Merge pull request #141 from reaperhulk/block-cipher-buffer-sizing
Fix Block cipher buffer sizing
diff --git a/cryptography/bindings/openssl/api.py b/cryptography/bindings/openssl/api.py
index 35be19c..3c2cf2e 100644
--- a/cryptography/bindings/openssl/api.py
+++ b/cryptography/bindings/openssl/api.py
@@ -128,7 +128,8 @@
return ctx
def update_encrypt_context(self, ctx, plaintext):
- buf = self.ffi.new("unsigned char[]", len(plaintext))
+ block_size = self.lib.EVP_CIPHER_CTX_block_size(ctx)
+ buf = self.ffi.new("unsigned char[]", len(plaintext) + block_size - 1)
outlen = self.ffi.new("int *")
res = self.lib.EVP_EncryptUpdate(
ctx, buf, outlen, plaintext, len(plaintext)
@@ -137,8 +138,7 @@
return self.ffi.buffer(buf)[:outlen[0]]
def finalize_encrypt_context(self, ctx):
- cipher = self.lib.EVP_CIPHER_CTX_cipher(ctx)
- block_size = self.lib.EVP_CIPHER_block_size(cipher)
+ block_size = self.lib.EVP_CIPHER_CTX_block_size(ctx)
buf = self.ffi.new("unsigned char[]", block_size)
outlen = self.ffi.new("int *")
res = self.lib.EVP_EncryptFinal_ex(ctx, buf, outlen)
diff --git a/cryptography/bindings/openssl/evp.py b/cryptography/bindings/openssl/evp.py
index 2b7b0f4..2015990 100644
--- a/cryptography/bindings/openssl/evp.py
+++ b/cryptography/bindings/openssl/evp.py
@@ -76,4 +76,5 @@
MACROS = """
int EVP_PKEY_assign_RSA(EVP_PKEY *, RSA *);
int EVP_PKEY_assign_DSA(EVP_PKEY *, DSA *);
+int EVP_CIPHER_CTX_block_size(const EVP_CIPHER_CTX *);
"""
diff --git a/tests/primitives/test_block.py b/tests/primitives/test_block.py
index f4d3f46..9f5905b 100644
--- a/tests/primitives/test_block.py
+++ b/tests/primitives/test_block.py
@@ -63,3 +63,14 @@
with pytest.raises(ValueError):
cipher.finalize()
+
+ def test_unaligned_block_encryption(self, api):
+ cipher = BlockCipher(
+ ciphers.AES(binascii.unhexlify(b"0" * 32)),
+ modes.ECB(),
+ api
+ )
+ ct = cipher.encrypt(b"a" * 15)
+ assert ct == b""
+ ct += cipher.encrypt(b"a" * 65)
+ assert len(ct) == 80