ctypescrypto/engine.py

   1 """
   2 engine loading and configuration
   3 """
   4 from ctypes import c_void_p, c_char_p, c_int
   5 from ctypescrypto import libcrypto,pyver
   6 from ctypescrypto.exception import LibCryptoError
   7
   8 __all__ = ['default', 'set_default', 'Engine']
   9
  10 default = None
  11
  12 class Engine(object):
  13     """
  14     Represents Openssl loadable module (engine).
  15     Allows to create PKey objects from private keys stored
  16     in the token, accessed by engine
  17     """
  18     def __init__(self, engine_id, **kwargs):
  19         if pyver > 2 or isinstance(engine_id, unicode):
  20             engine_id = engine_id.encode('utf-8')
  21         eng = libcrypto.ENGINE_by_id(engine_id)
  22         if eng is None:
  23             # Try load engine
  24             eng = libcrypto.ENGINE_by_id("dynamic")
  25             if  eng is None:
  26                 raise LibCryptoError("Cannot get 'dynamic' engine")
  27             if not libcrypto.ENGINE_ctrl_cmd_string(eng, "SO_PATH",
  28                                                     engine_id, 0):
  29                 raise LibCryptoError("Cannot execute ctrl cmd SO_PATH")
  30             if not libcrypto.ENGINE_ctrl_cmd_string(eng, "LOAD", None, 0):
  31                 raise LibCryptoError("Cannot execute ctrl cmd LOAD")
  32         if eng is None:
  33             raise ValueError("Cannot find engine " + engine)
  34         for cmd, value in kwargs.items():
  35             if not libcrypto.ENGINE_ctrl_cmd_string(eng, cmd, value, 0):
  36                 raise LibCryptoError("Cannot execute ctrl cmd %s" % cmd)
  37         if not libcrypto.ENGINE_init(eng):
  38             raise LibCryptoError("Cannot initialize engine")
  39         self.ptr = eng
  40
  41     def private_key(self, key_id, ui_method = None, ui_data=None):
  42         from ctypescrypto.pkey import PKey
  43         if ui_method is None:
  44             ui_ptr = libcrypto.UI_OpenSSL()
  45         else:
  46             ui_ptr = ui_method.ptr
  47         pkey = libcrypto.ENGINE_load_private_key(self.ptr, key_id, ui_ptr,
  48                                                  ui_data)
  49         if pkey is None:
  50             raise LibCryptoError("Cannot load private key")
  51         return PKey(ptr=pkey, cansign=True)
  52
  53 def set_default(eng, algorithms=0xFFFF):
  54     """
  55     Sets specified engine  as default for all
  56     algorithms, supported by it
  57
  58     For compatibility with 0.2.x if string is passed instead
  59     of engine, attempts to load engine with this id
  60     """
  61     if not isinstance(eng,Engine):
  62         eng=Engine(eng)
  63     global default
  64     libcrypto.ENGINE_set_default(eng.ptr, c_int(algorithms))
  65     default = eng
  66
  67 # Declare function result and arguments for used functions
  68 libcrypto.ENGINE_by_id.restype = c_void_p
  69 libcrypto.ENGINE_by_id.argtypes = (c_char_p, )
  70 libcrypto.ENGINE_set_default.argtypes = (c_void_p, c_int)
  71 libcrypto.ENGINE_ctrl_cmd_string.argtypes = (c_void_p, c_char_p, c_char_p,
  72                                              c_int)
  73 libcrypto.ENGINE_finish.argtypes = (c_char_p, )
  74 libcrypto.ENGINE_init.argtypes = (c_void_p, )
  75 libcrypto.UI_OpenSSL.restype = c_void_p
  76 libcrypto.ENGINE_load_private_key.argtypes = (c_void_p, c_char_p, c_void_p, c_void_p)
  77 libcrypto.ENGINE_load_private_key.restype = c_void_p