Merge remote-tracking branch 'restricted/pr/601' into baremetal-proposed

* restricted/pr/601: (27 commits)
  Fix compile-time guard for optional field in struct
  Move code to reduce probability of conflicts
  Fix typos caught by check-names.sh
  Clarify conditions related to resumption in client
  Introduce getter function for renego_status
  Add getter function for handshake->resume
  Remove now-redundant code
  Remove cache callbacks from config on client
  Fix a few style issues
  Expand documentation of new options a bit
  Fix renaming oversight in documentation
  Remove backticks in doxygen in config.h
  Declare dependency on tickets for two ssl-opt.sh tests
  Exclude new negative options from config.pl full
  Restore config.h defaults
  Address review comments
  Fix ssl_cli resumption guards
  Fix check-files, check-names and check-generated-features
  Add test to all.sh
  Add changelog entry
  ...

ChangeLog

@@ -38,24 +38,12 @@ Features
      ServerHello.
    * Add new configuration option MBEDTLS_SSL_PROTO_NO_TLS that enables code
      size savings in configurations where only DTLS is used.
-
+   * Add new configuration option MBEDTLS_SSL_NO_SESSION_CACHE that enables
-API Changes
+     code size savings in configurations where cache-based session resumption is
-   * Add a new X.509 API call `mbedtls_x509_parse_der_nocopy()`.
+     not used.
-     See the Features section for more information.
+   * Add new configuration option MBEDTLS_SSL_NO_SESSION_RESUMPTION that
-   * Allow to opt in to the removal the API mbedtls_ssl_get_peer_cert()
+     enables code size savings in configurations where no form of session
-     for the benefit of saving RAM, by disabling the new compile-time
+     resumption is used.
-     option MBEDTLS_SSL_KEEP_PEER_CERTIFICATE (enabled by default for
-     API stability). Disabling this option makes mbedtls_ssl_get_peer_cert()
-     always return NULL, and removes the peer_cert field from the
-     mbedtls_ssl_session structure which otherwise stores the peer's
-     certificate.
-   * Add a new compile-time option `MBEDTLS_X509_ON_DEMAND_PARSING`,
-     disabled by default, which allows to parse and cache X.509 CRTs
-     on demand only, at the benefit of lower RAM usage. Enabling
-     this option breaks the structure API of X.509 in that most
-     fields of `mbedtls_x509_crt` are removed, but it keeps the
-     X.509 function API. See the API changes section as well as
-     the documentation in `config.h` for more information.
 
 Bugfix
    * Server's RSA certificate in certs.c was SHA-1 signed. In the default
@@ -105,6 +93,24 @@ Changes
      improve clarity. Fixes #2258.
    * Replace multiple uses of MD2 by SHA-256 in X.509 test suite. Fixes #821.
 
+API Changes
+   * Add a new X.509 API call `mbedtls_x509_parse_der_nocopy()`.
+     See the Features section for more information.
+   * Allow to opt in to the removal the API mbedtls_ssl_get_peer_cert()
+     for the benefit of saving RAM, by disabling the new compile-time
+     option MBEDTLS_SSL_KEEP_PEER_CERTIFICATE (enabled by default for
+     API stability). Disabling this option makes mbedtls_ssl_get_peer_cert()
+     always return NULL, and removes the peer_cert field from the
+     mbedtls_ssl_session structure which otherwise stores the peer's
+     certificate.
+   * Add a new compile-time option `MBEDTLS_X509_ON_DEMAND_PARSING`,
+     disabled by default, which allows to parse and cache X.509 CRTs
+     on demand only, at the benefit of lower RAM usage. Enabling
+     this option breaks the structure API of X.509 in that most
+     fields of `mbedtls_x509_crt` are removed, but it keeps the
+     X.509 function API. See the API changes section as well as
+     the documentation in `config.h` for more information.
+
 = mbed TLS 2.16.1 branch released 2019-03-19
 
 Features

configs/baremetal.h

@@ -71,6 +71,8 @@
 #define MBEDTLS_SSL_TLS_C
 #define MBEDTLS_SSL_PROTO_TLS1_2
 #define MBEDTLS_SSL_EXTENDED_MASTER_SECRET
+#define MBEDTLS_SSL_NO_SESSION_CACHE
+#define MBEDTLS_SSL_NO_SESSION_RESUMPTION
 #define MBEDTLS_SSL_COOKIE_C
 #define MBEDTLS_SSL_PROTO_DTLS
 #define MBEDTLS_SSL_PROTO_NO_TLS

include/mbedtls/check_config.h

@@ -671,6 +671,16 @@
 #error "MBEDTLS_SSL_SERVER_NAME_INDICATION defined, but not all prerequisites"
 #endif
 
+#if defined(MBEDTLS_SSL_SESSION_TICKETS) &&  \
+    defined(MBEDTLS_SSL_NO_SESSION_RESUMPTION)
+#error "MBEDTLS_SSL_SESSION_TICKETS cannot be defined with MBEDTLS_SSL_NO_SESSION_RESUMPTION"
+#endif
+
+#if !defined(MBEDTLS_SSL_NO_SESSION_CACHE) &&  \
+    defined(MBEDTLS_SSL_NO_SESSION_RESUMPTION)
+#error "MBEDTLS_SSL_NO_SESSION_CACHE needs to be defined with MBEDTLS_SSL_NO_SESSION_RESUMPTION"
+#endif
+
 #if defined(MBEDTLS_THREADING_PTHREAD)
 #if !defined(MBEDTLS_THREADING_C) || defined(MBEDTLS_THREADING_IMPL)
 #error "MBEDTLS_THREADING_PTHREAD defined, but not all prerequisites"

include/mbedtls/config.h

@@ -1278,8 +1278,8 @@
  * which allows to identify DTLS connections across changes
  * in the underlying transport.
  *
- * Setting this option enables the SSL APIs `mbedtls_ssl_set_cid()`,
+ * Setting this option enables the SSL APIs mbedtls_ssl_set_cid(),
- * `mbedtls_ssl_get_peer_cid()` and `mbedtls_ssl_conf_cid()`.
+ * mbedtls_ssl_get_peer_cid() and mbedtls_ssl_conf_cid().
  * See the corresponding documentation for more information.
  *
  * \warning The Connection ID extension is still in draft state.
@@ -1664,10 +1664,63 @@
  * tickets, including authenticated encryption and key management. Example
  * callbacks are provided by MBEDTLS_SSL_TICKET_C.
  *
- * Comment this macro to disable support for SSL session tickets
+ * Requires: !MBEDTLS_SSL_NO_SESSION_RESUMPTION
+ *
+ * Comment this macro to disable support for SSL session tickets.
  */
 #define MBEDTLS_SSL_SESSION_TICKETS
 
+/**
+ * \def MBEDTLS_SSL_NO_SESSION_CACHE
+ *
+ * Disable support for cache based session resumption. This is useful to
+ * reduce code size in configurations where cache-based session resumption is
+ * not used.
+ *
+ * This option is only about the server-side support of the session caches.
+ * Client will only need !MBEDTLS_SSL_NO_SESSION_RESUMPTION to support
+ * cache based session resumption.
+ *
+ * Server-side, you also need to provide callbacks for storing and reading
+ * sessions from cache. Example callbacks are provided by MBEDTLS_SSL_CACHE_C.
+ *
+ * If MBEDTLS_SSL_NO_SESSION_RESUMPTION is defined, this needs to be defined
+ * as well.
+ *
+ * Uncomment this macro to disable support for SSL session cache.
+ */
+//#define MBEDTLS_SSL_NO_SESSION_CACHE
+
+/**
+ * \def MBEDTLS_SSL_NO_SESSION_RESUMPTION
+ *
+ * Disable support for session resumption. This is useful to reduce code size
+ * in configurations where no form of session resumption is used.
+ *
+ * \note Session resumption is part of the TLS standard, disabling this
+ * option means that the full implementation of the standard is no longer
+ * used. This shouldn't cause any interoperability issues as the standard
+ * mandates that peers who want to resume a session need to be prepared to
+ * fall back to a full handshake.
+ *
+ * When this flag is enabled, following needs to be true:
+ *     MBEDTLS_SSL_NO_SESSION_CACHE enabled
+ *     MBEDTLS_SSL_SESSION_TICKETS disabled
+ *
+ * Client-side, this is enough to enable support for cache-based session
+ * resumption (as defined by the TLS standard); for ticket-based resumption
+ * you'll also need to enable MBEDTLS_SSL_SESSION_TICKETS.
+ *
+ * Server-side, this option is only useful in conjunction with at least
+ * one of !MBEDTLS_SSL_NO_SESSION_CACHE or MBEDTLS_SSL_SESSION_TICKETS.
+ * Each one of these additionally requires an implementation of the cache
+ * or tickets, examples of which are provided by MBEDTLS_SSL_CACHE_C
+ * and MBEDTLS_SSL_TICKET_C respectively.
+ *
+ * Uncomment this macro to disable support for SSL session resumption.
+ */
+//#define MBEDTLS_SSL_NO_SESSION_RESUMPTION
+
 /**
  * \def MBEDTLS_SSL_EXPORT_KEYS
  *

include/mbedtls/ssl.h

@@ -906,11 +906,13 @@ struct mbedtls_ssl_config
     int  (*f_rng)(void *, unsigned char *, size_t);
     void *p_rng;                    /*!< context for the RNG function       */
 
+#if defined(MBEDTLS_SSL_SRV_C) && !defined(MBEDTLS_SSL_NO_SESSION_CACHE)
     /** Callback to retrieve a session from the cache                       */
     int (*f_get_cache)(void *, mbedtls_ssl_session *);
     /** Callback to store a session into the cache                          */
     int (*f_set_cache)(void *, const mbedtls_ssl_session *);
     void *p_cache;                  /*!< context for cache callbacks        */
+#endif /* MBEDTLS_SSL_SRV_C && !MBEDTLS_SSL_NO_SESSION_CACHE */
 
 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
     /** Callback for setting cert according to SNI extension                */
@@ -2129,7 +2131,7 @@ void mbedtls_ssl_set_datagram_packing( mbedtls_ssl_context *ssl,
 void mbedtls_ssl_conf_handshake_timeout( mbedtls_ssl_config *conf, uint32_t min, uint32_t max );
 #endif /* MBEDTLS_SSL_PROTO_DTLS */
 
-#if defined(MBEDTLS_SSL_SRV_C)
+#if defined(MBEDTLS_SSL_SRV_C) && !defined(MBEDTLS_SSL_NO_SESSION_CACHE)
 /**
  * \brief          Set the session cache callbacks (server-side only)
  *                 If not set, no session resuming is done (except if session
@@ -2171,9 +2173,9 @@ void mbedtls_ssl_conf_session_cache( mbedtls_ssl_config *conf,
         void *p_cache,
         int (*f_get_cache)(void *, mbedtls_ssl_session *),
         int (*f_set_cache)(void *, const mbedtls_ssl_session *) );
-#endif /* MBEDTLS_SSL_SRV_C */
+#endif /* MBEDTLS_SSL_SRV_C && !MBEDTLS_SSL_NO_SESSION_CACHE */
 
-#if defined(MBEDTLS_SSL_CLI_C)
+#if defined(MBEDTLS_SSL_CLI_C) && !defined(MBEDTLS_SSL_NO_SESSION_RESUMPTION)
 /**
  * \brief          Request resumption of session (client-side only)
  *                 Session data is copied from presented session structure.
@@ -2189,7 +2191,7 @@ void mbedtls_ssl_conf_session_cache( mbedtls_ssl_config *conf,
  * \sa             mbedtls_ssl_get_session()
  */
 int mbedtls_ssl_set_session( mbedtls_ssl_context *ssl, const mbedtls_ssl_session *session );
-#endif /* MBEDTLS_SSL_CLI_C */
+#endif /* MBEDTLS_SSL_CLI_C && !MBEDTLS_SSL_NO_SESSION_RESUMPTION */
 
 /**
  * \brief          Load serialized session data into a session structure.

include/mbedtls/ssl_internal.h

@@ -509,7 +509,9 @@ struct mbedtls_ssl_handshake_params
     unsigned char premaster[MBEDTLS_PREMASTER_SIZE];
                                         /*!<  premaster secret        */
 
+#if !defined(MBEDTLS_SSL_NO_SESSION_RESUMPTION)
     int resume;                         /*!<  session resume indicator*/
+#endif /* !MBEDTLS_SSL_NO_SESSION_RESUMPTION */
     int max_major_ver;                  /*!< max. major version client*/
     int max_minor_ver;                  /*!< max. minor version client*/
     int cli_exts;                       /*!< client extension presence*/
@@ -1080,6 +1082,33 @@ int mbedtls_ssl_decrypt_buf( mbedtls_ssl_context *ssl,
                              mbedtls_record *rec );
 
 
+/*
+ * Accessor functions for optional fields of various structures
+ */
+
+static inline int mbedtls_ssl_handshake_get_resume(
+        const mbedtls_ssl_handshake_params *handshake )
+{
+#if !defined(MBEDTLS_SSL_NO_SESSION_RESUMPTION)
+    return( handshake->resume );
+#else
+    (void) handshake;
+    return( 0 );
+#endif
+}
+
+static inline int mbedtls_ssl_get_renego_status(
+        const mbedtls_ssl_context *ssl )
+{
+#if defined(MBEDTLS_SSL_RENEGOTIATION)
+    return( ssl->renego_status );
+#else
+    (void) ssl;
+    return( MBEDTLS_SSL_INITIAL_HANDSHAKE );
+#endif
+}
+
+
 /*
  * Getter functions for fields in mbedtls_ssl_config which may
  * be fixed at compile time via one of MBEDTLS_SSL_SSL_CONF_XXX.

library/ssl_cli.c

@@ -828,9 +828,7 @@ static int ssl_write_client_hello( mbedtls_ssl_context *ssl )
         return( MBEDTLS_ERR_SSL_NO_RNG );
     }
 
-#if defined(MBEDTLS_SSL_RENEGOTIATION)
+    if( mbedtls_ssl_get_renego_status( ssl ) == MBEDTLS_SSL_INITIAL_HANDSHAKE )
-    if( ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE )
-#endif
     {
         ssl->major_ver = ssl->conf->min_major_ver;
         ssl->minor_ver = ssl->conf->min_minor_ver;
@@ -882,36 +880,40 @@ static int ssl_write_client_hello( mbedtls_ssl_context *ssl )
      *   ..   . ..    extensions length (2 bytes)
      *   ..   . ..    extensions
      */
-    n = ssl->session_negotiate->id_len;
 
-    if( n < 16 || n > 32 ||
+    /*
-#if defined(MBEDTLS_SSL_RENEGOTIATION)
+     * We'll write a session of non-zero length if resumption was requested
-        ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE ||
+     * by the user, we're not renegotiating, and the session ID is of
-#endif
+     * appropriate length. Otherwise make the length 0 (for now, see next code
-        ssl->handshake->resume == 0 )
+     * block for behaviour with tickets).
+     */
+    if( mbedtls_ssl_handshake_get_resume( ssl->handshake ) == 0 ||
+        mbedtls_ssl_get_renego_status( ssl ) != MBEDTLS_SSL_INITIAL_HANDSHAKE ||
+        ssl->session_negotiate->id_len < 16 ||
+        ssl->session_negotiate->id_len > 32 )
     {
         n = 0;
     }
+    else
+    {
+        n = ssl->session_negotiate->id_len;
+    }
 
 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
     /*
      * RFC 5077 section 3.4: "When presenting a ticket, the client MAY
      * generate and include a Session ID in the TLS ClientHello."
      */
-#if defined(MBEDTLS_SSL_RENEGOTIATION)
+    if( mbedtls_ssl_get_renego_status( ssl ) == MBEDTLS_SSL_INITIAL_HANDSHAKE &&
-    if( ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE )
+        ssl->session_negotiate->ticket != NULL &&
-#endif
+        ssl->session_negotiate->ticket_len != 0 )
     {
-        if( ssl->session_negotiate->ticket != NULL &&
+        ret = ssl->conf->f_rng( ssl->conf->p_rng, ssl->session_negotiate->id, 32 );
-                ssl->session_negotiate->ticket_len != 0 )
-        {
-            ret = ssl->conf->f_rng( ssl->conf->p_rng, ssl->session_negotiate->id, 32 );
 
-            if( ret != 0 )
+        if( ret != 0 )
-                return( ret );
+            return( ret );
 
-            ssl->session_negotiate->id_len = n = 32;
+        ssl->session_negotiate->id_len = n = 32;
-        }
     }
 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
 
@@ -985,9 +987,7 @@ static int ssl_write_client_hello( mbedtls_ssl_context *ssl )
     /*
      * Add TLS_EMPTY_RENEGOTIATION_INFO_SCSV
      */
-#if defined(MBEDTLS_SSL_RENEGOTIATION)
+    if( mbedtls_ssl_get_renego_status( ssl ) == MBEDTLS_SSL_INITIAL_HANDSHAKE )
-    if( ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE )
-#endif
     {
         MBEDTLS_SSL_DEBUG_MSG( 3, ( "adding EMPTY_RENEGOTIATION_INFO_SCSV" ) );
         *p++ = (unsigned char)( MBEDTLS_SSL_EMPTY_RENEGOTIATION_INFO >> 8 );
@@ -1797,28 +1797,30 @@ static int ssl_parse_server_hello( mbedtls_ssl_context *ssl )
 
     /*
      * Check if the session can be resumed
+     *
+     * We're only resuming a session if it was requested (handshake->resume
+     * already set to 1 by mbedtls_ssl_set_session()), and further conditions
+     * are satisfied (not renegotiating, ID and ciphersuite match, etc).
+     *
+     * Update handshake->resume to the value it will keep for the rest of the
+     * handshake, and that will be used to determine the relative order
+     * client/server last flights, as well as in handshake_wrapup().
      */
-    if( ssl->handshake->resume == 0 || n == 0 ||
+#if !defined(MBEDTLS_SSL_NO_SESSION_RESUMPTION)
-#if defined(MBEDTLS_SSL_RENEGOTIATION)
+    if( n == 0 ||
-        ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE ||
+        mbedtls_ssl_get_renego_status( ssl ) != MBEDTLS_SSL_INITIAL_HANDSHAKE ||
-#endif
         ssl->session_negotiate->ciphersuite != i ||
         ssl->session_negotiate->compression != comp ||
         ssl->session_negotiate->id_len != n ||
         memcmp( ssl->session_negotiate->id, buf + 35, n ) != 0 )
     {
-        ssl->state++;
         ssl->handshake->resume = 0;
-#if defined(MBEDTLS_HAVE_TIME)
-        ssl->session_negotiate->start = mbedtls_time( NULL );
-#endif
-        ssl->session_negotiate->ciphersuite = i;
-        ssl->session_negotiate->compression = comp;
-        ssl->session_negotiate->id_len = n;
-        memcpy( ssl->session_negotiate->id, buf + 35, n );
     }
-    else
+#endif /* !MBEDTLS_SSL_NO_SESSION_RESUMPTION */
+
+    if( mbedtls_ssl_handshake_get_resume( ssl->handshake ) == 1 )
     {
+        /* Resume a session */
         ssl->state = MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC;
 
         if( ( ret = mbedtls_ssl_derive_keys( ssl ) ) != 0 )
@@ -1829,9 +1831,21 @@ static int ssl_parse_server_hello( mbedtls_ssl_context *ssl )
             return( ret );
         }
     }
+    else
+    {
+        /* Start a new session */
+        ssl->state++;
+#if defined(MBEDTLS_HAVE_TIME)
+        ssl->session_negotiate->start = mbedtls_time( NULL );
+#endif
+        ssl->session_negotiate->ciphersuite = i;
+        ssl->session_negotiate->compression = comp;
+        ssl->session_negotiate->id_len = n;
+        memcpy( ssl->session_negotiate->id, buf + 35, n );
+    }
 
     MBEDTLS_SSL_DEBUG_MSG( 3, ( "%s session has been resumed",
-                   ssl->handshake->resume ? "a" : "no" ) );
+               mbedtls_ssl_handshake_get_resume( ssl->handshake ) ? "a" : "no" ) );
 
     MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, chosen ciphersuite: %04x", i ) );
     MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, compress alg.: %d", buf[37 + n] ) );

library/ssl_srv.c

@@ -1341,16 +1341,12 @@ read_record_header:
      * otherwise read it ourselves manually in order to support SSLv2
      * ClientHello, which doesn't use the same record layer format.
      */
-#if defined(MBEDTLS_SSL_RENEGOTIATION)
+    if( mbedtls_ssl_get_renego_status( ssl ) == MBEDTLS_SSL_INITIAL_HANDSHAKE &&
-    if( ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE )
+        ( ret = mbedtls_ssl_fetch_input( ssl, 5 ) ) != 0 )
-#endif
     {
-        if( ( ret = mbedtls_ssl_fetch_input( ssl, 5 ) ) != 0 )
+        /* No alert on a read error. */
-        {
+        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_fetch_input", ret );
-            /* No alert on a read error. */
+        return( ret );
-            MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_fetch_input", ret );
-            return( ret );
-        }
     }
 
     buf = ssl->in_hdr;
@@ -1405,11 +1401,8 @@ read_record_header:
     /* For DTLS if this is the initial handshake, remember the client sequence
      * number to use it in our next message (RFC 6347 4.2.1) */
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
-    if( MBEDTLS_SSL_TRANSPORT_IS_DTLS( ssl->conf->transport )
+    if( MBEDTLS_SSL_TRANSPORT_IS_DTLS( ssl->conf->transport ) &&
-#if defined(MBEDTLS_SSL_RENEGOTIATION)
+        mbedtls_ssl_get_renego_status( ssl ) == MBEDTLS_SSL_INITIAL_HANDSHAKE )
-        && ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE
-#endif
-        )
     {
         /* Epoch should be 0 for initial handshakes */
         if( ssl->in_ctr[0] != 0 || ssl->in_ctr[1] != 0 )
@@ -1670,11 +1663,8 @@ read_record_header:
                        buf + cookie_offset + 1, cookie_len );
 
 #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY)
-        if( ssl->conf->f_cookie_check != NULL
+        if( ssl->conf->f_cookie_check != NULL &&
-#if defined(MBEDTLS_SSL_RENEGOTIATION)
+            mbedtls_ssl_get_renego_status( ssl ) == MBEDTLS_SSL_INITIAL_HANDSHAKE )
-            && ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE
-#endif
-            )
         {
             if( ssl->conf->f_cookie_check( ssl->conf->p_cookie,
                                      buf + cookie_offset + 1, cookie_len,
@@ -2691,15 +2681,14 @@ static int ssl_write_server_hello( mbedtls_ssl_context *ssl )
 
     MBEDTLS_SSL_DEBUG_BUF( 3, "server hello, random bytes", buf + 6, 32 );
 
+#if !defined(MBEDTLS_SSL_NO_SESSION_CACHE)
     /*
      * Resume is 0  by default, see ssl_handshake_init().
      * It may be already set to 1 by ssl_parse_session_ticket_ext().
      * If not, try looking up session ID in our cache.
      */
-    if( ssl->handshake->resume == 0 &&
+    if( mbedtls_ssl_handshake_get_resume( ssl->handshake ) == 0 &&
-#if defined(MBEDTLS_SSL_RENEGOTIATION)
+        mbedtls_ssl_get_renego_status( ssl ) == MBEDTLS_SSL_INITIAL_HANDSHAKE &&
-        ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE &&
-#endif
         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 )
@@ -2707,8 +2696,25 @@ static int ssl_write_server_hello( mbedtls_ssl_context *ssl )
         MBEDTLS_SSL_DEBUG_MSG( 3, ( "session successfully restored from cache" ) );
         ssl->handshake->resume = 1;
     }
+#endif /* !MBEDTLS_SSL_NO_SESSION_CACHE */
 
-    if( ssl->handshake->resume == 0 )
+#if !defined(MBEDTLS_SSL_NO_SESSION_RESUMPTION)
+    if( mbedtls_ssl_handshake_get_resume( ssl->handshake ) == 1 )
+    {
+        /*
+         * Resuming a session
+         */
+        n = ssl->session_negotiate->id_len;
+        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 );
+            return( ret );
+        }
+    }
+    else
+#endif /* !MBEDTLS_SSL_NO_SESSION_RESUMPTION */
     {
         /*
          * New session, create a new session id,
@@ -2735,20 +2741,6 @@ static int ssl_write_server_hello( mbedtls_ssl_context *ssl )
                 return( ret );
         }
     }
-    else
-    {
-        /*
-         * Resuming a session
-         */
-        n = ssl->session_negotiate->id_len;
-        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 );
-            return( ret );
-        }
-    }
 
     /*
      *    38  .  38     session id length
@@ -2765,7 +2757,7 @@ static int ssl_write_server_hello( mbedtls_ssl_context *ssl )
     MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, session id len.: %d", n ) );
     MBEDTLS_SSL_DEBUG_BUF( 3,   "server hello, session id", buf + 39, n );
     MBEDTLS_SSL_DEBUG_MSG( 3, ( "%s session has been resumed",
-                   ssl->handshake->resume ? "a" : "no" ) );
+            mbedtls_ssl_handshake_get_resume( ssl->handshake ) ? "a" : "no" ) );
 
     *p++ = (unsigned char)( ssl->session_negotiate->ciphersuite >> 8 );
     *p++ = (unsigned char)( ssl->session_negotiate->ciphersuite      );

library/ssl_tls.c

@@ -1263,11 +1263,13 @@ static int ssl_compute_master( mbedtls_ssl_handshake_params *handshake,
     (void) ssl;
 #endif
 
+#if !defined(MBEDTLS_SSL_NO_SESSION_RESUMPTION)
     if( handshake->resume != 0 )
     {
         MBEDTLS_SSL_DEBUG_MSG( 3, ( "no premaster (session resumed)" ) );
         return( 0 );
     }
+#endif /* !MBEDTLS_SSL_NO_SESSION_RESUMPTION */
 
     MBEDTLS_SSL_DEBUG_BUF( 3, "premaster secret", handshake->premaster,
                                                   handshake->pmslen );
@@ -7285,8 +7287,6 @@ static void ssl_handshake_wrapup_free_hs_transform( mbedtls_ssl_context *ssl )
 
 void mbedtls_ssl_handshake_wrapup( mbedtls_ssl_context *ssl )
 {
-    int resume = ssl->handshake->resume;
-
     MBEDTLS_SSL_DEBUG_MSG( 3, ( "=> handshake wrapup" ) );
 
 #if defined(MBEDTLS_SSL_RENEGOTIATION)
@@ -7314,16 +7314,18 @@ void mbedtls_ssl_handshake_wrapup( mbedtls_ssl_context *ssl )
     ssl->session = ssl->session_negotiate;
     ssl->session_negotiate = NULL;
 
+#if defined(MBEDTLS_SSL_SRV_C) && !defined(MBEDTLS_SSL_NO_SESSION_CACHE)
     /*
      * Add cache entry
      */
     if( ssl->conf->f_set_cache != NULL &&
         ssl->session->id_len != 0 &&
-        resume == 0 )
+        ssl->handshake->resume == 0 )
     {
         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 defined(MBEDTLS_SSL_PROTO_DTLS)
     if( MBEDTLS_SSL_TRANSPORT_IS_DTLS( ssl->conf->transport ) &&
@@ -7372,6 +7374,7 @@ int mbedtls_ssl_write_finished( mbedtls_ssl_context *ssl )
     ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
     ssl->out_msg[0]  = MBEDTLS_SSL_HS_FINISHED;
 
+#if !defined(MBEDTLS_SSL_NO_SESSION_RESUMPTION)
     /*
      * In case of session resuming, invert the client and server
      * ChangeCipherSpec messages order.
@@ -7388,6 +7391,7 @@ int mbedtls_ssl_write_finished( mbedtls_ssl_context *ssl )
 #endif
     }
     else
+#endif /* !MBEDTLS_SSL_NO_SESSION_RESUMPTION */
         ssl->state++;
 
     /*
@@ -7528,6 +7532,7 @@ int mbedtls_ssl_parse_finished( mbedtls_ssl_context *ssl )
     memcpy( ssl->peer_verify_data, buf, hash_len );
 #endif
 
+#if !defined(MBEDTLS_SSL_NO_SESSION_RESUMPTION)
     if( ssl->handshake->resume != 0 )
     {
 #if defined(MBEDTLS_SSL_CLI_C)
@@ -7540,6 +7545,7 @@ int mbedtls_ssl_parse_finished( mbedtls_ssl_context *ssl )
 #endif
     }
     else
+#endif /* !MBEDTLS_SSL_NO_SESSION_RESUMPTION */
         ssl->state++;
 
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
@@ -8164,7 +8170,7 @@ void mbedtls_ssl_set_timer_cb( mbedtls_ssl_context *ssl,
     ssl_set_timer( ssl, 0 );
 }
 
-#if defined(MBEDTLS_SSL_SRV_C)
+#if defined(MBEDTLS_SSL_SRV_C) && !defined(MBEDTLS_SSL_NO_SESSION_CACHE)
 void mbedtls_ssl_conf_session_cache( mbedtls_ssl_config *conf,
         void *p_cache,
         int (*f_get_cache)(void *, mbedtls_ssl_session *),
@@ -8174,9 +8180,9 @@ void mbedtls_ssl_conf_session_cache( mbedtls_ssl_config *conf,
     conf->f_get_cache = f_get_cache;
     conf->f_set_cache = f_set_cache;
 }
-#endif /* MBEDTLS_SSL_SRV_C */
+#endif /* MBEDTLS_SSL_SRV_C && !MBEDTLS_SSL_NO_SESSION_CACHE */
 
-#if defined(MBEDTLS_SSL_CLI_C)
+#if defined(MBEDTLS_SSL_CLI_C) && !defined(MBEDTLS_SSL_NO_SESSION_RESUMPTION)
 int mbedtls_ssl_set_session( mbedtls_ssl_context *ssl, const mbedtls_ssl_session *session )
 {
     int ret;
@@ -8197,7 +8203,7 @@ int mbedtls_ssl_set_session( mbedtls_ssl_context *ssl, const mbedtls_ssl_session
 
     return( 0 );
 }
-#endif /* MBEDTLS_SSL_CLI_C */
+#endif /* MBEDTLS_SSL_CLI_C && !MBEDTLS_SSL_NO_SESSION_RESUMPTION */
 
 void mbedtls_ssl_conf_ciphersuites( mbedtls_ssl_config *conf,
                                    const int *ciphersuites )

library/version_features.c

@@ -513,6 +513,12 @@ static const char *features[] = {
 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
     "MBEDTLS_SSL_SESSION_TICKETS",
 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
+#if defined(MBEDTLS_SSL_NO_SESSION_CACHE)
+    "MBEDTLS_SSL_NO_SESSION_CACHE",
+#endif /* MBEDTLS_SSL_NO_SESSION_CACHE */
+#if defined(MBEDTLS_SSL_NO_SESSION_RESUMPTION)
+    "MBEDTLS_SSL_NO_SESSION_RESUMPTION",
+#endif /* MBEDTLS_SSL_NO_SESSION_RESUMPTION */
 #if defined(MBEDTLS_SSL_EXPORT_KEYS)
     "MBEDTLS_SSL_EXPORT_KEYS",
 #endif /* MBEDTLS_SSL_EXPORT_KEYS */

programs/ssl/dtls_server.c

@@ -236,11 +236,11 @@ int main( void )
     mbedtls_ssl_conf_rng( &conf, mbedtls_ctr_drbg_random, &ctr_drbg );
     mbedtls_ssl_conf_dbg( &conf, my_debug, stdout );
 
-#if defined(MBEDTLS_SSL_CACHE_C)
+#if defined(MBEDTLS_SSL_CACHE_C) && !defined(MBEDTLS_SSL_NO_SESSION_CACHE)
     mbedtls_ssl_conf_session_cache( &conf, &cache,
                                    mbedtls_ssl_cache_get,
                                    mbedtls_ssl_cache_set );
-#endif
+#endif /* MBEDTLS_SSL_CACHE_C && !MBEDTLS_SSL_NO_SESSION_CACHE */
 
     mbedtls_ssl_conf_ca_chain( &conf, srvcert.next, NULL );
    if( ( ret = mbedtls_ssl_conf_own_cert( &conf, &srvcert, &pkey ) ) != 0 )

programs/ssl/query_config.c

@@ -1410,6 +1410,22 @@ int query_config( const char *config )
     }
 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
 
+#if defined(MBEDTLS_SSL_NO_SESSION_CACHE)
+    if( strcmp( "MBEDTLS_SSL_NO_SESSION_CACHE", config ) == 0 )
+    {
+        MACRO_EXPANSION_TO_STR( MBEDTLS_SSL_NO_SESSION_CACHE );
+        return( 0 );
+    }
+#endif /* MBEDTLS_SSL_NO_SESSION_CACHE */
+
+#if defined(MBEDTLS_SSL_NO_SESSION_RESUMPTION)
+    if( strcmp( "MBEDTLS_SSL_NO_SESSION_RESUMPTION", config ) == 0 )
+    {
+        MACRO_EXPANSION_TO_STR( MBEDTLS_SSL_NO_SESSION_RESUMPTION );
+        return( 0 );
+    }
+#endif /* MBEDTLS_SSL_NO_SESSION_RESUMPTION */
+
 #if defined(MBEDTLS_SSL_EXPORT_KEYS)
     if( strcmp( "MBEDTLS_SSL_EXPORT_KEYS", config ) == 0 )
     {

programs/ssl/ssl_client2.c

@@ -2545,12 +2545,14 @@ reconnect:
             }
         }
 
+#if !defined(MBEDTLS_SSL_NO_SESSION_RESUMPTION)
         if( ( ret = mbedtls_ssl_set_session( &ssl, &saved_session ) ) != 0 )
         {
             mbedtls_printf( " failed\n  ! mbedtls_ssl_set_session returned -0x%x\n\n",
                             -ret );
             goto exit;
         }
+#endif /* !MBEDTLS_SSL_NO_SESSION_RESUMPTION */
 
         if( ( ret = mbedtls_net_connect( &server_fd,
                         opt.server_addr, opt.server_port,

programs/ssl/ssl_server.c

@@ -224,11 +224,11 @@ int main( void )
     mbedtls_ssl_conf_rng( &conf, mbedtls_ctr_drbg_random, &ctr_drbg );
     mbedtls_ssl_conf_dbg( &conf, my_debug, stdout );
 
-#if defined(MBEDTLS_SSL_CACHE_C)
+#if defined(MBEDTLS_SSL_CACHE_C) && !defined(MBEDTLS_SSL_NO_SESSION_CACHE)
     mbedtls_ssl_conf_session_cache( &conf, &cache,
                                    mbedtls_ssl_cache_get,
                                    mbedtls_ssl_cache_set );
-#endif
+#endif /* MBEDTLS_SSL_CACHE_C && !MBEDTLS_SSL_NO_SESSION_CACHE */
 
     mbedtls_ssl_conf_ca_chain( &conf, srvcert.next, NULL );
     if( ( ret = mbedtls_ssl_conf_own_cert( &conf, &srvcert, &pkey ) ) != 0 )

programs/ssl/ssl_server2.c

@@ -2542,9 +2542,11 @@ int main( int argc, char *argv[] )
     if( opt.cache_timeout != -1 )
         mbedtls_ssl_cache_set_timeout( &cache, opt.cache_timeout );
 
+#if !defined(MBEDTLS_SSL_NO_SESSION_CACHE)
     mbedtls_ssl_conf_session_cache( &conf, &cache,
                                    mbedtls_ssl_cache_get,
                                    mbedtls_ssl_cache_set );
+#endif /* !MBEDTLS_SSL_NO_SESSION_CACHE */
 #endif
 
 #if defined(MBEDTLS_SSL_SESSION_TICKETS)

scripts/config.pl

@@ -32,6 +32,8 @@
 #   MBEDTLS_REMOVE_3DES_CIPHERSUITES
 #   MBEDTLS_SSL_HW_RECORD_ACCEL
 #   MBEDTLS_SSL_PROTO_NO_DTLS
+#   MBEDTLS_SSL_NO_SESSION_CACHE
+#   MBEDTLS_SSL_NO_SESSION_RESUMPTION
 #   MBEDTLS_RSA_NO_CRT
 #   MBEDTLS_X509_ALLOW_EXTENSIONS_NON_V3
 #   MBEDTLS_X509_ALLOW_UNSUPPORTED_CRITICAL_EXTENSION
@@ -95,6 +97,8 @@ MBEDTLS_REMOVE_ARC4_CIPHERSUITES
 MBEDTLS_REMOVE_3DES_CIPHERSUITES
 MBEDTLS_SSL_HW_RECORD_ACCEL
 MBEDTLS_SSL_PROTO_NO_TLS
+MBEDTLS_SSL_NO_SESSION_CACHE
+MBEDTLS_SSL_NO_SESSION_RESUMPTION
 MBEDTLS_X509_ALLOW_EXTENSIONS_NON_V3
 MBEDTLS_X509_ALLOW_UNSUPPORTED_CRITICAL_EXTENSION
 MBEDTLS_X509_REMOVE_INFO

tests/scripts/all.sh

@@ -682,6 +682,21 @@ component_test_rsa_no_crt () {
     if_build_succeeded tests/compat.sh -t RSA
 }
 
+component_test_no_resumption () {
+    msg "build: Default + MBEDTLS_SSL_NO_SESSION_RESUMPTION (ASan build)" # ~ 6 min
+    scripts/config.pl unset MBEDTLS_SSL_SESSION_TICKETS
+    scripts/config.pl set MBEDTLS_SSL_NO_SESSION_CACHE
+    scripts/config.pl set MBEDTLS_SSL_NO_SESSION_RESUMPTION
+    CC=gcc cmake -D CMAKE_BUILD_TYPE:String=Asan .
+    make
+
+    msg "test: MBEDTLS_SSL_NO_SESSION_RESUMPTION - main suites (inc. selftests) (ASan build)" # ~ 50s
+    make test
+
+    msg "test: MBEDTLS_SSL_NO_SESSION_RESUMPTION - ssl-opt.sh (ASan build)" # ~ 6 min
+    if_build_succeeded tests/ssl-opt.sh
+}
+
 component_test_small_ssl_out_content_len () {
     msg "build: small SSL_OUT_CONTENT_LEN (ASan build)"
     scripts/config.pl set MBEDTLS_SSL_IN_CONTENT_LEN 16384

tests/ssl-opt.sh

@@ -2130,6 +2130,9 @@ run_test    "Fallback SCSV: end of list" \
             -s "inapropriate fallback"
 
 ## Here the expected response is a valid ServerHello prefix, up to the random.
+## Due to the way the clienthello was generated, this currently needs the
+## server to have support for session tickets.
+requires_config_enabled MBEDTLS_SSL_SESSION_TICKETS
 requires_openssl_with_fallback_scsv
 run_test    "Fallback SCSV: not in list" \
             "$P_SRV debug_level=2" \
@@ -2206,6 +2209,8 @@ run_test    "CBC Record splitting: TLS 1.0, splitting, nbio" \
 
 # Tests for Session Tickets
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_enabled MBEDTLS_SSL_SESSION_TICKETS
 run_test    "Session resume using tickets: basic" \
             "$P_SRV debug_level=3 tickets=1" \
             "$P_CLI debug_level=3 tickets=1 reconnect=1" \
@@ -2220,6 +2225,8 @@ run_test    "Session resume using tickets: basic" \
             -s "a session has been resumed" \
             -c "a session has been resumed"
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_enabled MBEDTLS_SSL_SESSION_TICKETS
 run_test    "Session resume using tickets: cache disabled" \
             "$P_SRV debug_level=3 tickets=1 cache_max=0" \
             "$P_CLI debug_level=3 tickets=1 reconnect=1" \
@@ -2234,6 +2241,8 @@ run_test    "Session resume using tickets: cache disabled" \
             -s "a session has been resumed" \
             -c "a session has been resumed"
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_enabled MBEDTLS_SSL_SESSION_TICKETS
 run_test    "Session resume using tickets: timeout" \
             "$P_SRV debug_level=3 tickets=1 cache_max=0 ticket_timeout=1" \
             "$P_CLI debug_level=3 tickets=1 reconnect=1 reco_delay=2" \
@@ -2248,6 +2257,8 @@ run_test    "Session resume using tickets: timeout" \
             -S "a session has been resumed" \
             -C "a session has been resumed"
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_enabled MBEDTLS_SSL_SESSION_TICKETS
 run_test    "Session resume using tickets: session copy" \
             "$P_SRV debug_level=3 tickets=1 cache_max=0" \
             "$P_CLI debug_level=3 tickets=1 reconnect=1 reco_mode=0" \
@@ -2262,6 +2273,8 @@ run_test    "Session resume using tickets: session copy" \
             -s "a session has been resumed" \
             -c "a session has been resumed"
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_enabled MBEDTLS_SSL_SESSION_TICKETS
 run_test    "Session resume using tickets: openssl server" \
             "$O_SRV" \
             "$P_CLI debug_level=3 tickets=1 reconnect=1" \
@@ -2271,6 +2284,8 @@ run_test    "Session resume using tickets: openssl server" \
             -c "parse new session ticket" \
             -c "a session has been resumed"
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_enabled MBEDTLS_SSL_SESSION_TICKETS
 run_test    "Session resume using tickets: openssl client" \
             "$P_SRV debug_level=3 tickets=1" \
             "( $O_CLI -sess_out $SESSION; \
@@ -2285,6 +2300,8 @@ run_test    "Session resume using tickets: openssl client" \
 
 # Tests for Session Tickets with DTLS
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_enabled MBEDTLS_SSL_SESSION_TICKETS
 run_test    "Session resume using tickets, DTLS: basic" \
             "$P_SRV debug_level=3 dtls=1 tickets=1" \
             "$P_CLI debug_level=3 dtls=1 tickets=1 reconnect=1" \
@@ -2299,6 +2316,8 @@ run_test    "Session resume using tickets, DTLS: basic" \
             -s "a session has been resumed" \
             -c "a session has been resumed"
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_enabled MBEDTLS_SSL_SESSION_TICKETS
 run_test    "Session resume using tickets, DTLS: cache disabled" \
             "$P_SRV debug_level=3 dtls=1 tickets=1 cache_max=0" \
             "$P_CLI debug_level=3 dtls=1 tickets=1 reconnect=1" \
@@ -2313,6 +2332,8 @@ run_test    "Session resume using tickets, DTLS: cache disabled" \
             -s "a session has been resumed" \
             -c "a session has been resumed"
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_enabled MBEDTLS_SSL_SESSION_TICKETS
 run_test    "Session resume using tickets, DTLS: timeout" \
             "$P_SRV debug_level=3 dtls=1 tickets=1 cache_max=0 ticket_timeout=1" \
             "$P_CLI debug_level=3 dtls=1 tickets=1 reconnect=1 reco_delay=2" \
@@ -2327,6 +2348,8 @@ run_test    "Session resume using tickets, DTLS: timeout" \
             -S "a session has been resumed" \
             -C "a session has been resumed"
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_enabled MBEDTLS_SSL_SESSION_TICKETS
 run_test    "Session resume using tickets, DTLS: session copy" \
             "$P_SRV debug_level=3 dtls=1 tickets=1 cache_max=0" \
             "$P_CLI debug_level=3 dtls=1 tickets=1 reconnect=1 reco_mode=0" \
@@ -2341,6 +2364,8 @@ run_test    "Session resume using tickets, DTLS: session copy" \
             -s "a session has been resumed" \
             -c "a session has been resumed"
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_enabled MBEDTLS_SSL_SESSION_TICKETS
 run_test    "Session resume using tickets, DTLS: openssl server" \
             "$O_SRV -dtls1" \
             "$P_CLI dtls=1 debug_level=3 tickets=1 reconnect=1" \
@@ -2350,6 +2375,8 @@ run_test    "Session resume using tickets, DTLS: openssl server" \
             -c "parse new session ticket" \
             -c "a session has been resumed"
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_enabled MBEDTLS_SSL_SESSION_TICKETS
 run_test    "Session resume using tickets, DTLS: openssl client" \
             "$P_SRV dtls=1 debug_level=3 tickets=1" \
             "( $O_CLI -dtls1 -sess_out $SESSION; \
@@ -2364,6 +2391,9 @@ run_test    "Session resume using tickets, DTLS: openssl client" \
 
 # Tests for Session Resume based on session-ID and cache
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_enabled MBEDTLS_SSL_SESSION_TICKETS
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_CACHE
 run_test    "Session resume using cache: tickets enabled on client" \
             "$P_SRV debug_level=3 tickets=0" \
             "$P_CLI debug_level=3 tickets=1 reconnect=1" \
@@ -2378,6 +2408,9 @@ run_test    "Session resume using cache: tickets enabled on client" \
             -s "a session has been resumed" \
             -c "a session has been resumed"
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_enabled MBEDTLS_SSL_SESSION_TICKETS
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_CACHE
 run_test    "Session resume using cache: tickets enabled on server" \
             "$P_SRV debug_level=3 tickets=1" \
             "$P_CLI debug_level=3 tickets=0 reconnect=1" \
@@ -2392,6 +2425,8 @@ run_test    "Session resume using cache: tickets enabled on server" \
             -s "a session has been resumed" \
             -c "a session has been resumed"
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_CACHE
 run_test    "Session resume using cache: cache_max=0" \
             "$P_SRV debug_level=3 tickets=0 cache_max=0" \
             "$P_CLI debug_level=3 tickets=0 reconnect=1" \
@@ -2401,6 +2436,8 @@ run_test    "Session resume using cache: cache_max=0" \
             -S "a session has been resumed" \
             -C "a session has been resumed"
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_CACHE
 run_test    "Session resume using cache: cache_max=1" \
             "$P_SRV debug_level=3 tickets=0 cache_max=1" \
             "$P_CLI debug_level=3 tickets=0 reconnect=1" \
@@ -2410,6 +2447,8 @@ run_test    "Session resume using cache: cache_max=1" \
             -s "a session has been resumed" \
             -c "a session has been resumed"
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_CACHE
 run_test    "Session resume using cache: timeout > delay" \
             "$P_SRV debug_level=3 tickets=0" \
             "$P_CLI debug_level=3 tickets=0 reconnect=1 reco_delay=0" \
@@ -2419,6 +2458,8 @@ run_test    "Session resume using cache: timeout > delay" \
             -s "a session has been resumed" \
             -c "a session has been resumed"
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_CACHE
 run_test    "Session resume using cache: timeout < delay" \
             "$P_SRV debug_level=3 tickets=0 cache_timeout=1" \
             "$P_CLI debug_level=3 tickets=0 reconnect=1 reco_delay=2" \
@@ -2428,6 +2469,8 @@ run_test    "Session resume using cache: timeout < delay" \
             -S "a session has been resumed" \
             -C "a session has been resumed"
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_CACHE
 run_test    "Session resume using cache: no timeout" \
             "$P_SRV debug_level=3 tickets=0 cache_timeout=0" \
             "$P_CLI debug_level=3 tickets=0 reconnect=1 reco_delay=2" \
@@ -2437,6 +2480,8 @@ run_test    "Session resume using cache: no timeout" \
             -s "a session has been resumed" \
             -c "a session has been resumed"
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_CACHE
 run_test    "Session resume using cache: session copy" \
             "$P_SRV debug_level=3 tickets=0" \
             "$P_CLI debug_level=3 tickets=0 reconnect=1 reco_mode=0" \
@@ -2446,6 +2491,8 @@ run_test    "Session resume using cache: session copy" \
             -s "a session has been resumed" \
             -c "a session has been resumed"
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_CACHE
 run_test    "Session resume using cache: openssl client" \
             "$P_SRV debug_level=3 tickets=0" \
             "( $O_CLI -sess_out $SESSION; \
@@ -2458,6 +2505,8 @@ run_test    "Session resume using cache: openssl client" \
             -S "session successfully restored from ticket" \
             -s "a session has been resumed"
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_CACHE
 run_test    "Session resume using cache: openssl server" \
             "$O_SRV" \
             "$P_CLI debug_level=3 tickets=0 reconnect=1" \
@@ -2468,6 +2517,9 @@ run_test    "Session resume using cache: openssl server" \
 
 # Tests for Session Resume based on session-ID and cache, DTLS
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_enabled MBEDTLS_SSL_SESSION_TICKETS
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_CACHE
 run_test    "Session resume using cache, DTLS: tickets enabled on client" \
             "$P_SRV dtls=1 debug_level=3 tickets=0" \
             "$P_CLI dtls=1 debug_level=3 tickets=1 reconnect=1" \
@@ -2482,6 +2534,9 @@ run_test    "Session resume using cache, DTLS: tickets enabled on client" \
             -s "a session has been resumed" \
             -c "a session has been resumed"
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_enabled MBEDTLS_SSL_SESSION_TICKETS
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_CACHE
 run_test    "Session resume using cache, DTLS: tickets enabled on server" \
             "$P_SRV dtls=1 debug_level=3 tickets=1" \
             "$P_CLI dtls=1 debug_level=3 tickets=0 reconnect=1" \
@@ -2496,6 +2551,8 @@ run_test    "Session resume using cache, DTLS: tickets enabled on server" \
             -s "a session has been resumed" \
             -c "a session has been resumed"
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_CACHE
 run_test    "Session resume using cache, DTLS: cache_max=0" \
             "$P_SRV dtls=1 debug_level=3 tickets=0 cache_max=0" \
             "$P_CLI dtls=1 debug_level=3 tickets=0 reconnect=1" \
@@ -2505,6 +2562,8 @@ run_test    "Session resume using cache, DTLS: cache_max=0" \
             -S "a session has been resumed" \
             -C "a session has been resumed"
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_CACHE
 run_test    "Session resume using cache, DTLS: cache_max=1" \
             "$P_SRV dtls=1 debug_level=3 tickets=0 cache_max=1" \
             "$P_CLI dtls=1 debug_level=3 tickets=0 reconnect=1" \
@@ -2514,6 +2573,8 @@ run_test    "Session resume using cache, DTLS: cache_max=1" \
             -s "a session has been resumed" \
             -c "a session has been resumed"
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_CACHE
 run_test    "Session resume using cache, DTLS: timeout > delay" \
             "$P_SRV dtls=1 debug_level=3 tickets=0" \
             "$P_CLI dtls=1 debug_level=3 tickets=0 reconnect=1 reco_delay=0" \
@@ -2523,6 +2584,8 @@ run_test    "Session resume using cache, DTLS: timeout > delay" \
             -s "a session has been resumed" \
             -c "a session has been resumed"
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_CACHE
 run_test    "Session resume using cache, DTLS: timeout < delay" \
             "$P_SRV dtls=1 debug_level=3 tickets=0 cache_timeout=1" \
             "$P_CLI dtls=1 debug_level=3 tickets=0 reconnect=1 reco_delay=2" \
@@ -2532,6 +2595,8 @@ run_test    "Session resume using cache, DTLS: timeout < delay" \
             -S "a session has been resumed" \
             -C "a session has been resumed"
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_CACHE
 run_test    "Session resume using cache, DTLS: no timeout" \
             "$P_SRV dtls=1 debug_level=3 tickets=0 cache_timeout=0" \
             "$P_CLI dtls=1 debug_level=3 tickets=0 reconnect=1 reco_delay=2" \
@@ -2541,6 +2606,8 @@ run_test    "Session resume using cache, DTLS: no timeout" \
             -s "a session has been resumed" \
             -c "a session has been resumed"
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_CACHE
 run_test    "Session resume using cache, DTLS: session copy" \
             "$P_SRV dtls=1 debug_level=3 tickets=0" \
             "$P_CLI dtls=1 debug_level=3 tickets=0 reconnect=1 reco_mode=0" \
@@ -2550,6 +2617,8 @@ run_test    "Session resume using cache, DTLS: session copy" \
             -s "a session has been resumed" \
             -c "a session has been resumed"
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_CACHE
 run_test    "Session resume using cache, DTLS: openssl client" \
             "$P_SRV dtls=1 debug_level=3 tickets=0" \
             "( $O_CLI -dtls1 -sess_out $SESSION; \
@@ -2562,6 +2631,8 @@ run_test    "Session resume using cache, DTLS: openssl client" \
             -S "session successfully restored from ticket" \
             -s "a session has been resumed"
 
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_CACHE
 run_test    "Session resume using cache, DTLS: openssl server" \
             "$O_SRV -dtls1" \
             "$P_CLI dtls=1 debug_level=3 tickets=0 reconnect=1" \
@@ -7864,6 +7935,8 @@ run_test    "DTLS reordering: Buffer out-of-order handshake message on server" \
             -S "Injecting buffered CCS message" \
             -S "Remember CCS message"
 
+# This needs session tickets; otherwise CCS is the first message in its flight
+requires_config_enabled MBEDTLS_SSL_SESSION_TICKETS
 run_test    "DTLS reordering: Buffer out-of-order CCS message on client"\
             -p "$P_PXY delay_srv=NewSessionTicket" \
             "$P_SRV dgram_packing=0 cookies=0 dtls=1 debug_level=2 \
@@ -8006,6 +8079,9 @@ run_test    "DTLS proxy: 3d, max handshake, nbio" \
             -c "HTTP/1.0 200 OK"
 
 client_needs_more_time 4
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_enabled MBEDTLS_SSL_SESSION_TICKETS
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_CACHE
 run_test    "DTLS proxy: 3d, min handshake, resumption" \
             -p "$P_PXY drop=5 delay=5 duplicate=5" \
             "$P_SRV dtls=1 dgram_packing=0 hs_timeout=500-10000 tickets=0 auth_mode=none \
@@ -8020,6 +8096,9 @@ run_test    "DTLS proxy: 3d, min handshake, resumption" \
             -c "HTTP/1.0 200 OK"
 
 client_needs_more_time 4
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_RESUMPTION
+requires_config_enabled MBEDTLS_SSL_SESSION_TICKETS
+requires_config_disabled MBEDTLS_SSL_NO_SESSION_CACHE
 run_test    "DTLS proxy: 3d, min handshake, resumption, nbio" \
             -p "$P_PXY drop=5 delay=5 duplicate=5" \
             "$P_SRV dtls=1 dgram_packing=0 hs_timeout=500-10000 tickets=0 auth_mode=none \