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s23_srvr.c

/* 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) 1998-2001 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>

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

SSL_METHOD *SSLv23_server_method(void)
      {
      static int init=1;
      static SSL_METHOD SSLv23_server_data;

      if (init)
            {
            CRYPTO_w_lock(CRYPTO_LOCK_SSL_METHOD);

            if (init)
                  {
                  memcpy((char *)&SSLv23_server_data,
                        (char *)sslv23_base_method(),sizeof(SSL_METHOD));
                  SSLv23_server_data.ssl_accept=ssl23_accept;
                  SSLv23_server_data.get_ssl_method=ssl23_get_server_method;
                  init=0;
                  }

            CRYPTO_w_unlock(CRYPTO_LOCK_SSL_METHOD);
            }
      return(&SSLv23_server_data);
      }

int ssl23_accept(SSL *s)
      {
      BUF_MEM *buf;
      unsigned long Time=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))
                              {
                              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)
      {
      char buf_space[11]; /* 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= &(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];
#ifndef OPENSSL_NO_RSA
      int use_sslv2_strong=0;
#endif

      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 (!(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;

                        }
                  }
            else if ((p[0] == SSL3_RT_HANDSHAKE) &&
                   (p[1] == SSL3_VERSION_MAJOR) &&
                   (p[5] == SSL3_MT_CLIENT_HELLO) &&
                   ((p[3] == 0 && p[4] < 5 /* silly record length? */)
                        || (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 assume TLS 1.0 to avoid protocol version downgrade
                   * attacks. */
                  if (p[3] == 0 && p[4] < 6)
                        {
#if 0
                        SSLerr(SSL_F_SSL23_GET_CLIENT_HELLO,SSL_R_RECORD_TOO_SMALL);
                        goto err;
#else
                        v[1] = TLS1_VERSION_MINOR;
#endif
                        }
                  else
                        v[1]=p[10]; /* minor version according to client_version */
                  if (v[1] >= TLS1_VERSION_MINOR)
                        {
                        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;
                  }
            }

      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];

            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;
                  }

            j=ssl23_read_bytes(s,n+2);
            if (j <= 0) return(j);

            ssl3_finish_mac(s, s->packet+2, s->packet_length-2);
            if (s->msg_callback)
                  s->msg_callback(0, SSL2_VERSION, 0, s->packet+2, s->packet_length-2, s, s->msg_callback_arg); /* CLIENT-HELLO */

            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)
                  {
                  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;
            
            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_MSIE_SSLV2_RSA_PADDING) ||
                  use_sslv2_strong ||
                  (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) */

            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;
                  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 (s->version == TLS1_VERSION)
                  s->method = TLSv1_server_method();
            else
                  s->method = SSLv3_server_method();
#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);
      s->first_packet=1;
      return(SSL_accept(s));
err:
      if (buf != buf_space) OPENSSL_free(buf);
      return(-1);
      }

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