units: add a basic SystemCallFilter (#3471)

Add a line
SystemCallFilter=~@clock @module @mount @obsolete @raw-io ptrace
for daemons shipped by systemd. As an exception, systemd-timesyncd
needs @clock system calls and systemd-localed is not privileged.
ptrace(2) is blocked to prevent seccomp escapes.

10 files changed, 10 insertions, 0 deletions

diff --git a/units/systemd-hostnamed.service.in b/units/systemd-hostnamed.service.in
index fc43b2c4a6..d8f18bed53 100644
--- a/units/systemd-hostnamed.service.in
+++ b/units/systemd-hostnamed.service.in
@@ -21,3 +21,4 @@ PrivateNetwork=yes
 ProtectSystem=yes
 ProtectHome=yes
 MemoryDenyWriteExecute=yes
+SystemCallFilter=~@clock @module @mount @obsolete @raw-io ptrace
diff --git a/units/systemd-importd.service.in b/units/systemd-importd.service.in
index 2f8138e88e..a3d1a1519b 100644
--- a/units/systemd-importd.service.in
+++ b/units/systemd-importd.service.in
@@ -18,3 +18,4 @@ NoNewPrivileges=yes
 WatchdogSec=3min
 KillMode=mixed
 MemoryDenyWriteExecute=yes
+SystemCallFilter=~@clock @module @mount @obsolete @raw-io ptrace
diff --git a/units/systemd-journald.service.in b/units/systemd-journald.service.in
index 06abe04861..58808d4f8c 100644
--- a/units/systemd-journald.service.in
+++ b/units/systemd-journald.service.in
@@ -25,6 +25,7 @@ CapabilityBoundingSet=CAP_SYS_ADMIN CAP_DAC_OVERRIDE CAP_SYS_PTRACE CAP_SYSLOG C
 WatchdogSec=3min
 FileDescriptorStoreMax=1024
 MemoryDenyWriteExecute=yes
+SystemCallFilter=~@clock @module @mount @obsolete @raw-io ptrace
 
 # Increase the default a bit in order to allow many simultaneous
 # services being run since we keep one fd open per service. Also, when
diff --git a/units/systemd-localed.service.in b/units/systemd-localed.service.in
index 743221472c..5efa677548 100644
--- a/units/systemd-localed.service.in
+++ b/units/systemd-localed.service.in
@@ -21,3 +21,4 @@ PrivateNetwork=yes
 ProtectSystem=yes
 ProtectHome=yes
 MemoryDenyWriteExecute=yes
+SystemCallFilter=~@clock @module @mount @obsolete @privileged @raw-io ptrace
diff --git a/units/systemd-logind.service.in b/units/systemd-logind.service.in
index 67e2c34482..a9598760e2 100644
--- a/units/systemd-logind.service.in
+++ b/units/systemd-logind.service.in
@@ -26,6 +26,7 @@ BusName=org.freedesktop.login1
 CapabilityBoundingSet=CAP_SYS_ADMIN CAP_MAC_ADMIN CAP_AUDIT_CONTROL CAP_CHOWN CAP_KILL CAP_DAC_READ_SEARCH CAP_DAC_OVERRIDE CAP_FOWNER CAP_SYS_TTY_CONFIG
 WatchdogSec=3min
 MemoryDenyWriteExecute=yes
+SystemCallFilter=~@clock @module @mount @obsolete @raw-io ptrace
 
 # 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 1517068ecd..82dca05338 100644
--- a/units/systemd-machined.service.in
+++ b/units/systemd-machined.service.in
@@ -18,6 +18,7 @@ BusName=org.freedesktop.machine1
 CapabilityBoundingSet=CAP_KILL CAP_SYS_PTRACE CAP_SYS_ADMIN CAP_SETGID CAP_SYS_CHROOT CAP_DAC_READ_SEARCH CAP_DAC_OVERRIDE CAP_CHOWN CAP_FOWNER CAP_FSETID CAP_MKNOD
 WatchdogSec=3min
 MemoryDenyWriteExecute=yes
+SystemCallFilter=~@clock @module @mount @obsolete @raw-io ptrace
 
 # Note that machined cannot be placed in a mount namespace, since it
 # needs access to the host's mount namespace in order to implement the
diff --git a/units/systemd-networkd.service.m4.in b/units/systemd-networkd.service.m4.in
index 3c9970fa48..3feb2b84f5 100644
--- a/units/systemd-networkd.service.m4.in
+++ b/units/systemd-networkd.service.m4.in
@@ -32,6 +32,7 @@ ProtectSystem=full
 ProtectHome=yes
 WatchdogSec=3min
 MemoryDenyWriteExecute=yes
+SystemCallFilter=~@clock @module @mount @obsolete @raw-io ptrace
 
 [Install]
 WantedBy=multi-user.target
diff --git a/units/systemd-resolved.service.m4.in b/units/systemd-resolved.service.m4.in
index 07c7658bcc..4a94f747e2 100644
--- a/units/systemd-resolved.service.m4.in
+++ b/units/systemd-resolved.service.m4.in
@@ -28,6 +28,7 @@ ProtectSystem=full
 ProtectHome=yes
 WatchdogSec=3min
 MemoryDenyWriteExecute=yes
+SystemCallFilter=~@clock @module @mount @obsolete @raw-io ptrace
 
 [Install]
 WantedBy=multi-user.target
diff --git a/units/systemd-timedated.service.in b/units/systemd-timedated.service.in
index 3636091472..1bdbe65aad 100644
--- a/units/systemd-timedated.service.in
+++ b/units/systemd-timedated.service.in
@@ -19,3 +19,4 @@ PrivateTmp=yes
 ProtectSystem=yes
 ProtectHome=yes
 MemoryDenyWriteExecute=yes
+SystemCallFilter=~@module @mount @obsolete @raw-io ptrace
diff --git a/units/systemd-timesyncd.service.in b/units/systemd-timesyncd.service.in
index caf1dc132f..8c86021f5e 100644
--- a/units/systemd-timesyncd.service.in
+++ b/units/systemd-timesyncd.service.in
@@ -29,6 +29,7 @@ ProtectSystem=full
 ProtectHome=yes
 WatchdogSec=3min
 MemoryDenyWriteExecute=yes
+SystemCallFilter=~@module @mount @obsolete @raw-io ptrace
 
 [Install]
 WantedBy=sysinit.target