start-scripts: switch to $PGUSER before opening $PGLOG.

By default, $PGUSER has permission to unlink $PGLOG.  If $PGUSER
replaces $PGLOG with a symbolic link, the server will corrupt the
link-targeted file by appending log messages.  Since these scripts open
$PGLOG as root, the attack works regardless of target file ownership.

"make install" does not install these scripts anywhere.  Users having
manually installed them in the past should repeat that process to
acquire this fix.  Most script users have $PGLOG writable to root only,
located in $PGDATA.  Just before updating one of these scripts, such
users should rename $PGLOG to $PGLOG.old.  The script will then recreate
$PGLOG with proper ownership.

Reviewed by Peter Eisentraut.  Reported by Antoine Scemama.

Security: CVE-2017-12172

3 files changed, 8 insertions, 8 deletions

diff --git a/contrib/start-scripts/freebsd b/contrib/start-scripts/freebsd
index 758574b427f..e37421253d9 100644
--- a/contrib/start-scripts/freebsd
+++ b/contrib/start-scripts/freebsd
@@ -44,7 +44,7 @@ test -x $DAEMON ||
 
 case $1 in
     start)
-	su -l $PGUSER -c "$DAEMON -D '$PGDATA' &" >>$PGLOG 2>&1
+	su -l $PGUSER -c "$DAEMON -D '$PGDATA' >>$PGLOG 2>&1 &"
 	echo -n ' postgresql'
 	;;
     stop)
@@ -52,7 +52,7 @@ case $1 in
 	;;
     restart)
 	su -l $PGUSER -c "$PGCTL stop -D '$PGDATA' -s -m fast -w"
-	su -l $PGUSER -c "$DAEMON -D '$PGDATA' &" >>$PGLOG 2>&1
+	su -l $PGUSER -c "$DAEMON -D '$PGDATA' >>$PGLOG 2>&1 &"
 	;;
     status)
 	su -l $PGUSER -c "$PGCTL status -D '$PGDATA'"
diff --git a/contrib/start-scripts/linux b/contrib/start-scripts/linux
index b950cf512c3..023a4ca1e64 100644
--- a/contrib/start-scripts/linux
+++ b/contrib/start-scripts/linux
@@ -84,7 +84,7 @@ case $1 in
 	echo -n "Starting PostgreSQL: "
 	test x"$OOM_SCORE_ADJ" != x && echo "$OOM_SCORE_ADJ" > /proc/self/oom_score_adj
 	test x"$OOM_ADJ" != x && echo "$OOM_ADJ" > /proc/self/oom_adj
-	su - $PGUSER -c "$DAEMON -D '$PGDATA' &" >>$PGLOG 2>&1
+	su - $PGUSER -c "$DAEMON -D '$PGDATA' >>$PGLOG 2>&1 &"
 	echo "ok"
 	;;
   stop)
@@ -97,7 +97,7 @@ case $1 in
 	su - $PGUSER -c "$PGCTL stop -D '$PGDATA' -s -m fast -w"
 	test x"$OOM_SCORE_ADJ" != x && echo "$OOM_SCORE_ADJ" > /proc/self/oom_score_adj
 	test x"$OOM_ADJ" != x && echo "$OOM_ADJ" > /proc/self/oom_adj
-	su - $PGUSER -c "$DAEMON -D '$PGDATA' &" >>$PGLOG 2>&1
+	su - $PGUSER -c "$DAEMON -D '$PGDATA' >>$PGLOG 2>&1 &"
 	echo "ok"
 	;;
   reload)
diff --git a/contrib/start-scripts/osx/PostgreSQL b/contrib/start-scripts/osx/PostgreSQL
index 2ef5d220c40..11cc57c4005 100755
--- a/contrib/start-scripts/osx/PostgreSQL
+++ b/contrib/start-scripts/osx/PostgreSQL
@@ -81,9 +81,9 @@ StartService () {
     if [ "${POSTGRESQL:=-NO-}" = "-YES-" ]; then
         ConsoleMessage "Starting PostgreSQL database server"
         if [ "${ROTATELOGS}" = "1" ]; then
-            sudo -u $PGUSER sh -c "${DAEMON} -D '${PGDATA}' &" 2>&1 | ${LOGUTIL} "${PGLOG}" ${ROTATESEC} &
+            sudo -u $PGUSER sh -c "${DAEMON} -D '${PGDATA}' 2>&1 | ${LOGUTIL} \"${PGLOG}\" ${ROTATESEC} &"
         else
-            sudo -u $PGUSER sh -c "${DAEMON} -D '${PGDATA}' &" >>"$PGLOG" 2>&1
+            sudo -u $PGUSER sh -c "${DAEMON} -D '${PGDATA}' >>\"$PGLOG\" 2>&1 &"
         fi
     fi
 }
@@ -100,9 +100,9 @@ RestartService () {
 	sudo -u $PGUSER sh -c "$PGCTL stop -D '${PGDATA}' -s -m fast"
 	# should match StartService:
         if [ "${ROTATELOGS}" = "1" ]; then
-            sudo -u $PGUSER sh -c "${DAEMON} -D '${PGDATA}' &" 2>&1 | ${LOGUTIL} "${PGLOG}" ${ROTATESEC} &
+            sudo -u $PGUSER sh -c "${DAEMON} -D '${PGDATA}' 2>&1 | ${LOGUTIL} \"${PGLOG}\" ${ROTATESEC} &"
         else
-            sudo -u $PGUSER sh -c "${DAEMON} -D '${PGDATA}' &" >>"$PGLOG" 2>&1
+            sudo -u $PGUSER sh -c "${DAEMON} -D '${PGDATA}' >>\"$PGLOG\" 2>&1 &"
         fi
     else
         StopService