Add a basic noble migration check script

Perform a number of checks to ensure the system is ready for the noble
migration. The results are written to a JSON file in /etc/ that other
things like the JI and the upgrade script itself can read from.

The script is run hourly on a systemd timer but can also be run
interactively for administrators who want slightly more details.

Refs #7322.

molecule/testinfra/common/test_release_upgrades.py

@@ -1,3 +1,6 @@
+import time
+
+import pytest
 import testutils
 
 test_vars = testutils.securedrop_test_vars
@@ -27,3 +30,20 @@ def test_release_manager_upgrade_channel(host):
     _, channel = raw_output.split("=")
 
     assert channel == "never"
+
+
+def test_migration_check(host):
+    """Verify our migration check script works"""
+    if host.system_info.codename != "focal":
+        pytest.skip("only applicable/testable on focal")
+
+    with host.sudo():
+        # remove state file so we can see if it works
+        if host.file("/etc/securedrop-noble-migration.json").exists:
+            host.run("rm /etc/securedrop-noble-migration.json")
+        cmd = host.run("systemctl start securedrop-noble-migration-check")
+        assert cmd.rc == 0
+        while host.service("securedrop-noble-migration-check").is_running:
+            time.sleep(1)
+
+        assert host.file("/etc/securedrop-noble-migration.json").exists

securedrop/debian/config/lib/systemd/system/securedrop-noble-migration-check.service

@@ -0,0 +1,7 @@
+[Unit]
+Description=Check noble migration readiness
+
+[Service]
+Type=oneshot
+ExecStart=/usr/bin/securedrop-noble-migration-check.py
+User=root

securedrop/debian/config/lib/systemd/system/securedrop-noble-migration-check.timer

@@ -0,0 +1,10 @@
+[Unit]
+Description=Check noble migration readiness
+
+[Timer]
+OnCalendar=hourly
+Persistent=true
+RandomizedDelaySec=5m
+
+[Install]
+WantedBy=timers.target

securedrop/debian/config/usr/bin/securedrop-noble-migration-check.py

@@ -0,0 +1,142 @@
+#!/usr/bin/python3
+"""
+Check migration of a SecureDrop server from focal to noble
+
+This script is run as root on both the app and mon servers.
+"""
+
+import grp
+import json
+import os
+import shutil
+import subprocess
+import sys
+import traceback
+from pathlib import Path
+from urllib.parse import urlparse
+
+
+def os_codename() -> str:
+    with open("/etc/os-release") as f:
+        os_release = f.readlines()
+        for line in os_release:
+            if line.startswith("VERSION_CODENAME="):
+                return line.split("=")[1].strip().strip('"')
+    raise ValueError("Could not determine Ubuntu codename")
+
+
+def check_ssh_group() -> bool:
+    """Check the UNIX "ssh" group is empty"""
+    try:
+        group = grp.getgrnam("ssh")
+    except KeyError:
+        print("ssh: group does not exist")
+        return True
+
+    if len(group.gr_mem) > 0:
+        print(f"ssh: group is not empty: {group.gr_mem}")
+        return False
+
+    print("ssh: group is empty")
+    return True
+
+
+def check_ufw_removed() -> bool:
+    """Check that ufw is removed"""
+    if Path("/usr/sbin/ufw").exists():
+        print("ufw: ufw is still installed")
+        return False
+    else:
+        print("ufw: ufw was removed")
+        return True
+
+
+def check_free_space() -> bool:
+    """Check the root partition has more than 10G free"""
+    root = shutil.disk_usage("/")
+    if root.free < (10 * 1024 * 1024 * 1024):
+        print("free space: not enough free space")
+        return False
+    else:
+        print("free space: enough free space")
+        return True
+
+
+def check_apt() -> bool:
+    """Verify only expected sources are configured"""
+    try:
+        output = subprocess.check_output(["apt-get", "indextargets"], text=True)
+    except subprocess.CalledProcessError:
+        print("apt: error invoking apt-get indextargets")
+        return False
+
+    for line in output.splitlines():
+        if line.startswith("URI:"):
+            parsed = urlparse(line.split(":", 1)[1].strip())
+            if parsed.hostname not in [
+                "archive.ubuntu.com",
+                "security.ubuntu.com",
+                "apt.freedom.press",
+                "apt-test.freedom.press",
+            ]:
+                print(f"apt: unexpected source: {parsed.hostname}")
+                return False
+
+    print("apt: all sources are expected")
+    return True
+
+
+def check_systemd() -> bool:
+    """ "No systemd units are failed"""
+    try:
+        subprocess.check_output(["systemctl", "is-failed"])
+        print("systemd: some systemd units are failed")
+        return False
+    except subprocess.CalledProcessError:
+        print("systemd: all systemd units are running")
+        return True
+
+
+def main() -> None:
+    if os.geteuid() != 0:
+        print("You need to run this as root")
+        sys.exit(1)
+
+    state_path = Path("/etc/securedrop-noble-migration.json")
+    codename = os_codename()
+
+    if codename != "focal":
+        print(f"Unsupported Ubuntu version: {codename}")
+        # nothing to do, write an empty JSON blob
+        state_path.write_text(json.dumps({}))
+        return
+
+    state = {}
+    state["ssh"] = check_ssh_group()
+    state["ufw"] = check_ufw_removed()
+    state["free_space"] = check_free_space()
+    state["apt"] = check_apt()
+    state["systemd"] = check_systemd()
+
+    state_path.write_text(json.dumps(state))
+
+    if all(state.values()):
+        print("All ready for migration!")
+        sys.exit(0)
+    else:
+        print("""\
+
+Some errors were found that will block migration.
+
+If you are unsure what to do, please contact the SecureDrop
+support team: <https://docs.securedrop.org/en/stable/getting_support.html>.
+""")
+        sys.exit(1)
+
+
+if __name__ == "__main__":
+    try:
+        main()
+    except Exception as e:
+        traceback.print_exc()
+        Path("/etc/securedrop-noble-migration.json").write_text(json.dumps({"error": str(e)}))

securedrop/debian/rules

@@ -85,6 +85,7 @@ override_dh_systemd_enable:
 	dh_systemd_enable --no-enable securedrop-remove-pending-sources.service
 	dh_systemd_enable --no-enable securedrop-remove-packages.service
 	dh_systemd_enable --no-enable securedrop-cleanup-ossec.service
+	dh_systemd_enable --no-enable securedrop-noble-migration-check.service
 	dh_systemd_enable
 
 # This is basically the same as the enable stanza above, just whether the
@@ -95,4 +96,5 @@ override_dh_systemd_start:
 	dh_systemd_start --no-start securedrop-remove-pending-sources.service
 	dh_systemd_start --no-start securedrop-remove-packages.service
 	dh_systemd_start --no-start securedrop-cleanup-ossec.service
+	dh_systemd_start --no-start securedrop-noble-migration-check.service
 	dh_systemd_start