As we usually do, remove old unix socket before bind.
Note that systemd-udevd-control.socket has `RemoveOnStop=yes`.
So, it is not necessary to be removed when the service exits.
Replaces #20584 and #20588.
This is a small cosmetic change.
Before:
Offered DHCP leases: 192.168.0.183 (to 0:9:a7:36:bc:89)
After:
Offered DHCP leases: 192.168.0.183 (to 00:09:a7:36:bc:89)
The 'security' verb of systemd-analyze needs to be able to parse JSON files to be able to read in
the user-defined requirements and use them to determine the overall exposure level of the specified unit
file(s). The JSON files are expected to have a specific format where the keys in the file are the
unit ids consisting of only alphanumeric characters and underscores and the values are JSON objects
again consisting of key value pairs. The keys in these objects may include one or more of the following
properties: description_na, description_good, description_bad, weight, and range. The first three of these
are expected to be strings and the latter two are expected to be unsigned integer values. If one or more
of these properties is missing from the JSON object, then the default values of the properties as specified
in the hard coded set of security directives is used. The other properties that assess() needs to determine
overall exposure levels for a unit file for example, the assess function and parameter type among others,
are not to be included in the JSON files defined by the user because the values assigned to these fields
are expected to be consistent across unit files for each id.
A new option --security-policy= is added to work with the 'security' verb in order to enable
users to create and pass in a JSON file consisting of user defined requirements
against which to compare the specified unit file(s). These requirements then serve
as the measure of security threats for the file instead of the initial hard coded set of
requirements that the 'security' verb of systemd-analyze relied on.
Example Run:
A snapshot of the user defined testfile.json file is shown below instead of the complete file
for readability purposes.
{
"PrivateDevices":
{"description_good": "Service has no access to hardware devices",
"description_bad": "Service potentially has access to hardware devices",
"weight": 1000,
"range": 1
},
"PrivateMounts":
{"description_good": "Service cannot install system mounts",
"description_bad": "Service may install system mounts",
"weight": 1000,
"range": 1
},
"PrivateNetwork":
{"description_good": "Service has no access to the host's network",
"description_bad": "Service has access to the host's network",
"weight": 2500,
"range": 1
},
"PrivateTmp":
{"description_good": "Service has no access to other software's temporary files",
"description_bad": "Service has access to other software's temporary files",
"weight": 1000,
"range": 1
},
"PrivateUsers":
{"description_good": "Service does not have access to other users",
"description_bad": "Service has access to other users",
"weight": 1000,
"range": 1
}
}
1. I created the jsontest.service file in order to test the --security-policy= option as follows:
maanya-goenka@debian:~/systemd (custom-security)$ cat<<EOF>jsontest.service
> [Service]
> ExecStart = echo hello
> PrivateNetwork = yes
> PrivateDevices = yes
> PrivateMounts = yes
> EOF
The security analysis table outputted below has been truncated to include only the first few lines for readability.
maanya-goenka@debian:~/systemd (custom-security)$ sudo build/systemd-analyze security --root= --offline=true
--security-policy=src/analyze/testfile.json jsontest.service
/usr/lib/systemd/system/plymouth-start.service:15: Unit configured to use KillMode=none. This is unsafe, as it disables systemd's
process lifecycle management for the service. Please update your service to use a safer KillMode=, such as 'mixed' or 'control-group'.
Support for KillMode=none is deprecated and will eventually be removed.
/usr/lib/systemd/system/gdm.service:30: Standard output type syslog is obsolete, automatically updating to journal. Please update your
unit file, and consider removing the setting altogether.
/usr/lib/systemd/system/dbus.socket:5: ListenStream= references a path below legacy directory /var/run/, updating
/var/run/dbus/system_bus_socket → /run/dbus/system_bus_socket; please update the unit file accordingly.
NAME DESCRIPTION
✓ PrivateNetwork Service has no access to the host's network
✗ UserOrDynamicUser Service runs as root user
✗ CapabilityBoundingSet_CAP_SET_UID_GID_PCAP Service may change UID/GID identities/capabilities
✓ PrivateMounts Service cannot install system mounts
✓ PrivateDevices Service has no access to hardware devices
→ Overall exposure level for jsontest.service: 8.3 EXPOSED 🙁
maanya-goenka@debian:~/systemd (custom-security)$ echo $? 0
2. In order to ensure that the JSON data was actually being correctly parsed, I made some changes to the JSON
file, specifically to the id "PrivateNetwork" as follows:
Before:
--------
"PrivateNetwork":
{"description_good": "Service has no access to the host's network",
"description_bad": "Service has access to the host's network",
"weight": 2500,
"range": 1
}
After:
--------
"PrivateNetwork":
{"description_good": "Service runs without access to host network",
"description_bad": "Service has access to the host's network",
"weight": 6000,
"range": 1
}
As expected, the new description for the description_good field of the Private Network id was updated in
the analysis table outputted below and the overall exposure level of the unit file decreased because
the weight assigned to 'Private Network' (which is set to yes) increased from 2500 to 6000.
maanya-goenka@debian:~/systemd (custom-security)$ sudo build/systemd-analyze security --root= --offline=true
--security-policy=src/analyze/testfile.json jsontest.service
/usr/lib/systemd/system/plymouth-start.service:15: Unit configured to use KillMode=none. This is unsafe, as it disables systemd's
process lifecycle management for the service. Please update your service to use a safer KillMode=, such as 'mixed' or 'control-group'.
Support for KillMode=none is deprecated and will eventually be removed.
/usr/lib/systemd/system/gdm.service:30: Standard output type syslog is obsolete, automatically updating to journal. Please update your
unit file, and consider removing the setting altogether.
/usr/lib/systemd/system/dbus.socket:5: ListenStream= references a path below legacy directory /var/run/, updating
/var/run/dbus/system_bus_socket → /run/dbus/system_bus_socket; please update the unit file accordingly.
NAME DESCRIPTION
✓ PrivateNetwork Service runs without access to the host's network
✗ UserOrDynamicUser Service runs as root user
✗ CapabilityBoundingSet_CAP_SET_UID_GID_PCAP Service may change UID/GID identities/capabilities
✓ PrivateMounts Service cannot install system mounts
✓ PrivateDevices Service has no access to hardware devices
→ Overall exposure level for jsontest.service: 7.8 EXPOSED 🙁
maanya-goenka@debian:~/systemd (custom-security)$ echo $? 0
3. When paired with security's --threshold= option, systemd-analyze exits with a non-zero error status indicating
that the overall exposure level for the unit file (=78) is greater than the set threshold (=70). The same
jsontest.service file is used for the demo run below:
maanya-goenka@debian:~/systemd (custom-security)$ sudo build/systemd-analyze security --root= --offline=true
--security-policy=src/analyze/testfile.json --threshold=70 jsontest.service
/usr/lib/systemd/system/plymouth-start.service:15: Unit configured to use KillMode=none. This is unsafe, as it disables systemd's
process lifecycle management for the service. Please update your service to use a safer KillMode=, such as 'mixed' or 'control-group'.
Support for KillMode=none is deprecated and will eventually be removed.
/usr/lib/systemd/system/gdm.service:30: Standard output type syslog is obsolete, automatically updating to journal. Please update your
unit file, and consider removing the setting altogether.
/usr/lib/systemd/system/dbus.socket:5: ListenStream= references a path below legacy directory /var/run/, updating
/var/run/dbus/system_bus_socket → /run/dbus/system_bus_socket; please update the unit file accordingly.
NAME DESCRIPTION
✓ PrivateNetwork Service runs without access to host network
✗ UserOrDynamicUser Service runs as root user
✗ CapabilityBoundingSet_CAP_SET_UID_GID_PCAP Service may change UID/GID identities/capabilities
✓ PrivateMounts Service cannot install system mounts
✓ PrivateDevices Service has no access to hardware devices
→ Overall exposure level for jsontest.service: 7.8 EXPOSED 🙁
maanya-goenka@debian:~/systemd (custom-security)$ echo $? 1
new option
See libxtrans commit 0794b1b712a90b40e2b019c9edc6f96874493c52. The code
to generate this socket was removed 5 years ago and even before it was
conditional on #define TEST_t. There is no reference to that #define in
either the X server nor libX11's git history, or in any of the current
libX*.
Let's assume this is well and truly obsolete.
In 2020 mount.cifs started to require a bunch for caps to work. let's
add them to the capability bounding set.
Also, SMB support obviously needs network access, hence open that up.
Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1962920
Previously volatile-root was only checked if "/" wasn't backed by a
block device, but the block device isn't necessarily original root block
device (ex: if the rootfs is copied to a ext4 fs backed by zram in the
initramfs), so we always want volatile-root checked.
So shuffle the code around so volatile-root is checked first and
fallback to the automatic logic.
Fix#20557
The `sd_path_lookup(3)` man page states that the returned string shall be
`free(3)`'d but then doesn't do so in the example code.
Also add basic error handling as well.
When we are in --user mode there's no point in doing PolicyKit/ask-pw
because both of these systems are only used by system-level services.
Let's disable the two agents for that automaticlly hence.
Prompted by: #20576
Yu Watanabe
Lennart Poettering
Daan De Meyer
Jan Kuparinen
Luca Boccassi
Alvin Šipraga
Maanya Goenka
Peter Hutterer
Kristian Klausen
Thomas Mühlbacher
jlempen
José Expósito