From 9f30831390ede02d9fcd54fd9ea5a585ab649f4a Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 9 Feb 2024 18:12:48 +0000 Subject: net: add rcu safety to rtnl_prop_list_size() rtnl_prop_list_size() can be called while alternative names are added or removed concurrently. if_nlmsg_size() / rtnl_calcit() can indeed be called without RTNL held. Use explicit RCU protection to avoid UAF. Fixes: 88f4fb0c7496 ("net: rtnetlink: put alternative names to getlink message") Signed-off-by: Eric Dumazet Cc: Jiri Pirko Link: https://lore.kernel.org/r/20240209181248.96637-1-edumazet@google.com Signed-off-by: Jakub Kicinski --- net/core/rtnetlink.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) (limited to 'net/core/rtnetlink.c') diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index f6f29eb03ec2..9c4f427f3a50 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -1020,14 +1020,17 @@ static size_t rtnl_xdp_size(void) static size_t rtnl_prop_list_size(const struct net_device *dev) { struct netdev_name_node *name_node; - size_t size; + unsigned int cnt = 0; + + rcu_read_lock(); + list_for_each_entry_rcu(name_node, &dev->name_node->list, list) + cnt++; + rcu_read_unlock(); - if (list_empty(&dev->name_node->list)) + if (!cnt) return 0; - size = nla_total_size(0); - list_for_each_entry(name_node, &dev->name_node->list, list) - size += nla_total_size(ALTIFNAMSIZ); - return size; + + return nla_total_size(0) + cnt * nla_total_size(ALTIFNAMSIZ); } static size_t rtnl_proto_down_size(const struct net_device *dev) -- cgit