diff options
Diffstat (limited to 'cryptography/hazmat/bindings/openssl/backend.py')
| -rw-r--r-- | cryptography/hazmat/bindings/openssl/backend.py | 31 |
1 files changed, 30 insertions, 1 deletions
diff --git a/cryptography/hazmat/bindings/openssl/backend.py b/cryptography/hazmat/bindings/openssl/backend.py index db4d18e7..9f8ea939 100644 --- a/cryptography/hazmat/bindings/openssl/backend.py +++ b/cryptography/hazmat/bindings/openssl/backend.py @@ -193,6 +193,33 @@ class Backend(object): def create_symmetric_decryption_ctx(self, cipher, mode): return _CipherContext(self, cipher, mode, _CipherContext._DECRYPT) + def _handle_error(self): + code = self.lib.ERR_get_error() + assert code != 0 + lib = self.lib.ERR_GET_LIB(code) + func = self.lib.ERR_GET_FUNC(code) + reason = self.lib.ERR_GET_REASON(code) + return self._handle_error_code(lib, func, reason) + + def _handle_error_code(self, lib, func, reason): + if lib == self.lib.ERR_LIB_EVP: + if func == self.lib.EVP_F_EVP_ENCRYPTFINAL_EX: + if reason == self.lib.EVP_R_DATA_NOT_MULTIPLE_OF_BLOCK_LENGTH: + raise ValueError( + "The length of the provided data is not a multiple of " + "the block length" + ) + elif func == self.lib.EVP_F_EVP_DECRYPTFINAL_EX: + if reason == self.lib.EVP_R_DATA_NOT_MULTIPLE_OF_BLOCK_LENGTH: + raise ValueError( + "The length of the provided data is not a multiple of " + "the block length" + ) + + raise SystemError( + "Unknown error code from OpenSSL, you should probably file a bug." + ) + class GetCipherByName(object): def __init__(self, fmt): @@ -268,7 +295,9 @@ class _CipherContext(object): buf = self._backend.ffi.new("unsigned char[]", self._cipher.block_size) outlen = self._backend.ffi.new("int *") res = self._backend.lib.EVP_CipherFinal_ex(self._ctx, buf, outlen) - assert res != 0 + if res == 0: + self._backend._handle_error() + res = self._backend.lib.EVP_CIPHER_CTX_cleanup(self._ctx) assert res == 1 return self._backend.ffi.buffer(buf)[:outlen[0]] |