Squashed commit upgrading to mbedtls-2.28.1

Squash merging branch import/mbedtls-2.28.1

 ebf1f6a58089 ("libmbedtls: compile new files added with 2.28.1")
 3ffb51b58a54 ("libmbedtls: add SM2 curve")
 c425755720b4 ("libmbedtls: mbedtls_mpi_exp_mod(): optimize mempool usage")
 23493c822a82 ("libmbedtls: mbedtls_mpi_exp_mod(): reduce stack usage")
 dcdca2348dff ("libmbedtls: mbedtls_mpi_exp_mod() initialize W")
 dc2994976958 ("libmbedtls: fix no CRT issue")
 c6628873b281 ("libmbedtls: add interfaces in mbedtls for context memory operation")
 8acd202d3e55 ("libmedtls: mpi_miller_rabin: increase count limit")
 37284e28d5d9 ("libmbedtls: add mbedtls_mpi_init_mempool()")
 b499a75f29f3 ("libmbedtls: make mbedtls_mpi_mont*() available")
 2080a8c96a5d ("mbedtls: configure mbedtls to reach for config")
 e0858334327a ("mbedtls: remove default include/mbedtls/config.h")
 dd9688e6b8ce ("Import mbedtls-2.28.1")

Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>
Acked-by: Jens Wiklander <jens.wiklander@linaro.org>
diff --git a/lib/libmbedtls/mbedtls/library/ssl_cli.c b/lib/libmbedtls/mbedtls/library/ssl_cli.c
index f49178c..72351c9 100644
--- a/lib/libmbedtls/mbedtls/library/ssl_cli.c
+++ b/lib/libmbedtls/mbedtls/library/ssl_cli.c
@@ -33,9 +33,11 @@
 #include "mbedtls/ssl_internal.h"
 #include "mbedtls/debug.h"
 #include "mbedtls/error.h"
+#include "mbedtls/constant_time.h"
 
 #if defined(MBEDTLS_USE_PSA_CRYPTO)
 #include "mbedtls/psa_util.h"
+#include "psa/crypto.h"
 #endif /* MBEDTLS_USE_PSA_CRYPTO */
 
 #include <string.h>
@@ -51,6 +53,7 @@
 #endif
 
 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_conf_has_static_psk( mbedtls_ssl_config const *conf )
 {
     if( conf->psk_identity     == NULL ||
@@ -71,6 +74,7 @@
 }
 
 #if defined(MBEDTLS_USE_PSA_CRYPTO)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_conf_has_static_raw_psk( mbedtls_ssl_config const *conf )
 {
     if( conf->psk_identity     == NULL ||
@@ -89,6 +93,7 @@
 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED */
 
 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_write_hostname_ext( mbedtls_ssl_context *ssl,
                                    unsigned char *buf,
                                    const unsigned char *end,
@@ -136,18 +141,19 @@
      * } ServerNameList;
      *
      */
-    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SERVERNAME >> 8 ) & 0xFF );
-    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SERVERNAME      ) & 0xFF );
+    MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_SERVERNAME, p, 0 );
+    p += 2;
 
-    *p++ = (unsigned char)( ( (hostname_len + 5) >> 8 ) & 0xFF );
-    *p++ = (unsigned char)( ( (hostname_len + 5)      ) & 0xFF );
+    MBEDTLS_PUT_UINT16_BE( hostname_len + 5, p, 0 );
+    p += 2;
 
-    *p++ = (unsigned char)( ( (hostname_len + 3) >> 8 ) & 0xFF );
-    *p++ = (unsigned char)( ( (hostname_len + 3)      ) & 0xFF );
+    MBEDTLS_PUT_UINT16_BE( hostname_len + 3, p, 0 );
+    p += 2;
 
-    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SERVERNAME_HOSTNAME ) & 0xFF );
-    *p++ = (unsigned char)( ( hostname_len >> 8 ) & 0xFF );
-    *p++ = (unsigned char)( ( hostname_len      ) & 0xFF );
+    *p++ = MBEDTLS_BYTE_0( MBEDTLS_TLS_EXT_SERVERNAME_HOSTNAME );
+
+    MBEDTLS_PUT_UINT16_BE( hostname_len, p, 0 );
+    p += 2;
 
     memcpy( p, ssl->hostname, hostname_len );
 
@@ -158,6 +164,7 @@
 #endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
 
 #if defined(MBEDTLS_SSL_RENEGOTIATION)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_write_renegotiation_ext( mbedtls_ssl_context *ssl,
                                         unsigned char *buf,
                                         const unsigned char *end,
@@ -181,14 +188,12 @@
     /*
      * Secure renegotiation
      */
-    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_RENEGOTIATION_INFO >> 8 )
-                            & 0xFF );
-    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_RENEGOTIATION_INFO      )
-                            & 0xFF );
+    MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_RENEGOTIATION_INFO, p, 0 );
+    p += 2;
 
     *p++ = 0x00;
-    *p++ = ( ssl->verify_data_len + 1 ) & 0xFF;
-    *p++ = ssl->verify_data_len & 0xFF;
+    *p++ = MBEDTLS_BYTE_0( ssl->verify_data_len + 1 );
+    *p++ = MBEDTLS_BYTE_0( ssl->verify_data_len );
 
     memcpy( p, ssl->own_verify_data, ssl->verify_data_len );
 
@@ -203,6 +208,7 @@
  */
 #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
     defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_write_signature_algorithms_ext( mbedtls_ssl_context *ssl,
                                                unsigned char *buf,
                                                const unsigned char *end,
@@ -283,14 +289,14 @@
      * SignatureAndHashAlgorithm
      *   supported_signature_algorithms<2..2^16-2>;
      */
-    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SIG_ALG >> 8 ) & 0xFF );
-    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SIG_ALG      ) & 0xFF );
+    MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_SIG_ALG, p, 0 );
+    p += 2;
 
-    *p++ = (unsigned char)( ( ( sig_alg_len + 2 ) >> 8 ) & 0xFF );
-    *p++ = (unsigned char)( ( ( sig_alg_len + 2 )      ) & 0xFF );
+    MBEDTLS_PUT_UINT16_BE( sig_alg_len + 2, p, 0 );
+    p += 2;
 
-    *p++ = (unsigned char)( ( sig_alg_len >> 8 ) & 0xFF );
-    *p++ = (unsigned char)( ( sig_alg_len      ) & 0xFF );
+    MBEDTLS_PUT_UINT16_BE( sig_alg_len, p, 0 );
+    p += 2;
 
     *olen = 6 + sig_alg_len;
 
@@ -301,6 +307,7 @@
 
 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
     defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_write_supported_elliptic_curves_ext( mbedtls_ssl_context *ssl,
                                                     unsigned char *buf,
                                                     const unsigned char *end,
@@ -354,26 +361,25 @@
          grp_id++ )
     {
         info = mbedtls_ecp_curve_info_from_grp_id( *grp_id );
-        elliptic_curve_list[elliptic_curve_len++] = info->tls_id >> 8;
-        elliptic_curve_list[elliptic_curve_len++] = info->tls_id & 0xFF;
+        elliptic_curve_list[elliptic_curve_len++] = MBEDTLS_BYTE_1( info->tls_id );
+        elliptic_curve_list[elliptic_curve_len++] = MBEDTLS_BYTE_0( info->tls_id );
     }
 
-    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SUPPORTED_ELLIPTIC_CURVES >> 8 )
-                            & 0xFF );
-    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SUPPORTED_ELLIPTIC_CURVES      )
-                            & 0xFF );
+    MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_SUPPORTED_ELLIPTIC_CURVES, p, 0 );
+    p += 2;
 
-    *p++ = (unsigned char)( ( ( elliptic_curve_len + 2 ) >> 8 ) & 0xFF );
-    *p++ = (unsigned char)( ( ( elliptic_curve_len + 2 )      ) & 0xFF );
+    MBEDTLS_PUT_UINT16_BE( elliptic_curve_len + 2, p, 0 );
+    p += 2;
 
-    *p++ = (unsigned char)( ( ( elliptic_curve_len     ) >> 8 ) & 0xFF );
-    *p++ = (unsigned char)( ( ( elliptic_curve_len     )      ) & 0xFF );
+    MBEDTLS_PUT_UINT16_BE( elliptic_curve_len, p, 0 );
+    p += 2;
 
     *olen = 6 + elliptic_curve_len;
 
     return( 0 );
 }
 
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_write_supported_point_formats_ext( mbedtls_ssl_context *ssl,
                                                   unsigned char *buf,
                                                   const unsigned char *end,
@@ -388,10 +394,8 @@
         ( "client hello, adding supported_point_formats extension" ) );
     MBEDTLS_SSL_CHK_BUF_PTR( p, end, 6 );
 
-    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS >> 8 )
-                            & 0xFF );
-    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS      )
-                            & 0xFF );
+    MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS, p, 0 );
+    p += 2;
 
     *p++ = 0x00;
     *p++ = 2;
@@ -407,6 +411,7 @@
           MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
 
 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_write_ecjpake_kkpp_ext( mbedtls_ssl_context *ssl,
                                        unsigned char *buf,
                                        const unsigned char *end,
@@ -427,8 +432,8 @@
 
     MBEDTLS_SSL_CHK_BUF_PTR( p, end, 4 );
 
-    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_ECJPAKE_KKPP >> 8 ) & 0xFF );
-    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_ECJPAKE_KKPP      ) & 0xFF );
+    MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_ECJPAKE_KKPP, p, 0 );
+    p += 2;
 
     /*
      * We may need to send ClientHello multiple times for Hello verification.
@@ -470,8 +475,8 @@
         memcpy( p + 2, ssl->handshake->ecjpake_cache, kkpp_len );
     }
 
-    *p++ = (unsigned char)( ( kkpp_len >> 8 ) & 0xFF );
-    *p++ = (unsigned char)( ( kkpp_len      ) & 0xFF );
+    MBEDTLS_PUT_UINT16_BE( kkpp_len, p, 0 );
+    p += 2;
 
     *olen = kkpp_len + 4;
 
@@ -480,6 +485,7 @@
 #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
 
 #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_write_cid_ext( mbedtls_ssl_context *ssl,
                               unsigned char *buf,
                               const unsigned char *end,
@@ -510,11 +516,11 @@
     MBEDTLS_SSL_CHK_BUF_PTR( p, end, (unsigned)( ssl->own_cid_len + 5 ) );
 
     /* Add extension ID + size */
-    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_CID >> 8 ) & 0xFF );
-    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_CID      ) & 0xFF );
+    MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_CID, p, 0 );
+    p += 2;
     ext_len = (size_t) ssl->own_cid_len + 1;
-    *p++ = (unsigned char)( ( ext_len >> 8 ) & 0xFF );
-    *p++ = (unsigned char)( ( ext_len      ) & 0xFF );
+    MBEDTLS_PUT_UINT16_BE( ext_len, p, 0 );
+    p += 2;
 
     *p++ = (uint8_t) ssl->own_cid_len;
     memcpy( p, ssl->own_cid, ssl->own_cid_len );
@@ -526,6 +532,7 @@
 #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
 
 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_write_max_fragment_length_ext( mbedtls_ssl_context *ssl,
                                               unsigned char *buf,
                                               const unsigned char *end,
@@ -543,10 +550,8 @@
 
     MBEDTLS_SSL_CHK_BUF_PTR( p, end, 5 );
 
-    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH >> 8 )
-                            & 0xFF );
-    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH      )
-                            & 0xFF );
+    MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH, p, 0 );
+    p += 2;
 
     *p++ = 0x00;
     *p++ = 1;
@@ -560,6 +565,7 @@
 #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
 
 #if defined(MBEDTLS_SSL_TRUNCATED_HMAC)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_write_truncated_hmac_ext( mbedtls_ssl_context *ssl,
                                          unsigned char *buf,
                                          const unsigned char *end,
@@ -577,8 +583,8 @@
 
     MBEDTLS_SSL_CHK_BUF_PTR( p, end, 4 );
 
-    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_TRUNCATED_HMAC >> 8 ) & 0xFF );
-    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_TRUNCATED_HMAC      ) & 0xFF );
+    MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_TRUNCATED_HMAC, p, 0 );
+    p += 2;
 
     *p++ = 0x00;
     *p++ = 0x00;
@@ -590,6 +596,7 @@
 #endif /* MBEDTLS_SSL_TRUNCATED_HMAC */
 
 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_write_encrypt_then_mac_ext( mbedtls_ssl_context *ssl,
                                            unsigned char *buf,
                                            const unsigned char *end,
@@ -608,8 +615,8 @@
 
     MBEDTLS_SSL_CHK_BUF_PTR( p, end, 4 );
 
-    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC >> 8 ) & 0xFF );
-    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC      ) & 0xFF );
+    MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC, p, 0 );
+    p += 2;
 
     *p++ = 0x00;
     *p++ = 0x00;
@@ -621,6 +628,7 @@
 #endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */
 
 #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_write_extended_ms_ext( mbedtls_ssl_context *ssl,
                                       unsigned char *buf,
                                       const unsigned char *end,
@@ -639,10 +647,8 @@
 
     MBEDTLS_SSL_CHK_BUF_PTR( p, end, 4 );
 
-    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_EXTENDED_MASTER_SECRET >> 8 )
-                            & 0xFF );
-    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_EXTENDED_MASTER_SECRET      )
-                            & 0xFF );
+    MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_EXTENDED_MASTER_SECRET, p, 0 );
+    p += 2;
 
     *p++ = 0x00;
     *p++ = 0x00;
@@ -654,6 +660,7 @@
 #endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */
 
 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_write_session_ticket_ext( mbedtls_ssl_context *ssl,
                                          unsigned char *buf,
                                          const unsigned char *end,
@@ -673,11 +680,11 @@
     /* The addition is safe here since the ticket length is 16 bit. */
     MBEDTLS_SSL_CHK_BUF_PTR( p, end, 4 + tlen );
 
-    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SESSION_TICKET >> 8 ) & 0xFF );
-    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SESSION_TICKET      ) & 0xFF );
+    MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_SESSION_TICKET, p, 0 );
+    p += 2;
 
-    *p++ = (unsigned char)( ( tlen >> 8 ) & 0xFF );
-    *p++ = (unsigned char)( ( tlen      ) & 0xFF );
+    MBEDTLS_PUT_UINT16_BE( tlen, p, 0 );
+    p += 2;
 
     *olen = 4;
 
@@ -696,6 +703,7 @@
 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
 
 #if defined(MBEDTLS_SSL_ALPN)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_write_alpn_ext( mbedtls_ssl_context *ssl,
                                unsigned char *buf,
                                const unsigned char *end,
@@ -717,8 +725,8 @@
 
     MBEDTLS_SSL_CHK_BUF_PTR( p, end, 6 + alpnlen );
 
-    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_ALPN >> 8 ) & 0xFF );
-    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_ALPN      ) & 0xFF );
+    MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_ALPN, p, 0 );
+    p += 2;
 
     /*
      * opaque ProtocolName<1..2^8-1>;
@@ -745,18 +753,17 @@
     *olen = p - buf;
 
     /* List length = olen - 2 (ext_type) - 2 (ext_len) - 2 (list_len) */
-    buf[4] = (unsigned char)( ( ( *olen - 6 ) >> 8 ) & 0xFF );
-    buf[5] = (unsigned char)( ( ( *olen - 6 )      ) & 0xFF );
+    MBEDTLS_PUT_UINT16_BE( *olen - 6, buf, 4 );
 
     /* Extension length = olen - 2 (ext_type) - 2 (ext_len) */
-    buf[2] = (unsigned char)( ( ( *olen - 4 ) >> 8 ) & 0xFF );
-    buf[3] = (unsigned char)( ( ( *olen - 4 )      ) & 0xFF );
+    MBEDTLS_PUT_UINT16_BE( *olen - 4, buf, 2 );
 
     return( 0 );
 }
 #endif /* MBEDTLS_SSL_ALPN */
 
 #if defined(MBEDTLS_SSL_DTLS_SRTP)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_write_use_srtp_ext( mbedtls_ssl_context *ssl,
                                    unsigned char *buf,
                                    const unsigned char *end,
@@ -802,12 +809,11 @@
      */
     MBEDTLS_SSL_CHK_BUF_PTR( p, end, ext_len + 4 );
 
-    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_USE_SRTP >> 8 ) & 0xFF );
-    *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_USE_SRTP      ) & 0xFF );
+    MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_USE_SRTP, p, 0 );
+    p += 2;
 
-
-    *p++ = (unsigned char)( ( ( ext_len & 0xFF00 ) >> 8 ) & 0xFF );
-    *p++ = (unsigned char)( ext_len & 0xFF );
+    MBEDTLS_PUT_UINT16_BE( ext_len, p, 0 );
+    p += 2;
 
     /* protection profile length: 2*(ssl->conf->dtls_srtp_profile_list_len) */
     /* micro-optimization:
@@ -818,8 +824,7 @@
      *                        >> 8 ) & 0xFF );
      */
     *p++ = 0;
-    *p++ = (unsigned char)( ( 2 * ssl->conf->dtls_srtp_profile_list_len )
-                            & 0xFF );
+    *p++ = MBEDTLS_BYTE_0( 2 * ssl->conf->dtls_srtp_profile_list_len );
 
     for( protection_profiles_index=0;
          protection_profiles_index < ssl->conf->dtls_srtp_profile_list_len;
@@ -831,8 +836,8 @@
         {
             MBEDTLS_SSL_DEBUG_MSG( 3, ( "ssl_write_use_srtp_ext, add profile: %04x",
                                         profile_value ) );
-            *p++ = ( ( profile_value >> 8 ) & 0xFF );
-            *p++ = ( profile_value & 0xFF );
+            MBEDTLS_PUT_UINT16_BE( profile_value, p, 0 );
+            p += 2;
         }
         else
         {
@@ -879,6 +884,7 @@
 /*
  * Generate random bytes for ClientHello
  */
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_generate_random( mbedtls_ssl_context *ssl )
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
@@ -900,10 +906,8 @@
 
 #if defined(MBEDTLS_HAVE_TIME)
     t = mbedtls_time( NULL );
-    *p++ = (unsigned char)( t >> 24 );
-    *p++ = (unsigned char)( t >> 16 );
-    *p++ = (unsigned char)( t >>  8 );
-    *p++ = (unsigned char)( t       );
+    MBEDTLS_PUT_UINT32_BE( t, p, 0 );
+    p += 4;
 
     MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, current time: %" MBEDTLS_PRINTF_LONGLONG,
                                 (long long) t ) );
@@ -930,6 +934,7 @@
  *
  * \return          0 if valid, else 1
  */
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_validate_ciphersuite(
     const mbedtls_ssl_ciphersuite_t * suite_info,
     const mbedtls_ssl_context * ssl,
@@ -973,6 +978,7 @@
     return( 0 );
 }
 
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_write_client_hello( mbedtls_ssl_context *ssl )
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
@@ -1193,8 +1199,8 @@
         MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 );
 
         n++;
-        *p++ = (unsigned char)( ciphersuites[i] >> 8 );
-        *p++ = (unsigned char)( ciphersuites[i]      );
+        MBEDTLS_PUT_UINT16_BE( ciphersuites[i], p, 0 );
+        p += 2;
     }
 
     MBEDTLS_SSL_DEBUG_MSG( 3,
@@ -1209,8 +1215,8 @@
     {
         MBEDTLS_SSL_DEBUG_MSG( 3, ( "adding EMPTY_RENEGOTIATION_INFO_SCSV" ) );
         MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 );
-        *p++ = (unsigned char)( MBEDTLS_SSL_EMPTY_RENEGOTIATION_INFO >> 8 );
-        *p++ = (unsigned char)( MBEDTLS_SSL_EMPTY_RENEGOTIATION_INFO      );
+        MBEDTLS_PUT_UINT16_BE( MBEDTLS_SSL_EMPTY_RENEGOTIATION_INFO, p, 0 );
+        p += 2;
         n++;
     }
 
@@ -1221,8 +1227,8 @@
         MBEDTLS_SSL_DEBUG_MSG( 3, ( "adding FALLBACK_SCSV" ) );
 
         MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 );
-        *p++ = (unsigned char)( MBEDTLS_SSL_FALLBACK_SCSV_VALUE >> 8 );
-        *p++ = (unsigned char)( MBEDTLS_SSL_FALLBACK_SCSV_VALUE      );
+        MBEDTLS_PUT_UINT16_BE( MBEDTLS_SSL_FALLBACK_SCSV_VALUE, p, 0 );
+        p += 2;
         n++;
     }
 #endif
@@ -1428,9 +1434,8 @@
     {
         /* No need to check for space here, because the extension
          * writing functions already took care of that. */
-        *p++ = (unsigned char)( ( ext_len >> 8 ) & 0xFF );
-        *p++ = (unsigned char)( ( ext_len      ) & 0xFF );
-        p += ext_len;
+        MBEDTLS_PUT_UINT16_BE( ext_len, p, 0 );
+        p += 2 + ext_len;
     }
 
     ssl->out_msglen  = p - buf;
@@ -1464,6 +1469,7 @@
     return( 0 );
 }
 
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_parse_renegotiation_info( mbedtls_ssl_context *ssl,
                                          const unsigned char *buf,
                                          size_t len )
@@ -1474,9 +1480,9 @@
         /* Check verify-data in constant-time. The length OTOH is no secret */
         if( len    != 1 + ssl->verify_data_len * 2 ||
             buf[0] !=     ssl->verify_data_len * 2 ||
-            mbedtls_ssl_safer_memcmp( buf + 1,
+            mbedtls_ct_memcmp( buf + 1,
                           ssl->own_verify_data, ssl->verify_data_len ) != 0 ||
-            mbedtls_ssl_safer_memcmp( buf + 1 + ssl->verify_data_len,
+            mbedtls_ct_memcmp( buf + 1 + ssl->verify_data_len,
                           ssl->peer_verify_data, ssl->verify_data_len ) != 0 )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-matching renegotiation info" ) );
@@ -1508,6 +1514,7 @@
 }
 
 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_parse_max_fragment_length_ext( mbedtls_ssl_context *ssl,
                                               const unsigned char *buf,
                                               size_t len )
@@ -1534,6 +1541,7 @@
 #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
 
 #if defined(MBEDTLS_SSL_TRUNCATED_HMAC)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_parse_truncated_hmac_ext( mbedtls_ssl_context *ssl,
                                          const unsigned char *buf,
                                          size_t len )
@@ -1559,6 +1567,7 @@
 #endif /* MBEDTLS_SSL_TRUNCATED_HMAC */
 
 #if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_parse_cid_ext( mbedtls_ssl_context *ssl,
                               const unsigned char *buf,
                               size_t len )
@@ -1615,6 +1624,7 @@
 #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
 
 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_parse_encrypt_then_mac_ext( mbedtls_ssl_context *ssl,
                                          const unsigned char *buf,
                                          size_t len )
@@ -1641,6 +1651,7 @@
 #endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */
 
 #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_parse_extended_ms_ext( mbedtls_ssl_context *ssl,
                                          const unsigned char *buf,
                                          size_t len )
@@ -1667,6 +1678,7 @@
 #endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */
 
 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_parse_session_ticket_ext( mbedtls_ssl_context *ssl,
                                          const unsigned char *buf,
                                          size_t len )
@@ -1693,6 +1705,7 @@
 
 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
     defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_parse_supported_point_formats_ext( mbedtls_ssl_context *ssl,
                                                   const unsigned char *buf,
                                                   size_t len )
@@ -1738,6 +1751,7 @@
           MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
 
 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_parse_ecjpake_kkpp( mbedtls_ssl_context *ssl,
                                    const unsigned char *buf,
                                    size_t len )
@@ -1772,6 +1786,7 @@
 #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
 
 #if defined(MBEDTLS_SSL_ALPN)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_parse_alpn_ext( mbedtls_ssl_context *ssl,
                                const unsigned char *buf, size_t len )
 {
@@ -1842,6 +1857,7 @@
 #endif /* MBEDTLS_SSL_ALPN */
 
 #if defined(MBEDTLS_SSL_DTLS_SRTP)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_parse_use_srtp_ext( mbedtls_ssl_context *ssl,
                                    const unsigned char *buf,
                                    size_t len )
@@ -1962,6 +1978,7 @@
  * Parse HelloVerifyRequest.  Only called after verifying the HS type.
  */
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_parse_hello_verify_request( mbedtls_ssl_context *ssl )
 {
     const unsigned char *p = ssl->in_msg + mbedtls_ssl_hs_hdr_len( ssl );
@@ -2045,6 +2062,7 @@
 }
 #endif /* MBEDTLS_SSL_PROTO_DTLS */
 
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_parse_server_hello( mbedtls_ssl_context *ssl )
 {
     int ret, i;
@@ -2290,16 +2308,6 @@
     else
     {
         ssl->state = MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC;
-
-        if( ( ret = mbedtls_ssl_derive_keys( ssl ) ) != 0 )
-        {
-            MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_derive_keys", ret );
-            mbedtls_ssl_send_alert_message(
-                ssl,
-                MBEDTLS_SSL_ALERT_LEVEL_FATAL,
-                MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR );
-            return( ret );
-        }
     }
 
     MBEDTLS_SSL_DEBUG_MSG( 3, ( "%s session has been resumed",
@@ -2552,6 +2560,24 @@
     }
 
     /*
+     * mbedtls_ssl_derive_keys() has to be called after the parsing of the
+     * extensions. It sets the transform data for the resumed session which in
+     * case of DTLS includes the server CID extracted from the CID extension.
+     */
+    if( ssl->handshake->resume )
+    {
+        if( ( ret = mbedtls_ssl_derive_keys( ssl ) ) != 0 )
+        {
+            MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_derive_keys", ret );
+            mbedtls_ssl_send_alert_message(
+                ssl,
+                MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR );
+            return( ret );
+        }
+    }
+
+    /*
      * Renegotiation security checks
      */
     if( ssl->secure_renegotiation == MBEDTLS_SSL_LEGACY_RENEGOTIATION &&
@@ -2605,6 +2631,7 @@
 
 #if defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED) ||                       \
     defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_parse_server_dh_params( mbedtls_ssl_context *ssl,
                                        unsigned char **p,
                                        unsigned char *end )
@@ -2651,6 +2678,7 @@
     defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED) ||                     \
     defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) ||                      \
     defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_check_server_ecdh_params( const mbedtls_ssl_context *ssl )
 {
     const mbedtls_ecp_curve_info *curve_info;
@@ -2692,6 +2720,7 @@
 #if defined(MBEDTLS_USE_PSA_CRYPTO) &&                           \
         ( defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) ||     \
           defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) )
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_parse_server_ecdh_params_psa( mbedtls_ssl_context *ssl,
                                              unsigned char **p,
                                              unsigned char *end )
@@ -2717,6 +2746,10 @@
     tls_id <<= 8;
     tls_id |= *(*p)++;
 
+    /* Check it's a curve we offered */
+    if( mbedtls_ssl_check_curve_tls_id( ssl, tls_id ) != 0 )
+        return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
+
     /* Convert EC group to PSA key type. */
     if( ( handshake->ecdh_psa_type =
           mbedtls_psa_parse_tls_ecc_group( tls_id, &ecdh_bits ) ) == 0 )
@@ -2754,6 +2787,7 @@
 #if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) ||                     \
     defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) ||                   \
     defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_parse_server_ecdh_params( mbedtls_ssl_context *ssl,
                                          unsigned char **p,
                                          unsigned char *end )
@@ -2793,6 +2827,7 @@
           MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED */
 
 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_parse_server_psk_hint( mbedtls_ssl_context *ssl,
                                       unsigned char **p,
                                       unsigned char *end )
@@ -2839,6 +2874,7 @@
 /*
  * Generate a pre-master secret and encrypt it with the server's RSA key
  */
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_write_encrypted_pms( mbedtls_ssl_context *ssl,
                                     size_t offset, size_t *olen,
                                     size_t pms_offset )
@@ -2908,8 +2944,7 @@
     defined(MBEDTLS_SSL_PROTO_TLS1_2)
     if( len_bytes == 2 )
     {
-        ssl->out_msg[offset+0] = (unsigned char)( *olen >> 8 );
-        ssl->out_msg[offset+1] = (unsigned char)( *olen      );
+        MBEDTLS_PUT_UINT16_BE( *olen, ssl->out_msg, offset );
         *olen += 2;
     }
 #endif
@@ -2927,6 +2962,7 @@
 #if defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED) ||                       \
     defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) ||                     \
     defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_parse_signature_algorithm( mbedtls_ssl_context *ssl,
                                           unsigned char **p,
                                           unsigned char *end,
@@ -2993,6 +3029,7 @@
 
 #if defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \
     defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_get_ecdh_params_from_cert( mbedtls_ssl_context *ssl )
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
@@ -3011,6 +3048,8 @@
     peer_pk = &ssl->session_negotiate->peer_cert->pk;
 #endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
 
+    /* This is a public key, so it can't be opaque, so can_do() is a good
+     * enough check to ensure pk_ec() is safe to use below. */
     if( ! mbedtls_pk_can_do( peer_pk, MBEDTLS_PK_ECKEY ) )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "server key not ECDH capable" ) );
@@ -3044,6 +3083,7 @@
 #endif /* MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) ||
           MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */
 
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_parse_server_key_exchange( mbedtls_ssl_context *ssl )
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
@@ -3162,7 +3202,7 @@
                 MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
             return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
         }
-    } /* FALLTROUGH */
+    } /* FALLTHROUGH */
 #endif /* MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED */
 
 #if defined(MBEDTLS_KEY_EXCHANGE_PSK_ENABLED) ||                       \
@@ -3258,7 +3298,11 @@
     if( mbedtls_ssl_ciphersuite_uses_server_signature( ciphersuite_info ) )
     {
         size_t sig_len, hashlen;
-        unsigned char hash[64];
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
+        unsigned char hash[PSA_HASH_MAX_SIZE];
+#else
+        unsigned char hash[MBEDTLS_MD_MAX_SIZE];
+#endif
         mbedtls_md_type_t md_alg = MBEDTLS_MD_NONE;
         mbedtls_pk_type_t pk_alg = MBEDTLS_PK_NONE;
         unsigned char *params = ssl->in_msg + mbedtls_ssl_hs_hdr_len( ssl );
@@ -3446,6 +3490,7 @@
 }
 
 #if ! defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_parse_certificate_request( mbedtls_ssl_context *ssl )
 {
     const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
@@ -3464,6 +3509,7 @@
     return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
 }
 #else /* MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_parse_certificate_request( mbedtls_ssl_context *ssl )
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
@@ -3635,6 +3681,7 @@
 }
 #endif /* MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
 
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_parse_server_hello_done( mbedtls_ssl_context *ssl )
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
@@ -3674,6 +3721,7 @@
     return( 0 );
 }
 
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_write_client_key_exchange( mbedtls_ssl_context *ssl )
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
@@ -3693,8 +3741,7 @@
          */
         content_len = ssl->handshake->dhm_ctx.len;
 
-        ssl->out_msg[4] = (unsigned char)( content_len >> 8 );
-        ssl->out_msg[5] = (unsigned char)( content_len      );
+        MBEDTLS_PUT_UINT16_BE( content_len, ssl->out_msg, 4 );
         header_len = 6;
 
         ret = mbedtls_dhm_make_public( &ssl->handshake->dhm_ctx,
@@ -3730,7 +3777,8 @@
     if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_RSA ||
         ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA )
     {
-        psa_status_t status;
+        psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+        psa_status_t destruction_status = PSA_ERROR_CORRUPTION_DETECTED;
         psa_key_attributes_t key_attributes;
 
         mbedtls_ssl_handshake_params *handshake = ssl->handshake;
@@ -3773,13 +3821,19 @@
                                         own_pubkey, sizeof( own_pubkey ),
                                         &own_pubkey_len );
         if( status != PSA_SUCCESS )
+        {
+            psa_destroy_key( handshake->ecdh_psa_privkey );
+            handshake->ecdh_psa_privkey = MBEDTLS_SVC_KEY_ID_INIT;
             return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );
+        }
 
         if( mbedtls_psa_tls_psa_ec_to_ecpoint( own_pubkey,
                                                own_pubkey_len,
                                                &own_pubkey_ecpoint,
                                                &own_pubkey_ecpoint_len ) != 0 )
         {
+            psa_destroy_key( handshake->ecdh_psa_privkey );
+            handshake->ecdh_psa_privkey = MBEDTLS_SVC_KEY_ID_INIT;
             return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );
         }
 
@@ -3799,13 +3853,12 @@
                                         ssl->handshake->premaster,
                                         sizeof( ssl->handshake->premaster ),
                                         &ssl->handshake->pmslen );
-        if( status != PSA_SUCCESS )
-            return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );
 
-        status = psa_destroy_key( handshake->ecdh_psa_privkey );
-        if( status != PSA_SUCCESS )
-            return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );
+        destruction_status = psa_destroy_key( handshake->ecdh_psa_privkey );
         handshake->ecdh_psa_privkey = MBEDTLS_SVC_KEY_ID_INIT;
+
+        if( status != PSA_SUCCESS || destruction_status != PSA_SUCCESS )
+            return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );
     }
     else
 #endif /* MBEDTLS_USE_PSA_CRYPTO &&
@@ -3909,8 +3962,8 @@
             return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
         }
 
-        ssl->out_msg[header_len++] = (unsigned char)( content_len >> 8 );
-        ssl->out_msg[header_len++] = (unsigned char)( content_len      );
+        ssl->out_msg[header_len++] = MBEDTLS_BYTE_1( content_len );
+        ssl->out_msg[header_len++] = MBEDTLS_BYTE_0( content_len );
 
         memcpy( ssl->out_msg + header_len,
                 ssl->conf->psk_identity,
@@ -3930,7 +3983,10 @@
 #if defined(MBEDTLS_USE_PSA_CRYPTO)
             /* Opaque PSKs are currently only supported for PSK-only suites. */
             if( ssl_conf_has_static_raw_psk( ssl->conf ) == 0 )
+            {
+                MBEDTLS_SSL_DEBUG_MSG( 1, ( "opaque PSK not supported with RSA-PSK" ) );
                 return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
+            }
 #endif /* MBEDTLS_USE_PSA_CRYPTO */
 
             if( ( ret = ssl_write_encrypted_pms( ssl, header_len,
@@ -3945,7 +4001,10 @@
 #if defined(MBEDTLS_USE_PSA_CRYPTO)
             /* Opaque PSKs are currently only supported for PSK-only suites. */
             if( ssl_conf_has_static_raw_psk( ssl->conf ) == 0 )
+            {
+                MBEDTLS_SSL_DEBUG_MSG( 1, ( "opaque PSK not supported with DHE-PSK" ) );
                 return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
+            }
 #endif /* MBEDTLS_USE_PSA_CRYPTO */
 
             /*
@@ -3961,8 +4020,8 @@
                 return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
             }
 
-            ssl->out_msg[header_len++] = (unsigned char)( content_len >> 8 );
-            ssl->out_msg[header_len++] = (unsigned char)( content_len      );
+            ssl->out_msg[header_len++] = MBEDTLS_BYTE_1( content_len );
+            ssl->out_msg[header_len++] = MBEDTLS_BYTE_0( content_len );
 
             ret = mbedtls_dhm_make_public( &ssl->handshake->dhm_ctx,
                     (int) mbedtls_mpi_size( &ssl->handshake->dhm_ctx.P ),
@@ -3982,7 +4041,10 @@
 #if defined(MBEDTLS_USE_PSA_CRYPTO)
             /* Opaque PSKs are currently only supported for PSK-only suites. */
             if( ssl_conf_has_static_raw_psk( ssl->conf ) == 0 )
+            {
+                MBEDTLS_SSL_DEBUG_MSG( 1, ( "opaque PSK not supported with ECDHE-PSK" ) );
                 return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
+            }
 #endif /* MBEDTLS_USE_PSA_CRYPTO */
 
             /*
@@ -4092,6 +4154,7 @@
 }
 
 #if !defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_write_certificate_verify( mbedtls_ssl_context *ssl )
 {
     const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
@@ -4117,6 +4180,7 @@
     return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
 }
 #else /* !MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_write_certificate_verify( mbedtls_ssl_context *ssl )
 {
     int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
@@ -4268,8 +4332,7 @@
         return( ret );
     }
 
-    ssl->out_msg[4 + offset] = (unsigned char)( n >> 8 );
-    ssl->out_msg[5 + offset] = (unsigned char)( n      );
+    MBEDTLS_PUT_UINT16_BE( n, ssl->out_msg, offset + 4 );
 
     ssl->out_msglen  = 6 + n + offset;
     ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
@@ -4290,6 +4353,7 @@
 #endif /* MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
 
 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
+MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_parse_new_session_ticket( mbedtls_ssl_context *ssl )
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;