Restore TCP wrappers support

Support for TCP wrappers was dropped in OpenSSH 6.7.  See this message
and thread:

  https://lists.mindrot.org/pipermail/openssh-unix-dev/2014-April/032497.html

It is true that this reduces preauth attack surface in sshd.  On the
other hand, this support seems to be quite widely used, and abruptly
dropping it (from the perspective of users who don't read
openssh-unix-dev) could easily cause more serious problems in practice.

It's not entirely clear what the right long-term answer for Debian is,
but it at least probably doesn't involve dropping this feature shortly
before a freeze.

Forwarded: not-needed
Last-Update: 2019-06-05

Patch-Name: restore-tcp-wrappers.patch

1 files changed, 57 insertions, 0 deletions

diff --git a/configure.ac b/configure.ac
index d98e6f74a..812b7218f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1558,6 +1558,62 @@ else
         AC_MSG_RESULT([no])
 fi
 
+# 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 $LIBS"
+                        AC_MSG_CHECKING([for libwrap])
+                        AC_LINK_IFELSE([AC_LANG_PROGRAM([[
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <tcpd.h>
+int deny_severity = 0, allow_severity = 0;
+                                ]], [[
+        hosts_access(0);
+                                ]])], [
+                                        AC_MSG_RESULT([yes])
+                                        AC_DEFINE([LIBWRAP], [1],
+                                                [Define if you want
+                                                TCP Wrappers support])
+                                        SSHDLIBS="$SSHDLIBS -lwrap"
+                                        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,
@@ -5479,6 +5535,7 @@ echo "                       PAM support: $PAM_MSG"
 echo "                   OSF SIA support: $SIA_MSG"
 echo "                 KerberosV support: $KRB5_MSG"
 echo "                   SELinux support: $SELINUX_MSG"
+echo "              TCP Wrappers support: $TCPW_MSG"
 echo "              MD5 password support: $MD5_MSG"
 echo "                   libedit support: $LIBEDIT_MSG"
 echo "                   libldns support: $LDNS_MSG"