- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Merge from project branch via main. Uninteresting commits are trimmed.

Refactor of /dev/random device. Main points include:

* Userland seeding is no longer used. This auto-seeds at boot time
on PC/Desktop setups; this may need some tweeking and intelligence
from those folks setting up embedded boxes, but the work is believed
to be minimal.

* An entropy cache is written to /entropy (even during installation)
and the kernel uses this at next boot.

* An entropy file written to /boot/entropy can be loaded by loader(8)

* Hardware sources such as rdrand are fed into Yarrow, and are no
longer available raw.

------------------------------------------------------------------------
r256240 | des | 2013-10-09 21:14:16 +0100 (Wed, 09 Oct 2013) | 4 lines

Add a RANDOM_RWFILE option and hide the entropy cache code behind it.
Rename YARROW_RNG and FORTUNA_RNG to RANDOM_YARROW and RANDOM_FORTUNA.
Add the RANDOM_* options to LINT.

------------------------------------------------------------------------
r256239 | des | 2013-10-09 21:12:59 +0100 (Wed, 09 Oct 2013) | 2 lines

Define RANDOM_PURE_RNDTEST for rndtest(4).

------------------------------------------------------------------------
r256204 | des | 2013-10-09 18:51:38 +0100 (Wed, 09 Oct 2013) | 2 lines

staticize struct random_hardware_source

------------------------------------------------------------------------
r256203 | markm | 2013-10-09 18:50:36 +0100 (Wed, 09 Oct 2013) | 2 lines

Wrap some policy-rich code in 'if NOTYET' until we can thresh out
what it really needs to do.

------------------------------------------------------------------------
r256184 | des | 2013-10-09 10:13:12 +0100 (Wed, 09 Oct 2013) | 2 lines

Re-add /dev/urandom for compatibility purposes.

------------------------------------------------------------------------
r256182 | des | 2013-10-09 10:11:14 +0100 (Wed, 09 Oct 2013) | 3 lines

Add missing include guards and move the existing ones out of the
implementation namespace.

------------------------------------------------------------------------
r256168 | markm | 2013-10-08 23:14:07 +0100 (Tue, 08 Oct 2013) | 10 lines

Fix some just-noticed problems:

o Allow this to work with "nodevice random" by fixing where the
MALLOC pool is defined.

o Fix the explicit reseed code. This was correct as submitted, but
in the project branch doesn't need to set the "seeded" bit as this
is done correctly in the "unblock" function.

o Remove some debug ifdeffing.

o Adjust comments.

------------------------------------------------------------------------
r256159 | markm | 2013-10-08 19:48:11 +0100 (Tue, 08 Oct 2013) | 6 lines

Time to eat crow for me.

I replaced the sx_* locks that Arthur used with regular mutexes;
this turned out the be the wrong thing to do as the locks need to
be sleepable. Revert this folly.

# Submitted by: Arthur Mesh <arthurmesh@gmail.com> (In original diff)

------------------------------------------------------------------------
r256138 | des | 2013-10-08 12:05:26 +0100 (Tue, 08 Oct 2013) | 10 lines

Add YARROW_RNG and FORTUNA_RNG to sys/conf/options.

Add a SYSINIT that forces a reseed during proc0 setup, which happens
fairly late in the boot process.

Add a RANDOM_DEBUG option which enables some debugging printf()s.

Add a new RANDOM_ATTACH entropy source which harvests entropy from the
get_cyclecount() delta across each call to a device attach method.

------------------------------------------------------------------------
r256135 | markm | 2013-10-08 07:54:52 +0100 (Tue, 08 Oct 2013) | 8 lines

Debugging. My attempt at EVENTHANDLER(multiuser) was a failure; use
EVENTHANDLER(mountroot) instead.

This means we can't count on /var being present, so something will
need to be done about harvesting /var/db/entropy/... .

Some policy now needs to be sorted out, and a pre-sync cache needs
to be written, but apart from that we are now ready to go.

Over to review.

------------------------------------------------------------------------
r256094 | markm | 2013-10-06 23:45:02 +0100 (Sun, 06 Oct 2013) | 8 lines

Snapshot.

Looking pretty good; this mostly works now. New code includes:

* Read cached entropy at startup, both from files and from loader(8)
preloaded entropy. Failures are soft, but announced. Untested.

* Use EVENTHANDLER to do above just before we go multiuser. Untested.

------------------------------------------------------------------------
r256088 | markm | 2013-10-06 14:01:42 +0100 (Sun, 06 Oct 2013) | 2 lines

Fix up the man page for random(4). This mainly removes no-longer-relevant
details about HW RNGs, reseeding explicitly and user-supplied
entropy.

------------------------------------------------------------------------
r256087 | markm | 2013-10-06 13:43:42 +0100 (Sun, 06 Oct 2013) | 6 lines

As userland writing to /dev/random is no more, remove the "better
than nothing" bootstrap mode.

Add SWI harvesting to the mix.

My box seeds Yarrow by itself in a few seconds! YMMV; more to follow.

------------------------------------------------------------------------
r256086 | markm | 2013-10-06 13:40:32 +0100 (Sun, 06 Oct 2013) | 11 lines

Debug run. This now works, except that the "live" sources haven't
been tested. With all sources turned on, this unlocks itself in
a couple of seconds! That is no my box, and there is no guarantee
that this will be the case everywhere.

* Cut debug prints.

* Use the same locks/mutexes all the way through.

* Be a tad more conservative about entropy estimates.

------------------------------------------------------------------------
r256084 | markm | 2013-10-06 13:35:29 +0100 (Sun, 06 Oct 2013) | 5 lines

Don't use the "real" assembler mnemonics; older compilers may not
understand them (like when building CURRENT on 9.x).

# Submitted by: Konstantin Belousov <kostikbel@gmail.com>

------------------------------------------------------------------------
r256081 | markm | 2013-10-06 10:55:28 +0100 (Sun, 06 Oct 2013) | 12 lines

SNAPSHOT.

Simplify the malloc pools; We only need one for this device.

Simplify the harvest queue.

Marginally improve the entropy pool hashing, making it a bit faster
in the process.

Connect up the hardware "live" source harvesting. This is simplistic
for now, and will need to be made rate-adaptive.

All of the above passes a compile test but needs to be debugged.

------------------------------------------------------------------------
r256042 | markm | 2013-10-04 07:55:06 +0100 (Fri, 04 Oct 2013) | 25 lines

Snapshot. This passes the build test, but has not yet been finished or debugged.

Contains:

* Refactor the hardware RNG CPU instruction sources to feed into
the software mixer. This is unfinished. The actual harvesting needs
to be sorted out. Modified by me (see below).

* Remove 'frac' parameter from random_harvest(). This was never
used and adds extra code for no good reason.

* Remove device write entropy harvesting. This provided a weak
attack vector, was not very good at bootstrapping the device. To
follow will be a replacement explicit reseed knob.

* Separate out all the RANDOM_PURE sources into separate harvest
entities. This adds some secuity in the case where more than one
is present.

* Review all the code and fix anything obviously messy or inconsistent.
Address som review concerns while I'm here, like rename the pseudo-rng
to 'dummy'.

# Submitted by: Arthur Mesh <arthurmesh@gmail.com> (the first item)

------------------------------------------------------------------------
r255319 | markm | 2013-09-06 18:51:52 +0100 (Fri, 06 Sep 2013) | 4 lines

Yarrow wants entropy estimations to be conservative; the usual idea
is that if you are certain you have N bits of entropy, you declare
N/2.

------------------------------------------------------------------------
r255075 | markm | 2013-08-30 18:47:53 +0100 (Fri, 30 Aug 2013) | 4 lines

Remove short-lived idea; thread to harvest (eg) RDRAND enropy into the
usual harvest queues. It was a nifty idea, but too heavyweight.

# Submitted by: Arthur Mesh <arthurmesh@gmail.com>

------------------------------------------------------------------------
r255071 | markm | 2013-08-30 12:42:57 +0100 (Fri, 30 Aug 2013) | 4 lines

Separate out the Software RNG entropy harvesting queue and thread
into its own files.

# Submitted by: Arthur Mesh <arthurmesh@gmail.com>

------------------------------------------------------------------------
r254934 | markm | 2013-08-26 20:07:03 +0100 (Mon, 26 Aug 2013) | 2 lines

Remove the short-lived namei experiment.

------------------------------------------------------------------------
r254928 | markm | 2013-08-26 19:35:21 +0100 (Mon, 26 Aug 2013) | 2 lines

Snapshot; Do some running repairs on entropy harvesting. More needs
to follow.

------------------------------------------------------------------------
r254927 | markm | 2013-08-26 19:29:51 +0100 (Mon, 26 Aug 2013) | 15 lines

Snapshot of current work;

1) Clean up namespace; only use "Yarrow" where it is Yarrow-specific
or close enough to the Yarrow algorithm. For the rest use a neutral
name.

2) Tidy up headers; put private stuff in private places. More could
be done here.

3) Streamline the hashing/encryption; no need for a 256-bit counter;
128 bits will last for long enough.

There are bits of debug code lying around; these will be removed
at a later stage.

------------------------------------------------------------------------
r254784 | markm | 2013-08-24 14:54:56 +0100 (Sat, 24 Aug 2013) | 39 lines

1) example (partially humorous random_adaptor, that I call "EXAMPLE")
* It's not meant to be used in a real system, it's there to show how
the basics of how to create interfaces for random_adaptors. Perhaps
it should belong in a manual page

2) Move probe.c's functionality in to random_adaptors.c
* rename random_ident_hardware() to random_adaptor_choose()

3) Introduce a new way to choose (or select) random_adaptors via tunable
"rngs_want" It's a list of comma separated names of adaptors, ordered
by preferences. I.e.:
rngs_want="yarrow,rdrand"

Such setting would cause yarrow to be preferred to rdrand. If neither of
them are available (or registered), then system will default to
something reasonable (currently yarrow). If yarrow is not present, then
we fall back to the adaptor that's first on the list of registered
adaptors.

4) Introduce a way where RNGs can play a role of entropy source. This is
mostly useful for HW rngs.

The way I envision this is that every HW RNG will use this
functionality by default. Functionality to disable this is also present.
I have an example of how to use this in random_adaptor_example.c (see
modload event, and init function)

5) fix kern.random.adaptors from
kern.random.adaptors: yarrowpanicblock
to
kern.random.adaptors: yarrow,panic,block

6) add kern.random.active_adaptor to indicate currently selected
adaptor:
root@freebsd04:~ # sysctl kern.random.active_adaptor
kern.random.active_adaptor: yarrow

# Submitted by: Arthur Mesh <arthurmesh@gmail.com>

Submitted by: Dag-Erling Smørgrav <des@FreeBSD.org>, Arthur Mesh <arthurmesh@gmail.com>
Reviewed by: des@FreeBSD.org
Approved by: re (delphij)
Approved by: secteam (des,delphij)

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Fix the build; Certain linkable symbols need to always be present.

Pass the pointy hat please.

Also unblock the software (Yarrow) generator for now. This will be
reverted; Yarrow needs to block until secure, not this behaviour
of serving as soon as asked.

Folks with specific requiremnts will be able to (can!) unblock this
device with any write, and are encouraged to do so in /etc/rc.d/*
scripting. ("Any" in this case could be "echo '' > /dev/random" as
root).

Bring in some behind-the-scenes development, mainly By Arthur Mesh,
the rest by me.

o Namespace cleanup; the Yarrow name is now restricted to where it
really applies; this is in anticipation of being augmented or
replaced by Fortuna in the future. Fortuna is mentioned, but behind
#if logic, and is ignorable for now.

o The harvest queue is pulled out into its own modules.

o Entropy harvesting is emproved, both by being made more conservative,
and by separating (a bit!) the sources. Available entropy crumbs are
marginally improved.

o Selection of sources is made clearer. With recent revelations,
this will receive more work in the weeks and months to come.

Submitted by: Arthur Mesh (partly) <arthurmesh@gmail.com>

* Add random_adaptors.[ch] which is basically a store of random_adaptor's.
random_adaptor is basically an adapter that plugs in to random(4).
random_adaptor can only be plugged in to random(4) very early in bootup.
Unplugging random_adaptor from random(4) is not supported, and is probably a
bad idea anyway, due to potential loss of entropy pools.
We currently have 3 random_adaptors:
+ yarrow
+ rdrand (ivy.c)
+ nehemeiah

* Remove platform dependent logic from probe.c, and move it into
corresponding registration routines of each random_adaptor provider.
probe.c doesn't do anything other than picking a specific random_adaptor
from a list of registered ones.

* If the kernel doesn't have any random_adaptor adapters present then the
creation of /dev/random is postponed until next random_adaptor is kldload'ed.

* Fix randomdev_soft.c to refer to its own random_adaptor, instead of a
system wide one.

Submitted by: arthurmesh@gmail.com, obrien
Obtained from: Juniper Networks
Reviewed by: so (des)

Back out r253779 & r253786.

Decouple yarrow from random(4) device.

* Make Yarrow an optional kernel component -- enabled by "YARROW_RNG" option.
The files sha2.c, hash.c, randomdev_soft.c and yarrow.c comprise yarrow.

* random(4) device doesn't really depend on rijndael-*. Yarrow, however, does.

* Add random_adaptors.[ch] which is basically a store of random_adaptor's.
random_adaptor is basically an adapter that plugs in to random(4).
random_adaptor can only be plugged in to random(4) very early in bootup.
Unplugging random_adaptor from random(4) is not supported, and is probably a
bad idea anyway, due to potential loss of entropy pools.
We currently have 3 random_adaptors:
+ yarrow
+ rdrand (ivy.c)
+ nehemeiah

* Remove platform dependent logic from probe.c, and move it into
corresponding registration routines of each random_adaptor provider.
probe.c doesn't do anything other than picking a specific random_adaptor
from a list of registered ones.

* If the kernel doesn't have any random_adaptor adapters present then the
creation of /dev/random is postponed until next random_adaptor is kldload'ed.

* Fix randomdev_soft.c to refer to its own random_adaptor, instead of a
system wide one.

Submitted by: arthurmesh@gmail.com, obrien
Obtained from: Juniper Networks
Reviewed by: obrien

Refactor random_systat to be a *random_systat. This avoids unnecessary
structure copying in random_ident_hardware(). This change will also help
further modularization of random(4) subsystem.

Submitted by: arthurmesh@gmail.com
Reviewed by: obrien
Obtained from: Juniper Networks

Finish r210923, 210926. Mark some devices as eternal.

MFC after: 2 weeks

Make sure arc4random(9) is properly seeded when /etc/rc.d/initrandom returns.

Approved by: so (cperciva)
Approved by: re (kensmith)
Security: FreeBSD-SA-08:11.arc4random

Sweep kernel replacing suser(9) calls with priv(9) calls, assigning
specific privilege names to a broad range of privileges. These may
require some future tweaking.

Sponsored by: nCircle Network Security, Inc.
Obtained from: TrustedBSD Project
Discussed on: arch@
Reviewed (at least in part) by: mlaier, jmg, pjd, bde, ceri,
Alex Lyashkov <umka at sevcity dot net>,
Skip Ford <skip dot ford at verizon dot net>,
Antoine Brodin <antoine dot brodin at laposte dot net>

Remove GIANT from device random.

Submitted by: ups

Check O_NONBLOCK not IO_NDELAY.

Don't include vnode.h

Add module versions.

Start the entropy device insecure/unblocked. I'll be handing over
responsibility for critical randomness requirements (like sshd)
to rc.d/*

Requested by: many

Do a pass over all modules in the kernel and make them return EOPNOTSUPP
for unknown events.

A number of modules return EINVAL in this instance, and I have left
those alone for now and instead taught MOD_QUIESCE to accept this
as "didn't do anything".

Trim a few things from the dmesg output and stick them under bootverbose to
cut down on the clutter including PCI interrupt routing, MTRR, pcibios,
etc.

Discussed with: USENIX Cabal

Do the dreaded s/dev_t/struct cdev */
Bump __FreeBSD_version accordingly.

Add some missing <sys/module.h> includes which are masked by the
one on death-row in <sys/kernel.h>

More removal of the abortive locking code; malloc buffers when
needed, rather than potentially reusing contents.

Attempts to make this device Giant-free were ill-conceived as
uiomove(9) is not properly locked. So, return to NEEDGIANT
mode. Later, when uiomove is finely locked, I'll revisit.

While I'm here, provide some temporary debugging output to
help catch blocking startups.

Fix "sleeping without a mutex" panic.

Reorganise the entropy device so that high-yield entropy sources
can more easily be used INSTEAD OF the hard-working Yarrow.
The only hardware source used at this point is the one inside
the VIA C3 Nehemiah (Stepping 3 and above) CPU. More sources will
be added in due course. Contributions welcome!

Device megapatch 4/6:

Introduce d_version field in struct cdevsw, this must always be
initialized to D_VERSION.

Flip sense of D_NOGIANT flag to D_NEEDGIANT, this involves removing
four D_NOGIANT flags and adding 145 D_NEEDGIANT flags.

Correct the cleanup of the alias dev_t for /dev/urandom: being an
alias it depends on the aliased dev_t and disappears automatically
when that is removed.

Submitted by: "Bjoern A. Zeeb" <bzeeb+freebsd@zabbadoz.net>

Fix a major faux pas of mine. I was causing 2 very bad things to
happen in interrupt context; 1) sleep locks, and 2) malloc/free
calls.

1) is fixed by using spin locks instead.

2) is fixed by preallocating a FIFO (implemented with a STAILQ)
and using elements from this FIFO instead. This turns out
to be rather fast.

OK'ed by: re (scottl)
Thanks to: peter, jhb, rwatson, jake
Apologies to: *

Overhaul the entropy device:

o Each source gets its own queue, which is a FIFO, not a ring buffer.
The FIFOs are implemented with the sys/queue.h macros. The separation
is so that a low entropy/high rate source can't swamp the harvester
with low-grade entropy and destroy the reseeds.

o Each FIFO is limited to 256 (set as a macro, so adjustable) events
queueable. Full FIFOs are ignored by the harvester. This is to
prevent memory wastage, and helps to keep the kernel thread CPU
usage within reasonable limits.

o There is no need to break up the event harvesting into ${burst}
sized chunks, so retire that feature.

o Break the device away from its roots with the memory device, and
allow it to get its major number automagically.

- Implement selwakeuppri() which allows raising the priority of a
thread being waken up. The thread waken up can run at a priority as
high as after tsleep().

- Replace selwakeup()s with selwakeuppri()s and pass appropriate
priorities.

- Add cv_broadcastpri() which raises the priority of the broadcast
threads. Used by selwakeuppri() if collision occurs.

Not objected in: -arch, -current

Make sure we get all user-written input. This simplifies the
code considerably.

Submitted by: (forgotten)
[I'll happily acknowledge the submitter if he owns up!]

Use __FBSDID().
Also some minor style cleanups.

Change the sleep identifier to "-" where random normally sleeps.

Gigacommit to improve device-driver source compatibility between
branches:

Initialize struct cdevsw using C99 sparse initializtion and remove
all initializations to default values.

This patch is automatically generated and has been tested by compiling
LINT with all the fields in struct cdevsw in reverse order on alpha,
sparc64 and i386.

Approved by: re(scottl)

Back out M_* changes, per decision of the TRB.

Approved by: trb

Remove M_TRYWAIT/M_WAITOK/M_WAIT. Callers should use 0.
Merge M_NOWAIT/M_DONTWAIT into a single flag M_NOWAIT.

Some kernel threads try to do significant work, and the default KSTACK_PAGES
doesn't give them enough stack to do much before blowing away the pcb.
This adds MI and MD code to allow the allocation of an alternate kstack
who's size can be speficied when calling kthread_create. Passing the
value 0 prevents the alternate kstack from being created. Note that the
ia64 MD code is missing for now, and PowerPC was only partially written
due to the pmap.c being incomplete there.
Though this patch does not modify anything to make use of the alternate
kstack, acpi and usb are good candidates.

Reviewed by: jake, peter, jhb

Remove #ifdef'ed Giant mutex wrappers round debugging statements.

Change the suser() API to take advantage of td_ucred as well as do a
general cleanup of the API. The entire API now consists of two functions
similar to the pre-KSE API. The suser() function takes a thread pointer
as its only argument. The td_ucred member of this thread must be valid
so the only valid thread pointers are curthread and a few kernel threads
such as thread0. The suser_cred() function takes a pointer to a struct
ucred as its first argument and an integer flag as its second argument.
The flag is currently only used for the PRISON_ROOT flag.

Discussed on: smp@

Provide infrastructure for harvesting SWI entropy.

Massive lint-inspired cleanup.

Remove unneeded includes.
Deal with unused function arguments.
Resolve a boatload of signed/unsigned imcompatabilities.
Etc.

Simple p_ucred -> td_ucred changes to start using the per-thread ucred
reference.

o Modify open() and close() for /dev/random to use securelevel_gt() instead
of direct securelevel variable checks.

Obtained from: TrustedBSD Project

Use the passed in thread to selrecord() instead of curthread.

KSE Milestone 2
Note ALL MODULES MUST BE RECOMPILED
make the kernel aware that there are smaller units of scheduling than the
process. (but only allow one thread per process at this time).
This is functionally equivalent to teh previousl -current except
that there is a thread associated with each process.

Sorry john! (your next MFC will be a doosie!)

Reviewed by: peter@freebsd.org, dillon@freebsd.org

X-MFC after: ha ha ha ha

Undo part of the tangle of having sys/lock.h and sys/mutex.h included in
other "system" header files.

Also help the deprecation of lockmgr.h by making it a sub-include of
sys/lock.h and removing sys/lockmgr.h form kernel .c files.

Sort sys/*.h includes where possible in affected files.

OK'ed by: bde (with reservations)

Send the remains (such as I have located) of "block major numbers" to
the bit-bucket.

I need to add to the previous commit:

Tested by: dougb

Allow bog-standard ioctls through. There are really handled in
higher layers, but there needs to be a "no-error" return here.

Very large makeover of the /dev/random driver.

o Separate the kernel stuff from the Yarrow algorithm. Yarrow is now
well contained in one source file and one header.

o Replace the Blowfish-based crypto routines with Rijndael-based ones.
(Rijndael is the new AES algorithm). The huge improvement in
Rijndael's key-agility over Blowfish means that this is an
extremely dramatic improvement in speed, and makes a heck of
a difference in its (lack of) CPU load.

o Clean up the sysctl's. At BDE's prompting, I have gone back to
static sysctls.

o Bug fixes. The streamlining of the crypto stuff enabled me to
find and fix some bugs. DES also found a bug in the reseed routine
which is fixed.

o Change the way reseeds clear "used" entropy. Previously, only the
source(s) that caused a reseed were cleared. Now all sources in the
relevant pool(s) are cleared.

o Code tidy-up. Mostly to make it (nearly) 80-column compliant.

Provide the infrastructure for sysadmins to select the broad class
of entropy harvesting they wish to perform: "ethernet" (LAN),
point-to-point and interrupt.

Remove NOBLOCKRANDOM as a compile-time option. Instead, provide
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

select() DKI is now in <sys/selinfo.h>.

D'uh. The explicit reseed was happening at the wrong security/privelige
levels.

Greatly improve the boot-up unblocking time of the entropy device.

Move suser() and suser_xxx() prototypes and a related #define from
<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>.

As the blocking model has seems to be troublesome for many, disable
it for now with an option.

This option is already deprecated, and will be removed when the
entropy-harvesting code is fast enough to warrant it.

Attempt to fix the random read blocking. The old code slept at
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.

After some complaints about the dir names, the random device is
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.

Remove unneeded includes.

Submitted by: phk

Include <sys/proc.h> to silence suser() compiler warning.

Approved by: markm

The "struct proc" argument to read_random was ill-conceived, and a
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

Large upgrade to the entropy device; mainly inspired by feedback
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.

Forgot from last commit:

o if the device is being written to, and the user is not root, or
the securelevel is greater than 0, then fail with EPERM.

o Fix a horrible bug where small reads (< 8 bytes) would return the
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")

Add randomness write functionality. This does absolutely nothing for
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.

Fix bug with a vraiable that needs to be per-process, not static;
fix formatting of long macros.

Pointed out by: bde

Add entropy gathering code. This will work whether the module is
compiled in or loaded.

Staticize a variable.

This fixes the case where linking randomdev into the kernel statically
can cause panics at shutdown time.

Reported by: sos

I am guilty of an act of ommission. There is no longer a /dev/urandom
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.

style(9) fixes from BDE.
We shouldn't use '#include ""', rather '#include<>'.

Fix include for the non-module case.

Thanks-to: SOS

New machine-independant /dev/random driver.

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