core: add new ReadOnlySystem= and ProtectedHome= settings for service units

ReadOnlySystem= uses fs namespaces to mount /usr and /boot read-only for
a service.

ProtectedHome= uses fs namespaces to mount /home and /run/user
inaccessible or read-only for a service.

This patch also enables these settings for all our long-running services.

Together they should be good building block for a minimal service
sandbox, removing the ability for services to modify the operating
system or access the user's private data.

11 files changed, 22 insertions, 0 deletions

diff --git a/units/systemd-hostnamed.service.in b/units/systemd-hostnamed.service.in
index 79e22c1d4..497b8d997 100644
--- a/units/systemd-hostnamed.service.in
+++ b/units/systemd-hostnamed.service.in
@@ -18,3 +18,5 @@ WatchdogSec=1min
 PrivateTmp=yes
 PrivateDevices=yes
 PrivateNetwork=yes
+ReadOnlySystem=yes
+ProtectedHome=yes
diff --git a/units/systemd-journal-gatewayd.service.in b/units/systemd-journal-gatewayd.service.in
index e8e571e69..3695240cb 100644
--- a/units/systemd-journal-gatewayd.service.in
+++ b/units/systemd-journal-gatewayd.service.in
@@ -17,6 +17,8 @@ SupplementaryGroups=systemd-journal
 PrivateTmp=yes
 PrivateDevices=yes
 PrivateNetwork=yes
+ReadOnlySystem=yes
+ProtectedHome=yes
 
 [Install]
 Also=systemd-journal-gatewayd.socket
diff --git a/units/systemd-journald.service.in b/units/systemd-journald.service.in
index de9387933..ba3f84720 100644
--- a/units/systemd-journald.service.in
+++ b/units/systemd-journald.service.in
@@ -20,6 +20,8 @@ RestartSec=0
 NotifyAccess=all
 StandardOutput=null
 CapabilityBoundingSet=CAP_SYS_ADMIN CAP_DAC_OVERRIDE CAP_SYS_PTRACE CAP_SYSLOG CAP_AUDIT_CONTROL CAP_CHOWN CAP_DAC_READ_SEARCH CAP_FOWNER CAP_SETUID CAP_SETGID
+ReadOnlySystem=yes
+ProtectedHome=yes
 WatchdogSec=1min
 
 # Increase the default a bit in order to allow many simultaneous
diff --git a/units/systemd-localed.service.in b/units/systemd-localed.service.in
index ae1c5e59d..e1792d654 100644
--- a/units/systemd-localed.service.in
+++ b/units/systemd-localed.service.in
@@ -18,3 +18,5 @@ WatchdogSec=1min
 PrivateTmp=yes
 PrivateDevices=yes
 PrivateNetwork=yes
+ReadOnlySystem=yes
+ProtectedHome=yes
diff --git a/units/systemd-logind.service.in b/units/systemd-logind.service.in
index c6cbd1c8d..68803fb38 100644
--- a/units/systemd-logind.service.in
+++ b/units/systemd-logind.service.in
@@ -25,6 +25,8 @@ RestartSec=0
 BusName=org.freedesktop.login1
 CapabilityBoundingSet=CAP_SYS_ADMIN CAP_AUDIT_CONTROL CAP_CHOWN CAP_KILL CAP_DAC_READ_SEARCH CAP_DAC_OVERRIDE CAP_FOWNER CAP_SYS_TTY_CONFIG
 WatchdogSec=1min
+ReadOnlySystem=yes
+ProtectedHome=yes
 
 # Increase the default a bit in order to allow many simultaneous
 # logins since we keep one fd open per session.
diff --git a/units/systemd-machined.service.in b/units/systemd-machined.service.in
index 1a27c6e42..07522e12a 100644
--- a/units/systemd-machined.service.in
+++ b/units/systemd-machined.service.in
@@ -20,3 +20,5 @@ WatchdogSec=1min
 PrivateTmp=yes
 PrivateDevices=yes
 PrivateNetwork=yes
+ReadOnlySystem=yes
+ProtectedHome=yes
diff --git a/units/systemd-networkd.service.in b/units/systemd-networkd.service.in
index 3538295df..a92899920 100644
--- a/units/systemd-networkd.service.in
+++ b/units/systemd-networkd.service.in
@@ -20,6 +20,8 @@ Restart=always
 RestartSec=0
 ExecStart=@rootlibexecdir@/systemd-networkd
 CapabilityBoundingSet=CAP_NET_ADMIN CAP_NET_BIND_SERVICE CAP_NET_BROADCAST CAP_NET_RAW CAP_SETUID CAP_SETGID CAP_SETPCAP CAP_CHOWN CAP_DAC_OVERRIDE CAP_FOWNER
+ReadOnlySystem=yes
+ProtectedHome=yes
 WatchdogSec=1min
 
 [Install]
diff --git a/units/systemd-resolved.service.in b/units/systemd-resolved.service.in
index 9d422ca7f..787fde2c4 100644
--- a/units/systemd-resolved.service.in
+++ b/units/systemd-resolved.service.in
@@ -16,6 +16,8 @@ Restart=always
 RestartSec=0
 ExecStart=@rootlibexecdir@/systemd-resolved
 CapabilityBoundingSet=CAP_SETUID CAP_SETGID CAP_SETPCAP CAP_CHOWN CAP_DAC_OVERRIDE CAP_FOWNER
+ReadOnlySystem=yes
+ProtectedHome=yes
 
 [Install]
 WantedBy=multi-user.target
diff --git a/units/systemd-timedated.service.in b/units/systemd-timedated.service.in
index 5c90290cd..9658149ee 100644
--- a/units/systemd-timedated.service.in
+++ b/units/systemd-timedated.service.in
@@ -16,3 +16,5 @@ BusName=org.freedesktop.timedate1
 CapabilityBoundingSet=CAP_SYS_TIME
 WatchdogSec=1min
 PrivateTmp=yes
+ReadOnlySystem=yes
+ProtectedHome=yes
diff --git a/units/systemd-timesyncd.service.in b/units/systemd-timesyncd.service.in
index cbde3ff67..030e4a042 100644
--- a/units/systemd-timesyncd.service.in
+++ b/units/systemd-timesyncd.service.in
@@ -23,6 +23,8 @@ ExecStart=@rootlibexecdir@/systemd-timesyncd
 CapabilityBoundingSet=CAP_SYS_TIME CAP_SETUID CAP_SETGID CAP_SETPCAP CAP_CHOWN CAP_DAC_OVERRIDE CAP_FOWNER
 PrivateTmp=yes
 PrivateDevices=yes
+ReadOnlySystem=yes
+ProtectedHome=yes
 WatchdogSec=1min
 
 [Install]
diff --git a/units/systemd-udevd.service.in b/units/systemd-udevd.service.in
index ddee01537..82275f052 100644
--- a/units/systemd-udevd.service.in
+++ b/units/systemd-udevd.service.in
@@ -22,3 +22,5 @@ Restart=always
 RestartSec=0
 ExecStart=@rootlibexecdir@/systemd-udevd
 MountFlags=slave
+ReadOnlySystem=yes
+ProtectedHome=yes