/* ssl/s23_srvr.c */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */
/* ====================================================================
 * Copyright (c) 1998-2006 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    openssl-core@openssl.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */

#include <stdio.h>
#include "ssl_locl.h"
#include <openssl/buffer.h>
#include <openssl/rand.h>
#include <openssl/objects.h>
#include <openssl/evp.h>
#ifdef OPENSSL_FIPS
# include <openssl/fips.h>
#endif

static const SSL_METHOD *ssl23_get_server_method(int ver);
int ssl23_get_client_hello(SSL *s);
static const SSL_METHOD *ssl23_get_server_method(int ver)
{
#ifndef OPENSSL_NO_SSL2
    if (ver == SSL2_VERSION)
        return (SSLv2_server_method());
#endif
#ifndef OPENSSL_NO_SSL3
    if (ver == SSL3_VERSION)
        return (SSLv3_server_method());
#endif
    if (ver == TLS1_VERSION)
        return (TLSv1_server_method());
    else if (ver == TLS1_1_VERSION)
        return (TLSv1_1_server_method());
    else if (ver == TLS1_2_VERSION)
        return (TLSv1_2_server_method());
    else
        return (NULL);
}

IMPLEMENT_ssl23_meth_func(SSLv23_server_method,
                          ssl23_accept,
                          ssl_undefined_function, ssl23_get_server_method)

int ssl23_accept(SSL *s)
{
    BUF_MEM *buf;
    unsigned long Time = (unsigned long)time(NULL);
    void (*cb) (const SSL *ssl, int type, int val) = NULL;
    int ret = -1;
    int new_state, state;

    RAND_add(&Time, sizeof(Time), 0);
    ERR_clear_error();
    clear_sys_error();

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

    s->in_handshake++;
    if (!SSL_in_init(s) || SSL_in_before(s))
        SSL_clear(s);

    for (;;) {
        state = s->state;

        switch (s->state) {
        case SSL_ST_BEFORE:
        case SSL_ST_ACCEPT:
        case SSL_ST_BEFORE | SSL_ST_ACCEPT:
        case SSL_ST_OK | SSL_ST_ACCEPT:

            s->server = 1;
            if (cb != NULL)
                cb(s, SSL_CB_HANDSHAKE_START, 1);

            /* s->version=SSL3_VERSION; */
            s->type = SSL_ST_ACCEPT;

            if (s->init_buf == NULL) {
                if ((buf = BUF_MEM_new()) == NULL) {
                    ret = -1;
                    goto end;
                }
                if (!BUF_MEM_grow(buf, SSL3_RT_MAX_PLAIN_LENGTH)) {
                    BUF_MEM_free(buf);
                    ret = -1;
                    goto end;
                }
                s->init_buf = buf;
            }

            ssl3_init_finished_mac(s);

            s->state = SSL23_ST_SR_CLNT_HELLO_A;
            s->ctx->stats.sess_accept++;
            s->init_num = 0;
            break;

        case SSL23_ST_SR_CLNT_HELLO_A:
        case SSL23_ST_SR_CLNT_HELLO_B:

            s->shutdown = 0;
            ret = ssl23_get_client_hello(s);
            if (ret >= 0)
                cb = NULL;
            goto end;
            /* break; */

        default:
            SSLerr(SSL_F_SSL23_ACCEPT, SSL_R_UNKNOWN_STATE);
            ret = -1;
            goto end;
            /* break; */
        }

        if ((cb != NULL) && (s->state != state)) {
            new_state = s->state;
            s->state = state;
            cb(s, SSL_CB_ACCEPT_LOOP, 1);
            s->state = new_state;
        }
    }
 end:
    s->in_handshake--;
    if (cb != NULL)
        cb(s, SSL_CB_ACCEPT_EXIT, ret);
    return (ret);
}

int ssl23_get_client_hello(SSL *s)
{
    /*-
     * Request this many bytes in initial read.
     * We can detect SSL 3.0/TLS 1.0 Client Hellos
     * ('type == 3') correctly only when the following
     * is in a single record, which is not guaranteed by
     * the protocol specification:
     * Byte  Content
     *  0     type            \
     *  1/2   version          > record header
     *  3/4   length          /
     *  5     msg_type        \
     *  6-8   length           > Client Hello message
     *  9/10  client_version  /
     */
    char buf_space[11];
    char *buf = &(buf_space[0]);
    unsigned char *p, *d, *d_len, *dd;
    unsigned int i;
    unsigned int csl, sil, cl;
    int n = 0, j;
    int type = 0;
    int v[2];

    if (s->state == SSL23_ST_SR_CLNT_HELLO_A) {
        /* read the initial header */
        v[0] = v[1] = 0;

        if (!ssl3_setup_buffers(s))
            goto err;

        n = ssl23_read_bytes(s, sizeof buf_space);
        if (n != sizeof buf_space)
            return (n);         /* n == -1 || n == 0 */

        p = s->packet;

        memcpy(buf, p, n);

        if ((p[0] & 0x80) && (p[2] == SSL2_MT_CLIENT_HELLO)) {
            /*
             * SSLv2 header
             */
            if ((p[3] == 0x00) && (p[4] == 0x02)) {
                v[0] = p[3];
                v[1] = p[4];
                /* SSLv2 */
                if (!(s->options & SSL_OP_NO_SSLv2))
                    type = 1;
            } else if (p[3] == SSL3_VERSION_MAJOR) {
                v[0] = p[3];
                v[1] = p[4];
                /* SSLv3/TLSv1 */
                if (p[4] >= TLS1_VERSION_MINOR) {
                    if (p[4] >= TLS1_2_VERSION_MINOR &&
                        !(s->options & SSL_OP_NO_TLSv1_2)) {
                        s->version = TLS1_2_VERSION;
                        s->state = SSL23_ST_SR_CLNT_HELLO_B;
                    } else if (p[4] >= TLS1_1_VERSION_MINOR &&
                               !(s->options & SSL_OP_NO_TLSv1_1)) {
                        s->version = TLS1_1_VERSION;
                        /*
                         * type=2;
                         *//*
                         * done later to survive restarts
                         */
                        s->state = SSL23_ST_SR_CLNT_HELLO_B;
                    } else if (!(s->options & SSL_OP_NO_TLSv1)) {
                        s->version = TLS1_VERSION;
                        /*
                         * type=2;
                         *//*
                         * done later to survive restarts
                         */
                        s->state = SSL23_ST_SR_CLNT_HELLO_B;
                    } else if (!(s->options & SSL_OP_NO_SSLv3)) {
                        s->version = SSL3_VERSION;
                        /* type=2; */
                        s->state = SSL23_ST_SR_CLNT_HELLO_B;
                    } else if (!(s->options & SSL_OP_NO_SSLv2)) {
                        type = 1;
                    }
                } else if (!(s->options & SSL_OP_NO_SSLv3)) {
                    s->version = SSL3_VERSION;
                    /* type=2; */
                    s->state = SSL23_ST_SR_CLNT_HELLO_B;
                } else if (!(s->options & SSL_OP_NO_SSLv2))
                    type = 1;

            }
        }
        /* p[4] < 5 ... silly record length? */
        else if ((p[0] == SSL3_RT_HANDSHAKE) &&
                 (p[1] == SSL3_VERSION_MAJOR) &&
                 (p[5] == SSL3_MT_CLIENT_HELLO) && ((p[3] == 0 && p[4] < 5)
                                                    || (p[9] >= p[1]))) {
            /*
             * SSLv3 or tls1 header
             */

            v[0] = p[1];        /* major version (= SSL3_VERSION_MAJOR) */
            /*
             * We must look at client_version inside the Client Hello message
             * to get the correct minor version. However if we have only a
             * pathologically small fragment of the Client Hello message, this
             * would be difficult, and we'd have to read more records to find
             * out. No known SSL 3.0 client fragments ClientHello like this,
             * so we simply reject such connections to avoid protocol version
             * downgrade attacks.
             */
            if (p[3] == 0 && p[4] < 6) {
                SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO, SSL_R_RECORD_TOO_SMALL);
                goto err;
            }
            /*
             * if major version number > 3 set minor to a value which will
             * use the highest version 3 we support. If TLS 2.0 ever appears
             * we will need to revise this....
             */
            if (p[9] > SSL3_VERSION_MAJOR)
                v[1] = 0xff;
            else
                v[1] = p[10];   /* minor version according to client_version */
            if (v[1] >= TLS1_VERSION_MINOR) {
                if (v[1] >= TLS1_2_VERSION_MINOR &&
                    !(s->options & SSL_OP_NO_TLSv1_2)) {
                    s->version = TLS1_2_VERSION;
                    type = 3;
                } else if (v[1] >= TLS1_1_VERSION_MINOR &&
                           !(s->options & SSL_OP_NO_TLSv1_1)) {
                    s->version = TLS1_1_VERSION;
                    type = 3;
                } else if (!(s->options & SSL_OP_NO_TLSv1)) {
                    s->version = TLS1_VERSION;
                    type = 3;
                } else if (!(s->options & SSL_OP_NO_SSLv3)) {
                    s->version = SSL3_VERSION;
                    type = 3;
                }
            } else {
                /* client requests SSL 3.0 */
                if (!(s->options & SSL_OP_NO_SSLv3)) {
                    s->version = SSL3_VERSION;
                    type = 3;
                } else if (!(s->options & SSL_OP_NO_TLSv1)) {
                    /*
                     * we won't be able to use TLS of course, but this will
                     * send an appropriate alert
                     */
                    s->version = TLS1_VERSION;
                    type = 3;
                }
            }
        } else if ((strncmp("GET ", (char *)p, 4) == 0) ||
                   (strncmp("POST ", (char *)p, 5) == 0) ||
                   (strncmp("HEAD ", (char *)p, 5) == 0) ||
                   (strncmp("PUT ", (char *)p, 4) == 0)) {
            SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO, SSL_R_HTTP_REQUEST);
            goto err;
        } else if (strncmp("CONNECT", (char *)p, 7) == 0) {
            SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO, SSL_R_HTTPS_PROXY_REQUEST);
            goto err;
        }
    }

    /* ensure that TLS_MAX_VERSION is up-to-date */
    OPENSSL_assert(s->version <= TLS_MAX_VERSION);

#ifdef OPENSSL_FIPS
    if (FIPS_mode() && (s->version < TLS1_VERSION)) {
        SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO,
               SSL_R_ONLY_TLS_ALLOWED_IN_FIPS_MODE);
        goto err;
    }
#endif

    if (s->state == SSL23_ST_SR_CLNT_HELLO_B) {
        /*
         * we have SSLv3/TLSv1 in an SSLv2 header (other cases skip this
         * state)
         */

        type = 2;
        p = s->packet;
        v[0] = p[3];            /* == SSL3_VERSION_MAJOR */
        v[1] = p[4];

        /*-
         * An SSLv3/TLSv1 backwards-compatible CLIENT-HELLO in an SSLv2
         * header is sent directly on the wire, not wrapped as a TLS
         * record. It's format is:
         * Byte  Content
         * 0-1   msg_length
         * 2     msg_type
         * 3-4   version
         * 5-6   cipher_spec_length
         * 7-8   session_id_length
         * 9-10  challenge_length
         * ...   ...
         */
        n = ((p[0] & 0x7f) << 8) | p[1];
        if (n > (1024 * 4)) {
            SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO, SSL_R_RECORD_TOO_LARGE);
            goto err;
        }
        if (n < 9) {
            SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO,
                   SSL_R_RECORD_LENGTH_MISMATCH);
            goto err;
        }

        j = ssl23_read_bytes(s, n + 2);
        /*
         * We previously read 11 bytes, so if j > 0, we must have j == n+2 ==
         * s->packet_length. We have at least 11 valid packet bytes.
         */
        if (j <= 0)
            return (j);

        ssl3_finish_mac(s, s->packet + 2, s->packet_length - 2);

        /* CLIENT-HELLO */
        if (s->msg_callback)
            s->msg_callback(0, SSL2_VERSION, 0, s->packet + 2,
                            s->packet_length - 2, s, s->msg_callback_arg);

        p = s->packet;
        p += 5;
        n2s(p, csl);
        n2s(p, sil);
        n2s(p, cl);
        d = (unsigned char *)s->init_buf->data;
        if ((csl + sil + cl + 11) != s->packet_length) { /* We can't have TLS
                                                          * extensions in SSL
                                                          * 2.0 format *
                                                          * Client Hello, can
                                                          * we? Error
                                                          * condition should
                                                          * be * '>'
                                                          * otherweise */
            SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO,
                   SSL_R_RECORD_LENGTH_MISMATCH);
            goto err;
        }

        /* record header: msg_type ... */
        *(d++) = SSL3_MT_CLIENT_HELLO;
        /* ... and length (actual value will be written later) */
        d_len = d;
        d += 3;

        /* client_version */
        *(d++) = SSL3_VERSION_MAJOR; /* == v[0] */
        *(d++) = v[1];

        /* lets populate the random area */
        /* get the challenge_length */
        i = (cl > SSL3_RANDOM_SIZE) ? SSL3_RANDOM_SIZE : cl;
        memset(d, 0, SSL3_RANDOM_SIZE);
        memcpy(&(d[SSL3_RANDOM_SIZE - i]), &(p[csl + sil]), i);
        d += SSL3_RANDOM_SIZE;

        /* no session-id reuse */
        *(d++) = 0;

        /* ciphers */
        j = 0;
        dd = d;
        d += 2;
        for (i = 0; i < csl; i += 3) {
            if (p[i] != 0)
                continue;
            *(d++) = p[i + 1];
            *(d++) = p[i + 2];
            j += 2;
        }
        s2n(j, dd);

        /* COMPRESSION */
        *(d++) = 1;
        *(d++) = 0;

#if 0
        /* copy any remaining data with may be extensions */
        p = p + csl + sil + cl;
        while (p < s->packet + s->packet_length) {
            *(d++) = *(p++);
        }
#endif

        i = (d - (unsigned char *)s->init_buf->data) - 4;
        l2n3((long)i, d_len);

        /* get the data reused from the init_buf */
        s->s3->tmp.reuse_message = 1;
        s->s3->tmp.message_type = SSL3_MT_CLIENT_HELLO;
        s->s3->tmp.message_size = i;
    }

    /* imaginary new state (for program structure): */
    /* s->state = SSL23_SR_CLNT_HELLO_C */

    if (type == 1) {
#ifdef OPENSSL_NO_SSL2
        SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO, SSL_R_UNSUPPORTED_PROTOCOL);
        goto err;
#else
        /* we are talking sslv2 */
        /*
         * we need to clean up the SSLv3/TLSv1 setup and put in the sslv2
         * stuff.
         */

        if (s->s2 == NULL) {
            if (!ssl2_new(s))
                goto err;
        } else
            ssl2_clear(s);

        if (s->s3 != NULL)
            ssl3_free(s);

        if (!BUF_MEM_grow_clean(s->init_buf,
                                SSL2_MAX_RECORD_LENGTH_3_BYTE_HEADER)) {
            goto err;
        }

        s->state = SSL2_ST_GET_CLIENT_HELLO_A;
        if (s->options & SSL_OP_NO_TLSv1 && s->options & SSL_OP_NO_SSLv3)
            s->s2->ssl2_rollback = 0;
        else
            /*
             * reject SSL 2.0 session if client supports SSL 3.0 or TLS 1.0
             * (SSL 3.0 draft/RFC 2246, App. E.2)
             */
            s->s2->ssl2_rollback = 1;

        /*
         * setup the n bytes we have read so we get them from the sslv2
         * buffer
         */
        s->rstate = SSL_ST_READ_HEADER;
        s->packet_length = n;
        s->packet = &(s->s2->rbuf[0]);
        memcpy(s->packet, buf, n);
        s->s2->rbuf_left = n;
        s->s2->rbuf_offs = 0;

        s->method = SSLv2_server_method();
        s->handshake_func = s->method->ssl_accept;
#endif
    }

    if ((type == 2) || (type == 3)) {
        /*
         * we have SSLv3/TLSv1 (type 2: SSL2 style, type 3: SSL3/TLS style)
         */
        const SSL_METHOD *new_method;
        new_method = ssl23_get_server_method(s->version);
        if (new_method == NULL) {
            SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO, SSL_R_UNSUPPORTED_PROTOCOL);
            goto err;
        }
        s->method = new_method;

        if (!ssl_init_wbio_buffer(s, 1))
            goto err;

        /* we are in this state */
        s->state = SSL3_ST_SR_CLNT_HELLO_A;

        if (type == 3) {
            /*
             * put the 'n' bytes we have read into the input buffer for SSLv3
             */
            s->rstate = SSL_ST_READ_HEADER;
            s->packet_length = n;
            if (s->s3->rbuf.buf == NULL)
                if (!ssl3_setup_read_buffer(s))
                    goto err;

            s->packet = &(s->s3->rbuf.buf[0]);
            memcpy(s->packet, buf, n);
            s->s3->rbuf.left = n;
            s->s3->rbuf.offset = 0;
        } else {
            s->packet_length = 0;
            s->s3->rbuf.left = 0;
            s->s3->rbuf.offset = 0;
        }
#if 0                           /* ssl3_get_client_hello does this */
        s->client_version = (v[0] << 8) | v[1];
#endif
        s->handshake_func = s->method->ssl_accept;
    }

    if ((type < 1) || (type > 3)) {
        /* bad, very bad */
        SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO, SSL_R_UNKNOWN_PROTOCOL);
        goto err;
    }
    s->init_num = 0;

    if (buf != buf_space)
        OPENSSL_free(buf);
    return (SSL_accept(s));
 err:
    if (buf != buf_space)
        OPENSSL_free(buf);
    return (-1);
}
