├── LICENSE.txt ├── Readme.md ├── pacxplorer.gif └── pacxplorer.py /LICENSE.txt: -------------------------------------------------------------------------------- 1 | GNU GENERAL PUBLIC LICENSE 2 | Version 3, 29 June 2007 3 | 4 | Copyright (C) 2007 Free Software Foundation, Inc. 5 | Everyone is permitted to copy and distribute verbatim copies 6 | of this license document, but changing it is not allowed. 7 | 8 | Preamble 9 | 10 | The GNU General Public License is a free, copyleft license for 11 | software and other kinds of works. 12 | 13 | The licenses for most software and other practical works are designed 14 | to take away your freedom to share and change the works. By contrast, 15 | the GNU General Public License is intended to guarantee your freedom to 16 | share and change all versions of a program--to make sure it remains free 17 | software for all its users. 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It is safest 630 | to attach them to the start of each source file to most effectively 631 | state the exclusion of warranty; and each file should have at least 632 | the "copyright" line and a pointer to where the full notice is found. 633 | 634 | 635 | Copyright (C) 636 | 637 | This program is free software: you can redistribute it and/or modify 638 | it under the terms of the GNU General Public License as published by 639 | the Free Software Foundation, either version 3 of the License, or 640 | (at your option) any later version. 641 | 642 | This program is distributed in the hope that it will be useful, 643 | but WITHOUT ANY WARRANTY; without even the implied warranty of 644 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 645 | GNU General Public License for more details. 646 | 647 | You should have received a copy of the GNU General Public License 648 | along with this program. If not, see . 649 | 650 | Also add information on how to contact you by electronic and paper mail. 651 | 652 | If the program does terminal interaction, make it output a short 653 | notice like this when it starts in an interactive mode: 654 | 655 | Copyright (C) 656 | This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. 657 | This is free software, and you are welcome to redistribute it 658 | under certain conditions; type `show c' for details. 659 | 660 | The hypothetical commands `show w' and `show c' should show the appropriate 661 | parts of the General Public License. Of course, your program's commands 662 | might be different; for a GUI interface, you would use an "about box". 663 | 664 | You should also get your employer (if you work as a programmer) or school, 665 | if any, to sign a "copyright disclaimer" for the program, if necessary. 666 | For more information on this, and how to apply and follow the GNU GPL, see 667 | . 668 | 669 | The GNU General Public License does not permit incorporating your program 670 | into proprietary programs. If your program is a subroutine library, you 671 | may consider it more useful to permit linking proprietary applications with 672 | the library. If this is what you want to do, use the GNU Lesser General 673 | Public License instead of this License. But first, please read 674 | . 675 | -------------------------------------------------------------------------------- /Readme.md: -------------------------------------------------------------------------------- 1 | # PacXplorer 2 | PacXplorer is an IDA plugin that adds XREFs between virtual functions and their call sites. 3 | This is accomplished by leveraging PAC codes in ARM64e binaries. 4 | ## Installation 5 | 1. install [ida-nentode](https://github.com/williballenthin/ida-netnode) somewhere IDA can import it 6 | 2. clone the repository and symlink `~/.idapro/plugins/pacxplorer.py` to `pacxplorer.py` in the cloned repo 7 | ## Usage 8 | 9 | ### Preliminary Analysis 10 | 1. open an IDB and make sure autoanalysis has finished 11 | 1.1. *KernelCache only:* make sure to run [ida_kernelcache(Cellebrite's fork)](https://github.com/cellebrite-srl/ida_kernelcache). This defines the `` `vtable for'`` symbols 12 | 2. from the menu select `Edit -> Plugins -> PacXplorer -> Analyse IDB` 13 | 2.2. if asked, point PacXplorer to the original input binary file that created the IDB 14 | * this will only happen if the original PAC codes are not present in the IDB and the input binary can't be located automatically 15 | 3. done! 16 | 17 | ### Continuous Use 18 | **TL;DR** 19 | 20 | `⌘-x` or `Right Click -> Jump to PAC XREFs` at suitable locations will open a selection window 21 | 22 | **From call site to virtual function** 23 | 1. place the cursor on a `MOVK` instruction near the call site to a virtual function (marked with a comment). 24 | 2. press the hotkey or activate the menu entry 25 | 3. a list of possible virtual methods called will open 26 | 4. if the same virtual function is called from several vtables, the `class` column will show `` instead of a class name 27 | * `Right click -> PAC: toggle unique function names` toggles this grouping 28 | 29 | **From virtual function to call site** 30 | 1. place the cursors either on a vtable entry or at the start of a virtual function 31 | 2. press the hotkey or activate the menu entry 32 | 3. a list of possible call sites will open 33 | 34 | ![](pacxplorer.gif) 35 | 36 | ## Principals of Operation 37 | PAC codes sign pointers with a _key_ and a _context_. 38 | [LLVM ABI](https://github.com/apple/llvm-project/blob/apple/master/clang/docs/PointerAuthentication.rst#c-virtual-functions) specifies that the *context* of vtable entries is a mix between the *entry's address* and a *hash* of the function prototype. 39 | 40 | Consider the following vtable at address `0x00000001 abcdef00`: 41 | 42 | 43 | | offset | method | hash | 44 | | :----: | :---: | :---: | 45 | | `0` | `foo()` | `0x1234` | 46 | | `8` | `bar()` | `0x9876` | 47 | 48 | The formula for calculating the context is: 49 | ```python 50 | addr_part = (addr_of_vtable + offset_of_method) & 0x0000ffffffffffff 51 | hash_part = (hash & 0xffff) << 48 52 | context = addr_part | hash_part 53 | ``` 54 | Hence when calling `bar()`, the context will be: `0x98760001 abcdef08`. 55 | 56 | Out of these factors, the *offset* of the method and the *hash* are known at compile time, but the actual *address of the vtable* is only known at runtime, through the `this` ptr (heck, this is the whole purpose of vtables to begin with). 57 | 58 | Therefore, a typical (simplified) code snippet might look as follows: 59 | ``` 60 | LDR X8, [X0] ; load vtable address 61 | LDRA X9, [X8,#0x18]! ; X8 = vtbl + offset 62 | MOVK X8, #0x68DA,LSL#48 ; set the hash 63 | BLRAA X9, X8 ; virtual call 64 | ``` 65 | PacXplorer looks for similar `MOVK` instructions in all of the defined functions and analyses the code leading up to them, noting the *offset* in the table and the *hash value*, and constructs *PAC tuple mappings* of `{(offset, hash): address of call}` 66 | 67 | On the other hand, PacXplorer iterates over all of the defined vtables, which it finds using symbol names. 68 | In the binary, each vtable contains *tagged pointers*, which will have been untagged by IDA. The pointer tags [embed](https://github.com/Synacktiv-contrib/kernelcache-laundering/blob/master/ios12_kernel_cache_helper.py) the hash values that are used for PAC. 69 | PacXplorer looks for the original pointer tags, which will have either been preserved in IDA's *patched bytes* window, or by opening the actual original binary. Using that, it creates the same *PAC tuple* for each virtual call, and construct a mapping of `{(offset, hash): entry in vtable}`. 70 | 71 | At runtime, a simple matching of these two mappings is performed. 72 | 73 | ## Q&A 74 | **Q: Why are there several virtual methods in the XREFs window?** 75 | **A:** This is the *inherent ambiguity* which is an intrinsic limitation of this method. 76 | For every class inheritance tree, when calling a virtual method that's present in the parent class and overloaded in some of the children, there is no knowing at compile time which overloaded version will actually get called. 77 | Obviously only what's known at compile time can be statically analysed. 78 | 79 | **Q: Why use a special window and not add the XREFs to the regular XREF list?** 80 | **A:** Due to the inherent ambiguity of which virtual function is called, I decided not to add (potentially many) bogus XREFs to the regular list, but keep them separated. 81 | 82 | **Q: Could there be false positives?** 83 | **A:** Yes. Besides the inherent ambiguity, there could also be cases where two functions in unrelated vtables generate the same (offset, hash) tuple. 84 | When trying out using the hash value alone (disregarding the offset in the vtable), I've encountered many such false positives. 85 | Using the combination of (offset, hash) I'm yet to observe any such false positives. 86 | 87 | **Q: Why is the XREF from the `MOVK` instruction and not the `BLRAA` call?** 88 | **A:** I've encountered instances of several virtual calls using the same BLRAA. 89 | Think of a function that selects a command handler with a switch-case, and all the cases jump to the same exit node that performs the call. 90 | 91 | **Q: Great stuff, I want to work with you!** 92 | **A:** Uhh, that's not really a question but thanks! [click here](https://www.cellebrite.com/en/about/careers/positions/?comeet_cat=israel&comeet_pos=0B.613&comeet_all=all&rd) (Remote talent welcome) 93 | 94 | ## Limitations 95 | 1. Works only on ARM64e binaries that conform to [the ABI](https://github.com/apple/llvm-project/blob/apple/master/clang/docs/PointerAuthentication.rst#c-virtual-functions) 96 | 2. Vtable symbols need to be present in the binary (`` `vtable for'``). In the case of the Kernel, [ida_kernelcache](https://github.com/cellebrite-srl/ida_kernelcache) needs to have been run. Note that the official version doesn't support recent Kernels, but Cellebrite's fork is up to date. 97 | 3. If the tagged pointers haven't been preserved in the IDB, the original binary is needed for the analysis stage (but not afterwards) 98 | 4. Hexrays support WIP 99 | 100 | ## Meta 101 | Authored by Ouri Lipner of Cellebrite Security Research Labs. \ 102 | Currently maintained by Omer Porzecanski of Cellebrite Security Research Labs. \ 103 | Developed and tested for IDA 7.5 - 7.7 on OS X, iOS 12.x - 15.4 beta 104 | 105 | -------------------------------------------------------------------------------- /pacxplorer.gif: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/cellebrite-labs/PacXplorer/7c785e2c04e1091437241f0b154b64bd4b78b72b/pacxplorer.gif -------------------------------------------------------------------------------- /pacxplorer.py: -------------------------------------------------------------------------------- 1 | # PacXplorer - IDA plugin to find code cross references to virtual functions using PAC codes 2 | # Copyright (C) 2019, 2020 Cellebrite DI LTD 3 | 4 | # This program is free software: you can redistribute it and/or modify 5 | # it under the terms of the GNU General Public License as published by 6 | # the Free Software Foundation, either version 3 of the License, or 7 | # (at your option) any later version. 8 | 9 | # This program is distributed in the hope that it will be useful, 10 | # but WITHOUT ANY WARRANTY; without even the implied warranty of 11 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 | # GNU General Public License for more details. 13 | 14 | # You should have received a copy of the GNU General Public License 15 | # along with this program. If not, see . 16 | 17 | from __future__ import print_function 18 | import mmap 19 | import idaapi 20 | import idc 21 | import idautils 22 | from netnode import Netnode 23 | from idaapi import Choose 24 | from collections import namedtuple 25 | from functools import wraps, partial 26 | import os 27 | import struct 28 | import sys 29 | 30 | PYTHON3 = sys.version_info.major == 3 31 | if PYTHON3: 32 | import pickle 33 | 34 | def iterkeys(dct): 35 | return iter(dct.keys()) 36 | 37 | def iteritems(dct): 38 | return iter(dct.items()) 39 | else: 40 | import cPickle as pickle 41 | 42 | iterkeys = dict.iterkeys 43 | iteritems = dict.iteritems 44 | 45 | NETNODE = "$ pacxplorer" 46 | 47 | DEBUG_VTABLE_SIZES = False 48 | FORCE_ORIG_BYTES_FROM_INPUT_FILE = False 49 | DEBUG_PATCHED_BYTES = False 50 | DEBUG_MULTIPLE_INHERITANCE = False 51 | 52 | 53 | class PickleNetNode(Netnode): 54 | @staticmethod 55 | def _encode(data): 56 | return pickle.dumps(data) 57 | 58 | @staticmethod 59 | def _decode(data): 60 | return pickle.loads(data) 61 | 62 | @staticmethod 63 | def cached(cache_key): 64 | """Decorator for returning cached values from self.cache[cache_key] for method with no arguments""" 65 | def decorator(method): 66 | @wraps(method) 67 | def wrapper(self): 68 | if hasattr(self, 'log'): 69 | log = self.log.info 70 | else: 71 | log = print 72 | 73 | cached_val = self.cache.get(cache_key) 74 | if cached_val is not None: 75 | log("Using cached value for %s" % cache_key) 76 | return cached_val 77 | log("No cached value for %s, generating..." % cache_key) 78 | result = method(self) 79 | self.cache[cache_key] = result 80 | log("Value for %s generated" % cache_key) 81 | return result 82 | return wrapper 83 | return decorator 84 | 85 | 86 | VtableXrefTuple = namedtuple('VtableXrefTuple', ['xref_to', 'vtable_addr', 'vtable_entry_addr', 'offset', 'pac']) 87 | 88 | 89 | class VtableAnalyzer(object): 90 | class PatchedBytesIDB(object): 91 | def __enter__(self): 92 | return self 93 | 94 | def __exit__(self, exc_type, exc_val, exc_tb): 95 | pass 96 | 97 | def get_original_qword(self, ea): 98 | return idaapi.get_original_qword(ea) 99 | 100 | class PatchedBytesFile(object): 101 | def __init__(self, filename): 102 | self.filename = filename 103 | self.mapping = None 104 | 105 | def __enter__(self): 106 | assert self.mapping is None 107 | with open(self.filename, 'rb') as f: 108 | # the mmap object dup()s the file descriptor 109 | self.mapping = mmap.mmap(f.fileno(), 0, mmap.MAP_PRIVATE, mmap.PROT_READ) 110 | 111 | return self 112 | 113 | def __exit__(self, exc_type, exc_val, exc_tb): 114 | self.mapping.close() 115 | self.mapping = None 116 | 117 | def get_original_qword(self, ea): 118 | assert self.mapping is not None 119 | 120 | file_offset = idaapi.get_fileregion_offset(ea) 121 | try: 122 | if file_offset == -1: 123 | raise IndexError() 124 | return struct.unpack_from(" 1: 175 | symbol += 'N' 176 | for name in scopes: 177 | if len(name) == 0: 178 | return None 179 | symbol += '{}{}'.format(len(name), name) 180 | if len(scopes) > 1: 181 | symbol += 'E' 182 | return symbol 183 | 184 | # Taken from ida_kernelcache.symbol, to remove the dependency 185 | @classmethod 186 | def vtable_symbol_for_class(cls, classname): 187 | """Get the mangled symbol name for the vtable for the given class name. 188 | 189 | Arguments: 190 | classname: The name of the C++ class. 191 | 192 | Returns: 193 | The symbol name, or None if the classname is invalid. 194 | """ 195 | name = cls._mangle_name(classname.split('::')) 196 | if not name: 197 | return None 198 | return '__ZTV' + name 199 | 200 | VTABLE_SUFFIX = '::vtable' 201 | SUFFIX_LEN = len(VTABLE_SUFFIX) 202 | 203 | @PickleNetNode.cached('vtable_struct_sizes') 204 | def collect_all_vtable_struct_sizes(self): 205 | """ 206 | Generate a disctionary of : for all the vtables, based on defined structs. 207 | Iterates all structs with names that end with ::vtable (generated by ida_kernelcache). 208 | """ 209 | sizes = {self.vtable_symbol_for_class(name[:-self.SUFFIX_LEN]): idaapi.get_struc_size(struct_id) 210 | for _, struct_id, name in idautils.Structs() if name.endswith(self.VTABLE_SUFFIX)} 211 | return sizes 212 | 213 | @staticmethod 214 | def iter_name_ea(names): 215 | for name in names: 216 | yield name, idc.get_name_ea_simple(name) 217 | 218 | @PickleNetNode.cached('vtable_eas2') 219 | def collect_all_vtable_eas(self): 220 | """Generate a dictionary of : for all the vtables whose sizes we know""" 221 | vtables = {} 222 | for ea, name in idautils.Names(): 223 | if ea == idc.BADADDR or name is None: 224 | continue 225 | if name.startswith('__ZTV') or name.startswith('_ZTV'): 226 | demangled = idaapi.demangle_name(name, idaapi.inf_get_short_demnames()) 227 | if not demangled or not demangled.startswith("`vtable for'"): 228 | print("pacxplorer: warning, name %s, demangled %s, does not seem to be a vtable" % 229 | (name, repr(demangled))) 230 | continue 231 | vtables[ea] = name 232 | 233 | if DEBUG_VTABLE_SIZES: 234 | printed = False 235 | for name, ea in self.iter_name_ea(self.vtable_struct_sizes): 236 | if ea == idc.BADADDR: 237 | continue 238 | if ea not in vtables: 239 | print("pacxplorer: warning, vtable %s @ 0x%x is only found using the legacy method" % 240 | (name, ea)) 241 | printed = True 242 | if not printed: 243 | print("all legacy vtables were accounted for using new method") 244 | 245 | return vtables 246 | 247 | # Based on https://github.com/Synacktiv-contrib/kernelcache-laundering/blob/master/ios12_kernel_cache_helper.py 248 | @staticmethod 249 | def get_pac(decorated_addr): 250 | """Return MOVK pac code from decorated pointer""" 251 | if decorated_addr & 0x4000000000000000 != 0: 252 | return None 253 | if decorated_addr & 0x8000000000000000 == 0: 254 | return None 255 | return (decorated_addr >> 32) & 0xFFFF 256 | 257 | @staticmethod 258 | def _patched_bytes_in_idb(): 259 | if FORCE_ORIG_BYTES_FROM_INPUT_FILE: 260 | return False 261 | 262 | # For now, we just check if tehere are ANY patched bytes in the IDB, 263 | # and assume that patches correspond to PAC codes being present in the IDB. 264 | # This of course doesn't always hold, but in practice, others uses for patches are rare. 265 | have_patches = bool(idaapi.visit_patched_bytes(0, idc.BADADDR, lambda *x: 1)) 266 | return have_patches 267 | 268 | @PickleNetNode.cached('vtable_pac_xrefs') 269 | def generate_pac_xrefs(self): 270 | """ 271 | The main functionality of the vtable analysis module: 272 | Generates two way xrefs: 273 | a. from pac code to method, remembering all the different vtables that reach this method 274 | b. from method to pac code(s), remembering all the different vtables, 275 | and supporting the unlikely case of various pac code for the same method 276 | 277 | Returns: 278 | funcs_by_code_dict: dict of : 279 | codes_by_func_dict: dict of :: > 280 | 281 | """ 282 | funcs_by_code_dict = {} 283 | codes_by_func_dict = {} 284 | 285 | _patched_bytes_obj = self.PatchedBytesIDB() if self.use_patched_bytes else \ 286 | self.PatchedBytesFile(self.file_to_open) 287 | 288 | with _patched_bytes_obj as patched_bytes: 289 | """ 290 | In case of multiple inheritance, the vtable contains more concatenated vtables in a special way. 291 | We need to parse the concatenated vtables of the base classes as well as the main one. 292 | 293 | vtable layout with multiple inheritance can look like this: 294 | 295 | 296 | vmethod 1 297 | ... 298 | vmethod n 299 | 300 | --> this is the vtable of one of the base classes 301 | --> same rtti as before 302 | vmethod n+1 303 | ... 304 | vmethod m 305 | 306 | --> another base class 307 | < etc > 308 | """ 309 | 310 | for ea, vtable_symbol in iteritems(self.vtable_eas): 311 | 312 | first_rtti_ptr = idaapi.get_qword(ea + 8) 313 | # first section of the vtable - main vtable. 314 | # mostly, this is the only part there is. 315 | # If there are concatenated vtables due to multiple inheritance, iterate over them. 316 | while True: 317 | ea += 16 # skip 'this offset' and rtti in vtable 318 | # offset in the current vtable 319 | offset = 0 320 | # now iterate over vmethods 321 | while True: 322 | orig_qword = patched_bytes.get_original_qword(ea + offset) 323 | patched_qword = idaapi.get_qword(ea + offset) 324 | if DEBUG_PATCHED_BYTES and orig_qword is None: 325 | print("orig_qword is None") 326 | print("ea 0x%x, offset 0x%x" % (ea, offset)) 327 | print("symbol: %s" % vtable_symbol) 328 | 329 | # end of the vtable is detected by encountering not a tagged pointer 330 | # this is okay even if there are severl conjoined vtables back-to-back, 331 | # due to the first non-ptr element in the vtable 332 | if orig_qword == patched_qword or orig_qword is None: 333 | if DEBUG_VTABLE_SIZES: 334 | size = self.vtable_struct_sizes.get(vtable_symbol) 335 | if size is not None and offset != size: 336 | print("%s @ 0x%x: non-matching sizes: old 0x%x, new 0x%x" % 337 | (vtable_symbol, ea+size, size, offset)) 338 | break 339 | 340 | # this is expected to always succeed 341 | pac = self.get_pac(orig_qword) 342 | if pac is not None: 343 | xref_to = idaapi.get_qword(ea + offset) 344 | 345 | # VtableXrefTuple = namedtuple('VtableXrefTuple', ['xref_to' , 'vtable_addr', 'vtable_entry_addr', 'offset', 'pac']) 346 | xref_tuple = VtableXrefTuple(xref_to, ea-16, ea + offset, offset, pac) 347 | refs = funcs_by_code_dict.setdefault((offset, pac), []) 348 | refs.append(xref_tuple) 349 | 350 | codes_dict = codes_by_func_dict.setdefault(xref_to, {}) 351 | refs = codes_dict.setdefault((offset, pac), []) 352 | refs.append(xref_tuple) 353 | 354 | offset += 8 355 | 356 | # if we haven't parsed anything in the inner loop, no need to process this whole vtable any more 357 | if offset == 0: 358 | break 359 | # in the context of the concatenated vtables loop, skip past the vtable we have just finished 360 | ea += offset 361 | rtti_ptr = idaapi.get_qword(ea + 8) 362 | # we know there is an concatenated vtable only by encountering the same rtti ptr as the main one. 363 | # normal case: not concatenated vtable, so break after one iteration 364 | if first_rtti_ptr == 0 or rtti_ptr != first_rtti_ptr: 365 | break 366 | else: 367 | if DEBUG_MULTIPLE_INHERITANCE: 368 | print("parsing concatenated vtable at 0x%x, symbol %s " % (ea, vtable_symbol)) 369 | 370 | return funcs_by_code_dict, codes_by_func_dict 371 | 372 | 373 | MovkCodeTuple = namedtuple('MovkCodeTuple', ['pac_tuple', 'movk_addr', 'trace']) 374 | 375 | 376 | class MovkAnalyzer(object): 377 | GOOD_MOVK_COMMENT = 'This MOVK has PAC xrefs' 378 | BAD_STATICVTBL_MOVK_COMMENT = 'This MOVK has **NO** PAC xrefs (static vtable)' 379 | BAD_ERROR_MOVK_COMMENT = 'This MOVK has **NO** PAC xrefs (analysis error, please report!)' 380 | BAD_INDIRECT_REG_VAL = 'Could not find register value for indirect op (analysis error, please report!)' 381 | 382 | def __init__(self, cache): 383 | self.cache = cache # cache for analyzed data 384 | self.codes_by_movk_dict = None 385 | self.movk_by_code_dict = None 386 | 387 | def analyze(self): 388 | self.codes_by_movk_dict, self.movk_by_code_dict = self.analyze_all_funcs() 389 | print('MOVK analysis done') 390 | 391 | def can_xref_from_ea(self, ea): 392 | code = self.codes_by_movk_dict.get(ea) 393 | return ea if (code and code.pac_tuple) else None 394 | 395 | def pac_tuple_from_ea(self, ea): 396 | # MovkCodeTuple = namedtuple('MovkCodeTuple', ['pac_tuple', 'movk_addr', 'trace']) 397 | movk_code_tuple = self.codes_by_movk_dict.get(ea) 398 | if movk_code_tuple is None: 399 | return None 400 | return movk_code_tuple.pac_tuple 401 | 402 | def movks_from_pac_codes(self, pac_codes): 403 | movks = [] 404 | for code in pac_codes: 405 | for movk in self.movk_by_code_dict.get(code, []): 406 | movks.append((movk, code)) 407 | 408 | return movks 409 | 410 | @classmethod 411 | def edit_comment(cls, comment, wanted, delete): 412 | if comment is None: 413 | comment = "" 414 | if not delete and wanted not in comment: 415 | comment = comment.rstrip() 416 | if comment: 417 | comment += '\n' 418 | comment += wanted 419 | elif delete and wanted in comment: 420 | parts = comment.split(wanted) 421 | comment = '\n'.join((x.rstrip() for x in parts)) 422 | return comment 423 | 424 | @classmethod 425 | def add_comment(cls, ea, wanted): 426 | comment = idc.get_cmt(ea, True) 427 | new_comment = cls.edit_comment(comment, wanted, delete=False) 428 | idc.set_cmt(ea, new_comment, True) 429 | 430 | @classmethod 431 | def delete_comment(cls, ea, wanted): 432 | comment = idc.get_cmt(ea, True) 433 | new_comment = cls.edit_comment(comment, wanted, delete=True) 434 | idc.set_cmt(ea, new_comment, True) 435 | 436 | @staticmethod 437 | def does_modify_reg(insn, reg): 438 | for i in range(6): 439 | op = insn.ops[i] 440 | if op.reg != reg: 441 | continue 442 | if insn.get_canon_feature() & (0x4 << i): # CF_CHG1, CF_CHG2, ... 443 | return True 444 | return False 445 | 446 | @staticmethod 447 | def does_use_reg(insn, reg): 448 | for i in range(6): 449 | op = insn.ops[i] 450 | if op.reg != reg: 451 | continue 452 | if insn.get_canon_feature() & (0x100 << i): # CF_USE1, CF_USE2, ... 453 | return True 454 | return False 455 | 456 | @staticmethod 457 | def does_use_any_reg(insn): 458 | for i in range(6): 459 | op = insn.ops[i] 460 | if op.reg == 0: 461 | continue 462 | if insn.get_canon_feature() & (0x100 << i): # CF_USE1, CF_USE2, ... 463 | return True 464 | return False 465 | 466 | @classmethod 467 | def analyze_movk(cls, addr): 468 | trace = [] 469 | seen_depac = False 470 | offset = 0 471 | 472 | cur_func = idaapi.get_func(addr) 473 | if not cur_func: 474 | return (None, None) 475 | cur_func_start = cur_func.start_ea 476 | 477 | insn = idautils.DecodeInstruction(addr) 478 | mnem = insn.get_canon_mnem() 479 | if mnem != 'MOVK' or insn.Op2.specval != 48: 480 | return (None, None) 481 | ctx_reg = insn.Op1.reg 482 | movk_code = insn.Op2.value 483 | 484 | line = idc.GetDisasm(insn.ea) 485 | trace.append(line) 486 | 487 | curr = addr 488 | visited = set() 489 | while True: 490 | refs = [x for x in idautils.CodeRefsTo(curr, True) if idaapi.get_func(x) and idaapi.get_func(x).start_ea == cur_func_start] 491 | if not refs: 492 | trace.append('ERROR NO REFS') 493 | break 494 | 495 | curr = refs[0] 496 | if curr in visited: 497 | trace.append('ERROR EXHAUSTED') 498 | break 499 | 500 | visited.add(curr) 501 | 502 | insn = idautils.DecodeInstruction(curr) 503 | mnem = insn.get_canon_mnem() 504 | line = idc.GetDisasm(insn.ea) 505 | line = line.split(';')[0] # line comments get into the dissasembly 506 | line_parts = [x for x in line.split(' ') if x] 507 | 508 | trace.append(line) 509 | 510 | if line_parts[0:1] == ['LDRAA'] and line_parts[-1:] and line_parts[-1:][0].endswith('!') and \ 511 | insn.Op2.reg == ctx_reg: 512 | offset = insn.Op2.addr 513 | seen_depac = True 514 | break 515 | if line_parts and line_parts[0] in ['AUTDZA', 'AUTDA'] and insn.Op1.reg == ctx_reg: 516 | seen_depac = True 517 | break 518 | if cls.does_modify_reg(insn, ctx_reg): 519 | if not cls.does_use_any_reg(insn): 520 | trace.append('ERROR STATIC VTABLE') 521 | cls.add_comment(addr, cls.BAD_STATICVTBL_MOVK_COMMENT) 522 | break 523 | elif mnem == 'MOV': 524 | ctx_reg = insn.Op2.reg 525 | elif mnem == 'ADD': 526 | ctx_reg = insn.Op2.reg 527 | if insn.Op3.type == idaapi.o_idpspec0: 528 | indirect_reg = insn.Op3.reg 529 | sliding_ea = insn.ea 530 | while sliding_ea >= cur_func_start: 531 | prev_insn, _ = idautils.DecodePrecedingInstruction(sliding_ea) 532 | 533 | if prev_insn is None: 534 | trace.append('ERROR FINDING VALUE FOR REG IN INDIRECT OP') 535 | cls.add_comment(sliding_ea, cls.BAD_INDIRECT_REG_VAL) 536 | break 537 | elif prev_insn.get_canon_mnem() == "MOV" and prev_insn.Op1.reg == indirect_reg: 538 | offset += prev_insn.Op2.value 539 | break 540 | 541 | sliding_ea = prev_insn.ea 542 | else: 543 | offset += insn.Op3.value 544 | else: 545 | trace.append('ERROR BAD MODIFY') 546 | #cls.add_comment(addr, cls.BAD_ERROR_MOVK_COMMENT) 547 | break 548 | elif cls.does_use_reg(insn, ctx_reg) and line_parts[-1:] and line_parts[-1:][0].endswith('!'): 549 | if mnem == 'LDR' and insn.Op2.reg == ctx_reg: 550 | offset += insn.Op2.addr 551 | else: 552 | trace.append('ERROR BAD MODIFY') 553 | #cls.add_comment(addr, cls.BAD_ERROR_MOVK_COMMENT) 554 | break 555 | 556 | trace = trace[::-1] 557 | pac_tuple = (offset, movk_code) if seen_depac else None 558 | 559 | if pac_tuple is not None: 560 | cls.add_comment(addr, cls.GOOD_MOVK_COMMENT) 561 | 562 | return (pac_tuple, trace) 563 | 564 | def _analyze_func(self, func_addr, codes_by_movk_dict, movk_by_code_dict): 565 | for addr in idautils.FuncItems(func_addr): 566 | pac_tuple, trace = self.analyze_movk(addr) 567 | if not (pac_tuple is None and trace is None): 568 | codes_by_movk_dict[addr] = MovkCodeTuple(pac_tuple, addr, trace) 569 | if pac_tuple is not None: 570 | movks = movk_by_code_dict.setdefault(pac_tuple, []) 571 | movks.append(addr) 572 | 573 | @PickleNetNode.cached('movk_analysis') 574 | def analyze_all_funcs(self): 575 | codes_by_movk_dict = {} 576 | movk_by_code_dict = {} 577 | for func in idautils.Functions(): 578 | self._analyze_func(func, codes_by_movk_dict, movk_by_code_dict) 579 | 580 | return codes_by_movk_dict, movk_by_code_dict 581 | 582 | 583 | class _Choose(Choose): 584 | # Fix Choose.UI_Hooks_Trampoline to work with modal dialogs 585 | class UI_Hooks_Trampoline(Choose.UI_Hooks_Trampoline): 586 | def populating_widget_popup(self, form, popup_handle): 587 | chooser = self.v() 588 | if hasattr(chooser, "OnPopup") and \ 589 | callable(getattr(chooser, "OnPopup")): 590 | chooser.OnPopup(form, popup_handle) 591 | 592 | class chooser_handler_t(idaapi.action_handler_t): 593 | def __init__(self, handler): 594 | idaapi.action_handler_t.__init__(self) 595 | self.handler = handler 596 | 597 | def activate(self, ctx): 598 | self.handler() 599 | return 1 600 | 601 | def update(self, ctx): 602 | return idaapi.AST_ENABLE_FOR_WIDGET \ 603 | if idaapi.is_chooser_widget(ctx.widget_type) \ 604 | else idaapi.AST_DISABLE_FOR_WIDGET 605 | 606 | def __init__(self, title, items, columns): 607 | Choose.__init__( 608 | self, 609 | title, 610 | columns, 611 | flags=Choose.CH_RESTORE) 612 | 613 | self.items = items 614 | 615 | def OnGetSize(self): 616 | return len(self.items) 617 | 618 | def OnGetLine(self, n): 619 | return self.items[n] 620 | 621 | def show(self): 622 | selected = self.Show(modal=True) 623 | if selected < 0: 624 | return None 625 | return self.items[selected] 626 | 627 | 628 | class MovkXrefChooser(_Choose): 629 | unique_functions = True 630 | 631 | def __init__(self, title, items): 632 | _Choose.__init__( 633 | self, 634 | title, 635 | items, 636 | [ ["Address", 20 | Choose.CHCOL_HEX], ["Method", 40 | Choose.CHCOL_PLAIN], 637 | ["Class", 30 | Choose.CHCOL_PLAIN] ]) 638 | 639 | self.all_items = items 640 | self.calculate_unique() 641 | 642 | def OnPopup(self, form, popup_handle): 643 | idaapi.attach_action_to_popup(form, popup_handle, "-", None, idaapi.SETMENU_FIRST) 644 | 645 | desc = idaapi.action_desc_t( 646 | "choose:unique", 647 | "PAC: toggle unique function names", 648 | self.chooser_handler_t(self.toggle_unique)) 649 | idaapi.attach_dynamic_action_to_popup(form, popup_handle, desc, None, idaapi.SETMENU_FIRST) 650 | 651 | def OnRefresh(self, n): 652 | return (Choose.ALL_CHANGED, 0) 653 | 654 | def calculate_unique(self): 655 | if MovkXrefChooser.unique_functions: 656 | unique_dict = {} 657 | for addr, func, classname in self.all_items: 658 | if classname != unique_dict.setdefault((addr, func), classname): 659 | unique_dict[(addr, func)] = '' 660 | self.items = list(sorted( ([addr, funcname, classname] for (addr, funcname), classname in 661 | iteritems(unique_dict)), key=lambda x: x[0])) 662 | else: 663 | self.items = self.all_items 664 | 665 | def toggle_unique(self): 666 | MovkXrefChooser.unique_functions = not MovkXrefChooser.unique_functions 667 | self.calculate_unique() 668 | self.Refresh() 669 | 670 | @staticmethod 671 | def demangle(ea): 672 | name = idc.get_name(ea, idc.GN_LONG) 673 | demangled = (idaapi.demangle_name(str(name), idc.get_inf_attr(idc.INF_SHORT_DEMNAMES)) or '').\ 674 | replace("`vtable for'", "") 675 | return demangled or name 676 | 677 | 678 | class FuncXrefChooser(_Choose): 679 | def __init__(self, title, items): 680 | _Choose.__init__( 681 | self, 682 | title, 683 | items, 684 | [ ["Address", 30 | Choose.CHCOL_PLAIN], ["Address (Hex)", 20 | Choose.CHCOL_HEX], 685 | ["PAC Code", 20 | Choose.CHCOL_PLAIN] ]) 686 | 687 | 688 | class PacxplorerPlugin(idaapi.plugin_t, idaapi.UI_Hooks): 689 | plugin_initialized = False 690 | flags = idaapi.PLUGIN_MOD | idaapi.PLUGIN_HIDE 691 | comment = "find xrefs for vtable methods using PAC codes" 692 | help = "" 693 | wanted_name = "PacXplorer" 694 | wanted_hotkey = "" 695 | 696 | class MenuBase(idaapi.action_handler_t): 697 | label = None 698 | shortcut = None 699 | tooltip = None 700 | icon = -1 701 | 702 | def __init__(self, plugin): 703 | self.plugin = plugin 704 | self.name = self.plugin.wanted_name + ':' + self.__class__.__name__ 705 | self.register() 706 | 707 | def register(self): 708 | return idaapi.register_action(idaapi.action_desc_t( 709 | self.name, # Name. Acts as an ID. Must be unique. 710 | self.label, # Label. That's what users see. 711 | self, # Handler. Called when activated, and for updating 712 | self.shortcut, # shortcut, 713 | self.tooltip, # tooltip 714 | self.icon # icon 715 | )) 716 | 717 | def unregister(self): 718 | """Unregister the action. 719 | After unregistering the class cannot be used. 720 | """ 721 | idaapi.unregister_action(self.__name__) 722 | 723 | def activate(self, ctx): 724 | # dummy method 725 | return 1 726 | 727 | def update(self, ctx): 728 | return idaapi.AST_ENABLE_ALWAYS 729 | 730 | def path(self): 731 | return "Edit/Plugins/" + self.plugin.wanted_name + "/" + self.label 732 | 733 | def get_name(self): 734 | return self.name 735 | 736 | class AnalyzeMenu(MenuBase): 737 | label = 'Analyze IDB...' 738 | 739 | def activate(self, ctx): 740 | self.plugin.analyze() 741 | return 1 742 | 743 | class JumpXrefMenu(MenuBase): 744 | label = 'Jump to PAC XREFs...' 745 | shortcut = 'Meta-X' 746 | icon = 151 747 | 748 | def activate(self, ctx): 749 | self.plugin.choose_window_here() 750 | return 1 751 | 752 | def update(self, ctx): 753 | return idaapi.AST_ENABLE if self.plugin.can_find_xrefs_here() else idaapi.AST_DISABLE 754 | 755 | def __init__(self): 756 | self.analysis_done = False 757 | self.vtable_analyzer = None 758 | self.movk_analyzer = None 759 | self.ui_hook = False 760 | self.analyze_menu = None 761 | self.jump_xref_menu = None 762 | 763 | def init(self): 764 | """plugin_t init() function""" 765 | super(PacxplorerPlugin, self).__init__() 766 | 767 | typename = idaapi.get_file_type_name().lower() 768 | if 'arm64e' not in typename: 769 | print('%s: IDB deemed unsuitable (not an ARM64e binary). Skipping...' % self.wanted_name) 770 | return idaapi.PLUGIN_SKIP 771 | 772 | if not PacxplorerPlugin.plugin_initialized: 773 | self.analyze_menu = self.AnalyzeMenu(self) 774 | self.jump_xref_menu = self.JumpXrefMenu(self) 775 | 776 | self.ui_hook = True 777 | self.hook() 778 | print('%s: IDB deemed suitable. Initializing...' % self.wanted_name) 779 | 780 | return idaapi.PLUGIN_KEEP 781 | 782 | def run(self, arg=0): 783 | """plugin_t run() implementation""" 784 | return 785 | 786 | def term(self): 787 | """plugin_t term() implementation""" 788 | if self.ui_hook: 789 | self.unhook() 790 | self.ui_hook = False 791 | return 792 | 793 | def ready_to_run(self): 794 | """UI_Hooks function. 795 | Attaches actions to plugin in main menu. 796 | """ 797 | 798 | idaapi.attach_action_to_menu(self.analyze_menu.path(), self.analyze_menu.get_name(), idaapi.SETMENU_APP) 799 | idaapi.attach_action_to_menu(self.jump_xref_menu.path(), self.jump_xref_menu.get_name(), idaapi.SETMENU_APP) 800 | PacxplorerPlugin.plugin_initialized = True 801 | self.analyze(only_cached=True) 802 | 803 | def finish_populating_widget_popup(self, widget, popup_handle): 804 | """UI_Hooks function 805 | Attaches the Find Xref action to the dissasembly right click menu. 806 | """ 807 | if not self.analysis_done: 808 | return 809 | if idaapi.get_widget_type(widget) == idaapi.BWN_DISASM and self.can_find_xrefs_here(): 810 | idaapi.attach_action_to_popup(widget, popup_handle, "-", None, idaapi.SETMENU_FIRST) 811 | idaapi.attach_action_to_popup(widget, popup_handle, self.jump_xref_menu.get_name(), None, 812 | idaapi.SETMENU_FIRST) 813 | 814 | def analyze(self, only_cached=False): 815 | cache = PickleNetNode(NETNODE) 816 | # cache.kill() 817 | 818 | if only_cached: 819 | if not cache.get('analysis_done', False): 820 | return 821 | print('%s: this IDB had been previously analyzed, loading from cache' % self.wanted_name) 822 | elif self.analysis_done: 823 | answer = idc.ask_yn(idaapi.ASKBTN_NO, "HIDECANCEL\nRe-analyze the IDB?") 824 | if answer != idaapi.ASKBTN_YES: 825 | return 826 | cache.kill() 827 | self.analysis_done = False 828 | 829 | should_hide_wait = False 830 | if not cache.get('analysis_done', False): 831 | should_hide_wait = True 832 | idaapi.show_wait_box("HIDECANCEL\n%s analyzing..." % self.wanted_name) 833 | 834 | # not catching exceptions, just want to call the finally block to hide the wait_box 835 | try: 836 | self.vtable_analyzer = VtableAnalyzer(cache) 837 | self.movk_analyzer = MovkAnalyzer(cache) 838 | 839 | if not self.vtable_analyzer.use_patched_bytes: 840 | file_to_open = self.choose_file_for_patches() 841 | if file_to_open is None: 842 | print("%s: user cancelled" % self.wanted_name) 843 | return 844 | self.vtable_analyzer.file_to_open = file_to_open 845 | 846 | self.vtable_analyzer.analyze() 847 | if len(self.vtable_analyzer.funcs_by_code_dict) == 0: 848 | idaapi.warning(('%s\nUnable to find vtables and pac codes.\n' 849 | 'If this is a KernelCache:\n' 850 | 'make sure ida_kernelcache is run on this idb') % self.wanted_name) 851 | return 852 | 853 | self.movk_analyzer.analyze() 854 | if len(self.movk_analyzer.movk_by_code_dict) == 0: 855 | idaapi.warning('%s\nUnable to find movk pac codes.\nThis is weird...' % self.wanted_name) 856 | 857 | cache['analysis_done'] = True 858 | self.analysis_done = True 859 | finally: 860 | if should_hide_wait: 861 | idaapi.hide_wait_box() 862 | if not self.analysis_done: 863 | cache.kill() 864 | 865 | def choose_xref_from_movk(self, ea): 866 | pac_tuple = self.movk_analyzer.pac_tuple_from_ea(ea) 867 | if not pac_tuple: 868 | return None 869 | 870 | raw_candidates = self.vtable_analyzer.func_from_pac_tuple(pac_tuple) 871 | # VtableXrefTuple = namedtuple('VtableXrefTuple', ['xref_to' , 'vtable_addr', 'vtable_entry_addr', 'offset', 'pac']) 872 | candidates = [ ["0x%016x" % x.xref_to, MovkXrefChooser.demangle(x.xref_to), 873 | MovkXrefChooser.demangle(x.vtable_addr)] for x in raw_candidates ] 874 | title = "PAC xrefs from 0x%016X" % ea 875 | chooser = MovkXrefChooser(title, candidates) 876 | chosen = chooser.show() 877 | if chosen is None: 878 | return None 879 | return int(chosen[0], 16) 880 | 881 | def choose_xref_to_func(self, ea): 882 | pac_codes = self.vtable_analyzer.codes_from_func_addr(ea) 883 | if not pac_codes: 884 | return None 885 | 886 | movks = self.movk_analyzer.movks_from_pac_codes(pac_codes) 887 | candidates = [[idc.get_func_off_str(addr), "0x%016x" % addr, "(%d, 0x%4x)" % (code[0], code[1])] 888 | for addr, code in movks] 889 | 890 | title = 'PAC xrefs to 0x%016X' % ea 891 | chooser = FuncXrefChooser(title, candidates) 892 | chosen = chooser.show() 893 | 894 | if chosen is None: 895 | return None 896 | return int(chosen[1], 16) 897 | 898 | def pick_choose_func_for_ea(self, ea): 899 | ref_addr = self.movk_analyzer.can_xref_from_ea(ea) 900 | if ref_addr: 901 | return partial(self.choose_xref_from_movk, ref_addr) 902 | 903 | ref_addr = self.vtable_analyzer.can_xref_from_ea(ea) 904 | if ref_addr: 905 | return partial(self.choose_xref_to_func, ref_addr) 906 | 907 | return None 908 | 909 | def choose_by_ea(self, ea): 910 | choose_func = self.pick_choose_func_for_ea(ea) 911 | if choose_func is None: 912 | return 913 | 914 | addr = choose_func() 915 | if addr is not None: 916 | idc.jumpto(addr) 917 | 918 | def choose_window_here(self): 919 | if not self.analysis_done: 920 | return 921 | self.choose_by_ea(idc.here()) 922 | 923 | def can_find_xrefs_here(self): 924 | if not self.analysis_done: 925 | return False 926 | return self.pick_choose_func_for_ea(idc.here()) is not None 927 | 928 | def choose_file_for_patches(self): 929 | file_path = idaapi.get_input_file_path() 930 | if os.path.exists(file_path): 931 | return file_path 932 | else: 933 | idaapi.info('%s\nNo patches are present in the IDB.\n' 934 | 'Please locate the input binary, to load PAC codes from' % 935 | self.wanted_name) 936 | name = idaapi.ask_file(False, '*', 'locate the input binary') 937 | return name or None 938 | 939 | 940 | def PLUGIN_ENTRY(): 941 | return PacxplorerPlugin() 942 | --------------------------------------------------------------------------------