In the Linux kernel, the following vulnerability has been resolved: fou: Fix null-ptr-deref in GRO. We observed a null-ptr-deref in fou_gro_receive() while shutting down a host. [0] The NULL poin…

Summary

In the Linux kernel, the following vulnerability has been resolved: fou: Fix null-ptr-deref in GRO. We observed a null-ptr-deref in fou_gro_receive() while shutting down a host. [0] The NULL pointer is sk->sk_user_data, and the offset 8 is of protocol in struct fou. When fou_release() is called due to netns dismantle or explicit tunnel teardown, udp_tunnel_sock_release() sets NULL to sk->sk_user_data. Then, the tunnel socket is destroyed after a single RCU grace period. So, in-flight udp4…