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Change History

In the Linux kernel, the following vulnerability has been resolved:

ovpn: fix possible use-after-free in ovpn_net_xmit

When building the skb_list in ovpn_net_xmit, skb_share_check will free
the original skb if it is shared. The current implementation continues
to use the stale skb pointer for subsequent operations:
- peer lookup,
- skb_dst_drop (even though all segments produced by skb_gso_segment
  will have a dst attached),
- ovpn_peer_stats_increment_tx.

Fix this by moving the peer lookup and skb_dst_drop before segmentation
so that the original skb is still valid when used. Return early if all
segments fail skb_share_check and the list ends up empty.
Also switch ovpn_peer_stats_increment_tx to use skb_list.next; the next
patch fixes the stats logic.

https://git.kernel.org/stable/c/3e4fbcb4e078915367ba5576cd70d76dbc970f95

https://git.kernel.org/stable/c/442915c96a9bff1c7080e2aedabb1c03faa28d81

https://git.kernel.org/stable/c/a5ec7baa44ea3a1d6aa0ca31c0ad82edf9affe41