cvs commit: src/sys/kern kern_random.c

[Matthew Dillon]

dillon      2006/04/12 11:28:30 PDT

DragonFly src repository

  Modified files:
    sys/kern             kern_random.c 
  Log:
  Note: the previous rev's CVS comment was messed up due to an editor snafu.
  
  /dev/random was almost always returning 0 bytes.  This was due to several
  factors, primarily the fact that the stack smash handler reads 32 bytes from
  /dev/urandom every time a program is exec'd, and because /dev/random and
  /dev/urandom share the same pool.
  
  * Give /dev/random and /dev/urandom their own separate pools.
  
  * Be slightly less conservative on the number of bits of randomness we
    think we've added.
  
  * extract_entropy() calls add_timer_randomness(), which adds entropy.  This
    can create a situation where entropy always appears to be available when,
    in fact, it is of very low quality.  Add a little hysteresis so degenerate
    cases return 0 bytes instead of 1 byte.
  
  * Also (in this commit) fix a bug in the previous commit where the randomness
    added was accidently halved.
  
  Reported-by: David Rhodus
  
  Revision  Changes    Path
  1.14      +11 -13    src/sys/kern/kern_random.c


http://www.dragonflybsd.org/cvsweb/src/sys/kern/kern_random.c.diff?r1=1.13&r2=1.14&f=u