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[netbsd-mini2440.git] / crypto / external / bsd / openssl / dist / ssl / s3_both.c

/* ssl/s3_both.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) 1998-2002 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).
 *
 */
/* ====================================================================
 * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
 * ECC cipher suite support in OpenSSL originally developed by 
 * SUN MICROSYSTEMS, INC., and contributed to the OpenSSL project.
 */

#include <limits.h>
#include <string.h>
#include <stdio.h>
#include "ssl_locl.h"
#include <openssl/buffer.h>
#include <openssl/rand.h>
#include <openssl/objects.h>
#include <openssl/evp.h>
#include <openssl/x509.h>

/* send s->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or SSL3_RT_CHANGE_CIPHER_SPEC) */
int ssl3_do_write(SSL *s, int type)
        {
        int ret;

        ret=ssl3_write_bytes(s,type,&s->init_buf->data[s->init_off],
                             s->init_num);
        if (ret < 0) return(-1);
        if (type == SSL3_RT_HANDSHAKE)
                /* should not be done for 'Hello Request's, but in that case
                 * we'll ignore the result anyway */
                ssl3_finish_mac(s,(unsigned char *)&s->init_buf->data[s->init_off],ret);
        
        if (ret == s->init_num)
                {
                if (s->msg_callback)
                        s->msg_callback(1, s->version, type, s->init_buf->data, (size_t)(s->init_off + s->init_num), s, s->msg_callback_arg);
                return(1);
                }
        s->init_off+=ret;
        s->init_num-=ret;
        return(0);
        }

int ssl3_send_finished(SSL *s, int a, int b, const char *sender, int slen)
        {
        unsigned char *p,*d;
        int i;
        unsigned long l;

        if (s->state == a)
                {
                d=(unsigned char *)s->init_buf->data;
                p= &(d[4]);

                i=s->method->ssl3_enc->final_finish_mac(s,
                        sender,slen,s->s3->tmp.finish_md);
                s->s3->tmp.finish_md_len = i;
                memcpy(p, s->s3->tmp.finish_md, i);
                p+=i;
                l=i;

                /* Copy the finished so we can use it for
                   renegotiation checks */
                if(s->type == SSL_ST_CONNECT)
                        {
                         OPENSSL_assert(i <= EVP_MAX_MD_SIZE);
                         memcpy(s->s3->previous_client_finished, 
                             s->s3->tmp.finish_md, i);
                         s->s3->previous_client_finished_len=i;
                        }
                else
                        {
                        OPENSSL_assert(i <= EVP_MAX_MD_SIZE);
                        memcpy(s->s3->previous_server_finished, 
                            s->s3->tmp.finish_md, i);
                        s->s3->previous_server_finished_len=i;
                        }

#ifdef OPENSSL_SYS_WIN16
                /* MSVC 1.5 does not clear the top bytes of the word unless
                 * I do this.
                 */
                l&=0xffff;
#endif

                *(d++)=SSL3_MT_FINISHED;
                l2n3(l,d);
                s->init_num=(int)l+4;
                s->init_off=0;

                s->state=b;
                }

        /* SSL3_ST_SEND_xxxxxx_HELLO_B */
        return(ssl3_do_write(s,SSL3_RT_HANDSHAKE));
        }

int ssl3_get_finished(SSL *s, int a, int b)
        {
        int al,i,ok;
        long n;
        unsigned char *p;

        /* the mac has already been generated when we received the
         * change cipher spec message and is in s->s3->tmp.peer_finish_md
         */ 

        n=s->method->ssl_get_message(s,
                a,
                b,
                SSL3_MT_FINISHED,
                64, /* should actually be 36+4 :-) */
                &ok);

        if (!ok) return((int)n);

        /* If this occurs, we have missed a message */
        if (!s->s3->change_cipher_spec)
                {
                al=SSL_AD_UNEXPECTED_MESSAGE;
                SSLerr(SSL_F_SSL3_GET_FINISHED,SSL_R_GOT_A_FIN_BEFORE_A_CCS);
                goto f_err;
                }
        s->s3->change_cipher_spec=0;

        p = (unsigned char *)s->init_msg;
        i = s->s3->tmp.peer_finish_md_len;

        if (i != n)
                {
                al=SSL_AD_DECODE_ERROR;
                SSLerr(SSL_F_SSL3_GET_FINISHED,SSL_R_BAD_DIGEST_LENGTH);
                goto f_err;
                }

        if (memcmp(p, s->s3->tmp.peer_finish_md, i) != 0)
                {
                al=SSL_AD_DECRYPT_ERROR;
                SSLerr(SSL_F_SSL3_GET_FINISHED,SSL_R_DIGEST_CHECK_FAILED);
                goto f_err;
                }

        /* Copy the finished so we can use it for
           renegotiation checks */
        if(s->type == SSL_ST_ACCEPT)
                {
                OPENSSL_assert(i <= EVP_MAX_MD_SIZE);
                memcpy(s->s3->previous_client_finished, 
                    s->s3->tmp.peer_finish_md, i);
                s->s3->previous_client_finished_len=i;
                }
        else
                {
                OPENSSL_assert(i <= EVP_MAX_MD_SIZE);
                memcpy(s->s3->previous_server_finished, 
                    s->s3->tmp.peer_finish_md, i);
                s->s3->previous_server_finished_len=i;
                }

        return(1);
f_err:
        ssl3_send_alert(s,SSL3_AL_FATAL,al);
        return(0);
        }

/* for these 2 messages, we need to
 * ssl->enc_read_ctx                    re-init
 * ssl->s3->read_sequence               zero
 * ssl->s3->read_mac_secret             re-init
 * ssl->session->read_sym_enc           assign
 * ssl->session->read_compression       assign
 * ssl->session->read_hash              assign
 */
int ssl3_send_change_cipher_spec(SSL *s, int a, int b)
        { 
        unsigned char *p;

        if (s->state == a)
                {
                p=(unsigned char *)s->init_buf->data;
                *p=SSL3_MT_CCS;
                s->init_num=1;
                s->init_off=0;

                s->state=b;
                }

        /* SSL3_ST_CW_CHANGE_B */
        return(ssl3_do_write(s,SSL3_RT_CHANGE_CIPHER_SPEC));
        }

static int ssl3_add_cert_to_buf(BUF_MEM *buf, unsigned long *l, X509 *x)
        {
        int n;
        unsigned char *p;

        n=i2d_X509(x,NULL);
        if (!BUF_MEM_grow_clean(buf,(int)(n+(*l)+3)))
                {
                SSLerr(SSL_F_SSL3_ADD_CERT_TO_BUF,ERR_R_BUF_LIB);
                return(-1);
                }
        p=(unsigned char *)&(buf->data[*l]);
        l2n3(n,p);
        i2d_X509(x,&p);
        *l+=n+3;

        return(0);
        }

unsigned long ssl3_output_cert_chain(SSL *s, X509 *x)
        {
        unsigned char *p;
        int i;
        unsigned long l=7;
        BUF_MEM *buf;
        int no_chain;

        if ((s->mode & SSL_MODE_NO_AUTO_CHAIN) || s->ctx->extra_certs)
                no_chain = 1;
        else
                no_chain = 0;

        /* TLSv1 sends a chain with nothing in it, instead of an alert */
        buf=s->init_buf;
        if (!BUF_MEM_grow_clean(buf,10))
                {
                SSLerr(SSL_F_SSL3_OUTPUT_CERT_CHAIN,ERR_R_BUF_LIB);
                return(0);
                }
        if (x != NULL)
                {
                if (no_chain)
                        {
                        if (ssl3_add_cert_to_buf(buf, &l, x))
                                return(0);
                        }
                else
                        {
                        X509_STORE_CTX xs_ctx;

                        if (!X509_STORE_CTX_init(&xs_ctx,s->ctx->cert_store,x,NULL))
                                {
                                SSLerr(SSL_F_SSL3_OUTPUT_CERT_CHAIN,ERR_R_X509_LIB);
                                return(0);
                                }
                        X509_verify_cert(&xs_ctx);
                        for (i=0; i < sk_X509_num(xs_ctx.chain); i++)
                                {
                                x = sk_X509_value(xs_ctx.chain, i);

                                if (ssl3_add_cert_to_buf(buf, &l, x))
                                        {
                                        X509_STORE_CTX_cleanup(&xs_ctx);
                                        return 0;
                                        }
                                }
                        X509_STORE_CTX_cleanup(&xs_ctx);
                        }
                }
        /* Thawte special :-) */
        for (i=0; i<sk_X509_num(s->ctx->extra_certs); i++)
                {
                x=sk_X509_value(s->ctx->extra_certs,i);
                if (ssl3_add_cert_to_buf(buf, &l, x))
                        return(0);
                }

        l-=7;
        p=(unsigned char *)&(buf->data[4]);
        l2n3(l,p);
        l+=3;
        p=(unsigned char *)&(buf->data[0]);
        *(p++)=SSL3_MT_CERTIFICATE;
        l2n3(l,p);
        l+=4;
        return(l);
        }

/* Obtain handshake message of message type 'mt' (any if mt == -1),
 * maximum acceptable body length 'max'.
 * The first four bytes (msg_type and length) are read in state 'st1',
 * the body is read in state 'stn'.
 */
long ssl3_get_message(SSL *s, int st1, int stn, int mt, long max, int *ok)
        {
        unsigned char *p;
        unsigned long l;
        long n;
        int i,al;

        if (s->s3->tmp.reuse_message)
                {
                s->s3->tmp.reuse_message=0;
                if ((mt >= 0) && (s->s3->tmp.message_type != mt))
                        {
                        al=SSL_AD_UNEXPECTED_MESSAGE;
                        SSLerr(SSL_F_SSL3_GET_MESSAGE,SSL_R_UNEXPECTED_MESSAGE);
                        goto f_err;
                        }
                *ok=1;
                s->init_msg = s->init_buf->data + 4;
                s->init_num = (int)s->s3->tmp.message_size;
                return s->init_num;
                }

        p=(unsigned char *)s->init_buf->data;

        if (s->state == st1) /* s->init_num < 4 */
                {
                int skip_message;

                do
                        {
                        while (s->init_num < 4)
                                {
                                i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
                                        &p[s->init_num],4 - s->init_num, 0);
                                if (i <= 0)
                                        {
                                        s->rwstate=SSL_READING;
                                        *ok = 0;
                                        return i;
                                        }
                                s->init_num+=i;
                                }
                        
                        skip_message = 0;
                        if (!s->server)
                                if (p[0] == SSL3_MT_HELLO_REQUEST)
                                        /* The server may always send 'Hello Request' messages --
                                         * we are doing a handshake anyway now, so ignore them
                                         * if their format is correct. Does not count for
                                         * 'Finished' MAC. */
                                        if (p[1] == 0 && p[2] == 0 &&p[3] == 0)
                                                {
                                                s->init_num = 0;
                                                skip_message = 1;

                                                if (s->msg_callback)
                                                        s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, p, 4, s, s->msg_callback_arg);
                                                }
                        }
                while (skip_message);

                /* s->init_num == 4 */

                if ((mt >= 0) && (*p != mt))
                        {
                        al=SSL_AD_UNEXPECTED_MESSAGE;
                        SSLerr(SSL_F_SSL3_GET_MESSAGE,SSL_R_UNEXPECTED_MESSAGE);
                        goto f_err;
                        }
                if ((mt < 0) && (*p == SSL3_MT_CLIENT_HELLO) &&
                                        (st1 == SSL3_ST_SR_CERT_A) &&
                                        (stn == SSL3_ST_SR_CERT_B))
                        {
                        /* At this point we have got an MS SGC second client
                         * hello (maybe we should always allow the client to
                         * start a new handshake?). We need to restart the mac.
                         * Don't increment {num,total}_renegotiations because
                         * we have not completed the handshake. */
                        ssl3_init_finished_mac(s);
                        }

                s->s3->tmp.message_type= *(p++);

                n2l3(p,l);
                if (l > (unsigned long)max)
                        {
                        al=SSL_AD_ILLEGAL_PARAMETER;
                        SSLerr(SSL_F_SSL3_GET_MESSAGE,SSL_R_EXCESSIVE_MESSAGE_SIZE);
                        goto f_err;
                        }
                if (l > (INT_MAX-4)) /* BUF_MEM_grow takes an 'int' parameter */
                        {
                        al=SSL_AD_ILLEGAL_PARAMETER;
                        SSLerr(SSL_F_SSL3_GET_MESSAGE,SSL_R_EXCESSIVE_MESSAGE_SIZE);
                        goto f_err;
                        }
                if (l && !BUF_MEM_grow_clean(s->init_buf,(int)l+4))
                        {
                        SSLerr(SSL_F_SSL3_GET_MESSAGE,ERR_R_BUF_LIB);
                        goto err;
                        }
                s->s3->tmp.message_size=l;
                s->state=stn;

                s->init_msg = s->init_buf->data + 4;
                s->init_num = 0;
                }

        /* next state (stn) */
        p = s->init_msg;
        n = s->s3->tmp.message_size - s->init_num;
        while (n > 0)
                {
                i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,&p[s->init_num],n,0);
                if (i <= 0)
                        {
                        s->rwstate=SSL_READING;
                        *ok = 0;
                        return i;
                        }
                s->init_num += i;
                n -= i;
                }
        ssl3_finish_mac(s, (unsigned char *)s->init_buf->data, s->init_num + 4);
        if (s->msg_callback)
                s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, s->init_buf->data, (size_t)s->init_num + 4, s, s->msg_callback_arg);
        *ok=1;
        return s->init_num;
f_err:
        ssl3_send_alert(s,SSL3_AL_FATAL,al);
err:
        *ok=0;
        return(-1);
        }

int ssl_cert_type(X509 *x, EVP_PKEY *pkey)
        {
        EVP_PKEY *pk;
        int ret= -1,i;

        if (pkey == NULL)
                pk=X509_get_pubkey(x);
        else
                pk=pkey;
        if (pk == NULL) goto err;

        i=pk->type;
        if (i == EVP_PKEY_RSA)
                {
                ret=SSL_PKEY_RSA_ENC;
                }
        else if (i == EVP_PKEY_DSA)
                {
                ret=SSL_PKEY_DSA_SIGN;
                }
#ifndef OPENSSL_NO_EC
        else if (i == EVP_PKEY_EC)
                {
                ret = SSL_PKEY_ECC;
                }       
#endif
        else if (i == NID_id_GostR3410_94 || i == NID_id_GostR3410_94_cc) 
                {
                ret = SSL_PKEY_GOST94;
                }
        else if (i == NID_id_GostR3410_2001 || i == NID_id_GostR3410_2001_cc) 
                {
                ret = SSL_PKEY_GOST01;
                }
err:
        if(!pkey) EVP_PKEY_free(pk);
        return(ret);
        }

int ssl_verify_alarm_type(long type)
        {
        int al;

        switch(type)
                {
        case X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT:
        case X509_V_ERR_UNABLE_TO_GET_CRL:
        case X509_V_ERR_UNABLE_TO_GET_CRL_ISSUER:
                al=SSL_AD_UNKNOWN_CA;
                break;
        case X509_V_ERR_UNABLE_TO_DECRYPT_CERT_SIGNATURE:
        case X509_V_ERR_UNABLE_TO_DECRYPT_CRL_SIGNATURE:
        case X509_V_ERR_UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY:
        case X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD:
        case X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD:
        case X509_V_ERR_ERROR_IN_CRL_LAST_UPDATE_FIELD:
        case X509_V_ERR_ERROR_IN_CRL_NEXT_UPDATE_FIELD:
        case X509_V_ERR_CERT_NOT_YET_VALID:
        case X509_V_ERR_CRL_NOT_YET_VALID:
        case X509_V_ERR_CERT_UNTRUSTED:
        case X509_V_ERR_CERT_REJECTED:
                al=SSL_AD_BAD_CERTIFICATE;
                break;
        case X509_V_ERR_CERT_SIGNATURE_FAILURE:
        case X509_V_ERR_CRL_SIGNATURE_FAILURE:
                al=SSL_AD_DECRYPT_ERROR;
                break;
        case X509_V_ERR_CERT_HAS_EXPIRED:
        case X509_V_ERR_CRL_HAS_EXPIRED:
                al=SSL_AD_CERTIFICATE_EXPIRED;
                break;
        case X509_V_ERR_CERT_REVOKED:
                al=SSL_AD_CERTIFICATE_REVOKED;
                break;
        case X509_V_ERR_OUT_OF_MEM:
                al=SSL_AD_INTERNAL_ERROR;
                break;
        case X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT:
        case X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN:
        case X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY:
        case X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE:
        case X509_V_ERR_CERT_CHAIN_TOO_LONG:
        case X509_V_ERR_PATH_LENGTH_EXCEEDED:
        case X509_V_ERR_INVALID_CA:
                al=SSL_AD_UNKNOWN_CA;
                break;
        case X509_V_ERR_APPLICATION_VERIFICATION:
                al=SSL_AD_HANDSHAKE_FAILURE;
                break;
        case X509_V_ERR_INVALID_PURPOSE:
                al=SSL_AD_UNSUPPORTED_CERTIFICATE;
                break;
        default:
                al=SSL_AD_CERTIFICATE_UNKNOWN;
                break;
                }
        return(al);
        }

#ifndef OPENSSL_NO_BUF_FREELISTS
/* On some platforms, malloc() performance is bad enough that you can't just
 * free() and malloc() buffers all the time, so we need to use freelists from
 * unused buffers.  Currently, each freelist holds memory chunks of only a
 * given size (list->chunklen); other sized chunks are freed and malloced.
 * This doesn't help much if you're using many different SSL option settings
 * with a given context.  (The options affecting buffer size are
 * max_send_fragment, read buffer vs write buffer,
 * SSL_OP_MICROSOFT_BIG_WRITE_BUFFER, SSL_OP_NO_COMPRESSION, and
 * SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS.)  Using a separate freelist for every
 * possible size is not an option, since max_send_fragment can take on many
 * different values.
 *
 * If you are on a platform with a slow malloc(), and you're using SSL
 * connections with many different settings for these options, and you need to
 * use the SSL_MOD_RELEASE_BUFFERS feature, you have a few options:
 *    - Link against a faster malloc implementation.
 *    - Use a separate SSL_CTX for each option set.
 *    - Improve this code.
 */
static void *
freelist_extract(SSL_CTX *ctx, int for_read, int sz)
        {
        SSL3_BUF_FREELIST *list;
        SSL3_BUF_FREELIST_ENTRY *ent = NULL;
        void *result = NULL;

        CRYPTO_w_lock(CRYPTO_LOCK_SSL_CTX);
        list = for_read ? ctx->rbuf_freelist : ctx->wbuf_freelist;
        if (list != NULL && sz == (int)list->chunklen)
                ent = list->head;
        if (ent != NULL)
                {
                list->head = ent->next;
                result = ent;
                if (--list->len == 0)
                        list->chunklen = 0;
                }
        CRYPTO_w_unlock(CRYPTO_LOCK_SSL_CTX);
        if (!result)
                result = OPENSSL_malloc(sz);
        return result;
}

static void
freelist_insert(SSL_CTX *ctx, int for_read, size_t sz, void *mem)
        {
        SSL3_BUF_FREELIST *list;
        SSL3_BUF_FREELIST_ENTRY *ent;

        CRYPTO_w_lock(CRYPTO_LOCK_SSL_CTX);
        list = for_read ? ctx->rbuf_freelist : ctx->wbuf_freelist;
        if (list != NULL &&
            (sz == list->chunklen || list->chunklen == 0) &&
            list->len < ctx->freelist_max_len &&
            sz >= sizeof(*ent))
                {
                list->chunklen = sz;
                ent = mem;
                ent->next = list->head;
                list->head = ent;
                ++list->len;
                mem = NULL;
                }

        CRYPTO_w_unlock(CRYPTO_LOCK_SSL_CTX);
        if (mem)
                OPENSSL_free(mem);
        }
#else
#define freelist_extract(c,fr,sz) OPENSSL_malloc(sz)
#define freelist_insert(c,fr,sz,m) OPENSSL_free(m)
#endif

int ssl3_setup_read_buffer(SSL *s)
        {
        unsigned char *p;
        size_t len,align=0,headerlen;
        
        if (SSL_version(s) == DTLS1_VERSION || SSL_version(s) == DTLS1_BAD_VER)
                headerlen = DTLS1_RT_HEADER_LENGTH;
        else
                headerlen = SSL3_RT_HEADER_LENGTH;

#if defined(SSL3_ALIGN_PAYLOAD) && SSL3_ALIGN_PAYLOAD!=0
        align = (-SSL3_RT_HEADER_LENGTH)&(SSL3_ALIGN_PAYLOAD-1);
#endif

        if (s->s3->rbuf.buf == NULL)
                {
                len = SSL3_RT_MAX_PLAIN_LENGTH
                        + SSL3_RT_MAX_ENCRYPTED_OVERHEAD
                        + headerlen + align;
                if (s->options & SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER)
                        {
                        s->s3->init_extra = 1;
                        len += SSL3_RT_MAX_EXTRA;
                        }
#ifndef OPENSSL_NO_COMP
                if (!(s->options & SSL_OP_NO_COMPRESSION))
                        len += SSL3_RT_MAX_COMPRESSED_OVERHEAD;
#endif
                if ((p=freelist_extract(s->ctx, 1, len)) == NULL)
                        goto err;
                s->s3->rbuf.buf = p;
                s->s3->rbuf.len = len;
                }

        s->packet= &(s->s3->rbuf.buf[0]);
        return 1;

err:
        SSLerr(SSL_F_SSL3_SETUP_READ_BUFFER,ERR_R_MALLOC_FAILURE);
        return 0;
        }

int ssl3_setup_write_buffer(SSL *s)
        {
        unsigned char *p;
        size_t len,align=0,headerlen;

        if (SSL_version(s) == DTLS1_VERSION || SSL_version(s) == DTLS1_BAD_VER)
                headerlen = DTLS1_RT_HEADER_LENGTH + 1;
        else
                headerlen = SSL3_RT_HEADER_LENGTH;

#if defined(SSL3_ALIGN_PAYLOAD) && SSL3_ALIGN_PAYLOAD!=0
        align = (-SSL3_RT_HEADER_LENGTH)&(SSL3_ALIGN_PAYLOAD-1);
#endif

        if (s->s3->wbuf.buf == NULL)
                {
                len = s->max_send_fragment
                        + SSL3_RT_SEND_MAX_ENCRYPTED_OVERHEAD
                        + headerlen + align;
#ifndef OPENSSL_NO_COMP
                if (!(s->options & SSL_OP_NO_COMPRESSION))
                        len += SSL3_RT_MAX_COMPRESSED_OVERHEAD;
#endif
                if (!(s->options & SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS))
                        len += headerlen + align
                                + SSL3_RT_SEND_MAX_ENCRYPTED_OVERHEAD;

                if ((p=freelist_extract(s->ctx, 0, len)) == NULL)
                        goto err;
                s->s3->wbuf.buf = p;
                s->s3->wbuf.len = len;
                }

        return 1;

err:
        SSLerr(SSL_F_SSL3_SETUP_WRITE_BUFFER,ERR_R_MALLOC_FAILURE);
        return 0;
        }


int ssl3_setup_buffers(SSL *s)
        {
        if (!ssl3_setup_read_buffer(s))
                return 0;
        if (!ssl3_setup_write_buffer(s))
                return 0;
        return 1;
        }

int ssl3_release_write_buffer(SSL *s)
        {
        if (s->s3->wbuf.buf != NULL)
                {
                freelist_insert(s->ctx, 0, s->s3->wbuf.len, s->s3->wbuf.buf);
                s->s3->wbuf.buf = NULL;
                }
        return 1;
        }

int ssl3_release_read_buffer(SSL *s)
        {
        if (s->s3->rbuf.buf != NULL)
                {
                freelist_insert(s->ctx, 1, s->s3->rbuf.len, s->s3->rbuf.buf);
                s->s3->rbuf.buf = NULL;
                }
        return 1;
        }