fix(dhcpcd): Make lease parsing more robust (#5129)

canonical · Apr 3, 2024 · b0c7936 · b0c7936
1 parent 3d4213f
commit b0c7936
Show file tree

Hide file tree

Showing 2 changed files with 68 additions and 7 deletions.
diff --git a/cloudinit/net/dhcp.py b/cloudinit/net/dhcp.py
@@ -791,12 +791,20 @@ def parse_dhcpcd_lease(lease_dump: str, interface: str) -> Dict:
         try:
             lease = dict(
                 [
-                    a.split("=")
+                    a.split("=", maxsplit=1)
                     for a in lease_dump.strip().replace("'", "").split("\n")
+                    if "=" in a
                 ]
             )
+            if not lease:
+                msg = (
+                    "No valid DHCP lease configuration "
+                    "found in dhcpcd lease: %r"
+                )
+                LOG.error(msg, lease_dump)
+                raise InvalidDHCPLeaseFileError(msg % lease_dump)
         except ValueError as error:
-            LOG.error("Error parsing dhcpcd lease: %r", error)
+            LOG.error("Error parsing dhcpcd lease: %r", lease_dump)
             raise InvalidDHCPLeaseFileError from error
 
         # this is expected by cloud-init's code

diff --git a/tests/unittests/net/test_dhcp.py b/tests/unittests/net/test_dhcp.py
@@ -1199,17 +1199,70 @@ def test_parse_lease_dump(self):
         assert "255.255.240.0" == parsed_lease["subnet-mask"]
         assert "192.168.0.1" == parsed_lease["routers"]
 
+    @pytest.mark.parametrize(
+        "lease, parsed",
+        (
+            pytest.param(
+                """
+
+                domain_name='us-east-2.compute.internal'
+
+                domain_name_servers='192.168.0.2'
+
+                """,
+                {
+                    "domain_name": "us-east-2.compute.internal",
+                    "domain_name_servers": "192.168.0.2",
+                },
+                id="lease_has_empty_lines",
+            ),
+            pytest.param(
+                """
+                domain_name='us-east-2.compute.internal'
+                not-a-kv-pair
+                domain_name_servers='192.168.0.2'
+                """,
+                {
+                    "domain_name": "us-east-2.compute.internal",
+                    "domain_name_servers": "192.168.0.2",
+                },
+                id="lease_has_values_that_arent_key_value_pairs",
+            ),
+            pytest.param(
+                """
+                domain_name='us-east=2.compute.internal'
+                """,
+                {
+                    "domain_name": "us-east=2.compute.internal",
+                },
+                id="lease_has_kv_pair_including_equals_sign_in_value",
+            ),
+        ),
+    )
+    def test_parse_lease_dump_resilience(self, lease, parsed):
+        with mock.patch("cloudinit.net.dhcp.util.load_binary_file"):
+            Dhcpcd.parse_dhcpcd_lease(dedent(lease), "eth0")
+
     def test_parse_lease_dump_fails(self):
-        lease = dedent(
-            """
-            fail
-            """
-        )
+        def _raise():
+            raise ValueError()
+
+        lease = mock.Mock()
+        lease.strip = _raise
 
         with pytest.raises(InvalidDHCPLeaseFileError):
             with mock.patch("cloudinit.net.dhcp.util.load_binary_file"):
                 Dhcpcd.parse_dhcpcd_lease(lease, "eth0")
 
+        with pytest.raises(InvalidDHCPLeaseFileError):
+            with mock.patch("cloudinit.net.dhcp.util.load_binary_file"):
+                lease = dedent(
+                    """
+                    fail
+                    """
+                )
+                Dhcpcd.parse_dhcpcd_lease(lease, "eth0")
+
     @pytest.mark.parametrize(
         "lease_file, option_245",
         (