test_suite_pk: fix RSA issue in pk_psa_sign() when !PK_[PARSE|WRITE]_C are defined

This bug was not found until now because:
- !PK_[WRITE|PARSE]_C is only tested in component_full_no_pkparse_pkwrite()
- the test only case concerning RSA key had MBEDTLS_PK_WRITE_C as dependency
  so it was not executed in that component.

Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>

2 files changed, 27 insertions, 12 deletions

diff --git a/tests/suites/test_suite_pk.data b/tests/suites/test_suite_pk.data
index 102aee2..a979cbd 100644
--- a/tests/suites/test_suite_pk.data
+++ b/tests/suites/test_suite_pk.data
@@ -684,7 +684,7 @@ depends_on:MBEDTLS_PK_CAN_ECDSA_SIGN:MBEDTLS_ECP_HAVE_BP512R1
 pk_psa_sign:PSA_KEY_TYPE_ECC_KEY_PAIR(PSA_ECC_FAMILY_BRAINPOOL_P_R1):512
 
 PSA wrapped sign: RSA PKCS1 v1.5
-depends_on:MBEDTLS_RSA_C:MBEDTLS_PKCS1_V15:MBEDTLS_GENPRIME:MBEDTLS_PK_WRITE_C
+depends_on:MBEDTLS_RSA_C:MBEDTLS_PKCS1_V15:MBEDTLS_GENPRIME
 pk_psa_sign:PSA_KEY_TYPE_RSA_KEY_PAIR:1024
 
 PK sign ext: RSA2048, PK_RSA, MD_SHA256
diff --git a/tests/suites/test_suite_pk.function b/tests/suites/test_suite_pk.function
index 8f5e7f6..0a0f158 100644
--- a/tests/suites/test_suite_pk.function
+++ b/tests/suites/test_suite_pk.function
@@ -1875,12 +1875,21 @@ void pk_psa_sign(int psa_type, int bits)
             legacy_pub_key + sizeof(legacy_pub_key) - legacy_pub_key_len,
             legacy_pub_key_len);
 #else /* MBEDTLS_PK_WRITE_C */
-    ret = mbedtls_ecp_point_write_binary(&(mbedtls_pk_ec_ro(pk)->grp),
-                                         &(mbedtls_pk_ec_ro(pk)->Q),
-                                         MBEDTLS_ECP_PF_UNCOMPRESSED,
-                                         &legacy_pub_key_len, legacy_pub_key,
-                                         sizeof(legacy_pub_key));
-    TEST_EQUAL(ret, 0);
+    if (PSA_KEY_TYPE_IS_ECC_KEY_PAIR(psa_type)) {
+        TEST_EQUAL(mbedtls_ecp_point_write_binary(&(mbedtls_pk_ec_ro(pk)->grp),
+                                                  &(mbedtls_pk_ec_ro(pk)->Q),
+                                                  MBEDTLS_ECP_PF_UNCOMPRESSED,
+                                                  &legacy_pub_key_len, legacy_pub_key,
+                                                  sizeof(legacy_pub_key)), 0);
+    } else {
+        unsigned char *end = legacy_pub_key + sizeof(legacy_pub_key);
+        ret = mbedtls_rsa_write_pubkey(mbedtls_pk_rsa(pk), legacy_pub_key, &end);
+        legacy_pub_key_len = (size_t) ret;
+        TEST_ASSERT(legacy_pub_key_len > 0);
+        /* mbedtls_rsa_write_pubkey() writes data backward in the buffer so
+         * we shift that to the origin of the buffer instead. */
+        memmove(legacy_pub_key, end, legacy_pub_key_len);
+    }
 #endif /* MBEDTLS_PK_WRITE_C */
 
     /* Turn the PK context into an opaque one. */
@@ -1939,11 +1948,17 @@ void pk_psa_sign(int psa_type, int bits)
 #if defined(MBEDTLS_PK_WRITE_C) && defined(MBEDTLS_PK_PARSE_C)
     TEST_EQUAL(mbedtls_pk_parse_public_key(&pk, legacy_pub_key, legacy_pub_key_len), 0);
 #else
-    TEST_EQUAL(mbedtls_pk_setup(&pk, mbedtls_pk_info_from_type(MBEDTLS_PK_ECKEY)), 0);
-    TEST_EQUAL(mbedtls_ecp_group_load(&(mbedtls_pk_ec_rw(pk)->grp), ecp_grp_id), 0);
-    TEST_EQUAL(mbedtls_ecp_point_read_binary(&(mbedtls_pk_ec_ro(pk)->grp),
-                                             &(mbedtls_pk_ec_rw(pk)->Q),
-                                             legacy_pub_key, legacy_pub_key_len), 0);
+    if (PSA_KEY_TYPE_IS_ECC_KEY_PAIR(psa_type)) {
+        TEST_EQUAL(mbedtls_pk_setup(&pk, mbedtls_pk_info_from_type(MBEDTLS_PK_ECKEY)), 0);
+        TEST_EQUAL(mbedtls_ecp_group_load(&(mbedtls_pk_ec_rw(pk)->grp), ecp_grp_id), 0);
+        TEST_EQUAL(mbedtls_ecp_point_read_binary(&(mbedtls_pk_ec_ro(pk)->grp),
+                                                 &(mbedtls_pk_ec_rw(pk)->Q),
+                                                 legacy_pub_key, legacy_pub_key_len), 0);
+    } else {
+        TEST_EQUAL(mbedtls_pk_setup(&pk, mbedtls_pk_info_from_type(MBEDTLS_PK_RSA)), 0);
+        TEST_EQUAL(mbedtls_rsa_parse_pubkey(mbedtls_pk_rsa(pk), legacy_pub_key,
+                                            legacy_pub_key_len), 0);
+    }
 #endif
     TEST_ASSERT(mbedtls_pk_verify(&pk, MBEDTLS_MD_SHA256,
                                   hash, sizeof(hash), sig, sig_len) == 0);