qvm-template: verify template package signature directly at download

Make the download() function save the package into a temporary space and
move to the target location only after checking the signature. This is
safer option than requiring all callers to explicitly verify the
signature. Also, make the download() function verify if the template
name inside the package matches what was requested.
Especially, make `qvm-template download` action verify the signature
too.

On `qvm-template install` avoid checking the signature again for
downloaded packages, by passing extra argument to the verify_rpm()
function. But still verify signature of packages loaded from disk.

qubesadmin/tests/tools/qvm_template.py

@@ -1,3 +1,4 @@
+import re
 from unittest import mock
 import argparse
 import asyncio
@@ -14,6 +15,13 @@ import rpm
 import qubesadmin.tests
 import qubesadmin.tools.qvm_template
 
+class re_str(str):
+    def __eq__(self, other):
+        return bool(re.match(self, other))
+
+    def __hash__(self):
+        return super().__hash__()
+
 class TC_00_qvm_template(qubesadmin.tests.QubesTestCase):
     def setUp(self):
         # Print str(list) directly so that the output is consistent no matter
@@ -248,7 +256,7 @@ class TC_00_qvm_template(qubesadmin.tests.QubesTestCase):
             path = template_file.name
             args = argparse.Namespace(
                 templates=[path],
-                keyring='/tmp',
+                keyring='/tmp/keyring.gpg',
                 nogpgcheck=False,
                 cachedir='/var/cache/qvm-template',
                 repo_files=[],
@@ -267,8 +275,9 @@ class TC_00_qvm_template(qubesadmin.tests.QubesTestCase):
         ])
         # Nothing downloaded
         mock_dl.assert_called_with(args, self.app,
-            path_override='/var/tmp/qvm-template-tmpdir',
-            dl_list={}, suffix='.unverified', version_selector=selector)
+            dl_list={}, version_selector=selector)
+        mock_verify.assert_called_once_with(template_file.name, '/tmp/keyring.gpg',
+            nogpgcheck=False)
         # Package is extracted
         mock_extract.assert_called_with('test-vm', path,
             '/var/tmp/qvm-template-tmpdir')
@@ -375,8 +384,7 @@ class TC_00_qvm_template(qubesadmin.tests.QubesTestCase):
         ])
         # Nothing downloaded
         mock_dl.assert_called_with(args, self.app,
-            path_override='/var/tmp/qvm-template-tmpdir',
-            dl_list={}, suffix='.unverified', version_selector=selector)
+            dl_list={}, version_selector=selector)
         # Package is extracted
         mock_extract.assert_called_with('test-vm', path,
             '/var/tmp/qvm-template-tmpdir')
@@ -520,8 +528,8 @@ class TC_00_qvm_template(qubesadmin.tests.QubesTestCase):
         ])
         # Nothing downloaded
         self.assertEqual(mock_dl.mock_calls, [
-            mock.call(args, self.app, path_override='/var/tmp/qvm-template-tmpdir',
-                dl_list={}, suffix='.unverified', version_selector=selector)
+            mock.call(args, self.app,
+                dl_list={}, version_selector=selector)
         ])
         # Should not be executed:
         self.assertEqual(mock_extract.mock_calls, [])
@@ -644,6 +652,119 @@ class TC_00_qvm_template(qubesadmin.tests.QubesTestCase):
         self.assertEqual(mock_rename.mock_calls, [])
         self.assertAllCalled()
 
+    @mock.patch('os.rename')
+    @mock.patch('os.makedirs')
+    @mock.patch('subprocess.check_call')
+    @mock.patch('qubesadmin.tools.qvm_template.confirm_action')
+    @mock.patch('qubesadmin.tools.qvm_template.extract_rpm')
+    @mock.patch('qubesadmin.tools.qvm_template.download')
+    @mock.patch('qubesadmin.tools.qvm_template.get_dl_list')
+    @mock.patch('qubesadmin.tools.qvm_template.verify_rpm')
+    def test_107_install_download_success(
+            self,
+            mock_verify,
+            mock_dl_list,
+            mock_dl,
+            mock_extract,
+            mock_confirm,
+            mock_call,
+            mock_mkdirs,
+            mock_rename):
+        self.app.expected_calls[('dom0', 'admin.vm.List', None, None)] = b'0\0'
+        build_time = '2020-09-01 14:30:00' # 1598970600
+        install_time = '2020-09-01 15:30:00'
+        for key, val in [
+                ('name', 'test-vm'),
+                ('epoch', '2'),
+                ('version', '4.1'),
+                ('release', '2020'),
+                ('reponame', 'qubes-templates-itl'),
+                ('buildtime', build_time),
+                ('installtime', install_time),
+                ('license', 'GPL'),
+                ('url', 'https://qubes-os.org'),
+                ('summary', 'Summary'),
+                ('description', 'Desc|desc')]:
+            self.app.expected_calls[(
+                'test-vm',
+                'admin.vm.feature.Set',
+                f'template-{key}',
+                val.encode())] = b'0\0'
+        mock_dl.return_value = {'test-vm': {
+            rpm.RPMTAG_NAME        : 'qubes-template-test-vm',
+            rpm.RPMTAG_BUILDTIME   : 1598970600,
+            rpm.RPMTAG_DESCRIPTION : 'Desc\ndesc',
+            rpm.RPMTAG_EPOCHNUM    : 2,
+            rpm.RPMTAG_LICENSE     : 'GPL',
+            rpm.RPMTAG_RELEASE     : '2020',
+            rpm.RPMTAG_SUMMARY     : 'Summary',
+            rpm.RPMTAG_URL         : 'https://qubes-os.org',
+            rpm.RPMTAG_VERSION     : '4.1'
+        }}
+        dl_list = {
+            'test-vm': qubesadmin.tools.qvm_template.DlEntry(
+                ('1', '4.1', '20200101'), 'qubes-templates-itl', 1048576)
+        }
+        mock_dl_list.return_value = dl_list
+        mock_call.side_effect = self.add_new_vm_side_effect
+        mock_time = mock.Mock(wraps=datetime.datetime)
+        mock_time.now.return_value = \
+            datetime.datetime(2020, 9, 1, 15, 30, tzinfo=datetime.timezone.utc)
+        with mock.patch('qubesadmin.tools.qvm_template.LOCK_FILE', '/tmp/test.lock'), \
+                mock.patch('datetime.datetime', new=mock_time), \
+                mock.patch('tempfile.TemporaryDirectory') as mock_tmpdir, \
+                mock.patch('sys.stderr', new=io.StringIO()) as mock_err:
+            args = argparse.Namespace(
+                templates='test-vm',
+                keyring='/tmp/keyring.gpg',
+                nogpgcheck=False,
+                cachedir='/var/cache/qvm-template',
+                repo_files=[],
+                releasever='4.1',
+                yes=False,
+                keep_cache=True,
+                allow_pv=False,
+                pool=None
+            )
+            mock_tmpdir.return_value.__enter__.return_value = \
+                '/var/tmp/qvm-template-tmpdir'
+            qubesadmin.tools.qvm_template.install(args, self.app)
+        # Attempt to get download list
+        selector = qubesadmin.tools.qvm_template.VersionSelector.LATEST
+        self.assertEqual(mock_dl_list.mock_calls, [
+            mock.call(args, self.app, version_selector=selector)
+        ])
+        # Nothing downloaded
+        mock_dl.assert_called_with(args, self.app,
+            dl_list=dl_list, version_selector=selector)
+        # download already verify the package internally
+        self.assertEqual(mock_verify.mock_calls, [])
+        # Package is extracted
+        mock_extract.assert_called_with('test-vm',
+            '/var/cache/qvm-template/qubes-template-test-vm-1:4.1-20200101.rpm',
+            '/var/tmp/qvm-template-tmpdir')
+        # No packages overwritten, so no confirm needed
+        self.assertEqual(mock_confirm.mock_calls, [])
+        # qvm-template-postprocess is called
+        self.assertEqual(mock_call.mock_calls, [
+            mock.call([
+                'qvm-template-postprocess',
+                '--really',
+                '--no-installed-by-rpm',
+                'post-install',
+                'test-vm',
+                '/var/tmp/qvm-template-tmpdir'
+                    '/var/lib/qubes/vm-templates/test-vm'
+            ])
+        ])
+        # Cache directory created
+        self.assertEqual(mock_mkdirs.mock_calls, [
+            mock.call(args.cachedir, exist_ok=True)
+        ])
+        # No templates downloaded, thus no renames needed
+        self.assertEqual(mock_rename.mock_calls, [])
+        self.assertAllCalled()
+
     def test_110_qrexec_payload_refresh_success(self):
         with tempfile.NamedTemporaryFile() as repo_conf1, \
                 tempfile.NamedTemporaryFile() as repo_conf2:
@@ -3188,11 +3309,27 @@ test-vm : Qubes template for fedora-31
         ])
         self.assertAllCalled()
 
+    def _mock_qrexec_download(self, args, app, spec, path,
+                              dlsize=None, refresh=False):
+        self.assertFalse(os.path.exists(path),
+            '{} should not exist before'.format(path))
+        # just create an empty file
+        with open(path, 'wb') as f:
+            if f is not None:
+                f.truncate(dlsize)
+
+    @mock.patch('qubesadmin.tools.qvm_template.verify_rpm')
     @mock.patch('qubesadmin.tools.qvm_template.get_dl_list')
     @mock.patch('qubesadmin.tools.qvm_template.qrexec_download')
-    def test_180_download_success(self, mock_qrexec, mock_dllist):
+    def test_180_download_success(self, mock_qrexec, mock_dllist,
+                                  mock_verify_rpm):
+        mock_qrexec.side_effect = self._mock_qrexec_download
         with tempfile.TemporaryDirectory() as dir:
             args = argparse.Namespace(
+                repo_files=[],
+                keyring='/tmp/keyring.gpg',
+                releasever='4.1',
+                nogpgcheck=False,
                 retries=1
             )
             qubesadmin.tools.qvm_template.download(args, self.app, dir, {
@@ -3202,25 +3339,36 @@ test-vm : Qubes template for fedora-31
                         ('0', '1', '2'),
                         'qubes-templates-itl-testing',
                         2048576)
-                }, '.unverified')
+                })
             self.assertEqual(mock_qrexec.mock_calls, [
                 mock.call(args, self.app, 'qubes-template-fedora-31-1:2-3',
-                    dir + '/qubes-template-fedora-31-1:2-3.rpm.unverified',
+                    re_str(dir + '/.*/qubes-template-fedora-31-1:2-3.rpm.UNTRUSTED'),
                     1048576),
                 mock.call(args, self.app, 'qubes-template-fedora-32-0:1-2',
-                    dir + '/qubes-template-fedora-32-0:1-2.rpm.unverified',
+                    re_str(dir + '/.*/qubes-template-fedora-32-0:1-2.rpm.UNTRUSTED'),
                     2048576)
             ])
             self.assertEqual(mock_dllist.mock_calls, [])
-            self.assertTrue(all(
-                [x.endswith('.unverified') for x in os.listdir(dir)]))
+            self.assertEqual(mock_verify_rpm.mock_calls, [
+                mock.call(re_str(dir + '/.*/qubes-template-fedora-31-1:2-3.rpm.UNTRUSTED'),
+                          '/tmp/keyring.gpg', template_name='fedora-31'),
+                mock.call(re_str(dir + '/.*/qubes-template-fedora-32-0:1-2.rpm.UNTRUSTED'),
+                          '/tmp/keyring.gpg', template_name='fedora-32'),
+            ])
 
+    @mock.patch('qubesadmin.tools.qvm_template.verify_rpm')
     @mock.patch('qubesadmin.tools.qvm_template.get_dl_list')
     @mock.patch('qubesadmin.tools.qvm_template.qrexec_download')
-    def test_181_download_success_nosuffix(self, mock_qrexec, mock_dllist):
+    def test_181_download_success_nosuffix(self, mock_qrexec, mock_dllist,
+                                           mock_verify_rpm):
+        mock_qrexec.side_effect = self._mock_qrexec_download
         with tempfile.TemporaryDirectory() as dir:
             args = argparse.Namespace(
                 retries=1,
+                repo_files=[],
+                keyring='/tmp/keyring.gpg',
+                releasever='4.1',
+                nogpgcheck=False,
                 downloaddir=dir
             )
             with mock.patch('sys.stderr', new=io.StringIO()) as mock_err:
@@ -3230,28 +3378,39 @@ test-vm : Qubes template for fedora-31
                     })
             self.assertEqual(mock_qrexec.mock_calls, [
                 mock.call(args, self.app, 'qubes-template-fedora-31-1:2-3',
-                    dir + '/qubes-template-fedora-31-1:2-3.rpm',
+                    re_str(dir + '/.*/qubes-template-fedora-31-1:2-3.rpm.UNTRUSTED'),
                     1048576)
             ])
             self.assertEqual(mock_dllist.mock_calls, [])
+            self.assertEqual(mock_verify_rpm.mock_calls, [
+                mock.call(re_str(dir + '/.*/qubes-template-fedora-31-1:2-3.rpm.UNTRUSTED'),
+                          '/tmp/keyring.gpg', template_name='fedora-31'),
+            ])
 
+    @mock.patch('qubesadmin.tools.qvm_template.verify_rpm')
     @mock.patch('qubesadmin.tools.qvm_template.get_dl_list')
     @mock.patch('qubesadmin.tools.qvm_template.qrexec_download')
-    def test_182_download_success_getdllist(self, mock_qrexec, mock_dllist):
+    def test_182_download_success_getdllist(self, mock_qrexec, mock_dllist,
+                                            mock_verify_rpm):
+        mock_qrexec.side_effect = self._mock_qrexec_download
         mock_dllist.return_value = {
             'fedora-31': qubesadmin.tools.qvm_template.DlEntry(
                 ('1', '2', '3'), 'qubes-templates-itl', 1048576)
         }
         with tempfile.TemporaryDirectory() as dir:
             args = argparse.Namespace(
-                retries=1
+                retries=1,
+                repo_files=[],
+                keyring='/tmp/keyring.gpg',
+                releasever='4.1',
+                nogpgcheck=False,
             )
             qubesadmin.tools.qvm_template.download(args, self.app,
-                dir, None, '.unverified',
+                dir, None,
                 qubesadmin.tools.qvm_template.VersionSelector.LATEST_LOWER)
             self.assertEqual(mock_qrexec.mock_calls, [
                 mock.call(args, self.app, 'qubes-template-fedora-31-1:2-3',
-                    dir + '/qubes-template-fedora-31-1:2-3.rpm.unverified',
+                    re_str(dir + '/.*/qubes-template-fedora-31-1:2-3.rpm.UNTRUSTED'),
                     1048576)
             ])
             self.assertEqual(mock_dllist.mock_calls, [
@@ -3260,40 +3419,54 @@ test-vm : Qubes template for fedora-31
                         qubesadmin.tools.qvm_template.\
                         VersionSelector.LATEST_LOWER)
             ])
-            self.assertTrue(all(
-                [x.endswith('.unverified') for x in os.listdir(dir)]))
+            self.assertEqual(mock_verify_rpm.mock_calls, [
+                mock.call(re_str(dir + '/.*/qubes-template-fedora-31-1:2-3.rpm.UNTRUSTED'),
+                          '/tmp/keyring.gpg', template_name='fedora-31'),
+            ])
 
+    @mock.patch('qubesadmin.tools.qvm_template.verify_rpm')
     @mock.patch('qubesadmin.tools.qvm_template.get_dl_list')
     @mock.patch('qubesadmin.tools.qvm_template.qrexec_download')
-    def test_183_download_success_downloaddir(self, mock_qrexec, mock_dllist):
+    def test_183_download_success_downloaddir(self, mock_qrexec, mock_dllist,
+                                              mock_verify_rpm):
+        mock_qrexec.side_effect = self._mock_qrexec_download
         with tempfile.TemporaryDirectory() as dir:
             args = argparse.Namespace(
                 retries=1,
+                repo_files=[],
+                keyring='/tmp/keyring.gpg',
+                releasever='4.1',
+                nogpgcheck=False,
                 downloaddir=dir
             )
             qubesadmin.tools.qvm_template.download(args, self.app, None, {
                     'fedora-31': qubesadmin.tools.qvm_template.DlEntry(
                         ('1', '2', '3'), 'qubes-templates-itl', 1048576)
-                }, '.unverified')
+                })
             self.assertEqual(mock_qrexec.mock_calls, [
                 mock.call(args, self.app, 'qubes-template-fedora-31-1:2-3',
-                    dir + '/qubes-template-fedora-31-1:2-3.rpm.unverified',
+                    re_str(dir + '/.*/qubes-template-fedora-31-1:2-3.rpm.UNTRUSTED'),
                     1048576)
             ])
             self.assertEqual(mock_dllist.mock_calls, [])
-            self.assertTrue(all(
-                [x.endswith('.unverified') for x in os.listdir(dir)]))
 
+    @mock.patch('qubesadmin.tools.qvm_template.verify_rpm')
     @mock.patch('qubesadmin.tools.qvm_template.get_dl_list')
     @mock.patch('qubesadmin.tools.qvm_template.qrexec_download')
-    def test_184_download_success_exists(self, mock_qrexec, mock_dllist):
+    def test_184_download_success_exists(self, mock_qrexec, mock_dllist,
+                                         mock_verify_rpm):
+        mock_qrexec.side_effect = self._mock_qrexec_download
         with tempfile.TemporaryDirectory() as dir:
             with open(os.path.join(
-                        dir, 'qubes-template-fedora-31-1:2-3.rpm.unverified'),
+                        dir, 'qubes-template-fedora-31-1:2-3.rpm'),
                     'w') as _:
                 pass
             args = argparse.Namespace(
                 retries=1,
+                repo_files=[],
+                keyring='/tmp/keyring.gpg',
+                releasever='4.1',
+                nogpgcheck=False,
                 downloaddir=dir
             )
             with mock.patch('sys.stderr', new=io.StringIO()) as mock_err:
@@ -3304,21 +3477,22 @@ test-vm : Qubes template for fedora-31
                             ('0', '1', '2'),
                             'qubes-templates-itl-testing',
                             2048576)
-                    }, '.unverified')
+                    })
                 self.assertTrue('already exists, skipping'
                     in mock_err.getvalue())
             self.assertEqual(mock_qrexec.mock_calls, [
                 mock.call(args, self.app, 'qubes-template-fedora-32-0:1-2',
-                    dir + '/qubes-template-fedora-32-0:1-2.rpm.unverified',
+                    re_str(dir + '/.*/qubes-template-fedora-32-0:1-2.rpm.UNTRUSTED'),
                     2048576)
             ])
             self.assertEqual(mock_dllist.mock_calls, [])
-            self.assertTrue(all(
-                [x.endswith('.unverified') for x in os.listdir(dir)]))
 
+    @mock.patch('qubesadmin.tools.qvm_template.verify_rpm')
     @mock.patch('qubesadmin.tools.qvm_template.get_dl_list')
     @mock.patch('qubesadmin.tools.qvm_template.qrexec_download')
-    def test_185_download_success_existsmove(self, mock_qrexec, mock_dllist):
+    def test_185_download_success_existsmove(self, mock_qrexec, mock_dllist,
+                                             mock_verify_rpm):
+        mock_qrexec.side_effect = self._mock_qrexec_download
         with tempfile.TemporaryDirectory() as dir:
             with open(os.path.join(
                         dir, 'qubes-template-fedora-31-1:2-3.rpm'),
@@ -3326,25 +3500,30 @@ test-vm : Qubes template for fedora-31
                 pass
             args = argparse.Namespace(
                 retries=1,
+                repo_files=[],
+                keyring='/tmp/keyring.gpg',
+                releasever='4.1',
+                nogpgcheck=False,
                 downloaddir=dir
             )
             with mock.patch('sys.stderr', new=io.StringIO()) as mock_err:
                 qubesadmin.tools.qvm_template.download(args, self.app, None, {
                         'fedora-31': qubesadmin.tools.qvm_template.DlEntry(
                             ('1', '2', '3'), 'qubes-templates-itl', 1048576)
-                    }, '.unverified')
+                    })
                 self.assertTrue('already exists, skipping'
                     in mock_err.getvalue())
             self.assertEqual(mock_qrexec.mock_calls, [])
             self.assertEqual(mock_dllist.mock_calls, [])
             self.assertTrue(os.path.exists(
-                dir + '/qubes-template-fedora-31-1:2-3.rpm.unverified'))
-            self.assertTrue(all(
-                [x.endswith('.unverified') for x in os.listdir(dir)]))
+                dir + '/qubes-template-fedora-31-1:2-3.rpm'))
 
+    @mock.patch('qubesadmin.tools.qvm_template.verify_rpm')
     @mock.patch('qubesadmin.tools.qvm_template.get_dl_list')
     @mock.patch('qubesadmin.tools.qvm_template.qrexec_download')
-    def test_186_download_success_existsnosuffix(self, mock_qrexec, mock_dllist):
+    def test_186_download_success_existsnosuffix(self, mock_qrexec, mock_dllist,
+                                                 mock_verify_rpm):
+        mock_qrexec.side_effect = self._mock_qrexec_download
         with tempfile.TemporaryDirectory() as dir:
             with open(os.path.join(
                         dir, 'qubes-template-fedora-31-1:2-3.rpm'),
@@ -3352,6 +3531,10 @@ test-vm : Qubes template for fedora-31
                 pass
             args = argparse.Namespace(
                 retries=1,
+                repo_files=[],
+                keyring='/tmp/keyring.gpg',
+                releasever='4.1',
+                nogpgcheck=False,
                 downloaddir=dir
             )
             with mock.patch('sys.stderr', new=io.StringIO()) as mock_err:
@@ -3366,19 +3549,26 @@ test-vm : Qubes template for fedora-31
             self.assertTrue(os.path.exists(
                 dir + '/qubes-template-fedora-31-1:2-3.rpm'))
 
+    @mock.patch('qubesadmin.tools.qvm_template.verify_rpm')
     @mock.patch('qubesadmin.tools.qvm_template.get_dl_list')
     @mock.patch('qubesadmin.tools.qvm_template.qrexec_download')
-    def test_187_download_success_retry(self, mock_qrexec, mock_dllist):
+    def test_187_download_success_retry(self, mock_qrexec, mock_dllist,
+                                        mock_verify_rpm):
         counter = 0
-        def f(*args):
+        def f(*args, **kwargs):
             nonlocal counter
             counter += 1
             if counter == 1:
                 raise ConnectionError
+            self._mock_qrexec_download(*args, **kwargs)
         mock_qrexec.side_effect = f
         with tempfile.TemporaryDirectory() as dir:
             args = argparse.Namespace(
                 retries=2,
+                repo_files=[],
+                keyring='/tmp/keyring.gpg',
+                releasever='4.1',
+                nogpgcheck=False,
                 downloaddir=dir
             )
             with mock.patch('sys.stderr', new=io.StringIO()) as mock_err, \
@@ -3389,31 +3579,39 @@ test-vm : Qubes template for fedora-31
                     })
                 self.assertTrue('retrying...' in mock_err.getvalue())
                 self.assertEqual(mock_rm.mock_calls, [
-                    mock.call(dir + '/qubes-template-fedora-31-1:2-3.rpm')
+                    mock.call(re_str(dir + '/.*/qubes-template-fedora-31-1:2-3.rpm.UNTRUSTED'))
                 ])
             self.assertEqual(mock_qrexec.mock_calls, [
                 mock.call(args, self.app, 'qubes-template-fedora-31-1:2-3',
-                    dir + '/qubes-template-fedora-31-1:2-3.rpm',
+                    re_str(dir + '/.*/qubes-template-fedora-31-1:2-3.rpm.UNTRUSTED'),
                     1048576),
                 mock.call(args, self.app, 'qubes-template-fedora-31-1:2-3',
-                    dir + '/qubes-template-fedora-31-1:2-3.rpm',
+                    re_str(dir + '/.*/qubes-template-fedora-31-1:2-3.rpm.UNTRUSTED'),
                     1048576)
             ])
             self.assertEqual(mock_dllist.mock_calls, [])
 
+    @mock.patch('qubesadmin.tools.qvm_template.verify_rpm')
     @mock.patch('qubesadmin.tools.qvm_template.get_dl_list')
     @mock.patch('qubesadmin.tools.qvm_template.qrexec_download')
-    def test_188_download_fail_retry(self, mock_qrexec, mock_dllist):
+    def test_188_download_fail_retry(self, mock_qrexec, mock_dllist,
+                                     mock_verify_rpm):
+        mock_qrexec.side_effect = self._mock_qrexec_download
         counter = 0
-        def f(*args):
+        def f(*args, **kwargs):
             nonlocal counter
             counter += 1
             if counter <= 3:
                 raise ConnectionError
+            self._mock_qrexec_download(*args, **kwargs)
         mock_qrexec.side_effect = f
         with tempfile.TemporaryDirectory() as dir:
             args = argparse.Namespace(
                 retries=3,
+                repo_files=[],
+                keyring='/tmp/keyring.gpg',
+                releasever='4.1',
+                nogpgcheck=False,
                 downloaddir=dir
             )
             with mock.patch('sys.stderr', new=io.StringIO()) as mock_err, \
@@ -3427,32 +3625,38 @@ test-vm : Qubes template for fedora-31
                 self.assertEqual(mock_err.getvalue().count('retrying...'), 2)
                 self.assertTrue('download failed' in mock_err.getvalue())
                 self.assertEqual(mock_rm.mock_calls, [
-                    mock.call(dir + '/qubes-template-fedora-31-1:2-3.rpm'),
-                    mock.call(dir + '/qubes-template-fedora-31-1:2-3.rpm'),
-                    mock.call(dir + '/qubes-template-fedora-31-1:2-3.rpm')
+                    mock.call(re_str(dir + '/.*/qubes-template-fedora-31-1:2-3.rpm.UNTRUSTED')),
+                    mock.call(re_str(dir + '/.*/qubes-template-fedora-31-1:2-3.rpm.UNTRUSTED')),
+                    mock.call(re_str(dir + '/.*/qubes-template-fedora-31-1:2-3.rpm.UNTRUSTED'))
                 ])
             self.assertEqual(mock_qrexec.mock_calls, [
                 mock.call(args, self.app, 'qubes-template-fedora-31-1:2-3',
-                    dir + '/qubes-template-fedora-31-1:2-3.rpm',
+                    re_str(dir + '/.*/qubes-template-fedora-31-1:2-3.rpm.UNTRUSTED'),
                     1048576),
                 mock.call(args, self.app, 'qubes-template-fedora-31-1:2-3',
-                    dir + '/qubes-template-fedora-31-1:2-3.rpm',
+                    re_str(dir + '/.*/qubes-template-fedora-31-1:2-3.rpm.UNTRUSTED'),
                     1048576),
                 mock.call(args, self.app, 'qubes-template-fedora-31-1:2-3',
-                    dir + '/qubes-template-fedora-31-1:2-3.rpm',
+                    re_str(dir + '/.*/qubes-template-fedora-31-1:2-3.rpm.UNTRUSTED'),
                     1048576)
             ])
             self.assertEqual(mock_dllist.mock_calls, [])
 
+    @mock.patch('qubesadmin.tools.qvm_template.verify_rpm')
     @mock.patch('qubesadmin.tools.qvm_template.get_dl_list')
     @mock.patch('qubesadmin.tools.qvm_template.qrexec_download')
-    def test_189_download_fail_interrupt(self, mock_qrexec, mock_dllist):
+    def test_189_download_fail_interrupt(self, mock_qrexec, mock_dllist,
+                                         mock_verify_rpm):
         def f(*args):
             raise RuntimeError
         mock_qrexec.side_effect = f
         with tempfile.TemporaryDirectory() as dir:
             args = argparse.Namespace(
                 retries=3,
+                repo_files=[],
+                keyring='/tmp/keyring.gpg',
+                releasever='4.1',
+                nogpgcheck=False,
                 downloaddir=dir
             )
             with mock.patch('sys.stderr', new=io.StringIO()) as mock_err, \
@@ -3463,12 +3667,45 @@ test-vm : Qubes template for fedora-31
                             'fedora-31': qubesadmin.tools.qvm_template.DlEntry(
                                 ('1', '2', '3'), 'qubes-templates-itl', 1048576)
                         })
-                self.assertEqual(mock_rm.mock_calls, [
-                    mock.call(dir + '/qubes-template-fedora-31-1:2-3.rpm')
-                ])
             self.assertEqual(mock_qrexec.mock_calls, [
                 mock.call(args, self.app, 'qubes-template-fedora-31-1:2-3',
-                    dir + '/qubes-template-fedora-31-1:2-3.rpm',
+                    re_str(dir + '/.*/qubes-template-fedora-31-1:2-3.rpm'),
                     1048576)
             ])
             self.assertEqual(mock_dllist.mock_calls, [])
+
+    @mock.patch('qubesadmin.tools.qvm_template.verify_rpm')
+    @mock.patch('qubesadmin.tools.qvm_template.get_dl_list')
+    @mock.patch('qubesadmin.tools.qvm_template.qrexec_download')
+    def test_189_download_verify_fail(self, mock_qrexec, mock_dllist,
+                                         mock_verify_rpm):
+        mock_qrexec.side_effect = self._mock_qrexec_download
+        mock_verify_rpm.side_effect = \
+            qubesadmin.tools.qvm_template.SignatureVerificationError
+
+        with tempfile.TemporaryDirectory() as dir:
+            args = argparse.Namespace(
+                retries=3,
+                repo_files=[],
+                keyring='/tmp/keyring.gpg',
+                releasever='4.1',
+                nogpgcheck=False,
+                downloaddir=dir
+            )
+            with self.assertRaises(qubesadmin.tools.qvm_template.SignatureVerificationError):
+                qubesadmin.tools.qvm_template.download(
+                    args, self.app, None, {
+                        'fedora-31': qubesadmin.tools.qvm_template.DlEntry(
+                            ('1', '2', '3'), 'qubes-templates-itl', 1048576)
+                    })
+            self.assertEqual(mock_qrexec.mock_calls, [
+                mock.call(args, self.app, 'qubes-template-fedora-31-1:2-3',
+                    re_str(dir + '/.*/qubes-template-fedora-31-1:2-3.rpm'),
+                    1048576)
+            ])
+            self.assertEqual(mock_dllist.mock_calls, [])
+            self.assertEqual(os.listdir(dir), [])
+
+    # TODO: test unexpected name downloaded
+    # TODO: test truncated download
+    # TODO: test no disk space

qubesadmin/tools/qvm_template.py

@@ -146,8 +146,6 @@ def get_parser() -> argparse.ArgumentParser:
         help_str='Upgrade template packages.')
     for parser_x in [parser_install, parser_reinstall,
             parser_downgrade, parser_upgrade]:
-        parser_x.add_argument('--nogpgcheck', action='store_true',
-            help='Disable signature checks.')
         parser_x.add_argument('--allow-pv', action='store_true',
             help='Allow templates that set virt_mode to pv.')
         parser_x.add_argument('templates', nargs='*', metavar='TEMPLATESPEC')
@@ -160,6 +158,8 @@ def get_parser() -> argparse.ArgumentParser:
             help='Specify download directory.')
         parser_x.add_argument('--retries', default=5, type=int,
             help='Specify maximum number of retries for downloads.')
+        parser_x.add_argument('--nogpgcheck', action='store_true',
+            help='Disable signature checks.')
     parser_download.add_argument('templates', nargs='*',
         metavar='TEMPLATESPEC')
     # qvm-template {list,info}
@@ -602,7 +602,8 @@ def get_keys_for_repos(repo_files: typing.List[str],
 def verify_rpm(
         path: str,
         key: str,
-        nogpgcheck: bool = False
+        nogpgcheck: bool = False,
+        template_name: typing.Optional[str] = None
         ) -> rpm.hdr:
     """Verify the digest and signature of a RPM package and return the package
     header.
@@ -614,6 +615,8 @@ def verify_rpm(
 
     :param path: Location of the RPM package
     :param nogpgcheck: Whether to allow invalid GPG signatures
+    :param template_name: expected template name - if specified, verifies if
+           the package name matches expected template name
 
     :return: RPM package header. If verification fails, raises an exception.
     """
@@ -635,6 +638,10 @@ def verify_rpm(
         tset = rpm.TransactionSet()
         tset.setVSFlags(rpm.RPMVSF_MASK_NOSIGNATURES)
         hdr = tset.hdrFromFdno(fd)
+    if template_name is not None:
+        if hdr[rpm.RPMTAG_NAME] != PACKAGE_NAME_PREFIX + template_name:
+            raise SignatureVerificationError(
+                'Downloaded package does not match expected template name')
     return hdr
 
 def extract_rpm(name: str, path: str, target: str) -> bool:
@@ -759,8 +766,8 @@ def download(
         app: qubesadmin.app.QubesBase,
         path_override: typing.Optional[str] = None,
         dl_list: typing.Optional[typing.Dict[str, DlEntry]] = None,
-        suffix: str = '',
-        version_selector: VersionSelector = VersionSelector.LATEST) -> None:
+        version_selector: VersionSelector = VersionSelector.LATEST) \
+        -> typing.Dict[str, rpm.hdr]:
     """Command that downloads template packages.
 
     :param args: Arguments received by the application.
@@ -770,50 +777,65 @@ def download(
     :param dl_list: Override list of templates to download. If not set or set
         to None, ``get_dl_list`` is called, which generates the list from
         ``args``.  Optional
-    :param suffix: Suffix to add to the file name of downloaded packages. This
-        is useful if you want to distinguish between verified and unverified
-        packages. Defaults to an empty string
     :param version_selector: Specify algorithm to select the candidate version
         of a package.  Defaults to ``VersionSelector.LATEST``
+    :return package headers of downloaded templates
     """
     if dl_list is None:
         dl_list = get_dl_list(args, app, version_selector=version_selector)
 
+    keys = get_keys_for_repos(args.repo_files, args.releasever)
+
+    package_hdrs = {}
+
     path = path_override if path_override is not None else args.downloaddir
-    for name, entry in dl_list.items():
-        version_str = build_version_str(entry.evr)
-        spec = PACKAGE_NAME_PREFIX + name + '-' + version_str
-        target = os.path.join(path, '%s.rpm' % spec)
-        target_suffix = target + suffix
-        if os.path.exists(target_suffix):
-            print('\'%s\' already exists, skipping...' % target,
-                file=sys.stderr)
-        elif os.path.exists(target):
-            print('\'%s\' already exists, skipping...' % target,
-                file=sys.stderr)
-            os.rename(target, target_suffix)
-        else:
+    with tempfile.TemporaryDirectory(dir=path) as dl_dir:
+        for name, entry in dl_list.items():
+            version_str = build_version_str(entry.evr)
+            spec = PACKAGE_NAME_PREFIX + name + '-' + version_str
+            target = os.path.join(path, '%s.rpm' % spec)
+            target_temp = os.path.join(dl_dir, '%s.rpm.UNTRUSTED' % spec)
+            repo_key = keys.get(entry.reponame)
+            if repo_key is None:
+                repo_key = args.keyring
+            if os.path.exists(target):
+                print('\'%s\' already exists, skipping...' % target,
+                    file=sys.stderr)
+                # but still verify the package
+                verify_rpm(target, repo_key, template_name=name)
+                continue
             print('Downloading \'%s\'...' % spec, file=sys.stderr)
             done = False
             for attempt in range(args.retries):
                 try:
-                    qrexec_download(args, app, spec, target_suffix,
+                    qrexec_download(args, app, spec, target_temp,
                         entry.dlsize)
+                    size = os.path.getsize(target_temp)
+                    if size != entry.dlsize:
+                        raise ConnectionError(
+                            'Downloaded file is {} bytes, expected {}'.format(
+                                size, entry.dlsize))
                     done = True
                     break
                 except ConnectionError:
-                    os.remove(target_suffix)
+                    os.remove(target_temp)
                     if attempt + 1 < args.retries:
                         print('\'%s\' download failed, retrying...' % spec,
                             file=sys.stderr)
-                except:
-                    # Also remove file if interrupted by other means
-                    os.remove(target_suffix)
-                    raise
             if not done:
                 print('Error: \'%s\' download failed.' % spec, file=sys.stderr)
                 sys.exit(1)
 
+            if args.nogpgcheck:
+                print(
+                    'Warning: --nogpgcheck is ignored for downloaded templates',
+                    file=sys.stderr)
+            package_hdr = verify_rpm(target_temp, repo_key, template_name=name)
+            # after package is verified, rename to the target location
+            os.rename(target_temp, target)
+            package_hdrs[name] = package_hdr
+    return package_hdrs
+
 def locked(func):
     """Execute given function under a lock in *LOCK_FILE*"""
     @functools.wraps(func)
@@ -854,21 +876,20 @@ def install(
 
     unverified_rpm_list = [] # rpmfile, reponame
     verified_rpm_list = []
-    def verify(rpmfile, reponame, dl_dir=None):
+    def verify(rpmfile, reponame, package_hdr=None):
         """Verify package signature and version, remove "unverified"
-        suffix, and parse package header."""
-        if dl_dir:
-            path = os.path.join(
-                dl_dir, os.path.basename(rpmfile) + UNVERIFIED_SUFFIX)
-        else:
-            path = rpmfile
-
-        repo_key = keys.get(reponame)
-        if repo_key is None:
-            repo_key = args.keyring
-        package_hdr = verify_rpm(path, repo_key, args.nogpgcheck)
-        if not package_hdr:
-            parser.error('Package \'%s\' verification failed.' % rpmfile)
+        suffix, and parse package header.
+
+        If package_hdr is provided, the signature check is skipped and only
+        other checks are performed."""
+        if package_hdr is None:
+            repo_key = keys.get(reponame)
+            if repo_key is None:
+                repo_key = args.keyring
+            package_hdr = verify_rpm(rpmfile, repo_key,
+                                     nogpgcheck=args.nogpgcheck)
+            if not package_hdr:
+                parser.error('Package \'%s\' verification failed.' % rpmfile)
 
         package_name = package_hdr[rpm.RPMTAG_NAME]
         if not package_name.startswith(PACKAGE_NAME_PREFIX):
@@ -877,9 +898,6 @@ def install(
         # Remove prefix to get the real template name
         name = package_name[len(PACKAGE_NAME_PREFIX):]
 
-        if path != rpmfile:
-            os.rename(path, rpmfile)
-
         # Check if already installed
         if not override_existing and name in app.domains:
             print(('Template \'%s\' already installed, skipping...'
@@ -927,7 +945,7 @@ def install(
     # First verify local RPMs and extract header
     for rpmfile, reponame in unverified_rpm_list:
         verify(rpmfile, reponame)
-    unverified_rpm_list = []
+    unverified_rpm_list = {}
 
     os.makedirs(args.cachedir, exist_ok=True)
 
@@ -951,7 +969,7 @@ def install(
             version_str = build_version_str(entry.evr)
             target_file = \
                 '%s%s-%s.rpm' % (PACKAGE_NAME_PREFIX, name, version_str)
-            unverified_rpm_list.append(
+            unverified_rpm_list[name] = (
                 (os.path.join(args.cachedir, target_file), entry.reponame))
     dl_list = dl_list_copy
 
@@ -969,15 +987,14 @@ def install(
             'This will override changes made in the following VMs:',
             override_tpls)
 
-    with tempfile.TemporaryDirectory(dir=args.cachedir) as dl_dir:
-        download(args, app, path_override=dl_dir,
-            dl_list=dl_list, suffix=UNVERIFIED_SUFFIX,
-            version_selector=version_selector)
+    package_hdrs = download(args, app,
+        dl_list=dl_list,
+        version_selector=version_selector)
 
-        # Verify downloaded templates
-        for rpmfile, reponame in unverified_rpm_list:
-            verify(rpmfile, reponame, dl_dir=dl_dir)
-    unverified_rpm_list = []
+    # Verify downloaded templates
+    for name, (rpmfile, reponame) in unverified_rpm_list.items():
+        verify(rpmfile, reponame, package_hdrs[name])
+    del unverified_rpm_list
 
     # Unpack and install
     for rpmfile, reponame, name, package_hdr in verified_rpm_list: