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| author | Eric Dumazet <edumazet@google.com> | 2022-01-31 17:21:06 -0800 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2022-02-01 20:19:00 -0800 |
| commit | c6f6f2444bdbe0079e41914a35081530d0409963 (patch) | |
| tree | a092807eddace8b3d89c808d4f65071057bfb8e1 /net/core | |
| parent | 04c2a47ffb13c29778e2a14e414ad4cb5a5db4b5 (diff) | |
| download | linux-stable-c6f6f2444bdbe0079e41914a35081530d0409963.tar.gz linux-stable-c6f6f2444bdbe0079e41914a35081530d0409963.tar.bz2 linux-stable-c6f6f2444bdbe0079e41914a35081530d0409963.zip | |
rtnetlink: make sure to refresh master_dev/m_ops in __rtnl_newlink()
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.
Fixes: ba7d49b1f0f8 ("rtnetlink: provide api for getting and setting slave info")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20220201012106.216495-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/rtnetlink.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index e476403231f0..710da8a36729 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 @@ replay: else dev = NULL; + master_dev = NULL; + m_ops = NULL; if (dev) { master_dev = netdev_master_upper_dev_get(dev); if (master_dev) |