Tighten up start-stop-daemon invocations

Pass "--exec /usr/sbin/sshd" to start-stop-daemon on stop as well as
start and pass "--chuid 0:0" on start, to avoid problems with non-root
groups leaking into the ownership of /run/sshd.pid.

Closes: #922365

2 files changed, 9 insertions, 6 deletions

diff --git a/debian/changelog b/debian/changelog
index 04b0914ac..c7b93aaf5 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -4,6 +4,9 @@ openssh (1:7.9p1-7) UNRELEASED; urgency=medium
     libpam-systemd (closes: #923199).  (I've retained libpam-systemd as an
     alternative for a while to avoid backporting accidents, although it can
     be removed later.)
+  * Pass "--exec /usr/sbin/sshd" to start-stop-daemon on stop as well as
+    start and pass "--chuid 0:0" on start, to avoid problems with non-root
+    groups leaking into the ownership of /run/sshd.pid (closes: #922365).
 
  -- Colin Watson <cjwatson@debian.org>  Mon, 25 Feb 2019 16:26:28 +0000
 
diff --git a/debian/openssh-server.ssh.init b/debian/openssh-server.ssh.init
index f25000883..620af70e0 100644..100755
--- a/debian/openssh-server.ssh.init
+++ b/debian/openssh-server.ssh.init
@@ -80,7 +80,7 @@ case "$1" in
         check_for_no_start
         check_dev_null
         log_daemon_msg "Starting OpenBSD Secure Shell server" "sshd" || true
-        if start-stop-daemon --start --quiet --oknodo --pidfile /run/sshd.pid --exec /usr/sbin/sshd -- $SSHD_OPTS; then
+        if start-stop-daemon --start --quiet --oknodo --chuid 0:0 --pidfile /run/sshd.pid --exec /usr/sbin/sshd -- $SSHD_OPTS; then
             log_end_msg 0 || true
         else
             log_end_msg 1 || true
@@ -88,7 +88,7 @@ case "$1" in
         ;;
   stop)
         log_daemon_msg "Stopping OpenBSD Secure Shell server" "sshd" || true
-        if start-stop-daemon --stop --quiet --oknodo --pidfile /run/sshd.pid; then
+        if start-stop-daemon --stop --quiet --oknodo --pidfile /run/sshd.pid --exec /usr/sbin/sshd; then
             log_end_msg 0 || true
         else
             log_end_msg 1 || true
@@ -110,10 +110,10 @@ case "$1" in
         check_privsep_dir
         check_config
         log_daemon_msg "Restarting OpenBSD Secure Shell server" "sshd" || true
-        start-stop-daemon --stop --quiet --oknodo --retry 30 --pidfile /run/sshd.pid
+        start-stop-daemon --stop --quiet --oknodo --retry 30 --pidfile /run/sshd.pid --exec /usr/sbin/sshd
         check_for_no_start log_end_msg
         check_dev_null log_end_msg
-        if start-stop-daemon --start --quiet --oknodo --pidfile /run/sshd.pid --exec /usr/sbin/sshd -- $SSHD_OPTS; then
+        if start-stop-daemon --start --quiet --oknodo --chuid 0:0 --pidfile /run/sshd.pid --exec /usr/sbin/sshd -- $SSHD_OPTS; then
             log_end_msg 0 || true
         else
             log_end_msg 1 || true
@@ -125,13 +125,13 @@ case "$1" in
         check_config
         log_daemon_msg "Restarting OpenBSD Secure Shell server" "sshd" || true
         RET=0
-        start-stop-daemon --stop --quiet --retry 30 --pidfile /run/sshd.pid || RET="$?"
+        start-stop-daemon --stop --quiet --retry 30 --pidfile /run/sshd.pid --exec /usr/sbin/sshd || RET="$?"
         case $RET in
             0)
                 # old daemon stopped
                 check_for_no_start log_end_msg
                 check_dev_null log_end_msg
-                if start-stop-daemon --start --quiet --oknodo --pidfile /run/sshd.pid --exec /usr/sbin/sshd -- $SSHD_OPTS; then
+                if start-stop-daemon --start --quiet --oknodo --chuid 0:0 --pidfile /run/sshd.pid --exec /usr/sbin/sshd -- $SSHD_OPTS; then
                     log_end_msg 0 || true
                 else
                     log_end_msg 1 || true