session tickets: check timestamp for validity

We were previously only relying on the client's view of the
ticket lifetime for TLS1.3 tickets. This makes sure that we
only resume tickets that the server considers valid and consolidates
the expiration time checks to _gnutls_check_resumed_params().

Signed-off-by: Nikos Mavrogiannopoulos <nmav@redhat.com>

diff --git a/lib/db.c b/lib/db.c
index 38225d31f5012761e6b576ec815d1acae0aff059..a029f351cd39b04e3f9b07231d5f4fc5f3a1eb2e 100644 (file)
--- a/lib/db.c
+++ b/lib/db.c
@@ -260,12 +260,28 @@ int _gnutls_server_register_current_session(gnutls_session_t session)
 
 int _gnutls_check_resumed_params(gnutls_session_t session)
 {
-       if (session->internals.resumed_security_parameters.ext_master_secret != 
-           session->security_parameters.ext_master_secret)
-           return gnutls_assert_val(GNUTLS_E_INVALID_SESSION);
-
-       if (!_gnutls_server_name_matches_resumed(session))
-           return gnutls_assert_val(GNUTLS_E_INVALID_SESSION);
+       time_t timestamp = gnutls_time(0);
+       const version_entry_st *vers;
+
+       /* check whether the session is expired */
+       if (timestamp -
+           session->internals.resumed_security_parameters.timestamp >
+           session->internals.expire_time
+           || session->internals.resumed_security_parameters.timestamp >
+           timestamp)
+               return gnutls_assert_val(GNUTLS_E_EXPIRED);
+
+       /* check various parameters applicable to resumption in TLS1.2 or earlier
+        */
+       vers = get_version(session);
+       if (!vers || !vers->tls13_sem) {
+               if (session->internals.resumed_security_parameters.ext_master_secret !=
+                   session->security_parameters.ext_master_secret)
+                       return gnutls_assert_val(GNUTLS_E_INVALID_SESSION);
+
+               if (!_gnutls_server_name_matches_resumed(session))
+                       return gnutls_assert_val(GNUTLS_E_INVALID_SESSION);
+       }
 
        return 0;
 }
@@ -311,7 +327,6 @@ _gnutls_server_restore_session(gnutls_session_t session,
                return GNUTLS_E_INVALID_SESSION;
        }
 
-       /* expiration check is performed inside */
        ret = gnutls_session_set_data(session, data.data, data.size);
        gnutls_free(data.data);
 
@@ -320,6 +335,7 @@ _gnutls_server_restore_session(gnutls_session_t session,
                return ret;
        }
 
+       /* expiration check is performed inside */
        ret = _gnutls_check_resumed_params(session);
        if (ret < 0)
                return gnutls_assert_val(ret);

diff --git a/lib/ext/session_ticket.c b/lib/ext/session_ticket.c
index 177135e6420b5310bd036859eb602e2230dbf954..3eb63818b90fbcf7a7559553fe1028be54055207 100644 (file)
--- a/lib/ext/session_ticket.c
+++ b/lib/ext/session_ticket.c
@@ -349,7 +349,6 @@ static int
 unpack_session(gnutls_session_t session, const gnutls_datum_t *state)
 {
        int ret;
-       time_t timestamp = gnutls_time(0);
 
        if (unlikely(!state))
                return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
@@ -358,13 +357,6 @@ unpack_session(gnutls_session_t session, const gnutls_datum_t *state)
        if (ret < 0)
                return gnutls_assert_val(ret);
 
-       if (timestamp -
-           session->internals.resumed_security_parameters.timestamp >
-           session->internals.expire_time
-           || session->internals.resumed_security_parameters.timestamp >
-           timestamp)
-               return gnutls_assert_val(GNUTLS_E_EXPIRED);
-
        ret = _gnutls_check_resumed_params(session);
        if (ret < 0)
                return gnutls_assert_val(ret);

diff --git a/lib/session_pack.c b/lib/session_pack.c
index f8b1830568ca83f2721c13f7d10d8d634aa228ba..c5801fb32ef53ced9c109e19c6c2c7d111e8aa8b 100644 (file)
--- a/lib/session_pack.c
+++ b/lib/session_pack.c
@@ -960,8 +960,6 @@ unpack_security_parameters(gnutls_session_t session, gnutls_buffer_st * ps)
        session->internals.resumed_security_parameters.timestamp =
            timestamp;
 
-       timestamp = gnutls_time(0);
-
        BUFFER_POP_NUM(ps,
                       session->internals.resumed_security_parameters.
                       entity);
@@ -1071,15 +1069,6 @@ unpack_security_parameters(gnutls_session_t session, gnutls_buffer_st * ps)
                }
        }
 
-       if (timestamp -
-           session->internals.resumed_security_parameters.timestamp >
-           session->internals.expire_time
-           || session->internals.resumed_security_parameters.timestamp >
-           timestamp) {
-               gnutls_assert();
-               return GNUTLS_E_EXPIRED;
-       }
-
        ret = 0;
 
       error:

diff --git a/lib/tls13/session_ticket.c b/lib/tls13/session_ticket.c
index 8087ba7a8b9068f631ae8d8bf576b934744bbeb4..36d5dc526010992fab8a1384e8f78c53421305ae 100644 (file)
--- a/lib/tls13/session_ticket.c
+++ b/lib/tls13/session_ticket.c
@@ -31,6 +31,7 @@
 #include "auth/cert.h"
 #include "tls13/session_ticket.h"
 #include "session_pack.h"
+#include "db.h"
 
 static int
 pack_ticket(gnutls_session_t session, tls13_ticket_t *ticket, gnutls_datum_t *packed)
@@ -422,9 +423,12 @@ int _gnutls13_unpack_session_ticket(gnutls_session_t session,
        /* Return ticket parameters */
        ret = unpack_ticket(session, &decrypted, ticket_data);
        _gnutls_free_datum(&decrypted);
-       if (ret < 0) {
+       if (ret < 0)
                return ret;
-       }
+
+       ret = _gnutls_check_resumed_params(session);
+       if (ret < 0)
+               return gnutls_assert_val(ret);
 
        return 0;
 }