Exemple #1
0
static int test_PACKET_get_net_3()
{
    unsigned long i;
    PACKET pkt;

    if (!TEST_true(PACKET_buf_init(&pkt, smbuf, BUF_LEN))
            || !TEST_true(PACKET_get_net_3(&pkt, &i))
            || !TEST_ulong_eq(i, 0x020406UL)
            || !TEST_true(PACKET_forward(&pkt, BUF_LEN - 6))
            || !TEST_true(PACKET_get_net_3(&pkt, &i))
            || !TEST_ulong_eq(i, 0xfafcfeUL)
            || !TEST_false(PACKET_get_net_3(&pkt, &i)))
        return 0;

    return 1;
}
static int test_PACKET_get_net_3(PACKET *pkt, size_t start)
{
    unsigned long i;

    if (       !PACKET_goto_bookmark(pkt, start)
            || !PACKET_get_net_3(pkt, &i)
            ||  i != 0x020406UL
            || !PACKET_forward(pkt, BUF_LEN - 6)
            || !PACKET_get_net_3(pkt, &i)
            ||  i != 0xfafcfeUL
            ||  PACKET_get_net_3(pkt, &i)) {
        fprintf(stderr, "test_PACKET_get_net_3() failed\n");
        return 0;
    }

    return 1;
}
Exemple #3
0
static int test_PACKET_get_net_3(unsigned char buf[BUF_LEN])
{
    unsigned long i;
    PACKET pkt;

    if (       !PACKET_buf_init(&pkt, buf, BUF_LEN)
            || !PACKET_get_net_3(&pkt, &i)
            ||  i != 0x020406UL
            || !PACKET_forward(&pkt, BUF_LEN - 6)
            || !PACKET_get_net_3(&pkt, &i)
            ||  i != 0xfafcfeUL
            ||  PACKET_get_net_3(&pkt, &i)) {
        fprintf(stderr, "test_PACKET_get_net_3() failed\n");
        return 0;
    }

    return 1;
}
Exemple #4
0
int DTLSv1_listen(SSL *s, BIO_ADDR *client)
{
    int next, n, ret = 0, clearpkt = 0;
    unsigned char cookie[DTLS1_COOKIE_LENGTH];
    unsigned char seq[SEQ_NUM_SIZE];
    const unsigned char *data;
    unsigned char *p, *buf;
    unsigned long reclen, fragoff, fraglen, msglen;
    unsigned int rectype, versmajor, msgseq, msgtype, clientvers, cookielen;
    BIO *rbio, *wbio;
    BUF_MEM *bufm;
    BIO_ADDR *tmpclient = NULL;
    PACKET pkt, msgpkt, msgpayload, session, cookiepkt;

    /* Ensure there is no state left over from a previous invocation */
    if (!SSL_clear(s))
        return -1;

    ERR_clear_error();

    rbio = SSL_get_rbio(s);
    wbio = SSL_get_wbio(s);

    if (!rbio || !wbio) {
        SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_BIO_NOT_SET);
        return -1;
    }

    /*
     * We only peek at incoming ClientHello's until we're sure we are going to
     * to respond with a HelloVerifyRequest. If its a ClientHello with a valid
     * cookie then we leave it in the BIO for accept to handle.
     */
    BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 1, NULL);

    /*
     * Note: This check deliberately excludes DTLS1_BAD_VER because that version
     * requires the MAC to be calculated *including* the first ClientHello
     * (without the cookie). Since DTLSv1_listen is stateless that cannot be
     * supported. DTLS1_BAD_VER must use cookies in a stateful manner (e.g. via
     * SSL_accept)
     */
    if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00)) {
        SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNSUPPORTED_SSL_VERSION);
        return -1;
    }

    if (s->init_buf == NULL) {
        if ((bufm = BUF_MEM_new()) == NULL) {
            SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_MALLOC_FAILURE);
            return -1;
        }

        if (!BUF_MEM_grow(bufm, SSL3_RT_MAX_PLAIN_LENGTH)) {
            BUF_MEM_free(bufm);
            SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_MALLOC_FAILURE);
            return -1;
        }
        s->init_buf = bufm;
    }
    buf = (unsigned char *)s->init_buf->data;

    do {
        /* Get a packet */

        clear_sys_error();
        /*
         * Technically a ClientHello could be SSL3_RT_MAX_PLAIN_LENGTH
         * + DTLS1_RT_HEADER_LENGTH bytes long. Normally init_buf does not store
         * the record header as well, but we do here. We've set up init_buf to
         * be the standard size for simplicity. In practice we shouldn't ever
         * receive a ClientHello as long as this. If we do it will get dropped
         * in the record length check below.
         */
        n = BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH);

        if (n <= 0) {
            if (BIO_should_retry(rbio)) {
                /* Non-blocking IO */
                goto end;
            }
            return -1;
        }

        /* If we hit any problems we need to clear this packet from the BIO */
        clearpkt = 1;

        if (!PACKET_buf_init(&pkt, buf, n)) {
            SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_INTERNAL_ERROR);
            return -1;
        }

        /*
         * Parse the received record. If there are any problems with it we just
         * dump it - with no alert. RFC6347 says this "Unlike TLS, DTLS is
         * resilient in the face of invalid records (e.g., invalid formatting,
         * length, MAC, etc.).  In general, invalid records SHOULD be silently
         * discarded, thus preserving the association; however, an error MAY be
         * logged for diagnostic purposes."
         */

        /* this packet contained a partial record, dump it */
        if (n < DTLS1_RT_HEADER_LENGTH) {
            SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_RECORD_TOO_SMALL);
            goto end;
        }

        if (s->msg_callback)
            s->msg_callback(0, 0, SSL3_RT_HEADER, buf,
                            DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg);

        /* Get the record header */
        if (!PACKET_get_1(&pkt, &rectype)
            || !PACKET_get_1(&pkt, &versmajor)) {
            SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH);
            goto end;
        }

        if (rectype != SSL3_RT_HANDSHAKE) {
            SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNEXPECTED_MESSAGE);
            goto end;
        }

        /*
         * Check record version number. We only check that the major version is
         * the same.
         */
        if (versmajor != DTLS1_VERSION_MAJOR) {
            SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_BAD_PROTOCOL_VERSION_NUMBER);
            goto end;
        }

        if (!PACKET_forward(&pkt, 1)
            /* Save the sequence number: 64 bits, with top 2 bytes = epoch */
            || !PACKET_copy_bytes(&pkt, seq, SEQ_NUM_SIZE)
            || !PACKET_get_length_prefixed_2(&pkt, &msgpkt)) {
            SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH);
            goto end;
        }
        /*
         * We allow data remaining at the end of the packet because there could
         * be a second record (but we ignore it)
         */

        /* This is an initial ClientHello so the epoch has to be 0 */
        if (seq[0] != 0 || seq[1] != 0) {
            SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNEXPECTED_MESSAGE);
            goto end;
        }

        /* Get a pointer to the raw message for the later callback */
        data = PACKET_data(&msgpkt);

        /* Finished processing the record header, now process the message */
        if (!PACKET_get_1(&msgpkt, &msgtype)
            || !PACKET_get_net_3(&msgpkt, &msglen)
            || !PACKET_get_net_2(&msgpkt, &msgseq)
            || !PACKET_get_net_3(&msgpkt, &fragoff)
            || !PACKET_get_net_3(&msgpkt, &fraglen)
            || !PACKET_get_sub_packet(&msgpkt, &msgpayload, fraglen)
            || PACKET_remaining(&msgpkt) != 0) {
            SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH);
            goto end;
        }

        if (msgtype != SSL3_MT_CLIENT_HELLO) {
            SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNEXPECTED_MESSAGE);
            goto end;
        }

        /* Message sequence number can only be 0 or 1 */
        if (msgseq > 2) {
            SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_INVALID_SEQUENCE_NUMBER);
            goto end;
        }

        /*
         * We don't support fragment reassembly for ClientHellos whilst
         * listening because that would require server side state (which is
         * against the whole point of the ClientHello/HelloVerifyRequest
         * mechanism). Instead we only look at the first ClientHello fragment
         * and require that the cookie must be contained within it.
         */
        if (fragoff != 0 || fraglen > msglen) {
            /* Non initial ClientHello fragment (or bad fragment) */
            SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_FRAGMENTED_CLIENT_HELLO);
            goto end;
        }

        if (s->msg_callback)
            s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, data,
                            fraglen + DTLS1_HM_HEADER_LENGTH, s,
                            s->msg_callback_arg);

        if (!PACKET_get_net_2(&msgpayload, &clientvers)) {
            SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH);
            goto end;
        }

        /*
         * Verify client version is supported
         */
        if (DTLS_VERSION_LT(clientvers, (unsigned int)s->method->version) &&
            s->method->version != DTLS_ANY_VERSION) {
            SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_WRONG_VERSION_NUMBER);
            goto end;
        }

        if (!PACKET_forward(&msgpayload, SSL3_RANDOM_SIZE)
            || !PACKET_get_length_prefixed_1(&msgpayload, &session)
            || !PACKET_get_length_prefixed_1(&msgpayload, &cookiepkt)) {
            /*
             * Could be malformed or the cookie does not fit within the initial
             * ClientHello fragment. Either way we can't handle it.
             */
            SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH);
            goto end;
        }

        /*
         * Check if we have a cookie or not. If not we need to send a
         * HelloVerifyRequest.
         */
        if (PACKET_remaining(&cookiepkt) == 0) {
            next = LISTEN_SEND_VERIFY_REQUEST;
        } else {
            /*
             * We have a cookie, so lets check it.
             */
            if (s->ctx->app_verify_cookie_cb == NULL) {
                SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_NO_VERIFY_COOKIE_CALLBACK);
                /* This is fatal */
                return -1;
            }
            if (s->ctx->app_verify_cookie_cb(s, PACKET_data(&cookiepkt),
                                             PACKET_remaining(&cookiepkt)) ==
                0) {
                /*
                 * We treat invalid cookies in the same was as no cookie as
                 * per RFC6347
                 */
                next = LISTEN_SEND_VERIFY_REQUEST;
            } else {
                /* Cookie verification succeeded */
                next = LISTEN_SUCCESS;
            }
        }

        if (next == LISTEN_SEND_VERIFY_REQUEST) {
            /*
             * There was no cookie in the ClientHello so we need to send a
             * HelloVerifyRequest. If this fails we do not worry about trying
             * to resend, we just drop it.
             */

            /*
             * Dump the read packet, we don't need it any more. Ignore return
             * value
             */
            BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 0, NULL);
            BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH);
            BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 1, NULL);

            /* Generate the cookie */
            if (s->ctx->app_gen_cookie_cb == NULL ||
                s->ctx->app_gen_cookie_cb(s, cookie, &cookielen) == 0 ||
                cookielen > 255) {
                SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_COOKIE_GEN_CALLBACK_FAILURE);
                /* This is fatal */
                return -1;
            }

            p = &buf[DTLS1_RT_HEADER_LENGTH];
            msglen = dtls_raw_hello_verify_request(p + DTLS1_HM_HEADER_LENGTH,
                                                   cookie, cookielen);

            *p++ = DTLS1_MT_HELLO_VERIFY_REQUEST;

            /* Message length */
            l2n3(msglen, p);

            /* Message sequence number is always 0 for a HelloVerifyRequest */
            s2n(0, p);

            /*
             * We never fragment a HelloVerifyRequest, so fragment offset is 0
             * and fragment length is message length
             */
            l2n3(0, p);
            l2n3(msglen, p);

            /* Set reclen equal to length of whole handshake message */
            reclen = msglen + DTLS1_HM_HEADER_LENGTH;

            /* Add the record header */
            p = buf;

            *(p++) = SSL3_RT_HANDSHAKE;
            /*
             * Special case: for hello verify request, client version 1.0 and we
             * haven't decided which version to use yet send back using version
             * 1.0 header: otherwise some clients will ignore it.
             */
            if (s->method->version == DTLS_ANY_VERSION) {
                *(p++) = DTLS1_VERSION >> 8;
                *(p++) = DTLS1_VERSION & 0xff;
            } else {
                *(p++) = s->version >> 8;
                *(p++) = s->version & 0xff;
            }

            /*
             * Record sequence number is always the same as in the received
             * ClientHello
             */
            memcpy(p, seq, SEQ_NUM_SIZE);
            p += SEQ_NUM_SIZE;

            /* Length */
            s2n(reclen, p);

            /*
             * Set reclen equal to length of whole record including record
             * header
             */
            reclen += DTLS1_RT_HEADER_LENGTH;

            if (s->msg_callback)
                s->msg_callback(1, 0, SSL3_RT_HEADER, buf,
                                DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg);

            if ((tmpclient = BIO_ADDR_new()) == NULL) {
                SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_MALLOC_FAILURE);
                goto end;
            }

            /*
             * This is unnecessary if rbio and wbio are one and the same - but
             * maybe they're not. We ignore errors here - some BIOs do not
             * support this.
             */
            if (BIO_dgram_get_peer(rbio, tmpclient) > 0) {
                (void)BIO_dgram_set_peer(wbio, tmpclient);
            }
            BIO_ADDR_free(tmpclient);
            tmpclient = NULL;

            if (BIO_write(wbio, buf, reclen) < (int)reclen) {
                if (BIO_should_retry(wbio)) {
                    /*
                     * Non-blocking IO...but we're stateless, so we're just
                     * going to drop this packet.
                     */
                    goto end;
                }
                return -1;
            }

            if (BIO_flush(wbio) <= 0) {
                if (BIO_should_retry(wbio)) {
                    /*
                     * Non-blocking IO...but we're stateless, so we're just
                     * going to drop this packet.
                     */
                    goto end;
                }
                return -1;
            }
        }