Replace the old OpenSSL PRNG by direct use of arc4random_buf(), keeping the

existing RAND interfaces unchanged.

All interfaces allowing external feed or seed of the RNG (either from a file
or a local entropy gathering daemon) are kept for ABI compatibility, but are
no longer do anything.

While the OpenSSL PRNG was required 15+ years ago when many systems lacked
proper entropy collection, things have evolved and one can reasonably assume
it is better to use the kernel (system global) entropy pool rather than trying
to build one's own and having to compensate for thread scheduling...

<RANT>
Whoever thought that RAND_screen(), feeding the PRNG with the contents of the
local workstation's display, under Win32, was a smart idea, ought to be banned
from security programming.
</RANT>

ok beck@ deraadt@ tedu@

1 files changed, 44 insertions, 0 deletions

diff --git a/src/lib/libcrypto/rand/rc4_rand.c b/src/lib/libcrypto/rand/rc4_rand.c
new file mode 100644
index 0000000000..ebfb241d53
--- /dev/null
+++ b/src/lib/libcrypto/rand/rc4_rand.c
@@ -0,0 +1,44 @@
+/*      $OpenBSD: rc4_rand.c,v 1.1 2014/04/15 16:52:50 miod Exp $       */
+
+/*
+ * Copyright (c) 2014 Miodrag Vallat.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <stdlib.h>
+
+#include <openssl/rand.h>
+
+static int
+arc4_rand_bytes(unsigned char *buf, int num)
+{
+        if (num > 0)
+                arc4random_buf(buf, (size_t)num);
+
+        return 1;
+}
+
+static RAND_METHOD rand_arc4_meth = {
+        .seed = NULL,           /* no external seed allowed */
+        .bytes = arc4_rand_bytes,
+        .cleanup = NULL,        /* no cleanup necessary */
+        .add = NULL,            /* no external feed allowed */
+        .pseudorand = arc4_rand_bytes,
+        .status = NULL          /* no possible error condition */
+};
+
+RAND_METHOD *RAND_SSLeay(void)
+{
+        return &rand_arc4_meth;
+}