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[PATCH v3 0/5] /dev/random - a new approach

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  [PATCH v3 0/5] /dev/random - a new approach Stephan Mueller <smueller@chronox.de> - 2016-04-29 08:30 +0200
    [PATCH v3 4/5] crypto: LRNG - enable compile Stephan Mueller <smueller@chronox.de> - 2016-04-29 08:30 +0200
    [PATCH v3 1/5] crypto: DRBG - externalize DRBG functions for LRNG Stephan Mueller <smueller@chronox.de> - 2016-04-29 08:30 +0200

#1390790 — [PATCH v3 0/5] /dev/random - a new approach

Hi Herbert, Ted, Andi,

The following patch set provides a different approach to /dev/random which
I call Linux Random Number Generator (LRNG) to collect entropy within the Linux
kernel. The main improvements compared to the legacy /dev/random is to provide
sufficient entropy during boot time as well as in virtual environments and when
using SSDs. A secondary design goal is to limit the impact of the entropy
collection on massive parallel systems and also allow the use accelerated
cryptographic primitives. Also, all steps of the entropic data processing are
testable. Finally massive performance improvements are visible at /dev/urandom
and get_random_bytes.

The design and implementation is driven by a set of goals described in [1]
that the LRNG completely implements. Furthermore, [1] includes a
comparison with RNG design suggestions such as SP800-90B, SP800-90C, and
AIS20/31.

To Joe Perches: I have not forgotten the request to move the docuementation and
test code into patches for the kernel tree. But I would like first let the dust
settle before trying to integrate them.

To Andi Kleen: Would it be possible that you test the per-NUMA secondary DRBG
code, please? Simply apply the patches, compile the LRNG (found in the
Cryptographic API menuconfig) and then run your performance tests. Note,
I tested the correctness of the implementation on a per-CPU instantiation test
and using the fake-NUMA setup. But I do not have a real NUMA system. You may
see kernel logs when you boot with the kernel command line option of:
dyndbg="file lrng.c line 1-1900 +p"

Changes v3:
* Convert debug printk to pr_debug as suggested by Joe Perches
* Add missing \n as suggested by Joe Perches
* Do not mix in struck IRQ measurements as requested by Pavel Machek
* Add handling logic for systems without high-res timer as suggested by Pavel
  Machek -- it uses ideas from the add_interrupt_randomness of the legacy
  /dev/random implementation
* add per NUMA node secondary DRBGs as suggested by Andi Kleen -- the
  explanation of how the logic works is given in section 2.1.1 of my
  documentation [1], especially how the initial seeding is performed.

Changes v2:
* Removal of the Jitter RNG fast noise source as requested by Ted
* Addition of processing of add_input_randomness as suggested by Ted
* Update documentation and testing in [1] to cover the updates
* Addition of a SystemTap script to test add_input_randomness
* To clarify the question whether sufficient entropy is present during boot
  I added one more test in 3.3.1 [1] which demonstrates the providing of
  sufficient entropy during initialization. In the worst case of no fast noise
  sources, in the worst case of a virtual machine with only very few hardware
  devices, the testing shows that the secondary DRBG is fully seeded with 256
  bits of entropy before user space injects the random data obtained
  during shutdown of the previous boot (i.e. the requirement phrased by the
  legacy /dev/random implementation). As the writing of the random data into
  /dev/random by user space will happen before any cryptographic service
  is initialized in user space, this test demonstrates that sufficient
  entropy is already present in the LRNG at the time user space requires it
  for seeding cryptographic daemons. Note, this test result was obtained
  for different architectures, such as x86 64 bit, x86 32 bit, ARM 32 bit and
  MIPS 32 bit.

[1] http://www.chronox.de/lrng/doc/lrng.pdf

[2] http://www.chronox.de/lrng.html

Stephan Mueller (5):
  crypto: DRBG - externalize DRBG functions for LRNG
  random: conditionally compile code depending on LRNG
  crypto: Linux Random Number Generator
  crypto: LRNG - enable compile
  random: add interrupt callback to VMBus IRQ handler

 crypto/Kconfig         |   10 +
 crypto/Makefile        |    1 +
 crypto/drbg.c          |   11 +-
 crypto/lrng.c          | 1914 ++++++++++++++++++++++++++++++++++++++++++++++++
 drivers/char/random.c  |    9 +
 drivers/hv/vmbus_drv.c |    3 +
 include/crypto/drbg.h  |    7 +
 include/linux/genhd.h  |    5 +
 include/linux/random.h |    7 +-
 9 files changed, 1960 insertions(+), 7 deletions(-)
 create mode 100644 crypto/lrng.c

-- 
2.5.5

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#1390792 — [PATCH v3 4/5] crypto: LRNG - enable compile

Add LRNG compilation support.

Signed-off-by: Stephan Mueller <smueller@chronox.de>
---
 crypto/Kconfig  | 10 ++++++++++
 crypto/Makefile |  1 +
 2 files changed, 11 insertions(+)

diff --git a/crypto/Kconfig b/crypto/Kconfig
index 93a1fdc..938f2dc 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -1587,6 +1587,16 @@ config CRYPTO_JITTERENTROPY
 	  random numbers. This Jitterentropy RNG registers with
 	  the kernel crypto API and can be used by any caller.
 
+config CRYPTO_LRNG
+	bool "Linux Random Number Generator"
+	select CRYPTO_DRBG_MENU
+	help
+	  The Linux Random Number Generator (LRNG) is the replacement
+	  of the legacy /dev/random provided with drivers/char/random.c.
+	  It generates entropy from different noise sources and
+	  delivers significant entropy during boot. The LRNG only
+	  works with the presence of a high-resolution timer.
+
 config CRYPTO_USER_API
 	tristate
 
diff --git a/crypto/Makefile b/crypto/Makefile
index 4f4ef7e..7f91c8e 100644
--- a/crypto/Makefile
+++ b/crypto/Makefile
@@ -114,6 +114,7 @@ obj-$(CONFIG_CRYPTO_DRBG) += drbg.o
 obj-$(CONFIG_CRYPTO_JITTERENTROPY) += jitterentropy_rng.o
 CFLAGS_jitterentropy.o = -O0
 jitterentropy_rng-y := jitterentropy.o jitterentropy-kcapi.o
+obj-$(CONFIG_CRYPTO_LRNG) += lrng.o
 obj-$(CONFIG_CRYPTO_TEST) += tcrypt.o
 obj-$(CONFIG_CRYPTO_GHASH) += ghash-generic.o
 obj-$(CONFIG_CRYPTO_USER_API) += af_alg.o
-- 
2.5.5

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#1390796 — [PATCH v3 1/5] crypto: DRBG - externalize DRBG functions for LRNG

From 443dd61dcf2cf5a7a516c552da463ee2d8aea949 Mon Sep 17 00:00:00 2001
From: Stephan Mueller <smueller@chronox.de>
Date: Mon, 18 Apr 2016 10:04:33 +0200
Subject: 

This patch allows several DRBG functions to be called by the LRNG kernel
code paths outside the drbg.c file.

Signed-off-by: Stephan Mueller <smueller@chronox.de>
---
 crypto/drbg.c         | 11 +++++------
 include/crypto/drbg.h |  7 +++++++
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/crypto/drbg.c b/crypto/drbg.c
index 0a3538f..c339a2e 100644
--- a/crypto/drbg.c
+++ b/crypto/drbg.c
@@ -113,7 +113,7 @@
  * the SHA256 / AES 256 over other ciphers. Thus, the favored
  * DRBGs are the latest entries in this array.
  */
-static const struct drbg_core drbg_cores[] = {
+struct drbg_core drbg_cores[] = {
 #ifdef CONFIG_CRYPTO_DRBG_CTR
 	{
 		.flags = DRBG_CTR | DRBG_STRENGTH128,
@@ -205,7 +205,7 @@ static int drbg_uninstantiate(struct drbg_state *drbg);
  * Return: normalized strength in *bytes* value or 32 as default
  *	   to counter programming errors
  */
-static inline unsigned short drbg_sec_strength(drbg_flag_t flags)
+unsigned short drbg_sec_strength(drbg_flag_t flags)
 {
 	switch (flags & DRBG_STRENGTH_MASK) {
 	case DRBG_STRENGTH128:
@@ -1140,7 +1140,7 @@ static int drbg_seed(struct drbg_state *drbg, struct drbg_string *pers,
 }
 
 /* Free all substructures in a DRBG state without the DRBG state structure */
-static inline void drbg_dealloc_state(struct drbg_state *drbg)
+void drbg_dealloc_state(struct drbg_state *drbg)
 {
 	if (!drbg)
 		return;
@@ -1159,7 +1159,7 @@ static inline void drbg_dealloc_state(struct drbg_state *drbg)
  * Allocate all sub-structures for a DRBG state.
  * The DRBG state structure must already be allocated.
  */
-static inline int drbg_alloc_state(struct drbg_state *drbg)
+int drbg_alloc_state(struct drbg_state *drbg)
 {
 	int ret = -ENOMEM;
 	unsigned int sb_size = 0;
@@ -1682,8 +1682,7 @@ static int drbg_kcapi_sym(struct drbg_state *drbg, const unsigned char *key,
  *
  * return: flags
  */
-static inline void drbg_convert_tfm_core(const char *cra_driver_name,
-					 int *coreref, bool *pr)
+void drbg_convert_tfm_core(const char *cra_driver_name, int *coreref, bool *pr)
 {
 	int i = 0;
 	size_t start = 0;
diff --git a/include/crypto/drbg.h b/include/crypto/drbg.h
index d961b2b..d24ec22 100644
--- a/include/crypto/drbg.h
+++ b/include/crypto/drbg.h
@@ -268,4 +268,11 @@ enum drbg_prefixes {
 	DRBG_PREFIX3
 };
 
+extern int drbg_alloc_state(struct drbg_state *drbg);
+extern void drbg_dealloc_state(struct drbg_state *drbg);
+extern void drbg_convert_tfm_core(const char *cra_driver_name, int *coreref,
+				  bool *pr);
+extern struct drbg_core drbg_cores[];
+extern unsigned short drbg_sec_strength(drbg_flag_t flags);
+
 #endif /* _DRBG_H */
-- 
2.5.5

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