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    SubjectRe: IRQF_SAMPLE_RANDOM question...
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    On Tue, 2009-04-07 at 07:16 -0400, Robin Getz wrote:
    > On Mon 6 Apr 2009 15:01, Matt Mackall pondered:
    > > On Mon, 2009-04-06 at 14:30 -0400, Robin Getz wrote:
    > > > We have lots of embedded headless systems (no keyboard/mouse, no
    > > > soundcard, no video) systems with *no* sources of entropy - and
    > > > people using SSL.
    > >
    > > I'd rather add a random_sample_network call somewhere reasonably central
    > > in the network stack. Then we can use the knowledge that the sample is
    > > network-connected in the random core to decide how to measure its
    > > entropy. The trouble with IRQF_SAMPLE_RANDOM is that many of its users
    > > are technically bogus as entropy sources in the current model.
    >
    > OK - that makes more sense.
    >
    > Does that mean we also shouldn't be using IRQF_SAMPLE_RANDOM on interrupt
    > sources in subsystems which already have add_xxx_randomness() in them? (block
    > devices, and input devices?)
    >
    > block/blk-core.c -> blk_end_io() -> add_disk_randomness()
    > drivers/input/input.c -> input_event() -> add_input_randomness()
    >
    > drivers/block/xen-blkfront.c, line 639
    >
    > drivers/input/touchscreen/wm97xx-core.c, line 374
    > drivers/input/keyboard/gpio_keys.c, line 145
    > drivers/input/keyboard/bf54x-keys.c, line 255
    > drivers/input/serio/hp_sdc.c, line 881

    Yes. The flag needs to be taken out and shot. Everything going into the
    RNG should be made to go through an add_*_randomness interface only.
    Preferably not at a per-driver level.

    --
    http://selenic.com : development and support for Mercurial and Linux




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