CVE-2022-49669 Information

Description

In the Linux kernel the following vulnerability has been resolved:

mptcp: fix race on unaccepted mptcp sockets

When the listener socket owning the relevant request is closed it frees the unaccepted subflows and that causes later deletion of the paired MPTCP sockets.

The mptcp socket’s worker can run in the time interval between such delete operations. When that happens any access to msk->first will cause an UaF access as the subflow cleanup did not cleared such field in the mptcp socket.

Address the issue explicitly traversing the listener socket accept queue at close time and performing the needed cleanup on the pending msk.

Note that the locking is a bit tricky as we need to acquire the msk socket lock while still owning the subflow socket one.

Reference

https://git.kernel.org/stable/c/6aeed9045071f2252ff4e98fc13d1e304f33e5b0 https://git.kernel.org/stable/c/a8a3e95c74e48c2c9b07b81fafda9122993f2e12