[libvirt] [PATCH 07/10] virRandomBytes: Use gnutls_rnd whenever possible

[Michal Privoznik]

While /dev/urandom is not terrible source of random data
gnutls_rnd is better. Prefer that one.

Also, since nearly every platform we build on already has gnutls
(if not all of them) this is going to be used by default.

Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
---
 src/util/vircrypto.c | 20 +-------------------
 src/util/virrandom.c | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+), 19 deletions(-)

diff --git a/src/util/vircrypto.c b/src/util/vircrypto.c
index e5f2319720..3f3ba0267a 100644
--- a/src/util/vircrypto.c
+++ b/src/util/vircrypto.c
@@ -330,23 +330,5 @@ int
 virCryptoGenerateRandom(unsigned char *buf,
                         size_t buflen)
 {
-#if WITH_GNUTLS
-    int rv;
-
-    /* Generate the byte stream using gnutls_rnd() if possible */
-    if ((rv = gnutls_rnd(GNUTLS_RND_RANDOM, buf, buflen)) < 0) {
-        virReportError(VIR_ERR_INTERNAL_ERROR,
-                       _("failed to generate byte stream: %s"),
-                       gnutls_strerror(rv));
-        return -1;
-    }
-#else
-    /* If we don't have gnutls_rnd(), we will generate a less cryptographically
-     * strong master buf from /dev/urandom.
-     */
-    if (virRandomBytes(buf, buflen) < 0)
-        return -1;
-#endif
-
-    return 0;
+    return virRandomBytes(buf, buflen);
 }
diff --git a/src/util/virrandom.c b/src/util/virrandom.c
index 230745d311..444b0f9802 100644
--- a/src/util/virrandom.c
+++ b/src/util/virrandom.c
@@ -29,6 +29,10 @@
 #include <fcntl.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+#ifdef WITH_GNUTLS
+# include <gnutls/gnutls.h>
+# include <gnutls/crypto.h>
+#endif
 
 #include "virrandom.h"
 #include "virthread.h"
@@ -175,6 +179,19 @@ int
 virRandomBytes(unsigned char *buf,
                size_t buflen)
 {
+#if WITH_GNUTLS
+    int rv;
+
+    /* Generate the byte stream using gnutls_rnd() if possible */
+    if ((rv = gnutls_rnd(GNUTLS_RND_RANDOM, buf, buflen)) < 0) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("failed to generate byte stream: %s"),
+                       gnutls_strerror(rv));
+        return -1;
+    }
+
+#else /* !WITH_GNUTLS */
+
     int fd;
 
     if ((fd = open(RANDOM_SOURCE, O_RDONLY)) < 0) {
@@ -200,6 +217,7 @@ virRandomBytes(unsigned char *buf,
     }
 
     VIR_FORCE_CLOSE(fd);
+#endif /* !WITH_GNUTLS */
 
     return 0;
 }
-- 
2.16.1