In the Linux kernel, the following vulnerability has been resolved:
sctp: close UDP tunnel sockets during netns teardown
proc_sctp_do_udp_port() starts per-net SCTP UDP tunneling sockets when net.sctp.udp_port is set, and stops/restarts them when the sysctl value changes. The netns exit path does not stop these sockets, so a namespace can be torn down while its SCTP UDP tunnel sockets are still installed.
Close the UDP tunnel sockets from sctp_ctrlsock_exit() after unregistering the per-net sysctl table. This prevents new sysctl writes from racing in while the sockets are being released, and closes the sockets before the control socket is destroyed.
References
- https://git.kernel.org/stable/c/37ff9794be48d0caa37687e04d09675f9c849121
- https://git.kernel.org/stable/c/3bf0e349cbb4f975f35eb22753acc346b89c66a0
- https://git.kernel.org/stable/c/8ff78591d309c50a4fdab683b68dd8d512a270dd
- https://git.kernel.org/stable/c/c6eb2d615210b80339548ab07c0230edaab9a6c7
- https://git.kernel.org/stable/c/ffb2bd7ade36ec4da32c46a6eddbf4515316d08c