64-bit block ciphers are incompatible with some modes
Only allow selected modes with 64-bit block ciphers (i.e. DES).
This removes some storage tests and creates corresponding op_fail tests.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/scripts/mbedtls_dev/crypto_knowledge.py b/scripts/mbedtls_dev/crypto_knowledge.py
index 6f49940..bd4d94e 100644
--- a/scripts/mbedtls_dev/crypto_knowledge.py
+++ b/scripts/mbedtls_dev/crypto_knowledge.py
@@ -218,6 +218,12 @@
return False
if self.head == 'HMAC' and alg.head == 'HMAC':
return True
+ if self.head == 'DES':
+ # 64-bit block ciphers only allow a reduced set of modes.
+ return alg.head in [
+ 'CBC_NO_PADDING', 'CBC_PKCS7',
+ 'ECB_NO_PADDING',
+ ]
if self.head in BLOCK_CIPHERS and \
alg.head in frozenset.union(BLOCK_MAC_MODES,
BLOCK_CIPHER_MODES,