Fix CVE-2024-2511

CHANGES

@@ -4,6 +4,8 @@
 
  Changes between 8.4.0 and 8.5.0 [xx XXX xxxx]
 
+  *) 修复CVE-2024-2511
+
   *) 修复CVE-2023-6129
 
   *) 修复CVE-2023-6237

ssl/ssl_lib.c

@@ -3840,9 +3840,10 @@ void ssl_update_cache(SSL *s, int mode)
 
     /*
      * If the session_id_length is 0, we are not supposed to cache it, and it
-     * would be rather hard to do anyway :-)
+     * would be rather hard to do anyway :-). Also if the session has already
+     * been marked as not_resumable we should not cache it for later reuse.
      */
-    if (s->session->session_id_length == 0)
+    if (s->session->session_id_length == 0 || s->session->not_resumable)
         return;
 
     /*

ssl/ssl_sess.c

@@ -157,16 +157,11 @@ SSL_SESSION *SSL_SESSION_new(void)
     return ss;
 }
 
-SSL_SESSION *SSL_SESSION_dup(const SSL_SESSION *src)
-{
-    return ssl_session_dup(src, 1);
-}
-
 /*
  * Create a new SSL_SESSION and duplicate the contents of |src| into it. If
  * ticket == 0 then no ticket information is duplicated, otherwise it is.
  */
-SSL_SESSION *ssl_session_dup(const SSL_SESSION *src, int ticket)
+static SSL_SESSION *ssl_session_dup_intern(const SSL_SESSION *src, int ticket)
 {
     SSL_SESSION *dest;
 
@@ -310,6 +305,27 @@ SSL_SESSION *ssl_session_dup(const SSL_SESSION *src, int ticket)
     return NULL;
 }
 
+SSL_SESSION *SSL_SESSION_dup(const SSL_SESSION *src)
+{
+    return ssl_session_dup_intern(src, 1);
+}
+
+/*
+ * Used internally when duplicating a session which might be already shared.
+ * We will have resumed the original session. Subsequently we might have marked
+ * it as non-resumable (e.g. in another thread) - but this copy should be ok to
+ * resume from.
+ */
+SSL_SESSION *ssl_session_dup(const SSL_SESSION *src, int ticket)
+{
+    SSL_SESSION *sess = ssl_session_dup_intern(src, ticket);
+
+    if (sess != NULL)
+        sess->not_resumable = 0;
+
+    return sess;
+}
+
 const unsigned char *SSL_SESSION_get_id(const SSL_SESSION *s, unsigned int *len)
 {
     if (len)
@@ -563,6 +579,12 @@ SSL_SESSION *lookup_sess_in_cache(SSL *s, const unsigned char *sess_id,
 #endif
 
         if (ret != NULL) {
+            if (ret->not_resumable) {
+                /* If its not resumable then ignore this session */
+                if (!copy)
+                    SSL_SESSION_free(ret);
+                return NULL;
+            }
             ssl_tsan_counter(s->session_ctx,
                              &s->session_ctx->stats.sess_cb_hit);
 
@@ -824,32 +846,36 @@ int SSL_CTX_add_session(SSL_CTX *ctx, SSL_SESSION *c)
         c->time = time(NULL);
         ssl_session_calculate_timeout(c);
     }
-    SSL_SESSION_list_add(ctx, c);
 
-    if (s != NULL) {
-        /*
-         * existing cache entry -- decrement previously incremented reference
-         * count because it already takes into account the cache
-         */
-
-        SSL_SESSION_free(s);    /* s == c */
-        ret = 0;
-    } else {
+    if (s == NULL) {
         /*
          * new cache entry -- remove old ones if cache has become too large
+         * delete cache entry *before* add, so we don't remove the one we're adding!
          */
 
         ret = 1;
 
         if (SSL_CTX_sess_get_cache_size(ctx) > 0) {
-            while (SSL_CTX_sess_number(ctx) > SSL_CTX_sess_get_cache_size(ctx)) {
+            while (SSL_CTX_sess_number(ctx) >= SSL_CTX_sess_get_cache_size(ctx)) {
                 if (!remove_session_lock(ctx, ctx->session_cache_tail, 0))
                     break;
                 else
                     ssl_tsan_counter(ctx, &ctx->stats.sess_cache_full);
             }
         }
     }
+
+    SSL_SESSION_list_add(ctx, c);
+
+    if (s != NULL) {
+        /*
+         * existing cache entry -- decrement previously incremented reference
+         * count because it already takes into account the cache
+         */
+
+        SSL_SESSION_free(s);    /* s == c */
+        ret = 0;
+    }
     CRYPTO_THREAD_unlock(ctx->lock);
     return ret;
 }

ssl/statem/statem_srvr.c

@@ -2522,9 +2522,8 @@ int tls_construct_server_hello(SSL *s, WPACKET *pkt)
      * so the following won't overwrite an ID that we're supposed
      * to send back.
      */
-    if (s->session->not_resumable ||
-        (!(s->ctx->session_cache_mode & SSL_SESS_CACHE_SERVER)
-         && !s->hit))
+    if (!(s->ctx->session_cache_mode & SSL_SESS_CACHE_SERVER)
+            && !s->hit)
         s->session->session_id_length = 0;
 
     if (usetls13) {