pk: update pkparse and pkwrite to use the new public key storing solution
Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>
diff --git a/library/pkparse.c b/library/pkparse.c
index 87b707d..d47b099 100644
--- a/library/pkparse.c
+++ b/library/pkparse.c
@@ -37,6 +37,9 @@
#if defined(MBEDTLS_RSA_C) || defined(MBEDTLS_ECP_C)
#include "pkwrite.h"
#endif
+#if defined(MBEDTLS_ECP_LIGHT)
+#include "pk_internal.h"
+#endif
#if defined(MBEDTLS_ECDSA_C)
#include "mbedtls/ecdsa.h"
#endif
@@ -455,6 +458,29 @@
}
#endif /* MBEDTLS_PK_PARSE_EC_EXTENDED */
+#if defined(MBEDTLS_PK_USE_PSA_EC_DATA)
+/* Functions pk_use_ecparams() and pk_use_ecparams_rfc8410() update the
+ * ecp_keypair structure with proper group ID. The purpose of this helper
+ * function is to update ec_family and ec_bits accordingly. */
+static int pk_update_psa_ecparams(mbedtls_pk_context *pk,
+ mbedtls_ecp_group_id grp_id)
+{
+ psa_ecc_family_t ec_family;
+ size_t bits;
+
+ ec_family = mbedtls_ecc_group_to_psa(grp_id, &bits);
+
+ if ((pk->ec_family != 0) && (pk->ec_family != ec_family)) {
+ return MBEDTLS_ERR_PK_KEY_INVALID_FORMAT;
+ }
+
+ pk->ec_family = ec_family;
+ pk->ec_bits = bits;
+
+ return 0;
+}
+#endif /* MBEDTLS_PK_USE_PSA_EC_DATA */
+
/*
* Use EC parameters to initialise an EC group
*
@@ -463,7 +489,7 @@
* specifiedCurve SpecifiedECDomain -- = SEQUENCE { ... }
* -- implicitCurve NULL
*/
-static int pk_use_ecparams(const mbedtls_asn1_buf *params, mbedtls_ecp_group *grp)
+static int pk_use_ecparams(const mbedtls_asn1_buf *params, mbedtls_pk_context *pk)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
mbedtls_ecp_group_id grp_id;
@@ -482,39 +508,41 @@
#endif
}
- /*
- * grp may already be initialized; if so, make sure IDs match
- */
- if (grp->id != MBEDTLS_ECP_DP_NONE && grp->id != grp_id) {
+ /* grp may already be initialized; if so, make sure IDs match */
+ if (mbedtls_pk_ec_ro(*pk)->grp.id != MBEDTLS_ECP_DP_NONE &&
+ mbedtls_pk_ec_ro(*pk)->grp.id != grp_id) {
return MBEDTLS_ERR_PK_KEY_INVALID_FORMAT;
}
- if ((ret = mbedtls_ecp_group_load(grp, grp_id)) != 0) {
+ if ((ret = mbedtls_ecp_group_load(&(mbedtls_pk_ec_rw(*pk)->grp),
+ grp_id)) != 0) {
return ret;
}
+#if defined(MBEDTLS_PK_USE_PSA_EC_DATA)
+ ret = pk_update_psa_ecparams(pk, grp_id);
+#endif /* MBEDTLS_PK_USE_PSA_EC_DATA */
- return 0;
+ return ret;
}
-#if defined(MBEDTLS_ECP_LIGHT)
/*
* Helper function for deriving a public key from its private counterpart.
*/
-static int pk_derive_public_key(mbedtls_ecp_keypair *eck,
+static int pk_derive_public_key(mbedtls_pk_context *pk,
const unsigned char *d, size_t d_len,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng)
{
int ret;
+ mbedtls_ecp_keypair *eck = (mbedtls_ecp_keypair *) pk->pk_ctx;
#if defined(MBEDTLS_USE_PSA_CRYPTO)
psa_status_t status, destruction_status;
psa_key_attributes_t key_attr = PSA_KEY_ATTRIBUTES_INIT;
size_t curve_bits;
psa_ecc_family_t curve = mbedtls_ecc_group_to_psa(eck->grp.id, &curve_bits);
- /* This buffer is used to store the private key at first and then the
- * public one (but not at the same time). Therefore we size it for the
- * latter since it's bigger. */
+#if !defined(MBEDTLS_PK_USE_PSA_EC_DATA)
unsigned char key_buf[MBEDTLS_PSA_MAX_EC_PUBKEY_LENGTH];
size_t key_len;
+#endif /* !MBEDTLS_PK_USE_PSA_EC_DATA */
mbedtls_svc_key_id_t key_id = MBEDTLS_SVC_KEY_ID_INIT;
(void) f_rng;
@@ -529,9 +557,12 @@
return ret;
}
- mbedtls_platform_zeroize(key_buf, sizeof(key_buf));
-
+#if defined(MBEDTLS_PK_USE_PSA_EC_DATA)
+ status = psa_export_public_key(key_id, pk->pub_raw, sizeof(pk->pub_raw),
+ &pk->pub_raw_len);
+#else /* MBEDTLS_PK_USE_PSA_EC_DATA */
status = psa_export_public_key(key_id, key_buf, sizeof(key_buf), &key_len);
+#endif /* MBEDTLS_PK_USE_PSA_EC_DATA */
ret = psa_pk_status_to_mbedtls(status);
destruction_status = psa_destroy_key(key_id);
if (ret != 0) {
@@ -539,8 +570,9 @@
} else if (destruction_status != PSA_SUCCESS) {
return psa_pk_status_to_mbedtls(destruction_status);
}
-
+#if !defined(MBEDTLS_PK_USE_PSA_EC_DATA)
ret = mbedtls_ecp_point_read_binary(&eck->grp, &eck->Q, key_buf, key_len);
+#endif /* !MBEDTLS_PK_USE_PSA_EC_DATA */
#else /* MBEDTLS_USE_PSA_CRYPTO */
(void) d;
(void) d_len;
@@ -557,13 +589,24 @@
*/
static int pk_use_ecparams_rfc8410(const mbedtls_asn1_buf *params,
mbedtls_ecp_group_id grp_id,
- mbedtls_ecp_group *grp)
+ mbedtls_pk_context *pk)
{
+ mbedtls_ecp_keypair *ecp = mbedtls_pk_ec_rw(*pk);
+ int ret;
+
if (params->tag != 0 || params->len != 0) {
return MBEDTLS_ERR_PK_KEY_INVALID_FORMAT;
}
- return mbedtls_ecp_group_load(grp, grp_id);
+ ret = mbedtls_ecp_group_load(&(ecp->grp), grp_id);
+ if (ret != 0) {
+ return ret;
+ }
+
+#if defined(MBEDTLS_PK_USE_PSA_EC_DATA)
+ ret = pk_update_psa_ecparams(pk, grp_id);
+#endif /* MBEDTLS_PK_USE_PSA_EC_DATA */
+ return ret;
}
/*
@@ -571,10 +614,11 @@
*
* CurvePrivateKey ::= OCTET STRING
*/
-static int pk_parse_key_rfc8410_der(mbedtls_ecp_keypair *eck,
+static int pk_parse_key_rfc8410_der(mbedtls_pk_context *pk,
unsigned char *key, size_t keylen, const unsigned char *end,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng)
{
+ mbedtls_ecp_keypair *eck = mbedtls_pk_ec_rw(*pk);
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t len;
@@ -591,10 +635,10 @@
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
}
- // pk_parse_key_pkcs8_unencrypted_der() only supports version 1 PKCS8 keys,
- // which never contain a public key. As such, derive the public key
- // unconditionally.
- if ((ret = pk_derive_public_key(eck, key, len, f_rng, p_rng)) != 0) {
+ /* pk_parse_key_pkcs8_unencrypted_der() only supports version 1 PKCS8 keys,
+ * which never contain a public key. As such, derive the public key
+ * unconditionally. */
+ if ((ret = pk_derive_public_key(pk, key, len, f_rng, p_rng)) != 0) {
mbedtls_ecp_keypair_free(eck);
return ret;
}
@@ -607,7 +651,42 @@
return 0;
}
#endif /* MBEDTLS_PK_HAVE_RFC8410_CURVES */
-#endif /* MBEDTLS_ECP_LIGHT */
+
+#if defined(MBEDTLS_PK_USE_PSA_EC_DATA)
+/*
+ * Create a temporary ecp_keypair for converting an EC point in compressed
+ * format to an uncompressed one
+ */
+static int pk_convert_compressed_ec(mbedtls_pk_context *pk,
+ const unsigned char *in_start, size_t in_len,
+ size_t *out_buf_len, unsigned char *out_buf,
+ size_t out_buf_size)
+{
+ mbedtls_ecp_keypair ecp_key;
+ mbedtls_ecp_group_id ecp_group_id;
+ int ret;
+
+ ecp_group_id = mbedtls_ecc_group_of_psa(pk->ec_family, pk->ec_bits, 0);
+
+ mbedtls_ecp_keypair_init(&ecp_key);
+ ret = mbedtls_ecp_group_load(&(ecp_key.grp), ecp_group_id);
+ if (ret != 0) {
+ return ret;
+ }
+ ret = mbedtls_ecp_point_read_binary(&(ecp_key.grp), &ecp_key.Q,
+ in_start, in_len);
+ if (ret != 0) {
+ goto exit;
+ }
+ ret = mbedtls_ecp_point_write_binary(&(ecp_key.grp), &ecp_key.Q,
+ MBEDTLS_ECP_PF_UNCOMPRESSED,
+ out_buf_len, out_buf, out_buf_size);
+
+exit:
+ mbedtls_ecp_keypair_free(&ecp_key);
+ return ret;
+}
+#endif /* MBEDTLS_PK_USE_PSA_EC_DATA */
/*
* EC public key is an EC point
@@ -617,15 +696,61 @@
* return code of mbedtls_ecp_point_read_binary() and leave p in a usable state.
*/
static int pk_get_ecpubkey(unsigned char **p, const unsigned char *end,
- mbedtls_ecp_keypair *key)
+ mbedtls_pk_context *pk)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
- if ((ret = mbedtls_ecp_point_read_binary(&key->grp, &key->Q,
- (const unsigned char *) *p, end - *p)) == 0) {
- ret = mbedtls_ecp_check_pubkey(&key->grp, &key->Q);
+#if defined(MBEDTLS_PK_USE_PSA_EC_DATA)
+ mbedtls_svc_key_id_t key;
+ psa_key_attributes_t key_attrs = PSA_KEY_ATTRIBUTES_INIT;
+ size_t len = (end - *p);
+
+ if (len > PSA_EXPORT_PUBLIC_KEY_MAX_SIZE) {
+ return MBEDTLS_ERR_PK_BAD_INPUT_DATA;
}
+ /* Compressed point format are not supported yet by PSA crypto. As a
+ * consequence ecp functions are used to "convert" the point to
+ * uncompressed format */
+ if ((**p == 0x02) || (**p == 0x03)) {
+ ret = pk_convert_compressed_ec(pk, *p, len,
+ &(pk->pub_raw_len), pk->pub_raw,
+ PSA_EXPORT_PUBLIC_KEY_MAX_SIZE);
+ if (ret != 0) {
+ return ret;
+ }
+ } else {
+ /* Uncompressed format */
+ if ((end - *p) > MBEDTLS_PK_MAX_EC_PUBKEY_RAW_LEN) {
+ return MBEDTLS_ERR_PK_BAD_INPUT_DATA;
+ }
+ memcpy(pk->pub_raw, *p, (end - *p));
+ pk->pub_raw_len = end - *p;
+ }
+
+ /* Validate the key by trying to importing it */
+ psa_set_key_usage_flags(&key_attrs, 0);
+ psa_set_key_algorithm(&key_attrs, PSA_ALG_ECDSA_ANY);
+ psa_set_key_type(&key_attrs, PSA_KEY_TYPE_ECC_PUBLIC_KEY(pk->ec_family));
+ psa_set_key_bits(&key_attrs, pk->ec_bits);
+
+ if ((psa_import_key(&key_attrs, pk->pub_raw, pk->pub_raw_len,
+ &key) != PSA_SUCCESS) ||
+ (psa_destroy_key(key) != PSA_SUCCESS)) {
+ mbedtls_platform_zeroize(pk->pub_raw, MBEDTLS_PK_MAX_EC_PUBKEY_RAW_LEN);
+ pk->pub_raw_len = 0;
+ return MBEDTLS_ERR_PK_BAD_INPUT_DATA;
+ }
+ ret = 0;
+#else /* MBEDTLS_PK_USE_PSA_EC_DATA */
+ mbedtls_ecp_keypair *ec_key = (mbedtls_ecp_keypair *) pk->pk_ctx;
+ if ((ret = mbedtls_ecp_point_read_binary(&ec_key->grp, &ec_key->Q,
+ (const unsigned char *) *p,
+ end - *p)) == 0) {
+ ret = mbedtls_ecp_check_pubkey(&ec_key->grp, &ec_key->Q);
+ }
+#endif /* MBEDTLS_PK_USE_PSA_EC_DATA */
+
/*
* We know mbedtls_ecp_point_read_binary consumed all bytes or failed
*/
@@ -796,14 +921,14 @@
if (pk_alg == MBEDTLS_PK_ECKEY_DH || pk_alg == MBEDTLS_PK_ECKEY) {
#if defined(MBEDTLS_PK_HAVE_RFC8410_CURVES)
if (mbedtls_pk_is_rfc8410_curve(ec_grp_id)) {
- ret = pk_use_ecparams_rfc8410(&alg_params, ec_grp_id, &mbedtls_pk_ec_rw(*pk)->grp);
+ ret = pk_use_ecparams_rfc8410(&alg_params, ec_grp_id, pk);
} else
#endif
{
- ret = pk_use_ecparams(&alg_params, &mbedtls_pk_ec_rw(*pk)->grp);
+ ret = pk_use_ecparams(&alg_params, pk);
}
if (ret == 0) {
- ret = pk_get_ecpubkey(p, end, mbedtls_pk_ec_rw(*pk));
+ ret = pk_get_ecpubkey(p, end, pk);
}
} else
#endif /* MBEDTLS_ECP_LIGHT */
@@ -1014,7 +1139,7 @@
/*
* Parse a SEC1 encoded private EC key
*/
-static int pk_parse_key_sec1_der(mbedtls_ecp_keypair *eck,
+static int pk_parse_key_sec1_der(mbedtls_pk_context *pk,
const unsigned char *key, size_t keylen,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng)
{
@@ -1026,6 +1151,7 @@
unsigned char *d;
unsigned char *end = p + keylen;
unsigned char *end2;
+ mbedtls_ecp_keypair *eck = mbedtls_pk_ec_rw(*pk);
/*
* RFC 5915, or SEC1 Appendix C.4
@@ -1074,7 +1200,7 @@
MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED |
0)) == 0) {
if ((ret = pk_get_ecparams(&p, p + len, ¶ms)) != 0 ||
- (ret = pk_use_ecparams(¶ms, &eck->grp)) != 0) {
+ (ret = pk_use_ecparams(¶ms, pk)) != 0) {
mbedtls_ecp_keypair_free(eck);
return ret;
}
@@ -1103,7 +1229,7 @@
MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
}
- if ((ret = pk_get_ecpubkey(&p, end2, eck)) == 0) {
+ if ((ret = pk_get_ecpubkey(&p, end2, pk)) == 0) {
pubkey_done = 1;
} else {
/*
@@ -1121,7 +1247,7 @@
}
if (!pubkey_done) {
- if ((ret = pk_derive_public_key(eck, d, d_len, f_rng, p_rng)) != 0) {
+ if ((ret = pk_derive_public_key(pk, d, d_len, f_rng, p_rng)) != 0) {
mbedtls_ecp_keypair_free(eck);
return ret;
}
@@ -1232,10 +1358,10 @@
if (pk_alg == MBEDTLS_PK_ECKEY || pk_alg == MBEDTLS_PK_ECKEY_DH) {
#if defined(MBEDTLS_PK_HAVE_RFC8410_CURVES)
if (mbedtls_pk_is_rfc8410_curve(ec_grp_id)) {
- if ((ret = pk_use_ecparams_rfc8410(¶ms, ec_grp_id,
- &mbedtls_pk_ec_rw(*pk)->grp)) != 0 ||
+ if ((ret =
+ pk_use_ecparams_rfc8410(¶ms, ec_grp_id, pk)) != 0 ||
(ret =
- pk_parse_key_rfc8410_der(mbedtls_pk_ec_rw(*pk), p, len, end, f_rng,
+ pk_parse_key_rfc8410_der(pk, p, len, end, f_rng,
p_rng)) != 0) {
mbedtls_pk_free(pk);
return ret;
@@ -1243,8 +1369,8 @@
} else
#endif
{
- if ((ret = pk_use_ecparams(¶ms, &mbedtls_pk_ec_rw(*pk)->grp)) != 0 ||
- (ret = pk_parse_key_sec1_der(mbedtls_pk_ec_rw(*pk), p, len, f_rng, p_rng)) != 0) {
+ if ((ret = pk_use_ecparams(¶ms, pk)) != 0 ||
+ (ret = pk_parse_key_sec1_der(pk, p, len, f_rng, p_rng)) != 0) {
mbedtls_pk_free(pk);
return ret;
}
@@ -1431,7 +1557,7 @@
pk_info = mbedtls_pk_info_from_type(MBEDTLS_PK_ECKEY);
if ((ret = mbedtls_pk_setup(pk, pk_info)) != 0 ||
- (ret = pk_parse_key_sec1_der(mbedtls_pk_ec_rw(*pk),
+ (ret = pk_parse_key_sec1_der(pk,
pem.buf, pem.buflen,
f_rng, p_rng)) != 0) {
mbedtls_pk_free(pk);
@@ -1555,18 +1681,18 @@
#if defined(MBEDTLS_ECP_LIGHT)
pk_info = mbedtls_pk_info_from_type(MBEDTLS_PK_ECKEY);
if (mbedtls_pk_setup(pk, pk_info) == 0 &&
- pk_parse_key_sec1_der(mbedtls_pk_ec_rw(*pk),
+ pk_parse_key_sec1_der(pk,
key, keylen, f_rng, p_rng) == 0) {
return 0;
}
mbedtls_pk_free(pk);
#endif /* MBEDTLS_ECP_LIGHT */
- /* If MBEDTLS_RSA_C is defined but MBEDTLS_ECP_C isn't,
+ /* If MBEDTLS_RSA_C is defined but MBEDTLS_ECP_LIGHT isn't,
* it is ok to leave the PK context initialized but not
* freed: It is the caller's responsibility to call pk_init()
* before calling this function, and to call pk_free()
- * when it fails. If MBEDTLS_ECP_C is defined but MBEDTLS_RSA_C
+ * when it fails. If MBEDTLS_ECP_LIGHT is defined but MBEDTLS_RSA_C
* isn't, this leads to mbedtls_pk_free() being called
* twice, once here and once by the caller, but this is
* also ok and in line with the mbedtls_pk_free() calls