random: Fix rndgetentropy correctly uses rndjent.

* random/rndgetentropy.c (_gcry_rndgetentropy_gather_random): Call
_gcry_rndjent_poll for GCRY_VERY_STRONG_RANDOM.

--

GnuPG-bug-id: 5692
Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>

1 files changed, 14 insertions, 2 deletions

diff --git a/random/rndgetentropy.c b/random/rndgetentropy.c
index 5a033276..a64b7299 100644
--- a/random/rndgetentropy.c
+++ b/random/rndgetentropy.c
@@ -41,8 +41,6 @@ _gcry_rndgetentropy_gather_random (void (*add)(const void*, size_t,
 {
   byte buffer[256];
 
-  (void)level;
-
   if (!add)
     {
       /* Special mode to release resouces.  */
@@ -50,6 +48,20 @@ _gcry_rndgetentropy_gather_random (void (*add)(const void*, size_t,
       return 0;
     }
 
+  /* When using a blocking random generator try to get some entropy
+   * from the jitter based RNG.  In this case we take up to 50% of the
+   * remaining requested bytes.  */
+  if (level >= GCRY_VERY_STRONG_RANDOM)
+    {
+      size_t n;
+
+      n = _gcry_rndjent_poll (add, origin, length/2);
+      if (n > length/2)
+        n = length/2;
+      if (length > 1)
+        length -= n;
+    }
+
   /* Enter the loop.  */
   while (length)
     {