Import mbedtls-3.6.0

Imports Mbed TLS 3.6.0 from https://github.com/Mbed-TLS/mbedtls.git
tags mbedtls-3.6.0, v3.6.0

Files that are not needed are removed:

cd lib/libmbedtls
rm -rf mbedtls
cp -R path/to/mbedtls-3.6.0/mbedtls .
cd mbedtls
rm CMakeLists.txt DartConfiguration.tcl Makefile
rm .gitignore .travis.yml .pylintrc .globalrc .mypy.ini BRANCHES.md
rm include/.gitignore include/CMakeLists.txt library/.gitignore
rm library/CMakeLists.txt library/Makefile
rm -r cmake
rm -rf .git .github doxygen configs programs scripts tests visualc
rm -rf 3rdparty ChangeLog.d docs pkgconfig .gitmodules .readthedocs.yaml
rm library/mps_*
cd ..
git add mbedtls

This time we leave library/psa_* present to enable TLS 1.3 features.

This is a complete overwrite of previous code so earlier changes in the
previous branch import/mbedtls-3.4.0 will be added on top of this commit.

Signed-off-by: Tom Van Eyck <tom.vaneyck@kuleuven.be>
Acked-by: Jens Wiklander <jens.wiklander@linaro.org>
diff --git a/lib/libmbedtls/mbedtls/library/pkwrite.h b/lib/libmbedtls/mbedtls/library/pkwrite.h
index 8aebd0c..01dc3d2 100644
--- a/lib/libmbedtls/mbedtls/library/pkwrite.h
+++ b/lib/libmbedtls/mbedtls/library/pkwrite.h
@@ -5,19 +5,7 @@
  */
 /*
  *  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
  */
 
 #ifndef MBEDTLS_PK_WRITE_H
@@ -27,6 +15,10 @@
 
 #include "mbedtls/pk.h"
 
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
+#include "psa/crypto.h"
+#endif /* MBEDTLS_USE_PSA_CRYPTO */
+
 /*
  * Max sizes of key per types. Shown as tag + len (+ content).
  */
@@ -73,7 +65,20 @@
 
 #endif /* MBEDTLS_RSA_C */
 
-#if defined(MBEDTLS_ECP_C)
+#if defined(MBEDTLS_PK_HAVE_ECC_KEYS)
+
+/* Find the maximum number of bytes necessary to store an EC point. When USE_PSA
+ * is defined this means looking for the maximum between PSA and built-in
+ * supported curves. */
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
+#define MBEDTLS_PK_MAX_ECC_BYTES   (PSA_BITS_TO_BYTES(PSA_VENDOR_ECC_MAX_CURVE_BITS) > \
+                                    MBEDTLS_ECP_MAX_BYTES ? \
+                                    PSA_BITS_TO_BYTES(PSA_VENDOR_ECC_MAX_CURVE_BITS) : \
+                                    MBEDTLS_ECP_MAX_BYTES)
+#else /* MBEDTLS_USE_PSA_CRYPTO */
+#define MBEDTLS_PK_MAX_ECC_BYTES   MBEDTLS_ECP_MAX_BYTES
+#endif /* MBEDTLS_USE_PSA_CRYPTO */
+
 /*
  * EC public keys:
  *  SubjectPublicKeyInfo  ::=  SEQUENCE  {      1 + 2
@@ -85,7 +90,7 @@
  *                                            + 2 * ECP_MAX (coords)    [1]
  *  }
  */
-#define MBEDTLS_PK_ECP_PUB_DER_MAX_BYTES    (30 + 2 * MBEDTLS_ECP_MAX_BYTES)
+#define MBEDTLS_PK_ECP_PUB_DER_MAX_BYTES    (30 + 2 * MBEDTLS_PK_MAX_ECC_BYTES)
 
 /*
  * EC private keys:
@@ -96,13 +101,21 @@
  *      publicKey  [1] BIT STRING OPTIONAL      1 + 2 + [1] above
  *    }
  */
-#define MBEDTLS_PK_ECP_PRV_DER_MAX_BYTES    (29 + 3 * MBEDTLS_ECP_MAX_BYTES)
+#define MBEDTLS_PK_ECP_PRV_DER_MAX_BYTES    (29 + 3 * MBEDTLS_PK_MAX_ECC_BYTES)
 
-#else /* MBEDTLS_ECP_C */
+#else /* MBEDTLS_PK_HAVE_ECC_KEYS */
 
 #define MBEDTLS_PK_ECP_PUB_DER_MAX_BYTES   0
 #define MBEDTLS_PK_ECP_PRV_DER_MAX_BYTES   0
 
-#endif /* MBEDTLS_ECP_C */
+#endif /* MBEDTLS_PK_HAVE_ECC_KEYS */
+
+/* Define the maximum available public key DER length based on the supported
+ * key types (EC and/or RSA). */
+#if (MBEDTLS_PK_RSA_PUB_DER_MAX_BYTES > MBEDTLS_PK_ECP_PUB_DER_MAX_BYTES)
+#define MBEDTLS_PK_WRITE_PUBKEY_MAX_SIZE    MBEDTLS_PK_RSA_PUB_DER_MAX_BYTES
+#else
+#define MBEDTLS_PK_WRITE_PUBKEY_MAX_SIZE    MBEDTLS_PK_ECP_PUB_DER_MAX_BYTES
+#endif
 
 #endif /* MBEDTLS_PK_WRITE_H */