if (ctrl_dumppolicy_put_op(skb, cb, &op))
+		while (ctx->dump_map) {
+			if (ctrl_dumppolicy_put_op(skb, cb,
+						   &ctx->op_iter->doit,
+						   &ctx->op_iter->dumpit))
 				return skb->len;
 
-			ctx->opidx++;
+			ctx->dump_map = genl_op_iter_next(ctx->op_iter);
 		}
-
-		/* completed with the per-op policy index list */
-		ctx->policies = true;
 	}
 
 	while (netlink_policy_dump_loop(ctx->state)) {
@@ -1313,18 +1759,27 @@ static int ctrl_dumppolicy_done(struct netlink_callback *cb)
 {
 	struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
 
+	kfree(ctx->op_iter);
 	netlink_policy_dump_free(ctx->state);
 	return 0;
 }
 
-static const struct genl_ops genl_ctrl_ops[] = {
+static const struct genl_split_ops genl_ctrl_ops[] = {
 	{
 		.cmd		= CTRL_CMD_GETFAMILY,
-		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
+		.validate	= GENL_DONT_VALIDATE_STRICT,
 		.policy		= ctrl_policy_family,
 		.maxattr	= ARRAY_SIZE(ctrl_policy_family) - 1,
 		.doit		= ctrl_getfamily,
+		.flags		= GENL_CMD_CAP_DO,
+	},
+	{
+		.cmd		= CTRL_CMD_GETFAMILY,
+		.validate	= GENL_DONT_VALIDATE_DUMP,
+		.policy		= ctrl_policy_family,
+		.maxattr	= ARRAY_SIZE(ctrl_policy_family) - 1,
 		.dumpit		= ctrl_dumpfamily,
+		.flags		= GENL_CMD_CAP_DUMP,
 	},
 	{
 		.cmd		= CTRL_CMD_GETPOLICY,
@@ -1333,6 +1788,7 @@ static const struct genl_ops genl_ctrl_ops[] = {
 		.start		= ctrl_dumppolicy_start,
 		.dumpit		= ctrl_dumppolicy,
 		.done		= ctrl_dumppolicy_done,
+		.flags		= GENL_CMD_CAP_DUMP,
 	},
 };
 
@@ -1342,8 +1798,9 @@ static const struct genl_multicast_group genl_ctrl_groups[] = {
 
 static struct genl_family genl_ctrl __ro_after_init = {
 	.module = THIS_MODULE,
-	.ops = genl_ctrl_ops,
-	.n_ops = ARRAY_SIZE(genl_ctrl_ops),
+	.split_ops = genl_ctrl_ops,
+	.n_split_ops = ARRAY_SIZE(genl_ctrl_ops),
+	.resv_start_op = CTRL_CMD_GETPOLICY + 1,
 	.mcgrps = genl_ctrl_groups,
 	.n_mcgrps = ARRAY_SIZE(genl_ctrl_groups),
 	.id = GENL_ID_CTRL,
@@ -1358,7 +1815,7 @@ static int genl_bind(struct net *net, int group)
 	unsigned int id;
 	int ret = 0;
 
-	genl_lock_all();
+	down_read(&cb_lock);
 
 	idr_for_each_entry(&genl_fam_idr, family, id) {
 		const struct genl_multicast_group *grp;
@@ -1372,23 +1829,60 @@ static int genl_bind(struct net *net, int group)
 			continue;
 
 		grp = &family->mcgrps[i];
-		if ((grp->flags & GENL_UNS_ADMIN_PERM) &&
+		if ((grp->flags & GENL_MCAST_CAP_NET_ADMIN) &&
 		    !ns_capable(net->user_ns, CAP_NET_ADMIN))
 			ret = -EPERM;
+		if ((grp->flags & GENL_MCAST_CAP_SYS_ADMIN) &&
+		    !ns_capable(net->user_ns, CAP_SYS_ADMIN))
+			ret = -EPERM;
+
+		if (ret)
+			break;
+
+		if (family->bind)
+			family->bind(i);
 
 		break;
 	}
 
-	genl_unlock_all();
+	up_read(&cb_lock);
 	return ret;
 }
 
+static void genl_unbind(struct net *net, int group)
+{
+	const struct genl_family *family;
+	unsigned int id;
+
+	down_read(&cb_lock);
+
+	idr_for_each_entry(&genl_fam_idr, family, id) {
+		int i;
+
+		if (family->n_mcgrps == 0)
+			continue;
+
+		i = group - family->mcgrp_offset;
+		if (i < 0 || i >= family->n_mcgrps)
+			continue;
+
+		if (family->unbind)
+			family->unbind(i);
+
+		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,
+		.release	= genl_release,
 	};
 
 	/* we'll bump the group number right afterwards */
@@ -1434,23 +1928,23 @@ problem:
 
 core_initcall(genl_init);
 
-static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
-			 gfp_t flags)
+static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group)
 {
 	struct sk_buff *tmp;
 	struct net *net, *prev = NULL;
 	bool delivered = false;
 	int err;
 
+	rcu_read_lock();
 	for_each_net_rcu(net) {
 		if (prev) {
-			tmp = skb_clone(skb, flags);
+			tmp = skb_clone(skb, GFP_ATOMIC);
 			if (!tmp) {
 				err = -ENOMEM;
 				goto error;
 			}
 			err = nlmsg_multicast(prev->genl_sock, tmp,
-					      portid, group, flags);
+					      portid, group, GFP_ATOMIC);
 			if (!err)
 				delivered = true;
 			else if (err != -ESRCH)
@@ -1459,27 +1953,31 @@ static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
 
 		prev = net;
 	}
+	err = nlmsg_multicast(prev->genl_sock, skb, portid, group, GFP_ATOMIC);
+
+	rcu_read_unlock();
 
-	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:
+	rcu_read_unlock();
+
 	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)
+			    unsigned int group)
 {
 	if (WARN_ON_ONCE(group >= family->n_mcgrps))
 		return -EINVAL;
 
 	group = family->mcgrp_offset + group;
-	return genlmsg_mcast(skb, portid, group, flags);
+	return genlmsg_mcast(skb, portid, group);
 }
 EXPORT_SYMBOL(genlmsg_multicast_allns);