Fix OVF XML disk parsing (#25)

fox-it · Oct 6, 2023 · 0f04ac2 · 0f04ac2
1 parent ac6628c
commit 0f04ac2
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Showing 3 changed files with 183 additions and 5 deletions.
diff --git a/dissect/hypervisor/descriptor/ovf.py b/dissect/hypervisor/descriptor/ovf.py
@@ -1,4 +1,7 @@
-from xml.etree import ElementTree
+from typing import Iterator, TextIO
+from xml.etree.ElementTree import Element
+
+from defusedxml import ElementTree
 
 
 class OVF:
@@ -11,9 +14,9 @@ class OVF:
     DISK_XPATH = "ovf:DiskSection/ovf:Disk"
     DISK_DRIVE_XPATH = 'ovf:VirtualSystem/ovf:VirtualHardwareSection/ovf:Item/[rasd:ResourceType="17"]'
 
-    def __init__(self, fh):
+    def __init__(self, fh: TextIO):
         self.fh = fh
-        self.xml = ElementTree.fromstring(fh.read())
+        self.xml: Element = ElementTree.fromstring(fh.read())
 
         self.references = {}
         for file_ in self.xml.findall(self.FILE_XPATH, self.NS):
@@ -27,12 +30,18 @@ def __init__(self, fh):
             file_ref = disk.get("{{{ovf}}}fileRef".format(**self.NS))
             self._disks[disk_id] = self.references[file_ref]
 
-    def disks(self):
+    def disks(self) -> Iterator[str]:
         for disk in self.xml.findall(self.DISK_DRIVE_XPATH, self.NS):
             resource = disk.find("{{{rasd}}}HostResource".format(**self.NS))
-            _, _, xpath = resource.text.partition(":")
+            xpath = resource.text
+            if xpath.startswith("ovf:"):
+                xpath = xpath[4:]
+
             if xpath.startswith("/disk/"):
                 disk_ref = xpath.split("/")[-1]
                 yield self._disks[disk_ref]
+            elif xpath.startswith("/file/"):
+                file_ref = xpath.split("/")[-1]
+                yield self.references[file_ref]
             else:
                 raise NotImplementedError(resource)
diff --git a/pyproject.toml b/pyproject.toml
@@ -25,6 +25,7 @@ classifiers = [
   "Topic :: Utilities",
 ]
 dependencies = [
+    "defusedxml",
     "dissect.cstruct>=3.0.dev,<4.0.dev",
     "dissect.util>=3.0.dev,<4.0.dev",
 ]

diff --git a/tests/test_ovf.py b/tests/test_ovf.py
@@ -0,0 +1,168 @@
+from io import StringIO
+
+from dissect.hypervisor.descriptor.ovf import OVF
+
+# Handcrafted to include some test cases
+TEST_OVF = """<?xml version="1.0"?>
+<Envelope ovf:version="1.0" xml:lang="en-US" xmlns="http://schemas.dmtf.org/ovf/envelope/1" xmlns:ovf="http://schemas.dmtf.org/ovf/envelope/1" xmlns:rasd="http://schemas.dmtf.org/wbem/wscim/1/cim-schema/2/CIM_ResourceAllocationSettingData" xmlns:vssd="http://schemas.dmtf.org/wbem/wscim/1/cim-schema/2/CIM_VirtualSystemSettingData" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:vbox="http://www.virtualbox.org/ovf/machine">
+  <References>
+    <File ovf:id="file1" ovf:href="disk1.vmdk"/>
+    <File ovf:id="file2" ovf:href="disk2.vmdk"/>
+    <File ovf:id="file3" ovf:href="disk3.vmdk"/>
+  </References>
+  <DiskSection>
+    <Info>List of the virtual disks used in the package</Info>
+    <Disk ovf:capacity="1024" ovf:diskId="vmdisk1" ovf:fileRef="file1" ovf:format="http://www.vmware.com/interfaces/specifications/vmdk.html#streamOptimized" vbox:uuid="d3f38cfc-d512-425c-9ca8-5c046492a9a8"/>
+    <Disk ovf:capacity="1024" ovf:diskId="vmdisk2" ovf:fileRef="file2" ovf:format="http://www.vmware.com/interfaces/specifications/vmdk.html#streamOptimized" vbox:uuid="663d3136-5211-4d29-aacf-b4ef38be5fa2"/>
+  </DiskSection>
+  <NetworkSection>
+    <Info>Logical networks used in the package</Info>
+    <Network ovf:name="NAT">
+      <Description>Logical network used by this appliance.</Description>
+    </Network>
+  </NetworkSection>
+  <VirtualSystem ovf:id="Test OVF">
+    <Info>A virtual machine</Info>
+    <OperatingSystemSection ovf:id="100">
+      <Info>The kind of installed guest operating system</Info>
+      <Description>Linux26_64</Description>
+      <vbox:OSType ovf:required="false">Linux26_64</vbox:OSType>
+    </OperatingSystemSection>
+    <VirtualHardwareSection>
+      <Info>Virtual hardware requirements for a virtual machine</Info>
+      <System>
+        <vssd:ElementName>Virtual Hardware Family</vssd:ElementName>
+        <vssd:InstanceID>0</vssd:InstanceID>
+        <vssd:VirtualSystemIdentifier>Test OVF</vssd:VirtualSystemIdentifier>
+        <vssd:VirtualSystemType>virtualbox-2.2</vssd:VirtualSystemType>
+      </System>
+      <Item>
+        <rasd:Caption>1 virtual CPU</rasd:Caption>
+        <rasd:Description>Number of virtual CPUs</rasd:Description>
+        <rasd:ElementName>1 virtual CPU</rasd:ElementName>
+        <rasd:InstanceID>1</rasd:InstanceID>
+        <rasd:ResourceType>3</rasd:ResourceType>
+        <rasd:VirtualQuantity>1</rasd:VirtualQuantity>
+      </Item>
+      <Item>
+        <rasd:AllocationUnits>MegaBytes</rasd:AllocationUnits>
+        <rasd:Caption>1536 MB of memory</rasd:Caption>
+        <rasd:Description>Memory Size</rasd:Description>
+        <rasd:ElementName>1536 MB of memory</rasd:ElementName>
+        <rasd:InstanceID>2</rasd:InstanceID>
+        <rasd:ResourceType>4</rasd:ResourceType>
+        <rasd:VirtualQuantity>1536</rasd:VirtualQuantity>
+      </Item>
+      <Item>
+        <rasd:Address>0</rasd:Address>
+        <rasd:Caption>sataController0</rasd:Caption>
+        <rasd:Description>SATA Controller</rasd:Description>
+        <rasd:ElementName>sataController0</rasd:ElementName>
+        <rasd:InstanceID>3</rasd:InstanceID>
+        <rasd:ResourceSubType>AHCI</rasd:ResourceSubType>
+        <rasd:ResourceType>20</rasd:ResourceType>
+      </Item>
+      <Item>
+        <rasd:Address>0</rasd:Address>
+        <rasd:Caption>usb</rasd:Caption>
+        <rasd:Description>USB Controller</rasd:Description>
+        <rasd:ElementName>usb</rasd:ElementName>
+        <rasd:InstanceID>4</rasd:InstanceID>
+        <rasd:ResourceType>23</rasd:ResourceType>
+      </Item>
+      <Item>
+        <rasd:AddressOnParent>3</rasd:AddressOnParent>
+        <rasd:AutomaticAllocation>false</rasd:AutomaticAllocation>
+        <rasd:Caption>sound</rasd:Caption>
+        <rasd:Description>Sound Card</rasd:Description>
+        <rasd:ElementName>sound</rasd:ElementName>
+        <rasd:InstanceID>5</rasd:InstanceID>
+        <rasd:ResourceSubType>ensoniq1371</rasd:ResourceSubType>
+        <rasd:ResourceType>35</rasd:ResourceType>
+      </Item>
+      <Item>
+        <rasd:AddressOnParent>0</rasd:AddressOnParent>
+        <rasd:Caption>disk1</rasd:Caption>
+        <rasd:Description>Disk Image</rasd:Description>
+        <rasd:ElementName>disk1</rasd:ElementName>
+        <rasd:HostResource>/disk/vmdisk1</rasd:HostResource>
+        <rasd:InstanceID>6</rasd:InstanceID>
+        <rasd:Parent>3</rasd:Parent>
+        <rasd:ResourceType>17</rasd:ResourceType>
+      </Item>
+      <Item>
+        <rasd:AddressOnParent>1</rasd:AddressOnParent>
+        <rasd:Caption>disk2</rasd:Caption>
+        <rasd:Description>Disk Image</rasd:Description>
+        <rasd:ElementName>disk2</rasd:ElementName>
+        <rasd:HostResource>ovf:/disk/vmdisk2</rasd:HostResource>
+        <rasd:InstanceID>8</rasd:InstanceID>
+        <rasd:Parent>3</rasd:Parent>
+        <rasd:ResourceType>17</rasd:ResourceType>
+      </Item>
+      <Item>
+        <rasd:AddressOnParent>2</rasd:AddressOnParent>
+        <rasd:Caption>disk3</rasd:Caption>
+        <rasd:Description>Disk Image</rasd:Description>
+        <rasd:ElementName>disk3</rasd:ElementName>
+        <rasd:HostResource>ovf:/file/file3</rasd:HostResource>
+        <rasd:InstanceID>9</rasd:InstanceID>
+        <rasd:Parent>3</rasd:Parent>
+        <rasd:ResourceType>17</rasd:ResourceType>
+      </Item>
+      <Item>
+        <rasd:AutomaticAllocation>true</rasd:AutomaticAllocation>
+        <rasd:Caption>Ethernet adapter on 'NAT'</rasd:Caption>
+        <rasd:Connection>NAT</rasd:Connection>
+        <rasd:ElementName>Ethernet adapter on 'NAT'</rasd:ElementName>
+        <rasd:InstanceID>7</rasd:InstanceID>
+        <rasd:ResourceType>10</rasd:ResourceType>
+      </Item>
+    </VirtualHardwareSection>
+    <vbox:Machine ovf:required="false" version="1.19-linux" uuid="{68383d3a-9a23-4789-a580-4f0a79437fd6}" name="Test OVF" OSType="Linux26_64" snapshotFolder="Snapshots" lastStateChange="2023-09-20T12:15:55Z">
+      <ovf:Info>Complete VirtualBox machine configuration in VirtualBox format</ovf:Info>
+      <Hardware>
+        <CPU>
+          <PAE enabled="true"/>
+          <LongMode enabled="true"/>
+          <X2APIC enabled="true"/>
+          <HardwareVirtExLargePages enabled="true"/>
+        </CPU>
+        <Memory RAMSize="1536"/>
+        <HID Pointing="USBTablet"/>
+        <Display controller="VMSVGA" VRAMSize="32"/>
+        <BIOS>
+          <IOAPIC enabled="true"/>
+          <SmbiosUuidLittleEndian enabled="true"/>
+        </BIOS>
+        <USB>
+          <Controllers>
+            <Controller name="OHCI" type="OHCI"/>
+            <Controller name="EHCI" type="EHCI"/>
+          </Controllers>
+        </USB>
+        <Network>
+          <Adapter slot="0" enabled="true" MACAddress="FFFFFFFFFFFF" type="virtio">
+            <NAT/>
+          </Adapter>
+        </Network>
+        <AudioAdapter driver="ALSA" enabled="true" enabledOut="true"/>
+        <RTC localOrUTC="UTC"/>
+        <Clipboard/>
+        <StorageControllers>
+          <StorageController name="SATA" type="AHCI" PortCount="4" useHostIOCache="true" Bootable="true" IDE0MasterEmulationPort="0" IDE0SlaveEmulationPort="1" IDE1MasterEmulationPort="2" IDE1SlaveEmulationPort="3">
+            <AttachedDevice type="HardDisk" hotpluggable="false" port="0" device="0">
+              <Image uuid="{d3f38cfc-d512-425c-9ca8-5c046492a9a8}"/>
+            </AttachedDevice>
+          </StorageController>
+        </StorageControllers>
+      </Hardware>
+    </vbox:Machine>
+  </VirtualSystem>
+</Envelope>
+"""  # noqa
+
+
+def test_ovf():
+    ovf = OVF(StringIO(TEST_OVF))
+    assert list(ovf.disks()) == ["disk1.vmdk", "disk2.vmdk", "disk3.vmdk"]