diff options
author | Daiki Ueno <ueno@gnu.org> | 2020-08-22 17:19:39 +0200 |
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committer | Daiki Ueno <ueno@gnu.org> | 2020-09-03 16:41:26 +0200 |
commit | 29ee67c205855e848a0a26e6d0e4f65b6b943e0a (patch) | |
tree | cec3c0f89def18e8448c42faff1b4036ea2c75ff /lib/handshake.c | |
parent | f9e56c3a51f4ba8b91cead5526ff14ec75d2a35d (diff) | |
download | gnutls-29ee67c205855e848a0a26e6d0e4f65b6b943e0a.tar.gz |
handshake: reject no_renegotiation alert if handshake is incompletetmp-renegotiation
If the initial handshake is incomplete and the server sends a
no_renegotiation alert, the client should treat it as a fatal error
even if its level is warning. Otherwise the same handshake
state (e.g., DHE parameters) are reused in the next gnutls_handshake
call, if it is called in the loop idiom:
do {
ret = gnutls_handshake(session);
} while (ret < 0 && gnutls_error_is_fatal(ret) == 0);
Signed-off-by: Daiki Ueno <ueno@gnu.org>
Diffstat (limited to 'lib/handshake.c')
-rw-r--r-- | lib/handshake.c | 48 |
1 files changed, 35 insertions, 13 deletions
diff --git a/lib/handshake.c b/lib/handshake.c index b40f84b3d9..ce2d160e20 100644 --- a/lib/handshake.c +++ b/lib/handshake.c @@ -2061,6 +2061,8 @@ read_server_hello(gnutls_session_t session, if (ret < 0) return gnutls_assert_val(ret); + session->internals.hsk_flags |= HSK_SERVER_HELLO_RECEIVED; + return 0; } @@ -2585,16 +2587,42 @@ int gnutls_rehandshake(gnutls_session_t session) return 0; } +/* This function checks whether the error code should be treated fatal + * or not, and also does the necessary state transition. In + * particular, in the case of a rehandshake abort it resets the + * handshake's internal state. + */ inline static int _gnutls_abort_handshake(gnutls_session_t session, int ret) { - if (((ret == GNUTLS_E_WARNING_ALERT_RECEIVED) && - (gnutls_alert_get(session) == GNUTLS_A_NO_RENEGOTIATION)) - || ret == GNUTLS_E_GOT_APPLICATION_DATA) - return 0; + switch (ret) { + case GNUTLS_E_WARNING_ALERT_RECEIVED: + if (gnutls_alert_get(session) == GNUTLS_A_NO_RENEGOTIATION) { + /* The server always toleretes a "no_renegotiation" alert. */ + if (session->security_parameters.entity == GNUTLS_SERVER) { + STATE = STATE0; + return ret; + } + + /* The client should tolerete a "no_renegotiation" alert only if: + * - the initial handshake has completed, or + * - a Server Hello is not yet received + */ + if (session->internals.initial_negotiation_completed || + !(session->internals.hsk_flags & HSK_SERVER_HELLO_RECEIVED)) { + STATE = STATE0; + return ret; + } - /* this doesn't matter */ - return GNUTLS_E_INTERNAL_ERROR; + return gnutls_assert_val(GNUTLS_E_UNEXPECTED_PACKET); + } + return ret; + case GNUTLS_E_GOT_APPLICATION_DATA: + STATE = STATE0; + return ret; + default: + return ret; + } } @@ -2756,13 +2784,7 @@ int gnutls_handshake(gnutls_session_t session) } if (ret < 0) { - /* In the case of a rehandshake abort - * we should reset the handshake's internal state. - */ - if (_gnutls_abort_handshake(session, ret) == 0) - STATE = STATE0; - - return ret; + return _gnutls_abort_handshake(session, ret); } /* clear handshake buffer */ |