Reject key agreement chained with PSA_ALG_TLS12_ECJPAKE_TO_PMS
The key derivation algorithm PSA_ALG_TLS12_ECJPAKE_TO_PMS cannot be
used on a shared secret from a key agreement since its input must be
an ECC public key. Reject this properly.
This is tested by test_suite_psa_crypto_op_fail.generated.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/ChangeLog.d/psa_alg_tls12_ecjpake_to_pms-reject_ka.txt b/ChangeLog.d/psa_alg_tls12_ecjpake_to_pms-reject_ka.txt
new file mode 100644
index 0000000..cfea661
--- /dev/null
+++ b/ChangeLog.d/psa_alg_tls12_ecjpake_to_pms-reject_ka.txt
@@ -0,0 +1,4 @@
+Bugfix
+ * The key derivation algorithm PSA_ALG_TLS12_ECJPAKE_TO_PMS cannot be
+ used on a shared secret from a key agreement since its input must be
+ an ECC public key. Reject this properly.
diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index 0a8949f..a683fdb 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -5168,6 +5168,18 @@
(void) alg;
return PSA_ERROR_NOT_SUPPORTED;
}
+
+static int psa_key_derivation_allows_free_form_secret_input(
+ psa_algorithm_t kdf_alg)
+{
+#if defined(PSA_WANT_ALG_TLS12_ECJPAKE_TO_PMS)
+ if (kdf_alg == PSA_ALG_TLS12_ECJPAKE_TO_PMS) {
+ return 0;
+ }
+#endif
+ (void) kdf_alg;
+ return 1;
+}
#endif /* AT_LEAST_ONE_BUILTIN_KDF */
psa_status_t psa_key_derivation_setup(psa_key_derivation_operation_t *operation,
@@ -5189,6 +5201,9 @@
if (status != PSA_SUCCESS) {
return status;
}
+ if (!psa_key_derivation_allows_free_form_secret_input(kdf_alg)) {
+ return PSA_ERROR_INVALID_ARGUMENT;
+ }
status = psa_key_derivation_setup_kdf(operation, kdf_alg);
#else
return PSA_ERROR_NOT_SUPPORTED;