Squashed commit upgrading to mbedtls-3.6.0

Squash merging branch import/mbedtls-3.6.0

0fc9291f4 ("libmbedtls: bignum: restore mbedtls_mpi_exp_mod() from v3.5.2")
0ef87b1e6 ("libmbedtls: reset minimum rsa key size")
70b079496 ("libmbedtls: adjust use of rsa pk_wrap API")
6cf76464f ("libmbedtls: allow inclusion of arm_neon.h")
27df5c911 ("libmbedtls: fix cipher_wrap.c for NIST AES Key Wrap mode")
aa584f9ed ("libmbedtls: fix cipher_wrap.c for chacha20 and chachapoly")
523ae957e ("libmbedtls: add fault mitigation in mbedtls_rsa_rsassa_pkcs1_v15_verify()")
30bdb1bbf ("libmbedtls: add fault mitigation in mbedtls_rsa_rsassa_pss_verify_ext()")
e45cdab62 ("libmbedtls: add SM2 curve")
d2fda4fc2 ("libmbedtls: fix no CRT issue")
ab0eb5515 ("libmbedtls: add interfaces in mbedtls for context memory operation")
7925a6f26 ("libmedtls: mpi_miller_rabin: increase count limit")
8eaf69279 ("libmbedtls: add mbedtls_mpi_init_mempool()")
12e83fc8d ("libmbedtls: make mbedtls_mpi_mont*() available")
f9e261da5 ("mbedtls: configure mbedtls to reach for config")
7b6f378d7 ("mbedtls: remove default include/mbedtls/config.h")
c16331743 ("Import mbedtls-3.6.0")

Signed-off-by: Tom Van Eyck <tom.vaneyck@kuleuven.be>
Acked-by: Jerome Forissier <jerome.forissier@linaro.org>
diff --git a/lib/libmbedtls/mbedtls/library/pkwrite.c b/lib/libmbedtls/mbedtls/library/pkwrite.c
index 2194c97..5e009c5 100644
--- a/lib/libmbedtls/mbedtls/library/pkwrite.c
+++ b/lib/libmbedtls/mbedtls/library/pkwrite.c
@@ -2,19 +2,7 @@
  *  Public Key layer for writing key files and structures
  *
  *  Copyright The Mbed TLS Contributors
- *  SPDX-License-Identifier: Apache-2.0
- *
- *  Licensed under the Apache License, Version 2.0 (the "License"); you may
- *  not use this file except in compliance with the License.
- *  You may obtain a copy of the License at
- *
- *  http://www.apache.org/licenses/LICENSE-2.0
- *
- *  Unless required by applicable law or agreed to in writing, software
- *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- *  See the License for the specific language governing permissions and
- *  limitations under the License.
+ *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
  */
 
 #include "common.h"
@@ -26,93 +14,92 @@
 #include "mbedtls/oid.h"
 #include "mbedtls/platform_util.h"
 #include "mbedtls/error.h"
+#include "pk_internal.h"
 
 #include <string.h>
 
-#if defined(MBEDTLS_RSA_C)
-#include "mbedtls/rsa.h"
-#endif
 #if defined(MBEDTLS_ECP_C)
 #include "mbedtls/bignum.h"
 #include "mbedtls/ecp.h"
 #include "mbedtls/platform_util.h"
 #endif
-#if defined(MBEDTLS_RSA_C) || defined(MBEDTLS_ECP_C)
-#include "pkwrite.h"
+#if defined(MBEDTLS_PK_HAVE_ECC_KEYS)
+#include "pk_internal.h"
 #endif
-#if defined(MBEDTLS_ECDSA_C)
-#include "mbedtls/ecdsa.h"
+#if defined(MBEDTLS_RSA_C) || defined(MBEDTLS_PK_HAVE_ECC_KEYS)
+#include "pkwrite.h"
 #endif
 #if defined(MBEDTLS_PEM_WRITE_C)
 #include "mbedtls/pem.h"
 #endif
+#if defined(MBEDTLS_RSA_C)
+#include "rsa_internal.h"
+#endif
 
 #if defined(MBEDTLS_USE_PSA_CRYPTO)
 #include "psa/crypto.h"
-#include "mbedtls/psa_util.h"
+#include "psa_util_internal.h"
 #endif
 #include "mbedtls/platform.h"
 
+/* Helpers for properly sizing buffers aimed at holding public keys or
+ * key-pairs based on build symbols. */
+#if defined(MBEDTLS_PK_USE_PSA_EC_DATA)
+#define PK_MAX_EC_PUBLIC_KEY_SIZE       PSA_EXPORT_PUBLIC_KEY_MAX_SIZE
+#define PK_MAX_EC_KEY_PAIR_SIZE         MBEDTLS_PSA_MAX_EC_KEY_PAIR_LENGTH
+#elif defined(MBEDTLS_USE_PSA_CRYPTO)
+#define PK_MAX_EC_PUBLIC_KEY_SIZE       PSA_EXPORT_PUBLIC_KEY_MAX_SIZE
+#define PK_MAX_EC_KEY_PAIR_SIZE         MBEDTLS_PSA_MAX_EC_KEY_PAIR_LENGTH
+#else
+#define PK_MAX_EC_PUBLIC_KEY_SIZE       MBEDTLS_ECP_MAX_PT_LEN
+#define PK_MAX_EC_KEY_PAIR_SIZE         MBEDTLS_ECP_MAX_BYTES
+#endif
+
+/******************************************************************************
+ * Internal functions for RSA keys.
+ ******************************************************************************/
 #if defined(MBEDTLS_RSA_C)
-/*
- *  RSAPublicKey ::= SEQUENCE {
- *      modulus           INTEGER,  -- n
- *      publicExponent    INTEGER   -- e
- *  }
- */
-static int pk_write_rsa_pubkey(unsigned char **p, unsigned char *start,
-                               mbedtls_rsa_context *rsa)
+static int pk_write_rsa_der(unsigned char **p, unsigned char *buf,
+                            const mbedtls_pk_context *pk)
 {
-    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
-    size_t len = 0;
-    mbedtls_mpi T;
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
+    if (mbedtls_pk_get_type(pk) == MBEDTLS_PK_OPAQUE) {
+        uint8_t tmp[PSA_EXPORT_KEY_PAIR_MAX_SIZE];
+        size_t len = 0, tmp_len = 0;
 
-    mbedtls_mpi_init(&T);
+        if (psa_export_key(pk->priv_id, tmp, sizeof(tmp), &tmp_len) != PSA_SUCCESS) {
+            return MBEDTLS_ERR_PK_BAD_INPUT_DATA;
+        }
+        *p -= tmp_len;
+        memcpy(*p, tmp, tmp_len);
+        len += tmp_len;
+        mbedtls_platform_zeroize(tmp, sizeof(tmp));
 
-    /* Export E */
-    if ((ret = mbedtls_rsa_export(rsa, NULL, NULL, NULL, NULL, &T)) != 0 ||
-        (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) {
-        goto end_of_export;
+        return (int) len;
     }
-    len += ret;
-
-    /* Export N */
-    if ((ret = mbedtls_rsa_export(rsa, &T, NULL, NULL, NULL, NULL)) != 0 ||
-        (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) {
-        goto end_of_export;
-    }
-    len += ret;
-
-end_of_export:
-
-    mbedtls_mpi_free(&T);
-    if (ret < 0) {
-        return ret;
-    }
-
-    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
-    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_CONSTRUCTED |
-                                                     MBEDTLS_ASN1_SEQUENCE));
-
-    return (int) len;
+#endif /* MBEDTLS_USE_PSA_CRYPTO */
+    return mbedtls_rsa_write_key(mbedtls_pk_rsa(*pk), buf, p);
 }
 #endif /* MBEDTLS_RSA_C */
 
-#if defined(MBEDTLS_ECP_C)
-/*
- * EC public key is an EC point
- */
+/******************************************************************************
+ * Internal functions for EC keys.
+ ******************************************************************************/
+#if defined(MBEDTLS_PK_HAVE_ECC_KEYS)
+#if defined(MBEDTLS_PK_USE_PSA_EC_DATA)
 static int pk_write_ec_pubkey(unsigned char **p, unsigned char *start,
-                              mbedtls_ecp_keypair *ec)
+                              const mbedtls_pk_context *pk)
 {
-    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t len = 0;
-    unsigned char buf[MBEDTLS_ECP_MAX_PT_LEN];
+    uint8_t buf[PK_MAX_EC_PUBLIC_KEY_SIZE];
 
-    if ((ret = mbedtls_ecp_point_write_binary(&ec->grp, &ec->Q,
-                                              MBEDTLS_ECP_PF_UNCOMPRESSED,
-                                              &len, buf, sizeof(buf))) != 0) {
-        return ret;
+    if (mbedtls_pk_get_type(pk) == MBEDTLS_PK_OPAQUE) {
+        if (psa_export_public_key(pk->priv_id, buf, sizeof(buf), &len) != PSA_SUCCESS) {
+            return MBEDTLS_ERR_PK_BAD_INPUT_DATA;
+        }
+    } else {
+        len = pk->pub_raw_len;
+        memcpy(buf, pk->pub_raw, len);
     }
 
     if (*p < start || (size_t) (*p - start) < len) {
@@ -124,6 +111,108 @@
 
     return (int) len;
 }
+#else /* MBEDTLS_PK_USE_PSA_EC_DATA */
+static int pk_write_ec_pubkey(unsigned char **p, unsigned char *start,
+                              const mbedtls_pk_context *pk)
+{
+    size_t len = 0;
+    unsigned char buf[PK_MAX_EC_PUBLIC_KEY_SIZE];
+    mbedtls_ecp_keypair *ec = mbedtls_pk_ec(*pk);
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
+    if (mbedtls_pk_get_type(pk) == MBEDTLS_PK_OPAQUE) {
+        if (psa_export_public_key(pk->priv_id, buf, sizeof(buf), &len) != PSA_SUCCESS) {
+            return MBEDTLS_ERR_PK_BAD_INPUT_DATA;
+        }
+        *p -= len;
+        memcpy(*p, buf, len);
+        return (int) len;
+    } else
+#endif /* MBEDTLS_USE_PSA_CRYPTO */
+    {
+        if ((ret = mbedtls_ecp_point_write_binary(&ec->grp, &ec->Q,
+                                                  MBEDTLS_ECP_PF_UNCOMPRESSED,
+                                                  &len, buf, sizeof(buf))) != 0) {
+            return ret;
+        }
+    }
+
+    if (*p < start || (size_t) (*p - start) < len) {
+        return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
+    }
+
+    *p -= len;
+    memcpy(*p, buf, len);
+
+    return (int) len;
+}
+#endif /* MBEDTLS_PK_USE_PSA_EC_DATA */
+
+/*
+ * privateKey  OCTET STRING -- always of length ceil(log2(n)/8)
+ */
+#if defined(MBEDTLS_PK_USE_PSA_EC_DATA)
+static int pk_write_ec_private(unsigned char **p, unsigned char *start,
+                               const mbedtls_pk_context *pk)
+{
+    size_t byte_length;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+    unsigned char tmp[PK_MAX_EC_KEY_PAIR_SIZE];
+    psa_status_t status;
+
+    if (mbedtls_pk_get_type(pk) == MBEDTLS_PK_OPAQUE) {
+        status = psa_export_key(pk->priv_id, tmp, sizeof(tmp), &byte_length);
+        if (status != PSA_SUCCESS) {
+            ret = PSA_PK_ECDSA_TO_MBEDTLS_ERR(status);
+            return ret;
+        }
+    } else {
+        status = psa_export_key(pk->priv_id, tmp, sizeof(tmp), &byte_length);
+        if (status != PSA_SUCCESS) {
+            ret = PSA_PK_ECDSA_TO_MBEDTLS_ERR(status);
+            goto exit;
+        }
+    }
+
+    ret = mbedtls_asn1_write_octet_string(p, start, tmp, byte_length);
+exit:
+    mbedtls_platform_zeroize(tmp, sizeof(tmp));
+    return ret;
+}
+#else /* MBEDTLS_PK_USE_PSA_EC_DATA */
+static int pk_write_ec_private(unsigned char **p, unsigned char *start,
+                               const mbedtls_pk_context *pk)
+{
+    size_t byte_length;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+    unsigned char tmp[PK_MAX_EC_KEY_PAIR_SIZE];
+
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
+    psa_status_t status;
+    if (mbedtls_pk_get_type(pk) == MBEDTLS_PK_OPAQUE) {
+        status = psa_export_key(pk->priv_id, tmp, sizeof(tmp), &byte_length);
+        if (status != PSA_SUCCESS) {
+            ret = PSA_PK_ECDSA_TO_MBEDTLS_ERR(status);
+            return ret;
+        }
+    } else
+#endif /* MBEDTLS_USE_PSA_CRYPTO */
+    {
+        mbedtls_ecp_keypair *ec = mbedtls_pk_ec_rw(*pk);
+        byte_length = (ec->grp.pbits + 7) / 8;
+
+        ret = mbedtls_ecp_write_key_ext(ec, &byte_length, tmp, sizeof(tmp));
+        if (ret != 0) {
+            goto exit;
+        }
+    }
+    ret = mbedtls_asn1_write_octet_string(p, start, tmp, byte_length);
+exit:
+    mbedtls_platform_zeroize(tmp, sizeof(tmp));
+    return ret;
+}
+#endif /* MBEDTLS_PK_USE_PSA_EC_DATA */
 
 /*
  * ECParameters ::= CHOICE {
@@ -131,14 +220,14 @@
  * }
  */
 static int pk_write_ec_param(unsigned char **p, unsigned char *start,
-                             mbedtls_ecp_keypair *ec)
+                             mbedtls_ecp_group_id grp_id)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t len = 0;
     const char *oid;
     size_t oid_len;
 
-    if ((ret = mbedtls_oid_get_oid_by_ec_grp(ec->grp.id, &oid, &oid_len)) != 0) {
+    if ((ret = mbedtls_oid_get_oid_by_ec_grp(grp_id, &oid, &oid_len)) != 0) {
         return ret;
     }
 
@@ -147,28 +236,178 @@
     return (int) len;
 }
 
+#if defined(MBEDTLS_PK_HAVE_RFC8410_CURVES)
 /*
- * privateKey  OCTET STRING -- always of length ceil(log2(n)/8)
+ * RFC8410 section 7
+ *
+ * OneAsymmetricKey ::= SEQUENCE {
+ *    version Version,
+ *    privateKeyAlgorithm PrivateKeyAlgorithmIdentifier,
+ *    privateKey PrivateKey,
+ *    attributes [0] IMPLICIT Attributes OPTIONAL,
+ *    ...,
+ *    [[2: publicKey [1] IMPLICIT PublicKey OPTIONAL ]],
+ *    ...
+ * }
+ * ...
+ * CurvePrivateKey ::= OCTET STRING
  */
-static int pk_write_ec_private(unsigned char **p, unsigned char *start,
-                               mbedtls_ecp_keypair *ec)
+static int pk_write_ec_rfc8410_der(unsigned char **p, unsigned char *buf,
+                                   const mbedtls_pk_context *pk)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
-    size_t byte_length = (ec->grp.pbits + 7) / 8;
-    unsigned char tmp[MBEDTLS_ECP_MAX_BYTES];
+    size_t len = 0;
+    size_t oid_len = 0;
+    const char *oid;
+    mbedtls_ecp_group_id grp_id;
 
-    ret = mbedtls_ecp_write_key(ec, tmp, byte_length);
-    if (ret != 0) {
-        goto exit;
+    /* privateKey */
+    MBEDTLS_ASN1_CHK_ADD(len, pk_write_ec_private(p, buf, pk));
+    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, buf, len));
+    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, buf, MBEDTLS_ASN1_OCTET_STRING));
+
+    grp_id = mbedtls_pk_get_ec_group_id(pk);
+    /* privateKeyAlgorithm */
+    if ((ret = mbedtls_oid_get_oid_by_ec_grp_algid(grp_id, &oid, &oid_len)) != 0) {
+        return ret;
     }
-    ret = mbedtls_asn1_write_octet_string(p, start, tmp, byte_length);
+    MBEDTLS_ASN1_CHK_ADD(len,
+                         mbedtls_asn1_write_algorithm_identifier_ext(p, buf, oid, oid_len, 0, 0));
 
-exit:
-    mbedtls_platform_zeroize(tmp, byte_length);
-    return ret;
+    /* version */
+    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_int(p, buf, 0));
+
+    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, buf, len));
+    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, buf, MBEDTLS_ASN1_CONSTRUCTED |
+                                                     MBEDTLS_ASN1_SEQUENCE));
+
+    return (int) len;
 }
-#endif /* MBEDTLS_ECP_C */
+#endif /* MBEDTLS_PK_HAVE_RFC8410_CURVES */
 
+/*
+ * RFC 5915, or SEC1 Appendix C.4
+ *
+ * ECPrivateKey ::= SEQUENCE {
+ *      version        INTEGER { ecPrivkeyVer1(1) } (ecPrivkeyVer1),
+ *      privateKey     OCTET STRING,
+ *      parameters [0] ECParameters {{ NamedCurve }} OPTIONAL,
+ *      publicKey  [1] BIT STRING OPTIONAL
+ *    }
+ */
+static int pk_write_ec_der(unsigned char **p, unsigned char *buf,
+                           const mbedtls_pk_context *pk)
+{
+    size_t len = 0;
+    int ret;
+    size_t pub_len = 0, par_len = 0;
+    mbedtls_ecp_group_id grp_id;
+
+    /* publicKey */
+    MBEDTLS_ASN1_CHK_ADD(pub_len, pk_write_ec_pubkey(p, buf, pk));
+
+    if (*p - buf < 1) {
+        return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
+    }
+    (*p)--;
+    **p = 0;
+    pub_len += 1;
+
+    MBEDTLS_ASN1_CHK_ADD(pub_len, mbedtls_asn1_write_len(p, buf, pub_len));
+    MBEDTLS_ASN1_CHK_ADD(pub_len, mbedtls_asn1_write_tag(p, buf, MBEDTLS_ASN1_BIT_STRING));
+
+    MBEDTLS_ASN1_CHK_ADD(pub_len, mbedtls_asn1_write_len(p, buf, pub_len));
+    MBEDTLS_ASN1_CHK_ADD(pub_len, mbedtls_asn1_write_tag(p, buf,
+                                                         MBEDTLS_ASN1_CONTEXT_SPECIFIC |
+                                                         MBEDTLS_ASN1_CONSTRUCTED | 1));
+    len += pub_len;
+
+    /* parameters */
+    grp_id = mbedtls_pk_get_ec_group_id(pk);
+    MBEDTLS_ASN1_CHK_ADD(par_len, pk_write_ec_param(p, buf, grp_id));
+    MBEDTLS_ASN1_CHK_ADD(par_len, mbedtls_asn1_write_len(p, buf, par_len));
+    MBEDTLS_ASN1_CHK_ADD(par_len, mbedtls_asn1_write_tag(p, buf,
+                                                         MBEDTLS_ASN1_CONTEXT_SPECIFIC |
+                                                         MBEDTLS_ASN1_CONSTRUCTED | 0));
+    len += par_len;
+
+    /* privateKey */
+    MBEDTLS_ASN1_CHK_ADD(len, pk_write_ec_private(p, buf, pk));
+
+    /* version */
+    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_int(p, buf, 1));
+
+    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, buf, len));
+    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, buf, MBEDTLS_ASN1_CONSTRUCTED |
+                                                     MBEDTLS_ASN1_SEQUENCE));
+
+    return (int) len;
+}
+#endif /* MBEDTLS_PK_HAVE_ECC_KEYS */
+
+/******************************************************************************
+ * Internal functions for Opaque keys.
+ ******************************************************************************/
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
+static int pk_write_opaque_pubkey(unsigned char **p, unsigned char *start,
+                                  const mbedtls_pk_context *pk)
+{
+    size_t buffer_size;
+    size_t len = 0;
+
+    if (*p < start) {
+        return MBEDTLS_ERR_PK_BAD_INPUT_DATA;
+    }
+
+    buffer_size = (size_t) (*p - start);
+    if (psa_export_public_key(pk->priv_id, start, buffer_size,
+                              &len) != PSA_SUCCESS) {
+        return MBEDTLS_ERR_PK_BAD_INPUT_DATA;
+    }
+
+    *p -= len;
+    memmove(*p, start, len);
+
+    return (int) len;
+}
+#endif /* MBEDTLS_USE_PSA_CRYPTO */
+
+/******************************************************************************
+ * Generic helpers
+ ******************************************************************************/
+
+/* Extend the public mbedtls_pk_get_type() by getting key type also in case of
+ * opaque keys. */
+static mbedtls_pk_type_t pk_get_type_ext(const mbedtls_pk_context *pk)
+{
+    mbedtls_pk_type_t pk_type = mbedtls_pk_get_type(pk);
+
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
+    if (pk_type == MBEDTLS_PK_OPAQUE) {
+        psa_key_attributes_t opaque_attrs = PSA_KEY_ATTRIBUTES_INIT;
+        psa_key_type_t opaque_key_type;
+
+        if (psa_get_key_attributes(pk->priv_id, &opaque_attrs) != PSA_SUCCESS) {
+            return MBEDTLS_PK_NONE;
+        }
+        opaque_key_type = psa_get_key_type(&opaque_attrs);
+        psa_reset_key_attributes(&opaque_attrs);
+
+        if (PSA_KEY_TYPE_IS_ECC(opaque_key_type)) {
+            return MBEDTLS_PK_ECKEY;
+        } else if (PSA_KEY_TYPE_IS_RSA(opaque_key_type)) {
+            return MBEDTLS_PK_RSA;
+        } else {
+            return MBEDTLS_PK_NONE;
+        }
+    } else
+#endif
+    return pk_type;
+}
+
+/******************************************************************************
+ * Public functions for writing private/public DER keys.
+ ******************************************************************************/
 int mbedtls_pk_write_pubkey(unsigned char **p, unsigned char *start,
                             const mbedtls_pk_context *key)
 {
@@ -177,31 +416,17 @@
 
 #if defined(MBEDTLS_RSA_C)
     if (mbedtls_pk_get_type(key) == MBEDTLS_PK_RSA) {
-        MBEDTLS_ASN1_CHK_ADD(len, pk_write_rsa_pubkey(p, start, mbedtls_pk_rsa(*key)));
+        MBEDTLS_ASN1_CHK_ADD(len, mbedtls_rsa_write_pubkey(mbedtls_pk_rsa(*key), start, p));
     } else
 #endif
-#if defined(MBEDTLS_ECP_C)
+#if defined(MBEDTLS_PK_HAVE_ECC_KEYS)
     if (mbedtls_pk_get_type(key) == MBEDTLS_PK_ECKEY) {
-        MBEDTLS_ASN1_CHK_ADD(len, pk_write_ec_pubkey(p, start, mbedtls_pk_ec(*key)));
+        MBEDTLS_ASN1_CHK_ADD(len, pk_write_ec_pubkey(p, start, key));
     } else
 #endif
 #if defined(MBEDTLS_USE_PSA_CRYPTO)
     if (mbedtls_pk_get_type(key) == MBEDTLS_PK_OPAQUE) {
-        size_t buffer_size;
-        mbedtls_svc_key_id_t *key_id = (mbedtls_svc_key_id_t *) key->pk_ctx;
-
-        if (*p < start) {
-            return MBEDTLS_ERR_PK_BAD_INPUT_DATA;
-        }
-
-        buffer_size = (size_t) (*p - start);
-        if (psa_export_public_key(*key_id, start, buffer_size, &len)
-            != PSA_SUCCESS) {
-            return MBEDTLS_ERR_PK_BAD_INPUT_DATA;
-        } else {
-            *p -= len;
-            memmove(*p, start, len);
-        }
+        MBEDTLS_ASN1_CHK_ADD(len, pk_write_opaque_pubkey(p, start, key));
     } else
 #endif /* MBEDTLS_USE_PSA_CRYPTO */
     return MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE;
@@ -213,9 +438,10 @@
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     unsigned char *c;
-    size_t len = 0, par_len = 0, oid_len;
+    int has_par = 1;
+    size_t len = 0, par_len = 0, oid_len = 0;
     mbedtls_pk_type_t pk_type;
-    const char *oid;
+    const char *oid = NULL;
 
     if (size == 0) {
         return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
@@ -240,64 +466,33 @@
     MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, buf, len));
     MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&c, buf, MBEDTLS_ASN1_BIT_STRING));
 
-    pk_type = mbedtls_pk_get_type(key);
-#if defined(MBEDTLS_ECP_C)
-    if (pk_type == MBEDTLS_PK_ECKEY) {
-        MBEDTLS_ASN1_CHK_ADD(par_len, pk_write_ec_param(&c, buf, mbedtls_pk_ec(*key)));
-    }
-#endif
-#if defined(MBEDTLS_USE_PSA_CRYPTO)
-    if (pk_type == MBEDTLS_PK_OPAQUE) {
-        psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT;
-        psa_key_type_t key_type;
-        mbedtls_svc_key_id_t key_id;
-        psa_ecc_family_t curve;
-        size_t bits;
+    pk_type = pk_get_type_ext(key);
 
-        key_id = *((mbedtls_svc_key_id_t *) key->pk_ctx);
-        if (PSA_SUCCESS != psa_get_key_attributes(key_id, &attributes)) {
-            return MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED;
-        }
-        key_type = psa_get_key_type(&attributes);
-        bits = psa_get_key_bits(&attributes);
-        psa_reset_key_attributes(&attributes);
-
-        if (PSA_KEY_TYPE_IS_ECC_KEY_PAIR(key_type)) {
-            curve = PSA_KEY_TYPE_ECC_GET_FAMILY(key_type);
-            if (curve == 0) {
-                return MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE;
-            }
-
-            ret = mbedtls_psa_get_ecc_oid_from_id(curve, bits,
-                                                  &oid, &oid_len);
+#if defined(MBEDTLS_PK_HAVE_ECC_KEYS)
+    if (pk_get_type_ext(key) == MBEDTLS_PK_ECKEY) {
+        mbedtls_ecp_group_id ec_grp_id = mbedtls_pk_get_ec_group_id(key);
+        if (MBEDTLS_PK_IS_RFC8410_GROUP_ID(ec_grp_id)) {
+            ret = mbedtls_oid_get_oid_by_ec_grp_algid(ec_grp_id, &oid, &oid_len);
             if (ret != 0) {
-                return MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE;
+                return ret;
             }
-
-            /* Write EC algorithm parameters; that's akin
-             * to pk_write_ec_param() above. */
-            MBEDTLS_ASN1_CHK_ADD(par_len, mbedtls_asn1_write_oid(&c, buf,
-                                                                 oid,
-                                                                 oid_len));
-
-            /* The rest of the function works as for legacy EC contexts. */
-            pk_type = MBEDTLS_PK_ECKEY;
-        } else if (PSA_KEY_TYPE_IS_RSA(key_type)) {
-            /* The rest of the function works as for legacy RSA contexts. */
-            pk_type = MBEDTLS_PK_RSA;
+            has_par = 0;
         } else {
-            return MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE;
+            MBEDTLS_ASN1_CHK_ADD(par_len, pk_write_ec_param(&c, buf, ec_grp_id));
         }
     }
-#endif /* MBEDTLS_USE_PSA_CRYPTO */
+#endif /* MBEDTLS_PK_HAVE_ECC_KEYS */
 
-    if ((ret = mbedtls_oid_get_oid_by_pk_alg(pk_type, &oid,
-                                             &oid_len)) != 0) {
-        return ret;
+    /* At this point oid_len is not null only for EC Montgomery keys. */
+    if (oid_len == 0) {
+        ret = mbedtls_oid_get_oid_by_pk_alg(pk_type, &oid, &oid_len);
+        if (ret != 0) {
+            return ret;
+        }
     }
 
-    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_algorithm_identifier(&c, buf, oid, oid_len,
-                                                                      par_len));
+    MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_algorithm_identifier_ext(&c, buf, oid, oid_len,
+                                                                          par_len, has_par));
 
     MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, buf, len));
     MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&c, buf, MBEDTLS_ASN1_CONSTRUCTED |
@@ -308,9 +503,7 @@
 
 int mbedtls_pk_write_key_der(const mbedtls_pk_context *key, unsigned char *buf, size_t size)
 {
-    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     unsigned char *c;
-    size_t len = 0;
 
     if (size == 0) {
         return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
@@ -319,160 +512,28 @@
     c = buf + size;
 
 #if defined(MBEDTLS_RSA_C)
-    if (mbedtls_pk_get_type(key) == MBEDTLS_PK_RSA) {
-        mbedtls_mpi T; /* Temporary holding the exported parameters */
-        mbedtls_rsa_context *rsa = mbedtls_pk_rsa(*key);
-
-        /*
-         * Export the parameters one after another to avoid simultaneous copies.
-         */
-
-        mbedtls_mpi_init(&T);
-
-        /* Export QP */
-        if ((ret = mbedtls_rsa_export_crt(rsa, NULL, NULL, &T)) != 0 ||
-            (ret = mbedtls_asn1_write_mpi(&c, buf, &T)) < 0) {
-            goto end_of_export;
-        }
-        len += ret;
-
-        /* Export DQ */
-        if ((ret = mbedtls_rsa_export_crt(rsa, NULL, &T, NULL)) != 0 ||
-            (ret = mbedtls_asn1_write_mpi(&c, buf, &T)) < 0) {
-            goto end_of_export;
-        }
-        len += ret;
-
-        /* Export DP */
-        if ((ret = mbedtls_rsa_export_crt(rsa, &T, NULL, NULL)) != 0 ||
-            (ret = mbedtls_asn1_write_mpi(&c, buf, &T)) < 0) {
-            goto end_of_export;
-        }
-        len += ret;
-
-        /* Export Q */
-        if ((ret = mbedtls_rsa_export(rsa, NULL, NULL,
-                                      &T, NULL, NULL)) != 0 ||
-            (ret = mbedtls_asn1_write_mpi(&c, buf, &T)) < 0) {
-            goto end_of_export;
-        }
-        len += ret;
-
-        /* Export P */
-        if ((ret = mbedtls_rsa_export(rsa, NULL, &T,
-                                      NULL, NULL, NULL)) != 0 ||
-            (ret = mbedtls_asn1_write_mpi(&c, buf, &T)) < 0) {
-            goto end_of_export;
-        }
-        len += ret;
-
-        /* Export D */
-        if ((ret = mbedtls_rsa_export(rsa, NULL, NULL,
-                                      NULL, &T, NULL)) != 0 ||
-            (ret = mbedtls_asn1_write_mpi(&c, buf, &T)) < 0) {
-            goto end_of_export;
-        }
-        len += ret;
-
-        /* Export E */
-        if ((ret = mbedtls_rsa_export(rsa, NULL, NULL,
-                                      NULL, NULL, &T)) != 0 ||
-            (ret = mbedtls_asn1_write_mpi(&c, buf, &T)) < 0) {
-            goto end_of_export;
-        }
-        len += ret;
-
-        /* Export N */
-        if ((ret = mbedtls_rsa_export(rsa, &T, NULL,
-                                      NULL, NULL, NULL)) != 0 ||
-            (ret = mbedtls_asn1_write_mpi(&c, buf, &T)) < 0) {
-            goto end_of_export;
-        }
-        len += ret;
-
-end_of_export:
-
-        mbedtls_mpi_free(&T);
-        if (ret < 0) {
-            return ret;
-        }
-
-        MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_int(&c, buf, 0));
-        MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, buf, len));
-        MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&c,
-                                                         buf, MBEDTLS_ASN1_CONSTRUCTED |
-                                                         MBEDTLS_ASN1_SEQUENCE));
+    if (pk_get_type_ext(key) == MBEDTLS_PK_RSA) {
+        return pk_write_rsa_der(&c, buf, key);
     } else
 #endif /* MBEDTLS_RSA_C */
-#if defined(MBEDTLS_ECP_C)
-    if (mbedtls_pk_get_type(key) == MBEDTLS_PK_ECKEY) {
-        mbedtls_ecp_keypair *ec = mbedtls_pk_ec(*key);
-        size_t pub_len = 0, par_len = 0;
-
-        /*
-         * RFC 5915, or SEC1 Appendix C.4
-         *
-         * ECPrivateKey ::= SEQUENCE {
-         *      version        INTEGER { ecPrivkeyVer1(1) } (ecPrivkeyVer1),
-         *      privateKey     OCTET STRING,
-         *      parameters [0] ECParameters {{ NamedCurve }} OPTIONAL,
-         *      publicKey  [1] BIT STRING OPTIONAL
-         *    }
-         */
-
-        /* publicKey */
-        MBEDTLS_ASN1_CHK_ADD(pub_len, pk_write_ec_pubkey(&c, buf, ec));
-
-        if (c - buf < 1) {
-            return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
+#if defined(MBEDTLS_PK_HAVE_ECC_KEYS)
+    if (pk_get_type_ext(key) == MBEDTLS_PK_ECKEY) {
+#if defined(MBEDTLS_PK_HAVE_RFC8410_CURVES)
+        if (mbedtls_pk_is_rfc8410(key)) {
+            return pk_write_ec_rfc8410_der(&c, buf, key);
         }
-        *--c = 0;
-        pub_len += 1;
-
-        MBEDTLS_ASN1_CHK_ADD(pub_len, mbedtls_asn1_write_len(&c, buf, pub_len));
-        MBEDTLS_ASN1_CHK_ADD(pub_len, mbedtls_asn1_write_tag(&c, buf, MBEDTLS_ASN1_BIT_STRING));
-
-        MBEDTLS_ASN1_CHK_ADD(pub_len, mbedtls_asn1_write_len(&c, buf, pub_len));
-        MBEDTLS_ASN1_CHK_ADD(pub_len, mbedtls_asn1_write_tag(&c, buf,
-                                                             MBEDTLS_ASN1_CONTEXT_SPECIFIC |
-                                                             MBEDTLS_ASN1_CONSTRUCTED | 1));
-        len += pub_len;
-
-        /* parameters */
-        MBEDTLS_ASN1_CHK_ADD(par_len, pk_write_ec_param(&c, buf, ec));
-
-        MBEDTLS_ASN1_CHK_ADD(par_len, mbedtls_asn1_write_len(&c, buf, par_len));
-        MBEDTLS_ASN1_CHK_ADD(par_len, mbedtls_asn1_write_tag(&c, buf,
-                                                             MBEDTLS_ASN1_CONTEXT_SPECIFIC |
-                                                             MBEDTLS_ASN1_CONSTRUCTED | 0));
-        len += par_len;
-
-        /* privateKey */
-        MBEDTLS_ASN1_CHK_ADD(len, pk_write_ec_private(&c, buf, ec));
-
-        /* version */
-        MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_int(&c, buf, 1));
-
-        MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, buf, len));
-        MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&c, buf, MBEDTLS_ASN1_CONSTRUCTED |
-                                                         MBEDTLS_ASN1_SEQUENCE));
+#endif /* MBEDTLS_PK_HAVE_RFC8410_CURVES */
+        return pk_write_ec_der(&c, buf, key);
     } else
-#endif /* MBEDTLS_ECP_C */
+#endif /* MBEDTLS_PK_HAVE_ECC_KEYS */
     return MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE;
-
-    return (int) len;
 }
 
+/******************************************************************************
+ * Public functions for wrinting private/public PEM keys.
+ ******************************************************************************/
 #if defined(MBEDTLS_PEM_WRITE_C)
 
-#define PEM_BEGIN_PUBLIC_KEY    "-----BEGIN PUBLIC KEY-----\n"
-#define PEM_END_PUBLIC_KEY      "-----END PUBLIC KEY-----\n"
-
-#define PEM_BEGIN_PRIVATE_KEY_RSA   "-----BEGIN RSA PRIVATE KEY-----\n"
-#define PEM_END_PRIVATE_KEY_RSA     "-----END RSA PRIVATE KEY-----\n"
-#define PEM_BEGIN_PRIVATE_KEY_EC    "-----BEGIN EC PRIVATE KEY-----\n"
-#define PEM_END_PRIVATE_KEY_EC      "-----END EC PRIVATE KEY-----\n"
-
 #define PUB_DER_MAX_BYTES                                                   \
     (MBEDTLS_PK_RSA_PUB_DER_MAX_BYTES > MBEDTLS_PK_ECP_PUB_DER_MAX_BYTES ? \
      MBEDTLS_PK_RSA_PUB_DER_MAX_BYTES : MBEDTLS_PK_ECP_PUB_DER_MAX_BYTES)
@@ -483,55 +544,77 @@
 int mbedtls_pk_write_pubkey_pem(const mbedtls_pk_context *key, unsigned char *buf, size_t size)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
-    unsigned char output_buf[PUB_DER_MAX_BYTES];
+    unsigned char *output_buf = NULL;
+    output_buf = mbedtls_calloc(1, PUB_DER_MAX_BYTES);
+    if (output_buf == NULL) {
+        return MBEDTLS_ERR_PK_ALLOC_FAILED;
+    }
     size_t olen = 0;
 
     if ((ret = mbedtls_pk_write_pubkey_der(key, output_buf,
-                                           sizeof(output_buf))) < 0) {
-        return ret;
+                                           PUB_DER_MAX_BYTES)) < 0) {
+        goto cleanup;
     }
 
-    if ((ret = mbedtls_pem_write_buffer(PEM_BEGIN_PUBLIC_KEY, PEM_END_PUBLIC_KEY,
-                                        output_buf + sizeof(output_buf) - ret,
+    if ((ret = mbedtls_pem_write_buffer(PEM_BEGIN_PUBLIC_KEY "\n", PEM_END_PUBLIC_KEY "\n",
+                                        output_buf + PUB_DER_MAX_BYTES - ret,
                                         ret, buf, size, &olen)) != 0) {
-        return ret;
+        goto cleanup;
     }
 
-    return 0;
+    ret = 0;
+cleanup:
+    mbedtls_free(output_buf);
+    return ret;
 }
 
 int mbedtls_pk_write_key_pem(const mbedtls_pk_context *key, unsigned char *buf, size_t size)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
-    unsigned char output_buf[PRV_DER_MAX_BYTES];
+    unsigned char *output_buf = NULL;
+    output_buf = mbedtls_calloc(1, PRV_DER_MAX_BYTES);
+    if (output_buf == NULL) {
+        return MBEDTLS_ERR_PK_ALLOC_FAILED;
+    }
     const char *begin, *end;
     size_t olen = 0;
 
-    if ((ret = mbedtls_pk_write_key_der(key, output_buf, sizeof(output_buf))) < 0) {
-        return ret;
+    if ((ret = mbedtls_pk_write_key_der(key, output_buf, PRV_DER_MAX_BYTES)) < 0) {
+        goto cleanup;
     }
 
 #if defined(MBEDTLS_RSA_C)
-    if (mbedtls_pk_get_type(key) == MBEDTLS_PK_RSA) {
-        begin = PEM_BEGIN_PRIVATE_KEY_RSA;
-        end = PEM_END_PRIVATE_KEY_RSA;
+    if (pk_get_type_ext(key) == MBEDTLS_PK_RSA) {
+        begin = PEM_BEGIN_PRIVATE_KEY_RSA "\n";
+        end = PEM_END_PRIVATE_KEY_RSA "\n";
     } else
 #endif
-#if defined(MBEDTLS_ECP_C)
-    if (mbedtls_pk_get_type(key) == MBEDTLS_PK_ECKEY) {
-        begin = PEM_BEGIN_PRIVATE_KEY_EC;
-        end = PEM_END_PRIVATE_KEY_EC;
+#if defined(MBEDTLS_PK_HAVE_ECC_KEYS)
+    if (pk_get_type_ext(key) == MBEDTLS_PK_ECKEY) {
+        if (mbedtls_pk_is_rfc8410(key)) {
+            begin = PEM_BEGIN_PRIVATE_KEY_PKCS8 "\n";
+            end = PEM_END_PRIVATE_KEY_PKCS8 "\n";
+        } else {
+            begin = PEM_BEGIN_PRIVATE_KEY_EC "\n";
+            end = PEM_END_PRIVATE_KEY_EC "\n";
+        }
     } else
-#endif
-    return MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE;
-
-    if ((ret = mbedtls_pem_write_buffer(begin, end,
-                                        output_buf + sizeof(output_buf) - ret,
-                                        ret, buf, size, &olen)) != 0) {
-        return ret;
+#endif /* MBEDTLS_PK_HAVE_ECC_KEYS */
+    {
+        ret = MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE;
+        goto cleanup;
     }
 
-    return 0;
+    if ((ret = mbedtls_pem_write_buffer(begin, end,
+                                        output_buf + PRV_DER_MAX_BYTES - ret,
+                                        ret, buf, size, &olen)) != 0) {
+        goto cleanup;
+    }
+
+    ret = 0;
+cleanup:
+    mbedtls_zeroize_and_free(output_buf, PRV_DER_MAX_BYTES);
+    return ret;
 }
 #endif /* MBEDTLS_PEM_WRITE_C */