Commit aa4ad7c3 authored by Yuyang Huang's avatar Yuyang Huang Committed by Jakub Kicinski
Browse files

netlink: correct nlmsg size for multicast notifications 



Corrected the netlink message size calculation for multicast group
join/leave notifications. The previous calculation did not account for
the inclusion of both IPv4/IPv6 addresses and ifa_cacheinfo in the
payload. This fix ensures that the allocated message size is
sufficient to hold all necessary information.

This patch also includes the following improvements:
* Uses GFP_KERNEL instead of GFP_ATOMIC when holding the RTNL mutex.
* Uses nla_total_size(sizeof(struct in6_addr)) instead of
  nla_total_size(16).
* Removes unnecessary EXPORT_SYMBOL().

Fixes: 2c2b61d2 ("netlink: add IGMP/MLD join/leave notifications")
Cc: Maciej Żenczykowski <maze@google.com>
Cc: Lorenzo Colitti <lorenzo@google.com>
Signed-off-by: default avatarYuyang Huang <yuyanghuang@google.com>
Link: https://patch.msgid.link/20241221100007.1910089-1-yuyanghuang@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent f288c7a1

net/ipv4/igmp.c

+4 −2
Original line number Diff line number Diff line
@@ -1473,7 +1473,9 @@ static void inet_ifmcaddr_notify(struct net_device *dev, 
	int err = -ENOMEM;



	skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) +

			nla_total_size(sizeof(__be32)), GFP_ATOMIC);

			nla_total_size(sizeof(__be32)) +

			nla_total_size(sizeof(struct ifa_cacheinfo)),

			GFP_KERNEL);

	if (!skb)

		goto error;
@@ -1484,7 +1486,7 @@ static void inet_ifmcaddr_notify(struct net_device *dev, 
		goto error;

	}



	rtnl_notify(skb, net, 0, RTNLGRP_IPV4_MCADDR, NULL, GFP_ATOMIC);

	rtnl_notify(skb, net, 0, RTNLGRP_IPV4_MCADDR, NULL, GFP_KERNEL);

	return;

error:

	rtnl_set_sk_err(net, RTNLGRP_IPV4_MCADDR, err);

net/ipv6/addrconf.c

+0 −1
Original line number Diff line number Diff line
@@ -5239,7 +5239,6 @@ int inet6_fill_ifmcaddr(struct sk_buff *skb, 
	nlmsg_end(skb, nlh);

	return 0;

}

EXPORT_SYMBOL(inet6_fill_ifmcaddr);



static int inet6_fill_ifacaddr(struct sk_buff *skb,

			       const struct ifacaddr6 *ifaca,

net/ipv6/mcast.c

+4 −2
Original line number Diff line number Diff line
@@ -920,7 +920,9 @@ static void inet6_ifmcaddr_notify(struct net_device *dev, 
	int err = -ENOMEM;



	skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) +

			nla_total_size(16), GFP_ATOMIC);

			nla_total_size(sizeof(struct in6_addr)) +

			nla_total_size(sizeof(struct ifa_cacheinfo)),

			GFP_KERNEL);

	if (!skb)

		goto error;
@@ -931,7 +933,7 @@ static void inet6_ifmcaddr_notify(struct net_device *dev, 
		goto error;

	}



	rtnl_notify(skb, net, 0, RTNLGRP_IPV6_MCADDR, NULL, GFP_ATOMIC);

	rtnl_notify(skb, net, 0, RTNLGRP_IPV6_MCADDR, NULL, GFP_KERNEL);

	return;

error:

	rtnl_set_sk_err(net, RTNLGRP_IPV6_MCADDR, err);