Commit f20404fc authored by Matt Caswell's avatar Matt Caswell
Browse files

Don't fail on an out-of-order CCS in DTLS 



Fixes #4929

Reviewed-by: default avatarRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6170)
parent e15e92db

ssl/statem/statem.c

+1 −3
Original line number Diff line number Diff line
@@ -589,10 +589,8 @@ static SUB_STATE_RETURN read_state_machine(SSL *s) 
             * Validate that we are allowed to move to the new state and move

             * to that state if so

             */

            if (!transition(s, mt)) {

                check_fatal(s, SSL_F_READ_STATE_MACHINE);

            if (!transition(s, mt))

                return SUB_STATE_ERROR;

            }



            if (s->s3->tmp.message_size > max_message_size(s)) {

                SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_READ_STATE_MACHINE,

ssl/statem/statem_clnt.c

+14 −0
Original line number Diff line number Diff line
@@ -375,6 +375,20 @@ int ossl_statem_client_read_transition(SSL *s, int mt) 


 err:

    /* No valid transition found */

    if (SSL_IS_DTLS(s) && mt == SSL3_MT_CHANGE_CIPHER_SPEC) {

        BIO *rbio;



        /*

         * CCS messages don't have a message sequence number so this is probably

         * because of an out-of-order CCS. We'll just drop it.

         */

        s->init_num = 0;

        s->rwstate = SSL_READING;

        rbio = SSL_get_rbio(s);

        BIO_clear_retry_flags(rbio);

        BIO_set_retry_read(rbio);

        return 0;

    }

    SSLfatal(s, SSL3_AD_UNEXPECTED_MESSAGE,

             SSL_F_OSSL_STATEM_CLIENT_READ_TRANSITION,

             SSL_R_UNEXPECTED_MESSAGE);

ssl/statem/statem_srvr.c

+14 −0
Original line number Diff line number Diff line
@@ -277,6 +277,20 @@ int ossl_statem_server_read_transition(SSL *s, int mt) 


 err:

    /* No valid transition found */

    if (SSL_IS_DTLS(s) && mt == SSL3_MT_CHANGE_CIPHER_SPEC) {

        BIO *rbio;



        /*

         * CCS messages don't have a message sequence number so this is probably

         * because of an out-of-order CCS. We'll just drop it.

         */

        s->init_num = 0;

        s->rwstate = SSL_READING;

        rbio = SSL_get_rbio(s);

        BIO_clear_retry_flags(rbio);

        BIO_set_retry_read(rbio);

        return 0;

    }

    SSLfatal(s, SSL3_AD_UNEXPECTED_MESSAGE,

             SSL_F_OSSL_STATEM_SERVER_READ_TRANSITION,

             SSL_R_UNEXPECTED_MESSAGE);