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    SubjectRe: [PATCH -v5] random: introduce getrandom(2) system call
    On Thu, Jul 24, 2014 at 08:21:38AM -0700, Andy Lutomirski wrote:
    > >
    > > Should we add E<SOMETHING> to be able to deny access to GRND_RANDOM or some
    > > future extension ?
    >
    > This might actually be needed sooner rather than later. There are
    > programs that use containers and intentionally don't pass /dev/random
    > through into the container. I know that Sandstorm does this, and I
    > wouldn't be surprised if other things (Docker?) do the same thing.

    I wouldn't add the error to the man page until we actually modify the
    kernel to add such a restriction.

    However, the thought crossed my mind a while back that perhaps the
    right answer is a cgroup controller which controls the rate at which a
    process is allowed to drain entropy from the /dev/random pool. This
    could be set to 0, or it could be set to N bits per unit time T, and
    if the process exceeded the value, it would just block or return
    EAGAIN. So instead of making it be just a binary "you have access" or
    "you don't", it would actually be a kernel resource that could be
    controlled just like disk bandwidth, networking bandwidth, memory, and
    CPU time.

    Then I decided that it was overkill, but for people who are trying to
    treat containers as a way to divide up OS resources between mutually
    suspicious customers in a fashion which is more efficient thatn using
    VM's, maybe it is something that someone will want to implement.

    - Ted


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