shell bypass 403
"""
magic is a wrapper around the libmagic file identification library.
See README for more information.
Usage:
>>> import magic
>>> magic.from_file("testdata/test.pdf")
'PDF document, version 1.2'
>>> magic.from_file("testdata/test.pdf", mime=True)
'application/pdf'
>>> magic.from_buffer(open("testdata/test.pdf").read(1024))
'PDF document, version 1.2'
>>>
"""
import sys
import glob
import os.path
import ctypes
import ctypes.util
import threading
from ctypes import c_char_p, c_int, c_size_t, c_void_p
class MagicException(Exception):
def __init__(self, message):
super(MagicException, self).__init__(message)
self.message = message
class Magic:
"""
Magic is a wrapper around the libmagic C library.
"""
def __init__(self, mime=False, magic_file=None, mime_encoding=False,
keep_going=False, uncompress=False):
"""
Create a new libmagic wrapper.
mime - if True, mimetypes are returned instead of textual descriptions
mime_encoding - if True, codec is returned
magic_file - use a mime database other than the system default
keep_going - don't stop at the first match, keep going
uncompress - Try to look inside compressed files.
"""
self.flags = MAGIC_NONE
if mime:
self.flags |= MAGIC_MIME
if mime_encoding:
self.flags |= MAGIC_MIME_ENCODING
if keep_going:
self.flags |= MAGIC_CONTINUE
if uncompress:
self.flags |= MAGIC_COMPRESS
self.cookie = magic_open(self.flags)
self.lock = threading.Lock()
magic_load(self.cookie, magic_file)
def from_buffer(self, buf):
"""
Identify the contents of `buf`
"""
with self.lock:
try:
return maybe_decode(magic_buffer(self.cookie, buf))
except MagicException as e:
return self._handle509Bug(e)
def from_file(self, filename):
# raise FileNotFoundException or IOError if the file does not exist
with open(filename):
pass
with self.lock:
try:
return maybe_decode(magic_file(self.cookie, filename))
except MagicException as e:
return self._handle509Bug(e)
def _handle509Bug(self, e):
# libmagic 5.09 has a bug where it might fail to identify the
# mimetype of a file and returns null from magic_file (and
# likely _buffer), but also does not return an error message.
if e.message is None and (self.flags & MAGIC_MIME):
return "application/octet-stream"
else:
raise e
def __del__(self):
# no _thread_check here because there can be no other
# references to this object at this point.
# during shutdown magic_close may have been cleared already so
# make sure it exists before using it.
# the self.cookie check should be unnecessary and was an
# incorrect fix for a threading problem, however I'm leaving
# it in because it's harmless and I'm slightly afraid to
# remove it.
if self.cookie and magic_close:
magic_close(self.cookie)
self.cookie = None
_instances = {}
def _get_magic_type(mime):
i = _instances.get(mime)
if i is None:
i = _instances[mime] = Magic(mime=mime)
return i
def from_file(filename, mime=False):
""""
Accepts a filename and returns the detected filetype. Return
value is the mimetype if mime=True, otherwise a human readable
name.
>>> magic.from_file("testdata/test.pdf", mime=True)
'application/pdf'
"""
m = _get_magic_type(mime)
return m.from_file(filename)
def from_buffer(buffer, mime=False):
"""
Accepts a binary string and returns the detected filetype. Return
value is the mimetype if mime=True, otherwise a human readable
name.
>>> magic.from_buffer(open("testdata/test.pdf").read(1024))
'PDF document, version 1.2'
"""
m = _get_magic_type(mime)
return m.from_buffer(buffer)
libmagic = None
# Let's try to find magic or magic1
dll = ctypes.util.find_library('magic') or ctypes.util.find_library('magic1') or ctypes.util.find_library('cygmagic-1')
# This is necessary because find_library returns None if it doesn't find the library
if dll:
libmagic = ctypes.CDLL(dll)
if not libmagic or not libmagic._name:
windows_dlls = ['magic1.dll','cygmagic-1.dll']
platform_to_lib = {'darwin': ['/opt/local/lib/libmagic.dylib',
'/usr/local/lib/libmagic.dylib'] +
# Assumes there will only be one version installed
glob.glob('/usr/local/Cellar/libmagic/*/lib/libmagic.dylib'),
'win32': windows_dlls,
'cygwin': windows_dlls,
'linux': ['libmagic.so.1'], # fallback for some Linuxes (e.g. Alpine) where library search does not work
}
platform = 'linux' if sys.platform.startswith('linux') else sys.platform
for dll in platform_to_lib.get(platform, []):
try:
libmagic = ctypes.CDLL(dll)
break
except OSError:
pass
if not libmagic or not libmagic._name:
# It is better to raise an ImportError since we are importing magic module
raise ImportError('failed to find libmagic. Check your installation')
magic_t = ctypes.c_void_p
def errorcheck_null(result, func, args):
if result is None:
err = magic_error(args[0])
raise MagicException(err)
else:
return result
def errorcheck_negative_one(result, func, args):
if result is -1:
err = magic_error(args[0])
raise MagicException(err)
else:
return result
# return str on python3. Don't want to unconditionally
# decode because that results in unicode on python2
def maybe_decode(s):
if str == bytes:
return s
else:
return s.decode('utf-8')
def coerce_filename(filename):
if filename is None:
return None
# ctypes will implicitly convert unicode strings to bytes with
# .encode('ascii'). If you use the filesystem encoding
# then you'll get inconsistent behavior (crashes) depending on the user's
# LANG environment variable
is_unicode = (sys.version_info[0] <= 2 and
isinstance(filename, unicode)) or \
(sys.version_info[0] >= 3 and
isinstance(filename, str))
if is_unicode:
return filename.encode('utf-8')
else:
return filename
magic_open = libmagic.magic_open
magic_open.restype = magic_t
magic_open.argtypes = [c_int]
magic_close = libmagic.magic_close
magic_close.restype = None
magic_close.argtypes = [magic_t]
magic_error = libmagic.magic_error
magic_error.restype = c_char_p
magic_error.argtypes = [magic_t]
magic_errno = libmagic.magic_errno
magic_errno.restype = c_int
magic_errno.argtypes = [magic_t]
_magic_file = libmagic.magic_file
_magic_file.restype = c_char_p
_magic_file.argtypes = [magic_t, c_char_p]
_magic_file.errcheck = errorcheck_null
def magic_file(cookie, filename):
return _magic_file(cookie, coerce_filename(filename))
_magic_buffer = libmagic.magic_buffer
_magic_buffer.restype = c_char_p
_magic_buffer.argtypes = [magic_t, c_void_p, c_size_t]
_magic_buffer.errcheck = errorcheck_null
def magic_buffer(cookie, buf):
return _magic_buffer(cookie, buf, len(buf))
_magic_load = libmagic.magic_load
_magic_load.restype = c_int
_magic_load.argtypes = [magic_t, c_char_p]
_magic_load.errcheck = errorcheck_negative_one
def magic_load(cookie, filename):
return _magic_load(cookie, coerce_filename(filename))
magic_setflags = libmagic.magic_setflags
magic_setflags.restype = c_int
magic_setflags.argtypes = [magic_t, c_int]
magic_check = libmagic.magic_check
magic_check.restype = c_int
magic_check.argtypes = [magic_t, c_char_p]
magic_compile = libmagic.magic_compile
magic_compile.restype = c_int
magic_compile.argtypes = [magic_t, c_char_p]
MAGIC_NONE = 0x000000 # No flags
MAGIC_DEBUG = 0x000001 # Turn on debugging
MAGIC_SYMLINK = 0x000002 # Follow symlinks
MAGIC_COMPRESS = 0x000004 # Check inside compressed files
MAGIC_DEVICES = 0x000008 # Look at the contents of devices
MAGIC_MIME = 0x000010 # Return a mime string
MAGIC_MIME_ENCODING = 0x000400 # Return the MIME encoding
MAGIC_CONTINUE = 0x000020 # Return all matches
MAGIC_CHECK = 0x000040 # Print warnings to stderr
MAGIC_PRESERVE_ATIME = 0x000080 # Restore access time on exit
MAGIC_RAW = 0x000100 # Don't translate unprintable chars
MAGIC_ERROR = 0x000200 # Handle ENOENT etc as real errors
MAGIC_NO_CHECK_COMPRESS = 0x001000 # Don't check for compressed files
MAGIC_NO_CHECK_TAR = 0x002000 # Don't check for tar files
MAGIC_NO_CHECK_SOFT = 0x004000 # Don't check magic entries
MAGIC_NO_CHECK_APPTYPE = 0x008000 # Don't check application type
MAGIC_NO_CHECK_ELF = 0x010000 # Don't check for elf details
MAGIC_NO_CHECK_ASCII = 0x020000 # Don't check for ascii files
MAGIC_NO_CHECK_TROFF = 0x040000 # Don't check ascii/troff
MAGIC_NO_CHECK_FORTRAN = 0x080000 # Don't check ascii/fortran
MAGIC_NO_CHECK_TOKENS = 0x100000 # Don't check ascii/tokens