Paul Hoffman wrote:
At 10:25 AM +0100 5/15/08, Ben Laurie wrote:
Paul Hoffman wrote:
I'm confused about two statements here:
At 2:10 PM +0100 5/13/08, Ben Laurie wrote:
The result of this is that for the last two years (from Debian's
"Edgy" release until now), anyone doing pretty much any crypto on
Debian (and hence Ubuntu) has been using easily guessable keys. This
includes SSH keys, SSL keys and OpenVPN keys.
. . .
[2] Valgrind tracks the use of uninitialised memory. Usually it is
bad to have any kind of dependency on uninitialised memory, but
OpenSSL happens to include a rare case when its OK, or even a good
idea: its randomness pool. Adding uninitialised memory to it can do
no harm and might do some good, which is why we do it. It does cause
irritating errors from some kinds of debugging tools, though,
including valgrind and Purify. For that reason, we do have a flag
(PURIFY) that removes the offending code. However, the Debian
maintainers, instead of tracking down the source of the
uninitialised memory instead chose to remove any possibility of
adding memory to the pool at all. Clearly they had not understood
the bug before fixing it.
The second bit makes it sound like the stuff that the Debian folks
blindly removed was one, possibly-useful addition to the entropy
pool. The first bit makes it sound like the stuff was absolutely
critical to the entropy of produced keys. Which one is correct?
They removed _all_ entropy addition to the pool, with the exception of
the PID, which is mixed in at a lower level.
I take it that these are not 128-bit, non-monotonic PIDs. :-)
The bigger picture is that distributions who are doing local mods should
really have an ongoing conversation with the software's developers. Even
if the developers don't want to talk to you, a one-way conversation of
"we're doing this, we're doing that" could be useful.
That doesn't scale very well, though - which is why my position is that
they should avoid local mods.
--
http://www.apache-ssl.org/ben.html http://www.links.org/
"There is no limit to what a man can do or how far he can go if he
doesn't mind who gets the credit." - Robert Woodruff
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