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From 8c59bae0e4bdc0e3456d1802b391370bdf9975f3 Mon Sep 17 00:00:00 2001
From: mancha <mancha1 AT zoho DOT com>
Date: Mon, 6 Oct 2014
Subject: Re-introduce TCP Wrappers support
Support for TCP Wrappers was dropped as of OpenSSH 6.7. This patch
resurrects the feature.
Relevant upstream commits:
https://anongit.mindrot.org/openssh.git/commit/?id=f2719b7c2b8a
https://anongit.mindrot.org/openssh.git/commit/?id=f9696566fb41
---
configure.ac | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++++
sshd.8 | 7 +++++++
sshd.c | 25 +++++++++++++++++++++++
3 files changed, 89 insertions(+)
--- a/configure.ac
+++ b/configure.ac
@@ -1380,6 +1380,62 @@ AC_ARG_WITH([skey],
]
)
+# Check whether user wants TCP wrappers support
+TCPW_MSG="no"
+AC_ARG_WITH([tcp-wrappers],
+ [ --with-tcp-wrappers[[=PATH]] Enable tcpwrappers support (optionally in PATH)],
+ [
+ if test "x$withval" != "xno" ; then
+ saved_LIBS="$LIBS"
+ saved_LDFLAGS="$LDFLAGS"
+ saved_CPPFLAGS="$CPPFLAGS"
+ if test -n "${withval}" && \
+ test "x${withval}" != "xyes"; then
+ if test -d "${withval}/lib"; then
+ if test -n "${need_dash_r}"; then
+ LDFLAGS="-L${withval}/lib -R${withval}/lib ${LDFLAGS}"
+ else
+ LDFLAGS="-L${withval}/lib ${LDFLAGS}"
+ fi
+ else
+ if test -n "${need_dash_r}"; then
+ LDFLAGS="-L${withval} -R${withval} ${LDFLAGS}"
+ else
+ LDFLAGS="-L${withval} ${LDFLAGS}"
+ fi
+ fi
+ if test -d "${withval}/include"; then
+ CPPFLAGS="-I${withval}/include ${CPPFLAGS}"
+ else
+ CPPFLAGS="-I${withval} ${CPPFLAGS}"
+ fi
+ fi
+ LIBS="-lwrap -lnsl $LIBS"
+ AC_MSG_CHECKING([for libwrap])
+ AC_LINK_IFELSE([AC_LANG_PROGRAM([[
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <tcpd.h>
+int deny_severity = 0, allow_severity = 0;
+ ]], [[
+ hosts_access(0);
+ ]])], [
+ AC_MSG_RESULT([yes])
+ AC_DEFINE([LIBWRAP], [1],
+ [Define if you want
+ TCP Wrappers support])
+ SSHDLIBS="$SSHDLIBS -lwrap -lnsl"
+ TCPW_MSG="yes"
+ ], [
+ AC_MSG_ERROR([*** libwrap missing])
+
+ ])
+ LIBS="$saved_LIBS"
+ fi
+ ]
+)
+
# Check whether user wants to use ldns
LDNS_MSG="no"
AC_ARG_WITH(ldns,
@@ -4829,6 +4885,7 @@ echo " KerberosV support
echo " SELinux support: $SELINUX_MSG"
echo " Smartcard support: $SCARD_MSG"
echo " S/KEY support: $SKEY_MSG"
+echo " TCP Wrappers support: $TCPW_MSG"
echo " MD5 password support: $MD5_MSG"
echo " libedit support: $LIBEDIT_MSG"
echo " Solaris process contract support: $SPC_MSG"
--- a/sshd.8
+++ b/sshd.8
@@ -851,6 +851,12 @@ the user's home directory becomes access
This file should be writable only by the user, and need not be
readable by anyone else.
.Pp
+.It Pa /etc/hosts.allow
+.It Pa /etc/hosts.deny
+Access controls that should be enforced by tcp-wrappers are defined here.
+Further details are described in
+.Xr hosts_access 5 .
+.Pp
.It Pa /etc/hosts.equiv
This file is for host-based authentication (see
.Xr ssh 1 ) .
@@ -954,6 +960,7 @@ The content of this file is not sensitiv
.Xr ssh-keygen 1 ,
.Xr ssh-keyscan 1 ,
.Xr chroot 2 ,
+.Xr hosts_access 5 ,
.Xr login.conf 5 ,
.Xr moduli 5 ,
.Xr sshd_config 5 ,
--- a/sshd.c
+++ b/sshd.c
@@ -123,6 +123,13 @@
#include "ssh-sandbox.h"
#include "version.h"
+#ifdef LIBWRAP
+#include <tcpd.h>
+#include <syslog.h>
+int allow_severity;
+int deny_severity;
+#endif /* LIBWRAP */
+
#ifndef O_NOCTTY
#define O_NOCTTY 0
#endif
@@ -2054,6 +2061,24 @@ main(int ac, char **av)
#ifdef SSH_AUDIT_EVENTS
audit_connection_from(remote_ip, remote_port);
#endif
+#ifdef LIBWRAP
+ allow_severity = options.log_facility|LOG_INFO;
+ deny_severity = options.log_facility|LOG_WARNING;
+ /* Check whether logins are denied from this host. */
+ if (packet_connection_is_on_socket()) {
+ struct request_info req;
+
+ request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0);
+ fromhost(&req);
+
+ if (!hosts_access(&req)) {
+ debug("Connection refused by tcp wrapper");
+ refuse(&req);
+ /* NOTREACHED */
+ fatal("libwrap refuse returns");
+ }
+ }
+#endif /* LIBWRAP */
/* Log the connection. */
verbose("Connection from %s port %d on %s port %d",
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