Microdroid Signature

Microdroid Signature contains the signatures of the payloads so that the payloads are verified inside the Guest OS.

• APEX packages that are passed to microdroid should be listed in the Microroid Signature.

Format

Microdroid Signature is composed of header and body.

How to Create

For testing purpose, use mk_microdroid_signature to create a Microdroid Signature.

$ cat signature_config.json
{
  "apexes": [
    {
      "name": "com.my.hello",
      "path": "hello.apex"
    }
  ]
}
$ adb push signature_config.json hello.apex /data/local/tmp/
$ adb shell 'cd /data/local/tmp; /apex/com.android.virt/bin/mk_microdroid_signature signature_config.json signature

Then, pass the signature as the first partition of the payload disk image.

$ cat payload_cdisk.json
{
  "partitions": [
    {
      "label": "signature",
      "path": "signature"
    },
    {
      "label": "com.my.hello",
      "path": "hello.apex"
    }
  ]
}
$ adb push payload_cdisk.json /data/local/tmp/
$ adb shell 'cd /data/local/tmp; /apex/com.android.virt/bin/mk_cdisk payload_cdisk.json payload.img
$ adb shell 'cd /data/local/tmp; /apex/com.android.virt/bin/crosvm .... --disk=payload.img'

In the future, VirtManager will handle these stuffs.