Check no new unexpected keys were installed during the upgrade

Petr Stodulka:

* some refactoring
* added added error logging
* replace the hard error stop by post upgrade report
  We do not want to interrupt the upgrade process after the
  DNF transaction execution

Signed-off-by: Jakub Jelen <[email protected]>

repos/system_upgrade/common/actors/gpgpubkeycheck/actor.py

@@ -0,0 +1,23 @@
+from leapp.actors import Actor
+from leapp.libraries.actor import gpgpubkeycheck
+from leapp.models import TrustedGpgKeys
+from leapp.reporting import Report
+from leapp.tags import ApplicationsPhaseTag, IPUWorkflowTag
+
+
+class GpgPubkeyCheck(Actor):
+    """
+    Checks no unexpected GPG keys were installed during the upgrade.
+
+    This should be mostly sanity check and this should not happen
+    unless something went very wrong, regardless the gpgcheck was
+    used (default) or not (with --no-gpgcheck option).
+    """
+
+    name = 'gpg_pubkey_check'
+    consumes = (TrustedGpgKeys,)
+    produces = (Report,)
+    tags = (IPUWorkflowTag, ApplicationsPhaseTag,)
+
+    def process(self):
+        gpgpubkeycheck.process()

repos/system_upgrade/common/actors/gpgpubkeycheck/libraries/gpgpubkeycheck.py

@@ -0,0 +1,124 @@
+from leapp import reporting
+from leapp.libraries.common.gpg import is_nogpgcheck_set
+from leapp.libraries.common.rpms import get_installed_rpms
+from leapp.libraries.stdlib import api
+from leapp.models import TrustedGpgKeys
+
+FMT_LIST_SEPARATOR = '\n    - '
+
+
+def _get_installed_fps_tuple():
+    """
+    Return list of tuples (fingerprint, packager).
+    """
+    installed_fps_tuple = []
+    rpms = get_installed_rpms()
+    for rpm in rpms:
+        rpm = rpm.strip()
+        if not rpm:
+            continue
+        try:
+            # NOTE: pgpsig is (none) for 'gpg-pubkey' entries
+            name, version, dummy_release, dummy_epoch, packager, dummy_arch, dummy_pgpsig = rpm.split('|')
+        except ValueError as e:
+            # NOTE: it's seatbelt, but if it happens, seeing loong list of errors
+            # will let us know earlier that we missed something really
+            api.current_logger().error('Cannot perform the check of installed GPG keys after the upgrade.')
+            api.current_logger().error('Cannot parse rpm output: {}'.format(e))
+            continue
+        if name != 'gpg-pubkey':
+            continue
+        installed_fps_tuple.append((version, packager))
+    return installed_fps_tuple
+
+
+def _report_cannot_check_keys(installed_fps):
+    # NOTE: in this case, it's expected there will be always some GPG keys present
+    summary = (
+        'Cannot perform the check of GPG keys installed in the RPM DB'
+        ' due to missing facts (TrustedGpgKeys) supposed to be generated'
+        ' in the start of the upgrade process on the original system.'
+        ' Unexpected unexpected installed GPG keys could be e.g. a mark of'
+        ' a malicious attempt to hijack the upgrade process.'
+        ' The list of all GPG keys in RPM DB:{sep}{key_list}'
+        .format(
+            sep=FMT_LIST_SEPARATOR,
+            key_list=FMT_LIST_SEPARATOR.join(installed_fps)
+        )
+    )
+    hint = (
+        'Verify the installed GPG keys are expected.'
+    )
+    groups = [
+        reporting.Groups.POST,
+        reporting.Groups.REPOSITORY,
+        reporting.Groups.SECURITY
+    ]
+    reporting.create_report([
+        reporting.Title('Cannot perform the check of installed GPG keys after the upgrade.'),
+        reporting.Summary(summary),
+        reporting.Severity(reporting.Severity.HIGH),
+        reporting.Groups(groups),
+        reporting.Remediation(hint=hint),
+    ])
+
+
+def _report_unexpected_keys(unexpected_fps):
+    summary = (
+        'The system contains unexpected GPG keys after upgrade.'
+        ' This can be caused e.g. by a manual intervention'
+        ' or by malicious attempt to hijack the upgrade process.'
+        ' The unexpected keys are the following:'
+        ' {sep}{key_list}'
+        .format(
+            sep=FMT_LIST_SEPARATOR,
+            key_list=FMT_LIST_SEPARATOR.join(unexpected_fps)
+        )
+    )
+    hint = (
+        'Verify the installed GPG keys are expected.'
+    )
+    groups = [
+        reporting.Groups.POST,
+        reporting.Groups.REPOSITORY,
+        reporting.Groups.SECURITY
+    ]
+    reporting.create_report([
+        reporting.Title('Detected unexpected GPG keys after the upgrade.'),
+        reporting.Summary(summary),
+        reporting.Severity(reporting.Severity.HIGH),
+        reporting.Groups(groups),
+        reporting.Remediation(hint=hint),
+    ])
+
+
+def process():
+    """
+    Verify the system does not have any unexpected gpg keys installed
+
+    If the --no-gpgcheck option is used, this is skipped as we can not
+    guarantee that what was installed came from trusted source
+    """
+
+    if is_nogpgcheck_set():
+        api.current_logger().warning('The --nogpgcheck option is used: Skipping the check of installed GPG keys.')
+        return
+
+    installed_fps_tuple = _get_installed_fps_tuple()
+
+    try:
+        trusted_gpg_keys = next(api.consume(TrustedGpgKeys))
+    except StopIteration:
+        # unexpected (bug) situation; keeping as seatbelt for the security aspect
+        installed_fps = ['{fp}: {packager}'.format(fp=fp, packager=packager) for fp, packager in installed_fps_tuple]
+        _report_cannot_check_keys(installed_fps)
+        return
+
+    trusted_fps = [key.fingerprint for key in trusted_gpg_keys.items]
+    unexpected_fps = []
+    for fp, packager in installed_fps_tuple:
+        if fp not in trusted_fps:
+            unexpected_fps.append('{fp}: {packager}'.format(fp=fp, packager=packager))
+
+    if unexpected_fps:
+        _report_unexpected_keys(unexpected_fps)