X-Git-Url: https://wagner.pp.ru/gitweb/?a=blobdiff_plain;f=ctypescrypto%2Fcipher.py;h=c2053e988354574d299e0bd1c36e6cf98c7ff701;hb=911a7fb801bfd74cb50b08fa77ae5c50d1890d8d;hp=1ea4f797d7f4d87e88e86832ae438651d18dde68;hpb=8afcf4f352ef2f967adbe84837d4abc5e9b6ee0c;p=oss%2Fctypescrypto.git

diff --git a/ctypescrypto/cipher.py b/ctypescrypto/cipher.py
index 1ea4f79..c2053e9 100644
--- a/ctypescrypto/cipher.py
+++ b/ctypescrypto/cipher.py
@@ -1,3 +1,7 @@
+"""
+access to symmetric ciphers from libcrypto
+
+"""
 from ctypes import create_string_buffer,c_char_p,c_void_p,c_int,c_long,byref,POINTER
 from ctypescrypto import libcrypto
 from ctypescrypto.exception import LibCryptoError
@@ -101,6 +105,10 @@ class Cipher:
 
 		"""
 		self._clean_ctx()
+		# Check key and iv length
+		if key is None:
+			raise ValueError("No key specified")
+
 		key_ptr = c_char_p(key)
 		iv_ptr = c_char_p(iv)
 		self.ctx = libcrypto.EVP_CIPHER_CTX_new()
@@ -111,7 +119,22 @@ class Cipher:
 			enc = 1
 		else: 
 			enc = 0
-		result = libcrypto.EVP_CipherInit_ex(self.ctx, cipher_type.cipher, None, key_ptr, iv_ptr, c_int(enc))
+		if not iv is None and len(iv) != cipher_type.iv_length():
+			raise ValueError("Invalid IV length for this algorithm")
+			
+		if len(key) != cipher_type.key_length():
+			if (cipher_type.flags() & 8) != 0:
+				# Variable key length cipher.
+				result = libcrypto.EVP_CipherInit_ex(self.ctx, cipher_type.cipher, None, None, None, c_int(enc))
+				result=libcrypto.EVP_CIPHER_CTX_set_key_length(self.ctx,len(key))
+				if result == 0:
+					self._clean_ctx()
+					raise CipherError("Unable to set key length")
+				result = libcrypto.EVP_CipherInit_ex(self.ctx, None, None, key_ptr, iv_ptr, c_int(enc))
+			else:
+				raise ValueError("Invalid key length for this algorithm")
+		else:
+			result = libcrypto.EVP_CipherInit_ex(self.ctx, cipher_type.cipher, None, key_ptr, iv_ptr, c_int(enc))
 		if result == 0:
 			self._clean_ctx()
 			raise CipherError, "Unable to initialize cipher"
@@ -170,7 +193,7 @@ class Cipher:
 			raise CipherError, "Cipher operation is already completed"
 		outbuf=create_string_buffer(self.block_size)
 		self.cipher_finalized = True
-		outlen=c_int()
+		outlen=c_int(0)
 		result = libcrypto.EVP_CipherFinal_ex(self.ctx,outbuf , byref(outlen))
 		if result == 0:
 			self._clean_ctx()
@@ -208,4 +231,4 @@ libcrypto.EVP_CIPHER_nid.argtypes=(c_void_p,)
 libcrypto.EVP_CipherUpdate.argtypes=(c_void_p,c_char_p,POINTER(c_int),c_char_p,c_int)
 libcrypto.EVP_get_cipherbyname.restype=c_void_p
 libcrypto.EVP_get_cipherbyname.argtypes=(c_char_p,)
-
+libcrypto.EVP_CIPHER_CTX_set_key_length.argtypes=(c_void_p,c_int)