Fix PSA crypto inconsistencies in agreement+derivation
* #3741 Allow key agreement inside derivation with a key that's allowed
for the relevant agreement.
Signed-off-by: Steven Cooreman <steven.cooreman@silabs.com>
diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index 931e2e9..71a505c 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -1084,6 +1084,14 @@
return( ( policy_alg & ~PSA_ALG_HASH_MASK ) ==
( requested_alg & ~PSA_ALG_HASH_MASK ) );
}
+ /* If policy_alg is a generic key agreement operation, then using it for
+ * a key derivation with that key agreement is also compliant. */
+ if( PSA_ALG_IS_RAW_KEY_AGREEMENT( policy_alg ) &&
+ PSA_ALG_IS_KEY_AGREEMENT( requested_alg ) )
+ {
+ return( PSA_ALG_KEY_AGREEMENT_GET_BASE( requested_alg ) ==
+ policy_alg );
+ }
/* If it isn't permitted, it's forbidden. */
return( 0 );
}