crypto: qcrypto_random_bytes() now works on windows w/o any other crypto libs

If no crypto library is included in the build, QEMU uses
qcrypto_random_bytes() to generate random data. That function tried to open
/dev/urandom or /dev/random and if opening both files failed it errored out.

Those files obviously do not exist on windows, so there the code uses
CryptGenRandom().

Furthermore there was some refactoring and a new function
qcrypto_random_init() was introduced. If a proper crypto library (gnutls or
libgcrypt) is included in the build, this function does nothing. If neither
is included it initializes the (platform specific) handles that are used by
qcrypto_random_bytes().
Either:
* a handle to /dev/urandom | /dev/random on unix like systems
* a handle to a cryptographic service provider on windows

Signed-off-by: Geert Martin Ijewski <gm.ijewski@web.de>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/crypto/init.c b/crypto/init.c
index f65207e57d..f131c42306 100644
--- a/crypto/init.c
+++ b/crypto/init.c
@@ -32,6 +32,8 @@
 #include <gcrypt.h>
 #endif
 
+#include "crypto/random.h"
+
 /* #define DEBUG_GNUTLS */
 
 /*
@@ -146,5 +148,9 @@ int qcrypto_init(Error **errp)
     gcry_control(GCRYCTL_INITIALIZATION_FINISHED, 0);
 #endif
 
+    if (qcrypto_random_init(errp) < 0) {
+        return -1;
+    }
+
     return 0;
 }