1 files changed, 26 insertions, 26 deletions

diff --git a/cloudinit/net/cmdline.py b/cloudinit/net/cmdline.py
index 64e1c699..cc8dc17b 100755
--- a/cloudinit/net/cmdline.py
+++ b/cloudinit/net/cmdline.py
@@ -10,6 +10,7 @@ import base64
 import glob
 import gzip
 import io
+import logging
 import os
 
 from cloudinit import util
@@ -19,21 +20,19 @@ from . import read_sys_net_safe
 
 _OPEN_ISCSI_INTERFACE_FILE = "/run/initramfs/open-iscsi.interface"
 
+KERNEL_CMDLINE_NETWORK_CONFIG_DISABLED = "disabled"
+
 
 class InitramfsNetworkConfigSource(metaclass=abc.ABCMeta):
     """ABC for net config sources that read config written by initramfses"""
 
     @abc.abstractmethod
-    def is_applicable(self):
-        # type: () -> bool
+    def is_applicable(self) -> bool:
         """Is this initramfs config source applicable to the current system?"""
-        pass
 
     @abc.abstractmethod
-    def render_config(self):
-        # type: () -> dict
+    def render_config(self) -> dict:
         """Render a v1 network config from the initramfs configuration"""
-        pass
 
 
 class KlibcNetworkConfigSource(InitramfsNetworkConfigSource):
@@ -62,8 +61,7 @@ class KlibcNetworkConfigSource(InitramfsNetworkConfigSource):
                 if mac_addr:
                     self._mac_addrs[k] = mac_addr
 
-    def is_applicable(self):
-        # type: () -> bool
+    def is_applicable(self) -> bool:
         """
         Return whether this system has klibc initramfs network config or not
 
@@ -81,8 +79,7 @@ class KlibcNetworkConfigSource(InitramfsNetworkConfigSource):
                 return True
         return False
 
-    def render_config(self):
-        # type: () -> dict
+    def render_config(self) -> dict:
         return config_from_klibc_net_cfg(
             files=self._files, mac_addrs=self._mac_addrs,
         )
@@ -115,8 +112,8 @@ def _klibc_to_config_entry(content, mac_addrs=None):
     data = util.load_shell_content(content)
     try:
         name = data['DEVICE'] if 'DEVICE' in data else data['DEVICE6']
-    except KeyError:
-        raise ValueError("no 'DEVICE' or 'DEVICE6' entry in data")
+    except KeyError as e:
+        raise ValueError("no 'DEVICE' or 'DEVICE6' entry in data") from e
 
     # ipconfig on precise does not write PROTO
     # IPv6 config gives us IPV6PROTO, not PROTO.
@@ -233,34 +230,35 @@ def read_initramfs_config():
     return None
 
 
-def _decomp_gzip(blob, strict=True):
-    # decompress blob. raise exception if not compressed unless strict=False.
+def _decomp_gzip(blob):
+    # decompress blob or return original blob
     with io.BytesIO(blob) as iobuf:
         gzfp = None
         try:
             gzfp = gzip.GzipFile(mode="rb", fileobj=iobuf)
             return gzfp.read()
         except IOError:
-            if strict:
-                raise
             return blob
         finally:
             if gzfp:
                 gzfp.close()
 
 
-def _b64dgz(b64str, gzipped="try"):
-    # decode a base64 string.  If gzipped is true, transparently uncompresss
-    # if gzipped is 'try', then try gunzip, returning the original on fail.
-    try:
-        blob = base64.b64decode(b64str)
-    except TypeError:
-        raise ValueError("Invalid base64 text: %s" % b64str)
+def _b64dgz(data):
+    """Decode a string base64 encoding, if gzipped, uncompress as well
 
-    if not gzipped:
-        return blob
+    :return: decompressed unencoded string of the data or empty string on
+       unencoded data.
+    """
+    try:
+        blob = base64.b64decode(data)
+    except (TypeError, ValueError):
+        logging.error(
+            "Expected base64 encoded kernel commandline parameter"
+            " network-config. Ignoring network-config=%s.", data)
+        return ''
 
-    return _decomp_gzip(blob, strict=gzipped != "try")
+    return _decomp_gzip(blob)
 
 
 def read_kernel_cmdline_config(cmdline=None):
@@ -273,6 +271,8 @@ def read_kernel_cmdline_config(cmdline=None):
             if tok.startswith("network-config="):
                 data64 = tok.split("=", 1)[1]
         if data64:
+            if data64 == KERNEL_CMDLINE_NETWORK_CONFIG_DISABLED:
+                return {"config": "disabled"}
             return util.load_yaml(_b64dgz(data64))
 
     return None