On Thu, Mar 16, 2023 at 3:34 PM Eric Dumazet <edumazet@xxxxxxxxxx> wrote: > > On Thu, Mar 16, 2023 at 6:16 AM Alexander Mikhalitsyn > <aleksandr.mikhalitsyn@xxxxxxxxxxxxx> wrote: > > > > Implement SCM_PIDFD, a new type of CMSG type analogical to SCM_CREDENTIALS, > > but it contains pidfd instead of plain pid, which allows programmers not > > to care about PID reuse problem. > > Hi Alexander Hi Eric Thanks for the fast reply! ;-) > > This would add yet another conditional in af_unix fast path. > > It seems that we already can use pidfd_open() (since linux-5.3), and > pass the resulting fd in af_unix SCM_RIGHTS message ? Yes, it's possible, but it means that from the receiver side we need to trust the sent pidfd (in SCM_RIGHTS), or always use combination of SCM_RIGHTS+SCM_CREDENTIALS, then we can extract pidfd from SCM_RIGHTS, then acquire plain pid from pidfd and after compare it with the pid from SCM_CREDENTIALS. > > If you think this is not suitable, it should at least be mentioned in > the changelog. Kind regards, Alex > > Thanks.
