diff -up openssh-7.4p1/entropy.c.entropy openssh-7.4p1/entropy.c

--- openssh-7.4p1/entropy.c.entropy	2016-12-19 05:59:41.000000000 +0100

+++ openssh-7.4p1/entropy.c	2016-12-23 18:34:27.769753570 +0100

@@ -229,6 +229,9 @@ seed_rng(void)

 	memset(buf, '\0', sizeof(buf));

 #endif /* OPENSSL_PRNG_ONLY */

+#ifdef __linux__

+	linux_seed();

+#endif /* __linux__ */

 	if (RAND_status() != 1)

 		fatal("PRNG is not seeded");

 }

diff -up openssh-7.4p1/openbsd-compat/Makefile.in.entropy openssh-7.4p1/openbsd-compat/Makefile.in

--- openssh-7.4p1/openbsd-compat/Makefile.in.entropy	2016-12-23 18:34:53.715762155 +0100

+++ openssh-7.4p1/openbsd-compat/Makefile.in	2016-12-23 18:35:15.890769493 +0100

@@ -20,7 +20,8 @@ OPENBSD=base64.o basename.o bcrypt_pbkdf

 	port-solaris.o \

 	port-net.o \

 	port-uw.o \

-	port-linux-sshd.o

+	port-linux-sshd.o \

+	port-linux-prng.o

 .c.o:

 	$(CC) $(CFLAGS) $(CPPFLAGS) -c $<

diff -up openssh-7.4p1/openbsd-compat/port-linux.h.entropy openssh-7.4p1/openbsd-compat/port-linux.h

--- openssh-7.4p1/openbsd-compat/port-linux.h.entropy	2016-12-23 18:34:27.747753563 +0100

+++ openssh-7.4p1/openbsd-compat/port-linux.h	2016-12-23 18:34:27.769753570 +0100

@@ -34,4 +34,6 @@ void oom_adjust_restore(void);

 void oom_adjust_setup(void);

 #endif

+void linux_seed(void);

+

 #endif /* ! _PORT_LINUX_H */

diff -up openssh-7.4p1/openbsd-compat/port-linux-prng.c.entropy openssh-7.4p1/openbsd-compat/port-linux-prng.c

--- openssh-7.4p1/openbsd-compat/port-linux-prng.c.entropy	2016-12-23 18:34:27.769753570 +0100

+++ openssh-7.4p1/openbsd-compat/port-linux-prng.c	2016-12-23 18:34:27.769753570 +0100

@@ -0,0 +1,59 @@

+/* $Id: port-linux.c,v 1.11.4.2 2011/02/04 00:43:08 djm Exp $ */

+

+/*

+ * Copyright (c) 2011 Jan F. Chadima <jchadima@redhat.com>

+ *

+ * 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.

+ */

+

+/*

+ * Linux-specific portability code - prng support

+ */

+

+#include "includes.h"

+

+#include <errno.h>

+#include <stdarg.h>

+#include <string.h>

+#include <stdio.h>

+#include <openssl/rand.h>

+

+#include "log.h"

+#include "xmalloc.h"

+#include "misc.h"      /* servconf.h needs misc.h for struct ForwardOptions */

+#include "servconf.h"

+#include "port-linux.h"

+#include "key.h"

+#include "hostfile.h"

+#include "auth.h"

+

+void

+linux_seed(void)

+{

+	char *env = getenv("SSH_USE_STRONG_RNG");

+	char *random = "/dev/random";

+	size_t len, ienv, randlen = 14;

+

+	if (!env || !strcmp(env, "0"))

+		random = "/dev/urandom";

+	else if ((ienv = atoi(env)) > randlen)

+		randlen = ienv;

+

+	errno = 0;

+	if ((len = RAND_load_file(random, randlen)) != randlen) {

+		if (errno)

+			fatal ("cannot read from %s, %s", random, strerror(errno));

+		else

+			fatal ("EOF reading %s", random);

+	}

+}

diff -up openssh-7.4p1/ssh.1.entropy openssh-7.4p1/ssh.1

--- openssh-7.4p1/ssh.1.entropy	2016-12-23 18:34:27.754753565 +0100

+++ openssh-7.4p1/ssh.1	2016-12-23 18:34:27.770753571 +0100

@@ -1441,6 +1441,23 @@ For more information, see the

 .Cm PermitUserEnvironment

 option in

 .Xr sshd_config 5 .

+.Sh ENVIRONMENT

+.Bl -tag -width Ds -compact

+.It Ev SSH_USE_STRONG_RNG

+The reseeding of the OpenSSL random generator is usually done from

+.Cm /dev/urandom .

+If the 

+.Cm SSH_USE_STRONG_RNG

+environment variable is set to value other than

+.Cm 0

+the OpenSSL random generator is reseeded from

+.Cm /dev/random .

+The number of bytes read is defined by the SSH_USE_STRONG_RNG value. 

+Minimum is 14 bytes.

+This setting is not recommended on the computers without the hardware

+random generator because insufficient entropy causes the connection to 

+be blocked until enough entropy is available.

+.El

 .Sh FILES

 .Bl -tag -width Ds -compact

 .It Pa ~/.rhosts

diff -up openssh-7.4p1/ssh-add.1.entropy openssh-7.4p1/ssh-add.1

--- openssh-7.4p1/ssh-add.1.entropy	2016-12-19 05:59:41.000000000 +0100

+++ openssh-7.4p1/ssh-add.1	2016-12-23 18:34:27.770753571 +0100

@@ -171,6 +171,20 @@ to make this work.)

 Identifies the path of a

 .Ux Ns -domain

 socket used to communicate with the agent.

+.It Ev SSH_USE_STRONG_RNG

+The reseeding of the OpenSSL random generator is usually done from

+.Cm /dev/urandom .

+If the 

+.Cm SSH_USE_STRONG_RNG

+environment variable is set to value other than

+.Cm 0

+the OpenSSL random generator is reseeded from

+.Cm /dev/random .

+The number of bytes read is defined by the SSH_USE_STRONG_RNG value. 

+Minimum is 14 bytes.

+This setting is not recommended on the computers without the hardware

+random generator because insufficient entropy causes the connection to 

+be blocked until enough entropy is available.

 .El

 .Sh FILES

 .Bl -tag -width Ds

diff -up openssh-7.4p1/ssh-agent.1.entropy openssh-7.4p1/ssh-agent.1

--- openssh-7.4p1/ssh-agent.1.entropy	2016-12-19 05:59:41.000000000 +0100

+++ openssh-7.4p1/ssh-agent.1	2016-12-23 18:34:27.770753571 +0100

@@ -214,6 +214,24 @@ sockets used to contain the connection t

 These sockets should only be readable by the owner.

 The sockets should get automatically removed when the agent exits.

 .El

+.Sh ENVIRONMENT

+.Bl -tag -width Ds -compact

+.Pp

+.It Pa SSH_USE_STRONG_RNG

+The reseeding of the OpenSSL random generator is usually done from

+.Cm /dev/urandom .

+If the 

+.Cm SSH_USE_STRONG_RNG

+environment variable is set to value other than

+.Cm 0

+the OpenSSL random generator is reseeded from

+.Cm /dev/random .

+The number of bytes read is defined by the SSH_USE_STRONG_RNG value. 

+Minimum is 14 bytes.

+This setting is not recommended on the computers without the hardware

+random generator because insufficient entropy causes the connection to 

+be blocked until enough entropy is available.

+.El

 .Sh SEE ALSO

 .Xr ssh 1 ,

 .Xr ssh-add 1 ,

diff -up openssh-7.4p1/sshd.8.entropy openssh-7.4p1/sshd.8

--- openssh-7.4p1/sshd.8.entropy	2016-12-23 18:34:27.755753566 +0100

+++ openssh-7.4p1/sshd.8	2016-12-23 18:34:27.770753571 +0100

@@ -920,6 +920,24 @@ concurrently for different ports, this c

 started last).

 The content of this file is not sensitive; it can be world-readable.

 .El

+.Sh ENVIRONMENT

+.Bl -tag -width Ds -compact

+.Pp

+.It Pa SSH_USE_STRONG_RNG

+The reseeding of the OpenSSL random generator is usually done from

+.Cm /dev/urandom .

+If the 

+.Cm SSH_USE_STRONG_RNG

+environment variable is set to value other than

+.Cm 0

+the OpenSSL random generator is reseeded from

+.Cm /dev/random .

+The number of bytes read is defined by the SSH_USE_STRONG_RNG value. 

+Minimum is 14 bytes.

+This setting is not recommended on the computers without the hardware

+random generator because insufficient entropy causes the connection to 

+be blocked until enough entropy is available.

+.El

 .Sh IPV6

 IPv6 address can be used everywhere where IPv4 address. In all entries must be the IPv6 address enclosed in square brackets. Note: The square brackets are metacharacters for the shell and must be escaped in shell.

 .Sh SEE ALSO

diff -up openssh-7.4p1/ssh-keygen.1.entropy openssh-7.4p1/ssh-keygen.1

--- openssh-7.4p1/ssh-keygen.1.entropy	2016-12-19 05:59:41.000000000 +0100

+++ openssh-7.4p1/ssh-keygen.1	2016-12-23 18:34:27.770753571 +0100

@@ -848,6 +848,24 @@ Contains Diffie-Hellman groups used for

 The file format is described in

 .Xr moduli 5 .

 .El

+.Sh ENVIRONMENT

+.Bl -tag -width Ds -compact

+.Pp

+.It Pa SSH_USE_STRONG_RNG

+The reseeding of the OpenSSL random generator is usually done from

+.Cm /dev/urandom .

+If the 

+.Cm SSH_USE_STRONG_RNG

+environment variable is set to value other than

+.Cm 0

+the OpenSSL random generator is reseeded from

+.Cm /dev/random .

+The number of bytes read is defined by the SSH_USE_STRONG_RNG value. 

+Minimum is 14 bytes.

+This setting is not recommended on the computers without the hardware

+random generator because insufficient entropy causes the connection to 

+be blocked until enough entropy is available.

+.El

 .Sh SEE ALSO

 .Xr ssh 1 ,

 .Xr ssh-add 1 ,

diff -up openssh-7.4p1/ssh-keysign.8.entropy openssh-7.4p1/ssh-keysign.8

--- openssh-7.4p1/ssh-keysign.8.entropy	2016-12-19 05:59:41.000000000 +0100

+++ openssh-7.4p1/ssh-keysign.8	2016-12-23 18:34:27.770753571 +0100

@@ -80,6 +80,24 @@ must be set-uid root if host-based authe

 If these files exist they are assumed to contain public certificate

 information corresponding with the private keys above.

 .El

+.Sh ENVIRONMENT

+.Bl -tag -width Ds -compact

+.Pp

+.It Pa SSH_USE_STRONG_RNG

+The reseeding of the OpenSSL random generator is usually done from

+.Cm /dev/urandom .

+If the 

+.Cm SSH_USE_STRONG_RNG

+environment variable is set to value other than

+.Cm 0

+the OpenSSL random generator is reseeded from

+.Cm /dev/random .

+The number of bytes read is defined by the SSH_USE_STRONG_RNG value. 

+Minimum is 14 bytes.

+This setting is not recommended on the computers without the hardware

+random generator because insufficient entropy causes the connection to 

+be blocked until enough entropy is available.

+.El

 .Sh SEE ALSO

 .Xr ssh 1 ,

 .Xr ssh-keygen 1 ,