[Buildroot] [PATCH 2/4] package/openssh: improve integration for systemd

Jérémy ROSEN jeremy.rosen at smile.fr
Sun Jun 7 19:16:29 UTC 2020


Le dim. 7 juin 2020 à 21:03, Norbert Lange <nolange79 at gmail.com> a écrit :

> Am So., 7. Juni 2020 um 12:54 Uhr schrieb Jérémy ROSEN <
> jeremy.rosen at smile.fr>:
> >
> >
> >
> > Le sam. 6 juin 2020 à 00:59, Norbert Lange <nolange79 at gmail.com> a
> écrit :
> >>
> >> the openssh daemon is not suited for systemd's simple
> >> service type. dependend services should only start
> >> when sshd is ready to accept connections.
> >>
> >> A patch is added from debian to allow openssh
> >> to communicate this state.
> >>
> >> Restarts are prevented if the reason is a faulty
> >> config file (errocode 255).
> >>
> >> The "user confinement directory" is changed to
> >> '/run/sshd' which is automatically managed by systemd.
> >>
> >> Signed-off-by: Norbert Lange <nolange79 at gmail.com>
> >> ---
> >>  package/openssh/00-systemd-readiness.patch | 84 ++++++++++++++++++++++
> >>  package/openssh/openssh.mk                 | 14 +++-
> >>  package/openssh/sshd-sysusers.conf         |  2 +-
> >>  package/openssh/sshd.service               | 13 +++-
> >>  4 files changed, 109 insertions(+), 4 deletions(-)
> >>  create mode 100644 package/openssh/00-systemd-readiness.patch
> >>
> >> diff --git a/package/openssh/00-systemd-readiness.patch
> b/package/openssh/00-systemd-readiness.patch
> >> new file mode 100644
> >> index 0000000000..be3b6b0074
> >> --- /dev/null
> >> +++ b/package/openssh/00-systemd-readiness.patch
> >> @@ -0,0 +1,84 @@
> >> +From ab765b2bd55062a704f09da8f8c1c4ad1d6630a7 Mon Sep 17 00:00:00 2001
> >> +From: Michael Biebl <biebl at debian.org>
> >> +Date: Mon, 21 Dec 2015 16:08:47 +0000
> >> +Subject: Add systemd readiness notification support
> >> +
> >> +Bug-Debian: https://bugs.debian.org/778913
> >> +Forwarded: no
> >> +Last-Update: 2017-08-22
> >> +
> >> +Patch-Name: systemd-readiness.patch
> >> +---
> >> + configure.ac | 24 ++++++++++++++++++++++++
> >> + sshd.c       |  9 +++++++++
> >> + 2 files changed, 33 insertions(+)
> >> +
> >> +diff --git a/configure.ac b/configure.ac
> >> +index e894db9fc..c119d6fd1 100644
> >> +--- a/configure.ac
> >> ++++ b/configure.ac
> >> +@@ -4499,6 +4499,29 @@ AC_ARG_WITH([kerberos5],
> >> + AC_SUBST([GSSLIBS])
> >> + AC_SUBST([K5LIBS])
> >> +
> >> ++# Check whether user wants systemd support
> >> ++SYSTEMD_MSG="no"
> >> ++AC_ARG_WITH(systemd,
> >> ++      [  --with-systemd          Enable systemd support],
> >> ++      [ if test "x$withval" != "xno" ; then
> >> ++              AC_PATH_TOOL([PKGCONFIG], [pkg-config], [no])
> >> ++              if test "$PKGCONFIG" != "no"; then
> >> ++                      AC_MSG_CHECKING([for libsystemd])
> >> ++                      if $PKGCONFIG --exists libsystemd; then
> >> ++                              SYSTEMD_CFLAGS=`$PKGCONFIG --cflags
> libsystemd`
> >> ++                              SYSTEMD_LIBS=`$PKGCONFIG --libs
> libsystemd`
> >> ++                              CPPFLAGS="$CPPFLAGS $SYSTEMD_CFLAGS"
> >> ++                              SSHDLIBS="$SSHDLIBS $SYSTEMD_LIBS"
> >> ++                              AC_MSG_RESULT([yes])
> >> ++                              AC_DEFINE(HAVE_SYSTEMD, 1, [Define if
> you want systemd support.])
> >> ++                              SYSTEMD_MSG="yes"
> >> ++                      else
> >> ++                              AC_MSG_RESULT([no])
> >> ++                      fi
> >> ++              fi
> >> ++      fi ]
> >> ++)
> >> ++
> >> + # Looking for programs, paths and files
> >> +
> >> + PRIVSEP_PATH=/var/empty
> >> +@@ -5305,6 +5328,7 @@ echo "                   libldns support:
> $LDNS_MSG"
> >> + echo "  Solaris process contract support: $SPC_MSG"
> >> + echo "           Solaris project support: $SP_MSG"
> >> + echo "         Solaris privilege support: $SPP_MSG"
> >> ++echo "                   systemd support: $SYSTEMD_MSG"
> >> + echo "       IP address in \$DISPLAY hack: $DISPLAY_HACK_MSG"
> >> + echo "           Translate v4 in v6 hack: $IPV4_IN6_HACK_MSG"
> >> + echo "                  BSD Auth support: $BSD_AUTH_MSG"
> >> +diff --git a/sshd.c b/sshd.c
> >> +index 4e8ff0662..5e7679a33 100644
> >> +--- a/sshd.c
> >> ++++ b/sshd.c
> >> +@@ -85,6 +85,10 @@
> >> + #include <prot.h>
> >> + #endif
> >> +
> >> ++#ifdef HAVE_SYSTEMD
> >> ++#include <systemd/sd-daemon.h>
> >> ++#endif
> >> ++
> >> + #include "xmalloc.h"
> >> + #include "ssh.h"
> >> + #include "ssh2.h"
> >> +@@ -1951,6 +1955,11 @@ main(int ac, char **av)
> >> +                       }
> >> +               }
> >> +
> >> ++#ifdef HAVE_SYSTEMD
> >> ++              /* Signal systemd that we are ready to accept
> connections */
> >> ++              sd_notify(0, "READY=1");
> >> ++#endif
> >> ++
> >> +               /* Accept a connection and return in a forked child */
> >> +               server_accept_loop(&sock_in, &sock_out,
> >> +                   &newsock, config_s);
> >> diff --git a/package/openssh/openssh.mk b/package/openssh/openssh.mk
> >> index 55b917e20a..d425db1428 100644
> >> --- a/package/openssh/openssh.mk
> >> +++ b/package/openssh/openssh.mk
> >> @@ -12,6 +12,7 @@ OPENSSH_CONF_ENV = \
> >>         LD="$(TARGET_CC)" \
> >>         LDFLAGS="$(TARGET_CFLAGS)" \
> >>         LIBS=`$(PKG_CONFIG_HOST_BINARY) --libs openssl`
> >> +OPENSSH_AUTORECONF = YES
> >>  OPENSSH_CONF_OPTS = \
> >>         --sysconfdir=/etc/ssh \
> >>         --with-default-path=$(BR2_SYSTEM_DEFAULT_PATH) \
> >> @@ -22,9 +23,20 @@ OPENSSH_CONF_OPTS = \
> >>         --disable-wtmpx \
> >>         --disable-strip
> >>
> >> +ifeq ($(BR2_PACKAGE_SYSTEMD),y)
> >> +OPENSSH_DEPENDENCIES = systemd
> >> +
> >> +OPENSSH_CONF_OPTS += \
> >> +       --with-privsep-path=/run/sshd \
> >> +       --with-pid-dir=/run \
> >> +       --with-systemd
> >> +
> >> +else
> >> +
> >>  define OPENSSH_PERMISSIONS
> >>         /var/empty d 755 root root - - - - -
> >>  endef
> >
> >
> > Do we still need this when using systemd, or can it be commented out ?
>
> Not sure what you mean with "this"?
> The OPENSSH_PERMISSIONS block is needed when not using systemd and it
> is only active then.
>
>
my bad, I missed the enclosing ifeq()


> >
> >
> >>
> >> +endif
> >>
> >>  ifeq ($(BR2_TOOLCHAIN_SUPPORTS_PIE),)
> >>  OPENSSH_CONF_OPTS += --without-pie
> >> @@ -72,7 +84,7 @@ define OPENSSH_INSTALL_SYSTEMD_SYSUSERS
> >>  endef
> >>  else
> >>  define OPENSSH_USERS
> >> -       sshd -1 sshd -1 * /var/empty - - SSH drop priv user
> >> +       sshd -1 sshd -1 * $(if
> $(BR2_PACKAGE_SYSTEMD),/run/sshd,/var/empty) - - SSH drop priv user
> >>  endef
> >>  endif
> >>
> >> diff --git a/package/openssh/sshd-sysusers.conf
> b/package/openssh/sshd-sysusers.conf
> >> index ac77aec065..303d0dbb63 100644
> >> --- a/package/openssh/sshd-sysusers.conf
> >> +++ b/package/openssh/sshd-sysusers.conf
> >> @@ -1 +1 @@
> >> -u sshd - "SSH drop priv user" /var/empty
> >> +u sshd - "SSH drop priv user" /run/sshd
> >> diff --git a/package/openssh/sshd.service b/package/openssh/sshd.service
> >> index b5e96b3a25..715bd3f7eb 100644
> >> --- a/package/openssh/sshd.service
> >> +++ b/package/openssh/sshd.service
> >> @@ -1,11 +1,20 @@
> >>  [Unit]
> >>  Description=OpenSSH server daemon
> >> -After=syslog.target network.target auditd.service
> >> +Documentation=man:sshd(8) man:sshd_config(5)
> >> +After=network.target auditd.service
> >>
> >>
> >>  [Service]
> >>  ExecStartPre=/usr/bin/ssh-keygen -A
> >> -ExecStart=/usr/sbin/sshd -D -e
> >> +ExecStartPre=/usr/sbin/sshd -t
> >> +ExecStart=/usr/sbin/sshd -D
> >
> > You droped the -e, so  you are logging to syslog
> > However you droped the dependency on syslog.target earlier...
> > (maybe it should be syslog.socket instead of .target, btw)
>
>
> syslog.target is long long gone, and the syslog will be
> unconditionally available
> https://www.freedesktop.org/wiki/Software/systemd/syslog/
>
>
> >
> >
> > how exactly do you want to log  ? (I think logging to stdout is better,
> it will be
> > redirected to the journal.
>
>
> stdout is not really useful if syslog is supported.
>
> i'd go the other way round

syslog is not really necessary if stdout is available,
but it's a matter of taste :P so let's go your way.


> >
> >
> >>
> >> +ExecReload=/usr/sbin/sshd -t
> >>  ExecReload=/bin/kill -HUP $MAINPID
> >> +KillMode=process
> >
> >
> > Wouldn't mixed be better here ?
> > I'm not really sure what the use-case for procss is anyway...
>
>
> I taken that from debian, I could not argue against it (there is a
> long discussion which I linked above).
> Can you argue *for* mixed?
>
>

I didn't see any link
* process : SIGTERM and SIGKILL is sent only to MainPID
* mixed : SIGTERM is sent to MainPID, SIGKILL is sent to every process in
the service cgroup.

This means that if all works well, they do the same thing

in case the MainPID fails to properly terminate its children, process would
leave children alive
but mixed woul kill everybody

Since we are trying to terminate the service, it makes sense to me to make
sur all child process
are killed.

but I don't see your link so I may be missing something

> >
> >
> >>
> >> +Restart=on-failure
> >> +RestartPreventExitStatus=255
> >> +Type=notify
> >> +RuntimeDirectory=sshd
> >> +RuntimeDirectoryMode=0755
> >>
> >>  [Install]
> >>  WantedBy=multi-user.target
> >> --
> >> 2.26.2
> >>
> >> _______________________________________________
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> >> buildroot at busybox.net
> >> http://lists.busybox.net/mailman/listinfo/buildroot
> >
> >
> >
> > --
> >
> >
> > 20 rue des Jardins
> > 92600 Asnières-sur-Seine
> >
> > Jérémy ROSEN
> > Architecte technique
> >
> >  jeremy.rosen at smile.fr
> >   +33 6 88 25 87 42
> >  http://www.smile.eu
> >
> >
> >
>
> Regards, Norbert
>


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