Overview of CDSA Programming on OpenVMS

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HP Open Source Security for OpenVMS Volume 1:...

CDSA Programming Concepts

Writing Signed Applications

Overview of CDSA Programming on OpenVMS

CDSA programming on OpenVMS works much the same as on any other platform. The following sections indicate differences and important information.

Compiling a CDSA Program

CDSA V2.0 was built using Compaq C V6.5-001. HP recommends that applications or add-in modules be developed using the same compiler to avoid problems that could occur if the run-time library changes in another version.

When you compile your program, you need to add the /INCLUDE=CDSA_SYSDIR:[INCLUDES] qualifier to your compiler command line. The following command is taken from the BUILD_DES.COM example in this chapter (see DES Encryption/Decryption Example Program):

$ CC/LIST/INCLUDE=CDSA_SYSDIR:[INCLUDES]/PREFIX=ALL DO_DES

Linking a CDSA Program

Most CDSA applications must link with SYS$SHARE:CDSA$INCSSM300_SHR.EXE. If the application uses MDS, you might need to include SYS$SHARE:CDSA$MDS300_SHR.EXE and SYS$SHARE:CDSA$MDS_UTIL_API.OLB as well.

Because CDSA routines are located in shareable libraries, the use of a link options file is recommended. For details about using link options files, refer to the OpenVMS Linker Utility Manual . The CDSA example programs described in CDSA Example Programs provide examples of using link options files for CDSA applications.

CDSA Integrity Checking

CDSA provides two types of integrity checking: bilateral authentication and pointer validation checking.

Bilateral Authentication

Bilateral authentication checks the integrity of modules as they are dynamically loaded into the system. A bilateral authentication procedure is designed for two entities to establish trust in the identity and integrity of each other. When loading a service provider module or an elective module manager, CDSA requires that the attaching module participate in this authentication protocol. Both modules in the bilateral authentication procedure must have signed credentials that bind them to the trust hierarchy used by CDSA. These credentials are stored in the CDSA MDS database during module installation.

Refer to the Intel Common Data Security Architecture Application Developer's Guide (Chapter 11, Integrity) and the Intel Common Data Security Architecture Manifest Signing Tools User's Guide for more detailed explanations of the bilateral authentication process.

Pointer Validation Checking

Pointer validation checking (PVC) entails validating addresses under the following circumstances:

Before calling across the application interface into CDSA (PVC is optional on OpenVMS in this case.)

Before calling across the CDSA interface to an add-in module (PVC is required on OpenVMS in this case.)

The Pointer Validation Policy is established using the PvcPolicy parameter in the CSSM_Init call. The parameter values can be derived using the constants in the file CSSMTYPE.H in CDSA_SYSDIR:[INCLUDES]. Starting with OpenVMS Alpha Version 7.3-2, the values for the PvcPolicy parameter that are valid for CDSA are as described in the following table.

Value Description

2
PVC validation is performed on service provider modules only. CSSM_PVC_SP is used for PVC validation on service provider modules.

3
PVC validation is performed on both service provider and application modules. The bitwise OR of CSSM_PVC_APP and CSSM_PVC_SP is used for PVC validation on both service provider and application modules; for example, (CSSM_PVC_APP | CSSM_PVC_SP).

Value	Description
2	PVC validation is performed on service provider modules only. CSSM_PVC_SP is used for PVC validation on service provider modules.
3	PVC validation is performed on both service provider and application modules. The bitwise OR of CSSM_PVC_APP and CSSM_PVC_SP is used for PVC validation on both service provider and application modules; for example, (CSSM_PVC_APP \| CSSM_PVC_SP).

For more information about pointer validation checking, see the description of the CSSM_Init() API.

Writing Signed Applications