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Ed W <lists@××××××××××.com> 2010-03-03 18:41: |
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> On 03/03/2010 17:35, Natanael Copa wrote: |
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>> On Wed, Mar 3, 2010 at 5:14 PM, Ed W<lists@××××××××××.com> wrote: |
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>> |
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>> |
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>>> I don't have physical access to all machines, so any interesting cheap |
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>>> random number generator dongles would be interesting to know about, but will |
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>>> not be a full solution in this case. If I'm missing some obvious option |
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>>> which is available on recent Intel/AMD hardware which might give me larger |
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>>> amounts of entropy then please shout? |
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>>> |
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>> media-sound/audio-entropyd? |
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>> |
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>> |
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> |
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> Thanks for the idea - the server is a rackmount thing rented from a |
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> hosting company and I don't think it has any soundcard onboard... |
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> |
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> I believe that the kernel doesn't use the network interrupt for |
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> randomness, only keyboard, mouse and HD. This isn't a great situation |
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> for a headless, mouseless webserver which tries as hard as possible not |
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> to touch the disk... |
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> |
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> I ordered an "Entropy Key" from here: http://www.entropykey.co.uk/ |
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> |
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> This will help for the office server, but it doesn't really sort out my |
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> rented racks (no, don't really want some crazy solution involving ssh |
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> piping the data to it...) |
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> |
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> Would be very grateful for any other ideas here. I think the solution is |
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> likely to use a lower quality rng source for the SSP protection rather |
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> than generating more entropy - I'm not really see that a super high |
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> quality rng source is really needed for SSP? Possibly a local attacker |
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> can write code which flogs the rng until they figure out the params, |
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> then use it as part of an SSP attack, however, its low on my list of |
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> fears... |
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> |
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> I can see that glibc previously used to use erandom, but this patch was |
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> dropped - any reason? |
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> |
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> Cheers |
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> |
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> Ed W |
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|
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Interesting subject. |
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|
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Here's [1] another technique I found to make use of the rng in the TPM if it's |
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available. Seems to be working fairly well in my tests so far [3], though I |
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think I'd prefer an entropy key as well. From some other reading [2] it |
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seems that the virtio-rng modules (for use with qemu/kvm based guests) |
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can make use of a host side /dev/hw_random device which I believe the |
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entropy key provides. The TPM currently does not, though may in the |
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future. |
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|
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Cheers, |
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Brian |
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|
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[1] http://www.outflux.net/blog/archives/2010/02/08/rng-tools-with-tpm/ |
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[2] http://lwn.net/Articles/283103/ |
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[3] I was able to enable it in the BIOS using the IPMI SOL, so hopefully |
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you won't need physical access. Not doing anything like TrustedGrub |
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yet. To be honest, I don't really see the point. Feel free to |
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enlighten me. |
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