So the issue is the block? I make a blocking call and another app attempts to make a call during the block and will fail if it's not expecting to wait? Is that (one of) the problem(s)?
Thanks for breaking that down for me!
Thanks for breaking that down for me!
The problem is, before this patch, Linux keeps track of an entropy estimate for /dev/random, and if the estimate gets too low, read requests will block. Each read reduces the estimate significantly, so something that does a lot of reads makes it hard for other programs to do any reads in a reasonable amount of time.
If you knew the system was seeded, you could use urandom instead, but there's not a great way to know. Perhaps, you could read from random the first time, and urandom for future requests in the same process... but that only helps in long running processes; also reading once from random and using it as a seed to an in-process secure random generator works almost as well. The getrandom() syscall is really the way forward, but you would need to keep old logic conditionally or accept loss of compatibility with older releases.
In summary, it's not really fair to say GnuPG is doing it wrong, when they didn't have a way to do it right.