Duplicate SSL_SESSIONs when renewing them.
See also upstream's 27c76b9b8010b536687318739c6f631ce4194688, CVE-2015-1791.
Rather than write a dup function, serializing and deserializing the object is
simpler. It also fixes a bug in the original fix where it never calls
new_session_cb to store the new session (for clients which use that callback;
how clients should handle the session cache is much less clear).
The old session isn't pruned as we haven't processed the Finished message yet.
RFC 5077 says:
The server MUST NOT assume that the client actually received the updated
ticket until it successfully verifies the client's Finished message.
Moreover, because network messages are asynchronous, a new SSL connection may
have began just before the client received the new ticket, so any such servers
are broken regardless.
Change-Id: I13b3dc986dc58ea2ce66659dbb29e14cd02a641b
Reviewed-on: https://boringssl-review.googlesource.com/5122
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c
index e82447c..1328cd5 100644
--- a/ssl/ssl_lib.c
+++ b/ssl/ssl_lib.c
@@ -1948,8 +1948,16 @@
return;
}
+ int has_new_session = !s->hit;
+ if (!s->server && s->tlsext_ticket_expected) {
+ /* A client may see new sessions on abbreviated handshakes if the server
+ * decides to renew the ticket. Once the handshake is completed, it should
+ * be inserted into the cache. */
+ has_new_session = 1;
+ }
+
SSL_CTX *ctx = s->initial_ctx;
- if ((ctx->session_cache_mode & mode) == mode && !s->hit &&
+ if ((ctx->session_cache_mode & mode) == mode && has_new_session &&
((ctx->session_cache_mode & SSL_SESS_CACHE_NO_INTERNAL_STORE) ||
SSL_CTX_add_session(ctx, s->session)) &&
ctx->new_session_cb != NULL) {