exactly the same functionality via a sysctl, making this feature
a run-time option.
The default is 1(ON), which means that /dev/random device will
NOT block at startup.
setting kern.random.sys.seeded to 0(OFF) will cause /dev/random
to block until the next reseed, at which stage the sysctl
will be changed back to 1(ON).
While I'm here, clean up the sysctls, and make them dynamic.
Reviewed by: des
Tested on Alpha by: obrien
There is no more TAILQ fifo to harvest the entropy; instead, there
is a circular buffer of constant size (changeable by macro) that
pretty dramatically improves the speed and fixes potential slowdowns-
by-locking.
Also gone are a slew of malloc(9) and free(9) calls; all harvesting
buffers are static.
All-in-all, this is a good performance improvement.
Thanks-to: msmith for the circular buffer concept-code.
call instead.
This makes a pretty dramatic difference to the amount of work that
the harvester needs to do - it is much friendlier on the system.
(80386 and 80486 class machines will notice little, as the new
get_cyclecounter() call is a wrapper round nanotime(9) for them).
<sys/proc.h> to <sys/systm.h>.
Correctly document the #includes needed in the manpage.
Add one now needed #include of <sys/systm.h>.
Remove the consequent 48 unused #includes of <sys/proc.h>.
priority "0" and without PCATCH, so it was uninterruptable. And
even when it did wake up after entropy arrived, it exited after the
wakeup without actually reading the freshly arrived entropy. I
sent this to Mark before but it seems he is in transit.
Mark: feel free to replace this if it gets in your way.
now in dirs called sys/*/random/ instead of sys/*/randomdev/*.
Introduce blocking, but only at startup; the random device will
block until the first reseed happens to prevent clients from
using untrustworthy output.
Provide a read_random() call for the rest of the kernel so that
the entropy device does not need to be present. This means that
things like IPX no longer need to have "device random" hardcoded
into thir kernel config. The downside is that read_random() will
provide very poor output until the entropy device is loaded and
reseeded. It is recommended that developers do NOT use the
read_random() call; instead, they should use arc4random() which
internally uses read_random().
Clean up the mutex and locking code a bit; this makes it possible
to unload the module again.
hangover from previous experimentation. Remove it. This will clean
up gratuitous needs for forward references and other namespace
pollution.
Moaned about by: bde
Brought to my attention by: bp
from many folk.
o The reseed process is now a kthread. With SMPng, kthreads are
pre-emptive, so the annoying jerkiness of the mouse is gone.
o The data structures are protected by mutexes now, not splfoo()/splx().
o The cryptographic routines are broken out into their own subroutines.
this facilitates review, and possible replacement if that is ever
found necessary.
Thanks to: kris, green, peter, jasone, grog, jhb
Forgotten to thank: You know who you are; no offense intended.
wrong bytes.
o Improve the public interface; use void* instead of char* or u_int64_t
to pass arbitrary data around.
Submitted by: kris ("horrible bug")
o Make the comments KNF-compliant.
o Use nanotime instead of getnanotime; the manpage lies about the
kern.timecounter.method - it has been removed.
o Fix the ENTROPYSOURCE const permanently.
o Make variable names more consistent.
o Make function prototypes more consistent.
Some more needs to be done; to follow.
entropy estimation, but causes an immediate reseed after the input
(read in sizeof(u_int64_t) chunks) is "harvested".
This will be used in the reboot "reseeder", coming in another
commit. This can be used very effectively at any time you think
your randomness is compromised; something like
# (ps -gauxwww; netstat -an; dmesg; vmstat -c10 1) > /dev/random
will give the attacker something to think about.
with splhigh(). However, the entropy-harvesting routine needs pretty
serious irq-protection, as it is called out of irq handlers etc.
Clues given by: bde
structure; remind myself in the cooments. Also regroup all the Yarrow
variables at the top of the variable list; they are "special".
(no functional change).
stack. It's bad for your machine's health.
Make the two huge structs in reseed() static to prevent crashes. This
is the bug that people have been running into and panic()ing on for the
past few days.
Reviewed by: phk
device with Yarrow, and although I coded for that in dev/MAKEDEV, I forgot
to _tell_ folks.
This commit adds back the /dev/urandom device (as a duplicate) of /dev/random,
until such time as it can be properly announced.
This will help the openssl users quite a lot.
This is work-in-progress, and the entropy-gathering routines are not
yet present. As such, this should be viewed as a pretty reasonable
PRNG with _ABSOLUTELY_NO_ security!!
Entropy gathering will be the subject of ongoing work.
This is written as a module, and as such is unloadable, but there is
no refcounting done. I would like to use something like device_busy(9)
to achieve this (eventually).
Lots of useful ideas from: bde, phk, Jeroen van Gelderen
Reviewed by: dfr
