xref_finder

xref_finder is a pair of tools that can be used for adding cross-references into an IDA Pro database that can't be identified using strictly static analysis, such as virtual calls (i.e. call eax). Using Pin to do the heavy lifting gives huge performance gains over a debugger. As a by-product of adding new cross-references, it's likely that IDA may auto-identify new functions as well. The idea was inspired byPortnoy's writeup on scripting the creation of xrefs using IDAPython (http://dvlabs.tippingpoint.com/blog/2012/02/23/adding-xrefs-via-idapy).

The first, xref_finder, is a Pin tool, which must be compiled and executed using Pin (http://www.pintool.org/). Running the desired executable with xref_finder will generate a log of caller to callee mappings.

The second, xref_parser, is an IDAPython plugin which parses this log, determines whether or not a particular mapping is eligible to be added as a cross-reference (valid address range, is not an existing cross-reference) and adds the cross-references accordingly. To highlight what new cross- references have been built, the script will add regular comments next to each "call" instruction.

This tool is intended to solve a very specific purpose, but Pin and IDAPython could be further utilized to do a lot more interesting things.

Pre-requisites

These tools are designed for use with IDA Pro. You'll also need IDAPython and Pin. For testing, I compiled the tool using Visual Studio 2010, but you shouldn't have [much of] a problem using some other compiler on some other operating system.

Building the Pin tool

Note: This Pin tool has only been tested on Windows, using Visual Studio 2010.

Move the xref_finder directory into the source/tools/ directory within your Pin directory. From a Visual Studio command prompt, change into the xref_finder directory and simply type nmake. By default, the resulting tool can be found within a new "obj-ia32" directory (on x86 architecture).

Running the Pin tool

Pin tools are essentially libraries, intended to be used with the Pin application. From your Pin directory, run something like the following.

pin -t path\to\xref_finder.dll -- calc.exe

In this example, "calc.exe" will launch and a file called xrefs_omg.out will be created in the directory from which Pin was run.

The tool doesn't account for child processes (yet?) so mileage may vary.

Running the IDAPython script

I suspect that this is self-explanatory. Suck in the output the xref_finder output (by default, xref_omg.out).

Quirks

There may be some. They may be more obvious to you than to me. Because I wrote this tool to actually use, I am interested in improving its functionality and reliability. There's a very good chance that you are a better Python and/or C++ programmer with a better understanding of how software works. Please be sure to share any suggestions, comments, or criticisms.