[PATCH] crypto/gcrypt: prefer kernel as direct source of entropy

["Cristian Rodríguez" <cristian@rodriguez.im>]

gcrypt by default uses an userspace RNG, which cannot know
when it is time to discard/invalidate its buffer
(suspend, resume, vm forks, other corner cases)
as a "when to discard" event is unavailable to userspace.

Set GCRYCTL_SET_PREFERRED_RNG_TYPE to GCRY_RNG_TYPE_SYSTEM
which must be done before the first call to gcry_check_version()

Signed-off-by: Cristian Rodríguez <cristian@rodriguez.im>
---
 crypto/init.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/crypto/init.c b/crypto/init.c
index fb7f1bff10..0c3fe6a841 100644
--- a/crypto/init.c
+++ b/crypto/init.c
@@ -60,6 +60,7 @@ int qcrypto_init(Error **errp)
 #endif
 
 #ifdef CONFIG_GCRYPT
+    gcry_control(GCRYCTL_SET_PREFERRED_RNG_TYPE, GCRY_RNG_TYPE_SYSTEM);
     if (!gcry_check_version(NULL)) {
         error_setg(errp, "Unable to initialize gcrypt");
         return -1;
-- 
2.43.0