pk: fix alg selection in mbedtls_pk_sign_ext() for opaque keys
This commit also fixes pk_psa_wrap_sign_ext() setting the RSA padding
mode so that mbedtls_pk_get_psa_attributes() correctly guesses
the PSA alg to be used.
Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>
diff --git a/library/pk.c b/library/pk.c
index 7aee940..8a5124f 100644
--- a/library/pk.c
+++ b/library/pk.c
@@ -1188,9 +1188,32 @@
}
if (mbedtls_pk_get_type(ctx) == MBEDTLS_PK_OPAQUE) {
+ psa_key_attributes_t key_attr = PSA_KEY_ATTRIBUTES_INIT;
+ psa_algorithm_t psa_alg, psa_enrollment_alg, sign_alg;
psa_status_t status;
- status = psa_sign_hash(ctx->priv_id, PSA_ALG_RSA_PSS(psa_md_alg),
+ status = psa_get_key_attributes(ctx->priv_id, &key_attr);
+ if (status != PSA_SUCCESS) {
+ return PSA_PK_RSA_TO_MBEDTLS_ERR(status);
+ }
+ psa_alg = psa_get_key_algorithm(&key_attr);
+ psa_enrollment_alg = psa_get_key_enrollment_algorithm(&key_attr);
+ psa_reset_key_attributes(&key_attr);
+
+ /* Since we're PK type is MBEDTLS_PK_RSASSA_PSS at least one between
+ * alg and enrollment alg should be of type RSA_PSS. */
+ if (PSA_ALG_IS_RSA_PSS(psa_alg)) {
+ sign_alg = psa_alg;
+ } else if (PSA_ALG_IS_RSA_PSS(psa_enrollment_alg)) {
+ sign_alg = psa_enrollment_alg;
+ } else {
+ /* The opaque key has no RSA PSS algorithm associated. */
+ return MBEDTLS_ERR_PK_BAD_INPUT_DATA;
+ }
+ /* Adjust the hashing algorithm. */
+ sign_alg = (sign_alg & ~PSA_ALG_HASH_MASK) | PSA_ALG_GET_HASH(psa_md_alg);
+
+ status = psa_sign_hash(ctx->priv_id, sign_alg,
hash, hash_len,
sig, sig_size, sig_len);
return PSA_PK_RSA_TO_MBEDTLS_ERR(status);
diff --git a/tests/suites/test_suite_pk.function b/tests/suites/test_suite_pk.function
index e1a0011..3d75ad0 100644
--- a/tests/suites/test_suite_pk.function
+++ b/tests/suites/test_suite_pk.function
@@ -1833,7 +1833,6 @@
unsigned char *pkey_start;
unsigned char hash[PSA_HASH_MAX_SIZE];
psa_algorithm_t psa_md_alg = mbedtls_md_psa_alg_from_type(md_alg);
- psa_algorithm_t psa_alg;
size_t hash_len = PSA_HASH_LENGTH(psa_md_alg);
void const *options = NULL;
mbedtls_pk_rsassa_pss_options rsassa_pss_options;
@@ -1850,6 +1849,10 @@
mbedtls_test_rnd_std_rand, NULL,
key_bits, 3), 0);
+ if (key_pk_type == MBEDTLS_PK_RSASSA_PSS) {
+ mbedtls_rsa_set_padding(mbedtls_pk_rsa(pk), MBEDTLS_RSA_PKCS_V21, MBEDTLS_MD_NONE);
+ }
+
/* Export underlying public key for re-importing in a legacy context. */
ret = mbedtls_pk_write_pubkey_der(&pk, pkey, sizeof(pkey));
TEST_ASSERT(ret >= 0);
@@ -1858,19 +1861,8 @@
/* mbedtls_pk_write_pubkey_der() writes backwards in the data buffer. */
pkey_start = pkey + sizeof(pkey) - pkey_len;
- if (key_pk_type == MBEDTLS_PK_RSA) {
- psa_alg = PSA_ALG_RSA_PKCS1V15_SIGN(psa_md_alg);
- } else if (key_pk_type == MBEDTLS_PK_RSASSA_PSS) {
- psa_alg = PSA_ALG_RSA_PSS(psa_md_alg);
- } else {
- TEST_ASSUME(!"PK key type not supported in this configuration");
- }
-
/* Turn PK context into an opaque one. */
TEST_EQUAL(mbedtls_pk_get_psa_attributes(&pk, PSA_KEY_USAGE_SIGN_HASH, &key_attr), 0);
- /* Tweak the algorithm associated with the PSA key because get_psa_attributes() returns
- * a PSA_ALG_RSA_PSS_ANY_SALT(), but mbedtls_pk_sign_ext() requires a PSA_ALG_RSA_PSS().*/
- psa_set_key_algorithm(&key_attr, psa_alg);
TEST_EQUAL(mbedtls_pk_import_into_psa(&pk, &key_attr, &key_id), 0);
mbedtls_pk_free(&pk);
mbedtls_pk_init(&pk);