Re: [chrony-users] Chrony vs. Linux RNG

[Miroslav Lichvar <mlichvar@xxxxxxxxxx>]

On Mon, Apr 23, 2018 at 12:05:55PM +0200, Holger Hoffstätte wrote:
> So it's probably indeed blocking in too-early getrandom() (thanks for
> pointing that out!)and falling back to urandom with GRND_NONBLOCK could
> work. Let me know if I can try any patches.

You can try the following patch. It should prevent getrandom() from
blocking and allow fall back to /dev/urandom.

--- a/util.c
+++ b/util.c
@@ -1224,7 +1224,7 @@ get_random_bytes_getrandom(char *buf, unsigned int len)
       if (disabled)
         break;
 
-      if (getrandom(rand_buf, sizeof (rand_buf), 0) != sizeof (rand_buf)) {
+      if (getrandom(rand_buf, sizeof (rand_buf), GRND_NONBLOCK) != sizeof (rand_buf)) {
         disabled = 1;
         break;
       }

-- 
Miroslav Lichvar

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