ssh: T2691: bugfix loglevel config migration

When migrating the conf from VyOS 1.2 to 1.3 a configuration error could appear
if the user specified "info" as loglevel instead of "INFO". There was no input
validation done in 1.2 but this is now enforced in 1.3.

In VyOS 1.3 loglevel will be always lowercase on the CLI and when migrating the
config this is transformed. Also VyOS 1.2 accpeted any arbitrary loglevel. If
an invalid loglevel is found it will be set to info.

3 files changed, 63 insertions, 8 deletions

diff --git a/data/templates/ssh/sshd_config.tmpl b/data/templates/ssh/sshd_config.tmpl
index dbc5c3646..4fde24255 100644
--- a/data/templates/ssh/sshd_config.tmpl
+++ b/data/templates/ssh/sshd_config.tmpl
@@ -46,7 +46,7 @@ Port {{ value }}
 {% endif %}
 
 # Gives the verbosity level that is used when logging messages from sshd
-LogLevel {{ loglevel }}
+LogLevel {{ loglevel | upper }}
 
 # Specifies whether password authentication is allowed
 PasswordAuthentication {{ "no" if disable_password_authentication is defined else "yes" }}
diff --git a/interface-definitions/ssh.xml.in b/interface-definitions/ssh.xml.in
index 1b20f5776..d253c2f34 100644
--- a/interface-definitions/ssh.xml.in
+++ b/interface-definitions/ssh.xml.in
@@ -132,30 +132,30 @@
             <properties>
               <help>Log level</help>
               <completionHelp>
-                <list>QUIET FATAL ERROR INFO VERBOSE</list>
+                <list>quiet fatal error info verbose</list>
               </completionHelp>
               <valueHelp>
-                <format>QUIET</format>
+                <format>quiet</format>
                 <description>stay silent</description>
               </valueHelp>
               <valueHelp>
-                <format>FATAL</format>
+                <format>fatal</format>
                 <description>log fatals only</description>
               </valueHelp>
               <valueHelp>
-                <format>ERROR</format>
+                <format>error</format>
                 <description>log errors and fatals only</description>
               </valueHelp>
               <valueHelp>
-                <format>INFO</format>
+                <format>info</format>
                 <description>default log level</description>
               </valueHelp>
               <valueHelp>
-                <format>VERBOSE</format>
+                <format>verbose</format>
                 <description>enable logging of failed login attempts</description>
               </valueHelp>
               <constraint>
-                <regex>^(QUIET|FATAL|ERROR|INFO|VERBOSE)$</regex>
+                <regex>^(quiet|fatal|error|info|verbose)$</regex>
               </constraint>
             </properties>
             <defaultValue>INFO</defaultValue>
diff --git a/src/migration-scripts/ssh/1-to-2 b/src/migration-scripts/ssh/1-to-2
new file mode 100755
index 000000000..bc8815753
--- /dev/null
+++ b/src/migration-scripts/ssh/1-to-2
@@ -0,0 +1,55 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2020 VyOS maintainers and contributors
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 or later as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# VyOS 1.2 crux allowed configuring a lower or upper case loglevel. This
+# is no longer supported as the input data is validated and will lead to
+# an error. If user specifies an upper case logleve, make it lowercase
+
+from sys import argv,exit
+from vyos.configtree import ConfigTree
+
+if (len(argv) < 1):
+    print("Must specify file name!")
+    exit(1)
+
+file_name = argv[1]
+
+with open(file_name, 'r') as f:
+    config_file = f.read()
+
+base = ['service', 'ssh', 'loglevel']
+config = ConfigTree(config_file)
+
+if not config.exists(base):
+    # Nothing to do
+    exit(0)
+else:
+    # red in configured loglevel and convert it to lower case
+    tmp = config.return_value(base).lower()
+
+    # VyOS 1.2 had no proper value validation on the CLI thus the
+    # user could use any arbitrary values - sanitize them
+    if tmp not in ['quiet', 'fatal', 'error', 'info', 'verbose']:
+        tmp = 'info'
+
+    config.set(base, value=tmp)
+
+    try:
+        with open(file_name, 'w') as f:
+            f.write(config.to_string())
+    except OSError as e:
+        print("Failed to save the modified config: {}".format(e))
+        exit(1)