---
- branch: MAIN
  date: Sun Jul 21 22:30:19 UTC 2013
  files:
  - new: '1.16'
    old: '1.15'
    path: src/sys/dev/rndpseudo.c
    pathrev: src/sys/dev/rndpseudo.c@1.16
    type: modified
  id: 20130721T223019Z.9ccf810b97f878348d0a289f8cb3a0f5eebbd704
  log: |
    When reading from /dev/random, block at most once in cprng_strong.

    We are not obligated to return exactly as many bytes as requested,
    and many applications -- notably those that use stdio or otherwise
    buffered I/O to read from /dev/random -- try to read many more than
    32 bytes at a time from /dev/random even if all they are about to use
    is 32 bytes.

    In this case, blocking until we have enough entropy to fill a large
    buffer causes needless application delays, e.g. causing cgdconfig
    (which reads from /dev/random with stdio) to hang at boot when trying
    to configure a random-keyed device for swap.

    Patch tested by Aran Clauson.  Fixes PR kern/48028.
  module: src
  subject: 'CVS commit: src/sys/dev'
  unixtime: '1374445819'
  user: riastradh