M2Doc Get list of all items of a specific type, referenced in a diagram, including reference through a transfer node?

Question

I'm using the ISO21434 Best Practice template and I want to report details of all security:Attack nodes, but only those that are actually used in an attack tree which traces up to a threat scenario. I want to be able to do so even if the attack is referenced in an attack tree which traces to a threat scenario via a transfer node. For example:

Threat Scenario Node --child--> transfer node --child--> transfer node --child--> attack node

I can get a collection of all attack trees which have a threat scenario as the root node. From that I can get a list of attacks referenced _directly_ in that tree's diagram. I can also get a collection of transfer nodes in the diagram. However, I don't see how I could iterate down all transfer nodes to find other attacks.

I don't want to use a for loop as at the end I want a single collection of the attacks that I can sort on the attack ID before printing.

Is there a way to do this?

Thank you.

medini_1063298071 · Answer

Hi Nils,

I just happened to find the forum entry that mentioned it while searching for something else. The closure I'm doing is only over transfer gates, thus I don't think it would pick up an unconnected event/attack? My final macro to get "allUsedAttacks" does collect all of the events, but that is what I want.

Br,

Erik

medini_1059007410 · Answer

Hi Erik,

Oh, that's good news. I didn't know about the closure() service, it's not part of the current documentation, but  apparently that's outdated on that aspect (found this via web search). How did you find it, as it's only mentioned for OCL in this forum once?

The recursion of closure() is indeed what you need. If your concrete solution works for you, great. If I'm not mistaken (haven't thought it completely through), then your solution requires very diligent tree modelling, as you might pick up unconnected base events/attacks on the relevant diagrams as well. If that's not the case, then all ok. And all relevant attack tree top events have to be on a diagram, of course.

A bit more robust could be the recursion from top events just down the logical gates/intermediate events/transfer gates.

Anyway, the closure() service is a great addition for AQL :-)

Happy scripting,

Nils

medini_1063298071 · Answer

Hi Nils,

Thanks for the response. I found elsewhere on the forum a mention and link showing that the query language supports closures. I was able to use a closure to recursively build a collection of all the AttackTrees, starting from those with a root node representing a threat scenario. From that collection I could then extract all of the attacks in those trees. In case it helps someone else, here are the queries I'm using:

First I get all of the threat scenarios and all of the attack trees in the model/project: {m:let allProjectThreatScenarios = security::Threat.allInstances()->select(t | not (t.eAnnotations->exists(a | a.details.key->exists(k | k = 'UNECE Catalog'))))->asOrderedSet()->sortedBy(t | t.id)}

{m:let attackTrees = projectmodel::PJDiagram.allInstances()->select(diagram | diagram.canvasElement.oclIsKindOf(attacktree::AttackTree))->collect(diagram | diagram.canvasElement.oclAsType(attacktree::AttackTree))}

(I haven't tested it, but I can probably more directly get attackTrees by using attackTree::AttackTree.allInstances())

Then I use an intersection to limit the collection of attack trees to only those with a root node representing a threat scenario:

{m:let attackTreesForProjectThreats = attackTrees->select(at | allProjectThreatScenarios->intersection(at.rootNodes->collect(r | r.represents))->notEmpty())}

Then I use a closure to walk through all transfer gates to get the attack tree referenced by the transfer gate. I'll be assuming that the transfer gate is transferring to a node at the root of an attack tree.

{m:let allUsedAttackTrees = attackTreesForProjectThreats->closure(at | at.gates->select(g | g.oclIsKindOf(FTA::TransferGate))->collect(tg | tg.targetEventNode.model))->asOrderedSet() }

And then, finally, I extract the attacks out of the attack trees.

{m:let allUsedAttacks = allUsedAttackTrees->collect(at | at.eventNodes)->select(a | a.represents <> null and a.represents.oclIsKindOf(security::Attack))->collect(a | a.represents.oclAsType(security::Attack))->asOrderedSet()->sortedBy(a | a.id)}

I may consider improving this to do the closure directly over the children property to support transfer gates transferring to a non-root node. But this is working for my current use case.

Best regards,

Erik