Refactoring: new method Algorithm.is_valid_for_operation
No intended behavior change.
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 1a03321..a56c863 100644
--- a/scripts/mbedtls_dev/crypto_knowledge.py
+++ b/scripts/mbedtls_dev/crypto_knowledge.py
@@ -214,9 +214,7 @@
This function does not currently handle key derivation or PAKE.
"""
#pylint: disable=too-many-branches,too-many-return-statements
- if alg.is_wildcard:
- return False
- if alg.is_invalid_truncation():
+ if not alg.is_valid_for_operation():
return False
if self.head == 'HMAC' and alg.head == 'HMAC':
return True
@@ -498,6 +496,19 @@
return True
return False
+ def is_valid_for_operation(self) -> bool:
+ """Whether this algorithm construction is valid for an operation.
+
+ This function assumes that the algorithm is constructed in a
+ "grammatically" correct way, and only rejects semantically invalid
+ combinations.
+ """
+ if self.is_wildcard:
+ return False
+ if self.is_invalid_truncation():
+ return False
+ return True
+
def can_do(self, category: AlgorithmCategory) -> bool:
"""Whether this algorithm can perform operations in the given category.
"""