Messages in this thread | | | From | Linus Torvalds <> | Date | Sun, 31 Mar 2019 07:52:28 -0700 | Subject | Re: [PATCH v2 0/5] pid: add pidfd_open() |
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On Sat, Mar 30, 2019 at 9:47 PM Jann Horn <jannh@google.com> wrote: > > Sure, given a pidfd_clone() syscall, as long as the parent of the > process is giving you a pidfd for it and you don't have to deal with > grandchildren created by fork() calls outside your control, that > works.
Don't do pidfd_clone() and pidfd_wait().
Both of those existing system calls already get a "flags" argument. Just make a WPIDFD (for waitid) and CLONE_PIDFD (for clone) bit, and make the existing system calls just take/return a pidfd.
Side note: we could (should?) also make the default maxpid just be larger. It needs to fit in an 'int', but MAXINT instead of 65535 would likely alreadt make a lot of these attacks harder.
There was some really old legacy reason why we actually limited it to 65535 originally. It was old and crufty even back when..
Linus
Linus
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