From 6f3e9754ef9446cb8a9f98e593aed23a730c4c10 Mon Sep 17 00:00:00 2001 From: Laurent Bercot Date: Thu, 15 Sep 2016 11:48:18 +0000 Subject: Add s6-fillurandompool --- doc/index.html | 1 + doc/s6-fillurandompool.html | 74 +++++++++++++++++++++++++++++++++++++++++++++ doc/s6-freeramdisk.html | 2 +- doc/upgrade.html | 2 ++ 4 files changed, 78 insertions(+), 1 deletion(-) create mode 100644 doc/s6-fillurandompool.html (limited to 'doc') diff --git a/doc/index.html b/doc/index.html index b3ade25..292d81a 100644 --- a/doc/index.html +++ b/doc/index.html @@ -88,6 +88,7 @@ the previous versions of s6-linux-utils and the current one.
  • The s6-devd program
  • The s6-uevent-listener program
  • The s6-uevent-spawner program
    • +
  • The s6-fillurandompool program
  • The s6-freeramdisk program
  • The s6-hostname program
  • The s6-logwatch program
    • diff --git a/doc/s6-fillurandompool.html b/doc/s6-fillurandompool.html new file mode 100644 index 0000000..777307e --- /dev/null +++ b/doc/s6-fillurandompool.html @@ -0,0 +1,74 @@ + + + + + + s6-linux-utils: the s6-fillurandompool program + + + + + + +

    +s6-linux-utils
    +Software
    +skarnet.org +

    + +

    The s6-fillurandompool program

    + +

    +s6-fillurandompool blocks until the machine's +/dev/urandom entropy pool is filled up. Then it exits. +

    + +

    Interface

    + +
    +     s6-fillurandompool
+
    + +

    Rationale

    + +

    + For some reason, Linux has two separate entropy pools: one for +/dev/random and one for /dev/urandom. +

    + +

    + Reading from /dev/random blocks when its entropy pool is +not full enough, so it will never return weak random data. (Reading +from /dev/random is overkill anyway, and +you +should not be doing it.) +

    + +

    + However, reading from /dev/urandom (which +you should be doing) +will not block, even though the entropy pool may not have been +initialized yet. That's the only insecure thing about it: at boot time, +/dev/urandom may return weak random data, until its entropy +pool has filled up. +

    + +

    + s6-fillurandompool is meant to address this issue. Call it once +early on in your boot scripts, before you need any serious random data; +when it exits, the /dev/urandom pool has been properly initialized, +and it is now safe to read from /dev/urandom every time you need +random data, until the machine shuts down. +

    + +

    Notes

    + + + + + diff --git a/doc/s6-freeramdisk.html b/doc/s6-freeramdisk.html index a2baa68..880c4d0 100644 --- a/doc/s6-freeramdisk.html +++ b/doc/s6-freeramdisk.html @@ -19,7 +19,7 @@

    The s6-freeramdisk program

    -freeramdisk frees the memory occupied by a RAM disk. Call it +s6-freeramdisk frees the memory occupied by a RAM disk. Call it when your RAM disk is not in use anymore.

    diff --git a/doc/upgrade.html b/doc/upgrade.html index 1851be9..6c843ce 100644 --- a/doc/upgrade.html +++ b/doc/upgrade.html @@ -26,6 +26,8 @@ by this package anymore: they're now a part of the s6-linux-init package. +
  • The s6-fillurandompool +program has been added.

    • in 2.1.0.0

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