tree 2c8693d5d03312ed106d4688f7b6bf41d956803e
parent daeafc22c66ad48f6b32fc8d3362eb9ba31b774e
author David Benjamin <davidben@chromium.org> 1435686779 -0400
committer Adam Langley <agl@google.com> 1435700502 +0000

Add RAND_set_urandom_fd.

Chromium uses a zygote process and a sandbox on Linux. In order for RAND_bytes
to be functional and guaranteed fork-safe inside the renderers, /dev/urandom
must be prewarmed. Calling RAND_bytes initializes a thread-local ChaCha20 key
when rdrand is available. So that key is fork-safe and to avoid tempting any
dragons by touching pthreads APIs before a non-exec fork, add a
RAND_set_urandom_fd API. It allows the consumer to supply the /dev/urandom fd
and promises to be fork-safe, both in initializing key material and use of
pthreads.

This doesn't affect any current shipping versions of Chrome.

BUG=462040

Change-Id: I1037e21e525918971380e4ea1371703c8237a0b0
Reviewed-on: https://boringssl-review.googlesource.com/5302
Reviewed-by: Adam Langley <agl@google.com>