how to encrypt and sign iphone mobile configuration file using Ruby

Question

I have a unsigned mobileconfig file in xml format (template) generated by iphone configuration utility. I would like to encrypt and sign it using openssl and be able to inst

Answer 1

Incase if still anybody is having issues with signing and encrypting the profile with Ruby, following answer would be useful.

I have used OpenSSL module available in Ruby and Plist gem.

Consider a passcode restriction profile.

passcode_payload ={
              'PayloadUUID' => 'RANDOM_STRING_UUID',
              'PayloadOrganization' => 'PayloadOrganization',
              'PayloadVersion' => 1,
              'PayloadIdentifier' => 'com.test.PayloadIdentifier',
              'PayloadType' => 'Configuration',
              'PayloadDisplayName' => 'PayloadDisplayName',
              'PayloadRemovalDisallowed' => false
            }
  passcode_payload_content = {
              'PayloadDescription' => 'PayloadDescription',
              'PayloadDisplayName' => 'PayloadDisplayName',
              'PayloadIdentifier' => 'PayloadIdentifier',
              'PayloadOrganization' => 'PayloadOrganization',
              'PayloadType' => 'com.apple.mobiledevice.passwordpolicy',
              'PayloadUUID' => "RANDOM_STRING_UUID",
              'PayloadVersion' => 1,
              'allowSimple' => true,
              'forcePIN' => true
              'maxPINAgeInDays' => 20,
              'minComplexChars' => 1,
              'minLength' => 4,
              'requireAlphanumeric' => true
            }

**

Encryption

**

Usually for a normal profile the passcode_payload_content goes into the passcode_payload['PayloadContent'] as array of dictionaries.

passcode_payload['PayloadContent'] = [passcode_payload_content]

But for an encrypted profile, PayloadContent should be removed and EncryptedPayloadContent should be used as per the configuration profile key reference document.

from the doc,

To encrypt a profile do the following:

Remove the PayloadContent array and serialize it as a proper plist.

Note that the top-level object in this plist is an array, not a dictionary.

CMS-encrypt the serialized plist as enveloped data. Serialize the encrypted data in DER format.

Set the serialized data as the value of as a Data plist item in the profile, using the key EncryptedPayloadContent

Since top level object in the plist should be an array

passcode_payload_content_array = [passcode_payload_content]

Serializing to proper plist

to_be_encrypted_plist = passcode_payload_content_array.to_plist

Encrypting the certificate payload content,

device_certificate = OpenSSL::X509::Certificate.new File.read('deviceIdentityCertificate.pem')
encrypted_payload = OpenSSL::PKCS7.encrypt([device_certificate],to_be_encrypted_plist, OpenSSL::Cipher::Cipher::new("des-ede3-cbc"),OpenSSL::PKCS7::BINARY)

Add encrypted payload content to the original payload in der format

passcode_payload['EncryptedPayloadContent'] = StringIO.new(encrypted_payload.to_der)

**

Signing

**

signed_passcode_profile = OpenSSL::PKCS7.sign(SSL_CERTIFICATE, SSL_KEY, passcode_payload.to_plist, [], OpenSSL::PKCS7::BINARY)

At last, you can use

send_data signed_passcode_profile.to_der, :type => "application/x-apple-aspen-config" 

to send the payload.