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CVS log for src/sys/sys/cprng.h

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Default branch: MAIN
Current tag: MAIN


Revision 1.6 / (download) - annotate - [select for diffs], Sun Nov 25 15:29:45 2012 UTC (5 months, 3 weeks ago) by christos
Branch: MAIN
CVS Tags: yamt-pagecache-base8, yamt-pagecache-base7, tls-maxphys-nbase, tls-maxphys-base, khorben-n900, agc-symver-base, agc-symver, HEAD
Changes since 1.5: +5 -1 lines
Diff to previous 1.5 (colored)

add an snprintb format.

Revision 1.5 / (download) - annotate - [select for diffs], Tue Apr 17 02:50:39 2012 UTC (13 months ago) by tls
Branch: MAIN
CVS Tags: yamt-pagecache-base6, yamt-pagecache-base5, jmcneill-usbmp-base9, jmcneill-usbmp-base10
Branch point for: tls-maxphys
Changes since 1.4: +2 -2 lines
Diff to previous 1.4 (colored)

Address multiple problems with rnd(4)/cprng(9):

1) Add a per-cpu CPRNG to handle short reads from /dev/urandom so that
   programs like perl don't drain the entropy pool dry by repeatedly
   opening, reading 4 bytes, closing.

2) Really fix the locking around reseeds and destroys.

3) Fix the opportunistic-reseed strategy so it actually works, reseeding
   existing RNGs once each (as they are used, so idle RNGs don't get
   reseeded) until the pool is half empty or newly full again.

Revision 1.4 / (download) - annotate - [select for diffs], Sat Dec 17 20:05:40 2011 UTC (17 months ago) by tls
Branch: MAIN
CVS Tags: yamt-pagecache-base4, netbsd-6-base, jmcneill-usbmp-base8, jmcneill-usbmp-base7, jmcneill-usbmp-base6, jmcneill-usbmp-base5, jmcneill-usbmp-base4, jmcneill-usbmp-base3, jmcneill-usbmp-base2
Branch point for: yamt-pagecache, netbsd-6
Changes since 1.3: +42 -11 lines
Diff to previous 1.3 (colored)


Separate /dev/random pseudodevice implemenation from kernel entropy pool
implementation.  Rewrite pseudodevice code to use cprng_strong(9).

The new pseudodevice is cloning, so each caller gets bits from a stream
generated with its own key.  Users of /dev/urandom get their generators
keyed on a "best effort" basis -- the kernel will rekey generators
whenever the entropy pool hits the high water mark -- while users of
/dev/random get their generators rekeyed every time key-length bits
are output.

The underlying cprng_strong API can use AES-256 or AES-128, but we use
AES-128 because of concerns about related-key attacks on AES-256.  This
improves performance (and reduces entropy pool depletion) significantly
for users of /dev/urandom but does cause users of /dev/random to rekey
twice as often.

Also fixes various bugs (including some missing locking and a reseed-counter
overflow in the CTR_DRBG code) found while testing this.

For long reads, this generator is approximately 20 times as fast as the
old generator (dd with bs=64K yields 53MB/sec on 2Ghz Core2 instead of
2.5MB/sec) and also uses a separate mutex per instance so concurrency
is greatly improved.  For reads of typical key sizes for modern
cryptosystems (16-32 bytes) performance is about the same as the old
code: a little better for 32 bytes, a little worse for 16 bytes.

Revision 1.3 / (download) - annotate - [select for diffs], Tue Dec 13 08:00:36 2011 UTC (17 months, 1 week ago) by mlelstv
Branch: MAIN
Changes since 1.2: +2 -2 lines
Diff to previous 1.2 (colored)

Use cprng stub functions also for _RUMP_NATIVE_ABI which is used
for archs that use native kernel modules with rump.

Revision 1.2 / (download) - annotate - [select for diffs], Mon Nov 28 08:05:07 2011 UTC (17 months, 3 weeks ago) by tls
Branch: MAIN
CVS Tags: jmcneill-usbmp-pre-base2, jmcneill-usbmp-base
Branch point for: jmcneill-usbmp
Changes since 1.1: +16 -4 lines
Diff to previous 1.1 (colored)

Remove arc4random() and arc4randbytes() from the kernel API.  Replace
arc4random() hacks in rump with stubs that call the host arc4random() to
get numbers that are hopefully actually random (arc4random() keyed with
stack junk is not).  This should fix some of the currently failing anita
tests -- we should no longer generate duplicate "random" MAC addresses in
the test environment.

Revision 1.1 / (download) - annotate - [select for diffs], Sat Nov 19 22:51:31 2011 UTC (18 months ago) by tls
Branch: MAIN

First step of random number subsystem rework described in
<20111022023242.BA26F14A158@mail.netbsd.org>.  This change includes
the following:

	An initial cleanup and minor reorganization of the entropy pool
	code in sys/dev/rnd.c and sys/dev/rndpool.c.  Several bugs are
	fixed.  Some effort is made to accumulate entropy more quickly at
	boot time.

	A generic interface, "rndsink", is added, for stream generators to
	request that they be re-keyed with good quality entropy from the pool
	as soon as it is available.

	The arc4random()/arc4randbytes() implementation in libkern is
	adjusted to use the rndsink interface for rekeying, which helps
	address the problem of low-quality keys at boot time.

	An implementation of the FIPS 140-2 statistical tests for random
	number generator quality is provided (libkern/rngtest.c).  This
	is based on Greg Rose's implementation from Qualcomm.

	A new random stream generator, nist_ctr_drbg, is provided.  It is
	based on an implementation of the NIST SP800-90 CTR_DRBG by
	Henric Jungheim.  This generator users AES in a modified counter
	mode to generate a backtracking-resistant random stream.

	An abstraction layer, "cprng", is provided for in-kernel consumers
	of randomness.  The arc4random/arc4randbytes API is deprecated for
	in-kernel use.  It is replaced by "cprng_strong".  The current
	cprng_fast implementation wraps the existing arc4random
	implementation.  The current cprng_strong implementation wraps the
	new CTR_DRBG implementation.  Both interfaces are rekeyed from
	the entropy pool automatically at intervals justifiable from best
	current cryptographic practice.

	In some quick tests, cprng_fast() is about the same speed as
	the old arc4randbytes(), and cprng_strong() is about 20% faster
	than rnd_extract_data().  Performance is expected to improve.

	The AES code in src/crypto/rijndael is no longer an optional
	kernel component, as it is required by cprng_strong, which is
	not an optional kernel component.

	The entropy pool output is subjected to the rngtest tests at
	startup time; if it fails, the system will reboot.  There is
	approximately a 3/10000 chance of a false positive from these
	tests.  Entropy pool _input_ from hardware random numbers is
	subjected to the rngtest tests at attach time, as well as the
	FIPS continuous-output test, to detect bad or stuck hardware
	RNGs; if any are detected, they are detached, but the system
	continues to run.

	A problem with rndctl(8) is fixed -- datastructures with
	pointers in arrays are no longer passed to userspace (this
	was not a security problem, but rather a major issue for
	compat32).  A new kernel will require a new rndctl.

	The sysctl kern.arandom() and kern.urandom() nodes are hooked
	up to the new generators, but the /dev/*random pseudodevices
	are not, yet.

	Manual pages for the new kernel interfaces are forthcoming.

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