• Paolo Abeni's avatar
    mptcp: fix race on unaccepted mptcp sockets · 6aeed904
    Paolo Abeni authored
    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.
    
    Fixes: 86e39e04 ("mptcp: keep track of local endpoint still available for each msk")
    Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
    Signed-off-by: default avatarMat Martineau <mathew.j.martineau@linux.intel.com>
    Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
    6aeed904
protocol.c 96.5 KB