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Merge branch 'prandom'

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prandom fixes/improvements

====================
It would be great if you could still consider this series that fixes and
improves prandom for 3.13. We have sent it to netdev as prandom() originally
came from net/core/utils.c and networking is its main user. For a detailled
description, please see individual patches.

For patch 3 in this series, there will be a minor merge conflict with the
random tree that is for 3.13. See below how to resolve it.

====
Hannes says: on merge with the random tree I would suggest to resolve the
conflict in drivers/char/random.c like this:

if (r->entropy_total > 128) {
	r->initialized = 1;
	r->entropy_total = 0;
	if (r == &nonblocking_pool) {
		prandom_reseed_late();
		pr_notice("random: %s pool is initialized\n",
			  r->name);
	}
}

So it won't generate a warning if DEBUG_RANDOM_BOOT gets activated.
====

Patch 1 should probably also go to -stable.

Set tested on 32 and 64 bit machines.

Thanks a lot!

Ref. original discussion: http://patchwork.ozlabs.org/patch/289951/
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2013-11-11 14:33:06 -05:00
commit 75ecab1df1
5 changed files with 294 additions and 46 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
drivers/char/random.c
View File

@ -603,8 +603,11 @@ retry:
if (!r->initialized && nbits > 0) {
r->entropy_total += nbits;
if (r->entropy_total > 128)
if (r->entropy_total > 128) {
r->initialized = 1;
if (r == &nonblocking_pool)
prandom_reseed_late();
}
}
trace_credit_entropy_bits(r->name, nbits, entropy_count,

14
include/linux/random.h
View File

@ -29,8 +29,13 @@ unsigned long randomize_range(unsigned long start, unsigned long end, unsigned l
u32 prandom_u32(void);
void prandom_bytes(void *buf, int nbytes);
void prandom_seed(u32 seed);
void prandom_reseed_late(void);
u32 prandom_u32_state(struct rnd_state *);
struct rnd_state {
__u32 s1, s2, s3, s4;
};
u32 prandom_u32_state(struct rnd_state *state);
void prandom_bytes_state(struct rnd_state *state, void *buf, int nbytes);
/*
@ -50,9 +55,10 @@ static inline void prandom_seed_state(struct rnd_state *state, u64 seed)
{
u32 i = (seed >> 32) ^ (seed << 10) ^ seed;
state->s1 = __seed(i, 1);
state->s2 = __seed(i, 7);
state->s3 = __seed(i, 15);
state->s1 = __seed(i, 2U);
state->s2 = __seed(i, 8U);
state->s3 = __seed(i, 16U);
state->s4 = __seed(i, 128U);
}
#ifdef CONFIG_ARCH_RANDOM

7
include/uapi/linux/random.h
View File

@ -40,11 +40,4 @@ struct rand_pool_info {
__u32 buf[0];
};
struct rnd_state {
__u32 s1, s2, s3;
};
/* Exported functions */
#endif /* _UAPI_LINUX_RANDOM_H */

7
lib/Kconfig
View File

@ -189,6 +189,13 @@ config AUDIT_GENERIC
depends on AUDIT && !AUDIT_ARCH
default y
config RANDOM32_SELFTEST
bool "PRNG perform self test on init"
default n
help
This option enables the 32 bit PRNG library functions to perform a
self test on initialization.
#
# compression support is select'ed if needed
#

307
lib/random32.c
View File

@ -2,19 +2,19 @@
This is a maximally equidistributed combined Tausworthe generator
based on code from GNU Scientific Library 1.5 (30 Jun 2004)
x_n = (s1_n ^ s2_n ^ s3_n)
lfsr113 version:
s1_{n+1} = (((s1_n & 4294967294) <<12) ^ (((s1_n <<13) ^ s1_n) >>19))
s2_{n+1} = (((s2_n & 4294967288) << 4) ^ (((s2_n << 2) ^ s2_n) >>25))
s3_{n+1} = (((s3_n & 4294967280) <<17) ^ (((s3_n << 3) ^ s3_n) >>11))
x_n = (s1_n ^ s2_n ^ s3_n ^ s4_n)
The period of this generator is about 2^88.
s1_{n+1} = (((s1_n & 4294967294) << 18) ^ (((s1_n << 6) ^ s1_n) >> 13))
s2_{n+1} = (((s2_n & 4294967288) << 2) ^ (((s2_n << 2) ^ s2_n) >> 27))
s3_{n+1} = (((s3_n & 4294967280) << 7) ^ (((s3_n << 13) ^ s3_n) >> 21))
s4_{n+1} = (((s4_n & 4294967168) << 13) ^ (((s4_n << 3) ^ s4_n) >> 12))
The period of this generator is about 2^113 (see erratum paper).
From: P. L'Ecuyer, "Maximally Equidistributed Combined Tausworthe
Generators", Mathematics of Computation, 65, 213 (1996), 203--213.
This is available on the net from L'Ecuyer's home page,
Generators", Mathematics of Computation, 65, 213 (1996), 203--213:
http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme.ps
ftp://ftp.iro.umontreal.ca/pub/simulation/lecuyer/papers/tausme.ps
@ -29,7 +29,7 @@
that paper.)
This affects the seeding procedure by imposing the requirement
s1 > 1, s2 > 7, s3 > 15.
s1 > 1, s2 > 7, s3 > 15, s4 > 127.
*/
@ -38,6 +38,11 @@
#include <linux/export.h>
#include <linux/jiffies.h>
#include <linux/random.h>
#include <linux/sched.h>
#ifdef CONFIG_RANDOM32_SELFTEST
static void __init prandom_state_selftest(void);
#endif
static DEFINE_PER_CPU(struct rnd_state, net_rand_state);
@ -52,11 +57,12 @@ u32 prandom_u32_state(struct rnd_state *state)
{
#define TAUSWORTHE(s,a,b,c,d) ((s&c)<<d) ^ (((s <<a) ^ s)>>b)
state->s1 = TAUSWORTHE(state->s1, 13, 19, 4294967294UL, 12);
state->s2 = TAUSWORTHE(state->s2, 2, 25, 4294967288UL, 4);
state->s3 = TAUSWORTHE(state->s3, 3, 11, 4294967280UL, 17);
state->s1 = TAUSWORTHE(state->s1, 6U, 13U, 4294967294U, 18U);
state->s2 = TAUSWORTHE(state->s2, 2U, 27U, 4294967288U, 2U);
state->s3 = TAUSWORTHE(state->s3, 13U, 21U, 4294967280U, 7U);
state->s4 = TAUSWORTHE(state->s4, 3U, 12U, 4294967168U, 13U);
return (state->s1 ^ state->s2 ^ state->s3);
return (state->s1 ^ state->s2 ^ state->s3 ^ state->s4);
}
EXPORT_SYMBOL(prandom_u32_state);
@ -126,6 +132,38 @@ void prandom_bytes(void *buf, int bytes)
}
EXPORT_SYMBOL(prandom_bytes);
static void prandom_warmup(struct rnd_state *state)
{
/* Calling RNG ten times to satify recurrence condition */
prandom_u32_state(state);
prandom_u32_state(state);
prandom_u32_state(state);
prandom_u32_state(state);
prandom_u32_state(state);
prandom_u32_state(state);
prandom_u32_state(state);
prandom_u32_state(state);
prandom_u32_state(state);
prandom_u32_state(state);
}
static void prandom_seed_very_weak(struct rnd_state *state, u32 seed)
{
/* Note: This sort of seeding is ONLY used in test cases and
* during boot at the time from core_initcall until late_initcall
* as we don't have a stronger entropy source available yet.
* After late_initcall, we reseed entire state, we have to (!),
* otherwise an attacker just needs to search 32 bit space to
* probe for our internal 128 bit state if he knows a couple
* of prandom32 outputs!
*/
#define LCG(x) ((x) * 69069U) /* super-duper LCG */
state->s1 = __seed(LCG(seed), 2U);
state->s2 = __seed(LCG(state->s1), 8U);
state->s3 = __seed(LCG(state->s2), 16U);
state->s4 = __seed(LCG(state->s3), 128U);
}
/**
* prandom_seed - add entropy to pseudo random number generator
* @seed: seed value
@ -141,7 +179,9 @@ void prandom_seed(u32 entropy)
*/
for_each_possible_cpu (i) {
struct rnd_state *state = &per_cpu(net_rand_state, i);
state->s1 = __seed(state->s1 ^ entropy, 1);
state->s1 = __seed(state->s1 ^ entropy, 2U);
prandom_warmup(state);
}
}
EXPORT_SYMBOL(prandom_seed);
@ -154,46 +194,245 @@ static int __init prandom_init(void)
{
int i;
#ifdef CONFIG_RANDOM32_SELFTEST
prandom_state_selftest();
#endif
for_each_possible_cpu(i) {
struct rnd_state *state = &per_cpu(net_rand_state,i);
#define LCG(x) ((x) * 69069) /* super-duper LCG */
state->s1 = __seed(LCG(i + jiffies), 1);
state->s2 = __seed(LCG(state->s1), 7);
state->s3 = __seed(LCG(state->s2), 15);
/* "warm it up" */
prandom_u32_state(state);
prandom_u32_state(state);
prandom_u32_state(state);
prandom_u32_state(state);
prandom_u32_state(state);
prandom_u32_state(state);
prandom_seed_very_weak(state, (i + jiffies) ^ random_get_entropy());
prandom_warmup(state);
}
return 0;
}
core_initcall(prandom_init);
static void __prandom_timer(unsigned long dontcare);
static DEFINE_TIMER(seed_timer, __prandom_timer, 0, 0);
static void __prandom_timer(unsigned long dontcare)
{
u32 entropy;
get_random_bytes(&entropy, sizeof(entropy));
prandom_seed(entropy);
/* reseed every ~60 seconds, in [40 .. 80) interval with slack */
seed_timer.expires = jiffies + (40 * HZ + (prandom_u32() % (40 * HZ)));
add_timer(&seed_timer);
}
static void prandom_start_seed_timer(void)
{
set_timer_slack(&seed_timer, HZ);
seed_timer.expires = jiffies + 40 * HZ;
add_timer(&seed_timer);
}
/*
* Generate better values after random number generator
* is fully initialized.
*/
static int __init prandom_reseed(void)
static void __prandom_reseed(bool late)
{
int i;
unsigned long flags;
static bool latch = false;
static DEFINE_SPINLOCK(lock);
/* only allow initial seeding (late == false) once */
spin_lock_irqsave(&lock, flags);
if (latch && !late)
goto out;
latch = true;
for_each_possible_cpu(i) {
struct rnd_state *state = &per_cpu(net_rand_state,i);
u32 seeds[3];
u32 seeds[4];
get_random_bytes(&seeds, sizeof(seeds));
state->s1 = __seed(seeds[0], 1);
state->s2 = __seed(seeds[1], 7);
state->s3 = __seed(seeds[2], 15);
state->s1 = __seed(seeds[0], 2U);
state->s2 = __seed(seeds[1], 8U);
state->s3 = __seed(seeds[2], 16U);
state->s4 = __seed(seeds[3], 128U);
/* mix it in */
prandom_u32_state(state);
prandom_warmup(state);
}
out:
spin_unlock_irqrestore(&lock, flags);
}
void prandom_reseed_late(void)
{
__prandom_reseed(true);
}
static int __init prandom_reseed(void)
{
__prandom_reseed(false);
prandom_start_seed_timer();
return 0;
}
late_initcall(prandom_reseed);
#ifdef CONFIG_RANDOM32_SELFTEST
static struct prandom_test1 {
u32 seed;
u32 result;
} test1[] = {
{ 1U, 3484351685U },
{ 2U, 2623130059U },
{ 3U, 3125133893U },
{ 4U, 984847254U },
};
static struct prandom_test2 {
u32 seed;
u32 iteration;
u32 result;
} test2[] = {
/* Test cases against taus113 from GSL library. */
{ 931557656U, 959U, 2975593782U },
{ 1339693295U, 876U, 3887776532U },
{ 1545556285U, 961U, 1615538833U },
{ 601730776U, 723U, 1776162651U },
{ 1027516047U, 687U, 511983079U },
{ 416526298U, 700U, 916156552U },
{ 1395522032U, 652U, 2222063676U },
{ 366221443U, 617U, 2992857763U },
{ 1539836965U, 714U, 3783265725U },
{ 556206671U, 994U, 799626459U },
{ 684907218U, 799U, 367789491U },
{ 2121230701U, 931U, 2115467001U },
{ 1668516451U, 644U, 3620590685U },
{ 768046066U, 883U, 2034077390U },
{ 1989159136U, 833U, 1195767305U },
{ 536585145U, 996U, 3577259204U },
{ 1008129373U, 642U, 1478080776U },
{ 1740775604U, 939U, 1264980372U },
{ 1967883163U, 508U, 10734624U },
{ 1923019697U, 730U, 3821419629U },
{ 442079932U, 560U, 3440032343U },
{ 1961302714U, 845U, 841962572U },
{ 2030205964U, 962U, 1325144227U },
{ 1160407529U, 507U, 240940858U },
{ 635482502U, 779U, 4200489746U },
{ 1252788931U, 699U, 867195434U },
{ 1961817131U, 719U, 668237657U },
{ 1071468216U, 983U, 917876630U },
{ 1281848367U, 932U, 1003100039U },
{ 582537119U, 780U, 1127273778U },
{ 1973672777U, 853U, 1071368872U },
{ 1896756996U, 762U, 1127851055U },
{ 847917054U, 500U, 1717499075U },
{ 1240520510U, 951U, 2849576657U },
{ 1685071682U, 567U, 1961810396U },
{ 1516232129U, 557U, 3173877U },
{ 1208118903U, 612U, 1613145022U },
{ 1817269927U, 693U, 4279122573U },
{ 1510091701U, 717U, 638191229U },
{ 365916850U, 807U, 600424314U },
{ 399324359U, 702U, 1803598116U },
{ 1318480274U, 779U, 2074237022U },
{ 697758115U, 840U, 1483639402U },
{ 1696507773U, 840U, 577415447U },
{ 2081979121U, 981U, 3041486449U },
{ 955646687U, 742U, 3846494357U },
{ 1250683506U, 749U, 836419859U },
{ 595003102U, 534U, 366794109U },
{ 47485338U, 558U, 3521120834U },
{ 619433479U, 610U, 3991783875U },
{ 704096520U, 518U, 4139493852U },
{ 1712224984U, 606U, 2393312003U },
{ 1318233152U, 922U, 3880361134U },
{ 855572992U, 761U, 1472974787U },
{ 64721421U, 703U, 683860550U },
{ 678931758U, 840U, 380616043U },
{ 692711973U, 778U, 1382361947U },
{ 677703619U, 530U, 2826914161U },
{ 92393223U, 586U, 1522128471U },
{ 1222592920U, 743U, 3466726667U },
{ 358288986U, 695U, 1091956998U },
{ 1935056945U, 958U, 514864477U },
{ 735675993U, 990U, 1294239989U },
{ 1560089402U, 897U, 2238551287U },
{ 70616361U, 829U, 22483098U },
{ 368234700U, 731U, 2913875084U },
{ 20221190U, 879U, 1564152970U },
{ 539444654U, 682U, 1835141259U },
{ 1314987297U, 840U, 1801114136U },
{ 2019295544U, 645U, 3286438930U },
{ 469023838U, 716U, 1637918202U },
{ 1843754496U, 653U, 2562092152U },
{ 400672036U, 809U, 4264212785U },
{ 404722249U, 965U, 2704116999U },
{ 600702209U, 758U, 584979986U },
{ 519953954U, 667U, 2574436237U },
{ 1658071126U, 694U, 2214569490U },
{ 420480037U, 749U, 3430010866U },
{ 690103647U, 969U, 3700758083U },
{ 1029424799U, 937U, 3787746841U },
{ 2012608669U, 506U, 3362628973U },
{ 1535432887U, 998U, 42610943U },
{ 1330635533U, 857U, 3040806504U },
{ 1223800550U, 539U, 3954229517U },
{ 1322411537U, 680U, 3223250324U },
{ 1877847898U, 945U, 2915147143U },
{ 1646356099U, 874U, 965988280U },
{ 805687536U, 744U, 4032277920U },
{ 1948093210U, 633U, 1346597684U },
{ 392609744U, 783U, 1636083295U },
{ 690241304U, 770U, 1201031298U },
{ 1360302965U, 696U, 1665394461U },
{ 1220090946U, 780U, 1316922812U },
{ 447092251U, 500U, 3438743375U },
{ 1613868791U, 592U, 828546883U },
{ 523430951U, 548U, 2552392304U },
{ 726692899U, 810U, 1656872867U },
{ 1364340021U, 836U, 3710513486U },
{ 1986257729U, 931U, 935013962U },
{ 407983964U, 921U, 728767059U },
};
static void __init prandom_state_selftest(void)
{
int i, j, errors = 0, runs = 0;
bool error = false;
for (i = 0; i < ARRAY_SIZE(test1); i++) {
struct rnd_state state;
prandom_seed_very_weak(&state, test1[i].seed);
prandom_warmup(&state);
if (test1[i].result != prandom_u32_state(&state))
error = true;
}
if (error)
pr_warn("prandom: seed boundary self test failed\n");
else
pr_info("prandom: seed boundary self test passed\n");
for (i = 0; i < ARRAY_SIZE(test2); i++) {
struct rnd_state state;
prandom_seed_very_weak(&state, test2[i].seed);
prandom_warmup(&state);
for (j = 0; j < test2[i].iteration - 1; j++)
prandom_u32_state(&state);
if (test2[i].result != prandom_u32_state(&state))
errors++;
runs++;
cond_resched();
}
if (errors)
pr_warn("prandom: %d/%d self tests failed\n", errors, runs);
else
pr_info("prandom: %d self tests passed\n", runs);
}
#endif