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Dump libssl bindings in favour of the new optional cryptg module

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This commit is contained in:
Lonami Exo 2018-02-16 18:24:44 +01:00
parent c11aefa95b
commit 030f292203
2 changed files with 64 additions and 167 deletions
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20
telethon/crypto/aes.py
View File

@ -3,15 +3,14 @@ AES IGE implementation in Python. This module may use libssl if available.
"""
import os
import pyaes
from . import libssl
try:
import cryptg
except ImportError:
cryptg = None
if libssl.AES is not None:
# Use libssl if available, since it will be faster
AES = libssl.AES
else:
# Fallback to a pure Python implementation
class AES:
class AES:
"""
Class that servers as an interface to encrypt and decrypt
text through the AES IGE mode.
@ -22,6 +21,9 @@ else:
Decrypts the given text in 16-bytes blocks by using the
given key and 32-bytes initialization vector.
"""
if cryptg:
return cryptg.decrypt_ige(cipher_text, key, iv)
iv1 = iv[:len(iv) // 2]
iv2 = iv[len(iv) // 2:]
@ -54,12 +56,14 @@ else:
Encrypts the given text in 16-bytes blocks by using the
given key and 32-bytes initialization vector.
"""
# Add random padding iff it's not evenly divisible by 16 already
if len(plain_text) % 16 != 0:
padding_count = 16 - len(plain_text) % 16
plain_text += os.urandom(padding_count)
if cryptg:
return cryptg.encrypt_ige(plain_text, key, iv)
iv1 = iv[:len(iv) // 2]
iv2 = iv[len(iv) // 2:]

107
telethon/crypto/libssl.py
View File

@ -1,107 +0,0 @@
"""
This module holds an AES IGE class, if libssl is available on the system.
"""
import os
import ctypes
from ctypes.util import find_library
lib = find_library('ssl')
if not lib:
AES = None
else:
""" <aes.h>
# define AES_ENCRYPT 1
# define AES_DECRYPT 0
# define AES_MAXNR 14
struct aes_key_st {
# ifdef AES_LONG
unsigned long rd_key[4 * (AES_MAXNR + 1)];
# else
unsigned int rd_key[4 * (AES_MAXNR + 1)];
# endif
int rounds;
};
typedef struct aes_key_st AES_KEY;
int AES_set_encrypt_key(const unsigned char *userKey, const int bits,
AES_KEY *key);
int AES_set_decrypt_key(const unsigned char *userKey, const int bits,
AES_KEY *key);
void AES_ige_encrypt(const unsigned char *in, unsigned char *out,
size_t length, const AES_KEY *key,
unsigned char *ivec, const int enc);
"""
_libssl = ctypes.cdll.LoadLibrary(lib)
AES_MAXNR = 14
AES_ENCRYPT = ctypes.c_int(1)
AES_DECRYPT = ctypes.c_int(0)
class AES_KEY(ctypes.Structure):
"""Helper class representing an AES key"""
_fields_ = [
('rd_key', ctypes.c_uint32 * (4*(AES_MAXNR + 1))),
('rounds', ctypes.c_uint),
]
class AES:
"""
Class that servers as an interface to encrypt and decrypt
text through the AES IGE mode, using the system's libssl.
"""
@staticmethod
def decrypt_ige(cipher_text, key, iv):
"""
Decrypts the given text in 16-bytes blocks by using the
given key and 32-bytes initialization vector.
"""
aeskey = AES_KEY()
ckey = (ctypes.c_ubyte * len(key))(*key)
cklen = ctypes.c_int(len(key)*8)
cin = (ctypes.c_ubyte * len(cipher_text))(*cipher_text)
ctlen = ctypes.c_size_t(len(cipher_text))
cout = (ctypes.c_ubyte * len(cipher_text))()
civ = (ctypes.c_ubyte * len(iv))(*iv)
_libssl.AES_set_decrypt_key(ckey, cklen, ctypes.byref(aeskey))
_libssl.AES_ige_encrypt(
ctypes.byref(cin),
ctypes.byref(cout),
ctlen,
ctypes.byref(aeskey),
ctypes.byref(civ),
AES_DECRYPT
)
return bytes(cout)
@staticmethod
def encrypt_ige(plain_text, key, iv):
"""
Encrypts the given text in 16-bytes blocks by using the
given key and 32-bytes initialization vector.
"""
# Add random padding iff it's not evenly divisible by 16 already
if len(plain_text) % 16 != 0:
padding_count = 16 - len(plain_text) % 16
plain_text += os.urandom(padding_count)
aeskey = AES_KEY()
ckey = (ctypes.c_ubyte * len(key))(*key)
cklen = ctypes.c_int(len(key)*8)
cin = (ctypes.c_ubyte * len(plain_text))(*plain_text)
ctlen = ctypes.c_size_t(len(plain_text))
cout = (ctypes.c_ubyte * len(plain_text))()
civ = (ctypes.c_ubyte * len(iv))(*iv)
_libssl.AES_set_encrypt_key(ckey, cklen, ctypes.byref(aeskey))
_libssl.AES_ige_encrypt(
ctypes.byref(cin),
ctypes.byref(cout),
ctlen,
ctypes.byref(aeskey),
ctypes.byref(civ),
AES_ENCRYPT
)
return bytes(cout)