Linux Kernel Psock and ULP Protection Check Vulnerability

A vulnerability in the Linux kernel's socket handling has been addressed. The issue arose from a change that moved the user-layer protocol (ULP) check for internet sockets to a new function, allowing for the creation of protocol sockets (psocks) for non-internet sockets. However, this change disrupted the proper initialization of psocks when ULP was already present, potentially causing a loop in ULP callbacks. The vulnerability has been resolved by ensuring that the psock initialization fails if ULP is already active, preventing the subsequent ULP unwind from disrupting the socket's protocol handling.

Impact

Exploitation of this vulnerability could lead to improper handling of protocol sockets, causing user-layer protocol callbacks to loop indefinitely, which could disrupt normal socket operations and potentially lead to a denial-of-service condition.