1 files changed, 166 insertions, 112 deletions

diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 36e3a86..7dbc4f7 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -69,16 +69,20 @@ static struct list_head family_ht[GENL_FAM_TAB_SIZE];
  * 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.
  */
-static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_VFS_DQUOT);
+static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) |
+				      BIT(GENL_ID_VFS_DQUOT);
 static unsigned long *mc_groups = &mc_group_start;
 static unsigned long mc_groups_longs = 1;
 
 static int genl_ctrl_event(int event, struct genl_family *family,
-			   struct genl_multicast_group *grp);
+			   const struct genl_multicast_group *grp,
+			   int grp_id);
 
 static inline unsigned int genl_family_hash(unsigned int id)
 {
@@ -144,66 +148,110 @@ static u16 genl_generate_id(void)
 	return 0;
 }
 
-static struct genl_multicast_group notify_grp;
-
-/**
- * genl_register_mc_group - register a multicast group
- *
- * Registers the specified multicast group and notifies userspace
- * about the new group.
- *
- * Returns 0 on success or a negative error code.
- *
- * @family: The generic netlink family the group shall be registered for.
- * @grp: The group to register, must have a name.
- */
-int genl_register_mc_group(struct genl_family *family,
-			   struct genl_multicast_group *grp)
+static int genl_allocate_reserve_groups(int n_groups, int *first_id)
 {
-	int id;
 	unsigned long *new_groups;
-	int err = 0;
+	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;
+			}
+		}
 
-	BUG_ON(grp->name[0] == '\0');
-	BUG_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL);
+		if (id >= 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);
 
-	genl_lock_all();
+	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, 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 (grp == &notify_grp)
-		id = GENL_ID_CTRL;
-	else if (strcmp(family->name, "NET_DM") == 0)
-		id = 1;
-	else if (strcmp(family->name, "VFS_DQUOT") == 0)
-		id = GENL_ID_VFS_DQUOT;
-	else
-		id = find_first_zero_bit(mc_groups,
-					 mc_groups_longs * BITS_PER_LONG);
-
-
-	if (id >= mc_groups_longs * BITS_PER_LONG) {
-		size_t nlen = (mc_groups_longs + 1) * sizeof(unsigned long);
-
-		if (mc_groups == &mc_group_start) {
-			new_groups = kzalloc(nlen, GFP_KERNEL);
-			if (!new_groups) {
-				err = -ENOMEM;
-				goto out;
-			}
-			mc_groups = new_groups;
-			*mc_groups = mc_group_start;
-		} else {
-			new_groups = krealloc(mc_groups, nlen, GFP_KERNEL);
-			if (!new_groups) {
-				err = -ENOMEM;
-				goto out;
-			}
-			mc_groups = new_groups;
-			mc_groups[mc_groups_longs] = 0;
-		}
-		mc_groups_longs++;
+	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 (strcmp(family->name, "VFS_DQUOT") == 0) {
+		first_id = GENL_ID_VFS_DQUOT;
+		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;
 
@@ -219,9 +267,7 @@ int genl_register_mc_group(struct genl_family *family,
 				 * number of _possible_ groups has been
 				 * increased on some sockets which is ok.
 				 */
-				rcu_read_unlock();
-				netlink_table_ungrab();
-				goto out;
+				break;
 			}
 		}
 		rcu_read_unlock();
@@ -229,46 +275,39 @@ int genl_register_mc_group(struct genl_family *family,
 	} else {
 		err = netlink_change_ngroups(init_net.genl_sock,
 					     mc_groups_longs * BITS_PER_LONG);
-		if (err)
-			goto out;
 	}
 
-	grp->id = id;
-	set_bit(id, mc_groups);
-	list_add_tail(&grp->list, &family->mcast_groups);
+	if (groups_allocated && err) {
+		for (i = 0; i < family->n_mcgrps; i++)
+			clear_bit(family->mcgrp_offset + i, mc_groups);
+	}
 
-	genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family, grp);
- out:
-	genl_unlock_all();
 	return err;
 }
-EXPORT_SYMBOL(genl_register_mc_group);
 
-static void __genl_unregister_mc_group(struct genl_family *family,
-				       struct genl_multicast_group *grp)
+static void genl_unregister_mc_groups(struct genl_family *family)
 {
 	struct net *net;
+	int i;
 
 	netlink_table_grab();
 	rcu_read_lock();
-	for_each_net_rcu(net)
-		__netlink_clear_multicast_users(net->genl_sock, grp->id);
+	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();
 
-	if (grp->id != 1)
-		clear_bit(grp->id, mc_groups);
-	list_del(&grp->list);
-	genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family, grp);
-	grp->id = 0;
-}
-
-static void genl_unregister_mc_groups(struct genl_family *family)
-{
-	struct genl_multicast_group *grp, *tmp;
+	for (i = 0; i < family->n_mcgrps; i++) {
+		int grp_id = family->mcgrp_offset + i;
 
-	list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list)
-		__genl_unregister_mc_group(family, grp);
+		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(struct genl_family *family)
@@ -314,7 +353,7 @@ static int genl_validate_ops(struct genl_family *family)
  */
 int __genl_register_family(struct genl_family *family)
 {
-	int err = -EINVAL;
+	int err = -EINVAL, i;
 
 	if (family->id && family->id < GENL_MIN_ID)
 		goto errout;
@@ -326,8 +365,6 @@ int __genl_register_family(struct genl_family *family)
 	if (err)
 		return err;
 
-	INIT_LIST_HEAD(&family->mcast_groups);
-
 	genl_lock_all();
 
 	if (genl_family_find_byname(family->name)) {
@@ -359,10 +396,18 @@ int __genl_register_family(struct genl_family *family)
 	} else
 		family->attrbuf = NULL;
 
+	err = genl_validate_assign_mc_groups(family);
+	if (err)
+		goto errout_locked;
+
 	list_add_tail(&family->family_list, genl_family_chain(family->id));
 	genl_unlock_all();
 
-	genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL);
+	/* 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;
 
@@ -398,7 +443,7 @@ int genl_unregister_family(struct genl_family *family)
 		genl_unlock_all();
 
 		kfree(family->attrbuf);
-		genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL);
+		genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0);
 		return 0;
 	}
 
@@ -658,23 +703,26 @@ static int ctrl_fill_info(struct genl_family *family, u32 portid, u32 seq,
 		nla_nest_end(skb, nla_ops);
 	}
 
-	if (!list_empty(&family->mcast_groups)) {
-		struct genl_multicast_group *grp;
+	if (family->n_mcgrps) {
 		struct nlattr *nla_grps;
-		int idx = 1;
+		int i;
 
 		nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
 		if (nla_grps == NULL)
 			goto nla_put_failure;
 
-		list_for_each_entry(grp, &family->mcast_groups, list) {
+		for (i = 0; i < family->n_mcgrps; i++) {
 			struct nlattr *nest;
+			const struct genl_multicast_group *grp;
 
-			nest = nla_nest_start(skb, idx++);
+			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, grp->id) ||
+			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;
@@ -692,9 +740,9 @@ nla_put_failure:
 }
 
 static int ctrl_fill_mcgrp_info(struct genl_family *family,
-				struct genl_multicast_group *grp, u32 portid,
-				u32 seq, u32 flags, struct sk_buff *skb,
-				u8 cmd)
+				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;
@@ -716,7 +764,7 @@ static int ctrl_fill_mcgrp_info(struct genl_family *family,
 	if (nest == NULL)
 		goto nla_put_failure;
 
-	if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id) ||
+	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;
@@ -782,9 +830,10 @@ static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
 	return skb;
 }
 
-static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_family *family,
-					    struct genl_multicast_group *grp,
-					    u32 portid, int seq, u8 cmd)
+static struct sk_buff *
+ctrl_build_mcgrp_msg(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;
@@ -793,7 +842,8 @@ static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_family *family,
 	if (skb == NULL)
 		return ERR_PTR(-ENOBUFS);
 
-	err = ctrl_fill_mcgrp_info(family, grp, portid, seq, 0, skb, cmd);
+	err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid,
+				   seq, 0, skb, cmd);
 	if (err < 0) {
 		nlmsg_free(skb);
 		return ERR_PTR(err);
@@ -856,7 +906,8 @@ static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
 }
 
 static int genl_ctrl_event(int event, struct genl_family *family,
-			   struct genl_multicast_group *grp)
+			   const struct genl_multicast_group *grp,
+			   int grp_id)
 {
 	struct sk_buff *msg;
 
@@ -873,7 +924,7 @@ static int genl_ctrl_event(int event, struct genl_family *family,
 	case CTRL_CMD_NEWMCAST_GRP:
 	case CTRL_CMD_DELMCAST_GRP:
 		BUG_ON(!grp);
-		msg = ctrl_build_mcgrp_msg(family, grp, 0, 0, event);
+		msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event);
 		break;
 	default:
 		return -EINVAL;
@@ -884,11 +935,11 @@ static int genl_ctrl_event(int event, struct genl_family *family,
 
 	if (!family->netnsok) {
 		genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0,
-					GENL_ID_CTRL, GFP_KERNEL);
+					0, GFP_KERNEL);
 	} else {
 		rcu_read_lock();
 		genlmsg_multicast_allns(&genl_ctrl, msg, 0,
-					GENL_ID_CTRL, GFP_ATOMIC);
+					0, GFP_ATOMIC);
 		rcu_read_unlock();
 	}
 
@@ -904,8 +955,8 @@ static struct genl_ops genl_ctrl_ops[] = {
 	},
 };
 
-static struct genl_multicast_group notify_grp = {
-	.name		= "notify",
+static struct genl_multicast_group genl_ctrl_groups[] = {
+	{ .name = "notify", },
 };
 
 static int __net_init genl_pernet_init(struct net *net)
@@ -945,7 +996,8 @@ static int __init genl_init(void)
 	for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
 		INIT_LIST_HEAD(&family_ht[i]);
 
-	err = genl_register_family_with_ops(&genl_ctrl, genl_ctrl_ops);
+	err = genl_register_family_with_ops_groups(&genl_ctrl, genl_ctrl_ops,
+						   genl_ctrl_groups);
 	if (err < 0)
 		goto problem;
 
@@ -953,10 +1005,6 @@ static int __init genl_init(void)
 	if (err)
 		goto problem;
 
-	err = genl_register_mc_group(&genl_ctrl, &notify_grp);
-	if (err < 0)
-		goto problem;
-
 	return 0;
 
 problem:
@@ -997,6 +1045,9 @@ static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
 int genlmsg_multicast_allns(struct genl_family *family, struct sk_buff *skb,
 			    u32 portid, unsigned int group, gfp_t flags)
 {
+	if (group >= family->n_mcgrps)
+		return -EINVAL;
+	group = family->mcgrp_offset + group;
 	return genlmsg_mcast(skb, portid, group, flags);
 }
 EXPORT_SYMBOL(genlmsg_multicast_allns);
@@ -1011,6 +1062,9 @@ void genl_notify(struct genl_family *family,
 	if (nlh)
 		report = nlmsg_report(nlh);
 
+	if (group >= family->n_mcgrps)
+		return;
+	group = family->mcgrp_offset + group;
 	nlmsg_notify(sk, skb, portid, group, report, flags);
 }
 EXPORT_SYMBOL(genl_notify);