random script ran before filesystems were mounted, which is no
longer the case.
In random_start(), immediately delete each file that is fed into
/dev/random, and recreate the default entropy file immediately
after reading and deleting it. The logic used in random_stop()
to determine which file to write to should probably be factored
out and used here as well.
This code has had an extensive rewrite and a good series of reviews, both by the author and other parties. This means a lot of code has been simplified. Pluggable structures for high-rate entropy generators are available, and it is most definitely not the case that /dev/random can be driven by only a hardware souce any more. This has been designed out of the device. Hardware sources are stirred into the CSPRNG (Yarrow, Fortuna) like any other entropy source. Pluggable modules may be written by third parties for additional sources.
The harvesting structures and consequently the locking have been simplified. Entropy harvesting is done in a more general way (the documentation for this will follow). There is some GREAT entropy to be had in the UMA allocator, but it is disabled for now as messing with that is likely to annoy many people.
The venerable (but effective) Yarrow algorithm, which is no longer supported by its authors now has an alternative, Fortuna. For now, Yarrow is retained as the default algorithm, but this may be changed using a kernel option. It is intended to make Fortuna the default algorithm for 11.0. Interested parties are encouraged to read ISBN 978-0-470-47424-2 "Cryptography Engineering" By Ferguson, Schneier and Kohno for Fortuna's gory details. Heck, read it anyway.
Many thanks to Arthur Mesh who did early grunt work, and who got caught in the crossfire rather more than he deserved to.
My thanks also to folks who helped me thresh this out on whiteboards and in the odd "Hallway track", or otherwise.
My Nomex pants are on. Let the feedback commence!
Reviewed by: trasz,des(partial),imp(partial?),rwatson(partial?)
Approved by: so(des)
systems are fully "ready to go".
'FILESYSTEMS' states: "This is a dummy dependency, for services which
require file systems to be mounted before starting." However, we have
'var' which is was run after 'FILESYSTEMS' and can mount /var if it
already isn't mounted. Furthermore, several scripts cannot use /var
until 'cleanvar' has done its thing. Thus "FILESYSTEMS" hasn't really
meant all critical file systems are fully usable.
Include /var/db/entropy-file in the reseeding if present. It is used for
last-ditch efforts to save entropy and thus should also be used to seed
the RNG when starting. Print a warning instead of an error if writing the
file fails -- err() exits, preventing the umask from being restored.
Also, since there's not much that can be done about it, notifying the user
is all that's needed.
MFC after: 2 weeks
save file was /var/db/entropy, which also happens to
be the directory where the individual entropy files
created by /usr/libexec/save-entropy are stored.
Change the suggestion to be /var/db/entropy-file
instead.
In an error condition where the shutdown file is not
created, the error message accessed a variable that
doesn't exist.
PR: conf/75722
Submitted by: Nicolas Rachinsky <list@rachinsky.de>
* Space -> tabs conversion.
* Removed blanks before semicolon in "if ... ; then".
* Proper indentation of misindented lines.
* Put a full stop after some comments.
* Removed whitespace at end of line.
Approved by: silence from gordon
while. This is only the script pieces, the glue for the build comes next.
Submitted by: Mike Makonnen <makonnen@pacbell.net>
Reviewed by: silence on -current and -hackers
Prodded by: rwatson
