The manifest (MANIFEST.MF) file of an archive library (.apl) contains information about the files packaged in the archive. Two of these attributes dictate the conditions and behavior associated with loading r-code from an archive. Depending on the settings, the application may or may not be able to load r-code. The attributes are:
  • Signature-Policy
  • Validation-Policy
These attributes, if set appropriately, enhance the security of the application by only allowing r-code in archive files which have been signed, to be loaded by the application.

Signature policy

The Signature-Policy attribute describes how r-code can be loaded. There are two possible settings:
  • Open— Indicates that the signed archive file can be loaded in the same session as non-signed files (standalone r-code or image file, procedure library (.pl), or unsigned archive file (.apl)).
  • Required— Indicates that the AVM only allows signed archive files to be loaded. Access to any standalone r-code, image file, .pl file or unsigned archive file is disallowed.

Validation policy

The Validation-Policy attribute describes what action to take if validation of a file in the archive fails. There are three possible settings:
  • None— The AVM continues with execution.
  • Warn— The AVM displays a warning message but continues with the execution.
    Note:
    • The AVM allows the session to suppress any type of warning messages (via startup parameters and SESSION attributes).
    • Warning messages are not caught by any CATCH blocks.
  • Fail—The AVM causes the operation to fail and raises a STOP condition.

For maximum security, set the Signature-Policy to Required and Validation-Policy to Fail.