Generate Frida hooks based on c header files using pyclibrary

frida-hook-generator.py

from pyclibrary import CParser
import re


hook_template = '''
(function() {
	var name = '__NAME__';
	var address = Module.findExportByName(null, name);
	if (address != null) {
		console.log('[!] Hooking: ' + name + ' @ 0x' + address.toString(16));
		try {
			Interceptor.attach(address, {
				onEnter: function(args) {
					this.args = [];
					__ENTERARGS__
				},
				onLeave: function(result) {
					__LEAVELOG__
				},
			});
		}
		catch (error) {
			console.error(error);
		}
	}
})();
'''

def generate_hooks(header, pattern=None):
	output = []
	cparser = CParser(header, cache='/tmp/cparser.{0}.cache'.format(header.replace('/', '_')))
	functions = cparser.defs['functions']
	for function in functions.keys():
		if (pattern and re.match(pattern, function, re.IGNORECASE)) or not pattern:
			hook = hook_template
			hook = hook.replace('__NAME__', function)
			declaration = functions[function].declarators[0]
			enter_arguments = ' '.join(['this.args.push(args[{0}]);'.format(i) for i in range(len(declaration))])
			hook = hook.replace('__ENTERARGS__', enter_arguments)
			leave_arguments =  " + ', ' + ".join(["'{0}=' + this.args[{1}]".format(declaration[i][0], i) for i in range(len(declaration))])
			line = ' + '.join(["name", "'('", leave_arguments, "') = ' + result"])
			line = "console.log({0});".format(line)
			hook = hook.replace('__LEAVELOG__', line)
			output.append(hook)

	return output

outputfile = '/tmp/frida-hooks.js'

with open(outputfile, 'w') as f:
	for hook in generate_hooks('/usr/include/openssl/ssl.h'):
		print(hook)
		f.write(hook)
	for hook in generate_hooks('/usr/include/openssl/hmac.h'):
		print(hook)
		f.write(hook)