[v3,01/26] crypto: add cryptographic random byte source

diff --git a/Makefile.objs b/Makefile.objs
index fbcaa74..8f705f6 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -1,6 +1,6 @@ 
 #######################################################################
 # Common libraries for tools and emulators
-stub-obj-y = stubs/
+stub-obj-y = stubs/ crypto/
 util-obj-y = util/ qobject/ qapi/
 util-obj-y += qmp-introspect.o qapi-types.o qapi-visit.o qapi-event.o
 
diff --git a/crypto/Makefile.objs b/crypto/Makefile.objs
index a3135f1..0929c1c 100644
--- a/crypto/Makefile.objs
+++ b/crypto/Makefile.objs
@@ -8,6 +8,10 @@  crypto-obj-y += tlscredsanon.o
 crypto-obj-y += tlscredsx509.o
 crypto-obj-y += tlssession.o
 crypto-obj-y += secret.o
+crypto-obj-$(if $(CONFIG_GNUTLS),n,$(CONFIG_GCRYPT)) += random-gcrypt.o
+crypto-obj-$(CONFIG_GNUTLS) += random-gnutls.o
 
 # Let the userspace emulators avoid linking gnutls/etc
 crypto-aes-obj-y = aes.o
+
+stub-obj-y += random-stub.o
diff --git a/crypto/random-gcrypt.c b/crypto/random-gcrypt.c
new file mode 100644
index 0000000..0de9a09
--- /dev/null
+++ b/crypto/random-gcrypt.c
@@ -0,0 +1,33 @@ 
+/*
+ * QEMU Crypto random number provider
+ *
+ * Copyright (c) 2015-2016 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "qemu/osdep.h"
+
+#include "crypto/random.h"
+
+#include <gcrypt.h>
+
+int qcrypto_random_bytes(uint8_t *buf,
+                         size_t buflen,
+                         Error **errp G_GNUC_UNUSED)
+{
+    gcry_randomize(buf, buflen, GCRY_STRONG_RANDOM);
+    return 0;
+}
diff --git a/crypto/random-gnutls.c b/crypto/random-gnutls.c
new file mode 100644
index 0000000..04b45a8
--- /dev/null
+++ b/crypto/random-gnutls.c
@@ -0,0 +1,43 @@ 
+/*
+ * QEMU Crypto random number provider
+ *
+ * Copyright (c) 2015-2016 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "qemu/osdep.h"
+
+#include "crypto/random.h"
+
+#include <gnutls/gnutls.h>
+#include <gnutls/crypto.h>
+
+int qcrypto_random_bytes(uint8_t *buf,
+                         size_t buflen,
+                         Error **errp)
+{
+    int ret;
+
+    ret = gnutls_rnd(GNUTLS_RND_RANDOM, buf, buflen);
+
+    if (ret < 0) {
+        error_setg(errp, "Cannot get random bytes: %s",
+                   gnutls_strerror(ret));
+        return -1;
+    }
+
+    return 0;
+}
diff --git a/crypto/random-stub.c b/crypto/random-stub.c
new file mode 100644
index 0000000..5c2a4e1
--- /dev/null
+++ b/crypto/random-stub.c
@@ -0,0 +1,31 @@ 
+/*
+ * QEMU Crypto random number provider
+ *
+ * Copyright (c) 2015-2016 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <config-host.h>
+
+#include "crypto/random.h"
+
+int qcrypto_random_bytes(uint8_t *buf G_GNUC_UNUSED,
+                         size_t buflen G_GNUC_UNUSED,
+                         Error **errp)
+{
+    error_setg(errp, "No random byte source provided in this build");
+    return -1;
+}
diff --git a/include/crypto/random.h b/include/crypto/random.h
new file mode 100644
index 0000000..b3021c4
--- /dev/null
+++ b/include/crypto/random.h
@@ -0,0 +1,44 @@ 
+/*
+ * QEMU Crypto random number provider
+ *
+ * Copyright (c) 2015-2016 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef QCRYPTO_RANDOM_H__
+#define QCRYPTO_RANDOM_H__
+
+#include "qemu-common.h"
+#include "qapi/error.h"
+
+
+/**
+ * qcrypto_random_bytes:
+ * @buf: the buffer to fill
+ * @buflen: length of @buf in bytes
+ * @errp: pointer to a NULL-initialized error object
+ *
+ * Fill @buf with @buflen bytes of cryptographically strong
+ * random data
+ *
+ * Returns 0 on sucess, -1 on error
+ */
+int qcrypto_random_bytes(uint8_t *buf,
+                         size_t buflen,
+                         Error **errp);
+
+
+#endif /* QCRYPTO_RANDOM_H__ */