MFC r345438,r345842,r346259,r346261: TPM as possible entropy source

r345438:
Allow using TPM as entropy source

TPM has a built-in RNG, with its own entropy source.
The driver was extended to harvest 16 random bytes from TPM every 10 seconds.
A new build option "TPM_HARVEST" was introduced - for now, however, it
is not enabled by default in the GENERIC config.

Reviewed by: markm, delphij
Approved by: secteam

r345842:
Add a cv_wait to the TPM2.0 harvesting function

r346259:
tpm: Prevent session hijack

r346261:
Improve tpm20 style

Submitted by: Kornel Duleba <mindal@semihalf.com>
Obtained from: Semihalf
Sponsored by: Stormshield

Backport fixes from FreeBSD-12 to help the random(4) device thread
not overwhelm the OS:

a) Use the correct symbolic constant when calculating 10'ths of a
second. This means that expensive reseeds happen at ony 1/10 Hz,
not some kHz.

b) Rate limit internal high-rate harveting efforts. This stops the
harvesting thread from total overkilling the high-grade entropy-
gathering work, while still being very conservatively safe.

PR: 230808
Reported by: danilo,eugen
Tested by: eugen
Approved by: so (blanket permission granted as I am the authour of this code)
Relnotes: Yes

Partial MFC of r338542:

random(4): Squash non-error timeout code from tsleep(9).

PR: 231181
Submitted by: cem
Reported by: lev
Reviewed by: vangyzen, markm, delphij
Approved by: secteam (delphij)
Differential Revision: https://reviews.freebsd.org/D17049

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

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

Revert previous commit, until issue with sparc64 resolved.

Approved by: so (implicit)

Add a prototype for random_harvest_queue to dev/random/random_harvestq.h
This fixes a warning that occurs in a number of files that use the
random_harvest_queue function.

Differential Revision: https://reviews.freebsd.org/D4229
Submitted by: stevek@juniper.net
Reviewed by: markm
Approved by: so

Don't repeat the the word 'the'

(one manual change to fix grammar)

Confirmed With: db
Approved by: secteam (not really, but this is a comment typo fix)

dev/random: minor spelling fixes in comments.

No functional change.

Reviewed by: markm
Approved by: so

dev/random: use our roundup() macro instead of re-implementing it.

While here also use howmany() macro from sys/param.h
No functional change.

Reviewed by: markm (roundup replacement part)
Approved by: so

Fix rdrand_rng.ko and padlock_rng.ko dependencies, making modules
loadable when not compiled into the kernel.

Approved by: so (delphij)
Sponsored by: The FreeBSD Foundation

Don't start the random harvester process until timers are working.

This is a no-op currently, but in kernels with earlier AP startup, the
random kthread was trying to use timeouts with sleeps before timers are
working. Wait until SI_SUB_KICK_SCHEDULER to start the random kproc.

Reviewed by: delphij, imp, markm
Approved by: so
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D5712

Add missing braces.

Found by: PVS-Studio
Approved by: so (implicit)

Replace sys/crypto/sha2/sha2.c with lib/libmd/sha512c.c

cperciva's libmd implementation is 5-30% faster

The same was done for SHA256 previously in r263218

cperciva's implementation was lacking SHA-384 which I implemented, validated against OpenSSL and the NIST documentation

Extend sbin/md5 to create sha384(1)

Chase dependancies on sys/crypto/sha2/sha2.{c,h} and replace them with sha512{c.c,.h}

Reviewed by: cperciva, des, delphij
Approved by: secteam, bapt (mentor)
MFC after: 2 weeks
Sponsored by: ScaleEngine Inc.
Differential Revision: https://reviews.freebsd.org/D3929

Fix printf-like formats for KASSERT.

Submitted by: jenkins
Approved by: so (/dev/random blanket)

It appears that under some circumstances, like virtualisiation, the
'rdrand' instruction may occasionally not return random numbers, in
spite of looping attempts to do so. The reusult is a KASSERT/panic.

Reluctantly accept this state-of-affairs, but make a noise about it.
if this 'noise' spams the console, it may be time to discontinue
using that source.

This is written in a general way to account for /any/ source that
might not supply random numbers when required.

Submitted by: jkh (report and slightly different fix)
Approved by: so (/dev/random blanket)

Make the UMA harvesting go away completely if not wanted. Default to "not wanted".
Provide and document the RANDOM_ENABLE_UMA option.

Change RANDOM_FAST to RANDOM_UMA to clarify the harvesting.

Remove RANDOM_DEBUG option, replace with SDT probes. These will be of
use to folks measuring the harvesting effect when deciding whether to
use RANDOM_ENABLE_UMA.

Requested by: scottl and others.
Approved by: so (/dev/random blanket)
Differential Revision: https://reviews.freebsd.org/D3197

Add DEV_RANDOM pseudo-option and use it to "include out" random(4)
if desired.

Retire randomdev_none.c and introduce random_infra.c for resident
infrastructure. Completely stub out random(4) calls in the "without
DEV_RANDOM" case.

Add RANDOM_LOADABLE option to allow loadable Yarrow/Fortuna/LocallyWritten
algorithm. Add a skeleton "other" algorithm framework for folks
to add their own processing code. NIST, anyone?

Retire the RANDOM_DUMMY option.

Build modules for Yarrow, Fortuna and "other".

Use atomics for the live entropy rate-tracking.

Convert ints to bools for the 'seeded' logic.

Move _write() function from the algorithm-specific areas to randomdev.c

Get rid of reseed() function - it is unused.

Tidy up the opt_*.h includes.

Update documentation for random(4) modules.

Fix test program (reviewers, please leave this).

Differential Revision: https://reviews.freebsd.org/D3354
Reviewed by: wblock,delphij,jmg,bjk
Approved by: so (/dev/random blanket)

Fix some untidy logic. I committed the wrong local fix; please pass the pointy hat.

Approved by: so (/dev/random blanket)

Remove out-of-date comments.

Approved by: so (/dev/random blanket)

Fix the read blocking so that it is interruptable and slow down the rate of console warning spamming while blocked.

Approved by: so (/dev/random blanket)

Optimise the buffer-size calculation. It was possible to get one block too many.

Approved by: so (/dev/random blanket)

Fix the build after breaking it in r285549.

I performed the commit on a different system as where I wrote the
change. After pulling in the change from Phabricator, I didn't notice
that a single chunk did not apply.

Approved by: secteam (implicit, as intended change was approved)
Pointy hat to: me

Implement the CloudABI random_get() system call.

The random_get() system call works similar to getentropy()/getrandom()
on OpenBSD/Linux. It fills a buffer with random data.

This change introduces a new function, read_random_uio(), that is used
to implement read() on the random devices. We can call into this
function from within the CloudABI compatibility layer.

Approved by: secteam
Reviewed by: jmg, markm, wblock
Obtained from: https://github.com/NuxiNL/freebsd
Differential Revision: https://reviews.freebsd.org/D3053

Rework the read routines to keep the PRNG sources happy. These work
in units of crypto blocks, so must have adequate space to write.
This means needing to be careful about buffers and keeping track
of external read request length.

Approved by: so (/dev/random blanket)

* Address review (and add a bit myself).
- Tweek man page.
- Remove all mention of RANDOM_FORTUNA. If the system owner wants YARROW or DUMMY, they ask for it, otherwise they get FORTUNA.
- Tidy up headers a bit.
- Tidy up declarations a bit.
- Make static in a couple of places where needed.
- Move Yarrow/Fortuna SYSINIT/SYSUNINIT to randomdev.c, moving us towards a single file where the algorithm context is used.
- Get rid of random_*_process_buffer() functions. They were only used in one place each, and are better subsumed into those places.
- Remove *_post_read() functions as they are stubs everywhere.
- Assert against buffer size illegalities.
- Clean up some silly code in the randomdev_read() routine.
- Make the harvesting more consistent.
- Make some requested argument name changes.
- Tidy up and clarify a few comments.
- Make some requested comment changes.
- Make some requested macro changes.

* NOTE: the thing calling itself a 'unit test' is not yet a proper
unit test, but it helps me ensure things work. It may be a proper
unit test at some time in the future, but for now please don't make
any assumptions or hold any expectations.

Differential Revision: https://reviews.freebsd.org/D2025
Approved by: so (/dev/random blanket)

Huge cleanup of random(4) code.

* GENERAL
- Update copyright.
- Make kernel options for RANDOM_YARROW and RANDOM_DUMMY. Set
neither to ON, which means we want Fortuna
- If there is no 'device random' in the kernel, there will be NO
random(4) device in the kernel, and the KERN_ARND sysctl will
return nothing. With RANDOM_DUMMY there will be a random(4) that
always blocks.
- Repair kern.arandom (KERN_ARND sysctl). The old version went
through arc4random(9) and was a bit weird.
- Adjust arc4random stirring a bit - the existing code looks a little
suspect.
- Fix the nasty pre- and post-read overloading by providing explictit
functions to do these tasks.
- Redo read_random(9) so as to duplicate random(4)'s read internals.
This makes it a first-class citizen rather than a hack.
- Move stuff out of locked regions when it does not need to be
there.
- Trim RANDOM_DEBUG printfs. Some are excess to requirement, some
behind boot verbose.
- Use SYSINIT to sequence the startup.
- Fix init/deinit sysctl stuff.
- Make relevant sysctls also tunables.
- Add different harvesting "styles" to allow for different requirements
(direct, queue, fast).
- Add harvesting of FFS atime events. This needs to be checked for
weighing down the FS code.
- Add harvesting of slab allocator events. This needs to be checked for
weighing down the allocator code.
- Fix the random(9) manpage.
- Loadable modules are not present for now. These will be re-engineered
when the dust settles.
- Use macros for locks.
- Fix comments.

* src/share/man/...
- Update the man pages.

* src/etc/...
- The startup/shutdown work is done in D2924.

* src/UPDATING
- Add UPDATING announcement.

* src/sys/dev/random/build.sh
- Add copyright.
- Add libz for unit tests.

* src/sys/dev/random/dummy.c
- Remove; no longer needed. Functionality incorporated into randomdev.*.

* live_entropy_sources.c live_entropy_sources.h
- Remove; content moved.
- move content to randomdev.[ch] and optimise.

* src/sys/dev/random/random_adaptors.c src/sys/dev/random/random_adaptors.h
- Remove; plugability is no longer used. Compile-time algorithm
selection is the way to go.

* src/sys/dev/random/random_harvestq.c src/sys/dev/random/random_harvestq.h
- Add early (re)boot-time randomness caching.

* src/sys/dev/random/randomdev_soft.c src/sys/dev/random/randomdev_soft.h
- Remove; no longer needed.

* src/sys/dev/random/uint128.h
- Provide a fake uint128_t; if a real one ever arrived, we can use
that instead. All that is needed here is N=0, N++, N==0, and some
localised trickery is used to manufacture a 128-bit 0ULLL.

* src/sys/dev/random/unit_test.c src/sys/dev/random/unit_test.h
- Improve unit tests; previously the testing human needed clairvoyance;
now the test will do a basic check of compressibility. Clairvoyant
talent is still a good idea.
- This is still a long way off a proper unit test.

* src/sys/dev/random/fortuna.c src/sys/dev/random/fortuna.h
- Improve messy union to just uint128_t.
- Remove unneeded 'static struct fortuna_start_cache'.
- Tighten up up arithmetic.
- Provide a method to allow eternal junk to be introduced; harden
it against blatant by compress/hashing.
- Assert that locks are held correctly.
- Fix the nasty pre- and post-read overloading by providing explictit
functions to do these tasks.
- Turn into self-sufficient module (no longer requires randomdev_soft.[ch])

* src/sys/dev/random/yarrow.c src/sys/dev/random/yarrow.h
- Improve messy union to just uint128_t.
- Remove unneeded 'staic struct start_cache'.
- Tighten up up arithmetic.
- Provide a method to allow eternal junk to be introduced; harden
it against blatant by compress/hashing.
- Assert that locks are held correctly.
- Fix the nasty pre- and post-read overloading by providing explictit
functions to do these tasks.
- Turn into self-sufficient module (no longer requires randomdev_soft.[ch])
- Fix some magic numbers elsewhere used as FAST and SLOW.

Differential Revision: https://reviews.freebsd.org/D2025
Reviewed by: vsevolod,delphij,rwatson,trasz,jmg
Approved by: so (delphij)

- fortuna.c: catch up with r278927 and fix a buffer overflow by using the
temporary buffer when remaining space is not enough to hold
a whole block.
- yarrow.c: add a comment that we intend to change the code and remove
memcpy's in the future. (*)

Requested by: markm (*)
Reviewed by: markm
Approved by: so (self)

Fix a bug where this function overflowed it's buffer... This was
causing ZFS panics on boot...

This is purely reviewed and tested by peter.

Reviewed by: peter
Approved by: so (implicit), peter

When the new random adaptor code was brought it in r273872, a call to
randomdev_init_reader to change read_random over to the newly installed
adaptor was missed. This means both read_random and arc4random (seeded
from read_random) were not returning very random data. This also
effects userland arc4random as it is seeded from kernel arc4random.

The random devices are uneffected and have returned good randomness
since the change.

All keys generated with a kernel of r273872 must be regenerated with
a kernel with this patch. Keys generated may be predictable.

Remove the warning as log is too early to print anything, and it would
always get printed due to early use of arc4random...

Reviewed by: delphij, markm
Approved by: so (delphij)

Update comment.

Noted by: dim
Approved by: secteam (des)
MFC after: 4 days

Constify the AES code and propagate to consumers. This allows us to
update the Fortuna code to use SHAd-256 as defined in FS&K.

Approved by: so (self)

Fix random.ko module.
- Remove duplicated sources between standard part of the kernel and
module. In particular, it caused duplicated lock initialization and
sysctl registration, both having bad consequences.
- Add missed source files to module.
- Static part of the kernel provides randomdev module, not
random_adaptors. Correct dependencies.
- Use cdev modules declaration macros.

Approved by: secteam (delphij)
Reviewed by: markm

Simplify assembler in ivy.c. Move the copying of the random bits into
buffer from asm to C, which reduces amount of arguments for inline asm
and simplifies constraints. Use unsigned types consistently.

Submitted by: bde
Approved by: secteam (delphij)
Reviewed by: markm
MFC after: 1 week

When reseeding the DPRNG, we're supposed to hash the current key and
some accumulated entropy twice and use that as the new key. Due to a
typo, we were using the output of the first hash round instead of the
second. Correct this, but eliminate temp[] since we can reuse hash[].
Also add comments explaining what is going on and why.

Noticed by: Sami Farin <sami.farin@gmail.com>
Reviewed by: markm@
Approved by: so (des)

Don't assert random_adaptors_lock in random_adaptor_read_rate().

Reported by: many
Pointy hat to: delphij (for not testing the commit with WITNESS)
Approved by: so

- Make sure random_adaptor accesses happen only when
random_adaptors_lock is held.
- Use sx_sleep instead of tsleep in read and write path to allow
another thread that registers a new random adapter when waiting.
Assert that random_adaptor is not NULL after reacquiring the lock.
- Capture EINTR/ERESTART from sx_sleep to allow the blocking cycle be
stopped when user requests so, while there also make short
read/write's return 0.
- Move M_WAITOK allocations out of lock scope.

In collobration with: kib, markm, ian, jilles
Reviewed by: kib, markm
Approved by: so

Restore the auto-reseed logic, but move it to a much later point,
immediately before kick_init.

Approved by: so (self)

This is the much-discussed major upgrade to the random(4) device, known to you all as /dev/random.

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)

Make sure correct object code is generated at -O0.

Submitted by: grehan@
Approved by: so@ (des)
MFC after: 1 month

Use Intel's official name (Secure Key) per Intel® Digital Random Number
Generator (DRNG) Software Implementation Guide.

Reviewed by: kib
Approved by: so
MFC after: 2 weeks

Correctly set the sysctl format to Alphanumeric, rather than letting it default.

Approved by: security-officer(des)

Convert the random entropy harvesting code to use a const void * pointer
rather than just void *.

Then, as part of this, convert a couple of mbuf m->m_data accesses
to mtod(m, const void *).

Reviewed by: markm
Approved by: security-officer (delphij)
Sponsored by: Netflix, Inc.

Utilize the stronger guarantees on the call arguments from the
harvester, which now always calls hwrngs with the buffer length
multiple of the word size. This allows to remove the excessive memory
accesses to temporary buffer when saving the entropy word.

Streamline the assembly and unify it between i386 and amd64.

Reviewed by: markm, des
Approved by: so (des)
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks

There is an issue (not seen in our testing) where "yarrow" and
"dummy" switch priorities, and the users are left with no usable
/dev/random. The fix assigns priories to these and gives the users
what they want. The override tuneable has a stupid name (blame me!)
and this fixes it to be something that 'sysctl kern.random' emits
and is the right thing to set.

Approved by: re (gjb)
Approved by: secteam (cperciva)

Merge from project branch. 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.

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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.

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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.

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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)

Now our binutils's assembler supports the Intel Random Number Generator
extensions, we can change the .byte directives in sys/dev/random/ivy.c
to plain 'rdrand' mnemonics. This already worked for clang users, but
now it will also work for gcc users.

Approved by: re (kib)
Approved by: so (des)
MFC after: 1 week

Fix verbose output line; needs <NL>

Submitted by: Sean Bruno <sean_bruno@yahoo.com>
Approved by: re (glebius)

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

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

Attempt to mitigate poor initialization of arc4 by one-shot
reinitialization from yarrow right after good entropy is harvested.

Approved by: secteam (delphij)
MFC after: 1 week

MFcalloutng (r236314 by mav):
Specify that wakeup rate of 7.5-10Hz is enough for yarrow harvesting
thread.

Sponsored by: Google Summer of Code 2012, iXsystems inc.
Tested by: flo, marius, ian, markj, Fabian Keil

Correct a typo introduced in r153575, which gives inverted logic when
handling blocking semantics when seeding.

PR: kern/143298
Submitted by: James Juran <james juran baesystems com>
Reviewed by: markm
MFC after: 3 days

Rename the IVY_RNG option to RDRAND_RNG.

Based on submission by: Arthur Mesh <arthurmesh@gmail.com>
MFC after: 2 weeks

Add support for new Intel on-CPU Bull Mountain random number
generator, found on IvyBridge and supposedly later CPUs, accessible
with RDRAND instruction.

From the Intel whitepapers and articles about Bull Mountain, it seems
that we do not need to perform post-processing of RDRAND results, like
AES-encryption of the data with random IV and keys, which was done for
Padlock. Intel claims that sanitization is performed in hardware.

Make both Padlock and Bull Mountain random generators support code
covered by kernel config options, for the benefit of people who prefer
minimal kernels. Also add the tunables to disable hardware generator
even if detected.

Reviewed by: markm, secteam (simon)
Tested by: bapt, Michael Moll <kvedulv@kvedulv.de>
MFC after: 3 weeks

Add support for the extended FPU states on amd64, both for native
64bit and 32bit ABIs. As a side-effect, it enables AVX on capable
CPUs.

In particular:

- Query the CPU support for XSAVE, list of the supported extensions
and the required size of FPU save area. The hw.use_xsave tunable is
provided for disabling XSAVE, and hw.xsave_mask may be used to
select the enabled extensions.

- Remove the FPU save area from PCB and dynamically allocate the
(run-time sized) user save area on the top of the kernel stack,
right above the PCB. Reorganize the thread0 PCB initialization to
postpone it after BSP is queried for save area size.

- The dumppcb, stoppcbs and susppcbs now do not carry the FPU state as
well. FPU state is only useful for suspend, where it is saved in
dynamically allocated suspfpusave area.

- Use XSAVE and XRSTOR to save/restore FPU state, if supported and
enabled.

- Define new mcontext_t flag _MC_HASFPXSTATE, indicating that
mcontext_t has a valid pointer to out-of-struct extended FPU
state. Signal handlers are supplied with stack-allocated fpu
state. The sigreturn(2) and setcontext(2) syscall honour the flag,
allowing the signal handlers to inspect and manipilate extended
state in the interrupted context.

- The getcontext(2) never returns extended state, since there is no
place in the fixed-sized mcontext_t to place variable-sized save
area. And, since mcontext_t is embedded into ucontext_t, makes it
impossible to fix in a reasonable way. Instead of extending
getcontext(2) syscall, provide a sysarch(2) facility to query
extended FPU state.

- Add ptrace(2) support for getting and setting extended state; while
there, implement missed PT_I386_{GET,SET}XMMREGS for 32bit binaries.

- Change fpu_kern KPI to not expose struct fpu_kern_ctx layout to
consumers, making it opaque. Internally, struct fpu_kern_ctx now
contains a space for the extended state. Convert in-kernel consumers
of fpu_kern KPI both on i386 and amd64.

First version of the support for AVX was submitted by Tim Bird
<tim.bird am sony com> on behalf of Sony. This version was written
from scratch.

Tested by: pho (previous version), Yamagi Burmeister <lists yamagi org>
MFC after: 1 month

Generate a warning if the kernel's arc4random() is seeded with bogus entropy.

Enable hardware RNG for VIA Nano processors.

PR: kern/163974

Fix typos - remove duplicate "the".

PR: bin/154928
Submitted by: Eitan Adler <lists at eitanadler.com>
MFC after: 3 days

Finish r210923, 210926. Mark some devices as eternal.

MFC after: 2 weeks

Use the fpu_kern_enter() interface to properly separate usermode FPU
context from in-kernel execution of padlock instructions and to handle
spurious FPUDNA exceptions that sometime are raised when doing padlock
calculations.

Globally mark crypto(9) kthread as using FPU.

Reviewed by: pjd
Hardware provided by: Sentex Communications
Tested by: pho
PR: amd64/135014
MFC after: 1 month

There is rubbish here
It is time to take it out
Now it is cleaner

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

Correct a random value disclosure in random(4).

Security: FreeBSD-SA-07:09.random

Rename the kthread_xxx (e.g. kthread_create()) calls
to kproc_xxx as they actually make whole processes.
Thos makes way for us to add REAL kthread_create() and friends
that actually make theads. it turns out that most of these
calls actually end up being moved back to the thread version
when it's added. but we need to make this cosmetic change first.

I'd LOVE to do this rename in 7.0 so that we can eventually MFC the
new kthread_xxx() calls.

Don't save SYSCTL_ADD_*() results in a local variable just to throw them
away; preserve the ones that are needed for further calls in the init
function and ignore the rest entirely.

Found with: Coverity Prevent(tm)
CID: 563

Rather than repeatedly setting and discarding local variable 'o' based
on the return values of various run-time sysctl additions, just ignore
the return value.

Found with: Coverity Prevent(tm)
CID: 562

Use pause() rather than tsleep() on stack variables and function pointers.

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>

Now even more style(9)ish.

Submitted by: pjd

Use the already stored VIA RNG probe information
instead of probing again.
Adjust style(9) somewhat in probe.c

Reviewed by: pjd
MFC after: 1 week

Use the already stored VIA RNG probe information
instead of probing again.

MFC after: 1 week

Change msleep() and tsleep() to not alter the calling thread's priority
if the specified priority is zero. This avoids a race where the calling
thread could read a snapshot of it's current priority, then a different
thread could change the first thread's priority, then the original thread
would call sched_prio() inside msleep() undoing the change made by the
second thread. I used a priority of zero as no thread that calls msleep()
or tsleep() should be specifying a priority of zero anyway.

The various places that passed 'curthread->td_priority' or some variant
as the priority now pass 0.

Remove GIANT from device random.

Submitted by: ups

malloc.h relies on param.h for a definition of MAXCPU. I guess that there is
other header pollution that makes this work right now, but it falls over when
doing a RELENG_5 -> HEAD upgrade.

Revert to the more correct array size, and correct a KASSERT to
only allow proper values. ENTROPYSOURCE is a maxval+1, not an
allowable number.

Suggested loose protons in the solution: phk
Prefers to keep the pH close to seven: markm

Fix off-by-one (too little!) array size problem.

Detected by: Coverity (ID#661)

stop including rijndael-api-fst.h from rijndael.h.
this is required to integrate opencrypto into crypto.

netchild's mega-patch to isolate compiler dependencies into a central
place.

This moves the dependency on GCC's and other compiler's features into
the central sys/cdefs.h file, while the individual source files can
then refer to #ifdef __COMPILER_FEATURE_FOO where they by now used to
refer to #if __GNUC__ > 3.1415 && __BARC__ <= 42.

By now, GCC and ICC (the Intel compiler) have been actively tested on
IA32 platforms by netchild. Extension to other compilers is supposed
to be possible, of course.

Submitted by: netchild
Reviewed by: various developers on arch@, some time ago

Check that we have at least a 586-class CPU before calling do_cpuid().
This fixes booting on a number of 486 processors.

PR: i386/75686
Reviewed by: markm
MFC after: 1 week

Check O_NONBLOCK not IO_NDELAY.

Don't include vnode.h

Don't change the priority to PUSER when sleeping, just keep the current
priority.

(1) Move from O(n) list copies to O(1) list concatenation, which is
supported for STAILQ via STAILQ_CONCAT().

(2) Maintain a count of the number of entries in the thread-local entropy
fifo so that we can keep the other fifo counts in synch.

MFC after: 3 weeks
MFC with: randomdev_soft.c revisions 1.5 and 1.6
Suggested by: jhb (1)

Annotate that get_cyclecount() can be expensive on some platforms,
which juxtaposes nicely with the comment just above on how the
harvest function must be cheap.

Assert that the entropy source category provided by a caller submitting
entropy is valid, as an invalid source will cause dereferencing of an
array of queues to an incorrect memory location.

Modify entropy harvesting locking strategy:

- Trade off granularity to reduce overhead, since the current model
doesn't appear to reduce contention substantially: move to a single
harvest mutex protecting harvesting queues, rather than one mutex
per source plus a mutex for the free list.

- Reduce mutex operations in a harvesting event to 2 from 4, and
maintain lockless read to avoid mutex operations if the queue is
full.

- When reaping harvested entries from the queue, move all entries from
the queue at once, and when done with them, insert them all into a
thread-local queue for processing; then insert them all into the
empty fifo at once. This reduces O(4n) mutex operations to O(2)
mutex operations per wakeup.

In the future, we may want to look at re-introducing granularity,
although perhaps at the granularity of the source rather than the
source class; both the new and old strategies would cause contention
between different instances of the same source (i.e., multiple
network interfaces).

Reviewed by: markm

Perform a lockless read to test whether an entropy havesting fifo is
full, avoiding the cost of mutex operations if it is. We re-test
once the mutex is acquired to make sure it's still true before doing
the -modify-write part of the read-modify-write. Note that due to
the maximum fifo depth being pretty deep, this is unlikely to improve
harvesting performance yet.

Approved by: markm

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>

Add a Davies-Meyer style hash to the output. This is still pure
Nehemiah chip, but the work is all done in hardware.

There are three opportunities to add other entropy; the Data
Buffer, the Cipher's IV and the Cipher's key. A future commit
will exploit these opportunities.

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.

Default to harvesting everything. This is to help give a faster
startup. harvesting can be turned OFF in etc/rc.d/* if it is a
burden.

Fix "sleeping without a mutex" panic.

Fix pc98 build.

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!

kthread_exit() no longer requires Giant, so don't force callers to acquire
Giant just to call kthread_exit().

Requested by: many

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 srandom():
1) It is already called in init_main.c:proc0_post()
2) It is called each time read_random_phony() called, because "initialized"
variable is never set to 1.

Approved by: markm

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

Fix a buffer overrun in /dev/random which, due to the nature of the
kernel memory allocator, is harmless. This could be a problem for
other systems, though. I've modified Darren's patch a little.

Original patch by: Darren Schack, Isilon Systems, Inc <darrens@isilon.com>
Also analysed by: SGI, and in particular Divy Le Ray of SGI
OK'ed by: re(rwatson)

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.

No functional change. Fix comments and whitespace.

Upgrade the random device to use a "real" hash instead of building
one out of a block cipher. This has 2 advantages:
1) The code is _much_ simpler
2) We aren't committing our security to one algorithm (much as we
may think we trust AES).

While I'm here, make an explicit reseed do a slow reseed instead
of a fast; this is in line with what the original paper suggested.

Fix really dumb braino of mine; cast a sizeof() to an int, which it is
being compared to, not size_t, which it already is.

Change callers of mtx_init() to pass in an appropriate lock type name. In
most cases NULL is passed, but in some cases such as network driver locks
(which use the MTX_NETWORK_LOCK macro) and UMA zone locks, a name is used.

Tested on: i386, alpha, sparc64

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.

Staticise the random_state array.

Reviewed by: markm

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

Fix a minor buglet/typo here that gcc3 complains about.

Fix type warnings.

PR: 29101

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)

Catch up to header include changes:
- <sys/mutex.h> now requires <sys/systm.h>
- <sys/mutex.h> and <sys/sx.h> now require <sys/lock.h>

Fix nasty corruption problem where a 64bit variable was being used
(overflowed) to catch a 256bit result.

Hard work done by: jhb

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

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

Silence (harmless) warnings.

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.

Take down a comment that is no longer true.

/dev/random is ready for prime time!

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

Make a big improvement to entropy-harvesting speed by not having any
locks (only atomic assigns) in the harvest ringbuffer.

Change and clean the mutex lock interface.

mtx_enter(lock, type) becomes:

mtx_lock(lock) for sleep locks (MTX_DEF-initialized locks)
mtx_lock_spin(lock) for spin locks (MTX_SPIN-initialized)

similarily, for releasing a lock, we now have:

mtx_unlock(lock) for MTX_DEF and mtx_unlock_spin(lock) for MTX_SPIN.
We change the caller interface for the two different types of locks
because the semantics are entirely different for each case, and this
makes it explicitly clear and, at the same time, it rids us of the
extra `type' argument.

The enter->lock and exit->unlock change has been made with the idea
that we're "locking data" and not "entering locked code" in mind.

Further, remove all additional "flags" previously passed to the
lock acquire/release routines with the exception of two:

MTX_QUIET and MTX_NOSWITCH

The functionality of these flags is preserved and they can be passed
to the lock/unlock routines by calling the corresponding wrappers:

mtx_{lock, unlock}_flags(lock, flag(s)) and
mtx_{lock, unlock}_spin_flags(lock, flag(s)) for MTX_DEF and MTX_SPIN
locks, respectively.

Re-inline some lock acq/rel code; in the sleep lock case, we only
inline the _obtain_lock()s in order to ensure that the inlined code
fits into a cache line. In the spin lock case, we inline recursion and
actually only perform a function call if we need to spin. This change
has been made with the idea that we generally tend to avoid spin locks
and that also the spin locks that we do have and are heavily used
(i.e. sched_lock) do recurse, and therefore in an effort to reduce
function call overhead for some architectures (such as alpha), we
inline recursion for this case.

Create a new malloc type for the witness code and retire from using
the M_DEV type. The new type is called M_WITNESS and is only declared
if WITNESS is enabled.

Begin cleaning up some machdep/mutex.h code - specifically updated the
"optimized" inlined code in alpha/mutex.h and wrote MTX_LOCK_SPIN
and MTX_UNLOCK_SPIN asm macros for the i386/mutex.h as we presently
need those.

Finally, caught up to the interface changes in all sys code.

Contributors: jake, jhb, jasone (in no particular order)

Fix typos: initalise -> initialise.

Initalise is not an english word.

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>.

Major speedup to /dev/random and the kernel thread that reseeds it.

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.

Fix safety-net code. While technically a bug, I'm delighted to see
that it has never (apparently) been invoked.

Submitted by: ache

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

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

More comment changing. Keep documentation in one place.

Correct a comment. This represents a very minor policy change of my
intentions with this code.

Stop explicitly using nanotime(9) and use the new get_cyclecounter(9)
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).

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>.

Remove unneeded #include <sys/proc.h> lines.

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.

Catch up to moving headers:
- machine/ipl.h -> sys/ipl.h
- machine/mutex.h -> sys/mutex.h

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

Remove the mtx_t, witness_t, and witness_blessed_t types. Instead, just
use struct mtx, struct witness, and struct witness_blessed.

Requested by: bde

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

Move the prototypes for random_set_wakeup* from yarrow.c to yarrow.h so that
both yarrow.c and harvest.c can use them.

Approved by: markm

- Use RFHIGHPID when creating the kthread to get a more sensible pid.
- Don't fake walking a tailq. Instead, use a while loop that pulls items
off the head of the queue while the queue is not empty.

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.

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")

Clean this up with some BDE-inspired fixes.

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.

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.

Storing to a pointer is (effectively) atomic; no need to protect this
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

I think I need to move the newly static variables to the random_state
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).

One should never allocate 4-kilobyte structs and such on the interrupt
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

Provide more splsofttq() protection for the reseed task (running out of
taskqueue_swi).

Make sure that tasks (running out of taskqueue_swi at splsofttq)
are not interfered with by the harvester.

Yarrow tweaks; separate the fast and slow reseed tasks so that they don't
stomp on each other; provide constant names (as enums) for the harvester
to use (makes it more self-documenting).

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 non-module case.

Thanks-to: SOS

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