From: Jiayuan Chen <[email protected]>

Similar to commit 950803f72547 ("bonding: fix type confusion in
bond_setup_by_slave()") team has the same class of header_ops type
confusion.

For non-Ethernet ports, team_setup_by_port() copies port_dev->header_ops
directly. When the team device later calls dev_hard_header() or
dev_parse_header(), these callbacks can run with the team net_device
instead of the real lower device, so netdev_priv(dev) is interpreted as
the wrong private type and can crash.

Fix this by introducing team header_ops wrappers for create/parse,
selecting a team port under RCU, and calling the lower device callbacks
with port->dev, so each callback always sees the correct net_device
context.

Also pass the selected lower device to the lower parse callback, so
recursion is bounded in stacked non-Ethernet topologies and parse
callbacks always run with the correct device context.

Fixes: 1d76efe1577b ("team: add support for non-ethernet devices")
Reported-by: [email protected]
Closes: 
https://lore.kernel.org/all/[email protected]/T/
Cc: Jiayuan Chen <[email protected]>
Signed-off-by: Jiayuan Chen <[email protected]>
---
 drivers/net/team/team_core.c | 60 +++++++++++++++++++++++++++++++++++-
 1 file changed, 59 insertions(+), 1 deletion(-)

diff --git a/drivers/net/team/team_core.c b/drivers/net/team/team_core.c
index b7282f5c9632..b3f659ed06ca 100644
--- a/drivers/net/team/team_core.c
+++ b/drivers/net/team/team_core.c
@@ -2058,6 +2058,64 @@ static const struct ethtool_ops team_ethtool_ops = {
  * rt netlink interface
  ***********************/
 
+/* For tx path we need a linkup && enabled port; for parse any port suffices. 
*/
+static struct team_port *team_header_port_get_rcu(struct team *team, bool 
txable)
+{
+       struct team_port *port;
+
+       list_for_each_entry_rcu(port, &team->port_list, list) {
+               if (!txable || team_port_txable(port))
+                       return port;
+       }
+
+       return NULL;
+}
+
+static int team_header_create(struct sk_buff *skb, struct net_device *team_dev,
+                             unsigned short type, const void *daddr,
+                             const void *saddr, unsigned int len)
+{
+       struct team *team = netdev_priv(team_dev);
+       const struct header_ops *port_ops;
+       struct team_port *port;
+       int ret = 0;
+
+       rcu_read_lock();
+       port = team_header_port_get_rcu(team, true);
+       if (port) {
+               port_ops = READ_ONCE(port->dev->header_ops);
+               if (port_ops && port_ops->create)
+                       ret = port_ops->create(skb, port->dev,
+                                              type, daddr, saddr, len);
+       }
+       rcu_read_unlock();
+       return ret;
+}
+
+static int team_header_parse(const struct sk_buff *skb, const struct 
net_device *dev,
+                            unsigned char *haddr)
+{
+       struct team *team = netdev_priv(dev);
+       const struct header_ops *port_ops;
+       struct team_port *port;
+       int ret = 0;
+
+       rcu_read_lock();
+       port = team_header_port_get_rcu(team, false);
+       if (port) {
+               port_ops = READ_ONCE(port->dev->header_ops);
+               if (port_ops && port_ops->parse)
+                       ret = port_ops->parse(skb, port->dev, haddr);
+       }
+       rcu_read_unlock();
+       return ret;
+}
+
+static const struct header_ops team_header_ops = {
+       .create         = team_header_create,
+       .parse          = team_header_parse,
+};
+
 static void team_setup_by_port(struct net_device *dev,
                               struct net_device *port_dev)
 {
@@ -2066,7 +2124,7 @@ static void team_setup_by_port(struct net_device *dev,
        if (port_dev->type == ARPHRD_ETHER)
                dev->header_ops = team->header_ops_cache;
        else
-               dev->header_ops = port_dev->header_ops;
+               dev->header_ops = port_dev->header_ops ? &team_header_ops : 
NULL;
        dev->type = port_dev->type;
        dev->hard_header_len = port_dev->hard_header_len;
        dev->needed_headroom = port_dev->needed_headroom;
-- 
2.43.0


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