Enhancements to allow custom umask usage while executing plugins (son…

…ic-net#42)

 - Use default umask value of 022 to execute ztp plugins

 - User can provide a custom umask octal value string as part of plugin data if a specific umask is required. { "plugin" : { "url" : "http://10.1.1.1/plugins/my-plugin", "umask" : "177" } }

 - Firmware plugin has been modified to always use 022 umask when installing sonic image

 - Added unit test cases to test user specified umask value

src/usr/lib/python3/dist-packages/ztp/ZTPLib.py

@@ -58,7 +58,7 @@ def getTimestamp():
 ## Global variable to keep track of the pid or process created by runCommand()
 runcmd_pids = []
 
-def runCommand(cmd, capture_stdout=True, use_shell=False):
+def runCommand(cmd, capture_stdout=True, use_shell=False, umask=-1):
     '''!
     Execute a given command
 
@@ -95,7 +95,7 @@ def runCommand(cmd, capture_stdout=True, use_shell=False):
             else:
                 shcmd = cmd
         if capture_stdout is True:
-            proc = subprocess.Popen(shcmd, shell=use_shell, stdout=subprocess.PIPE, stderr=subprocess.PIPE, close_fds=True)
+            proc = subprocess.Popen(shcmd, shell=use_shell, stdout=subprocess.PIPE, stderr=subprocess.PIPE, close_fds=True, umask=umask)
             pid = proc.pid
             runcmd_pids.append(pid)
             output_stdout, output_stderr = proc.communicate()
@@ -109,7 +109,7 @@ def runCommand(cmd, capture_stdout=True, use_shell=False):
                 list_stderr.append(str(l.decode()))
             return (proc.returncode, list_stdout, list_stderr)
         else:
-            proc = subprocess.Popen(shcmd, shell=use_shell)
+            proc = subprocess.Popen(shcmd, shell=use_shell, umask=umask)
             pid = proc.pid
             runcmd_pids.append(pid)
             proc.communicate()

src/usr/lib/python3/dist-packages/ztp/defaults.py

@@ -59,6 +59,7 @@
   "section-input-file"   : "input.json", \
   "sighandler-wait-interval" : 60, \
   "test-mode"            : False, \
+  "umask"                : "022", \
   "ztp-activity"         : '/var/run/ztp/activity', \
   "ztp-cfg-dir"          : "/host/ztp", \
   "ztp-json"             : "/host/ztp/ztp_data.json", \

src/usr/lib/ztp/plugins/firmware

@@ -379,7 +379,7 @@ class Firmware:
         # Execute sonic-installer command
         logger.info('firmware: Installing firmware image located at \'%s\'.' % self.__dest_file)
         updateActivity('firmware: Installing firmware image located at \'%s\'.' % self.__dest_file)
-        rc = runCommand(cmd, capture_stdout=False)
+        rc = runCommand(cmd, capture_stdout=False, umask=0o022)
         if rc != 0:
             self.__bailout('Error (%d) encountered while processing command : %s' % (cmd))
 

src/usr/lib/ztp/ztp-engine.py

@@ -498,6 +498,13 @@ def __processConfigSections(self):
                         # Determine if shell has to be used to execute plugin
                         _shell = getField(plugin_data, 'shell', bool, False)
 
+                        # Determine if user specified umask has to be used to execute plugin
+                        try:
+                            _umask = int(getField(plugin_data, 'umask', str, getCfg("umask")), 8)
+                        except Exception as e:
+                            logger.error('Exception[%s] encountered while reading umask to execute the plugin for %s. Using default value -1.' % (str(e), sec))
+                            _umask = -1
+
                         # Construct the full plugin command string along with arguments
                         plugin_cmd = plugin
                         if plugin_args is not None:
@@ -506,7 +513,7 @@ def __processConfigSections(self):
                         # A plugin has been resolved and its input configuration section data as well
                         logger.debug('Executing plugin %s.' % (plugin_cmd))
                         # Execute identified plugin
-                        rc = runCommand(plugin_cmd, capture_stdout=False, use_shell=_shell)
+                        rc = runCommand(plugin_cmd, capture_stdout=False, use_shell=_shell, umask=_umask)
 
                         logger.debug('Plugin %s exit code = %d.' % (plugin_cmd, rc))
                         # Compare plugin exit code

tests/test_ZTPLib.py

@@ -41,6 +41,14 @@ def test_cmd(self, tmpdir):
         assert((cmd_stdout1 == cmd_stdout2) and (cmd_stdout2 == cmd_stdout3) and (cmd_stdout3 == cmd_stdout4))
         assert((cmd_stderr1 == cmd_stderr2) and (cmd_stderr2 == cmd_stderr3) and (cmd_stderr3 == cmd_stderr4))
 
+        (rc5, cmd_stdout5, cmd_stderr5) = runCommand(['touch', '/tmp/test_file_644'], use_shell=True, umask=0o022)
+        st = os.stat('/tmp/test_file_644')
+        assert(0o644, oct(st.st_mode))
+        (rc6, cmd_stdout6, cmd_stderr6) = runCommand(['touch', '/tmp/test_file_600'], use_shell=True, umask=0o177)
+        st = os.stat('/tmp/test_file_600')
+        assert(0o600, oct(st.st_mode))
+        runCommand("rm -f /tmp/test_file_644 /tmp/test_file_600")
+
         (rc1, cmd_stdout1, cmd_stderr1) = runCommand('ps hjk')
         (rc2, cmd_stdout2, cmd_stderr2) = runCommand('ps hjk', use_shell=True)
         (rc3, cmd_stdout3, cmd_stderr3) = runCommand(['ps', 'hjk'])

tests/test_ztp_engine.py

@@ -181,6 +181,22 @@ def test_ztp_json(self):
            "message-file" : "/etc/ztp.results",
            "fail" : false,
            "status" : "DISABLED"
+        },
+        "0005-test-plugin": {
+           "plugin" : {
+             "name" : "test-plugin",
+             "umask" : "177"
+           },
+           "message" : "umask-check",
+           "message-file" : "/tmp/test_plugin_umask_600"
+        },
+        "0006-test-plugin": {
+           "plugin" : {
+             "name" : "test-plugin",
+             "umask" : "177"
+           },
+           "message" : "umask-check",
+           "message-file" : "/tmp/test_plugin_umask_644"
         }
     }
 }"""
@@ -219,6 +235,13 @@ def test_ztp_json(self):
         assert(jsonDict.get('ztp').get('0004-test-plugin').get('timestamp') != None)
         assert(jsonDict.get('ztp').get('0004-test-plugin').get('exit-code') == 0)
 
+        st = os.stat("/tmp/test_plugin_umask_600")
+        assert(0o600, oct(st.st_mode))
+
+        st = os.stat("/tmp/test_plugin_umask_644")
+        assert(0o644, oct(st.st_mode))
+        runCommand("rm -f /tmp/test_plugin_umask_600 /tmp/test_plugin_umask_644")
+
         old_timestamp = jsonDict.get('ztp').get('timestamp')
         runCommand(COVERAGE + ZTP_ENGINE_CMD)
         runCommand(COVERAGE + ZTP_CMD + ' status -v')