php2shell/tools/php2shell_offsets.py at main · devploit/php2shell · GitHub

Repository navigation

History

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

232

233

234

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

256

257

258

259

260

261

262

263

264

265

266

267

268

269

270

271

272

273

274

275

276

277

278

279

280

281

282

283

284

285

286

287

288

289

290

291

292

293

294

295

296

297

298

299

300

301

302

303

304

305

306

307

308

309

310

311

312

#!/usr/bin/env python3

"""

php2shell_offsets.py — extract libphp symbol offsets from PHP Docker images.

This fills the offset inventory for builds that have not been heap-calibrated.

It does not run the image: it creates a container, copies

/usr/lib/apache2/modules/libphp.so out, parses the ELF symbol table and writes

profiles/offsets/<version>-<arch>.json plus docs/offset-inventory.md.

Offsets alone do not give RCE. They are the per-build constants needed once a

heap profile exists; the dispatcher only runs verified profiles.

Usage:

python3 tools/php2shell_offsets.py

python3 tools/php2shell_offsets.py --images php:7.4-apache php:8.1-apache

"""

from __future__ import annotations

import argparse

import glob

import hashlib

import json

import os

import platform

import re

import shutil

import struct

import subprocess

import sys

HERE = os.path.dirname(os.path.abspath(__file__))

ROOT = os.path.dirname(HERE)

OUT = os.path.join(ROOT, "profiles", "offsets")

DOC = os.path.join(ROOT, "docs", "offset-inventory.md")

DEFAULT_IMAGES = [

"php:7.4-apache",

"php:8.0-apache",

"php:8.1-apache",

"php:8.2.34-apache",

"php:8.3.35-apache",

"php:8.4.26-apache",

"php:8.5.11-apache",

# Real-world subversions inside the vulnerable windows (same list as

# BUILDS in php2shell_matrix.py; pulled via a registry mirror when the

# Hub is rate-limited).

"php:8.4.2-apache",

"php:8.4.5-apache",

"php:8.4.6-apache",

"php:8.4.7-apache",

"php:8.4.8-apache",

"php:8.4.10-apache",

"php:8.4.11-apache",

"php:8.4.12-apache",

"php:8.4.13-apache",

"php:8.4.14-apache",

"php:8.4.15-apache",

"php:8.4.16-apache",

"php:8.4.17-apache",

"php:8.4.18-apache",

"php:8.4.19-apache",

"php:8.4.20-apache",

"php:8.4.25-apache",

"php:8.5.0-apache",

"php:8.5.1-apache",

"php:8.5.2-apache",

"php:8.5.3-apache",

"php:8.5.4-apache",

"php:8.5.5-apache",

"php:8.5.6-apache",

"php:8.5.7-apache",

"php:8.5.8-apache",

"php:8.5.9-apache",

"php:8.5.10-apache",

]

LIB_PATHS = [

"/usr/lib/apache2/modules/libphp.so",

"/usr/lib/apache2/modules/libphp7.so",

"/usr/lib/apache2/modules/libphp5.so",

]

SHT_SYMTAB = 2

SHT_DYNSYM = 11

PT_LOAD = 1

def docker(*args, timeout=900, text=True):

return subprocess.run(["docker", *args], capture_output=True, text=text, timeout=timeout)

def parse_elf(path: str):

with open(path, "rb") as handle:

data = handle.read()

if data[:4] != b"\x7fELF" or data[4] != 2 or data[5] != 1:

raise ValueError("not a little-endian ELF64 file")

e_phoff, = struct.unpack_from("<Q", data, 0x20)

e_shoff, = struct.unpack_from("<Q", data, 0x28)

e_phentsize, e_phnum = struct.unpack_from("<HH", data, 0x36)

e_shentsize, e_shnum = struct.unpack_from("<HH", data, 0x3A)

loads = []

for i in range(e_phnum):

off = e_phoff + i * e_phentsize

p_type, = struct.unpack_from("<I", data, off)

p_vaddr, = struct.unpack_from("<Q", data, off + 16)

p_memsz, = struct.unpack_from("<Q", data, off + 40)

if p_type == PT_LOAD and p_memsz:

loads.append(p_vaddr)

bias = min(loads) if loads else 0

sections = []

for i in range(e_shnum):

off = e_shoff + i * e_shentsize

name_off, sh_type = struct.unpack_from("<II", data, off)

sh_offset, sh_size = struct.unpack_from("<QQ", data, off + 24)

sh_link, = struct.unpack_from("<I", data, off + 40)

sh_entsize, = struct.unpack_from("<Q", data, off + 56)

sections.append({"type": sh_type, "offset": sh_offset, "size": sh_size,

"link": sh_link, "entsize": sh_entsize})

wanted = {"zif_system": None, "zval_ptr_dtor": None, "ps_globals": None}

for sec in sections:

if sec["type"] not in (SHT_SYMTAB, SHT_DYNSYM):

continue

if sec["link"] >= len(sections):

continue

strtab = sections[sec["link"]]

entsize = sec["entsize"] or 24

for i in range(sec["size"] // entsize):

off = sec["offset"] + i * entsize

st_name, = struct.unpack_from("<I", data, off)

st_value, = struct.unpack_from("<Q", data, off + 8)

if not st_name:

continue

name_off = strtab["offset"] + st_name

end = data.find(b"\x00", name_off)

if end < 0:

continue

name = data[name_off:end].decode("ascii", "replace")

if name in wanted and wanted[name] is None:

wanted[name] = st_value

return bias, wanted

def image_env(image: str) -> dict:

out = docker("inspect", "--format",

"{{range .Config.Env}}{{println .}}{{end}}", image)

env = {}

for line in out.stdout.splitlines():

if "=" in line:

k, v = line.split("=", 1)

env[k.strip()] = v.strip()

return env

def image_arch(image: str) -> str:

# Some imported/emulated images report an empty Architecture, so ask the

# image itself. uname inside the container is authoritative.

out = docker("run", "--rm", "--entrypoint", "uname", image, "-m", timeout=120)

machine = out.stdout.strip().lower()

if machine:

mapped = {"aarch64": "aarch64", "arm64": "aarch64",

"x86_64": "amd64", "amd64": "amd64"}.get(machine)

if mapped:

return mapped

out = docker("inspect", "--format", "{{.Architecture}}", image)

arch = out.stdout.strip()

if not arch or arch == "unknown":

machine = platform.machine().lower()

arch = {"aarch64": "aarch64", "arm64": "aarch64", "x86_64": "amd64"}.get(machine, machine)

return arch

def extract(image: str) -> dict:

name = "p2s-off-" + image.replace(":", "-").replace("/", "-")

docker("rm", "-f", name)

print(f"[*] {image}: creating container", flush=True)

created = docker("create", "--name", name, image, timeout=900)

if created.returncode != 0:

return {"image": image, "status": "pull/create failed",

"error": created.stderr.strip()[:200]}

try:

lib = None

for candidate in LIB_PATHS:

target = f"/tmp/{name}.so"

cp = docker("cp", f"{name}:{candidate}", target)

if cp.returncode == 0:

lib = target

break

if not lib:

return {"image": image, "status": "libphp not found"}

bias, symbols = parse_elf(lib)

with open(lib, "rb") as handle:

sha = hashlib.sha256(handle.read()).hexdigest()

env = image_env(image)

version = env.get("PHP_VERSION", "")

if not version:

tag = re.search(r"php:(\d+\.\d+\.\d+)", image)

version = tag.group(1) if tag else ""

arch = image_arch(image)

result = {

"image": image,

"php_version": version,

"branch": ".".join(version.split(".")[:2]) if version else "",

"arch": arch,

"libphp": {k: (hex(v) if v is not None else None) for k, v in symbols.items()},

"libphp_sha256": sha,

"status": "offsets extracted; heap not calibrated",

}

os.makedirs(OUT, exist_ok=True)

path = os.path.join(OUT, f"{version or name}-{arch}.json")

with open(path, "w", encoding="utf-8") as fh:

json.dump(result, fh, indent=2)

result["file"] = os.path.relpath(path, ROOT)

print(f" PHP {version} {arch}: zif={result['libphp']['zif_system']} "

f"dtor={result['libphp']['zval_ptr_dtor']}", flush=True)

return result

finally:

docker("rm", "-f", name)

def heap_status(version: str, arch: str) -> str | None:

"""Cross-reference profiles/ for a heap calibration of this build.

Only calibrations against official images count: those profiles are named

<version>-<distro>-<arch>.json (or <version>-bookworm-<arch>.json from the

author's runs). Lab builds such as 8.3.0-bookworm.json use a different

libphp binary and must not vouch for the official image.

"""

best = None

for path in glob.glob(os.path.join(ROOT, "profiles", f"*-{arch}.json")):

try:

with open(path, encoding="utf-8") as fh:

p = json.load(fh)

except (OSError, ValueError):

continue

if p.get("php_version") != version or p.get("arch") != arch:

continue

rank = (3 if p.get("rce") else

2 if p.get("measured", {}).get("libphp_base") else

1 if p.get("measured", {}).get("chunk_base") else 0)

if best is None or rank > best[0]:

best = (rank, p)

if best is None:

return None

return {3: "heap calibrated; RCE verified",

2: "heap calibrated; leaks only",

1: "heap calibrated; stage-1 leak only",

0: "heap calibrated; leak not reproduced"}[best[0]]

def write_doc(results) -> None:

entries = {}

for path in glob.glob(os.path.join(OUT, "*.json")):

try:

with open(path, encoding="utf-8") as fh:

item = json.load(fh)

except (OSError, ValueError):

continue

entries[(item.get("php_version"), item.get("arch"), item.get("image"))] = item

for item in results:

if item.get("libphp"):

entries[(item.get("php_version"), item.get("arch"), item.get("image"))] = item

ordered = sorted(entries.values(),

key=lambda r: tuple(int(x) if x.isdigit() else 0

for x in (r.get("php_version") or "0").split(".")))

lines = [

"# libphp offset inventory",

"",

"Generated by `tools/php2shell_offsets.py`. These are symbol offsets only:",

"a build still needs heap calibration before the chain can run.",

"",

"| --- | --- | --- | --- | --- | --- | --- |",

]

for r in ordered:

lib = r.get("libphp") or {}

status = heap_status(r.get("php_version", "?"), r.get("arch", "?")) \

or r.get("status", "")

lines.append("| {image} | {php} | {arch} | {zif} | {dtor} | {sha} | {status} |".format(

image=r.get("image", ""), php=r.get("php_version", "?"),

arch=r.get("arch", "?"), zif=lib.get("zif_system") or "-",

dtor=lib.get("zval_ptr_dtor") or "-",

sha=(r.get("libphp_sha256") or "-")[:12], status=status))

lines += ["", "## Notes", "",

"- Offsets are relative to the `libphp.so` load base; ASLR changes the base, not the offset.",

"- The same PHP version built by another distribution/arch has different offsets.",

"- Heap parameters (`stage1_n`, forge length, `htdata`, pads) are not included here;",

" run `tools/php2shell_calibrate.py` against a replica of the build for those.",

""]

os.makedirs(os.path.dirname(DOC), exist_ok=True)

with open(DOC, "w", encoding="utf-8") as fh:

fh.write("\n".join(lines))

def main() -> int:

ap = argparse.ArgumentParser(description="Extract libphp offsets from PHP images.")

ap.add_argument("--images", nargs="*", default=DEFAULT_IMAGES)

args = ap.parse_args()

if not shutil.which("docker"):

print("docker not found", file=sys.stderr)

return 4

results = [extract(image) for image in args.images]

write_doc(results)

print(f"[*] wrote {DOC}")

return 0

if __name__ == "__main__":

sys.exit(main())

php2shell/tools/php2shell_offsets.py at main · devploit/php2shell · GitHub

Repository navigation

Expand file tree

Breadcrumbs

php2shell_offsets.py

Latest commit

History

Breadcrumbs

php2shell_offsets.py

File metadata and controls