Document and check the consistency of truncated MAC encodings
Add comments noting that the maximum length of a MAC must fit in
PSA_ALG_MAC_TRUNCATION_MASK. Add a unit test that verifies that the
maximum MAC size fits.
diff --git a/include/psa/crypto_sizes.h b/include/psa/crypto_sizes.h
index 169566e..b5ff2aa 100644
--- a/include/psa/crypto_sizes.h
+++ b/include/psa/crypto_sizes.h
@@ -79,6 +79,9 @@
*/
/* All non-HMAC MACs have a maximum size that's smaller than the
* minimum possible value of PSA_HASH_MAX_SIZE in this implementation. */
+/* Note that the encoding of truncated MAC algorithms limits this value
+ * to 64 bytes.
+ */
#define PSA_MAC_MAX_SIZE PSA_HASH_MAX_SIZE
/* The maximum size of an RSA key on this implementation, in bits.