File openssh-7.2p2-seed-prng.patch of Package openssh.29886
From f0cecf263004f2ee4acadf72345c7cc9e5b20afa Mon Sep 17 00:00:00 2001
From: Old openssh patches <pcerny@suse.com>
Date: Wed, 26 Oct 2022 09:50:38 +0200
Subject: [PATCH] openssh-7.2p2-seed-prng
# HG changeset patch
# Parent 84a8ae72aaf1527a30b037965dce9dfe4c517c29
# extended support for (re-)seeding the OpenSSL PRNG from /dev/random
# bnc#703221, FATE#312172
---
entropy.c | 4 ++
openbsd-compat/Makefile.in | 2 +-
openbsd-compat/port-linux-prng.c | 81 ++++++++++++++++++++++++++++++++
openbsd-compat/port-linux.h | 4 ++
ssh-add.1 | 14 ++++++
ssh-agent.1 | 17 +++++++
ssh-keygen.1 | 17 +++++++
ssh-keysign.8 | 17 +++++++
ssh.1 | 14 ++++++
sshd.8 | 17 +++++++
sshd.c | 13 +++++
11 files changed, 199 insertions(+), 1 deletion(-)
create mode 100644 openbsd-compat/port-linux-prng.c
diff --git a/entropy.c b/entropy.c
index 9305f89a..a373325c 100644
--- a/entropy.c
+++ b/entropy.c
@@ -54,6 +54,7 @@
#include "pathnames.h"
#include "log.h"
#include "buffer.h"
+#include "openbsd-compat/port-linux.h"
/*
* Portable OpenSSH PRNG seeding:
@@ -229,6 +230,9 @@ seed_rng(void)
memset(buf, '\0', sizeof(buf));
#endif /* OPENSSL_PRNG_ONLY */
+
+ linux_seed();
+
if (RAND_status() != 1)
fatal("PRNG is not seeded");
}
diff --git a/openbsd-compat/Makefile.in b/openbsd-compat/Makefile.in
index 3c5e3b7f..b4e0da8f 100644
--- a/openbsd-compat/Makefile.in
+++ b/openbsd-compat/Makefile.in
@@ -20,7 +20,7 @@ OPENBSD=base64.o basename.o bcrypt_pbkdf.o bindresvport.o blowfish.o daemon.o di
COMPAT=arc4random.o bsd-asprintf.o bsd-closefrom.o bsd-cray.o bsd-cygwin_util.o bsd-getpeereid.o getrrsetbyname-ldns.o bsd-misc.o bsd-nextstep.o bsd-openpty.o bsd-poll.o bsd-setres_id.o bsd-snprintf.o bsd-statvfs.o bsd-waitpid.o fake-rfc2553.o openssl-compat.o xmmap.o xcrypt.o kludge-fd_set.o
-PORTS=port-aix.o port-irix.o port-linux.o port-solaris.o port-tun.o port-uw.o
+PORTS=port-aix.o port-irix.o port-linux.o port-linux-prng.o port-solaris.o port-tun.o port-uw.o
.c.o:
$(CC) $(CFLAGS) $(CPPFLAGS) -c $<
diff --git a/openbsd-compat/port-linux-prng.c b/openbsd-compat/port-linux-prng.c
new file mode 100644
index 00000000..dfc4bdba
--- /dev/null
+++ b/openbsd-compat/port-linux-prng.c
@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 2011 Jan F. Chadima <jchadima@redhat.com>
+ * (c) 2011 Petr Cerny <pcerny@suse.cz>
+ *
+ * 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 "defines.h"
+
+#include <errno.h>
+#include <stdarg.h>
+#include <string.h>
+#include <stdio.h>
+#include <openssl/rand.h>
+
+#include "log.h"
+#include "port-linux.h"
+#include "fips.h"
+
+#define RNG_BYTES_DEFAULT 6L
+#define RNG_ENV_VAR "SSH_USE_STRONG_RNG"
+
+long rand_bytes = 0;
+char *rand_file = NULL;
+
+static void
+linux_seed_init(void)
+{
+ long elen = 0;
+ char *env = getenv(RNG_ENV_VAR);
+
+ if (env) {
+ errno = 0;
+ elen = strtol(env, NULL, 10);
+ if (errno) {
+ elen = RNG_BYTES_DEFAULT;
+ debug("bogus value in the %s environment variable, "
+ "using %li bytes from /dev/random\n",
+ RNG_ENV_VAR, RNG_BYTES_DEFAULT);
+ }
+ }
+
+ if (elen || fips_mode())
+ rand_file = "/dev/random";
+ else
+ rand_file = "/dev/urandom";
+
+ rand_bytes = MAX(elen, RNG_BYTES_DEFAULT);
+}
+
+void
+linux_seed(void)
+{
+ long len;
+ if (!rand_file)
+ linux_seed_init();
+
+ errno = 0;
+ len = RAND_load_file(rand_file, rand_bytes);
+ if (len != rand_bytes) {
+ if (errno)
+ fatal ("cannot read from %s, %s", rand_file, strerror(errno));
+ else
+ fatal ("EOF reading %s", rand_file);
+ }
+}
diff --git a/openbsd-compat/port-linux.h b/openbsd-compat/port-linux.h
index e3d1004a..e4ebffc5 100644
--- a/openbsd-compat/port-linux.h
+++ b/openbsd-compat/port-linux.h
@@ -19,6 +19,10 @@
#ifndef _PORT_LINUX_H
#define _PORT_LINUX_H
+extern long rand_bytes;
+extern char *rand_file;
+void linux_seed(void);
+
#ifdef WITH_SELINUX
int ssh_selinux_enabled(void);
void ssh_selinux_setup_pty(char *, const char *);
diff --git a/ssh-add.1 b/ssh-add.1
index f02b595d..316e225e 100644
--- a/ssh-add.1
+++ b/ssh-add.1
@@ -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 6 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 --git a/ssh-agent.1 b/ssh-agent.1
index c4b50bbd..814c8639 100644
--- a/ssh-agent.1
+++ b/ssh-agent.1
@@ -201,6 +201,23 @@ sockets used to contain the connection to the authentication agent.
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 6 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.
.Sh SEE ALSO
.Xr ssh 1 ,
.Xr ssh-add 1 ,
diff --git a/ssh-keygen.1 b/ssh-keygen.1
index 37a4fc2b..46941fd1 100644
--- a/ssh-keygen.1
+++ b/ssh-keygen.1
@@ -846,6 +846,23 @@ Contains Diffie-Hellman groups used for DH-GEX.
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 6 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.
.Sh SEE ALSO
.Xr ssh 1 ,
.Xr ssh-add 1 ,
diff --git a/ssh-keysign.8 b/ssh-keysign.8
index 19b0dbc5..639b56ee 100644
--- a/ssh-keysign.8
+++ b/ssh-keysign.8
@@ -80,6 +80,23 @@ must be set-uid root if host-based authentication is used.
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 6 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.
.Sh SEE ALSO
.Xr ssh 1 ,
.Xr ssh-keygen 1 ,
diff --git a/ssh.1 b/ssh.1
index cc533433..7ce39a3f 100644
--- a/ssh.1
+++ b/ssh.1
@@ -1416,6 +1416,20 @@ For more information, see the
.Cm PermitUserEnvironment
option in
.Xr sshd_config 5 .
+.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 6 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.
.Sh FILES
.Bl -tag -width Ds -compact
.It Pa ~/.rhosts
diff --git a/sshd.8 b/sshd.8
index cf27e826..dce962e9 100644
--- a/sshd.8
+++ b/sshd.8
@@ -977,6 +977,23 @@ concurrently for different ports, this contains the process ID of the one
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 6 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.
.Sh SEE ALSO
.Xr scp 1 ,
.Xr sftp 1 ,
diff --git a/sshd.c b/sshd.c
index 73c5ec1a..8d3a42d9 100644
--- a/sshd.c
+++ b/sshd.c
@@ -55,6 +55,8 @@
#endif
#include "openbsd-compat/sys-tree.h"
#include "openbsd-compat/sys-queue.h"
+#include "openbsd-compat/port-linux.h"
+
#include <sys/wait.h>
#include <errno.h>
@@ -213,6 +215,13 @@ struct {
u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH];
} sensitive_data;
+/*
+ * Every RESEED_AFTERth connection triggers call to linux_seed() to re-seed the
+ * random pool.
+ */
+#define RESEED_AFTER 100
+static int re_seeding_counter = RESEED_AFTER;
+
/*
* Flag indicating whether the RSA server key needs to be regenerated.
* Is set in the SIGALRM handler and cleared when the key is regenerated.
@@ -1348,6 +1357,10 @@ server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
startups++;
break;
}
+ if(!(--re_seeding_counter)) {
+ re_seeding_counter = RESEED_AFTER;
+ linux_seed();
+ }
/*
* Got connection. Fork a child to handle it, unless
--
2.38.0
