BRF+ rules are nice for developers to use, but can give you some serious issues at transport level.
Questions that will be answered in this blog are:
Which tools and analysis programs are available in case I have issues with BRF+ transports?
How to recognize BRF+ transport issues?
Which relevant OSS notes to check in case of transport issues?
BRF+ transport issue detection
BRF+ rules can cause both issues at export (RC-8) and at import (RC-8 or content not updated while transport shows RC-0 or RC-4). Check the transport for BRF+ rules: they start with FDT.
Troubleshooting BRF+ with FDT_HELPERS
The main basis troubleshooting transaction is FDT_HELPERS.
It contains many tools that can assist in issue solving.
The exit is also used a lot by GRC and firefighter type of tools.
The user exit logon hack
In the user exit code, you can put in your own stuff.
As hacking example: copy function module PASSWORDCHECK and the screen that belongs to it to your own ZPASSWORDCHECK.
Modify the screen logic a bit. This is the original code:
Now change the code: the password is always reported back as ok. And the user input you catch in the field password is yours: you can mail it or store it somewhere for you to pick up later.
Put the altered code in the user-exit with logic:
IF SY-UNAME = 'target user name' and not capture before.
CALL Z function ZPASSWORDCHECK.
Store capturing.
Set capture flag.
ENDIF.
This looks as follows at runtime:
Many end users (and even auditors) will enter their password without thinking twice.
Alternatively you can use function module POPUP_GET_USER_PASSWORD as a basis for your copy: this has also clear text password:
The password field can be stored.
This has the following look and feel:
Detection and protection
It is wise to shield off this user exit from improper use and to yearly check the content of what is inside this user exit.
The ABAP push channel (APC) is the ABAP implementation of websockets. It’s goal is to enable the ABAP stack to send push messages to registered web clients.
This blog will answer the following questions:
How to setup an ABAP push channel?
How to implement the ABAP push channel?
How to test the ABAP push channel?
Where to find more background and examples on ABAP push channel?
Setting up an ABAP push channel
To setup an ABAP push channel go to transaction SE80 and right click, select create / connectivity / ABAP push channel notification.
Now press the Generate Class and Service button. The classes and services will now be generated as placeholders. Save your work.
If you try to activate the service at this point in time you get this error message:
The reason is that we didn’t implement two methods of the new class yet: the ON_START and ON_MESSAGE.
Implementing the actual APC class
To do this, we go to SE24 and lookup the generated class and we select the ON_START method:
Press the redefine button to redefine the method.
Use this code in the method:
TRY.
* send the message on WebSocket connection
DATA(lo_message) = i_message_manager->create_message( ). lo_message->set_text( |ON_START has been successfully executed !| ).
i_message_manager->send( lo_message ).
CATCH cx_apc_error INTO DATA(lx_apc_error).
MESSAGE lx_apc_error->get_text( ) TYPE 'E'.
ENDTRY.
This basically confirms the push channel registration.
Now redefine the ON_MESSAGE method:
TRY.
* create the message object
DATA(lo_message) = i_message_manager->create_message( ).
* send message
lo_message->set_text( |Hello World !| ).
i_message_manager->send( lo_message ).
CATCH cx_apc_error INTO DATA(lx_apc_error).
MESSAGE lx_apc_error->get_text( ) TYPE 'E'.
ENDTRY.
It simply pushes the message: ‘Hello World’.
Save and generate the class in SE24.
Now we can go back to the SE80 ABAP push channel we have created and activate it as well. You can run the consistency check to see all is fine:
Testing the ABAP push channel
Now you can test the ABAP push channel by hitting the test button in the SE80 screen of the ABAP push channel. The test service will launch an ABAP webdynpro screen.
If the ABAP webdynpro screen does not launch, activate in SCIF transaction the following 2 nodes: WDR_TEST_APC and WDR_TEST_APC_WSP.
Test result:
As an alternative to SE80 you can also use transaction SAPC:
The SAP ABAP stack can also interface using REST protocol. To support this interface protocol SAP has developed special classes in the ABAP stack.
Questions that will be answered in this blog are:
How do I create a REST interface in ABAP stack?
How do I test a REST interface in ABAP stack?
Which tools to use to developer REST interface?
REST in ABAP
SAP delivers in the ABAP netweaver stack the ABAP REST library. The full specification can be found on the SAP help portal. The help portal also contains a small tutorial. Next to the pre-delivered REST library classes there are no tools for you available to faster develop REST in ABAP. It is coming down to SE24 and SE80.
We will create a simple Hello World REST service in ABAP. There are 2 main classes in REST ABAP: the application class handling the URL and the resource class where the logic is.
Start transaction SE24 and create a new class inheriting from the SAP delivered class CL_REST_HTTP_HANDLER:
important here to press the inheritance button! Fill out CL_REST_HTTP_HANDLER as superclass:
It is mandatory to redefine the GET_ROOT_HANDLER method:
For now just leave the method empty. Save and generate.
Now create the REST resource class based on inheritance of CL_REST_RESOURCE:
Now redefine the GET method:
No we add a simple implementation by simply adding the text ‘Hello World’:
Save and activate this class.
Now we go back to the previous class: the application class. In here we now edit the GET_ROOT_HANDLER implementation we left empty earlier:
If the URL is getting the input /hello then the handler class (our resource class) ZCL_HELLO_WORLD_RES_REST is called. This class will return the string.
Save and activate again. The coding work is done.
Runtime implementation
Now we need to make a runtime implementation. Goto transaction SICF and select the main node default_host first. Then select from the menu Service/Host the option Create Service:
Fill out the name of the service and click ok. In the next screen give a description and in the Handler List section refer to the application class ZCL_HELLO_WORLD_REST:
Save the service. The service is created but not active. To activate right click on the service and select Activate:
Testing the service
From the previous SICF screen right click the service again and select the option Test Service. A screen will come that says “No suitable resource found”. Now modify the URL by adding /hello after the test in the URL, and press enter again:
The URL build up: the test is the name defined in SICF. The /hello was defined in the application class.
Authorizations and security
The REST library has no specifics about authorization and security. So you have to take care your self.
Business authorization security: has to be built in via AUTHORITY-CHECK statements at the correct spots.
Technical security is provided in the Logon Data tab on the SICF node. Here you can set requirements for the technical logon method and if you only allow https.
In the previous blog we have setup RFC enabled function module. If you want to expose this function module as ODATA service you can use the wizard in transaction SEGW. This blog assumes the basis ODATA basis activation has been performed (see this blog).
Questions that will be answered in this blog are:
How do I generate an ODATA service based on a RFC function module?
How do I test if the ODATA service is properly working?
Set up of the ODATA service
Start transaction SEGW and create a new project:
Now start the RFC import wizard by right clicking on Data Model and selecting the option Import and then RFC/BOR interface:
Now select the data parameters:
And enter which field is key field:
After pressing finish the wizard will generate the needed classes.
Save your work and press the check button to validate if everything is ok:
Now we need to map the implementation to the RFC module. Right click on the GetEntitySet below ZODATADEMOENTITYSet and select Map to Data Source:
Now map the fields (you can use drag and drop):
Now you need to map the data fields correctly and press check.
Save your work.
Generation of objects
You can see that the Runtime Artifacts section is still empty.
Now press the button Generate Runtime Artifacts:
Wait for the generation to finish:
Now the runtime artifacts are generated, but the service maintenance is not done yet. Open the section Service maintenance and double click on the system:
Now press the Register Service button:
Accept settings and assign package for transport:
Now the registration status is green.
Testing the ODATA service
Press the button SAP Gateway Client (or start transaction /IWFND/GW_CLIENT directly, and then enter the correct service):
The test client starts:
Enter the correct inputdata: /sap/opu/odata/SAP/ZODATADEMO_SRV/ZODATADEMOENTITYSet(‘1’)
And check the output:
Attention points
The example above seems simple, but you will face more issues in real live implementation when you need to add tables and more complex structures. In those cases additional configuration and many times extra coding in the methods of the generated classes is required.
The user calling the ODATA service needs a special right in SAP to be allowed to call the ODATA service.
Start transaction PFCG and create a new role. On the menu tab select the option Authorization Default. Then select type Tadir and object type IWSV gateway business suite enablement. Now you can finally search for our own developed and activated ODATA service:
Now save the role and assign it to the user(s) needing to call this ODATA service.
The application security relies on the function security authorization check inside the RFC function module.
In the previous blog we have created a test RFC module. We now will expose this test RFC module as web service. This blog assumes the basic SOAP web service runtime has been done according to the manual in this blog.
Questions that will be answered are:
How can I generate a web service design time based on an RFC module?
How do I activate the web service runtime via SOAMANAGER?
How do I test my web service?
Creating the web service based on RFC module
Goto transaction SE80 and search for the test BAPI:
Now right click on the name ZBAPIDEMO function module and select the option Create / Enterprise Service:
Fill out the name for the service definition and the description. Press Cont. to continue to the next screen:
Press Cont to go to the next step:
Press Cont. to go to the next screen:
Fill out your package and transport request.
Important here: on a sandbox you might want to use a local object ($TMP). In a development system, NEVER use the local option. A lot of data structures and coding will be generated. If you later try to move the objects from $TMP to a real package, you will be faced with a lot of issues. See note 886682 - Proxy inconsistencies on the use of repair programs SXIVERI_PROXY_HASHID_CHECK and SXIVERI_PROXY_HASHID_CHECK_70. After the cumbersome and painfull repair you will not make the mistake again...
Press Cont. to goto the last screen:
On the screen you can already see the next action after completion: SOAMANAGER. But first press Complete to start the generation of the objects.
After the generation, do not forget to Activate the objects!
Activation success message:
Setting up the runtime with SOAMANAGER
To setup the runtime, start transaction SOAMANAGER. It is assumed that the basis team has performed the initial SOAP runtime setup. If not done, ask the basis team to follow the steps in this blog.
On the SOAMANAGER start screen choose the option Web Service Configuration:
In the next screen search for the design time object we created and activated in the previous section (if you forgot the activate, you will not find it now…):
Select the service and on the next screen press the button Create Service:
Fill out the definition details:
Press Next and define the security settings:
Remark: in the newer versions, the default security is set to high. If you need lower security, go back to SE80 definition in the tab configuration to change the security profile (save and regenerate!):
Press next and define the SOAP protocol settings:
On the last screen of the wizard press finish:
Wait for the runtime generation to finish.
The screen returns to the generated runtime artefacts:
The most important artefact is WSDL file which you can open from here.
Testing the service
Goto transaction SE80 and select the Enterprise Services Browser (if not visible goto menu path Utilities/Settings and add the tool):
Now open your service by clicking the Open Object button and search for the service in the second tab:
Check that the WSDL file is properly showing:
If ok, press the test button (F8) to start the test tool:
On the next screen first press the XML editor button to allow the content to be changed:
Now press execute to test. The result:
Web service security
The functionality security of the web service is the same as for the generic RFC handling (see blog on this).
The technical security of web services is mainly driven from the security settings in SOAMANAGER. There you can set the transport protocol security and you can indicate if you want simple user ID / password security or work with additional certificates for server to server authentication.
The user calling the SAP web service must have the authorization object S_SERVICE. In S_SERVICE you can define the specific web service it needs to be able to call.
SAP has many different ways to interface. The RFC (Remote Function Call) protocol is one of the most wide used.
This blog will explain best practices around secure and correct setup of custom built ABAP RFC function modules.
Questions that will be answered are:
How to setup RFC enabled function module?
How to setup proper RFC error handling?
How to setup security in RFC enabled function module?
How strict is the S_RFC authorization handling?
Why is SAP_ALL not sufficient for RFC handling?
Creation of test RFC enabled function module
In SE37 you can setup an RFC enabled function module just like a normal function module. First create a function group. Activate that function group in SE80. Now you can create the function module. We will call our test module ZBAPIDEMO:
Important here in the first tab is to set the processing type to Remote-Enabled Module.
For testing we setup import and export tabs:
Important here with RFC: set the Pass by value tickbox.
For tables use a suitable table type:
And setup the correct exceptions:
Here you can see 2 very important error messages that should always be implemented:
An extra authorization check
An error message when no data is found
Now we can implement the following simple source code:
DATA: zls_coms_gen_textline TYPE coms_gen_textline.
AUTHORITY-CHECK OBJECT 'S_CDMC'
ID 'CDMC_AREA' FIELD 'A'
ID 'CDMC_ROLE' FIELD 'U'.
IF sy-subrc EQ 0.
CASE zimport.
WHEN 1.
zexport = 'Hello world'.
WHEN 2.
zls_coms_gen_textline-entry = 'Hello world table 1'.
APPEND zls_coms_gen_textline TO ztable.
zls_coms_gen_textline-entry = 'Hello world table 2'.
APPEND zls_coms_gen_textline TO ztable.
WHEN OTHERS.
RAISE not_found.
ENDCASE.
ELSE.
RAISE not_authorized_business.
ENDIF.
What is important here in this source code:
The authorization check is implemented and raises an error
If no data is found the NOT_FOUND error is raised
With the SE37 test suite you can test diverse scenario’s now.
Calling RFC function module from another ABAP system
If you call this RFC function module form another ABAP sytem you have to make sure you have set and check the following exceptions:
COMMUNICATION_FAILURE: the call to the other system fails. Most likely if you go to SM59 to the RFC destination and perform a connection test you will get a failure.
OTHERS: something else went wrong
The developer should take proper care of these error situations.
Dear ABAP developers: the basis team member are also humans. They will make RFC configuration errors, they rely on the authorization team to assign the correct roles and they rely on infrastructure providers to make sure systems are up and running. Also the basis team will need to perform patching and upgrades to the system, which you as ABAP developer, are calling. So please don't blame the basis team for these exceptions, but please be a good developer and implement proper error handling. If you didn't implement proper error handling, and something went wrong on basis side, that caused your code to go wrong, think twice before putting blame on basis if your code is not handling the situation properly.
The RFC layer is protected by authorization object S_RFC:
Here you can choose between a function group or even allowing per function module. Personally I would protect by function module. Background: create, change and display BAPI’s will normally be developed inside same function group.
There is a common misunderstanding that if you give SAP_ALL to a (background) user, this would solve the RFC authorization issues. This is not true. SAP_ALL does not contain the S_RFC rights. You have to hand them out separately.
Best practice 1: you might want to start with broad authorizations at the beginning of a development to rule out authorization issues. But you must definitely limit the rights before you make the development go productively live.
Best practice 2: as first statement inside each and every RFC function module, program a relevant business authorization check statement. This is an extra safety measure that is needed to protect important business data from authorization consultants that have handed out * authorizations in object S_RFC (* means all).
More on checking the basis RFC security: read this blog.
Generic S_RFC check handling at basis level
The behavior of the S_RFC check is driven by the settings of RZ11 profile parameter auth/rfc_authorithy_check. Please make sure it has a setting of 6 or higher. Best is 9. A system with 5 or lower can be considered as insecure!
SCI is a very powerful code scanning tool (see blog). Unfortunately you cannot apply it to standard SAP and add-ons.
Analyzing standard SAP code is the responsibility of SAP, and they take good and secure code (since they provide good code, it is weird they don’t allow everybody to scan their code…). Unfortunately a lot of add-on providers do not.
The blog will explain how to scan code of standard SAP and mainly on add-ons.
Questions that will be answered are:
What is the background on not being able to scan standard SAP and add-on code?
Can I truly scan the code of a new OSS note 7 days?
How can I work around these restrictions and still scan the code of an add-on?
Background
The background of not being able to scan standard SAP code is explained in OSS note 1986391 – Using SLIN/SCI to check SAP standard objects. This note also explains you can scan OSS notes and transports for 7 days. After that time it is no longer possible. Unfortunately this rule also applies to add-ons.
Why run SCI on add-ons?
Why would you want to scan add-ons? Add-ons come with various quality levels. Ranging from very well written with much attention to performance and security. Some add-ons are full of performance issues and full of security leaks. Some are even allowing full dynamic read SELECT and UPDATE statement without any authorization check. This is heaven for a hacker!
The below method is meant for scanning these poor add-ons using the SCI tool for performance, robust coding and security.
How to run SCI on add-ons?
When you run the SCI tool on an add-on by selecting package or development object, you get the message that it does not contain any objects:
This is because your selection is first scanned for standard SAP and add-on objects. These are removed. So the result set is empty.
Goto transaction SE24 and select class CL_CI_OBJECTSET. Now select method BUILD_TADIRSET and display the code:
Put a break-point as statement if ENABLE_CI ne ‘X’.
Now start the SCI tool again. If the debugger stops at this statement, use debug and replace to change the content of ENABLE_CI to ‘X’. Now the skipping of SAP and add-on objects is not done. SCI will scan the code. It will still not use SLIN. But these are minor checks.
