commit 275ecde2ca91074a2d308af91c041c0c6d312a52
author Gilles Peskine <Gilles.Peskine@arm.com> Sat Mar 19 11:15:41 2022 +0100
committer Gilles Peskine <Gilles.Peskine@arm.com> Fri Apr 15 16:15:48 2022 +0200
tree 65b1a8b43e67184d2b321ecac23f2ab76ad3d287
parent 743972cd56fd1a3051e2b821bcd9269157011aa4

exercise_key: signature: detect function/algorithm incompatibility

Don't try to use {sign,verify}_message on algorithms that only support
{sign_verify}_hash. Normally exercise_key() tries all usage that is
supported by policy, however PSA_KEY_USAGE_{SIGN,VERIFY}_MESSAGE is implied
by PSA_KEY_USAGE_{SIGN,VERIFY}_HASH so it's impossible for the test data to
omit the _MESSAGE policies with hash-only algorithms.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>

tests/src/psa_exercise_key.c

diff --git a/tests/src/psa_exercise_key.c b/tests/src/psa_exercise_key.c
index 8a2207c..db3651d 100644
--- a/tests/src/psa_exercise_key.c
+++ b/tests/src/psa_exercise_key.c
@@ -293,6 +293,17 @@
     return( 0 );
 }
 
+static int can_sign_or_verify_message( psa_key_usage_t usage,
+                                       psa_algorithm_t alg )
+{
+    /* Sign-the-unspecified-hash algorithms can only be used with
+     * {sign,verify}_hash, not with {sign,verify}_message. */
+    if( alg == PSA_ALG_ECDSA_ANY || alg == PSA_ALG_RSA_PKCS1V15_SIGN_RAW )
+        return( 0 );
+    return( usage & ( PSA_KEY_USAGE_SIGN_MESSAGE |
+                      PSA_KEY_USAGE_VERIFY_MESSAGE ) );
+}
+
 static int exercise_signature_key( mbedtls_svc_key_id_t key,
                                    psa_key_usage_t usage,
                                    psa_algorithm_t alg )
@@ -343,7 +354,7 @@
         }
     }
 
-    if( usage & ( PSA_KEY_USAGE_SIGN_MESSAGE | PSA_KEY_USAGE_VERIFY_MESSAGE ) )
+    if( can_sign_or_verify_message( usage, alg ) )
     {
         unsigned char message[256] = "Hello, world...";
         unsigned char signature[PSA_SIGNATURE_MAX_SIZE] = {0};