Update lib/mbedtls from 2.28.3 to 4.2.0

.github/workflows/build.yml

@@ -258,7 +258,12 @@ jobs:
         pip install --break-system-packages wheel
         # requirements-dev.txt doesn't install on windows. (with msys2 python)
         # instead, pick a subset for what we want to do
-        pip install --break-system-packages cascadetoml jinja2 typer click intelhex
+        # jsonschema is needed by mbedtls' generate_driver_wrappers.py. Pin it below 4.18:
+        # 4.18 and later depend on rpds-py, a Rust extension with no wheel for msys2 python
+        # (SOABI cpython-3xx-x86_64-cygwin), and maturin refuses to build it from source
+        # ("Unsupported platform: x86_64-cygwin"). 4.17.3 uses attrs and pyrsistent instead,
+        # both of which install without a Rust toolchain.
+        pip install --break-system-packages cascadetoml jinja2 typer click intelhex 'jsonschema<4.18'
         # check that installed packages work....?
         which python; python --version; python -c "import cascadetoml"
         which python3; python3 --version; python3 -c "import cascadetoml"

.gitmodules

@@ -316,7 +316,7 @@
 	branch = circuitpython9
 [submodule "lib/mbedtls"]
 	path = lib/mbedtls
-	url = https://github.com/ARMmbed/mbedtls.git
+	url = https://github.com/Mbed-TLS/mbedtls.git
 [submodule "frozen/Adafruit_CircuitPython_UC8151D"]
 	path = frozen/Adafruit_CircuitPython_UC8151D
 	url = https://github.com/adafruit/Adafruit_CircuitPython_UC8151D

lib/mbedtls_config/crt_bundle.c

@@ -56,10 +56,6 @@ static crt_bundle_t s_crt_bundle;
 static int crt_check_signature(mbedtls_x509_crt *child, const uint8_t *pub_key_buf, size_t pub_key_len);
 
 
-#if MBEDTLS_VERSION_MAJOR < 3
-#define MBEDTLS_PRIVATE(x) x
-#endif
-
 static int crt_check_signature(mbedtls_x509_crt *child, const uint8_t *pub_key_buf, size_t pub_key_len) {
     int ret = 0;
     mbedtls_x509_crt parent;
@@ -74,33 +70,16 @@ static int crt_check_signature(mbedtls_x509_crt *child, const uint8_t *pub_key_b
     }
 
 
-    #if MBEDTLS_VERSION_MAJOR < 4
-    // Fast check to avoid expensive computations when not necessary
-    if (!mbedtls_pk_can_do(&parent.pk, child->MBEDTLS_PRIVATE(sig_pk))) {
-        LOGE(TAG, "Simple compare failed");
-        ret = -1;
-        goto cleanup;
-    }
-    #endif
-
     md_info = mbedtls_md_info_from_type(child->MBEDTLS_PRIVATE(sig_md));
     if ((ret = mbedtls_md(md_info, child->tbs.p, child->tbs.len, hash)) != 0) {
         LOGE(TAG, "Internal mbedTLS error %X", ret);
         goto cleanup;
     }
 
-    #if MBEDTLS_VERSION_MAJOR >= 4
     if ((ret = mbedtls_pk_verify_ext(
         child->MBEDTLS_PRIVATE(sig_pk), &parent.pk,
         child->MBEDTLS_PRIVATE(sig_md), hash, mbedtls_md_get_size(md_info),
         child->MBEDTLS_PRIVATE(sig).p, child->MBEDTLS_PRIVATE(sig).len)) != 0) {
-    #else
-    if ((ret = mbedtls_pk_verify_ext(
-        child->MBEDTLS_PRIVATE(sig_pk), child->MBEDTLS_PRIVATE(sig_opts), &parent.pk,
-        child->MBEDTLS_PRIVATE(sig_md), hash, mbedtls_md_get_size(md_info),
-        child->MBEDTLS_PRIVATE(sig).p, child->MBEDTLS_PRIVATE(sig).len)) != 0) {
-    #endif
-
         LOGE(TAG, "PK verify failed with error %X", ret);
         goto cleanup;
     }

lib/mbedtls_config/hashlib_psa_port.c

@@ -0,0 +1,32 @@
+// This file is part of the CircuitPython project: https://circuitpython.org
+//
+// SPDX-FileCopyrightText: Copyright (c) 2026 Dan Halbert for Adafruit Industries
+//
+// SPDX-License-Identifier: MIT
+
+// Platform glue for ports that build the PSA crypto core for hashlib but not for ssl.
+// The ssl equivalent is mbedtls_port.c; the two are mutually exclusive, because
+// CIRCUITPY_HASHLIB_MBEDTLS_ONLY means hashlib without ssl.
+
+#include <py/mpconfig.h>
+
+#if CIRCUITPY_HASHLIB_MBEDTLS_ONLY
+
+#include "psa/crypto.h"
+
+#include "shared-bindings/os/__init__.h"
+
+// Required by MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG. psa_crypto_init() initializes the RNG
+// subsystem even in a build that only ever hashes, so this has to exist.
+psa_status_t mbedtls_psa_external_get_random(
+    mbedtls_psa_external_random_context_t *context,
+    uint8_t *output, size_t output_size, size_t *output_length) {
+    (void)context;
+    if (!common_hal_os_urandom(output, output_size)) {
+        return PSA_ERROR_INSUFFICIENT_ENTROPY;
+    }
+    *output_length = output_size;
+    return PSA_SUCCESS;
+}
+
+#endif

lib/mbedtls_config/mbedtls_config.h

@@ -1,130 +1,102 @@
-/*
- * This file is part of the MicroPython project, http://micropython.org/
- *
- * The MIT License (MIT)
- *
- * Copyright (c) 2018-2019 Damien P. George
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-#ifndef MICROPY_INCLUDED_MBEDTLS_CONFIG_H
-#define MICROPY_INCLUDED_MBEDTLS_CONFIG_H
-
-// If you want to debug MBEDTLS uncomment the following and
-// Pass 3 to mbedtls_debug_set_threshold in socket_new
+// This file is part of the CircuitPython project: https://circuitpython.org
+//
+// SPDX-FileCopyrightText: Copyright (c) 2018-2019 Damien P. George
+// SPDX-FileCopyrightText: Copyright (c) 2026 Dan Halbert for Adafruit Industries
+//
+// SPDX-License-Identifier: MIT
+
+// mbedtls TLS and X.509 configuration, selected with MBEDTLS_CONFIG_FILE.
+//
+// As of mbedtls 4.0 this file covers only TLS and X.509. Everything cryptographic --
+// algorithms, key types, the platform hooks and the RNG -- is configured in
+// tf_psa_crypto_config.h next to this file, and selected with
+// TF_PSA_CRYPTO_CONFIG_FILE.
+
+#pragma once
+
+// If you want to debug mbedtls, uncomment the following. SSLSocket.c raises the debug
+// threshold to 4 when it is set.
 // #define MBEDTLS_DEBUG_C
 
-// Set mbedtls configuration
-#define MBEDTLS_PLATFORM_MEMORY
-#define MBEDTLS_PLATFORM_NO_STD_FUNCTIONS
-#define MBEDTLS_DEPRECATED_REMOVED
-#define MBEDTLS_ENTROPY_HARDWARE_ALT
-#define MBEDTLS_AES_ROM_TABLES
-#define MBEDTLS_CIPHER_MODE_CBC
-#define MBEDTLS_ECP_DP_SECP192R1_ENABLED
-#define MBEDTLS_ECP_DP_SECP224R1_ENABLED
-#define MBEDTLS_ECP_DP_SECP256R1_ENABLED
-#define MBEDTLS_ECP_DP_SECP384R1_ENABLED
-#define MBEDTLS_ECP_DP_SECP521R1_ENABLED
-#define MBEDTLS_ECP_DP_SECP192K1_ENABLED
-#define MBEDTLS_ECP_DP_SECP224K1_ENABLED
-#define MBEDTLS_ECP_DP_SECP256K1_ENABLED
-#define MBEDTLS_ECP_DP_BP256R1_ENABLED
-#define MBEDTLS_ECP_DP_BP384R1_ENABLED
-#define MBEDTLS_ECP_DP_BP512R1_ENABLED
-#define MBEDTLS_ECP_DP_CURVE25519_ENABLED
-#define MBEDTLS_ECP_NIST_OPTIM
-#define MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED
-#define MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED
-#define MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED
-#define MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED
-#define MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED
-#define MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED
-#define MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED
-#define MBEDTLS_KEY_EXCHANGE_PSK_ENABLED
-#define MBEDTLS_KEY_EXCHANGE_RSA_ENABLED
-#define MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED
-#define MBEDTLS_NO_PLATFORM_ENTROPY
-#define MBEDTLS_PKCS1_V15
-#define MBEDTLS_SHA256_SMALLER
-#define MBEDTLS_SSL_PROTO_TLS1
-#define MBEDTLS_SSL_PROTO_TLS1_1
+// Protocol versions
+
+// TLS 1.0 and 1.1 were removed in mbedtls 3.0, and were obsolete long before that.
+//
+// TLS 1.3 is available in 4.x but is turned off, to match espressif
+// It also cost 25648 bytes on Pico W, which has only ~50 KB of firmware
+// space left. Enabling it here would also require enabling
+// MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED, and PSA_WANT_ALG_HKDF* in
+// tf_psa_crypto_config.h for the 1.3 key schedule.
 #define MBEDTLS_SSL_PROTO_TLS1_2
+
+// DTLS is deliberately off: common_hal_ssl_sslcontext_wrap_socket() rejects anything
+// that is not SOCKETPOOL_SOCK_STREAM, so it could never be reached.
+
+#define MBEDTLS_SSL_CLI_C
+#define MBEDTLS_SSL_SRV_C
+#define MBEDTLS_SSL_TLS_C
+
+// Key exchanges. Without at least one of these there are no TLS 1.2 ciphersuites at
+// all, the ClientHello offers nothing, and the server answers with a fatal
+// handshake_failure alert. These two are what espressif enables
+// (CONFIG_MBEDTLS_KEY_EXCHANGE_ECDHE_{RSA,ECDSA}) and cover the public web. The PSK
+// and ECJPAKE exchanges that 4.x also still offers are not reachable from the ssl
+// module, and the static-RSA and DHE exchanges the mbedtls 2.28 config enabled are
+// gone from 4.x upstream.
+#define MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED
+#define MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED
+
+// Extensions
+
 #define MBEDTLS_SSL_SERVER_NAME_INDICATION
+#define MBEDTLS_SSL_KEEP_PEER_CERTIFICATE
+#define MBEDTLS_SSL_ENCRYPT_THEN_MAC
+#define MBEDTLS_SSL_EXTENDED_MASTER_SECRET
+
+// Buffers
 
-// Use a smaller output buffer to reduce size of SSL context
+// Accept a full-size record inbound, since we do not control what the peer sends,
+// but use a smaller outbound buffer to reduce the SSL context size.
 #define MBEDTLS_SSL_MAX_CONTENT_LEN (16384)
 #define MBEDTLS_SSL_IN_CONTENT_LEN  (MBEDTLS_SSL_MAX_CONTENT_LEN)
 #define MBEDTLS_SSL_OUT_CONTENT_LEN (4096)
 
-// Enable mbedtls modules
-#define MBEDTLS_AES_C
-#define MBEDTLS_ASN1_PARSE_C
-#define MBEDTLS_ASN1_WRITE_C
-#define MBEDTLS_BASE64_C
-#define MBEDTLS_BIGNUM_C
-#define MBEDTLS_CIPHER_C
-#define MBEDTLS_CTR_DRBG_C
-#define MBEDTLS_ECDH_C
-#define MBEDTLS_ECDSA_C
-#define MBEDTLS_ECP_C
-#define MBEDTLS_ENTROPY_C
-#define MBEDTLS_ERROR_C
-#define MBEDTLS_GCM_C
-#define MBEDTLS_MD_C
-#define MBEDTLS_MD5_C
-#define MBEDTLS_OID_C
-#define MBEDTLS_PKCS5_C
-#define MBEDTLS_PEM_PARSE_C
-#define MBEDTLS_PK_C
-#define MBEDTLS_PK_HAVE_ECC_KEYS
-#define MBEDTLS_PK_PARSE_C
-#define MBEDTLS_PLATFORM_C
-#define MBEDTLS_RSA_C
-#define MBEDTLS_SHA1_C
-#define MBEDTLS_SHA256_C
-#define MBEDTLS_SHA512_C
-#define MBEDTLS_SSL_CLI_C
-#define MBEDTLS_SSL_PROTO_DTLS
-#define MBEDTLS_SSL_SRV_C
-#define MBEDTLS_SSL_TLS_C
-#define MBEDTLS_TLS_DEFAULT_ALLOW_SHA1_IN_KEY_EXCHANGE
-#define MBEDTLS_X509_CRT_PARSE_C
+// X.509
+
 #define MBEDTLS_X509_USE_C
-#define MBEDTLS_HAVE_TIME
-#define MBEDTLS_DHM_C // needed by DHE_PSK
-#undef MBEDTLS_HAVE_TIME_DATE
-
-// Memory allocation hooks
-#include <stdlib.h>
-#include <stdio.h>
-void *m_tracked_calloc(size_t nmemb, size_t size);
-void m_tracked_free(void *ptr);
-#define MBEDTLS_PLATFORM_STD_CALLOC m_tracked_calloc
-#define MBEDTLS_PLATFORM_STD_FREE m_tracked_free
-#define MBEDTLS_PLATFORM_SNPRINTF_MACRO snprintf
-
-// Time hook
-#include <time.h>
-time_t rp2_rtctime_seconds(time_t *timer);
-#define MBEDTLS_PLATFORM_TIME_MACRO rp2_rtctime_seconds
-
-#include "mbedtls/check_config.h"
-
-#endif /* MICROPY_INCLUDED_MBEDTLS_CONFIG_H */
+#define MBEDTLS_X509_CRT_PARSE_C
+#define MBEDTLS_X509_RSASSA_PSS_SUPPORT
+
+// MBEDTLS_HAVE_TIME_DATE is deliberately left off, so certificate notBefore/notAfter
+// are not checked (see the BADCERT_EXPIRED/BADCERT_FUTURE tests in x509_crt.c, which
+// are compiled out without it). CircuitPython does not know the wall clock time unless
+// the program sets it explicitly, which often does not happen; with an unset clock,
+// checking the dates would reject valid certificates rather than catch expired ones.
+// espressif does not set CONFIG_MBEDTLS_HAVE_TIME_DATE either.
+//
+// Nothing else we enable consumes time -- no session tickets, no context
+// serialization, no DTLS, no TLS 1.3 -- so MBEDTLS_HAVE_TIME is off as well, and
+// mbedtls_port.c needs neither a wall clock nor mbedtls_ms_time().
+
+// Error strings
+
+// SSLSocket.c keys off MBEDTLS_ERROR_C to decide whether to put a message on the
+// OSError it raises. mbedtls's own error.c is not built; lib/mbedtls_errors supplies
+// a smaller mbedtls_strerror() instead.
+#define MBEDTLS_ERROR_C
+
+// Sanity checks
+//
+// mbedtls's own mbedtls_check_config.h only validates the prerequisites of options
+// that are enabled, so it says nothing when a whole category is missing. This is where
+// TF_PSA_CRYPTO_CONFIG_FILE replacing psa/crypto_config.h rather than overlaying it
+// bites: every default we rely on has to be restated here, and forgetting one produces
+// a build that compiles and links but cannot complete a handshake.
+#if !defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) &&   \
+    !defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) && \
+    !defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED) &&   \
+    !defined(MBEDTLS_KEY_EXCHANGE_PSK_ENABLED) &&         \
+    !defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
+#error "No MBEDTLS_KEY_EXCHANGE_* enabled: ciphersuite_definitions[] would be empty, " \
+    "so the ClientHello would offer nothing and every TLS 1.2 handshake would fail."
+#endif