diff options
| -rw-r--r-- | NEWS | 15 | ||||
| -rw-r--r-- | man/systemd.exec.xml | 16 | ||||
| -rw-r--r-- | src/core/unit.c | 10 | ||||
| -rw-r--r-- | units/systemd-journal-gatewayd.service.in | 1 | ||||
| -rw-r--r-- | units/systemd-journal-upload.service.in | 1 |
5 files changed, 33 insertions, 10 deletions
@@ -201,6 +201,21 @@ CHANGES WITH 242 in spe: done anymore, and instead calling `systemctl preset-all` is recommended after the first installation of systemd. + * A new boolean sandboxing option RestrictSUIDSGID= has been added that + is built on seccomp. When turned on creation of SUID/SGID files is + prohibited. + + * The NoNewPrivileges= and the new RestrictSUIDSGID= options are now + implied if DynamicUser= is turned on for a service. This hardens + these services, so that they neither can benefit from nor create + SUID/SGID executables. This is a minor compatibility breakage, given + that when DynamicUser= was first introduced SUID/SGID behaviour was + unaffected. However, the security benefit of these two options is + substantial, and the setting is still relatively new, hence we opted + to make it mandatory for services with dynamic users. + + … + CHANGES WITH 241: * The default locale can now be configured at compile time. Otherwise, diff --git a/man/systemd.exec.xml b/man/systemd.exec.xml index 46f2d856e0..688147ea32 100644 --- a/man/systemd.exec.xml +++ b/man/systemd.exec.xml @@ -252,7 +252,9 @@ of the service, and hence the lifetime of the dynamic user/group. Since <filename>/tmp</filename> and <filename>/var/tmp</filename> are usually the only world-writable directories on a system this ensures that a unit making use of dynamic user/group allocation cannot leave files around after unit - termination. Moreover <varname>ProtectSystem=strict</varname> and + termination. Furthermore <varname>NoNewPrivileges=</varname> and <varname>RestrictSUIDSGID=</varname> + are implicitly enabled to ensure that processes invoked cannot take benefit or create SUID/SGID files + or directories. Moreover <varname>ProtectSystem=strict</varname> and <varname>ProtectHome=read-only</varname> are implied, thus prohibiting the service to write to arbitrary file system locations. In order to allow the service to write to certain directories, they have to be whitelisted using <varname>ReadWritePaths=</varname>, but care must be taken so that @@ -388,11 +390,12 @@ CapabilityBoundingSet=~CAP_B CAP_C</programlisting> <varname>RestrictAddressFamilies=</varname>, <varname>RestrictNamespaces=</varname>, <varname>PrivateDevices=</varname>, <varname>ProtectKernelTunables=</varname>, <varname>ProtectKernelModules=</varname>, <varname>MemoryDenyWriteExecute=</varname>, - <varname>RestrictRealtime=</varname>, <varname>RestrictSUIDSGID=</varname> or - <varname>LockPersonality=</varname> are specified. Note that even if this setting is overridden by - them, <command>systemctl show</command> shows the original value of this setting. Also see <ulink + <varname>RestrictRealtime=</varname>, <varname>RestrictSUIDSGID=</varname>, + <varname>DynamicUser=</varname> or <varname>LockPersonality=</varname> are specified. Note that even + if this setting is overridden by them, <command>systemctl show</command> shows the original value of + this setting. Also see <ulink url="https://www.kernel.org/doc/html/latest/userspace-api/no_new_privs.html">No New Privileges - Flag</ulink>. </para></listitem> + Flag</ulink>.</para></listitem> </varlistentry> <varlistentry> @@ -1406,7 +1409,8 @@ RestrictNamespaces=~cgroup net</programlisting> identity of other users, it is recommended to restrict creation of SUID/SGID files to the few programs that actually require them. Note that this restricts marking of any type of file system object with these bits, including both regular files and directories (where the SGID is a different - meaning than for files, see documentation). Defaults to off.</para></listitem> + meaning than for files, see documentation). This option is implied if <varname>DynamicUser=</varname> + is enabled. Defaults to off.</para></listitem> </varlistentry> <varlistentry> diff --git a/src/core/unit.c b/src/core/unit.c index 35c268cd3b..2cde494a7e 100644 --- a/src/core/unit.c +++ b/src/core/unit.c @@ -4088,14 +4088,20 @@ int unit_patch_contexts(Unit *u) { return -ENOMEM; } - /* If the dynamic user option is on, let's make sure that the unit can't leave its UID/GID - * around in the file system or on IPC objects. Hence enforce a strict sandbox. */ + /* If the dynamic user option is on, let's make sure that the unit can't leave its + * UID/GID around in the file system or on IPC objects. Hence enforce a strict + * sandbox. */ ec->private_tmp = true; ec->remove_ipc = true; ec->protect_system = PROTECT_SYSTEM_STRICT; if (ec->protect_home == PROTECT_HOME_NO) ec->protect_home = PROTECT_HOME_READ_ONLY; + + /* Make sure this service can neither benefit from SUID/SGID binaries nor create + * them. */ + ec->no_new_privileges = true; + ec->restrict_suid_sgid = true; } } diff --git a/units/systemd-journal-gatewayd.service.in b/units/systemd-journal-gatewayd.service.in index 0f16ae4ccb..50f774512b 100644 --- a/units/systemd-journal-gatewayd.service.in +++ b/units/systemd-journal-gatewayd.service.in @@ -17,7 +17,6 @@ DynamicUser=yes ExecStart=@rootlibexecdir@/systemd-journal-gatewayd LockPersonality=yes MemoryDenyWriteExecute=yes -NoNewPrivileges=yes PrivateDevices=yes PrivateNetwork=yes ProtectControlGroups=yes diff --git a/units/systemd-journal-upload.service.in b/units/systemd-journal-upload.service.in index 10e4d657d3..e3800473ec 100644 --- a/units/systemd-journal-upload.service.in +++ b/units/systemd-journal-upload.service.in @@ -18,7 +18,6 @@ DynamicUser=yes ExecStart=@rootlibexecdir@/systemd-journal-upload --save-state LockPersonality=yes MemoryDenyWriteExecute=yes -NoNewPrivileges=yes PrivateDevices=yes ProtectControlGroups=yes ProtectHome=yes |