Staging
v0.8.1
v0.8.1
Revision f9952b2083e2e122838d67c8061b3ddf69b25d8d authored by Thomas Wouters on 27 June 2001, 14:02:14 UTC, committed by Thomas Wouters on 27 June 2001, 14:02:14 UTC
SF bug 430991: wrong co_lnotab Armin Rigo pointed out that the way the line-# table got built didn't work for lines generating more than 255 bytes of bytecode. Fixed as he suggested, plus corresponding changes to pyassem.py, plus added some long overdue docs about this subtle table to compile.c.
1 parent 5829456
rexec.py
"""Restricted execution facilities.
The class RExec exports methods r_exec(), r_eval(), r_execfile(), and
r_import(), which correspond roughly to the built-in operations
exec, eval(), execfile() and import, but executing the code in an
environment that only exposes those built-in operations that are
deemed safe. To this end, a modest collection of 'fake' modules is
created which mimics the standard modules by the same names. It is a
policy decision which built-in modules and operations are made
available; this module provides a reasonable default, but derived
classes can change the policies e.g. by overriding or extending class
variables like ok_builtin_modules or methods like make_sys().
XXX To do:
- r_open should allow writing tmp dir
- r_exec etc. with explicit globals/locals? (Use rexec("exec ... in ...")?)
"""
import sys
import __builtin__
import os
import ihooks
__all__ = ["RExec"]
class FileBase:
ok_file_methods = ('fileno', 'flush', 'isatty', 'read', 'readline',
'readlines', 'seek', 'tell', 'write', 'writelines')
class FileWrapper(FileBase):
# XXX This is just like a Bastion -- should use that!
def __init__(self, f):
self.f = f
for m in self.ok_file_methods:
if not hasattr(self, m) and hasattr(f, m):
setattr(self, m, getattr(f, m))
def close(self):
self.flush()
TEMPLATE = """
def %s(self, *args):
return apply(getattr(self.mod, self.name).%s, args)
"""
class FileDelegate(FileBase):
def __init__(self, mod, name):
self.mod = mod
self.name = name
for m in FileBase.ok_file_methods + ('close',):
exec TEMPLATE % (m, m)
class RHooks(ihooks.Hooks):
def __init__(self, *args):
# Hacks to support both old and new interfaces:
# old interface was RHooks(rexec[, verbose])
# new interface is RHooks([verbose])
verbose = 0
rexec = None
if args and type(args[-1]) == type(0):
verbose = args[-1]
args = args[:-1]
if args and hasattr(args[0], '__class__'):
rexec = args[0]
args = args[1:]
if args:
raise TypeError, "too many arguments"
ihooks.Hooks.__init__(self, verbose)
self.rexec = rexec
def set_rexec(self, rexec):
# Called by RExec instance to complete initialization
self.rexec = rexec
def is_builtin(self, name):
return self.rexec.is_builtin(name)
def init_builtin(self, name):
m = __import__(name)
return self.rexec.copy_except(m, ())
def init_frozen(self, name): raise SystemError, "don't use this"
def load_source(self, *args): raise SystemError, "don't use this"
def load_compiled(self, *args): raise SystemError, "don't use this"
def load_package(self, *args): raise SystemError, "don't use this"
def load_dynamic(self, name, filename, file):
return self.rexec.load_dynamic(name, filename, file)
def add_module(self, name):
return self.rexec.add_module(name)
def modules_dict(self):
return self.rexec.modules
def default_path(self):
return self.rexec.modules['sys'].path
# XXX Backwards compatibility
RModuleLoader = ihooks.FancyModuleLoader
RModuleImporter = ihooks.ModuleImporter
class RExec(ihooks._Verbose):
"""Restricted Execution environment."""
ok_path = tuple(sys.path) # That's a policy decision
ok_builtin_modules = ('audioop', 'array', 'binascii',
'cmath', 'errno', 'imageop',
'marshal', 'math', 'md5', 'operator',
'parser', 'regex', 'pcre', 'rotor', 'select',
'strop', 'struct', 'time')
ok_posix_names = ('error', 'fstat', 'listdir', 'lstat', 'readlink',
'stat', 'times', 'uname', 'getpid', 'getppid',
'getcwd', 'getuid', 'getgid', 'geteuid', 'getegid')
ok_sys_names = ('ps1', 'ps2', 'copyright', 'version',
'platform', 'exit', 'maxint')
nok_builtin_names = ('open', 'reload', '__import__')
def __init__(self, hooks = None, verbose = 0):
ihooks._Verbose.__init__(self, verbose)
# XXX There's a circular reference here:
self.hooks = hooks or RHooks(verbose)
self.hooks.set_rexec(self)
self.modules = {}
self.ok_dynamic_modules = self.ok_builtin_modules
list = []
for mname in self.ok_builtin_modules:
if mname in sys.builtin_module_names:
list.append(mname)
self.ok_builtin_modules = tuple(list)
self.set_trusted_path()
self.make_builtin()
self.make_initial_modules()
# make_sys must be last because it adds the already created
# modules to its builtin_module_names
self.make_sys()
self.loader = RModuleLoader(self.hooks, verbose)
self.importer = RModuleImporter(self.loader, verbose)
# but since re isn't normally built-in, we can add it at the end;
# we need the imported to be set before this can be imported.
self.make_re()
def set_trusted_path(self):
# Set the path from which dynamic modules may be loaded.
# Those dynamic modules must also occur in ok_builtin_modules
self.trusted_path = filter(os.path.isabs, sys.path)
def load_dynamic(self, name, filename, file):
if name not in self.ok_dynamic_modules:
raise ImportError, "untrusted dynamic module: %s" % name
if sys.modules.has_key(name):
src = sys.modules[name]
else:
import imp
src = imp.load_dynamic(name, filename, file)
dst = self.copy_except(src, [])
return dst
def make_initial_modules(self):
self.make_main()
self.make_osname()
# Helpers for RHooks
def is_builtin(self, mname):
return mname in self.ok_builtin_modules
# The make_* methods create specific built-in modules
def make_builtin(self):
m = self.copy_except(__builtin__, self.nok_builtin_names)
m.__import__ = self.r_import
m.reload = self.r_reload
m.open = self.r_open
def make_main(self):
m = self.add_module('__main__')
def make_osname(self):
osname = os.name
src = __import__(osname)
dst = self.copy_only(src, self.ok_posix_names)
dst.environ = e = {}
for key, value in os.environ.items():
e[key] = value
def make_re(self):
dst = self.add_module("re")
src = self.r_import("pre")
for name in dir(src):
if name != "__name__":
setattr(dst, name, getattr(src, name))
def make_sys(self):
m = self.copy_only(sys, self.ok_sys_names)
m.modules = self.modules
m.argv = ['RESTRICTED']
m.path = map(None, self.ok_path)
m.exc_info = self.r_exc_info
m = self.modules['sys']
l = self.modules.keys() + list(self.ok_builtin_modules)
l.sort()
m.builtin_module_names = tuple(l)
# The copy_* methods copy existing modules with some changes
def copy_except(self, src, exceptions):
dst = self.copy_none(src)
for name in dir(src):
setattr(dst, name, getattr(src, name))
for name in exceptions:
try:
delattr(dst, name)
except AttributeError:
pass
return dst
def copy_only(self, src, names):
dst = self.copy_none(src)
for name in names:
try:
value = getattr(src, name)
except AttributeError:
continue
setattr(dst, name, value)
return dst
def copy_none(self, src):
m = self.add_module(src.__name__)
m.__doc__ = src.__doc__
return m
# Add a module -- return an existing module or create one
def add_module(self, mname):
if self.modules.has_key(mname):
return self.modules[mname]
self.modules[mname] = m = self.hooks.new_module(mname)
m.__builtins__ = self.modules['__builtin__']
return m
# The r* methods are public interfaces
def r_exec(self, code):
m = self.add_module('__main__')
exec code in m.__dict__
def r_eval(self, code):
m = self.add_module('__main__')
return eval(code, m.__dict__)
def r_execfile(self, file):
m = self.add_module('__main__')
return execfile(file, m.__dict__)
def r_import(self, mname, globals={}, locals={}, fromlist=[]):
return self.importer.import_module(mname, globals, locals, fromlist)
def r_reload(self, m):
return self.importer.reload(m)
def r_unload(self, m):
return self.importer.unload(m)
# The s_* methods are similar but also swap std{in,out,err}
def make_delegate_files(self):
s = self.modules['sys']
self.delegate_stdin = FileDelegate(s, 'stdin')
self.delegate_stdout = FileDelegate(s, 'stdout')
self.delegate_stderr = FileDelegate(s, 'stderr')
self.restricted_stdin = FileWrapper(sys.stdin)
self.restricted_stdout = FileWrapper(sys.stdout)
self.restricted_stderr = FileWrapper(sys.stderr)
def set_files(self):
if not hasattr(self, 'save_stdin'):
self.save_files()
if not hasattr(self, 'delegate_stdin'):
self.make_delegate_files()
s = self.modules['sys']
s.stdin = self.restricted_stdin
s.stdout = self.restricted_stdout
s.stderr = self.restricted_stderr
sys.stdin = self.delegate_stdin
sys.stdout = self.delegate_stdout
sys.stderr = self.delegate_stderr
def reset_files(self):
self.restore_files()
s = self.modules['sys']
self.restricted_stdin = s.stdin
self.restricted_stdout = s.stdout
self.restricted_stderr = s.stderr
def save_files(self):
self.save_stdin = sys.stdin
self.save_stdout = sys.stdout
self.save_stderr = sys.stderr
def restore_files(self):
sys.stdin = self.save_stdin
sys.stdout = self.save_stdout
sys.stderr = self.save_stderr
def s_apply(self, func, args=(), kw=None):
self.save_files()
try:
self.set_files()
if kw:
r = apply(func, args, kw)
else:
r = apply(func, args)
finally:
self.restore_files()
return r
def s_exec(self, *args):
return self.s_apply(self.r_exec, args)
def s_eval(self, *args):
return self.s_apply(self.r_eval, args)
def s_execfile(self, *args):
return self.s_apply(self.r_execfile, args)
def s_import(self, *args):
return self.s_apply(self.r_import, args)
def s_reload(self, *args):
return self.s_apply(self.r_reload, args)
def s_unload(self, *args):
return self.s_apply(self.r_unload, args)
# Restricted open(...)
def r_open(self, file, mode='r', buf=-1):
if mode not in ('r', 'rb'):
raise IOError, "can't open files for writing in restricted mode"
return open(file, mode, buf)
# Restricted version of sys.exc_info()
def r_exc_info(self):
ty, va, tr = sys.exc_info()
tr = None
return ty, va, tr
def test():
import sys, getopt, traceback
opts, args = getopt.getopt(sys.argv[1:], 'vt:')
verbose = 0
trusted = []
for o, a in opts:
if o == '-v':
verbose = verbose+1
if o == '-t':
trusted.append(a)
r = RExec(verbose=verbose)
if trusted:
r.ok_builtin_modules = r.ok_builtin_modules + tuple(trusted)
if args:
r.modules['sys'].argv = args
r.modules['sys'].path.insert(0, os.path.dirname(args[0]))
else:
r.modules['sys'].path.insert(0, "")
fp = sys.stdin
if args and args[0] != '-':
try:
fp = open(args[0])
except IOError, msg:
print "%s: can't open file %s" % (sys.argv[0], `args[0]`)
return 1
if fp.isatty():
print "*** RESTRICTED *** Python", sys.version
print sys.copyright
while 1:
try:
try:
s = raw_input('>>> ')
except EOFError:
print
break
if s and s[0] != '#':
s = s + '\n'
c = compile(s, '<stdin>', 'single')
r.s_exec(c)
except SystemExit, n:
return n
except:
traceback.print_exc()
else:
text = fp.read()
fp.close()
c = compile(text, fp.name, 'exec')
try:
r.s_exec(c)
except SystemExit, n:
return n
except:
traceback.print_exc()
return 1
if __name__ == '__main__':
sys.exit(test())
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