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6d6b4b2 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 | #!/usr/bin/env python3
"""Run analysis Python while denying network and child-process escape paths."""
from __future__ import annotations
import ctypes
import errno
import os
import runpy
import sys
from pathlib import Path
BLOCKED_AUDIT_PREFIXES = ("socket.", "subprocess.")
BLOCKED_AUDIT_EVENTS = {
"os.fork",
"os.forkpty",
"os.exec",
"os.posix_spawn",
"os.spawn",
"os.system",
}
WORKSPACE = Path(os.getenv("BIOEVAL_WORKSPACE", "/app")).resolve()
SYSTEM_READ_ROOTS = tuple(
Path(path).resolve()
for path in (
"/usr",
"/bin",
"/lib",
"/lib64",
"/etc",
sys.prefix,
sys.base_prefix,
)
if Path(path).exists()
)
SCMP_ACT_ALLOW = 0x7FFF0000
SCMP_ACT_ERRNO = 0x00050000
SCMP_CMP_MASKED_EQ = 7
CLONE_THREAD = 0x00010000
BLOCKED_SYSCALLS = (
"socket",
"socketpair",
"connect",
"bind",
"listen",
"accept",
"accept4",
"sendto",
"sendmsg",
"sendmmsg",
"recvfrom",
"recvmsg",
"recvmmsg",
"shutdown",
"fork",
"vfork",
"execve",
"execveat",
"ptrace",
"process_vm_readv",
"process_vm_writev",
"mount",
"umount2",
"pivot_root",
"chroot",
"setns",
"unshare",
"bpf",
"keyctl",
"add_key",
"request_key",
"userfaultfd",
)
class ScmpArgCmp(ctypes.Structure):
_fields_ = [
("arg", ctypes.c_uint),
("op", ctypes.c_uint),
("datum_a", ctypes.c_uint64),
("datum_b", ctypes.c_uint64),
]
def install_seccomp_filter() -> None:
"""Kernel-enforce no network, child process, namespace, or tracing syscalls."""
try:
seccomp = ctypes.CDLL("libseccomp.so.2", use_errno=True)
except OSError as exc:
raise RuntimeError("libseccomp is required for restricted Python") from exc
seccomp.seccomp_init.argtypes = [ctypes.c_uint32]
seccomp.seccomp_init.restype = ctypes.c_void_p
seccomp.seccomp_syscall_resolve_name.argtypes = [ctypes.c_char_p]
seccomp.seccomp_syscall_resolve_name.restype = ctypes.c_int
seccomp.seccomp_rule_add.argtypes = [
ctypes.c_void_p,
ctypes.c_uint32,
ctypes.c_int,
ctypes.c_uint,
]
seccomp.seccomp_rule_add.restype = ctypes.c_int
seccomp.seccomp_rule_add_array.argtypes = [
ctypes.c_void_p,
ctypes.c_uint32,
ctypes.c_int,
ctypes.c_uint,
ctypes.POINTER(ScmpArgCmp),
]
seccomp.seccomp_rule_add_array.restype = ctypes.c_int
seccomp.seccomp_load.argtypes = [ctypes.c_void_p]
seccomp.seccomp_load.restype = ctypes.c_int
seccomp.seccomp_release.argtypes = [ctypes.c_void_p]
context = seccomp.seccomp_init(SCMP_ACT_ALLOW)
if not context:
raise RuntimeError("could not initialize seccomp")
try:
deny = SCMP_ACT_ERRNO | errno.EPERM
for name in BLOCKED_SYSCALLS:
number = seccomp.seccomp_syscall_resolve_name(name.encode())
if number < 0:
continue
result = seccomp.seccomp_rule_add(context, deny, number, 0)
if result != 0:
raise OSError(-result, os.strerror(-result))
clone_number = seccomp.seccomp_syscall_resolve_name(b"clone")
if clone_number >= 0:
comparison = ScmpArgCmp(0, SCMP_CMP_MASKED_EQ, CLONE_THREAD, 0)
result = seccomp.seccomp_rule_add_array(
context, deny, clone_number, 1, ctypes.byref(comparison)
)
if result != 0:
raise OSError(-result, os.strerror(-result))
clone3_number = seccomp.seccomp_syscall_resolve_name(b"clone3")
if clone3_number >= 0:
result = seccomp.seccomp_rule_add(
context, SCMP_ACT_ERRNO | errno.ENOSYS, clone3_number, 0
)
if result != 0:
raise OSError(-result, os.strerror(-result))
result = seccomp.seccomp_load(context)
if result != 0:
raise OSError(-result, os.strerror(-result))
finally:
seccomp.seccomp_release(context)
def _inside(path: Path, root: Path) -> bool:
try:
path.relative_to(root)
return True
except ValueError:
return False
def _check_open(args: tuple[object, ...]) -> None:
if not args or isinstance(args[0], int):
return
path = Path(os.fspath(args[0]))
resolved = (Path.cwd() / path if not path.is_absolute() else path).resolve()
mode = args[1] if len(args) > 1 else None
flags = args[2] if len(args) > 2 and isinstance(args[2], int) else 0
write_requested = (
isinstance(mode, str) and any(marker in mode for marker in ("w", "a", "x", "+"))
) or flags & os.O_ACCMODE != os.O_RDONLY or bool(
flags & (os.O_CREAT | os.O_TRUNC | os.O_APPEND)
)
if write_requested:
if not _inside(resolved, WORKSPACE):
raise PermissionError("Analysis Python may only write inside /app.")
return
readable = _inside(resolved, WORKSPACE) or any(
_inside(resolved, root) for root in SYSTEM_READ_ROOTS
)
if resolved in {Path("/dev/null"), Path("/dev/urandom"), Path("/dev/random")}:
readable = True
if not readable:
raise PermissionError("Analysis Python may only read workspace and runtime files.")
def deny_unsafe_runtime(event: str, args: tuple[object, ...]) -> None:
if event == "open":
_check_open(args)
elif event in BLOCKED_AUDIT_EVENTS or event.startswith(BLOCKED_AUDIT_PREFIXES):
raise PermissionError(
"Network and child-process access are disabled in analysis Python; "
"use the guarded research tools."
)
def main(argv: list[str] | None = None) -> int:
args = list(sys.argv[1:] if argv is None else argv)
if not args:
raise SystemExit("restricted Python requires -c, -m, or a script path")
install_seccomp_filter()
sys.addaudithook(deny_unsafe_runtime)
if args[0] == "-c":
if len(args) < 2:
raise SystemExit("-c requires code")
sys.argv = ["-c", *args[2:]]
namespace = {"__name__": "__main__", "__file__": "<string>"}
exec(compile(args[1], "<string>", "exec"), namespace, namespace)
return 0
if args[0] == "-m":
if len(args) < 2:
raise SystemExit("-m requires a module")
sys.argv = [args[1], *args[2:]]
runpy.run_module(args[1], run_name="__main__", alter_sys=True)
return 0
sys.argv = [args[0], *args[1:]]
runpy.run_path(args[0], run_name="__main__")
return 0
if __name__ == "__main__":
raise SystemExit(main())
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