From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Sat, 16 Nov 2013 18:19:15 +0000 (-0800)
Subject: Merge tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso... 
X-Git-Tag: v6.6-pxa1908~24326
X-Git-Url: https://git.dujemihanovic.xyz/?a=commitdiff_plain;h=0891ad829d2a0501053703df66029e843e3b8365;p=linux.git

Merge tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random

Pull /dev/random changes from Ted Ts'o:
 "The /dev/random changes for 3.13 including a number of improvements in
  the following areas: performance, avoiding waste of entropy, better
  tracking of entropy estimates, support for non-x86 platforms that have
  a register which can't be used for fine-grained timekeeping, but which
  might be good enough for the random driver.

  Also add some printk's so that we can see how quickly /dev/urandom can
  get initialized, and when programs try to use /dev/urandom before it
  is fully initialized (since this could be a security issue).  This
  shouldn't be an issue on x86 desktop/laptops --- a test on my Lenovo
  T430s laptop shows that /dev/urandom is getting fully initialized
  approximately two seconds before the root file system is mounted
  read/write --- this may be an issue with ARM and MIPS embedded/mobile
  systems, though.  These printk's will be a useful canary before
  potentially adding a future change to start blocking processes which
  try to read from /dev/urandom before it is initialized, which is
  something FreeBSD does already for security reasons, and which
  security folks have been agitating for Linux to also adopt"

* tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random:
  random: add debugging code to detect early use of get_random_bytes()
  random: initialize the last_time field in struct timer_rand_state
  random: don't zap entropy count in rand_initialize()
  random: printk notifications for urandom pool initialization
  random: make add_timer_randomness() fill the nonblocking pool first
  random: convert DEBUG_ENT to tracepoints
  random: push extra entropy to the output pools
  random: drop trickle mode
  random: adjust the generator polynomials in the mixing function slightly
  random: speed up the fast_mix function by a factor of four
  random: cap the rate which the /dev/urandom pool gets reseeded
  random: optimize the entropy_store structure
  random: optimize spinlock use in add_device_randomness()
  random: fix the tracepoint for get_random_bytes(_arch)
  random: account for entropy loss due to overwrites
  random: allow fractional bits to be tracked
  random: statically compute poolbitshift, poolbytes, poolbits
  random: mix in architectural randomness earlier in extract_buf()
---

0891ad829d2a0501053703df66029e843e3b8365
diff --cc drivers/char/random.c
index 4fe5609eeb72,cdf4cfb2da4d..429b75bb60e8
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@@ -255,7 -255,11 +255,8 @@@
  #include <linux/fips.h>
  #include <linux/ptrace.h>
  #include <linux/kmemcheck.h>
+ #include <linux/workqueue.h>
 -
 -#ifdef CONFIG_GENERIC_HARDIRQS
 -# include <linux/irq.h>
 -#endif
 +#include <linux/irq.h>
  
  #include <asm/processor.h>
  #include <asm/uaccess.h>
@@@ -601,12 -654,14 +651,13 @@@ retry
  	if (cmpxchg(&r->entropy_count, orig, entropy_count) != orig)
  		goto retry;
  
- 	if (!r->initialized && nbits > 0) {
- 		r->entropy_total += nbits;
- 		if (r->entropy_total > 128) {
- 			r->initialized = 1;
- 			if (r == &nonblocking_pool)
- 				prandom_reseed_late();
+ 	r->entropy_total += nbits;
 -	if (!r->initialized && nbits > 0) {
 -		if (r->entropy_total > 128) {
 -			if (r == &nonblocking_pool)
 -				pr_notice("random: %s pool is initialized\n",
 -					  r->name);
 -			r->initialized = 1;
 -			r->entropy_total = 0;
++	if (!r->initialized && 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);
  		}
  	}