s3_pkt.c

mediastreamer2是开源的网络传输媒体流的库

/* ssl/s3_pkt.c */
/* Copyright (C) 1995-1998 Eric Young ([e-mail])
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young ([e-mail]).
 * 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 ([e-mail]).
 * 
 * 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 ([e-mail])"
 *    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 ([e-mail])"
 * 
 * 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
 *    [e-mail].
 *
 * 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
 * ([e-mail]).  This product includes software written by Tim
 * Hudson ([e-mail]).
 *
 */

#include <stdio.h>
#include <errno.h>
#define USE_SOCKETS
#include "ssl_locl.h"
#include <openssl/evp.h>
#include <openssl/buffer.h>

static int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
			 unsigned int len, int create_empty_fragment);
static int ssl3_get_record(SSL *s);

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

	if (!extend)
		{
		/* start with empty packet ... */
		if (s->s3->rbuf.left == 0)
			s->s3->rbuf.offset = 0;
		s->packet = s->s3->rbuf.buf + s->s3->rbuf.offset;
		s->packet_length = 0;
		/* ... now we can act as if 'extend' was set */
		}

	/* extend reads should not span multiple packets for DTLS */
	if ( SSL_version(s) == DTLS1_VERSION &&
		extend)
		{
		if ( s->s3->rbuf.left > 0 && n > s->s3->rbuf.left)
			n = s->s3->rbuf.left;
		}

	/* if there is enough in the buffer from a previous read, take some */
	if (s->s3->rbuf.left >= (int)n)
		{
		s->packet_length+=n;
		s->s3->rbuf.left-=n;
		s->s3->rbuf.offset+=n;
		return(n);
		}

	/* else we need to read more data */
	if (!s->read_ahead)
		max=n;

	{
		/* avoid buffer overflow */
		int max_max = s->s3->rbuf.len - s->packet_length;
		if (max > max_max)
			max = max_max;
	}
	if (n > max) /* does not happen */
		{
		SSLerr(SSL_F_SSL3_READ_N,ERR_R_INTERNAL_ERROR);
		return -1;
		}

	off = s->packet_length;
	newb = s->s3->rbuf.left;
	/* Move any available bytes to front of buffer:
	 * 'off' bytes already pointed to by 'packet',
	 * 'newb' extra ones at the end */
	if (s->packet != s->s3->rbuf.buf)
		{
		/*  off > 0 */
		memmove(s->s3->rbuf.buf, s->packet, off+newb);
		s->packet = s->s3->rbuf.buf;
		}

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

		clear_sys_error();
		if (s->rbio != NULL)
			{
			s->rwstate=SSL_READING;
			i=BIO_read(s->rbio,	&(s->s3->rbuf.buf[off+newb]), max-newb);
			}
		else
			{
			SSLerr(SSL_F_SSL3_READ_N,SSL_R_READ_BIO_NOT_SET);
			i = -1;
			}

		if (i <= 0)
			{
			s->s3->rbuf.left = newb;
			return(i);
			}
		newb+=i;
		}

	/* done reading, now the book-keeping */
	s->s3->rbuf.offset = off + n;
	s->s3->rbuf.left = newb - n;
	s->packet_length += n;
	s->rwstate=SSL_NOTHING;
	return(n);
	}

/* Call this to get a new input record.
 * It will return <= 0 if more data is needed, normally due to an error
 * or non-blocking IO.
 * When it finishes, one packet has been decoded and can be found in
 * ssl->s3->rrec.type    - is the type of record
 * ssl->s3->rrec.data, 	 - data
 * ssl->s3->rrec.length, - number of bytes
 */
/* used only by ssl3_read_bytes */
static int ssl3_get_record(SSL *s)
	{
	int ssl_major,ssl_minor,al;
	int enc_err,n,i,ret= -1;
	SSL3_RECORD *rr;
	SSL_SESSION *sess;
	unsigned char *p;
	unsigned char md[EVP_MAX_MD_SIZE];
	short version;
	unsigned int mac_size;
	int clear=0;
	size_t extra;
	int decryption_failed_or_bad_record_mac = 0;
	unsigned char *mac = NULL;

	rr= &(s->s3->rrec);
	sess=s->session;

	if (s->options & SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER)
		extra=SSL3_RT_MAX_EXTRA;
	else
		extra=0;
	if (extra != s->s3->rbuf.len - SSL3_RT_MAX_PACKET_SIZE)
		{
		/* actually likely an application error: SLS_OP_MICROSOFT_BIG_SSLV3_BUFFER
		 * set after ssl3_setup_buffers() was done */
		SSLerr(SSL_F_SSL3_GET_RECORD, ERR_R_INTERNAL_ERROR);
		return -1;
		}

again:
	/* check if we have the header */
	if (	(s->rstate != SSL_ST_READ_BODY) ||
		(s->packet_length < SSL3_RT_HEADER_LENGTH)) 
		{
		n=ssl3_read_n(s, SSL3_RT_HEADER_LENGTH, s->s3->rbuf.len, 0);
		if (n <= 0) return(n); /* error or non-blocking */
		s->rstate=SSL_ST_READ_BODY;

		p=s->packet;

		/* Pull apart the header into the SSL3_RECORD */
		rr->type= *(p++);
		ssl_major= *(p++);
		ssl_minor= *(p++);
		version=(ssl_major<<8)|ssl_minor;
		n2s(p,rr->length);

		/* Lets check version */
		if (s->first_packet)
			{
			s->first_packet=0;
			}
		else
			{
			if (version != s->version)
				{
				SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_WRONG_VERSION_NUMBER);
				/* Send back error using their
				 * version number :-) */
				s->version=version;
				al=SSL_AD_PROTOCOL_VERSION;
				goto f_err;
				}
			}

		if ((version>>8) != SSL3_VERSION_MAJOR)
			{
			SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_WRONG_VERSION_NUMBER);
			goto err;
			}

		if (rr->length > SSL3_RT_MAX_ENCRYPTED_LENGTH+extra)
			{
			al=SSL_AD_RECORD_OVERFLOW;
			SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_PACKET_LENGTH_TOO_LONG);
			goto f_err;
			}

		/* now s->rstate == SSL_ST_READ_BODY */
		}

	/* s->rstate == SSL_ST_READ_BODY, get and decode the data */

	if (rr->length > s->packet_length-SSL3_RT_HEADER_LENGTH)
		{
		/* now s->packet_length == SSL3_RT_HEADER_LENGTH */
		i=rr->length;
		n=ssl3_read_n(s,i,i,1);
		if (n <= 0) return(n); /* error or non-blocking io */
		/* now n == rr->length,
		 * and s->packet_length == SSL3_RT_HEADER_LENGTH + rr->length */
		}

	s->rstate=SSL_ST_READ_HEADER; /* set state for later operations */

	/* At this point, s->packet_length == SSL3_RT_HEADER_LNGTH + rr->length,
	 * and we have that many bytes in s->packet
	 */
	rr->input= &(s->packet[SSL3_RT_HEADER_LENGTH]);

	/* ok, we can now read from 's->packet' data into 'rr'
	 * rr->input points at rr->length bytes, which
	 * need to be copied into rr->data by either
	 * the decryption or by the decompression
	 * When the data is 'copied' into the rr->data buffer,
	 * rr->input will be pointed at the new buffer */ 

	/* We now have - encrypted [ MAC [ compressed [ plain ] ] ]
	 * rr->length bytes of encrypted compressed stuff. */

	/* check is not needed I believe */
	if (rr->length > SSL3_RT_MAX_ENCRYPTED_LENGTH+extra)
		{
		al=SSL_AD_RECORD_OVERFLOW;
		SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_ENCRYPTED_LENGTH_TOO_LONG);
		goto f_err;
		}

	/* decrypt in place in 'rr->input' */
	rr->data=rr->input;

	enc_err = s->method->ssl3_enc->enc(s,0);
	if (enc_err <= 0)
		{
		if (enc_err == 0)
			/* SSLerr() and ssl3_send_alert() have been called */
			goto err;

		/* Otherwise enc_err == -1, which indicates bad padding
		 * (rec->length has not been changed in this case).
		 * To minimize information leaked via timing, we will perform
		 * the MAC computation anyway. */
		decryption_failed_or_bad_record_mac = 1;
		}

#ifdef TLS_DEBUG
printf("dec %d\n",rr->length);
{ unsigned int z; for (z=0; z<rr->length; z++) printf("%02X%c",rr->data[z],((z+1)%16)?' ':'\n'); }
printf("\n");
#endif

	/* r->length is now the compressed data plus mac */
	if (	(sess == NULL) ||
		(s->enc_read_ctx == NULL) ||
		(s->read_hash == NULL))
		clear=1;

	if (!clear)
		{
		mac_size=EVP_MD_size(s->read_hash);

		if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+extra+mac_size)
			{
#if 0 /* OK only for stream ciphers (then rr->length is visible from ciphertext anyway) */
			al=SSL_AD_RECORD_OVERFLOW;
			SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_PRE_MAC_LENGTH_TOO_LONG);
			goto f_err;
#else
			decryption_failed_or_bad_record_mac = 1;
#endif			
			}
		/* check the MAC for rr->input (it's in mac_size bytes at the tail) */
		if (rr->length >= mac_size)
			{
			rr->length -= mac_size;
			mac = &rr->data[rr->length];
			}
		else
			{
			/* record (minus padding) is too short to contain a MAC */
#if 0 /* OK only for stream ciphers */
			al=SSL_AD_DECODE_ERROR;
			SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_LENGTH_TOO_SHORT);
			goto f_err;
#else
			decryption_failed_or_bad_record_mac = 1;
			rr->length = 0;
#endif
			}
		i=s->method->ssl3_enc->mac(s,md,0);
		if (mac == NULL || memcmp(md, mac, mac_size) != 0)
			{
			decryption_failed_or_bad_record_mac = 1;
			}
		}

	if (decryption_failed_or_bad_record_mac)
		{
		/* A separate 'decryption_failed' alert was introduced with TLS 1.0,
		 * SSL 3.0 only has 'bad_record_mac'.  But unless a decryption
		 * failure is directly visible from the ciphertext anyway,
		 * we should not reveal which kind of error occured -- this
		 * might become visible to an attacker (e.g. via a logfile) */
		al=SSL_AD_BAD_RECORD_MAC;
		SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC);
		goto f_err;
		}

	/* r->length is now just compressed */
	if (s->expand != NULL)
		{
		if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+extra)
			{
			al=SSL_AD_RECORD_OVERFLOW;
			SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_COMPRESSED_LENGTH_TOO_LONG);
			goto f_err;
			}
		if (!ssl3_do_uncompress(s))