lib/mbedtls_errors: Add code to patch mbedtls for shortened error strs.

The file `mbedtls_errors/mp_mbedtls_errors.c` can be used instead of
`mbedtls/library/error.c` to give shorter error strings, reducing the build
size of the error strings from about 12-16kB down to about 2-5kB.

lib/mbedtls_errors/README.md

@@ -0,0 +1,42 @@
+MBEDTLS Error Strings for MicroPython
+=====================================
+
+This directory contains source code and tools to rework the Mbedtls error strings for
+micropython to use less space. In short, instead of storing and printing something like
+"SSL - Our own certificate(s) is/are too large to send in an SSL message" it prints
+the name of the error #define, which would be "MBEDTLS_ERR_SSL_CERTIFICATE_TOO_LARGE" in
+this case, and only stores `SSL_CERTIFICATE_TOO_LARGE` in flash. The exact Mbedtls error
+defines are used because they're easy to search for to find more detailed information.
+
+Mbedtls defines a specific format for error value #defines and
+includes a Perl script to gather all `MBEDTLS_ERR` defines from includes files together with
+english error text. From that the Perl script generates `mbedtls_strerror()`. The files in this
+directory modify this process to produce a more space efficient error lookup table with
+shorter error strings.
+
+The files are as follows:
+- `generate_errors.diff` - diff for original mbedtls perl script
+- `error.fmt` - modified code template for MicroPython
+- `mp_mbedtls_errors.c` - source file with `mbedtls_strerror` this is built using the include
+  files in `../mbedtls`
+- `do-mp.sh` - shell script to produce `mp_mbedtls_errors.c`
+- `tester.c` - simple C main to test `mp_mbedtls_errors.c` locally on a dev box
+- `do-test.sh` - shell script to produce `mp_mbedtls_errors.c` and compile the `tester` app
+- `do-esp32.sh` - shell script to produce `esp32_mbedtls_errors.c` -- see below
+
+In order not to store multiple copies of `mbedtls_errors.c`
+([https://github.com/micropython/micropython/pull/5819#discussion_r445528006](see))
+it is assumed that all ports use the same version of mbedtls with the same error #defines.
+This is true as of MP v1.13, and ESP-IDF versions 3.3.2 and 4.0.1. If anything changes in the
+future the `do-esp32.sh` script can be used to generate an esp32-specific version.
+
+### How-to
+
+- To build MicroPython all that is needed is to include the `mp_mbedtls_errors.c` into the build
+  (the Makefiles do this automatically). Note that Perl is not needed for routine MicroPython
+  builds.
+- When a new version of Mbedtls is pulled-in the `do-mp.sh` script should be run to
+  re-generate `mp_mbedtls_errors.c`.
+- The `tester` app should be run if changes to the string handling in `error.fmt` are made:
+  it tests that there is not an off-by-one error in the string copying/appending, etc.
+- To include `mbedtls_strerror` error strings define `MBEDTLS_ERROR_C` in the build.

lib/mbedtls_errors/do-esp32.sh

@@ -0,0 +1,7 @@
+#! /bin/bash -e
+# Generate esp32_mbedtls_errors.c for use in the Esp32 port, with the ESP-IDF version of mbedtls
+# The IDF_PATH env var must be set to the top-level dir of ESPIDF
+echo "IDF_PATH=$IDF_PATH"
+MBEDTLS=$IDF_PATH/components/mbedtls/mbedtls
+patch -o esp32_generate_errors.pl $MBEDTLS/scripts/generate_errors.pl <generate_errors.diff
+perl ./esp32_generate_errors.pl $MBEDTLS/include/mbedtls . esp32_mbedtls_errors.c

lib/mbedtls_errors/do-mp.sh

@@ -0,0 +1,4 @@
+#! /bin/bash -e
+# Generate mp_mbedtls_errors.c for inclusion in ports that use $MPY/lib/mbedtls
+patch -o mp_generate_errors.pl ../mbedtls/scripts/generate_errors.pl <generate_errors.diff
+perl ./mp_generate_errors.pl ../mbedtls/include/mbedtls . mp_mbedtls_errors.c

lib/mbedtls_errors/do-test.sh

@@ -0,0 +1,4 @@
+#! /bin/bash -e
+# Generate mp_mbedtls_errors.c and build the tester app
+./do-mp.sh
+cc -o tester -I../mbedtls/include/ mp_mbedtls_errors.c tester.c

lib/mbedtls_errors/error.fmt

@@ -0,0 +1,165 @@
+/*
+ *  Error message information
+ *
+ *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
+ *  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.
+ *
+ *  This file is part of mbed TLS (https://tls.mbed.org)
+ */
+
+#if !defined(MBEDTLS_CONFIG_FILE)
+#include "mbedtls/config.h"
+#else
+#include MBEDTLS_CONFIG_FILE
+#endif
+
+#if defined(MBEDTLS_ERROR_C) || defined(MBEDTLS_ERROR_STRERROR_DUMMY)
+#include "mbedtls/error.h"
+#include <string.h>
+#endif
+
+#if defined(MBEDTLS_PLATFORM_C)
+#include "mbedtls/platform.h"
+#else
+#define mbedtls_snprintf snprintf
+#define mbedtls_time_t   time_t
+#endif
+
+#if defined(MBEDTLS_ERROR_C)
+
+#include <stdio.h>
+
+HEADER_INCLUDED
+
+// Error code table type
+struct ssl_errs {
+    int16_t errnum;
+    const char *errstr;
+};
+
+// Table of high level error codes
+static const struct ssl_errs mbedtls_high_level_error_tab[] = {
+// BEGIN generated code
+HIGH_LEVEL_CODE_CHECKS
+// END generated code
+};
+
+static const struct ssl_errs mbedtls_low_level_error_tab[] = {
+// Low level error codes
+//
+// BEGIN generated code
+LOW_LEVEL_CODE_CHECKS
+// END generated code
+};
+
+static const char *mbedtls_err_prefix = "MBEDTLS_ERR_";
+#define MBEDTLS_ERR_PREFIX_LEN ( sizeof("MBEDTLS_ERR_")-1 )
+
+// copy error text into buffer, ensure null termination, return strlen of result
+static size_t mbedtls_err_to_str(int err, const struct ssl_errs tab[], int tab_len, char *buf, size_t buflen) {
+    if (buflen == 0) return 0;
+
+    // prefix for all error names
+    strncpy(buf, mbedtls_err_prefix, buflen);
+    if (buflen <= MBEDTLS_ERR_PREFIX_LEN+1) {
+        buf[buflen-1] = 0;
+        return buflen-1;
+    }
+
+    // append error name from table
+    for (int i = 0; i < tab_len; i++) {
+        if (tab[i].errnum == err) {
+            strncpy(buf+MBEDTLS_ERR_PREFIX_LEN, tab[i].errstr, buflen-MBEDTLS_ERR_PREFIX_LEN);
+            buf[buflen-1] = 0;
+            return strlen(buf);
+        }
+    }
+
+    mbedtls_snprintf(buf+MBEDTLS_ERR_PREFIX_LEN, buflen-MBEDTLS_ERR_PREFIX_LEN, "UNKNOWN (0x%04X)",
+            err);
+    return strlen(buf);
+}
+
+#define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
+
+void mbedtls_strerror(int ret, char *buf, size_t buflen) {
+    int use_ret;
+
+    if (buflen == 0) return;
+
+    buf[buflen-1] = 0;
+
+    if (ret < 0) ret = -ret;
+
+    //
+    // High-level error codes
+    //
+    uint8_t got_hl = (ret & 0xFF80) != 0;
+    if (got_hl) {
+        use_ret = ret & 0xFF80;
+
+        // special case
+#if defined(MBEDTLS_SSL_TLS_C)
+        if (use_ret == -(MBEDTLS_ERR_SSL_FATAL_ALERT_MESSAGE)) {
+            strncpy(buf, "MBEDTLS_ERR_SSL_FATAL_ALERT_MESSAGE", buflen);
+            buf[buflen-1] = 0;
+            return;
+        }
+#endif
+
+        size_t len = mbedtls_err_to_str(use_ret, mbedtls_high_level_error_tab,
+                ARRAY_SIZE(mbedtls_high_level_error_tab), buf, buflen);
+
+        buf += len;
+        buflen -= len;
+        if (buflen == 0) return;
+    }
+
+    //
+    // Low-level error codes
+    //
+    use_ret = ret & ~0xFF80;
+
+    if (use_ret == 0) return;
+
+    // If high level code is present, make a concatenation between both error strings.
+    if (got_hl) {
+        if (buflen < 2) return;
+        *buf++ = '+';
+        buflen--;
+    }
+
+    mbedtls_err_to_str(use_ret, mbedtls_low_level_error_tab,
+            ARRAY_SIZE(mbedtls_low_level_error_tab), buf, buflen);
+}
+
+#else /* MBEDTLS_ERROR_C */
+
+#if defined(MBEDTLS_ERROR_STRERROR_DUMMY)
+
+/*
+ * Provide an non-function in case MBEDTLS_ERROR_C is not defined
+ */
+void mbedtls_strerror( int ret, char *buf, size_t buflen )
+{
+    ((void) ret);
+
+    if( buflen > 0 )
+        buf[0] = '\0';
+}
+
+#endif /* MBEDTLS_ERROR_STRERROR_DUMMY */
+
+#endif /* MBEDTLS_ERROR_C */

lib/mbedtls_errors/generate_errors.diff

@@ -0,0 +1,22 @@
+--- generate_errors_orig.pl	2020-06-20 08:40:38.819060379 -0700
++++ generate_errors.pl	2020-06-20 08:47:26.511163591 -0700
+@@ -162,16 +162,12 @@
+ 
+     if ($error_name eq "MBEDTLS_ERR_SSL_FATAL_ALERT_MESSAGE")
+     {
+-        ${$code_check} .= "${white_space}if( use_ret == -($error_name) )\n".
+-                          "${white_space}\{\n".
+-                          "${white_space}    mbedtls_snprintf( buf, buflen, \"$module_name - $description\" );\n".
+-                          "${white_space}    return;\n".
+-                          "${white_space}}\n"
++        # no-op, this case is hard-coded in error.fmt
+     }
+     else
+     {
+-        ${$code_check} .= "${white_space}if( use_ret == -($error_name) )\n".
+-                          "${white_space}    mbedtls_snprintf( buf, buflen, \"$module_name - $description\" );\n"
++         my $error_text = $error_name =~ s/^MBEDTLS_ERR_//r;
++         ${$code_check} .= "${white_space}{ -($error_name), \"$error_text\" },\n"
+     }
+ };
+ 

lib/mbedtls_errors/mp_mbedtls_errors.c

@@ -0,0 +1,705 @@
+/*
+ *  Error message information
+ *
+ *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
+ *  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.
+ *
+ *  This file is part of mbed TLS (https://tls.mbed.org)
+ */
+
+#if !defined(MBEDTLS_CONFIG_FILE)
+#include "mbedtls/config.h"
+#else
+#include MBEDTLS_CONFIG_FILE
+#endif
+
+#if defined(MBEDTLS_ERROR_C) || defined(MBEDTLS_ERROR_STRERROR_DUMMY)
+#include "mbedtls/error.h"
+#include <string.h>
+#endif
+
+#if defined(MBEDTLS_PLATFORM_C)
+#include "mbedtls/platform.h"
+#else
+#define mbedtls_snprintf snprintf
+#define mbedtls_time_t   time_t
+#endif
+
+#if defined(MBEDTLS_ERROR_C)
+
+#include <stdio.h>
+
+#if defined(MBEDTLS_AES_C)
+#include "mbedtls/aes.h"
+#endif
+
+#if defined(MBEDTLS_ARC4_C)
+#include "mbedtls/arc4.h"
+#endif
+
+#if defined(MBEDTLS_ARIA_C)
+#include "mbedtls/aria.h"
+#endif
+
+#if defined(MBEDTLS_BASE64_C)
+#include "mbedtls/base64.h"
+#endif
+
+#if defined(MBEDTLS_BIGNUM_C)
+#include "mbedtls/bignum.h"
+#endif
+
+#if defined(MBEDTLS_BLOWFISH_C)
+#include "mbedtls/blowfish.h"
+#endif
+
+#if defined(MBEDTLS_CAMELLIA_C)
+#include "mbedtls/camellia.h"
+#endif
+
+#if defined(MBEDTLS_CCM_C)
+#include "mbedtls/ccm.h"
+#endif
+
+#if defined(MBEDTLS_CHACHA20_C)
+#include "mbedtls/chacha20.h"
+#endif
+
+#if defined(MBEDTLS_CHACHAPOLY_C)
+#include "mbedtls/chachapoly.h"
+#endif
+
+#if defined(MBEDTLS_CIPHER_C)
+#include "mbedtls/cipher.h"
+#endif
+
+#if defined(MBEDTLS_CMAC_C)
+#include "mbedtls/cmac.h"
+#endif
+
+#if defined(MBEDTLS_CTR_DRBG_C)
+#include "mbedtls/ctr_drbg.h"
+#endif
+
+#if defined(MBEDTLS_DES_C)
+#include "mbedtls/des.h"
+#endif
+
+#if defined(MBEDTLS_DHM_C)
+#include "mbedtls/dhm.h"
+#endif
+
+#if defined(MBEDTLS_ECP_C)
+#include "mbedtls/ecp.h"
+#endif
+
+#if defined(MBEDTLS_ENTROPY_C)
+#include "mbedtls/entropy.h"
+#endif
+
+#if defined(MBEDTLS_GCM_C)
+#include "mbedtls/gcm.h"
+#endif
+
+#if defined(MBEDTLS_HKDF_C)
+#include "mbedtls/hkdf.h"
+#endif
+
+#if defined(MBEDTLS_HMAC_DRBG_C)
+#include "mbedtls/hmac_drbg.h"
+#endif
+
+#if defined(MBEDTLS_MD_C)
+#include "mbedtls/md.h"
+#endif
+
+#if defined(MBEDTLS_MD2_C)
+#include "mbedtls/md2.h"
+#endif
+
+#if defined(MBEDTLS_MD4_C)
+#include "mbedtls/md4.h"
+#endif
+
+#if defined(MBEDTLS_MD5_C)
+#include "mbedtls/md5.h"
+#endif
+
+#if defined(MBEDTLS_NET_C)
+#include "mbedtls/net_sockets.h"
+#endif
+
+#if defined(MBEDTLS_OID_C)
+#include "mbedtls/oid.h"
+#endif
+
+#if defined(MBEDTLS_PADLOCK_C)
+#include "mbedtls/padlock.h"
+#endif
+
+#if defined(MBEDTLS_PEM_PARSE_C) || defined(MBEDTLS_PEM_WRITE_C)
+#include "mbedtls/pem.h"
+#endif
+
+#if defined(MBEDTLS_PK_C)
+#include "mbedtls/pk.h"
+#endif
+
+#if defined(MBEDTLS_PKCS12_C)
+#include "mbedtls/pkcs12.h"
+#endif
+
+#if defined(MBEDTLS_PKCS5_C)
+#include "mbedtls/pkcs5.h"
+#endif
+
+#if defined(MBEDTLS_PLATFORM_C)
+#include "mbedtls/platform.h"
+#endif
+
+#if defined(MBEDTLS_POLY1305_C)
+#include "mbedtls/poly1305.h"
+#endif
+
+#if defined(MBEDTLS_RIPEMD160_C)
+#include "mbedtls/ripemd160.h"
+#endif
+
+#if defined(MBEDTLS_RSA_C)
+#include "mbedtls/rsa.h"
+#endif
+
+#if defined(MBEDTLS_SHA1_C)
+#include "mbedtls/sha1.h"
+#endif
+
+#if defined(MBEDTLS_SHA256_C)
+#include "mbedtls/sha256.h"
+#endif
+
+#if defined(MBEDTLS_SHA512_C)
+#include "mbedtls/sha512.h"
+#endif
+
+#if defined(MBEDTLS_SSL_TLS_C)
+#include "mbedtls/ssl.h"
+#endif
+
+#if defined(MBEDTLS_THREADING_C)
+#include "mbedtls/threading.h"
+#endif
+
+#if defined(MBEDTLS_X509_USE_C) || defined(MBEDTLS_X509_CREATE_C)
+#include "mbedtls/x509.h"
+#endif
+
+#if defined(MBEDTLS_XTEA_C)
+#include "mbedtls/xtea.h"
+#endif
+
+
+// Error code table type
+struct ssl_errs {
+    int16_t errnum;
+    const char *errstr;
+};
+
+// Table of high level error codes
+static const struct ssl_errs mbedtls_high_level_error_tab[] = {
+// BEGIN generated code
+#if defined(MBEDTLS_CIPHER_C)
+        { -(MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE), "CIPHER_FEATURE_UNAVAILABLE" },
+        { -(MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA), "CIPHER_BAD_INPUT_DATA" },
+        { -(MBEDTLS_ERR_CIPHER_ALLOC_FAILED), "CIPHER_ALLOC_FAILED" },
+        { -(MBEDTLS_ERR_CIPHER_INVALID_PADDING), "CIPHER_INVALID_PADDING" },
+        { -(MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED), "CIPHER_FULL_BLOCK_EXPECTED" },
+        { -(MBEDTLS_ERR_CIPHER_AUTH_FAILED), "CIPHER_AUTH_FAILED" },
+        { -(MBEDTLS_ERR_CIPHER_INVALID_CONTEXT), "CIPHER_INVALID_CONTEXT" },
+        { -(MBEDTLS_ERR_CIPHER_HW_ACCEL_FAILED), "CIPHER_HW_ACCEL_FAILED" },
+#endif /* MBEDTLS_CIPHER_C */
+
+#if defined(MBEDTLS_DHM_C)
+        { -(MBEDTLS_ERR_DHM_BAD_INPUT_DATA), "DHM_BAD_INPUT_DATA" },
+        { -(MBEDTLS_ERR_DHM_READ_PARAMS_FAILED), "DHM_READ_PARAMS_FAILED" },
+        { -(MBEDTLS_ERR_DHM_MAKE_PARAMS_FAILED), "DHM_MAKE_PARAMS_FAILED" },
+        { -(MBEDTLS_ERR_DHM_READ_PUBLIC_FAILED), "DHM_READ_PUBLIC_FAILED" },
+        { -(MBEDTLS_ERR_DHM_MAKE_PUBLIC_FAILED), "DHM_MAKE_PUBLIC_FAILED" },
+        { -(MBEDTLS_ERR_DHM_CALC_SECRET_FAILED), "DHM_CALC_SECRET_FAILED" },
+        { -(MBEDTLS_ERR_DHM_INVALID_FORMAT), "DHM_INVALID_FORMAT" },
+        { -(MBEDTLS_ERR_DHM_ALLOC_FAILED), "DHM_ALLOC_FAILED" },
+        { -(MBEDTLS_ERR_DHM_FILE_IO_ERROR), "DHM_FILE_IO_ERROR" },
+        { -(MBEDTLS_ERR_DHM_HW_ACCEL_FAILED), "DHM_HW_ACCEL_FAILED" },
+        { -(MBEDTLS_ERR_DHM_SET_GROUP_FAILED), "DHM_SET_GROUP_FAILED" },
+#endif /* MBEDTLS_DHM_C */
+
+#if defined(MBEDTLS_ECP_C)
+        { -(MBEDTLS_ERR_ECP_BAD_INPUT_DATA), "ECP_BAD_INPUT_DATA" },
+        { -(MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL), "ECP_BUFFER_TOO_SMALL" },
+        { -(MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE), "ECP_FEATURE_UNAVAILABLE" },
+        { -(MBEDTLS_ERR_ECP_VERIFY_FAILED), "ECP_VERIFY_FAILED" },
+        { -(MBEDTLS_ERR_ECP_ALLOC_FAILED), "ECP_ALLOC_FAILED" },
+        { -(MBEDTLS_ERR_ECP_RANDOM_FAILED), "ECP_RANDOM_FAILED" },
+        { -(MBEDTLS_ERR_ECP_INVALID_KEY), "ECP_INVALID_KEY" },
+        { -(MBEDTLS_ERR_ECP_SIG_LEN_MISMATCH), "ECP_SIG_LEN_MISMATCH" },
+        { -(MBEDTLS_ERR_ECP_HW_ACCEL_FAILED), "ECP_HW_ACCEL_FAILED" },
+        { -(MBEDTLS_ERR_ECP_IN_PROGRESS), "ECP_IN_PROGRESS" },
+#endif /* MBEDTLS_ECP_C */
+
+#if defined(MBEDTLS_MD_C)
+        { -(MBEDTLS_ERR_MD_FEATURE_UNAVAILABLE), "MD_FEATURE_UNAVAILABLE" },
+        { -(MBEDTLS_ERR_MD_BAD_INPUT_DATA), "MD_BAD_INPUT_DATA" },
+        { -(MBEDTLS_ERR_MD_ALLOC_FAILED), "MD_ALLOC_FAILED" },
+        { -(MBEDTLS_ERR_MD_FILE_IO_ERROR), "MD_FILE_IO_ERROR" },
+        { -(MBEDTLS_ERR_MD_HW_ACCEL_FAILED), "MD_HW_ACCEL_FAILED" },
+#endif /* MBEDTLS_MD_C */
+
+#if defined(MBEDTLS_PEM_PARSE_C) || defined(MBEDTLS_PEM_WRITE_C)
+        { -(MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT), "PEM_NO_HEADER_FOOTER_PRESENT" },
+        { -(MBEDTLS_ERR_PEM_INVALID_DATA), "PEM_INVALID_DATA" },
+        { -(MBEDTLS_ERR_PEM_ALLOC_FAILED), "PEM_ALLOC_FAILED" },
+        { -(MBEDTLS_ERR_PEM_INVALID_ENC_IV), "PEM_INVALID_ENC_IV" },
+        { -(MBEDTLS_ERR_PEM_UNKNOWN_ENC_ALG), "PEM_UNKNOWN_ENC_ALG" },
+        { -(MBEDTLS_ERR_PEM_PASSWORD_REQUIRED), "PEM_PASSWORD_REQUIRED" },
+        { -(MBEDTLS_ERR_PEM_PASSWORD_MISMATCH), "PEM_PASSWORD_MISMATCH" },
+        { -(MBEDTLS_ERR_PEM_FEATURE_UNAVAILABLE), "PEM_FEATURE_UNAVAILABLE" },
+        { -(MBEDTLS_ERR_PEM_BAD_INPUT_DATA), "PEM_BAD_INPUT_DATA" },
+#endif /* MBEDTLS_PEM_PARSE_C || MBEDTLS_PEM_WRITE_C */
+
+#if defined(MBEDTLS_PK_C)
+        { -(MBEDTLS_ERR_PK_ALLOC_FAILED), "PK_ALLOC_FAILED" },
+        { -(MBEDTLS_ERR_PK_TYPE_MISMATCH), "PK_TYPE_MISMATCH" },
+        { -(MBEDTLS_ERR_PK_BAD_INPUT_DATA), "PK_BAD_INPUT_DATA" },
+        { -(MBEDTLS_ERR_PK_FILE_IO_ERROR), "PK_FILE_IO_ERROR" },
+        { -(MBEDTLS_ERR_PK_KEY_INVALID_VERSION), "PK_KEY_INVALID_VERSION" },
+        { -(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT), "PK_KEY_INVALID_FORMAT" },
+        { -(MBEDTLS_ERR_PK_UNKNOWN_PK_ALG), "PK_UNKNOWN_PK_ALG" },
+        { -(MBEDTLS_ERR_PK_PASSWORD_REQUIRED), "PK_PASSWORD_REQUIRED" },
+        { -(MBEDTLS_ERR_PK_PASSWORD_MISMATCH), "PK_PASSWORD_MISMATCH" },
+        { -(MBEDTLS_ERR_PK_INVALID_PUBKEY), "PK_INVALID_PUBKEY" },
+        { -(MBEDTLS_ERR_PK_INVALID_ALG), "PK_INVALID_ALG" },
+        { -(MBEDTLS_ERR_PK_UNKNOWN_NAMED_CURVE), "PK_UNKNOWN_NAMED_CURVE" },
+        { -(MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE), "PK_FEATURE_UNAVAILABLE" },
+        { -(MBEDTLS_ERR_PK_SIG_LEN_MISMATCH), "PK_SIG_LEN_MISMATCH" },
+        { -(MBEDTLS_ERR_PK_HW_ACCEL_FAILED), "PK_HW_ACCEL_FAILED" },
+#endif /* MBEDTLS_PK_C */
+
+#if defined(MBEDTLS_PKCS12_C)
+        { -(MBEDTLS_ERR_PKCS12_BAD_INPUT_DATA), "PKCS12_BAD_INPUT_DATA" },
+        { -(MBEDTLS_ERR_PKCS12_FEATURE_UNAVAILABLE), "PKCS12_FEATURE_UNAVAILABLE" },
+        { -(MBEDTLS_ERR_PKCS12_PBE_INVALID_FORMAT), "PKCS12_PBE_INVALID_FORMAT" },
+        { -(MBEDTLS_ERR_PKCS12_PASSWORD_MISMATCH), "PKCS12_PASSWORD_MISMATCH" },
+#endif /* MBEDTLS_PKCS12_C */
+
+#if defined(MBEDTLS_PKCS5_C)
+        { -(MBEDTLS_ERR_PKCS5_BAD_INPUT_DATA), "PKCS5_BAD_INPUT_DATA" },
+        { -(MBEDTLS_ERR_PKCS5_INVALID_FORMAT), "PKCS5_INVALID_FORMAT" },
+        { -(MBEDTLS_ERR_PKCS5_FEATURE_UNAVAILABLE), "PKCS5_FEATURE_UNAVAILABLE" },
+        { -(MBEDTLS_ERR_PKCS5_PASSWORD_MISMATCH), "PKCS5_PASSWORD_MISMATCH" },
+#endif /* MBEDTLS_PKCS5_C */
+
+#if defined(MBEDTLS_RSA_C)
+        { -(MBEDTLS_ERR_RSA_BAD_INPUT_DATA), "RSA_BAD_INPUT_DATA" },
+        { -(MBEDTLS_ERR_RSA_INVALID_PADDING), "RSA_INVALID_PADDING" },
+        { -(MBEDTLS_ERR_RSA_KEY_GEN_FAILED), "RSA_KEY_GEN_FAILED" },
+        { -(MBEDTLS_ERR_RSA_KEY_CHECK_FAILED), "RSA_KEY_CHECK_FAILED" },
+        { -(MBEDTLS_ERR_RSA_PUBLIC_FAILED), "RSA_PUBLIC_FAILED" },
+        { -(MBEDTLS_ERR_RSA_PRIVATE_FAILED), "RSA_PRIVATE_FAILED" },
+        { -(MBEDTLS_ERR_RSA_VERIFY_FAILED), "RSA_VERIFY_FAILED" },
+        { -(MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE), "RSA_OUTPUT_TOO_LARGE" },
+        { -(MBEDTLS_ERR_RSA_RNG_FAILED), "RSA_RNG_FAILED" },
+        { -(MBEDTLS_ERR_RSA_UNSUPPORTED_OPERATION), "RSA_UNSUPPORTED_OPERATION" },
+        { -(MBEDTLS_ERR_RSA_HW_ACCEL_FAILED), "RSA_HW_ACCEL_FAILED" },
+#endif /* MBEDTLS_RSA_C */
+
+#if defined(MBEDTLS_SSL_TLS_C)
+        { -(MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE), "SSL_FEATURE_UNAVAILABLE" },
+        { -(MBEDTLS_ERR_SSL_BAD_INPUT_DATA), "SSL_BAD_INPUT_DATA" },
+        { -(MBEDTLS_ERR_SSL_INVALID_MAC), "SSL_INVALID_MAC" },
+        { -(MBEDTLS_ERR_SSL_INVALID_RECORD), "SSL_INVALID_RECORD" },
+        { -(MBEDTLS_ERR_SSL_CONN_EOF), "SSL_CONN_EOF" },
+        { -(MBEDTLS_ERR_SSL_UNKNOWN_CIPHER), "SSL_UNKNOWN_CIPHER" },
+        { -(MBEDTLS_ERR_SSL_NO_CIPHER_CHOSEN), "SSL_NO_CIPHER_CHOSEN" },
+        { -(MBEDTLS_ERR_SSL_NO_RNG), "SSL_NO_RNG" },
+        { -(MBEDTLS_ERR_SSL_NO_CLIENT_CERTIFICATE), "SSL_NO_CLIENT_CERTIFICATE" },
+        { -(MBEDTLS_ERR_SSL_CERTIFICATE_TOO_LARGE), "SSL_CERTIFICATE_TOO_LARGE" },
+        { -(MBEDTLS_ERR_SSL_CERTIFICATE_REQUIRED), "SSL_CERTIFICATE_REQUIRED" },
+        { -(MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED), "SSL_PRIVATE_KEY_REQUIRED" },
+        { -(MBEDTLS_ERR_SSL_CA_CHAIN_REQUIRED), "SSL_CA_CHAIN_REQUIRED" },
+        { -(MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE), "SSL_UNEXPECTED_MESSAGE" },
+        { -(MBEDTLS_ERR_SSL_PEER_VERIFY_FAILED), "SSL_PEER_VERIFY_FAILED" },
+        { -(MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY), "SSL_PEER_CLOSE_NOTIFY" },
+        { -(MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO), "SSL_BAD_HS_CLIENT_HELLO" },
+        { -(MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO), "SSL_BAD_HS_SERVER_HELLO" },
+        { -(MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE), "SSL_BAD_HS_CERTIFICATE" },
+        { -(MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_REQUEST), "SSL_BAD_HS_CERTIFICATE_REQUEST" },
+        { -(MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE), "SSL_BAD_HS_SERVER_KEY_EXCHANGE" },
+        { -(MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO_DONE), "SSL_BAD_HS_SERVER_HELLO_DONE" },
+        { -(MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE), "SSL_BAD_HS_CLIENT_KEY_EXCHANGE" },
+        { -(MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP), "SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP" },
+        { -(MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_CS), "SSL_BAD_HS_CLIENT_KEY_EXCHANGE_CS" },
+        { -(MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY), "SSL_BAD_HS_CERTIFICATE_VERIFY" },
+        { -(MBEDTLS_ERR_SSL_BAD_HS_CHANGE_CIPHER_SPEC), "SSL_BAD_HS_CHANGE_CIPHER_SPEC" },
+        { -(MBEDTLS_ERR_SSL_BAD_HS_FINISHED), "SSL_BAD_HS_FINISHED" },
+        { -(MBEDTLS_ERR_SSL_ALLOC_FAILED), "SSL_ALLOC_FAILED" },
+        { -(MBEDTLS_ERR_SSL_HW_ACCEL_FAILED), "SSL_HW_ACCEL_FAILED" },
+        { -(MBEDTLS_ERR_SSL_HW_ACCEL_FALLTHROUGH), "SSL_HW_ACCEL_FALLTHROUGH" },
+        { -(MBEDTLS_ERR_SSL_COMPRESSION_FAILED), "SSL_COMPRESSION_FAILED" },
+        { -(MBEDTLS_ERR_SSL_BAD_HS_PROTOCOL_VERSION), "SSL_BAD_HS_PROTOCOL_VERSION" },
+        { -(MBEDTLS_ERR_SSL_BAD_HS_NEW_SESSION_TICKET), "SSL_BAD_HS_NEW_SESSION_TICKET" },
+        { -(MBEDTLS_ERR_SSL_SESSION_TICKET_EXPIRED), "SSL_SESSION_TICKET_EXPIRED" },
+        { -(MBEDTLS_ERR_SSL_PK_TYPE_MISMATCH), "SSL_PK_TYPE_MISMATCH" },
+        { -(MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY), "SSL_UNKNOWN_IDENTITY" },
+        { -(MBEDTLS_ERR_SSL_INTERNAL_ERROR), "SSL_INTERNAL_ERROR" },
+        { -(MBEDTLS_ERR_SSL_COUNTER_WRAPPING), "SSL_COUNTER_WRAPPING" },
+        { -(MBEDTLS_ERR_SSL_WAITING_SERVER_HELLO_RENEGO), "SSL_WAITING_SERVER_HELLO_RENEGO" },
+        { -(MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED), "SSL_HELLO_VERIFY_REQUIRED" },
+        { -(MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL), "SSL_BUFFER_TOO_SMALL" },
+        { -(MBEDTLS_ERR_SSL_NO_USABLE_CIPHERSUITE), "SSL_NO_USABLE_CIPHERSUITE" },
+        { -(MBEDTLS_ERR_SSL_WANT_READ), "SSL_WANT_READ" },
+        { -(MBEDTLS_ERR_SSL_WANT_WRITE), "SSL_WANT_WRITE" },
+        { -(MBEDTLS_ERR_SSL_TIMEOUT), "SSL_TIMEOUT" },
+        { -(MBEDTLS_ERR_SSL_CLIENT_RECONNECT), "SSL_CLIENT_RECONNECT" },
+        { -(MBEDTLS_ERR_SSL_UNEXPECTED_RECORD), "SSL_UNEXPECTED_RECORD" },
+        { -(MBEDTLS_ERR_SSL_NON_FATAL), "SSL_NON_FATAL" },
+        { -(MBEDTLS_ERR_SSL_INVALID_VERIFY_HASH), "SSL_INVALID_VERIFY_HASH" },
+        { -(MBEDTLS_ERR_SSL_CONTINUE_PROCESSING), "SSL_CONTINUE_PROCESSING" },
+        { -(MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS), "SSL_ASYNC_IN_PROGRESS" },
+        { -(MBEDTLS_ERR_SSL_EARLY_MESSAGE), "SSL_EARLY_MESSAGE" },
+        { -(MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS), "SSL_CRYPTO_IN_PROGRESS" },
+#endif /* MBEDTLS_SSL_TLS_C */
+
+#if defined(MBEDTLS_X509_USE_C) || defined(MBEDTLS_X509_CREATE_C)
+        { -(MBEDTLS_ERR_X509_FEATURE_UNAVAILABLE), "X509_FEATURE_UNAVAILABLE" },
+        { -(MBEDTLS_ERR_X509_UNKNOWN_OID), "X509_UNKNOWN_OID" },
+        { -(MBEDTLS_ERR_X509_INVALID_FORMAT), "X509_INVALID_FORMAT" },
+        { -(MBEDTLS_ERR_X509_INVALID_VERSION), "X509_INVALID_VERSION" },
+        { -(MBEDTLS_ERR_X509_INVALID_SERIAL), "X509_INVALID_SERIAL" },
+        { -(MBEDTLS_ERR_X509_INVALID_ALG), "X509_INVALID_ALG" },
+        { -(MBEDTLS_ERR_X509_INVALID_NAME), "X509_INVALID_NAME" },
+        { -(MBEDTLS_ERR_X509_INVALID_DATE), "X509_INVALID_DATE" },
+        { -(MBEDTLS_ERR_X509_INVALID_SIGNATURE), "X509_INVALID_SIGNATURE" },
+        { -(MBEDTLS_ERR_X509_INVALID_EXTENSIONS), "X509_INVALID_EXTENSIONS" },
+        { -(MBEDTLS_ERR_X509_UNKNOWN_VERSION), "X509_UNKNOWN_VERSION" },
+        { -(MBEDTLS_ERR_X509_UNKNOWN_SIG_ALG), "X509_UNKNOWN_SIG_ALG" },
+        { -(MBEDTLS_ERR_X509_SIG_MISMATCH), "X509_SIG_MISMATCH" },
+        { -(MBEDTLS_ERR_X509_CERT_VERIFY_FAILED), "X509_CERT_VERIFY_FAILED" },
+        { -(MBEDTLS_ERR_X509_CERT_UNKNOWN_FORMAT), "X509_CERT_UNKNOWN_FORMAT" },
+        { -(MBEDTLS_ERR_X509_BAD_INPUT_DATA), "X509_BAD_INPUT_DATA" },
+        { -(MBEDTLS_ERR_X509_ALLOC_FAILED), "X509_ALLOC_FAILED" },
+        { -(MBEDTLS_ERR_X509_FILE_IO_ERROR), "X509_FILE_IO_ERROR" },
+        { -(MBEDTLS_ERR_X509_BUFFER_TOO_SMALL), "X509_BUFFER_TOO_SMALL" },
+        { -(MBEDTLS_ERR_X509_FATAL_ERROR), "X509_FATAL_ERROR" },
+#endif /* MBEDTLS_X509_USE_C || MBEDTLS_X509_CREATE_C */
+// END generated code
+};
+
+static const struct ssl_errs mbedtls_low_level_error_tab[] = {
+// Low level error codes
+//
+// BEGIN generated code
+#if defined(MBEDTLS_AES_C)
+    { -(MBEDTLS_ERR_AES_INVALID_KEY_LENGTH), "AES_INVALID_KEY_LENGTH" },
+    { -(MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH), "AES_INVALID_INPUT_LENGTH" },
+    { -(MBEDTLS_ERR_AES_BAD_INPUT_DATA), "AES_BAD_INPUT_DATA" },
+    { -(MBEDTLS_ERR_AES_FEATURE_UNAVAILABLE), "AES_FEATURE_UNAVAILABLE" },
+    { -(MBEDTLS_ERR_AES_HW_ACCEL_FAILED), "AES_HW_ACCEL_FAILED" },
+#endif /* MBEDTLS_AES_C */
+
+#if defined(MBEDTLS_ARC4_C)
+    { -(MBEDTLS_ERR_ARC4_HW_ACCEL_FAILED), "ARC4_HW_ACCEL_FAILED" },
+#endif /* MBEDTLS_ARC4_C */
+
+#if defined(MBEDTLS_ARIA_C)
+    { -(MBEDTLS_ERR_ARIA_BAD_INPUT_DATA), "ARIA_BAD_INPUT_DATA" },
+    { -(MBEDTLS_ERR_ARIA_INVALID_INPUT_LENGTH), "ARIA_INVALID_INPUT_LENGTH" },
+    { -(MBEDTLS_ERR_ARIA_FEATURE_UNAVAILABLE), "ARIA_FEATURE_UNAVAILABLE" },
+    { -(MBEDTLS_ERR_ARIA_HW_ACCEL_FAILED), "ARIA_HW_ACCEL_FAILED" },
+#endif /* MBEDTLS_ARIA_C */
+
+#if defined(MBEDTLS_ASN1_PARSE_C)
+    { -(MBEDTLS_ERR_ASN1_OUT_OF_DATA), "ASN1_OUT_OF_DATA" },
+    { -(MBEDTLS_ERR_ASN1_UNEXPECTED_TAG), "ASN1_UNEXPECTED_TAG" },
+    { -(MBEDTLS_ERR_ASN1_INVALID_LENGTH), "ASN1_INVALID_LENGTH" },
+    { -(MBEDTLS_ERR_ASN1_LENGTH_MISMATCH), "ASN1_LENGTH_MISMATCH" },
+    { -(MBEDTLS_ERR_ASN1_INVALID_DATA), "ASN1_INVALID_DATA" },
+    { -(MBEDTLS_ERR_ASN1_ALLOC_FAILED), "ASN1_ALLOC_FAILED" },
+    { -(MBEDTLS_ERR_ASN1_BUF_TOO_SMALL), "ASN1_BUF_TOO_SMALL" },
+#endif /* MBEDTLS_ASN1_PARSE_C */
+
+#if defined(MBEDTLS_BASE64_C)
+    { -(MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL), "BASE64_BUFFER_TOO_SMALL" },
+    { -(MBEDTLS_ERR_BASE64_INVALID_CHARACTER), "BASE64_INVALID_CHARACTER" },
+#endif /* MBEDTLS_BASE64_C */
+
+#if defined(MBEDTLS_BIGNUM_C)
+    { -(MBEDTLS_ERR_MPI_FILE_IO_ERROR), "MPI_FILE_IO_ERROR" },
+    { -(MBEDTLS_ERR_MPI_BAD_INPUT_DATA), "MPI_BAD_INPUT_DATA" },
+    { -(MBEDTLS_ERR_MPI_INVALID_CHARACTER), "MPI_INVALID_CHARACTER" },
+    { -(MBEDTLS_ERR_MPI_BUFFER_TOO_SMALL), "MPI_BUFFER_TOO_SMALL" },
+    { -(MBEDTLS_ERR_MPI_NEGATIVE_VALUE), "MPI_NEGATIVE_VALUE" },
+    { -(MBEDTLS_ERR_MPI_DIVISION_BY_ZERO), "MPI_DIVISION_BY_ZERO" },
+    { -(MBEDTLS_ERR_MPI_NOT_ACCEPTABLE), "MPI_NOT_ACCEPTABLE" },
+    { -(MBEDTLS_ERR_MPI_ALLOC_FAILED), "MPI_ALLOC_FAILED" },
+#endif /* MBEDTLS_BIGNUM_C */
+
+#if defined(MBEDTLS_BLOWFISH_C)
+    { -(MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA), "BLOWFISH_BAD_INPUT_DATA" },
+    { -(MBEDTLS_ERR_BLOWFISH_INVALID_INPUT_LENGTH), "BLOWFISH_INVALID_INPUT_LENGTH" },
+    { -(MBEDTLS_ERR_BLOWFISH_HW_ACCEL_FAILED), "BLOWFISH_HW_ACCEL_FAILED" },
+#endif /* MBEDTLS_BLOWFISH_C */
+
+#if defined(MBEDTLS_CAMELLIA_C)
+    { -(MBEDTLS_ERR_CAMELLIA_BAD_INPUT_DATA), "CAMELLIA_BAD_INPUT_DATA" },
+    { -(MBEDTLS_ERR_CAMELLIA_INVALID_INPUT_LENGTH), "CAMELLIA_INVALID_INPUT_LENGTH" },
+    { -(MBEDTLS_ERR_CAMELLIA_HW_ACCEL_FAILED), "CAMELLIA_HW_ACCEL_FAILED" },
+#endif /* MBEDTLS_CAMELLIA_C */
+
+#if defined(MBEDTLS_CCM_C)
+    { -(MBEDTLS_ERR_CCM_BAD_INPUT), "CCM_BAD_INPUT" },
+    { -(MBEDTLS_ERR_CCM_AUTH_FAILED), "CCM_AUTH_FAILED" },
+    { -(MBEDTLS_ERR_CCM_HW_ACCEL_FAILED), "CCM_HW_ACCEL_FAILED" },
+#endif /* MBEDTLS_CCM_C */
+
+#if defined(MBEDTLS_CHACHA20_C)
+    { -(MBEDTLS_ERR_CHACHA20_BAD_INPUT_DATA), "CHACHA20_BAD_INPUT_DATA" },
+    { -(MBEDTLS_ERR_CHACHA20_FEATURE_UNAVAILABLE), "CHACHA20_FEATURE_UNAVAILABLE" },
+    { -(MBEDTLS_ERR_CHACHA20_HW_ACCEL_FAILED), "CHACHA20_HW_ACCEL_FAILED" },
+#endif /* MBEDTLS_CHACHA20_C */
+
+#if defined(MBEDTLS_CHACHAPOLY_C)
+    { -(MBEDTLS_ERR_CHACHAPOLY_BAD_STATE), "CHACHAPOLY_BAD_STATE" },
+    { -(MBEDTLS_ERR_CHACHAPOLY_AUTH_FAILED), "CHACHAPOLY_AUTH_FAILED" },
+#endif /* MBEDTLS_CHACHAPOLY_C */
+
+#if defined(MBEDTLS_CMAC_C)
+    { -(MBEDTLS_ERR_CMAC_HW_ACCEL_FAILED), "CMAC_HW_ACCEL_FAILED" },
+#endif /* MBEDTLS_CMAC_C */
+
+#if defined(MBEDTLS_CTR_DRBG_C)
+    { -(MBEDTLS_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED), "CTR_DRBG_ENTROPY_SOURCE_FAILED" },
+    { -(MBEDTLS_ERR_CTR_DRBG_REQUEST_TOO_BIG), "CTR_DRBG_REQUEST_TOO_BIG" },
+    { -(MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG), "CTR_DRBG_INPUT_TOO_BIG" },
+    { -(MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR), "CTR_DRBG_FILE_IO_ERROR" },
+#endif /* MBEDTLS_CTR_DRBG_C */
+
+#if defined(MBEDTLS_DES_C)
+    { -(MBEDTLS_ERR_DES_INVALID_INPUT_LENGTH), "DES_INVALID_INPUT_LENGTH" },
+    { -(MBEDTLS_ERR_DES_HW_ACCEL_FAILED), "DES_HW_ACCEL_FAILED" },
+#endif /* MBEDTLS_DES_C */
+
+#if defined(MBEDTLS_ENTROPY_C)
+    { -(MBEDTLS_ERR_ENTROPY_SOURCE_FAILED), "ENTROPY_SOURCE_FAILED" },
+    { -(MBEDTLS_ERR_ENTROPY_MAX_SOURCES), "ENTROPY_MAX_SOURCES" },
+    { -(MBEDTLS_ERR_ENTROPY_NO_SOURCES_DEFINED), "ENTROPY_NO_SOURCES_DEFINED" },
+    { -(MBEDTLS_ERR_ENTROPY_NO_STRONG_SOURCE), "ENTROPY_NO_STRONG_SOURCE" },
+    { -(MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR), "ENTROPY_FILE_IO_ERROR" },
+#endif /* MBEDTLS_ENTROPY_C */
+
+#if defined(MBEDTLS_GCM_C)
+    { -(MBEDTLS_ERR_GCM_AUTH_FAILED), "GCM_AUTH_FAILED" },
+    { -(MBEDTLS_ERR_GCM_HW_ACCEL_FAILED), "GCM_HW_ACCEL_FAILED" },
+    { -(MBEDTLS_ERR_GCM_BAD_INPUT), "GCM_BAD_INPUT" },
+#endif /* MBEDTLS_GCM_C */
+
+#if defined(MBEDTLS_HKDF_C)
+    { -(MBEDTLS_ERR_HKDF_BAD_INPUT_DATA), "HKDF_BAD_INPUT_DATA" },
+#endif /* MBEDTLS_HKDF_C */
+
+#if defined(MBEDTLS_HMAC_DRBG_C)
+    { -(MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG), "HMAC_DRBG_REQUEST_TOO_BIG" },
+    { -(MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG), "HMAC_DRBG_INPUT_TOO_BIG" },
+    { -(MBEDTLS_ERR_HMAC_DRBG_FILE_IO_ERROR), "HMAC_DRBG_FILE_IO_ERROR" },
+    { -(MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED), "HMAC_DRBG_ENTROPY_SOURCE_FAILED" },
+#endif /* MBEDTLS_HMAC_DRBG_C */
+
+#if defined(MBEDTLS_MD2_C)
+    { -(MBEDTLS_ERR_MD2_HW_ACCEL_FAILED), "MD2_HW_ACCEL_FAILED" },
+#endif /* MBEDTLS_MD2_C */
+
+#if defined(MBEDTLS_MD4_C)
+    { -(MBEDTLS_ERR_MD4_HW_ACCEL_FAILED), "MD4_HW_ACCEL_FAILED" },
+#endif /* MBEDTLS_MD4_C */
+
+#if defined(MBEDTLS_MD5_C)
+    { -(MBEDTLS_ERR_MD5_HW_ACCEL_FAILED), "MD5_HW_ACCEL_FAILED" },
+#endif /* MBEDTLS_MD5_C */
+
+#if defined(MBEDTLS_NET_C)
+    { -(MBEDTLS_ERR_NET_SOCKET_FAILED), "NET_SOCKET_FAILED" },
+    { -(MBEDTLS_ERR_NET_CONNECT_FAILED), "NET_CONNECT_FAILED" },
+    { -(MBEDTLS_ERR_NET_BIND_FAILED), "NET_BIND_FAILED" },
+    { -(MBEDTLS_ERR_NET_LISTEN_FAILED), "NET_LISTEN_FAILED" },
+    { -(MBEDTLS_ERR_NET_ACCEPT_FAILED), "NET_ACCEPT_FAILED" },
+    { -(MBEDTLS_ERR_NET_RECV_FAILED), "NET_RECV_FAILED" },
+    { -(MBEDTLS_ERR_NET_SEND_FAILED), "NET_SEND_FAILED" },
+    { -(MBEDTLS_ERR_NET_CONN_RESET), "NET_CONN_RESET" },
+    { -(MBEDTLS_ERR_NET_UNKNOWN_HOST), "NET_UNKNOWN_HOST" },
+    { -(MBEDTLS_ERR_NET_BUFFER_TOO_SMALL), "NET_BUFFER_TOO_SMALL" },
+    { -(MBEDTLS_ERR_NET_INVALID_CONTEXT), "NET_INVALID_CONTEXT" },
+    { -(MBEDTLS_ERR_NET_POLL_FAILED), "NET_POLL_FAILED" },
+    { -(MBEDTLS_ERR_NET_BAD_INPUT_DATA), "NET_BAD_INPUT_DATA" },
+#endif /* MBEDTLS_NET_C */
+
+#if defined(MBEDTLS_OID_C)
+    { -(MBEDTLS_ERR_OID_NOT_FOUND), "OID_NOT_FOUND" },
+    { -(MBEDTLS_ERR_OID_BUF_TOO_SMALL), "OID_BUF_TOO_SMALL" },
+#endif /* MBEDTLS_OID_C */
+
+#if defined(MBEDTLS_PADLOCK_C)
+    { -(MBEDTLS_ERR_PADLOCK_DATA_MISALIGNED), "PADLOCK_DATA_MISALIGNED" },
+#endif /* MBEDTLS_PADLOCK_C */
+
+#if defined(MBEDTLS_PLATFORM_C)
+    { -(MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED), "PLATFORM_HW_ACCEL_FAILED" },
+    { -(MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED), "PLATFORM_FEATURE_UNSUPPORTED" },
+#endif /* MBEDTLS_PLATFORM_C */
+
+#if defined(MBEDTLS_POLY1305_C)
+    { -(MBEDTLS_ERR_POLY1305_BAD_INPUT_DATA), "POLY1305_BAD_INPUT_DATA" },
+    { -(MBEDTLS_ERR_POLY1305_FEATURE_UNAVAILABLE), "POLY1305_FEATURE_UNAVAILABLE" },
+    { -(MBEDTLS_ERR_POLY1305_HW_ACCEL_FAILED), "POLY1305_HW_ACCEL_FAILED" },
+#endif /* MBEDTLS_POLY1305_C */
+
+#if defined(MBEDTLS_RIPEMD160_C)
+    { -(MBEDTLS_ERR_RIPEMD160_HW_ACCEL_FAILED), "RIPEMD160_HW_ACCEL_FAILED" },
+#endif /* MBEDTLS_RIPEMD160_C */
+
+#if defined(MBEDTLS_SHA1_C)
+    { -(MBEDTLS_ERR_SHA1_HW_ACCEL_FAILED), "SHA1_HW_ACCEL_FAILED" },
+    { -(MBEDTLS_ERR_SHA1_BAD_INPUT_DATA), "SHA1_BAD_INPUT_DATA" },
+#endif /* MBEDTLS_SHA1_C */
+
+#if defined(MBEDTLS_SHA256_C)
+    { -(MBEDTLS_ERR_SHA256_HW_ACCEL_FAILED), "SHA256_HW_ACCEL_FAILED" },
+    { -(MBEDTLS_ERR_SHA256_BAD_INPUT_DATA), "SHA256_BAD_INPUT_DATA" },
+#endif /* MBEDTLS_SHA256_C */
+
+#if defined(MBEDTLS_SHA512_C)
+    { -(MBEDTLS_ERR_SHA512_HW_ACCEL_FAILED), "SHA512_HW_ACCEL_FAILED" },
+    { -(MBEDTLS_ERR_SHA512_BAD_INPUT_DATA), "SHA512_BAD_INPUT_DATA" },
+#endif /* MBEDTLS_SHA512_C */
+
+#if defined(MBEDTLS_THREADING_C)
+    { -(MBEDTLS_ERR_THREADING_FEATURE_UNAVAILABLE), "THREADING_FEATURE_UNAVAILABLE" },
+    { -(MBEDTLS_ERR_THREADING_BAD_INPUT_DATA), "THREADING_BAD_INPUT_DATA" },
+    { -(MBEDTLS_ERR_THREADING_MUTEX_ERROR), "THREADING_MUTEX_ERROR" },
+#endif /* MBEDTLS_THREADING_C */
+
+#if defined(MBEDTLS_XTEA_C)
+    { -(MBEDTLS_ERR_XTEA_INVALID_INPUT_LENGTH), "XTEA_INVALID_INPUT_LENGTH" },
+    { -(MBEDTLS_ERR_XTEA_HW_ACCEL_FAILED), "XTEA_HW_ACCEL_FAILED" },
+#endif /* MBEDTLS_XTEA_C */
+// END generated code
+};
+
+static const char *mbedtls_err_prefix = "MBEDTLS_ERR_";
+#define MBEDTLS_ERR_PREFIX_LEN ( sizeof("MBEDTLS_ERR_")-1 )
+
+// copy error text into buffer, ensure null termination, return strlen of result
+static size_t mbedtls_err_to_str(int err, const struct ssl_errs tab[], int tab_len, char *buf, size_t buflen) {
+    if (buflen == 0) return 0;
+
+    // prefix for all error names
+    strncpy(buf, mbedtls_err_prefix, buflen);
+    if (buflen <= MBEDTLS_ERR_PREFIX_LEN+1) {
+        buf[buflen-1] = 0;
+        return buflen-1;
+    }
+
+    // append error name from table
+    for (int i = 0; i < tab_len; i++) {
+        if (tab[i].errnum == err) {
+            strncpy(buf+MBEDTLS_ERR_PREFIX_LEN, tab[i].errstr, buflen-MBEDTLS_ERR_PREFIX_LEN);
+            buf[buflen-1] = 0;
+            return strlen(buf);
+        }
+    }
+
+    mbedtls_snprintf(buf+MBEDTLS_ERR_PREFIX_LEN, buflen-MBEDTLS_ERR_PREFIX_LEN, "UNKNOWN (0x%04X)",
+            err);
+    return strlen(buf);
+}
+
+#define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
+
+void mbedtls_strerror(int ret, char *buf, size_t buflen) {
+    int use_ret;
+
+    if (buflen == 0) return;
+
+    buf[buflen-1] = 0;
+
+    if (ret < 0) ret = -ret;
+
+    //
+    // High-level error codes
+    //
+    uint8_t got_hl = (ret & 0xFF80) != 0;
+    if (got_hl) {
+        use_ret = ret & 0xFF80;
+
+        // special case
+#if defined(MBEDTLS_SSL_TLS_C)
+        if (use_ret == -(MBEDTLS_ERR_SSL_FATAL_ALERT_MESSAGE)) {
+            strncpy(buf, "MBEDTLS_ERR_SSL_FATAL_ALERT_MESSAGE", buflen);
+            buf[buflen-1] = 0;
+            return;
+        }
+#endif
+
+        size_t len = mbedtls_err_to_str(use_ret, mbedtls_high_level_error_tab,
+                ARRAY_SIZE(mbedtls_high_level_error_tab), buf, buflen);
+
+        buf += len;
+        buflen -= len;
+        if (buflen == 0) return;
+    }
+
+    //
+    // Low-level error codes
+    //
+    use_ret = ret & ~0xFF80;
+
+    if (use_ret == 0) return;
+
+    // If high level code is present, make a concatenation between both error strings.
+    if (got_hl) {
+        if (buflen < 2) return;
+        *buf++ = '+';
+        buflen--;
+    }
+
+    mbedtls_err_to_str(use_ret, mbedtls_low_level_error_tab,
+            ARRAY_SIZE(mbedtls_low_level_error_tab), buf, buflen);
+}
+
+#else /* MBEDTLS_ERROR_C */
+
+#if defined(MBEDTLS_ERROR_STRERROR_DUMMY)
+
+/*
+ * Provide an non-function in case MBEDTLS_ERROR_C is not defined
+ */
+void mbedtls_strerror( int ret, char *buf, size_t buflen )
+{
+    ((void) ret);
+
+    if( buflen > 0 )
+        buf[0] = '\0';
+}
+
+#endif /* MBEDTLS_ERROR_STRERROR_DUMMY */
+
+#endif /* MBEDTLS_ERROR_C */

lib/mbedtls_errors/tester.c

@@ -0,0 +1,58 @@
+#include "mbedtls/error.h"
+#include <string.h>
+#include <stdio.h>
+
+// test_code checks that the provided code results in the provided error string for any size
+// buffer. It calls mbedtls_strerror() to fill a buffer that is from 1 to 100 bytes in length
+// and then checks that the buffer contents is OK and that a few guard bytes before and after
+// the buffer were not overwritten.
+int test_code(int code, char *str) {
+    char buf[100];
+    int ok = 1;
+    int res;
+
+    // test zero-length buffer
+    memset(buf, -3, 100);
+    mbedtls_strerror(code, buf + 4, 0);
+    for (int i = 0; i < 10; i++) {
+        if (buf[i] != -3) {
+            printf("Error: guard overwritten buflen=0 i=%d buf[i]=%d\n", i, buf[i]);
+            ok = 0;
+        }
+    }
+
+    // test
+    for (size_t buflen = 1; buflen < 90; buflen++) {
+        memset(buf, -3, 100);
+        mbedtls_strerror(code, buf + 4, buflen);
+        for (int i = 0; i < 4; i++) {
+            if (buf[i] != -3) {
+                printf("Error: pre-guard overwritten buflen=%d i=%d buf[i]=%d\n", buflen, i, buf[i]);
+                ok = 0;
+            }
+        }
+        for (int i = 4 + buflen; i < 100; i++) {
+            if (buf[i] != -3) {
+                printf("Error: post-guard overwritten buflen=%d i=%d buf[i]=%d\n", buflen, i, buf[i]);
+                ok = 0;
+            }
+        }
+        char exp[100];
+        strncpy(exp, str, buflen);
+        exp[buflen - 1] = 0;
+        if (strcmp(buf + 4, exp) != 0) {
+            printf("Error: expected %s, got %s\n", exp, buf);
+            ok = 0;
+        }
+    }
+
+    printf("Test %x -> %s is %s\n", code, str, ok?"OK":"*** BAD ***");
+}
+
+int main() {
+    test_code(0x7200, "MBEDTLS_ERR_SSL_INVALID_RECORD");
+    test_code(0x7780, "MBEDTLS_ERR_SSL_FATAL_ALERT_MESSAGE");
+    test_code(0x0074, "MBEDTLS_ERR_SHA256_BAD_INPUT_DATA");
+    test_code(0x6600 | 0x0074, "MBEDTLS_ERR_SSL_INVALID_VERIFY_HASH+MBEDTLS_ERR_SHA256_BAD_INPUT_DATA");
+    test_code(103, "MBEDTLS_ERR_UNKNOWN (0x0067)");
+}

tools/codeformat.py

@@ -38,6 +38,7 @@ PATHS = [
     "extmod/*.[ch]",
     "extmod/btstack/*.[ch]",
     "extmod/nimble/*.[ch]",
+    "lib/mbedtls_errors/tester.c",
     "lib/netutils/*.[ch]",
     "lib/timeutils/*.[ch]",
     "lib/utils/*.[ch]",