/* 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;

    int i;

    unsigned long l;

    if (s->state == a) {

        p = ssl_handshake_start(s);

        i = s->method->ssl3_enc->final_finish_mac(s,

                                                  sender, slen,

                                                  s->s3->tmp.finish_md);

        if (i <= 0)

            return 0;

        s->s3->tmp.finish_md_len = i;

        memcpy(p, s->s3->tmp.finish_md, 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

        ssl_set_handshake_header(s, SSL3_MT_FINISHED, l);

        s->state = b;

    }

    /* SSL3_ST_SEND_xxxxxx_HELLO_B */

    return ssl_do_write(s);

}

#ifndef OPENSSL_NO_NEXTPROTONEG

/*

 * ssl3_take_mac calculates the Finished MAC for the handshakes messages seen

 * to far.

 */

static void ssl3_take_mac(SSL *s)

{

    const char *sender;

    int slen;

    /*

     * If no new cipher setup return immediately: other functions will set

     * the appropriate error.

     */

    if (s->s3->tmp.new_cipher == NULL)

        return;

    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;

    }

    s->s3->tmp.peer_finish_md_len = s->method->ssl3_enc->final_finish_mac(s,

                                                                          sender,

                                                                          slen,

                                                                          s->s3->tmp.peer_finish_md);

}

#endif

int ssl3_get_finished(SSL *s, int a, int b)

{

    int al, i, ok;

    long n;

    unsigned char *p;

#ifdef OPENSSL_NO_NEXTPROTONEG

    /*

     * the mac has already been generated when we received the change cipher

     * spec message and is in s->s3->tmp.peer_finish_md

     */

#endif

    /* 64 argument should actually be 36+4 :-) */

    n = s->method->ssl_get_message(s, a, b, SSL3_MT_FINISHED, 64, &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 (CRYPTO_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));

}

unsigned long ssl3_output_cert_chain(SSL *s, CERT_PKEY *cpk)

{

    unsigned char *p;

    unsigned long l = 3 + SSL_HM_HEADER_LENGTH(s);

    if (!ssl_add_cert_chain(s, cpk, &l))

        return 0;

    l -= 3 + SSL_HM_HEADER_LENGTH(s);

    p = ssl_handshake_start(s);

    l2n3(l, p);

    l += 3;

    ssl_set_handshake_header(s, SSL3_MT_CERTIFICATE, l);

    return l + SSL_HM_HEADER_LENGTH(s);

}

/*

 * 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->state = stn;

        s->init_msg = s->init_buf->data + SSL3_HM_HEADER_LENGTH;

        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 < SSL3_HM_HEADER_LENGTH */

        int skip_message;

        do {

            while (s->init_num < SSL3_HM_HEADER_LENGTH) {

                i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE,

                                              &p[s->init_num],

                                              SSL3_HM_HEADER_LENGTH -

                                              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, SSL3_HM_HEADER_LENGTH, s,

                                            s->msg_callback_arg);

                    }

        }

        while (skip_message);

        /* s->init_num == SSL3_HM_HEADER_LENGTH */

        if ((mt >= 0) && (*p != mt)) {

            al = SSL_AD_UNEXPECTED_MESSAGE;

            SSLerr(SSL_F_SSL3_GET_MESSAGE, SSL_R_UNEXPECTED_MESSAGE);

            goto f_err;

        }

        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;

        }

        /*

         * Make buffer slightly larger than message length as a precaution

         * against small OOB reads e.g. CVE-2016-6306

         */

        if (l

            && !BUF_MEM_grow_clean(s->init_buf,

                                   (int)l + SSL3_HM_HEADER_LENGTH + 16)) {

            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 + SSL3_HM_HEADER_LENGTH;

        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;

    }

#ifndef OPENSSL_NO_NEXTPROTONEG

    /*

     * If receiving Finished, record MAC of prior handshake messages for

     * Finished verification.

     */

    if (*s->init_buf->data == SSL3_MT_FINISHED)

        ssl3_take_mac(s);

#endif

    /* Feed this message into MAC computation. */

    ssl3_finish_mac(s, (unsigned char *)s->init_buf->data,

                    s->init_num + SSL3_HM_HEADER_LENGTH);

    if (s->msg_callback)

        s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, s->init_buf->data,

                        (size_t)s->init_num + SSL3_HM_HEADER_LENGTH, 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;

    } else if (x && (i == EVP_PKEY_DH || i == EVP_PKEY_DHX)) {

        /*

         * For DH two cases: DH certificate signed with RSA and DH

         * certificate signed with DSA.

         */

        i = X509_certificate_type(x, pk);

        if (i & EVP_PKS_RSA)

            ret = SSL_PKEY_DH_RSA;

        else if (i & EVP_PKS_DSA)

            ret = SSL_PKEY_DH_DSA;

    }

 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:

    case X509_V_ERR_HOSTNAME_MISMATCH:

    case X509_V_ERR_EMAIL_MISMATCH:

    case X509_V_ERR_IP_ADDRESS_MISMATCH:

        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_UNSPECIFIED:

    case X509_V_ERR_OUT_OF_MEM:

    case X509_V_ERR_INVALID_CALL:

    case X509_V_ERR_STORE_LOOKUP:

        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_IS_DTLS(s))

        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_IS_DTLS(s))

        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;

}