Merge remote-tracking branch 'public/pr/2957' into baremetal
diff --git a/include/mbedtls/entropy.h b/include/mbedtls/entropy.h
index ca06dc3..52cb6a0 100644
--- a/include/mbedtls/entropy.h
+++ b/include/mbedtls/entropy.h
@@ -83,8 +83,8 @@
 #define MBEDTLS_ENTROPY_MAX_SEED_SIZE   1024    /**< Maximum size of seed we read from seed file */
 #define MBEDTLS_ENTROPY_SOURCE_MANUAL   MBEDTLS_ENTROPY_MAX_SOURCES
 
-#define MBEDTLS_ENTROPY_SOURCE_STRONG   1       /**< Entropy source is strong   */
-#define MBEDTLS_ENTROPY_SOURCE_WEAK     0       /**< Entropy source is weak     */
+#define MBEDTLS_ENTROPY_SOURCE_STRONG   0x7F    /**< Entropy source is strong   */
+#define MBEDTLS_ENTROPY_SOURCE_WEAK     0x0     /**< Entropy source is weak     */
 
 #ifdef __cplusplus
 extern "C" {
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 8008b51..e14f58f 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -125,8 +125,13 @@
 #define MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED             -0x6A80  /**< DTLS client must retry for hello verification */
 #define MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL                  -0x6A00  /**< A buffer is too small to receive or write a message */
 #define MBEDTLS_ERR_SSL_NO_USABLE_CIPHERSUITE             -0x6980  /**< None of the common ciphersuites is usable (eg, no suitable certificate, see debug messages). */
-#define MBEDTLS_ERR_SSL_WANT_READ                         -0x6900  /**< No data of requested type currently available on underlying transport. */
-#define MBEDTLS_ERR_SSL_WANT_WRITE                        -0x6880  /**< Connection requires a write call. */
+/*
+ * MBEDTLS_ERR_SSL_WANT_READ and MBEDTLS_ERR_SSL_WANT_WRITE are dismissable errors,
+ * therefore the hamming distance to other non-dismissable errors should be
+ * large to prevent bit-flipping a non-dismissable error to dismissable.
+ */
+#define MBEDTLS_ERR_SSL_WANT_READ                         -0xFF6900  /**< No data of requested type currently available on underlying transport. */
+#define MBEDTLS_ERR_SSL_WANT_WRITE                        -0xFF6880  /**< Connection requires a write call. */
 #define MBEDTLS_ERR_SSL_TIMEOUT                           -0x6800  /**< The operation timed out. */
 #define MBEDTLS_ERR_SSL_CLIENT_RECONNECT                  -0x6780  /**< The client initiated a reconnect from the same port. */
 #define MBEDTLS_ERR_SSL_UNEXPECTED_RECORD                 -0x6700  /**< Record header looks valid but is not expected. */
@@ -191,10 +196,10 @@
 #define MBEDTLS_SSL_COMPRESS_NULL               0
 #define MBEDTLS_SSL_COMPRESS_DEFLATE            1
 
-#define MBEDTLS_SSL_VERIFY_NONE                 0
-#define MBEDTLS_SSL_VERIFY_OPTIONAL             1
-#define MBEDTLS_SSL_VERIFY_REQUIRED             2
-#define MBEDTLS_SSL_VERIFY_UNSET                3 /* Used only for sni_authmode */
+#define MBEDTLS_SSL_VERIFY_NONE                 0x0
+#define MBEDTLS_SSL_VERIFY_OPTIONAL             0xf
+#define MBEDTLS_SSL_VERIFY_REQUIRED             0x33
+#define MBEDTLS_SSL_VERIFY_UNSET                0x3c /* Used only for sni_authmode */
 
 #define MBEDTLS_SSL_LEGACY_RENEGOTIATION        0
 #define MBEDTLS_SSL_SECURE_RENEGOTIATION        1
@@ -564,25 +569,26 @@
  */
 typedef enum
 {
-    MBEDTLS_SSL_HELLO_REQUEST,
-    MBEDTLS_SSL_CLIENT_HELLO,
-    MBEDTLS_SSL_SERVER_HELLO,
-    MBEDTLS_SSL_SERVER_CERTIFICATE,
-    MBEDTLS_SSL_SERVER_KEY_EXCHANGE,
-    MBEDTLS_SSL_CERTIFICATE_REQUEST,
-    MBEDTLS_SSL_SERVER_HELLO_DONE,
-    MBEDTLS_SSL_CLIENT_CERTIFICATE,
-    MBEDTLS_SSL_CLIENT_KEY_EXCHANGE,
-    MBEDTLS_SSL_CERTIFICATE_VERIFY,
-    MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC,
-    MBEDTLS_SSL_CLIENT_FINISHED,
-    MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC,
-    MBEDTLS_SSL_SERVER_FINISHED,
-    MBEDTLS_SSL_FLUSH_BUFFERS,
-    MBEDTLS_SSL_HANDSHAKE_WRAPUP,
-    MBEDTLS_SSL_HANDSHAKE_OVER,
-    MBEDTLS_SSL_SERVER_NEW_SESSION_TICKET,
-    MBEDTLS_SSL_SERVER_HELLO_VERIFY_REQUEST_SENT,
+    MBEDTLS_SSL_HELLO_REQUEST                       = 0x0,
+    MBEDTLS_SSL_CLIENT_HELLO                        = 0x0000FFFF,
+    MBEDTLS_SSL_SERVER_HELLO                        = 0x00FF00FF,
+    MBEDTLS_SSL_SERVER_CERTIFICATE                  = 0x00FFFF00,
+    MBEDTLS_SSL_SERVER_KEY_EXCHANGE                 = 0x0F0F0F0F,
+    MBEDTLS_SSL_CERTIFICATE_REQUEST                 = 0x0F0FF0F0,
+    MBEDTLS_SSL_SERVER_HELLO_DONE                   = 0x0FF00FF0,
+    MBEDTLS_SSL_CLIENT_CERTIFICATE                  = 0x0FF0F00F,
+    MBEDTLS_SSL_CLIENT_KEY_EXCHANGE                 = 0x33333333,
+    MBEDTLS_SSL_CERTIFICATE_VERIFY                  = 0x3333CCCC,
+    MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC           = 0x33CC33CC,
+    MBEDTLS_SSL_CLIENT_FINISHED                     = 0x33CCCC33,
+    MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC           = 0x3C3C3C3C,
+    MBEDTLS_SSL_SERVER_FINISHED                     = 0x3C3CC3C3,
+    MBEDTLS_SSL_FLUSH_BUFFERS                       = 0x3CC33CC3,
+    MBEDTLS_SSL_HANDSHAKE_WRAPUP                    = 0x3CC3C33C,
+    MBEDTLS_SSL_HANDSHAKE_OVER                      = 0x55555555,
+    MBEDTLS_SSL_SERVER_NEW_SESSION_TICKET           = 0x5555AAAA,
+    MBEDTLS_SSL_SERVER_HELLO_VERIFY_REQUEST_SENT    = 0x55AA55AA,
+    MBEDTLS_SSL_INVALID                             = 0x55AAAA55
 }
 mbedtls_ssl_states;
 
@@ -1196,7 +1202,7 @@
 #endif /* !MBEDTLS_SSL_CONF_ENDPOINT */
     unsigned int transport : 1;     /*!< stream (TLS) or datagram (DTLS)    */
 #if !defined(MBEDTLS_SSL_CONF_AUTHMODE)
-    unsigned int authmode : 2;      /*!< MBEDTLS_SSL_VERIFY_XXX             */
+    unsigned int authmode : 6;      /*!< MBEDTLS_SSL_VERIFY_XXX             */
 #endif /* !MBEDTLS_SSL_CONF_AUTHMODE */
 #if !defined(MBEDTLS_SSL_CONF_ALLOW_LEGACY_RENEGOTIATION)
     /* needed even with renego disabled for LEGACY_BREAK_HANDSHAKE          */
diff --git a/include/mbedtls/ssl_internal.h b/include/mbedtls/ssl_internal.h
index 4872f6f..19328d8 100644
--- a/include/mbedtls/ssl_internal.h
+++ b/include/mbedtls/ssl_internal.h
@@ -226,6 +226,9 @@
         : ( MBEDTLS_SSL_IN_CONTENT_LEN )                             \
         )
 
+#define MBEDTLS_SSL_FI_FLAG_UNSET       0x0
+#define MBEDTLS_SSL_FI_FLAG_SET         0x7F
+
 /*
  * Check that we obey the standard's message size bounds
  */
@@ -385,6 +388,10 @@
 #if !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
     uint8_t got_peer_pubkey;            /*!< Did we store the peer's public key from its certificate? */
 #endif /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+    volatile uint8_t peer_authenticated;         /*!< Is the peer authenticated? */
+    volatile uint8_t hello_random_set;           /*!< Has the hello random been set? */
+    volatile uint8_t key_derivation_done;        /*!< Has the key derivation been done? */
+    volatile uint8_t premaster_generated;        /*!< Has the PMS been generated? */
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
     unsigned char verify_cookie_len;    /*!<  Cli: cookie length
                                               Srv: flag for sending a cookie */
@@ -506,7 +513,7 @@
 #endif /* !MBEDTLS_SSL_CONF_SINGLE_CIPHERSUITE */
 
 #if !defined(MBEDTLS_SSL_NO_SESSION_RESUMPTION)
-    int resume;                         /*!<  session resume indicator*/
+    volatile int resume;                /*!<  session resume indicator*/
 #endif /* !MBEDTLS_SSL_NO_SESSION_RESUMPTION */
 
 #if defined(MBEDTLS_SSL_SRV_C) &&                        \
@@ -905,7 +912,7 @@
 
 int mbedtls_ssl_handshake_client_step( mbedtls_ssl_context *ssl );
 int mbedtls_ssl_handshake_server_step( mbedtls_ssl_context *ssl );
-void mbedtls_ssl_handshake_wrapup( mbedtls_ssl_context *ssl );
+int mbedtls_ssl_handshake_wrapup( mbedtls_ssl_context *ssl );
 
 int mbedtls_ssl_send_fatal_handshake_failure( mbedtls_ssl_context *ssl );
 
diff --git a/library/entropy.c b/library/entropy.c
index 75421cf..b4d1f29 100644
--- a/library/entropy.c
+++ b/library/entropy.c
@@ -43,9 +43,7 @@
 #include <stdio.h>
 #endif
 
-#if defined(MBEDTLS_ENTROPY_NV_SEED)
 #include "mbedtls/platform.h"
-#endif
 
 #if defined(MBEDTLS_SELF_TEST)
 #if defined(MBEDTLS_PLATFORM_C)
@@ -258,7 +256,9 @@
  */
 static int entropy_gather_internal( mbedtls_entropy_context *ctx )
 {
-    int ret, i, have_one_strong = 0;
+    int i;
+    volatile int ret = MBEDTLS_ERR_ENTROPY_NO_STRONG_SOURCE;
+    volatile int have_one_strong_fi = MBEDTLS_ENTROPY_SOURCE_WEAK;
     unsigned char buf[MBEDTLS_ENTROPY_MAX_GATHER];
     size_t olen;
 
@@ -270,8 +270,16 @@
      */
     for( i = 0; i < ctx->source_count; i++ )
     {
-        if( ctx->source[i].strong == MBEDTLS_ENTROPY_SOURCE_STRONG )
-            have_one_strong = 1;
+        volatile int strong_fi = ctx->source[i].strong;
+        if( strong_fi == MBEDTLS_ENTROPY_SOURCE_STRONG )
+        {
+            mbedtls_platform_enforce_volatile_reads();
+
+            if( strong_fi == MBEDTLS_ENTROPY_SOURCE_STRONG )
+                have_one_strong_fi = MBEDTLS_ENTROPY_SOURCE_STRONG;
+            else
+                return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
+        }
 
         olen = 0;
         if( ( ret = ctx->source[i].f_source( ctx->source[i].p_source,
@@ -292,13 +300,24 @@
         }
     }
 
-    if( have_one_strong == 0 )
-        ret = MBEDTLS_ERR_ENTROPY_NO_STRONG_SOURCE;
-
 cleanup:
     mbedtls_platform_zeroize( buf, sizeof( buf ) );
 
-    return( ret );
+    if( have_one_strong_fi == MBEDTLS_ENTROPY_SOURCE_STRONG )
+    {
+        mbedtls_platform_enforce_volatile_reads();
+        if( have_one_strong_fi == MBEDTLS_ENTROPY_SOURCE_STRONG )
+        {
+            return( ret );
+        }
+        else
+        {
+            return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
+        }
+
+    }
+
+    return( MBEDTLS_ERR_ENTROPY_NO_STRONG_SOURCE );
 }
 
 /*
diff --git a/library/pk.c b/library/pk.c
index dfdd4d1..27276a8 100644
--- a/library/pk.c
+++ b/library/pk.c
@@ -1515,6 +1515,7 @@
                const unsigned char *sig, size_t sig_len,
                mbedtls_pk_restart_ctx *rs_ctx )
 {
+    volatile int verify_ret = MBEDTLS_ERR_PK_HW_ACCEL_FAILED;
     PK_VALIDATE_RET( ctx != NULL );
     PK_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE && hash_len == 0 ) ||
                      hash != NULL );
@@ -1547,8 +1548,23 @@
     (void) rs_ctx;
 #endif /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */
 
-    return( pk_info_verify_func( MBEDTLS_PK_CTX_INFO( ctx ),
-                ctx->pk_ctx, md_alg, hash, hash_len, sig, sig_len ) );
+    verify_ret = pk_info_verify_func( MBEDTLS_PK_CTX_INFO( ctx ),
+                        ctx->pk_ctx, md_alg, hash, hash_len, sig, sig_len );
+
+    if( verify_ret == 0 )
+    {
+        mbedtls_platform_enforce_volatile_reads();
+        if( verify_ret == 0 )
+        {
+            return( verify_ret );
+        }
+        else
+        {
+            verify_ret = MBEDTLS_ERR_PK_HW_ACCEL_FAILED;
+        }
+    }
+
+    return( verify_ret );
 }
 
 /*
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index 7c03b41..479554d 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -687,7 +687,7 @@
 #if defined(MBEDTLS_HAVE_TIME)
     mbedtls_time_t t;
 #endif
-
+    ssl->handshake->hello_random_set = MBEDTLS_SSL_FI_FLAG_UNSET;
     /*
      * When responding to a verify request, MUST reuse random (RFC 6347 4.2.1)
      */
@@ -713,13 +713,19 @@
     p += 4;
 #endif /* MBEDTLS_HAVE_TIME */
 
-    if( ( ret = mbedtls_ssl_conf_get_frng( ssl->conf )
-          ( mbedtls_ssl_conf_get_prng( ssl->conf ), p, 28 ) ) != 0 )
+    ret = mbedtls_ssl_conf_get_frng( ssl->conf )
+            ( mbedtls_ssl_conf_get_prng( ssl->conf ), p, 28 );
+    if( ret == 0 )
     {
-        return( ret );
+        mbedtls_platform_enforce_volatile_reads();
+        if( ret == 0 )
+        {
+            ssl->handshake->hello_random_set = MBEDTLS_SSL_FI_FLAG_SET;
+            return( 0 );
+        }
     }
 
-    return( 0 );
+    return( ret );
 }
 
 /**
@@ -862,7 +868,7 @@
      * appropriate length. Otherwise make the length 0 (for now, see next code
      * block for behaviour with tickets).
      */
-    if( mbedtls_ssl_handshake_get_resume( ssl->handshake ) == 0 ||
+    if( mbedtls_ssl_handshake_get_resume( ssl->handshake ) == MBEDTLS_SSL_FI_FLAG_UNSET ||
         mbedtls_ssl_get_renego_status( ssl ) != MBEDTLS_SSL_INITIAL_HANDSHAKE ||
         ssl->session_negotiate->id_len < 16 ||
         ssl->session_negotiate->id_len > 32 )
@@ -1116,7 +1122,7 @@
     ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
     ssl->out_msg[0]  = MBEDTLS_SSL_HS_CLIENT_HELLO;
 
-    ssl->state++;
+    ssl->state = MBEDTLS_SSL_SERVER_HELLO;
 
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
     if( MBEDTLS_SSL_TRANSPORT_IS_DTLS( ssl->conf->transport ) )
@@ -1719,8 +1725,15 @@
     MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, current time: %lu",
         (unsigned long)mbedtls_platform_get_uint32_be( &buf[2] ) ) );
 
+    ssl->handshake->hello_random_set = MBEDTLS_SSL_FI_FLAG_UNSET;
+
     mbedtls_platform_memcpy( ssl->handshake->randbytes + 32, buf + 2, 32 );
 
+    if( mbedtls_platform_memcmp( ssl->handshake->randbytes + 32, buf + 2, 32 ) == 0 )
+    {
+        ssl->handshake->hello_random_set = MBEDTLS_SSL_FI_FLAG_SET;
+    }
+
     n = buf[34];
 
     MBEDTLS_SSL_DEBUG_BUF( 3,   "server hello, random bytes", buf + 2, 32 );
@@ -1819,11 +1832,11 @@
         ssl->session_negotiate->id_len != n ||
         mbedtls_platform_memcmp( ssl->session_negotiate->id, buf + 35, n ) != 0 )
     {
-        ssl->handshake->resume = 0;
+        ssl->handshake->resume = MBEDTLS_SSL_FI_FLAG_UNSET;
     }
 #endif /* !MBEDTLS_SSL_NO_SESSION_RESUMPTION */
 
-    if( mbedtls_ssl_handshake_get_resume( ssl->handshake ) == 1 )
+    if( mbedtls_ssl_handshake_get_resume( ssl->handshake ) == MBEDTLS_SSL_FI_FLAG_SET )
     {
         /* Resume a session */
         ssl->state = MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC;
@@ -1839,7 +1852,7 @@
     else
     {
         /* Start a new session */
-        ssl->state++;
+        ssl->state = MBEDTLS_SSL_SERVER_CERTIFICATE;
 #if defined(MBEDTLS_HAVE_TIME)
         ssl->session_negotiate->start = mbedtls_time( NULL );
 #endif
@@ -2329,7 +2342,7 @@
                                          unsigned char* out,
                                          unsigned add_length_tag )
 {
-    int ret;
+    volatile int ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR;
 
     /*
      * Generate (part of) the pre-master secret as
@@ -2351,14 +2364,21 @@
                                mbedtls_ssl_conf_get_max_minor_ver( ssl->conf ),
                                ssl->conf->transport, out );
 
-    if( ( ret = mbedtls_ssl_conf_get_frng( ssl->conf )
-          ( mbedtls_ssl_conf_get_prng( ssl->conf ), out + 2, 46 ) ) != 0 )
+    ret = mbedtls_ssl_conf_get_frng( ssl->conf )
+          ( mbedtls_ssl_conf_get_prng( ssl->conf ), out + 2, 46 );
+
+    if( ret == 0 )
     {
-        MBEDTLS_SSL_DEBUG_RET( 1, "f_rng", ret );
-        return( ret );
+        mbedtls_platform_enforce_volatile_reads();
+        if( ret == 0 )
+        {
+            ssl->handshake->premaster_generated = MBEDTLS_SSL_FI_FLAG_SET;
+            return( 0 );
+        }
     }
 
-    return( 0 );
+    MBEDTLS_SSL_DEBUG_RET( 1, "f_rng", ret );
+    return( ret );
 }
 
 /*
@@ -2370,7 +2390,7 @@
                                         unsigned char *out, size_t buflen,
                                         size_t *olen )
 {
-    int ret;
+    volatile int ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR;
     size_t len_bytes = mbedtls_ssl_get_minor_ver( ssl ) ==
         MBEDTLS_SSL_MINOR_VERSION_0 ? 0 : 2;
     mbedtls_pk_context *peer_pk = NULL;
@@ -2414,16 +2434,27 @@
         goto cleanup;
     }
 
-    if( ( ret = mbedtls_pk_encrypt( peer_pk,
+    ret = mbedtls_pk_encrypt( peer_pk,
                             ppms, 48, out + len_bytes,
                             olen, buflen - len_bytes,
                             mbedtls_ssl_conf_get_frng( ssl->conf ),
-                            mbedtls_ssl_conf_get_prng( ssl->conf ) ) ) != 0 )
+                            mbedtls_ssl_conf_get_prng( ssl->conf ) );
+
+    if( ret == 0 )
+    {
+        mbedtls_platform_enforce_volatile_reads();
+        if( ret == 0 )
+        {
+            ssl->handshake->premaster_generated = MBEDTLS_SSL_FI_FLAG_SET;
+        }
+    }
+    else
     {
         MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_rsa_pkcs1_encrypt", ret );
         goto cleanup;
     }
 
+
 #if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \
     defined(MBEDTLS_SSL_PROTO_TLS1_2)
     if( len_bytes == 2 )
@@ -2731,7 +2762,11 @@
                                           unsigned char *buf,
                                           size_t buflen )
 {
-    int ret;
+    /*
+     * Initialising to an error value would need a significant
+     * structural change to provide default flow assumes failure
+     */
+    volatile int ret = 0;
     unsigned char *p;
     unsigned char *end;
 
@@ -3031,39 +3066,51 @@
             rs_ctx = &ssl->handshake->ecrs_ctx.pk;
 #endif
 
-        if( ( ret = mbedtls_pk_verify_restartable( peer_pk,
-                        md_alg, hash, hashlen, p, sig_len, rs_ctx ) ) != 0 )
+        ret = mbedtls_pk_verify_restartable( peer_pk,
+                        md_alg, hash, hashlen, p, sig_len, rs_ctx );
+
+        if( ret == 0 )
         {
-#if defined(MBEDTLS_SSL__ECP_RESTARTABLE)
-            if( ret != MBEDTLS_ERR_ECP_IN_PROGRESS )
-#endif
+            mbedtls_platform_enforce_volatile_reads();
+
+            if( ret == 0 )
             {
-                mbedtls_ssl_pend_fatal_alert( ssl,
-                                     MBEDTLS_SSL_ALERT_MSG_DECRYPT_ERROR );
+#if !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+                /* We don't need the peer's public key anymore. Free it,
+                * so that more RAM is available for upcoming expensive
+                * operations like ECDHE. */
+                mbedtls_pk_free( peer_pk );
+#else
+                mbedtls_x509_crt_pk_release(
+                    ssl->session_negotiate->peer_cert );
+#endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+                return( ret );
             }
+            else
+            {
+                return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
+            }
+        }
+#if defined(MBEDTLS_SSL__ECP_RESTARTABLE)
+        if( ret != MBEDTLS_ERR_ECP_IN_PROGRESS )
+#endif
+        {
+            mbedtls_ssl_pend_fatal_alert( ssl,
+                MBEDTLS_SSL_ALERT_MSG_DECRYPT_ERROR );
+        }
             MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_pk_verify", ret );
 #if defined(MBEDTLS_SSL__ECP_RESTARTABLE)
-            if( ret == MBEDTLS_ERR_ECP_IN_PROGRESS )
-                ret = MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS;
+        if( ret == MBEDTLS_ERR_ECP_IN_PROGRESS )
+            ret = MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS;
 #endif
 #if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
             mbedtls_x509_crt_pk_release( ssl->session_negotiate->peer_cert );
 #endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
-            return( ret );
-        }
 
-#if !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
-        /* We don't need the peer's public key anymore. Free it,
-         * so that more RAM is available for upcoming expensive
-         * operations like ECDHE. */
-        mbedtls_pk_free( peer_pk );
-#else
-        mbedtls_x509_crt_pk_release( ssl->session_negotiate->peer_cert );
-#endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
     }
 #endif /* MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED */
 
-    return( 0 );
+    return( ret );
 }
 
 static int ssl_in_server_key_exchange_postprocess( mbedtls_ssl_context *ssl )
@@ -3143,7 +3190,7 @@
     if( ! mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) )
     {
         MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate request" ) );
-        ssl->state++;
+        ssl->state = MBEDTLS_SSL_SERVER_HELLO_DONE;
         return( 0 );
     }
 
@@ -3165,7 +3212,7 @@
     if( ! mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) )
     {
         MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate request" ) );
-        ssl->state++;
+        ssl->state = MBEDTLS_SSL_SERVER_HELLO_DONE;
         return( 0 );
     }
 
@@ -3183,7 +3230,7 @@
         return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE );
     }
 
-    ssl->state++;
+    ssl->state = MBEDTLS_SSL_SERVER_HELLO_DONE;
     ssl->client_auth = ( ssl->in_msg[0] == MBEDTLS_SSL_HS_CERTIFICATE_REQUEST );
 
     MBEDTLS_SSL_DEBUG_MSG( 3, ( "got %s certificate request",
@@ -3340,7 +3387,7 @@
         return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO_DONE );
     }
 
-    ssl->state++;
+    ssl->state = MBEDTLS_SSL_CLIENT_CERTIFICATE;
 
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
     if( MBEDTLS_SSL_TRANSPORT_IS_DTLS( ssl->conf->transport ) )
@@ -3827,7 +3874,7 @@
     if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) )
     {
         MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate verify" ) );
-        ssl->state++;
+        ssl->state = MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC;
         return( 0 );
     }
 
@@ -3866,14 +3913,14 @@
     if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) )
     {
         MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate verify" ) );
-        ssl->state++;
+        ssl->state = MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC;
         return( 0 );
     }
 
     if( ssl->client_auth == 0 || mbedtls_ssl_own_cert( ssl ) == NULL )
     {
         MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate verify" ) );
-        ssl->state++;
+        ssl->state = MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC;
         return( 0 );
     }
 
@@ -3997,7 +4044,7 @@
     ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
     ssl->out_msg[0]  = MBEDTLS_SSL_HS_CERTIFICATE_VERIFY;
 
-    ssl->state++;
+    ssl->state = MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC;
 
     if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
     {
@@ -4251,9 +4298,10 @@
            break;
 
        case MBEDTLS_SSL_HANDSHAKE_WRAPUP:
-           mbedtls_ssl_handshake_wrapup( ssl );
+           ret = mbedtls_ssl_handshake_wrapup( ssl );
            break;
 
+       case MBEDTLS_SSL_INVALID:
        default:
            MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid state %d", ssl->state ) );
            return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index 1ef8f94..92d1da0 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -627,7 +627,7 @@
 
     MBEDTLS_SSL_DEBUG_MSG( 3, ( "session successfully restored from ticket" ) );
 
-    ssl->handshake->resume = 1;
+    ssl->handshake->resume = MBEDTLS_SSL_FI_FLAG_SET;
 
     /* Don't send a new ticket after all, this one is OK */
     ssl->handshake->new_session_ticket = 0;
@@ -1223,8 +1223,14 @@
     mbedtls_platform_memcpy( ssl->session_negotiate->id, p, ssl->session_negotiate->id_len );
 
     p += sess_len;
+
+    ssl->handshake->hello_random_set = MBEDTLS_SSL_FI_FLAG_UNSET;
     memset( ssl->handshake->randbytes, 0, 64 );
     mbedtls_platform_memcpy( ssl->handshake->randbytes + 32 - chal_len, p, chal_len );
+    if( mbedtls_platform_memcmp( ssl->handshake->randbytes + 32 - chal_len, p, chal_len ) == 0 )
+    {
+        ssl->handshake->hello_random_set = MBEDTLS_SSL_FI_FLAG_SET;
+    }
 
     /*
      * Check for TLS_EMPTY_RENEGOTIATION_INFO_SCSV
@@ -1360,7 +1366,7 @@
     }
 
     ssl->in_left = 0;
-    ssl->state++;
+    ssl->state = MBEDTLS_SSL_SERVER_HELLO;
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse client hello v2" ) );
 
@@ -1717,10 +1723,14 @@
     /*
      * Save client random (inc. Unix time)
      */
+    ssl->handshake->hello_random_set = MBEDTLS_SSL_FI_FLAG_UNSET;
     MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, random bytes", buf + 2, 32 );
 
     mbedtls_platform_memcpy( ssl->handshake->randbytes, buf + 2, 32 );
-
+    if( mbedtls_platform_memcmp( ssl->handshake->randbytes, buf + 2, 32 ) == 0 )
+    {
+        ssl->handshake->hello_random_set = MBEDTLS_SSL_FI_FLAG_SET;
+    }
     /*
      * Check the session ID length and save session ID
      */
@@ -2298,7 +2308,7 @@
         mbedtls_ssl_get_ciphersuite_name(
             mbedtls_ssl_session_get_ciphersuite( ssl->session_negotiate ) ) ) );
 
-    ssl->state++;
+    ssl->state = MBEDTLS_SSL_SERVER_HELLO;
 
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
     if( MBEDTLS_SSL_TRANSPORT_IS_DTLS( ssl->conf->transport ) )
@@ -2814,8 +2824,12 @@
     }
 
     p += 28;
-
+    ssl->handshake->hello_random_set = MBEDTLS_SSL_FI_FLAG_UNSET;
     mbedtls_platform_memcpy( ssl->handshake->randbytes + 32, buf + 6, 32 );
+    if( mbedtls_platform_memcmp( ssl->handshake->randbytes + 32, buf + 6, 32 ) == 0 )
+    {
+        ssl->handshake->hello_random_set = MBEDTLS_SSL_FI_FLAG_SET;
+    }
 
     MBEDTLS_SSL_DEBUG_BUF( 3, "server hello, random bytes", buf + 6, 32 );
 
@@ -2825,19 +2839,19 @@
      * It may be already set to 1 by ssl_parse_session_ticket_ext().
      * If not, try looking up session ID in our cache.
      */
-    if( mbedtls_ssl_handshake_get_resume( ssl->handshake ) == 0 &&
+    if( mbedtls_ssl_handshake_get_resume( ssl->handshake ) == MBEDTLS_SSL_FI_FLAG_UNSET &&
         mbedtls_ssl_get_renego_status( ssl ) == MBEDTLS_SSL_INITIAL_HANDSHAKE &&
         ssl->session_negotiate->id_len != 0 &&
         ssl->conf->f_get_cache != NULL &&
         ssl->conf->f_get_cache( ssl->conf->p_cache, ssl->session_negotiate ) == 0 )
     {
         MBEDTLS_SSL_DEBUG_MSG( 3, ( "session successfully restored from cache" ) );
-        ssl->handshake->resume = 1;
+        ssl->handshake->resume = MBEDTLS_SSL_FI_FLAG_SET;
     }
 #endif /* !MBEDTLS_SSL_NO_SESSION_CACHE */
 
 #if !defined(MBEDTLS_SSL_NO_SESSION_RESUMPTION)
-    if( mbedtls_ssl_handshake_get_resume( ssl->handshake ) == 1 )
+    if( mbedtls_ssl_handshake_get_resume( ssl->handshake ) == MBEDTLS_SSL_FI_FLAG_SET )
     {
         /*
          * Resuming a session
@@ -2858,7 +2872,7 @@
          * New session, create a new session id,
          * unless we're about to issue a session ticket
          */
-        ssl->state++;
+        ssl->state = MBEDTLS_SSL_SERVER_CERTIFICATE;
 
 #if defined(MBEDTLS_HAVE_TIME)
         ssl->session_negotiate->start = mbedtls_time( NULL );
@@ -3008,7 +3022,7 @@
     if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) )
     {
         MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate request" ) );
-        ssl->state++;
+        ssl->state = MBEDTLS_SSL_SERVER_HELLO_DONE;
         return( 0 );
     }
 
@@ -3030,7 +3044,7 @@
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write certificate request" ) );
 
-    ssl->state++;
+    ssl->state = MBEDTLS_SSL_SERVER_HELLO_DONE;
 
 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
     if( ssl->handshake->sni_authmode != MBEDTLS_SSL_VERIFY_UNSET )
@@ -3693,7 +3707,7 @@
         /* Key exchanges not involving ephemeral keys don't use
          * ServerKeyExchange, so end here. */
         MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write server key exchange" ) );
-        ssl->state++;
+        ssl->state = MBEDTLS_SSL_CERTIFICATE_REQUEST;
         return( 0 );
     }
 #endif /* MBEDTLS_KEY_EXCHANGE__SOME_NON_PFS__ENABLED */
@@ -3751,7 +3765,7 @@
     ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
     ssl->out_msg[0]  = MBEDTLS_SSL_HS_SERVER_KEY_EXCHANGE;
 
-    ssl->state++;
+    ssl->state = MBEDTLS_SSL_CERTIFICATE_REQUEST;
 
     if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
     {
@@ -3773,7 +3787,7 @@
     ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
     ssl->out_msg[0]  = MBEDTLS_SSL_HS_SERVER_HELLO_DONE;
 
-    ssl->state++;
+    ssl->state = MBEDTLS_SSL_CLIENT_CERTIFICATE;
 
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
     if( MBEDTLS_SSL_TRANSPORT_IS_DTLS( ssl->conf->transport ) )
@@ -3964,6 +3978,7 @@
     unsigned char mask;
     size_t i, peer_pmslen;
     unsigned int diff;
+    volatile unsigned int pmscounter = 0;
 
     /* In case of a failure in decryption, the decryption may write less than
      * 2 bytes of output, but we always read the first two bytes. It doesn't
@@ -4042,7 +4057,19 @@
     /* Set pms to either the true or the fake PMS, without
      * data-dependent branches. */
     for( i = 0; i < ssl->handshake->pmslen; i++ )
+    {
         pms[i] = ( mask & fake_pms[i] ) | ( (~mask) & peer_pms[i] );
+        pmscounter++;
+    }
+
+    if( pmscounter == ssl->handshake->pmslen )
+    {
+        mbedtls_platform_enforce_volatile_reads();
+        if( pmscounter == ssl->handshake->pmslen )
+        {
+            ssl->handshake->premaster_generated = MBEDTLS_SSL_FI_FLAG_SET;
+        }
+    }
 
     return( 0 );
 }
@@ -4422,7 +4449,7 @@
     if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) )
     {
         MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
-        ssl->state++;
+        ssl->state = MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC;
         return( 0 );
     }
 
@@ -4432,7 +4459,7 @@
 #else /* !MBEDTLS_KEY_EXCHANGE__CERT_REQ_ALLOWED__ENABLED */
 static int ssl_parse_certificate_verify( mbedtls_ssl_context *ssl )
 {
-    int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
+    volatile int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
     size_t i, sig_len;
     unsigned char hash[48];
     unsigned char *hash_start = hash;
@@ -4450,7 +4477,7 @@
     if( !mbedtls_ssl_ciphersuite_cert_req_allowed( ciphersuite_info ) )
     {
         MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
-        ssl->state++;
+        ssl->state = MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC;
         return( 0 );
     }
 
@@ -4478,7 +4505,7 @@
     if( peer_pk == NULL )
     {
         MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
-        ssl->state++;
+        ssl->state = MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC;
         return( 0 );
     }
 
@@ -4490,7 +4517,7 @@
         goto exit;
     }
 
-    ssl->state++;
+    ssl->state = MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC;
 
     /* Process the message contents */
     if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE ||
@@ -4618,17 +4645,25 @@
             md_alg, ssl, hash, &dummy_hlen );
     }
 
-    if( ( ret = mbedtls_pk_verify( peer_pk,
-                           md_alg, hash_start, hashlen,
-                           ssl->in_msg + i, sig_len ) ) != 0 )
+    ret = mbedtls_pk_verify( peer_pk,
+                                      md_alg, hash_start, hashlen,
+                                      ssl->in_msg + i, sig_len );
+
+    if( ret == 0 )
     {
-        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_pk_verify", ret );
-        goto exit;
+        mbedtls_platform_enforce_volatile_reads();
+
+        if( ret == 0 )
+        {
+            mbedtls_ssl_update_handshake_status( ssl );
+
+            MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse certificate verify" ) );
+            goto exit;
+        }
+
     }
 
-    mbedtls_ssl_update_handshake_status( ssl );
-
-    MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse certificate verify" ) );
+    MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_pk_verify", ret );
 
 exit:
 
@@ -4815,9 +4850,10 @@
             break;
 
         case MBEDTLS_SSL_HANDSHAKE_WRAPUP:
-            mbedtls_ssl_handshake_wrapup( ssl );
+            ret = mbedtls_ssl_handshake_wrapup( ssl );
             break;
 
+        case MBEDTLS_SSL_INVALID:
         default:
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid state %d", ssl->state ) );
             return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index c12af96..19bdc90 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -48,6 +48,8 @@
 #include "mbedtls/ssl_internal.h"
 #include "mbedtls/platform_util.h"
 #include "mbedtls/version.h"
+#include "mbedtls/platform.h"
+
 
 #include <string.h>
 
@@ -1825,7 +1827,7 @@
         mbedtls_ssl_handshake_get_ciphersuite( handshake );
 
 #if !defined(MBEDTLS_SSL_NO_SESSION_RESUMPTION)
-    if( handshake->resume != 0 )
+    if( handshake->resume == MBEDTLS_SSL_FI_FLAG_SET )
     {
         MBEDTLS_SSL_DEBUG_MSG( 3, ( "no premaster (session resumed)" ) );
         return( 0 );
@@ -1881,10 +1883,10 @@
 
 int mbedtls_ssl_derive_keys( mbedtls_ssl_context *ssl )
 {
-    int ret;
+    volatile int ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR;
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> derive keys" ) );
-
+    ssl->handshake->key_derivation_done = MBEDTLS_SSL_FI_FLAG_UNSET;
     /* Compute master secret if needed */
     ret = ssl_compute_master( ssl->handshake,
                               ssl->session_negotiate->master,
@@ -1925,7 +1927,19 @@
                   mbedtls_ssl_get_minor_ver( ssl ),
                   mbedtls_ssl_conf_get_endpoint( ssl->conf ),
                   ssl );
-    if( ret != 0 )
+    if( ret == 0 )
+    {
+        mbedtls_platform_enforce_volatile_reads();
+        if( ret == 0 )
+        {
+            ssl->handshake->key_derivation_done = MBEDTLS_SSL_FI_FLAG_SET;
+        }
+        else
+        {
+            return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
+        }
+    }
+    else
     {
         MBEDTLS_SSL_DEBUG_RET( 1, "ssl_populate_transform", ret );
         return( ret );
@@ -1958,11 +1972,10 @@
 
 int mbedtls_ssl_build_pms( mbedtls_ssl_context *ssl )
 {
-    int ret;
+    volatile int ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR;
 
     mbedtls_ssl_ciphersuite_handle_t ciphersuite_info =
         mbedtls_ssl_handshake_get_ciphersuite( ssl->handshake );
-
 #if defined(MBEDTLS_USE_TINYCRYPT)
     if( mbedtls_ssl_suite_get_key_exchange( ciphersuite_info )
         == MBEDTLS_KEY_EXCHANGE_ECDHE_RSA                       ||
@@ -1980,6 +1993,7 @@
             return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
         if( ret != UECC_SUCCESS )
             return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );
+        ssl->handshake->premaster_generated = MBEDTLS_SSL_FI_FLAG_SET;
 
         ssl->handshake->pmslen = NUM_ECC_BYTES;
     }
@@ -1989,12 +2003,26 @@
     if( mbedtls_ssl_suite_get_key_exchange( ciphersuite_info )
         == MBEDTLS_KEY_EXCHANGE_DHE_RSA )
     {
-        if( ( ret = mbedtls_dhm_calc_secret( &ssl->handshake->dhm_ctx,
+        ret = mbedtls_dhm_calc_secret( &ssl->handshake->dhm_ctx,
                                       ssl->handshake->premaster,
                                       MBEDTLS_PREMASTER_SIZE,
                                      &ssl->handshake->pmslen,
                                       mbedtls_ssl_conf_get_frng( ssl->conf ),
-                                      mbedtls_ssl_conf_get_prng( ssl->conf ) ) ) != 0 )
+                                      mbedtls_ssl_conf_get_prng( ssl->conf ) );
+        if( ret == 0 )
+        {
+            mbedtls_platform_enforce_volatile_reads();
+            if( ret == 0 )
+            {
+                ssl->handshake->premaster_generated = MBEDTLS_SSL_FI_FLAG_SET;
+            }
+            else
+            {
+                MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_calc_secret", ret );
+                return( ret );
+            }
+        }
+        else
         {
             MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_calc_secret", ret );
             return( ret );
@@ -2018,12 +2046,26 @@
         mbedtls_ssl_suite_get_key_exchange( ciphersuite_info )
         == MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA )
     {
-        if( ( ret = mbedtls_ecdh_calc_secret( &ssl->handshake->ecdh_ctx,
+        ret = mbedtls_ecdh_calc_secret( &ssl->handshake->ecdh_ctx,
                                       &ssl->handshake->pmslen,
                                        ssl->handshake->premaster,
                                        MBEDTLS_MPI_MAX_SIZE,
                                        mbedtls_ssl_conf_get_frng( ssl->conf ),
-                                       mbedtls_ssl_conf_get_prng( ssl->conf ) ) ) != 0 )
+                                       mbedtls_ssl_conf_get_prng( ssl->conf ) );
+        if( ret == 0 )
+        {
+            mbedtls_platform_enforce_volatile_reads();
+            if( ret == 0 )
+            {
+                ssl->handshake->premaster_generated = MBEDTLS_SSL_FI_FLAG_SET;
+            }
+            else
+            {
+                MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_calc_secret", ret );
+                return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
+            }
+        }
+        else
         {
             MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_calc_secret", ret );
             return( ret );
@@ -2039,8 +2081,22 @@
 #if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
     if( mbedtls_ssl_ciphersuite_uses_psk( ciphersuite_info ) )
     {
-        if( ( ret = mbedtls_ssl_psk_derive_premaster( ssl,
-            mbedtls_ssl_suite_get_key_exchange( ciphersuite_info ) ) ) != 0 )
+        ret = mbedtls_ssl_psk_derive_premaster( ssl,
+            mbedtls_ssl_suite_get_key_exchange( ciphersuite_info ) );
+        if( ret == 0 )
+        {
+            mbedtls_platform_enforce_volatile_reads();
+            if( ret == 0 )
+            {
+                ssl->handshake->premaster_generated = MBEDTLS_SSL_FI_FLAG_SET;
+            }
+            else
+            {
+                MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret );
+                return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
+            }
+        }
+        else
         {
             MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret );
             return( ret );
@@ -2056,7 +2112,20 @@
                 ssl->handshake->premaster, 32, &ssl->handshake->pmslen,
                 mbedtls_ssl_conf_get_frng( ssl->conf ),
                 mbedtls_ssl_conf_get_prng( ssl->conf ) );
-        if( ret != 0 )
+        if( ret == 0 )
+        {
+            mbedtls_platform_enforce_volatile_reads();
+            if( ret == 0 )
+            {
+                ssl->handshake->premaster_generated = MBEDTLS_SSL_FI_FLAG_SET;
+            }
+            else
+            {
+                MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_derive_secret", ret );
+                return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
+            }
+        }
+        else
         {
             MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_derive_secret", ret );
             return( ret );
@@ -2214,6 +2283,8 @@
 
     ssl->handshake->pmslen = p - ssl->handshake->premaster;
 
+    ssl->handshake->premaster_generated = MBEDTLS_SSL_FI_FLAG_SET;
+
     return( 0 );
 }
 #endif /* MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED */
@@ -4490,6 +4561,7 @@
     {
         unsigned i;
         size_t protected_record_size;
+        volatile int encrypted_fi = 0;
 
         /* Skip writing the record content type to after the encryption,
          * as it may change when using the CID extension. */
@@ -4544,6 +4616,13 @@
 #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
             ssl->out_msglen = len = rec.data_len;
             (void)mbedtls_platform_put_uint16_be( ssl->out_len, rec.data_len );
+            encrypted_fi = 1;
+        }
+
+        /* Double check to ensure the encryption has been done */
+        if( ssl->transform_out != NULL && encrypted_fi == 0 )
+        {
+            return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
         }
 
         protected_record_size = len + mbedtls_ssl_out_hdr_len( ssl );
@@ -6740,7 +6819,18 @@
     if( !mbedtls_ssl_ciphersuite_uses_srv_cert( ciphersuite_info ) )
     {
         MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate" ) );
-        ssl->state++;
+        if( ssl->state == MBEDTLS_SSL_CLIENT_CERTIFICATE )
+        {
+            ssl->state = MBEDTLS_SSL_CLIENT_KEY_EXCHANGE;
+        }
+        else if( ssl->state == MBEDTLS_SSL_SERVER_CERTIFICATE )
+        {
+            ssl->state = MBEDTLS_SSL_SERVER_KEY_EXCHANGE;
+        }
+        else
+        {
+            ssl->state = MBEDTLS_SSL_INVALID;
+        }
         return( 0 );
     }
 
@@ -6758,7 +6848,18 @@
     if( !mbedtls_ssl_ciphersuite_uses_srv_cert( ciphersuite_info ) )
     {
         MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate" ) );
-        ssl->state++;
+        if( ssl->state == MBEDTLS_SSL_CLIENT_CERTIFICATE )
+        {
+            ssl->state = MBEDTLS_SSL_CLIENT_KEY_EXCHANGE;
+        }
+        else if( ssl->state == MBEDTLS_SSL_SERVER_CERTIFICATE )
+        {
+            ssl->state = MBEDTLS_SSL_SERVER_KEY_EXCHANGE;
+        }
+        else
+        {
+            ssl->state = MBEDTLS_SSL_INVALID;
+        }
         return( 0 );
     }
 
@@ -6782,7 +6883,18 @@
     if( !mbedtls_ssl_ciphersuite_uses_srv_cert( ciphersuite_info ) )
     {
         MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate" ) );
-        ssl->state++;
+        if( ssl->state == MBEDTLS_SSL_CLIENT_CERTIFICATE )
+        {
+            ssl->state = MBEDTLS_SSL_CLIENT_KEY_EXCHANGE;
+        }
+        else if( ssl->state == MBEDTLS_SSL_SERVER_CERTIFICATE )
+        {
+            ssl->state = MBEDTLS_SSL_SERVER_KEY_EXCHANGE;
+        }
+        else
+        {
+            ssl->state = MBEDTLS_SSL_INVALID;
+        }
         return( 0 );
     }
 
@@ -6793,7 +6905,18 @@
         if( ssl->client_auth == 0 )
         {
             MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate" ) );
-            ssl->state++;
+            if( ssl->state == MBEDTLS_SSL_CLIENT_CERTIFICATE )
+            {
+                ssl->state = MBEDTLS_SSL_CLIENT_KEY_EXCHANGE;
+            }
+            else if( ssl->state == MBEDTLS_SSL_SERVER_CERTIFICATE )
+            {
+                ssl->state = MBEDTLS_SSL_SERVER_KEY_EXCHANGE;
+            }
+            else
+            {
+                ssl->state = MBEDTLS_SSL_INVALID;
+            }
             return( 0 );
         }
 
@@ -6867,7 +6990,18 @@
 write_msg:
 #endif
 
-    ssl->state++;
+    if( ssl->state == MBEDTLS_SSL_CLIENT_CERTIFICATE )
+    {
+        ssl->state = MBEDTLS_SSL_CLIENT_KEY_EXCHANGE;
+    }
+    else if( ssl->state == MBEDTLS_SSL_SERVER_CERTIFICATE )
+    {
+        ssl->state = MBEDTLS_SSL_SERVER_KEY_EXCHANGE;
+    }
+    else
+    {
+        ssl->state = MBEDTLS_SSL_INVALID;
+    }
 
     if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
     {
@@ -7129,7 +7263,7 @@
  * indicating whether a Certificate message is expected or not.
  */
 #define SSL_CERTIFICATE_EXPECTED 0
-#define SSL_CERTIFICATE_SKIP     1
+#define SSL_CERTIFICATE_SKIP     0xff
 static int ssl_parse_certificate_coordinate( mbedtls_ssl_context *ssl,
                                              int authmode )
 {
@@ -7163,19 +7297,24 @@
 }
 
 static int ssl_parse_certificate_verify( mbedtls_ssl_context *ssl,
-                                         int authmode,
+                                         volatile int authmode,
                                          mbedtls_x509_crt *chain,
                                          void *rs_ctx )
 {
-    int verify_ret;
+    volatile int verify_ret = MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE;
+    volatile int ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR;
+    volatile int flow_counter = 0;
     mbedtls_ssl_ciphersuite_handle_t ciphersuite_info =
         mbedtls_ssl_handshake_get_ciphersuite( ssl->handshake );
     mbedtls_x509_crt *ca_chain;
     mbedtls_x509_crl *ca_crl;
 
     if( authmode == MBEDTLS_SSL_VERIFY_NONE )
+    {
         return( 0 );
+    }
 
+    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse certificate verify" ) );
 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
     if( ssl->handshake->sni_ca_chain != NULL )
     {
@@ -7205,9 +7344,22 @@
 #endif /* MBEDTLS_X509_REMOVE_VERIFY_CALLBACK */
         rs_ctx );
 
+    if( verify_ret == 0 )
+    {
+        mbedtls_platform_enforce_volatile_reads();
+        if( verify_ret == 0 )
+        {
+            flow_counter++;
+        }
+        else
+        {
+            return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
+        }
+    }
     if( verify_ret != 0 )
     {
         MBEDTLS_SSL_DEBUG_RET( 1, "x509_verify_cert", verify_ret );
+        flow_counter++;
     }
 
 #if defined(MBEDTLS_SSL__ECP_RESTARTABLE)
@@ -7221,7 +7373,6 @@
 
 #if defined(MBEDTLS_ECP_C) || defined(MBEDTLS_USE_TINYCRYPT)
     {
-        int ret;
 #if defined(MBEDTLS_USE_TINYCRYPT)
         ret = mbedtls_ssl_check_curve_uecc( ssl, MBEDTLS_UECC_DP_SECP256R1 );
 #else /* MBEDTLS_USE_TINYCRYPT */
@@ -7249,16 +7400,27 @@
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate (EC key curve)" ) );
             if( verify_ret == 0 )
                 verify_ret = MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE;
+            flow_counter++;
+        }
+        if( ret == 0 )
+        {
+            flow_counter++;
         }
     }
 #endif /* MBEDTLS_ECP_C || MEDTLS_USE_TINYCRYPT */
 
-    if( mbedtls_ssl_check_cert_usage( chain,
+    ret = mbedtls_ssl_check_cert_usage( chain,
                                       ciphersuite_info,
                                       ( mbedtls_ssl_conf_get_endpoint( ssl->conf ) ==
                                         MBEDTLS_SSL_IS_CLIENT ),
-                                      &ssl->session_negotiate->verify_result ) != 0 )
+                                      &ssl->session_negotiate->verify_result );
+    if( ret == 0 )
     {
+        flow_counter++;
+    }
+    else
+    {
+        flow_counter++;
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate (usage extensions)" ) );
         if( verify_ret == 0 )
             verify_ret = MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE;
@@ -7274,13 +7436,31 @@
         ( verify_ret == MBEDTLS_ERR_X509_CERT_VERIFY_FAILED ||
           verify_ret == MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE ) )
     {
-        verify_ret = 0;
+        mbedtls_platform_enforce_volatile_reads();
+        if( authmode == MBEDTLS_SSL_VERIFY_OPTIONAL &&
+            ( verify_ret == MBEDTLS_ERR_X509_CERT_VERIFY_FAILED ||
+              verify_ret == MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE ) )
+        {
+            verify_ret = 0;
+            flow_counter++;
+        }
+        else
+        {
+            return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
+        }
+    } else {
+        flow_counter++;
     }
 
     if( ca_chain == NULL && authmode == MBEDTLS_SSL_VERIFY_REQUIRED )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no CA chain" ) );
         verify_ret = MBEDTLS_ERR_SSL_CA_CHAIN_REQUIRED;
+        flow_counter++;
+    }
+    else
+    {
+        flow_counter++;
     }
 
     if( verify_ret != 0 )
@@ -7315,6 +7495,32 @@
         mbedtls_ssl_pend_fatal_alert( ssl, alert );
     }
 
+    if( verify_ret == 0 &&
+#if defined(MBEDTLS_ECP_C) || defined(MBEDTLS_USE_TINYCRYPT)
+        flow_counter == 5 )
+#else
+        flow_counter == 4 )
+#endif
+    {
+        mbedtls_platform_enforce_volatile_reads();
+        if( verify_ret == 0 &&
+#if defined(MBEDTLS_ECP_C) || defined(MBEDTLS_USE_TINYCRYPT)
+            flow_counter == 5 )
+#else
+            flow_counter == 4 )
+#endif
+        {
+            MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> PEER AUTHENTICATED" ) );
+            ssl->handshake->peer_authenticated = MBEDTLS_SSL_FI_FLAG_SET;
+        }
+        else
+        {
+            return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
+        }
+    } else {
+        MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> PEER NOT AUTHENTICATED, %d", flow_counter));
+    }
+
 #if defined(MBEDTLS_DEBUG_C)
     if( ssl->session_negotiate->verify_result != 0 )
     {
@@ -7523,7 +7729,20 @@
 exit:
 
     if( ret == 0 )
-        ssl->state++;
+    {
+        if( ssl->state == MBEDTLS_SSL_CLIENT_CERTIFICATE )
+        {
+            ssl->state = MBEDTLS_SSL_CLIENT_KEY_EXCHANGE;
+        }
+        else if( ssl->state == MBEDTLS_SSL_SERVER_CERTIFICATE )
+        {
+            ssl->state = MBEDTLS_SSL_SERVER_KEY_EXCHANGE;
+        }
+        else
+        {
+            ssl->state = MBEDTLS_SSL_INVALID;
+        }
+    }
 
 #if defined(MBEDTLS_SSL__ECP_RESTARTABLE)
     if( ret == MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS )
@@ -7553,7 +7772,18 @@
     ssl->out_msglen  = 1;
     ssl->out_msg[0]  = 1;
 
-    ssl->state++;
+    if( ssl->state == MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC )
+    {
+        ssl->state = MBEDTLS_SSL_CLIENT_FINISHED;
+    }
+    else if( ssl->state == MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC )
+    {
+        ssl->state = MBEDTLS_SSL_SERVER_FINISHED;
+    }
+    else
+    {
+        ssl->state = MBEDTLS_SSL_INVALID;
+    }
 
     if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
     {
@@ -7636,7 +7866,18 @@
     }
 #endif
 
-    ssl->state++;
+    if( ssl->state == MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC )
+    {
+        ssl->state = MBEDTLS_SSL_CLIENT_FINISHED;
+    }
+    else if( ssl->state == MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC )
+    {
+        ssl->state = MBEDTLS_SSL_SERVER_FINISHED;
+    }
+    else
+    {
+        ssl->state = MBEDTLS_SSL_INVALID;
+    }
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse change cipher spec" ) );
 
@@ -7685,8 +7926,21 @@
     MBEDTLS_SSL_DEBUG_MSG( 3, ( "<= handshake wrapup: final free" ) );
 }
 
-void mbedtls_ssl_handshake_wrapup( mbedtls_ssl_context *ssl )
+int mbedtls_ssl_handshake_wrapup( mbedtls_ssl_context *ssl )
 {
+    volatile int ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR;
+
+#if defined(MBEDTLS_SSL_SRV_C) && defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
+    volatile const int authmode = ssl->handshake->sni_authmode != MBEDTLS_SSL_VERIFY_UNSET
+                       ? ssl->handshake->sni_authmode
+                       : mbedtls_ssl_conf_get_authmode( ssl->conf );
+#else
+    volatile const int authmode = mbedtls_ssl_conf_get_authmode( ssl->conf );
+#endif
+#if defined(MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED)
+    volatile int crt_expected = SSL_CERTIFICATE_EXPECTED;
+    crt_expected = ssl_parse_certificate_coordinate( ssl, authmode );
+#endif
     MBEDTLS_SSL_DEBUG_MSG( 3, ( "=> handshake wrapup" ) );
 
 #if defined(MBEDTLS_SSL_RENEGOTIATION)
@@ -7720,13 +7974,102 @@
      */
     if( ssl->conf->f_set_cache != NULL &&
         ssl->session->id_len != 0 &&
-        ssl->handshake->resume == 0 )
+        ssl->handshake->resume == MBEDTLS_SSL_FI_FLAG_UNSET )
     {
         if( ssl->conf->f_set_cache( ssl->conf->p_cache, ssl->session ) != 0 )
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "cache did not store session" ) );
     }
 #endif /* MBEDTLS_SSL_SRV_C && !MBEDTLS_SSL_NO_SESSION_CACHE */
 
+    if( authmode == MBEDTLS_SSL_VERIFY_NONE ||
+        authmode == MBEDTLS_SSL_VERIFY_OPTIONAL ||
+#if defined(MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED)
+        crt_expected == SSL_CERTIFICATE_SKIP )
+#else
+        1 )
+#endif
+    {
+        mbedtls_platform_enforce_volatile_reads();
+        if( authmode == MBEDTLS_SSL_VERIFY_NONE ||
+            authmode == MBEDTLS_SSL_VERIFY_OPTIONAL ||
+#if defined(MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED)
+            crt_expected == SSL_CERTIFICATE_SKIP )
+#else
+            1 )
+#endif
+        {
+            ssl->handshake->peer_authenticated = MBEDTLS_SSL_FI_FLAG_SET;
+        }
+        else
+        {
+            ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
+            goto cleanup;
+        }
+    }
+
+#if !defined(MBEDTLS_SSL_NO_SESSION_RESUMPTION)
+    if( ssl->handshake->resume == MBEDTLS_SSL_FI_FLAG_SET )
+    {
+        mbedtls_platform_enforce_volatile_reads();
+        if( ssl->handshake->resume == MBEDTLS_SSL_FI_FLAG_SET )
+        {
+            /* When doing session resume, no premaster or peer authentication */
+            ssl->handshake->peer_authenticated = MBEDTLS_SSL_FI_FLAG_SET;
+            ssl->handshake->premaster_generated = MBEDTLS_SSL_FI_FLAG_SET;
+        }
+        else
+        {
+            ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
+            goto cleanup;
+        }
+    }
+#endif
+
+    if( ssl->handshake->peer_authenticated == MBEDTLS_SSL_FI_FLAG_SET )
+    {
+        mbedtls_platform_enforce_volatile_reads();
+        if( ssl->handshake->peer_authenticated == MBEDTLS_SSL_FI_FLAG_SET )
+        {
+            ret = 0;
+        }
+        else
+        {
+            ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
+            goto cleanup;
+        }
+    }
+    else
+    {
+        ret = MBEDTLS_ERR_SSL_PEER_VERIFY_FAILED;
+        goto cleanup;
+    }
+
+    if( ssl->handshake->hello_random_set == MBEDTLS_SSL_FI_FLAG_SET &&
+        ssl->handshake->key_derivation_done == MBEDTLS_SSL_FI_FLAG_SET &&
+        ssl->handshake->premaster_generated == MBEDTLS_SSL_FI_FLAG_SET )
+    {
+        mbedtls_platform_enforce_volatile_reads();
+        if( ssl->handshake->hello_random_set == MBEDTLS_SSL_FI_FLAG_SET &&
+            ssl->handshake->key_derivation_done == MBEDTLS_SSL_FI_FLAG_SET &&
+            ssl->handshake->premaster_generated == MBEDTLS_SSL_FI_FLAG_SET )
+        {
+            ret = 0;
+        }
+        else
+        {
+            ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
+            goto cleanup;
+        }
+    }
+    else
+    {
+        MBEDTLS_SSL_DEBUG_MSG( 3, ( "hello random %d", ssl->handshake->hello_random_set ) );
+        MBEDTLS_SSL_DEBUG_MSG( 3, ( "key_derivation_done %d", ssl->handshake->key_derivation_done ) );
+        MBEDTLS_SSL_DEBUG_MSG( 3, ( "premaster_generated %d", ssl->handshake->premaster_generated ) );
+        ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR;
+    }
+
+cleanup:
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
     if( MBEDTLS_SSL_TRANSPORT_IS_DTLS( ssl->conf->transport ) &&
         ssl->handshake->flight != NULL )
@@ -7742,9 +8085,10 @@
 #endif
         ssl_handshake_wrapup_free_hs_transform( ssl );
 
-    ssl->state++;
+    ssl->state = MBEDTLS_SSL_HANDSHAKE_OVER;
 
     MBEDTLS_SSL_DEBUG_MSG( 3, ( "<= handshake wrapup" ) );
+    return ret;
 }
 
 int mbedtls_ssl_write_finished( mbedtls_ssl_context *ssl )
@@ -7785,7 +8129,7 @@
      * In case of session resuming, invert the client and server
      * ChangeCipherSpec messages order.
      */
-    if( ssl->handshake->resume != 0 )
+    if( ssl->handshake->resume == MBEDTLS_SSL_FI_FLAG_SET )
     {
 #if defined(MBEDTLS_SSL_CLI_C)
         if( mbedtls_ssl_conf_get_endpoint( ssl->conf ) ==
@@ -7804,7 +8148,20 @@
     }
     else
 #endif /* !MBEDTLS_SSL_NO_SESSION_RESUMPTION */
-        ssl->state++;
+    {
+        if( ssl->state == MBEDTLS_SSL_CLIENT_FINISHED )
+        {
+            ssl->state = MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC;
+        }
+        else if( ssl->state == MBEDTLS_SSL_SERVER_FINISHED )
+        {
+            ssl->state = MBEDTLS_SSL_FLUSH_BUFFERS;
+        }
+        else
+        {
+            ssl->state = MBEDTLS_SSL_INVALID;
+        }
+    }
 
     /*
      * Switch to our negotiated transform and session parameters for outbound
@@ -7951,7 +8308,7 @@
 #endif
 
 #if !defined(MBEDTLS_SSL_NO_SESSION_RESUMPTION)
-    if( ssl->handshake->resume != 0 )
+    if( ssl->handshake->resume == MBEDTLS_SSL_FI_FLAG_SET )
     {
 #if defined(MBEDTLS_SSL_CLI_C)
         if( mbedtls_ssl_conf_get_endpoint( ssl->conf ) == MBEDTLS_SSL_IS_CLIENT )
@@ -7964,7 +8321,20 @@
     }
     else
 #endif /* !MBEDTLS_SSL_NO_SESSION_RESUMPTION */
-        ssl->state++;
+    {
+        if( ssl->state == MBEDTLS_SSL_CLIENT_FINISHED )
+        {
+            ssl->state = MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC;
+        }
+        else if( ssl->state == MBEDTLS_SSL_SERVER_FINISHED )
+        {
+            ssl->state = MBEDTLS_SSL_FLUSH_BUFFERS;
+        }
+        else
+        {
+            ssl->state = MBEDTLS_SSL_INVALID;
+        }
+    }
 
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
     if( MBEDTLS_SSL_TRANSPORT_IS_DTLS( ssl->conf->transport ) )
@@ -8667,7 +9037,7 @@
                                           session ) ) != 0 )
         return( ret );
 
-    ssl->handshake->resume = 1;
+    ssl->handshake->resume = MBEDTLS_SSL_FI_FLAG_SET;
 
     return( 0 );
 }