CyberRota Analysis
AI-GeneratedThe vulnerability affects the Linux kernel's handling of FOU (Forwarding User) sockets, specifically in the fou_create() function, which improperly manages memory during error handling. This can lead to a use-after-free condition, allowing a concurrent process to dereference a freed object, potentially resulting in system instability or exploitation. Organizations using Linux systems with FOU socket configurations should prioritize addressing this vulnerability to mitigate risks associated with memory management flaws.
Original NVD Description
In the Linux kernel, the following vulnerability has been resolved: fou: Fix use-after-free in fou_create() fou_create() publishes struct fou through sk_user_data before adding the new FOU port to the per-netns list. If fou_add_to_port_list() fails, the error path frees fou while it is still reachable through sk_user_data. A concurrent receive can then dereference the freed object in fou_from_sock(). This ordering issue was previously noted in the linked discussion. The failure is reachable when local port 0 is requested. Each socket binds to a different ephemeral port, but fou_cfg_cmp() compares the requested port 0 and reports -EALREADY once an entry already exists. Release the tunnel socket before freeing fou so sk_user_data is cleared first, and defer reclamation with kfree_rcu() to protect concurrent RCU readers. This matches the lifetime handling in fou_release().