CVE-2022-49732: 
Linux Kernel vulnerability analysis and mitigation

In the Linux kernel, a vulnerability was discovered related to socket protocol handling. The issue stems from a change in the psock vs ULP (Upper Layer Protocol) protection check mechanism. The vulnerability was introduced by commit 8a59f9d1e3d4 which moved the inetcskhasulp(sk) check from skpsockinit() to tcpbpfupdateproto() function (Kernel Commit).

The vulnerability occurs when the destruction path for psock includes the ULP unwind. When ULP is present, the system calls tcpupdateulp() with the skproto of the ULP itself, which results in the ULP looping its callbacks. This happens because the inetcskhasulp(sk) check was moved from skpsockinit() to the new tcpbpfupdate_proto() function, presumably to allow creating psocks for non-inet sockets (Kernel Commit).

The vulnerability could lead to a callback loop in the ULP (Upper Layer Protocol) handling, potentially causing system instability or denial of service conditions when processing network sockets (Kernel Commit).

The issue has been fixed by moving the protection check back to skpsockinit() and adding a new skisinet() helper function. The fix ensures that skpsockinit() fails early if ULP is already present, preventing the callback loop condition (Kernel Commit).