• Finds paths to a given code block inside a function
• Finds paths between two or more functions
• Generates interactive call graphs
• Fully scriptable

In IDA's UI, navigate to View->Graphs->Find paths from the current function to...; this will search for call paths from the function your cursor is currently in to one or more destination functions.

Select a function from the function chooser dialog and click OK.

You will be prompted again to choose another function; you may continue this process to select as many destination functions as you'd like. Once you are finished, click Cancel or press the Esc button.

The call graph is interactive; double-clicking on a graph node will jump to that location in IDA's disassembly window. You may also dynamically change which nodes are displayed at any time using the following hotkeys:

• To only show paths that traverse a particular node: right-click the graph, select Include node, and then click on the node.
• To exclude all paths that traverse a particular node: right-click the graph, select Exclude node and then click on the node.
• To undo any of the above actions: right-click the graph, and select Undo.
• To redo an undo: right-click the graph, and select Redo.
• To reset the graph: right-click the graph, and select Reset graph.

For practical purposes, there is a maximum depth limit imposed on path searches. You can increase or decrease this limit in the IDAPython terminal:

Python> print ALLEYCAT_LIMIT
10000
Python> ALLEYCAT_LIMIT = 2500

To generate a list of unique paths between two functions, use the AlleyCatFunctionPaths class:

Python> print AlleyCatFunctionPaths(ScreenEA(), idc.LocByName('strcpy')).paths

To generate a list of unique paths from the between two code blocks inside a function, use the AlleyCatCodePaths class:

Python> print AlleyCatCodePaths(idaapi.get_func(idc.ScreenEA()).startEA, idc.ScreenEA()).paths

To create an interactive graph, use the AlleyCatGraph class:

Python> paths = AlleyCatFunctionPaths(ScreenEA(), idc.LocByName('strcpy')).paths
Python> graph = AlleyCatGraph(paths)
Python> graph.Show()

Just copy alleycat.py into your IDA plugins directory.