swift-frida

Swift runtime interop from Frida -- interact with iOS apps written in Swift, using Frida. (See frida-swift instead, if you're looking to script the Frida debugging session using Swift code you write.)

Status

The functionality described below is mostly stable and working, but probably still has some bugs that need to be fixed (please report them!).

I'm mainly testing things on iOS 11.1.2 (64bit), and on iOS 9.3.5 (32bit). Other operating systems are not supported for now. Only apps using Swift 4.0.* are supported at the moment.

Usage

Clone the project, and install its dependencies:

git clone https://github.com/maltek/swift-frida.git
cd swift-frida
npm install

In your script, add this line:

const Swift = require('/path/to/swift-frida/');

Afterwards, compile your script with frida-compile like this:

frida-compile -w -o /tmp/compiled.js your-script.js

To play around with the API interactively, you can load the compiled loader.js into the REPL:

$ frida-compile -w -o /tmp/swift.js loader.js
$ frida -U -n Foo -l /tmp/swift.js
     ____
    / _  |   Frida 12.2.14 - A world-class dynamic instrumentation toolkit
   | (_| |
    > _  |   Commands:
   /_/ |_|       help      -> Displays the help system
   . . . .       object?   -> Display information about 'object'
   . . . .       exit/quit -> Exit
   . . . .
   . . . .   More info at http://www.frida.re/docs/home/

[iOS Device::Foo]-> Swift.available
true

More Information

You can have a look at a video recording and slides of a presentation about this project at r2con 2018.

Available APIs

Right now, the following functions are available in the Swift namespace, when the script is loaded:

• available Allows you to check if the current process uses Swift. Don't use any of the other functions here if this property is false.

• isSwiftName(name) Takes a function/symbol name (like you can get from Module objects), and returns a boolean indicating whether it is a mangled Swift name or not.

• demangle(name) Takes a mangled Swift name (like you can get from Module objects), and returns a demangled, human-readable String for it.

• getMangled(name) The opposite of demangle(name). Right now, this only works for names that were previously returned by demangle(name).

• _api This is an object providing access to many low-level functions in the Swift runtime.

• _typeFromCanonical(metadata) This function allows you to create a Type constructor from a low-level Metadata*.

• makeFunctionType(args, returnType, flags) Creates a new Swift Type constructor for a function type. args should be an array with the types of each argument, flags is an optional object with doesThrow and/or convention properties.

• makeTupleType(labels, innerTypes) Creates a new Swift Type constructor for a tuple type. labels and innerTypes are arrays with the labels and types of the tuple elements. Use empty strings for unlabeled elements.

• enumerateTypesSync(module) Searches for types defined in module, or in all loaded modules if that parameter is undefined. Returns a Map storing information about all known Swift data types defined in the Swift program. The keys are the names of the data types (as strings), and the values are objects describing the type. These objects have a toString method returning the fully qualified name of the type, including generic bounds (if possible) and a string property kind that tells you which kind of type (e.g. "Class", "Struct") it is. The Type property returns a Type constructor for the meta type of the represented type. Depending on the kind of type, additional methods are available:

  Kind	available method
  Enum	enumCases returns an array with all defined cases, with their names, types, and attributes.
  Class, Struct	fields returns an array with all fields of this class or struct, with names, offsets, types, and attributes.
  Tuple	tupleElements returns an array with the types and labels of the elements in the tuple.
  Function	returnType returns the return type of the function.
  Function	functionFlags returns an object telling you the calling convention and whether the function throws or not.
  Function	getArguments returns an array with the type and flags (inout) for every function argument.
  ObjCClassWrapper	getObjCObject returns an ObjC.Object describing this class.

  Uninstantiated generic types (you can check this with the isGeneric method), do not have any of these methods available. You must call withGenericParams to get a fully concrete type.

  For fully instantiated generic types or non-generic types, you can use these type objects as constructors -- you provide a pointer where a value of that type is stored, and get back an object that lets you interact with this variable. Note that this object only stays valid for as long as this pointer is valid and is not modified (except using methods directly on this object). Depending on the kind of type, the following properties exist:

  Kind	available property
  *	toString() returns a string with the debug representation of this variable
  *	$pointer the pointer where this value resides in memory
  *	$type the dynamic type of this value
  *	$staticType the static type of this value
  *	$destroy() destroys an owned Swift value. (On a best-effort basis this also happens when the object is garbage-collected.)
  *	$assignWithCopy(other) assigns a copy of other to this variable. other must have a compatible type (this is not checked).
  *	allocCopy() creates and returns an owned copy of this value. Use $destroy() on the return value when you are done using it!
  Function	The object is a function that you can call. (Other properties are still available.)
  ObjCClassWrapper	The object is an ObjC.Object. See the documentation there. (None of the properties for Swift values are available.)
  Class, Existential	$isa the isa pointer. (Only for Existential types when they are class bound.)
  Class, Existential	$retainCounts the number of references to this value. (Only for Existential types when they are class bound.)
  Enum	$enumCase' the index of the active case of this enum, see $type.enumCases`.
  Enum	$enumPayloadCopy() creates and returns an owned copy of the payload of this enum, or returns undefined if the active case has no payload. Use $destroy() on the return value when you are done using it!
  Class, Struct	Getters and setters for every field (see $type.fields()). When the field name collides with a property that exists on every JS object, or starts with a $, use $$ as a name to access such a field.
  Existential	$value allows you to get/set the value in this variable. (Only for Existential types when they are not class bound.)
  Tuple	Getters and setters for every tuple element (see $type.tupleElements(), by index or (when available) by label.

  Returned values are normally the same kind of SwiftValue objects, except for integers and booleans, which are transparently converted into their JavaScript equivalents. For strings, you can use toString() and $assignWithCopy to convert between the JavaScript and Swift types.

But, again, this is completely unstable and might change at any time.

License

Code in metadata.js is based on Apache-2.0 licensed Swift compiler source code. Code in runtime-api.js is based on wxWindows-3.1 licensed frida-objc source code.

The compatible intersection of those licenses is LGPL-3.0 (or later) with wxWindows exceptions. So that's also the license terms under which we release the original code in this repository.