Message ID | 20220201012106.216495-1-eric.dumazet@gmail.com (mailing list archive) |
---|---|
State | Accepted |
Commit | c6f6f2444bdbe0079e41914a35081530d0409963 |
Delegated to: | Netdev Maintainers |
Headers | show |
Series | [net] rtnetlink: make sure to refresh master_dev/m_ops in __rtnl_newlink() | expand |
Hello: This patch was applied to netdev/net.git (master) by Jakub Kicinski <kuba@kernel.org>: On Mon, 31 Jan 2022 17:21:06 -0800 you wrote: > From: Eric Dumazet <edumazet@google.com> > > While looking at one unrelated syzbot bug, I found the replay logic > in __rtnl_newlink() to potentially trigger use-after-free. > > It is better to clear master_dev and m_ops inside the loop, > in case we have to replay it. > > [...] Here is the summary with links: - [net] rtnetlink: make sure to refresh master_dev/m_ops in __rtnl_newlink() https://git.kernel.org/netdev/net/c/c6f6f2444bdb You are awesome, thank you!
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index e476403231f00053e1a261f31a8760325c75c941..710da8a36729d6a9293b610b029bd33aa38d6514 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -3275,8 +3275,8 @@ static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, struct nlattr *slave_attr[RTNL_SLAVE_MAX_TYPE + 1]; unsigned char name_assign_type = NET_NAME_USER; struct nlattr *linkinfo[IFLA_INFO_MAX + 1]; - const struct rtnl_link_ops *m_ops = NULL; - struct net_device *master_dev = NULL; + const struct rtnl_link_ops *m_ops; + struct net_device *master_dev; struct net *net = sock_net(skb->sk); const struct rtnl_link_ops *ops; struct nlattr *tb[IFLA_MAX + 1]; @@ -3314,6 +3314,8 @@ static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, else dev = NULL; + master_dev = NULL; + m_ops = NULL; if (dev) { master_dev = netdev_master_upper_dev_get(dev); if (master_dev)