- unsigned int *id_len)
- {
- unsigned int count = 0;
- do {
- RAND_pseudo_bytes(id, *id_len);
- /* Prefix the session_id with the required prefix. NB: If our
- * prefix is too long, clip it - but there will be worse effects
- * anyway, eg. the server could only possibly create 1 session
- * ID (ie. the prefix!) so all future session negotiations will
- * fail due to conflicts. */
- memcpy(id, session_id_prefix,
- (strlen(session_id_prefix) < *id_len) ?
- strlen(session_id_prefix) : *id_len);
- }
- while(SSL_has_matching_session_id(ssl, id, *id_len) &&
- (++count < MAX_SESSION_ID_ATTEMPTS));
- if(count >= MAX_SESSION_ID_ATTEMPTS)
- return 0;
- return 1;
- }
+ unsigned int *id_len)
+{
+ unsigned int count = 0;
+ do {
+ RAND_pseudo_bytes(id, *id_len);
+ /*
+ * Prefix the session_id with the required prefix. NB: If our prefix
+ * is too long, clip it - but there will be worse effects anyway, eg.
+ * the server could only possibly create 1 session ID (ie. the
+ * prefix!) so all future session negotiations will fail due to
+ * conflicts.
+ */
+ memcpy(id, session_id_prefix,
+ (strlen(session_id_prefix) < *id_len) ?
+ strlen(session_id_prefix) : *id_len);
+ }
+ while (SSL_has_matching_session_id(ssl, id, *id_len) &&
+ (++count < MAX_SESSION_ID_ATTEMPTS));
+ if (count >= MAX_SESSION_ID_ATTEMPTS)
+ return 0;
+ return 1;
+}
+
+/*
+ * By default s_server uses an in-memory cache which caches SSL_SESSION
+ * structures without any serialisation. This hides some bugs which only
+ * become apparent in deployed servers. By implementing a basic external
+ * session cache some issues can be debugged using s_server.
+ */
+
+typedef struct simple_ssl_session_st {
+ unsigned char *id;
+ unsigned int idlen;
+ unsigned char *der;
+ int derlen;
+ struct simple_ssl_session_st *next;
+} simple_ssl_session;
+
+static simple_ssl_session *first = NULL;
+
+static int add_session(SSL *ssl, SSL_SESSION *session)
+{
+ simple_ssl_session *sess;
+ unsigned char *p;
+
+ sess = OPENSSL_malloc(sizeof(simple_ssl_session));
+ if(!sess) {
+ BIO_printf(bio_err, "Out of memory adding session to external cache\n");
+ return 0;
+ }
+
+ SSL_SESSION_get_id(session, &sess->idlen);
+ sess->derlen = i2d_SSL_SESSION(session, NULL);
+
+ sess->id = BUF_memdup(SSL_SESSION_get_id(session, NULL), sess->idlen);
+
+ sess->der = OPENSSL_malloc(sess->derlen);
+ if(!sess->id || !sess->der) {
+ BIO_printf(bio_err, "Out of memory adding session to external cache\n");
+
+ if(sess->id)
+ OPENSSL_free(sess->id);
+ if(sess->der)
+ OPENSSL_free(sess->der);
+ OPENSSL_free(sess);
+ return 0;
+ }
+ p = sess->der;
+ i2d_SSL_SESSION(session, &p);
+
+ sess->next = first;
+ first = sess;
+ BIO_printf(bio_err, "New session added to external cache\n");
+ return 0;
+}
+
+static SSL_SESSION *get_session(SSL *ssl, unsigned char *id, int idlen,
+ int *do_copy)
+{
+ simple_ssl_session *sess;
+ *do_copy = 0;
+ for (sess = first; sess; sess = sess->next) {
+ if (idlen == (int)sess->idlen && !memcmp(sess->id, id, idlen)) {
+ const unsigned char *p = sess->der;
+ BIO_printf(bio_err, "Lookup session: cache hit\n");
+ return d2i_SSL_SESSION(NULL, &p, sess->derlen);
+ }
+ }
+ BIO_printf(bio_err, "Lookup session: cache miss\n");
+ return NULL;
+}
+
+static void del_session(SSL_CTX *sctx, SSL_SESSION *session)
+{
+ simple_ssl_session *sess, *prev = NULL;
+ const unsigned char *id;
+ unsigned int idlen;
+ id = SSL_SESSION_get_id(session, &idlen);
+ for (sess = first; sess; sess = sess->next) {
+ if (idlen == sess->idlen && !memcmp(sess->id, id, idlen)) {
+ if (prev)
+ prev->next = sess->next;
+ else
+ first = sess->next;
+ OPENSSL_free(sess->id);
+ OPENSSL_free(sess->der);
+ OPENSSL_free(sess);
+ return;
+ }
+ prev = sess;
+ }
+}
+
+static void init_session_cache_ctx(SSL_CTX *sctx)
+{
+ SSL_CTX_set_session_cache_mode(sctx,
+ SSL_SESS_CACHE_NO_INTERNAL |
+ SSL_SESS_CACHE_SERVER);
+ SSL_CTX_sess_set_new_cb(sctx, add_session);
+ SSL_CTX_sess_set_get_cb(sctx, get_session);
+ SSL_CTX_sess_set_remove_cb(sctx, del_session);
+}
+
+static void free_sessions(void)
+{
+ simple_ssl_session *sess, *tsess;
+ for (sess = first; sess;) {
+ OPENSSL_free(sess->id);
+ OPENSSL_free(sess->der);
+ tsess = sess;
+ sess = sess->next;
+ OPENSSL_free(tsess);
+ }
+ first = NULL;
+}