Commit message: Multiblock corrupted pointer fix

OpenSSL 1.0.2 introduced the "multiblock" performance improvement. This
feature only applies on 64 bit x86 architecture platforms that support AES
NI instructions. A defect in the implementation of "multiblock" can cause
OpenSSL's internal write buffer to become incorrectly set to NULL when
using non-blocking IO. Typically, when the user application is using a
socket BIO for writing, this will only result in a failed connection.
However if some other BIO is used then it is likely that a segmentation
fault will be triggered, thus enabling a potential DoS attack.

CVE-2015-0290

Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Andy Polyakov <appro@openssl.org>
CVE: CVE-2015-0290
CWE: CWE-17
Vulnerability description: The multi-block feature in the ssl3_write_bytes function in s3_pkt.c in OpenSSL 1.0.2 before 1.0.2a on 64-bit x86 platforms with AES NI support does not properly handle certain non-blocking I/O cases, which allows remote attackers to cause a denial of service (pointer corruption and application crash) via unspecified vectors.

Project: openssl

static int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
                         unsigned int len, int create_empty_fragment)
{
    unsigned char *p, *plen;
    int i, mac_size, clear = 0;
    int prefix_len = 0;
    int eivlen;
    long align = 0;
    SSL3_RECORD *wr;
    SSL3_BUFFER *wb = &(s->s3->wbuf);
    SSL_SESSION *sess;

    /*
     * first check if there is a SSL3_BUFFER still being written out.  This
     * will happen with non blocking IO
     */
    if (wb->left != 0)
        return (ssl3_write_pending(s, type, buf, len));

    /* If we have an alert to send, lets send it */
    if (s->s3->alert_dispatch) {
        i = s->method->ssl_dispatch_alert(s);
        if (i <= 0)
            return (i);
        /* if it went, fall through and send more stuff */
    }

    if (wb->buf == NULL)
        if (!ssl3_setup_write_buffer(s))
            return -1;

    if (len == 0 && !create_empty_fragment)
        return 0;

    wr = &(s->s3->wrec);
    sess = s->session;

    if ((sess == NULL) ||
        (s->enc_write_ctx == NULL) ||
        (EVP_MD_CTX_md(s->write_hash) == NULL)) {
#if 1
        clear = s->enc_write_ctx ? 0 : 1; /* must be AEAD cipher */
#else
        clear = 1;
#endif
        mac_size = 0;
    } else {
        mac_size = EVP_MD_CTX_size(s->write_hash);
        if (mac_size < 0)
            goto err;
    }

    /*
     * 'create_empty_fragment' is true only when this function calls itself
     */
    if (!clear && !create_empty_fragment && !s->s3->empty_fragment_done) {
        /*
         * countermeasure against known-IV weakness in CBC ciphersuites (see
         * http://www.openssl.org/~bodo/tls-cbc.txt)
         */

        if (s->s3->need_empty_fragments && type == SSL3_RT_APPLICATION_DATA) {
            /*
             * recursive function call with 'create_empty_fragment' set; this
             * prepares and buffers the data for an empty fragment (these
             * 'prefix_len' bytes are sent out later together with the actual
             * payload)
             */
            prefix_len = do_ssl3_write(s, type, buf, 0, 1);
            if (prefix_len <= 0)
                goto err;

            if (prefix_len >
                (SSL3_RT_HEADER_LENGTH + SSL3_RT_SEND_MAX_ENCRYPTED_OVERHEAD))
            {
                /* insufficient space */
                SSLerr(SSL_F_DO_SSL3_WRITE, ERR_R_INTERNAL_ERROR);
                goto err;
            }
        }

        s->s3->empty_fragment_done = 1;
    }

    if (create_empty_fragment) {
#if defined(SSL3_ALIGN_PAYLOAD) && SSL3_ALIGN_PAYLOAD!=0
        /*
         * extra fragment would be couple of cipher blocks, which would be
         * multiple of SSL3_ALIGN_PAYLOAD, so if we want to align the real
         * payload, then we can just pretent we simply have two headers.
         */
        align = (long)wb->buf + 2 * SSL3_RT_HEADER_LENGTH;
        align = (-align) & (SSL3_ALIGN_PAYLOAD - 1);
#endif
        p = wb->buf + align;
        wb->offset = align;
    } else if (prefix_len) {
        p = wb->buf + wb->offset + prefix_len;
    } else {
#if defined(SSL3_ALIGN_PAYLOAD) && SSL3_ALIGN_PAYLOAD!=0
        align = (long)wb->buf + SSL3_RT_HEADER_LENGTH;
        align = (-align) & (SSL3_ALIGN_PAYLOAD - 1);
#endif
        p = wb->buf + align;
        wb->offset = align;
    }

    /* write the header */

    *(p++) = type & 0xff;
    wr->type = type;

    *(p++) = (s->version >> 8);
    /*
     * Some servers hang if iniatial client hello is larger than 256 bytes
     * and record version number > TLS 1.0
     */
    if (s->state == SSL3_ST_CW_CLNT_HELLO_B
        && !s->renegotiate && TLS1_get_version(s) > TLS1_VERSION)
        *(p++) = 0x1;
    else
        *(p++) = s->version & 0xff;

    /* field where we are to write out packet length */
    plen = p;
    p += 2;
    /* Explicit IV length, block ciphers appropriate version flag */
    if (s->enc_write_ctx && SSL_USE_EXPLICIT_IV(s)) {
        int mode = EVP_CIPHER_CTX_mode(s->enc_write_ctx);
        if (mode == EVP_CIPH_CBC_MODE) {
            eivlen = EVP_CIPHER_CTX_iv_length(s->enc_write_ctx);
            if (eivlen <= 1)
                eivlen = 0;
        }
        /* Need explicit part of IV for GCM mode */
        else if (mode == EVP_CIPH_GCM_MODE)
            eivlen = EVP_GCM_TLS_EXPLICIT_IV_LEN;
        else
            eivlen = 0;
    } else
        eivlen = 0;

    /* lets setup the record stuff. */
    wr->data = p + eivlen;
    wr->length = (int)len;
    wr->input = (unsigned char *)buf;

    /*
     * we now 'read' from wr->input, wr->length bytes into wr->data
     */

    /* first we compress */
    if (s->compress != NULL) {
        if (!ssl3_do_compress(s)) {
            SSLerr(SSL_F_DO_SSL3_WRITE, SSL_R_COMPRESSION_FAILURE);
            goto err;
        }
    } else {
        memcpy(wr->data, wr->input, wr->length);
        wr->input = wr->data;
    }

    /*
     * we should still have the output to wr->data and the input from
     * wr->input.  Length should be wr->length. wr->data still points in the
     * wb->buf
     */

    if (mac_size != 0) {
        if (s->method->ssl3_enc->mac(s, &(p[wr->length + eivlen]), 1) < 0)
            goto err;
        wr->length += mac_size;
    }

    wr->input = p;
    wr->data = p;

    if (eivlen) {
        /*
         * if (RAND_pseudo_bytes(p, eivlen) <= 0) goto err;
         */
        wr->length += eivlen;
    }

    if (s->method->ssl3_enc->enc(s, 1) < 1)
        goto err;

    /* record length after mac and block padding */
    s2n(wr->length, plen);

    if (s->msg_callback)
        s->msg_callback(1, 0, SSL3_RT_HEADER, plen - 5, 5, s,
                        s->msg_callback_arg);

    /*
     * we should now have wr->data pointing to the encrypted data, which is
     * wr->length long
     */
    wr->type = type;            /* not needed but helps for debugging */
    wr->length += SSL3_RT_HEADER_LENGTH;

    if (create_empty_fragment) {
        /*
         * we are in a recursive call; just return the length, don't write
         * out anything here
         */
        return wr->length;
    }

    /* now let's set up wb */
    wb->left = prefix_len + wr->length;

    /*
     * memorize arguments so that ssl3_write_pending can detect bad write
     * retries later
     */
    s->s3->wpend_tot = len;
    s->s3->wpend_buf = buf;
    s->s3->wpend_type = type;
    s->s3->wpend_ret = len;

    /* we now just need to write the buffer */
    return ssl3_write_pending(s, type, buf, len);
 err:
    return -1;
}

Project: openssl

int ssl3_dispatch_alert(SSL *s)
{
    int i, j;
    void (*cb) (const SSL *ssl, int type, int val) = NULL;

    s->s3->alert_dispatch = 0;
    i = do_ssl3_write(s, SSL3_RT_ALERT, &s->s3->send_alert[0], 2, 0);
    if (i <= 0) {
        s->s3->alert_dispatch = 1;
    } else {
        /*
         * Alert sent to BIO.  If it is important, flush it now. If the
         * message does not get sent due to non-blocking IO, we will not
         * worry too much.
         */
        if (s->s3->send_alert[0] == SSL3_AL_FATAL)
            (void)BIO_flush(s->wbio);

        if (s->msg_callback)
            s->msg_callback(1, s->version, SSL3_RT_ALERT, s->s3->send_alert,
                            2, s, s->msg_callback_arg);

        if (s->info_callback != NULL)
            cb = s->info_callback;
        else if (s->ctx->info_callback != NULL)
            cb = s->ctx->info_callback;

        if (cb != NULL) {
            j = (s->s3->send_alert[0] << 8) | s->s3->send_alert[1];
            cb(s, SSL_CB_WRITE_ALERT, j);
        }
    }
    return (i);
}

Project: openssl

int ssl3_do_change_cipher_spec(SSL *s)
{
    int i;
    const char *sender;
    int slen;

    if (s->state & SSL_ST_ACCEPT)
        i = SSL3_CHANGE_CIPHER_SERVER_READ;
    else
        i = SSL3_CHANGE_CIPHER_CLIENT_READ;

    if (s->s3->tmp.key_block == NULL) {
        if (s->session == NULL || s->session->master_key_length == 0) {
            /* might happen if dtls1_read_bytes() calls this */
            SSLerr(SSL_F_SSL3_DO_CHANGE_CIPHER_SPEC,
                   SSL_R_CCS_RECEIVED_EARLY);
            return (0);
        }

        s->session->cipher = s->s3->tmp.new_cipher;
        if (!s->method->ssl3_enc->setup_key_block(s))
            return (0);
    }

    if (!s->method->ssl3_enc->change_cipher_state(s, i))
        return (0);

    /*
     * we have to record the message digest at this point so we can get it
     * before we read the finished message
     */
    if (s->state & SSL_ST_CONNECT) {
        sender = s->method->ssl3_enc->server_finished_label;
        slen = s->method->ssl3_enc->server_finished_label_len;
    } else {
        sender = s->method->ssl3_enc->client_finished_label;
        slen = s->method->ssl3_enc->client_finished_label_len;
    }

    i = s->method->ssl3_enc->final_finish_mac(s,
                                              sender, slen,
                                              s->s3->tmp.peer_finish_md);
    if (i == 0) {
        SSLerr(SSL_F_SSL3_DO_CHANGE_CIPHER_SPEC, ERR_R_INTERNAL_ERROR);
        return 0;
    }
    s->s3->tmp.peer_finish_md_len = i;

    return (1);
}

Project: openssl

int ssl3_do_compress(SSL *ssl)
{
#ifndef OPENSSL_NO_COMP
    int i;
    SSL3_RECORD *wr;

    wr = &(ssl->s3->wrec);
    i = COMP_compress_block(ssl->compress, wr->data,
                            SSL3_RT_MAX_COMPRESSED_LENGTH,
                            wr->input, (int)wr->length);
    if (i < 0)
        return (0);
    else
        wr->length = i;

    wr->input = wr->data;
#endif
    return (1);
}

Project: openssl

int ssl3_do_uncompress(SSL *ssl)
{
#ifndef OPENSSL_NO_COMP
    int i;
    SSL3_RECORD *rr;

    rr = &(ssl->s3->rrec);
    i = COMP_expand_block(ssl->expand, rr->comp,
                          SSL3_RT_MAX_PLAIN_LENGTH, rr->data,
                          (int)rr->length);
    if (i < 0)
        return (0);
    else
        rr->length = i;
    rr->data = rr->comp;
#endif
    return (1);
}

Project: openssl

int ssl3_read_bytes(SSL *s, int type, unsigned char *buf, int len, int peek)
{
    int al, i, j, ret;
    unsigned int n;
    SSL3_RECORD *rr;
    void (*cb) (const SSL *ssl, int type2, int val) = NULL;

    if (s->s3->rbuf.buf == NULL) /* Not initialized yet */
        if (!ssl3_setup_read_buffer(s))
            return (-1);

    if ((type && (type != SSL3_RT_APPLICATION_DATA)
         && (type != SSL3_RT_HANDSHAKE)) || (peek
                                             && (type !=
                                                 SSL3_RT_APPLICATION_DATA))) {
        SSLerr(SSL_F_SSL3_READ_BYTES, ERR_R_INTERNAL_ERROR);
        return -1;
    }

    if ((type == SSL3_RT_HANDSHAKE) && (s->s3->handshake_fragment_len > 0))
        /* (partially) satisfy request from storage */
    {
        unsigned char *src = s->s3->handshake_fragment;
        unsigned char *dst = buf;
        unsigned int k;

        /* peek == 0 */
        n = 0;
        while ((len > 0) && (s->s3->handshake_fragment_len > 0)) {
            *dst++ = *src++;
            len--;
            s->s3->handshake_fragment_len--;
            n++;
        }
        /* move any remaining fragment bytes: */
        for (k = 0; k < s->s3->handshake_fragment_len; k++)
            s->s3->handshake_fragment[k] = *src++;
        return n;
    }

    /*
     * Now s->s3->handshake_fragment_len == 0 if type == SSL3_RT_HANDSHAKE.
     */

    if (!s->in_handshake && SSL_in_init(s)) {
        /* type == SSL3_RT_APPLICATION_DATA */
        i = s->handshake_func(s);
        if (i < 0)
            return (i);
        if (i == 0) {
            SSLerr(SSL_F_SSL3_READ_BYTES, SSL_R_SSL_HANDSHAKE_FAILURE);
            return (-1);
        }
    }
 start:
    s->rwstate = SSL_NOTHING;

    /*-
     * s->s3->rrec.type         - is the type of record
     * s->s3->rrec.data,    - data
     * s->s3->rrec.off,     - offset into 'data' for next read
     * s->s3->rrec.length,  - number of bytes.
     */
    rr = &(s->s3->rrec);

    /* get new packet if necessary */
    if ((rr->length == 0) || (s->rstate == SSL_ST_READ_BODY)) {
        ret = ssl3_get_record(s);
        if (ret <= 0)
            return (ret);
    }

    /* we now have a packet which can be read and processed */

    if (s->s3->change_cipher_spec /* set when we receive ChangeCipherSpec,
                                   * reset by ssl3_get_finished */
        && (rr->type != SSL3_RT_HANDSHAKE)) {
        al = SSL_AD_UNEXPECTED_MESSAGE;
        SSLerr(SSL_F_SSL3_READ_BYTES, SSL_R_DATA_BETWEEN_CCS_AND_FINISHED);
        goto f_err;
    }

    /*
     * If the other end has shut down, throw anything we read away (even in
     * 'peek' mode)
     */
    if (s->shutdown & SSL_RECEIVED_SHUTDOWN) {
        rr->length = 0;
        s->rwstate = SSL_NOTHING;
        return (0);
    }

    if (type == rr->type) {     /* SSL3_RT_APPLICATION_DATA or
                                 * SSL3_RT_HANDSHAKE */
        /*
         * make sure that we are not getting application data when we are
         * doing a handshake for the first time
         */
        if (SSL_in_init(s) && (type == SSL3_RT_APPLICATION_DATA) &&
            (s->enc_read_ctx == NULL)) {
            al = SSL_AD_UNEXPECTED_MESSAGE;
            SSLerr(SSL_F_SSL3_READ_BYTES, SSL_R_APP_DATA_IN_HANDSHAKE);
            goto f_err;
        }

        if (len <= 0)
            return (len);

        if ((unsigned int)len > rr->length)
            n = rr->length;
        else
            n = (unsigned int)len;

        memcpy(buf, &(rr->data[rr->off]), n);
        if (!peek) {
            rr->length -= n;
            rr->off += n;
            if (rr->length == 0) {
                s->rstate = SSL_ST_READ_HEADER;
                rr->off = 0;
                if (s->mode & SSL_MODE_RELEASE_BUFFERS
                    && s->s3->rbuf.left == 0)
                    ssl3_release_read_buffer(s);
            }
        }
        return (n);
    }

    /*
     * If we get here, then type != rr->type; if we have a handshake message,
     * then it was unexpected (Hello Request or Client Hello).
     */

    /*
     * In case of record types for which we have 'fragment' storage, fill
     * that so that we can process the data at a fixed place.
     */
    {
        unsigned int dest_maxlen = 0;
        unsigned char *dest = NULL;
        unsigned int *dest_len = NULL;

        if (rr->type == SSL3_RT_HANDSHAKE) {
            dest_maxlen = sizeof s->s3->handshake_fragment;
            dest = s->s3->handshake_fragment;
            dest_len = &s->s3->handshake_fragment_len;
        } else if (rr->type == SSL3_RT_ALERT) {
            dest_maxlen = sizeof s->s3->alert_fragment;
            dest = s->s3->alert_fragment;
            dest_len = &s->s3->alert_fragment_len;
        }
#ifndef OPENSSL_NO_HEARTBEATS
        else if (rr->type == TLS1_RT_HEARTBEAT) {
            tls1_process_heartbeat(s);

            /* Exit and notify application to read again */
            rr->length = 0;
            s->rwstate = SSL_READING;
            BIO_clear_retry_flags(SSL_get_rbio(s));
            BIO_set_retry_read(SSL_get_rbio(s));
            return (-1);
        }
#endif

        if (dest_maxlen > 0) {
            n = dest_maxlen - *dest_len; /* available space in 'dest' */
            if (rr->length < n)
                n = rr->length; /* available bytes */

            /* now move 'n' bytes: */
            while (n-- > 0) {
                dest[(*dest_len)++] = rr->data[rr->off++];
                rr->length--;
            }

            if (*dest_len < dest_maxlen)
                goto start;     /* fragment was too small */
        }
    }

    /*-
     * s->s3->handshake_fragment_len == 4  iff  rr->type == SSL3_RT_HANDSHAKE;
     * s->s3->alert_fragment_len == 2      iff  rr->type == SSL3_RT_ALERT.
     * (Possibly rr is 'empty' now, i.e. rr->length may be 0.)
     */

    /* If we are a client, check for an incoming 'Hello Request': */
    if ((!s->server) &&
        (s->s3->handshake_fragment_len >= 4) &&
        (s->s3->handshake_fragment[0] == SSL3_MT_HELLO_REQUEST) &&
        (s->session != NULL) && (s->session->cipher != NULL)) {
        s->s3->handshake_fragment_len = 0;

        if ((s->s3->handshake_fragment[1] != 0) ||
            (s->s3->handshake_fragment[2] != 0) ||
            (s->s3->handshake_fragment[3] != 0)) {
            al = SSL_AD_DECODE_ERROR;
            SSLerr(SSL_F_SSL3_READ_BYTES, SSL_R_BAD_HELLO_REQUEST);
            goto f_err;
        }

        if (s->msg_callback)
            s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
                            s->s3->handshake_fragment, 4, s,
                            s->msg_callback_arg);

        if (SSL_is_init_finished(s) &&
            !(s->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS) &&
            !s->s3->renegotiate) {
            ssl3_renegotiate(s);
            if (ssl3_renegotiate_check(s)) {
                i = s->handshake_func(s);
                if (i < 0)
                    return (i);
                if (i == 0) {
                    SSLerr(SSL_F_SSL3_READ_BYTES,
                           SSL_R_SSL_HANDSHAKE_FAILURE);
                    return (-1);
                }

                if (!(s->mode & SSL_MODE_AUTO_RETRY)) {
                    if (s->s3->rbuf.left == 0) { /* no read-ahead left? */
                        BIO *bio;
                        /*
                         * In the case where we try to read application data,
                         * but we trigger an SSL handshake, we return -1 with
                         * the retry option set.  Otherwise renegotiation may
                         * cause nasty problems in the blocking world
                         */
                        s->rwstate = SSL_READING;
                        bio = SSL_get_rbio(s);
                        BIO_clear_retry_flags(bio);
                        BIO_set_retry_read(bio);
                        return (-1);
                    }
                }
            }
        }
        /*
         * we either finished a handshake or ignored the request, now try
         * again to obtain the (application) data we were asked for
         */
        goto start;
    }
    /*
     * If we are a server and get a client hello when renegotiation isn't
     * allowed send back a no renegotiation alert and carry on. WARNING:
     * experimental code, needs reviewing (steve)
     */
    if (s->server &&
        SSL_is_init_finished(s) &&
        !s->s3->send_connection_binding &&
        (s->version > SSL3_VERSION) &&
        (s->s3->handshake_fragment_len >= 4) &&
        (s->s3->handshake_fragment[0] == SSL3_MT_CLIENT_HELLO) &&
        (s->session != NULL) && (s->session->cipher != NULL) &&
        !(s->ctx->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION)) {
        /*
         * s->s3->handshake_fragment_len = 0;
         */
        rr->length = 0;
        ssl3_send_alert(s, SSL3_AL_WARNING, SSL_AD_NO_RENEGOTIATION);
        goto start;
    }
    if (s->s3->alert_fragment_len >= 2) {
        int alert_level = s->s3->alert_fragment[0];
        int alert_descr = s->s3->alert_fragment[1];

        s->s3->alert_fragment_len = 0;

        if (s->msg_callback)
            s->msg_callback(0, s->version, SSL3_RT_ALERT,
                            s->s3->alert_fragment, 2, s, s->msg_callback_arg);

        if (s->info_callback != NULL)
            cb = s->info_callback;
        else if (s->ctx->info_callback != NULL)
            cb = s->ctx->info_callback;

        if (cb != NULL) {
            j = (alert_level << 8) | alert_descr;
            cb(s, SSL_CB_READ_ALERT, j);
        }

        if (alert_level == SSL3_AL_WARNING) {
            s->s3->warn_alert = alert_descr;
            if (alert_descr == SSL_AD_CLOSE_NOTIFY) {
                s->shutdown |= SSL_RECEIVED_SHUTDOWN;
                return (0);
            }
            /*
             * This is a warning but we receive it if we requested
             * renegotiation and the peer denied it. Terminate with a fatal
             * alert because if application tried to renegotiatie it
             * presumably had a good reason and expects it to succeed. In
             * future we might have a renegotiation where we don't care if
             * the peer refused it where we carry on.
             */
            else if (alert_descr == SSL_AD_NO_RENEGOTIATION) {
                al = SSL_AD_HANDSHAKE_FAILURE;
                SSLerr(SSL_F_SSL3_READ_BYTES, SSL_R_NO_RENEGOTIATION);
                goto f_err;
            }
#ifdef SSL_AD_MISSING_SRP_USERNAME
            else if (alert_descr == SSL_AD_MISSING_SRP_USERNAME)
                return (0);
#endif
        } else if (alert_level == SSL3_AL_FATAL) {
            char tmp[16];

            s->rwstate = SSL_NOTHING;
            s->s3->fatal_alert = alert_descr;
            SSLerr(SSL_F_SSL3_READ_BYTES, SSL_AD_REASON_OFFSET + alert_descr);
            BIO_snprintf(tmp, sizeof tmp, "%d", alert_descr);
            ERR_add_error_data(2, "SSL alert number ", tmp);
            s->shutdown |= SSL_RECEIVED_SHUTDOWN;
            SSL_CTX_remove_session(s->ctx, s->session);
            return (0);
        } else {
            al = SSL_AD_ILLEGAL_PARAMETER;
            SSLerr(SSL_F_SSL3_READ_BYTES, SSL_R_UNKNOWN_ALERT_TYPE);
            goto f_err;
        }

        goto start;
    }

    if (s->shutdown & SSL_SENT_SHUTDOWN) { /* but we have not received a
                                            * shutdown */
        s->rwstate = SSL_NOTHING;
        rr->length = 0;
        return (0);
    }

    if (rr->type == SSL3_RT_CHANGE_CIPHER_SPEC) {
        /*
         * 'Change Cipher Spec' is just a single byte, so we know exactly
         * what the record payload has to look like
         */
        if ((rr->length != 1) || (rr->off != 0) ||
            (rr->data[0] != SSL3_MT_CCS)) {
            al = SSL_AD_ILLEGAL_PARAMETER;
            SSLerr(SSL_F_SSL3_READ_BYTES, SSL_R_BAD_CHANGE_CIPHER_SPEC);
            goto f_err;
        }

        /* Check we have a cipher to change to */
        if (s->s3->tmp.new_cipher == NULL) {
            al = SSL_AD_UNEXPECTED_MESSAGE;
            SSLerr(SSL_F_SSL3_READ_BYTES, SSL_R_CCS_RECEIVED_EARLY);
            goto f_err;
        }

        if (!(s->s3->flags & SSL3_FLAGS_CCS_OK)) {
            al = SSL_AD_UNEXPECTED_MESSAGE;
            SSLerr(SSL_F_SSL3_READ_BYTES, SSL_R_CCS_RECEIVED_EARLY);
            goto f_err;
        }

        s->s3->flags &= ~SSL3_FLAGS_CCS_OK;

        rr->length = 0;

        if (s->msg_callback)
            s->msg_callback(0, s->version, SSL3_RT_CHANGE_CIPHER_SPEC,
                            rr->data, 1, s, s->msg_callback_arg);

        s->s3->change_cipher_spec = 1;
        if (!ssl3_do_change_cipher_spec(s))
            goto err;
        else
            goto start;
    }

    /*
     * Unexpected handshake message (Client Hello, or protocol violation)
     */
    if ((s->s3->handshake_fragment_len >= 4) && !s->in_handshake) {
        if (((s->state & SSL_ST_MASK) == SSL_ST_OK) &&
            !(s->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS)) {
#if 0                           /* worked only because C operator preferences
                                 * are not as expected (and because this is
                                 * not really needed for clients except for
                                 * detecting protocol violations): */
            s->state = SSL_ST_BEFORE | (s->server)
                ? SSL_ST_ACCEPT : SSL_ST_CONNECT;
#else
            s->state = s->server ? SSL_ST_ACCEPT : SSL_ST_CONNECT;
#endif
            s->renegotiate = 1;
            s->new_session = 1;
        }
        i = s->handshake_func(s);
        if (i < 0)
            return (i);
        if (i == 0) {
            SSLerr(SSL_F_SSL3_READ_BYTES, SSL_R_SSL_HANDSHAKE_FAILURE);
            return (-1);
        }

        if (!(s->mode & SSL_MODE_AUTO_RETRY)) {
            if (s->s3->rbuf.left == 0) { /* no read-ahead left? */
                BIO *bio;
                /*
                 * In the case where we try to read application data, but we
                 * trigger an SSL handshake, we return -1 with the retry
                 * option set.  Otherwise renegotiation may cause nasty
                 * problems in the blocking world
                 */
                s->rwstate = SSL_READING;
                bio = SSL_get_rbio(s);
                BIO_clear_retry_flags(bio);
                BIO_set_retry_read(bio);
                return (-1);
            }
        }
        goto start;
    }

    switch (rr->type) {
    default:
#ifndef OPENSSL_NO_TLS
        /*
         * TLS up to v1.1 just ignores unknown message types: TLS v1.2 give
         * an unexpected message alert.
         */
        if (s->version >= TLS1_VERSION && s->version <= TLS1_1_VERSION) {
            rr->length = 0;
            goto start;
        }
#endif
        al = SSL_AD_UNEXPECTED_MESSAGE;
        SSLerr(SSL_F_SSL3_READ_BYTES, SSL_R_UNEXPECTED_RECORD);
        goto f_err;
    case SSL3_RT_CHANGE_CIPHER_SPEC:
    case SSL3_RT_ALERT:
    case SSL3_RT_HANDSHAKE:
        /*
         * we already handled all of these, with the possible exception of
         * SSL3_RT_HANDSHAKE when s->in_handshake is set, but that should not
         * happen when type != rr->type
         */
        al = SSL_AD_UNEXPECTED_MESSAGE;
        SSLerr(SSL_F_SSL3_READ_BYTES, ERR_R_INTERNAL_ERROR);
        goto f_err;
    case SSL3_RT_APPLICATION_DATA:
        /*
         * At this point, we were expecting handshake data, but have
         * application data.  If the library was running inside ssl3_read()
         * (i.e. in_read_app_data is set) and it makes sense to read
         * application data at this point (session renegotiation not yet
         * started), we will indulge it.
         */
        if (s->s3->in_read_app_data &&
            (s->s3->total_renegotiations != 0) &&
            (((s->state & SSL_ST_CONNECT) &&
              (s->state >= SSL3_ST_CW_CLNT_HELLO_A) &&
              (s->state <= SSL3_ST_CR_SRVR_HELLO_A)
             ) || ((s->state & SSL_ST_ACCEPT) &&
                   (s->state <= SSL3_ST_SW_HELLO_REQ_A) &&
                   (s->state >= SSL3_ST_SR_CLNT_HELLO_A)
             )
            )) {
            s->s3->in_read_app_data = 2;
            return (-1);
        } else {
            al = SSL_AD_UNEXPECTED_MESSAGE;
            SSLerr(SSL_F_SSL3_READ_BYTES, SSL_R_UNEXPECTED_RECORD);
            goto f_err;
        }
    }
    /* not reached */

 f_err:
    ssl3_send_alert(s, SSL3_AL_FATAL, al);
 err:
    return (-1);
}

Project: openssl

int ssl3_read_n(SSL *s, int n, int max, int extend)
{
    /*
     * If extend == 0, obtain new n-byte packet; if extend == 1, increase
     * packet by another n bytes. The packet will be in the sub-array of
     * s->s3->rbuf.buf specified by s->packet and s->packet_length. (If
     * s->read_ahead is set, 'max' bytes may be stored in rbuf [plus
     * s->packet_length bytes if extend == 1].)
     */
    int i, len, left;
    long align = 0;
    unsigned char *pkt;
    SSL3_BUFFER *rb;

    if (n <= 0)
        return n;

    rb = &(s->s3->rbuf);
    if (rb->buf == NULL)
        if (!ssl3_setup_read_buffer(s))
            return -1;

    left = rb->left;
#if defined(SSL3_ALIGN_PAYLOAD) && SSL3_ALIGN_PAYLOAD!=0
    align = (long)rb->buf + SSL3_RT_HEADER_LENGTH;
    align = (-align) & (SSL3_ALIGN_PAYLOAD - 1);
#endif

    if (!extend) {
        /* start with empty packet ... */
        if (left == 0)
            rb->offset = align;
        else if (align != 0 && left >= SSL3_RT_HEADER_LENGTH) {
            /*
             * check if next packet length is large enough to justify payload
             * alignment...
             */
            pkt = rb->buf + rb->offset;
            if (pkt[0] == SSL3_RT_APPLICATION_DATA
                && (pkt[3] << 8 | pkt[4]) >= 128) {
                /*
                 * Note that even if packet is corrupted and its length field
                 * is insane, we can only be led to wrong decision about
                 * whether memmove will occur or not. Header values has no
                 * effect on memmove arguments and therefore no buffer
                 * overrun can be triggered.
                 */
                memmove(rb->buf + align, pkt, left);
                rb->offset = align;
            }
        }
        s->packet = rb->buf + rb->offset;
        s->packet_length = 0;
        /* ... now we can act as if 'extend' was set */
    }

    /*
     * For DTLS/UDP reads should not span multiple packets because the read
     * operation returns the whole packet at once (as long as it fits into
     * the buffer).
     */
    if (SSL_IS_DTLS(s)) {
        if (left == 0 && extend)
            return 0;
        if (left > 0 && n > left)
            n = left;
    }

    /* if there is enough in the buffer from a previous read, take some */
    if (left >= n) {
        s->packet_length += n;
        rb->left = left - n;
        rb->offset += n;
        return (n);
    }

    /* else we need to read more data */

    len = s->packet_length;
    pkt = rb->buf + align;
    /*
     * Move any available bytes to front of buffer: 'len' bytes already
     * pointed to by 'packet', 'left' extra ones at the end
     */
    if (s->packet != pkt) {     /* len > 0 */
        memmove(pkt, s->packet, len + left);
        s->packet = pkt;
        rb->offset = len + align;
    }

    if (n > (int)(rb->len - rb->offset)) { /* does not happen */
        SSLerr(SSL_F_SSL3_READ_N, ERR_R_INTERNAL_ERROR);
        return -1;
    }

    /* We always act like read_ahead is set for DTLS */
    if (!s->read_ahead && !SSL_IS_DTLS(s))
        /* ignore max parameter */
        max = n;
    else {
        if (max < n)
            max = n;
        if (max > (int)(rb->len - rb->offset))
            max = rb->len - rb->offset;
    }

    while (left < n) {
        /*
         * Now we have len+left bytes at the front of s->s3->rbuf.buf and
         * need to read in more until we have len+n (up to len+max if
         * possible)
         */

        clear_sys_error();
        if (s->rbio != NULL) {
            s->rwstate = SSL_READING;
            i = BIO_read(s->rbio, pkt + len + left, max - left);
        } else {
            SSLerr(SSL_F_SSL3_READ_N, SSL_R_READ_BIO_NOT_SET);
            i = -1;
        }

        if (i <= 0) {
            rb->left = left;
            if (s->mode & SSL_MODE_RELEASE_BUFFERS && !SSL_IS_DTLS(s))
                if (len + left == 0)
                    ssl3_release_read_buffer(s);
            return (i);
        }
        left += i;
        /*
         * reads should *never* span multiple packets for DTLS because the
         * underlying transport protocol is message oriented as opposed to
         * byte oriented as in the TLS case.
         */
        if (SSL_IS_DTLS(s)) {
            if (n > left)
                n = left;       /* makes the while condition false */
        }
    }

    /* done reading, now the book-keeping */
    rb->offset += n;
    rb->left = left - n;
    s->packet_length += n;
    s->rwstate = SSL_NOTHING;
    return (n);
}

Project: openssl

int ssl3_send_alert(SSL *s, int level, int desc)
{
    /* Map tls/ssl alert value to correct one */
    desc = s->method->ssl3_enc->alert_value(desc);
    if (s->version == SSL3_VERSION && desc == SSL_AD_PROTOCOL_VERSION)
        desc = SSL_AD_HANDSHAKE_FAILURE; /* SSL 3.0 does not have
                                          * protocol_version alerts */
    if (desc < 0)
        return -1;
    /* If a fatal one, remove from cache */
    if ((level == 2) && (s->session != NULL))
        SSL_CTX_remove_session(s->ctx, s->session);

    s->s3->alert_dispatch = 1;
    s->s3->send_alert[0] = level;
    s->s3->send_alert[1] = desc;
    if (s->s3->wbuf.left == 0)  /* data still being written out? */
        return s->method->ssl_dispatch_alert(s);
    /*
     * else data is still being written out, we will get written some time in
     * the future
     */
    return -1;
}

Project: openssl

int ssl3_write_pending(SSL *s, int type, const unsigned char *buf,
                       unsigned int len)
{
    int i;
    SSL3_BUFFER *wb = &(s->s3->wbuf);

/* XXXX */
    if ((s->s3->wpend_tot > (int)len)
        || ((s->s3->wpend_buf != buf) &&
            !(s->mode & SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER))
        || (s->s3->wpend_type != type)) {
        SSLerr(SSL_F_SSL3_WRITE_PENDING, SSL_R_BAD_WRITE_RETRY);
        return (-1);
    }

    for (;;) {
        clear_sys_error();
        if (s->wbio != NULL) {
            s->rwstate = SSL_WRITING;
            i = BIO_write(s->wbio,
                          (char *)&(wb->buf[wb->offset]),
                          (unsigned int)wb->left);
        } else {
            SSLerr(SSL_F_SSL3_WRITE_PENDING, SSL_R_BIO_NOT_SET);
            i = -1;
        }
        if (i == wb->left) {
            wb->left = 0;
            wb->offset += i;
            s->rwstate = SSL_NOTHING;
            return (s->s3->wpend_ret);
        } else if (i <= 0) {
            if (s->version == DTLS1_VERSION || s->version == DTLS1_BAD_VER) {
                /*
                 * For DTLS, just drop it. That's kind of the whole point in
                 * using a datagram service
                 */
                wb->left = 0;
            }
            return (i);
        }
        wb->offset += i;
        wb->left -= i;
    }
}