Re: Why does reading from /dev/urandom deplete entropy so much?

Alan, are you sure you're not talking about Helge Deller's attempt to
push a Time-based UUID generator into the kernel because you can get
duplicates from the current userspace library?

Yes

I've not heard of *any* claim where the kernel uuid random generator
has been returning duplicates.

Then the original reports got lost somewhere.

The Fedora tools use a kernel random uuid for system identifiers (to
preserve anonymity while allowing system profiles etc to be generated and
to know which are duplicates).

We seen a huge number of duplicates for certain values:

From Mike McGrath (added to Cc)

Here's the top 5:

266 28caf2c3-9766-4fe1-9e4c-d6b0ba8a0132
336 810e7126-1c69-4aff-b8b1-9db0fa8aa15a
402 c8dbb9d3-a9bd-4ba6-b92e-4a294ba5a95f
884 06e84493-e024-44b1-9b32-32d78af04039
931 e2b67e1d-e325-4740-b938-795addb45280

The left number is times this month someone has submitted a profile with
that UUID. If we take the last one as an example has come from over 800
IP's in the last 20 days. It seems very unlikely that one person would
find his way to 800 different IP's this month. Let me know if you'd
like more.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

Relevant Pages

  • Re: Why does reading from /dev/urandom deplete entropy so much?
    ... push a Time-based UUID generator into the kernel because you can get ... has been returning duplicates. ... preserve anonymity while allowing system profiles etc to be generated and ...
    (Linux-Kernel)
  • Re: Why does reading from /dev/urandom deplete entropy so much?
    ... the kernel uuid random generator from the random generator in the kernel ... shows abnormal patterns of duplicates. ... I've not heard of *any* claim where the kernel uuid random generator ...
    (Linux-Kernel)
  • Re: Concurrent access to /dev/urandom
    ... I wrote my own "version-4" UUID generator that reads ... This test does not represent the typical usage of my UUID ... I get duplicates so quickly that I am very concerned ... I will also try your patch. ...
    (Linux-Kernel)
  • Re: Concurrent access to /dev/urandom
    ... In which version of 2.6 did this bug get fixed? ... I am just trying to generate UUIDs (without duplicates, ... > be fixed in the kernel, but if you need to worry about this from the ... send the line "unsubscribe linux-kernel" in ...
    (Linux-Kernel)
  • Re: [RFC] Splitting kernel headers and deprecating __KERNEL__
    ... > You mean it can't break anything in a kernel build, ... > anything except for userland apps that abused kernel headers and used ... > will no longer have to maintain the duplicates. ... send the line "unsubscribe linux-kernel" in ...
    (Linux-Kernel)
Loading