s3_enc.c

mediastreamer2是开源的网络传输媒体流的库

	int num;
	int ret = 0;
	SSL_COMP *comp;

	if (s->s3->tmp.key_block_length != 0)
		return(1);

	if (!ssl_cipher_get_evp(s->session,&c,&hash,&comp))
		{
		SSLerr(SSL_F_SSL3_SETUP_KEY_BLOCK,SSL_R_CIPHER_OR_HASH_UNAVAILABLE);
		return(0);
		}

	s->s3->tmp.new_sym_enc=c;
	s->s3->tmp.new_hash=hash;
#ifdef OPENSSL_NO_COMP
	s->s3->tmp.new_compression=NULL;
#else
	s->s3->tmp.new_compression=comp;
#endif

	num=EVP_CIPHER_key_length(c)+EVP_MD_size(hash)+EVP_CIPHER_iv_length(c);
	num*=2;

	ssl3_cleanup_key_block(s);

	if ((p=OPENSSL_malloc(num)) == NULL)
		goto err;

	s->s3->tmp.key_block_length=num;
	s->s3->tmp.key_block=p;

	ret = ssl3_generate_key_block(s,p,num);

	if (!(s->options & SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS))
		{
		/* enable vulnerability countermeasure for CBC ciphers with
		 * known-IV problem (http://www.openssl.org/~bodo/tls-cbc.txt)
		 */
		s->s3->need_empty_fragments = 1;

		if (s->session->cipher != NULL)
			{
			if ((s->session->cipher->algorithms & SSL_ENC_MASK) == SSL_eNULL)
				s->s3->need_empty_fragments = 0;
			
#ifndef OPENSSL_NO_RC4
			if ((s->session->cipher->algorithms & SSL_ENC_MASK) == SSL_RC4)
				s->s3->need_empty_fragments = 0;
#endif
			}
		}

	return ret;
		
err:
	SSLerr(SSL_F_SSL3_SETUP_KEY_BLOCK,ERR_R_MALLOC_FAILURE);
	return(0);
	}

void ssl3_cleanup_key_block(SSL *s)
	{
	if (s->s3->tmp.key_block != NULL)
		{
		OPENSSL_cleanse(s->s3->tmp.key_block,
			s->s3->tmp.key_block_length);
		OPENSSL_free(s->s3->tmp.key_block);
		s->s3->tmp.key_block=NULL;
		}
	s->s3->tmp.key_block_length=0;
	}

int ssl3_enc(SSL *s, int send)
	{
	SSL3_RECORD *rec;
	EVP_CIPHER_CTX *ds;
	unsigned long l;
	int bs,i;
	const EVP_CIPHER *enc;

	if (send)
		{
		ds=s->enc_write_ctx;
		rec= &(s->s3->wrec);
		if (s->enc_write_ctx == NULL)
			enc=NULL;
		else
			enc=EVP_CIPHER_CTX_cipher(s->enc_write_ctx);
		}
	else
		{
		ds=s->enc_read_ctx;
		rec= &(s->s3->rrec);
		if (s->enc_read_ctx == NULL)
			enc=NULL;
		else
			enc=EVP_CIPHER_CTX_cipher(s->enc_read_ctx);
		}

	if ((s->session == NULL) || (ds == NULL) ||
		(enc == NULL))
		{
		memmove(rec->data,rec->input,rec->length);
		rec->input=rec->data;
		}
	else
		{
		l=rec->length;
		bs=EVP_CIPHER_block_size(ds->cipher);

		/* COMPRESS */

		if ((bs != 1) && send)
			{
			i=bs-((int)l%bs);

			/* we need to add 'i-1' padding bytes */
			l+=i;
			rec->length+=i;
			rec->input[l-1]=(i-1);
			}
		
		if (!send)
			{
			if (l == 0 || l%bs != 0)
				{
				SSLerr(SSL_F_SSL3_ENC,SSL_R_BLOCK_CIPHER_PAD_IS_WRONG);
				ssl3_send_alert(s,SSL3_AL_FATAL,SSL_AD_DECRYPTION_FAILED);
				return 0;
				}
			/* otherwise, rec->length >= bs */
			}
		
		EVP_Cipher(ds,rec->data,rec->input,l);

		if ((bs != 1) && !send)
			{
			i=rec->data[l-1]+1;
			/* SSL 3.0 bounds the number of padding bytes by the block size;
			 * padding bytes (except the last one) are arbitrary */
			if (i > bs)
				{
				/* Incorrect padding. SSLerr() and ssl3_alert are done
				 * by caller: we don't want to reveal whether this is
				 * a decryption error or a MAC verification failure
				 * (see http://www.openssl.org/~bodo/tls-cbc.txt) */
				return -1;
				}
			/* now i <= bs <= rec->length */
			rec->length-=i;
			}
		}
	return(1);
	}

void ssl3_init_finished_mac(SSL *s)
	{
	EVP_DigestInit_ex(&(s->s3->finish_dgst1),s->ctx->md5, NULL);
	EVP_DigestInit_ex(&(s->s3->finish_dgst2),s->ctx->sha1, NULL);
	}

void ssl3_finish_mac(SSL *s, const unsigned char *buf, int len)
	{
	EVP_DigestUpdate(&(s->s3->finish_dgst1),buf,len);
	EVP_DigestUpdate(&(s->s3->finish_dgst2),buf,len);
	}

int ssl3_cert_verify_mac(SSL *s, EVP_MD_CTX *ctx, unsigned char *p)
	{
	return(ssl3_handshake_mac(s,ctx,NULL,0,p));
	}

int ssl3_final_finish_mac(SSL *s, EVP_MD_CTX *ctx1, EVP_MD_CTX *ctx2,
	     const char *sender, int len, unsigned char *p)
	{
	int ret;

	ret=ssl3_handshake_mac(s,ctx1,sender,len,p);
	p+=ret;
	ret+=ssl3_handshake_mac(s,ctx2,sender,len,p);
	return(ret);
	}

static int ssl3_handshake_mac(SSL *s, EVP_MD_CTX *in_ctx,
	     const char *sender, int len, unsigned char *p)
	{
	unsigned int ret;
	int npad,n;
	unsigned int i;
	unsigned char md_buf[EVP_MAX_MD_SIZE];
	EVP_MD_CTX ctx;

	EVP_MD_CTX_init(&ctx);
	EVP_MD_CTX_copy_ex(&ctx,in_ctx);

	n=EVP_MD_CTX_size(&ctx);
	npad=(48/n)*n;

	if (sender != NULL)
		EVP_DigestUpdate(&ctx,sender,len);
	EVP_DigestUpdate(&ctx,s->session->master_key,
		s->session->master_key_length);
	EVP_DigestUpdate(&ctx,ssl3_pad_1,npad);
	EVP_DigestFinal_ex(&ctx,md_buf,&i);

	EVP_DigestInit_ex(&ctx,EVP_MD_CTX_md(&ctx), NULL);
	EVP_DigestUpdate(&ctx,s->session->master_key,
		s->session->master_key_length);
	EVP_DigestUpdate(&ctx,ssl3_pad_2,npad);
	EVP_DigestUpdate(&ctx,md_buf,i);
	EVP_DigestFinal_ex(&ctx,p,&ret);

	EVP_MD_CTX_cleanup(&ctx);

	return((int)ret);
	}

int ssl3_mac(SSL *ssl, unsigned char *md, int send)
	{
	SSL3_RECORD *rec;
	unsigned char *mac_sec,*seq;
	EVP_MD_CTX md_ctx;
	const EVP_MD *hash;
	unsigned char *p,rec_char;
	unsigned int md_size;
	int npad;

	if (send)
		{
		rec= &(ssl->s3->wrec);
		mac_sec= &(ssl->s3->write_mac_secret[0]);
		seq= &(ssl->s3->write_sequence[0]);
		hash=ssl->write_hash;
		}
	else
		{
		rec= &(ssl->s3->rrec);
		mac_sec= &(ssl->s3->read_mac_secret[0]);
		seq= &(ssl->s3->read_sequence[0]);
		hash=ssl->read_hash;
		}

	md_size=EVP_MD_size(hash);
	npad=(48/md_size)*md_size;

	/* Chop the digest off the end :-) */
	EVP_MD_CTX_init(&md_ctx);

	EVP_DigestInit_ex(  &md_ctx,hash, NULL);
	EVP_DigestUpdate(&md_ctx,mac_sec,md_size);
	EVP_DigestUpdate(&md_ctx,ssl3_pad_1,npad);
	EVP_DigestUpdate(&md_ctx,seq,8);
	rec_char=rec->type;
	EVP_DigestUpdate(&md_ctx,&rec_char,1);
	p=md;
	s2n(rec->length,p);
	EVP_DigestUpdate(&md_ctx,md,2);
	EVP_DigestUpdate(&md_ctx,rec->input,rec->length);
	EVP_DigestFinal_ex( &md_ctx,md,NULL);

	EVP_DigestInit_ex(  &md_ctx,hash, NULL);
	EVP_DigestUpdate(&md_ctx,mac_sec,md_size);
	EVP_DigestUpdate(&md_ctx,ssl3_pad_2,npad);
	EVP_DigestUpdate(&md_ctx,md,md_size);
	EVP_DigestFinal_ex( &md_ctx,md,&md_size);

	EVP_MD_CTX_cleanup(&md_ctx);

	ssl3_record_sequence_update(seq);
	return(md_size);
	}

void ssl3_record_sequence_update(unsigned char *seq)
	{
	int i;

	for (i=7; i>=0; i--)
		{
		++seq[i];
		if (seq[i] != 0) break; 
		}
	}

int ssl3_generate_master_secret(SSL *s, unsigned char *out, unsigned char *p,
	     int len)
	{
	static const unsigned char *salt[3]={
#ifndef CHARSET_EBCDIC
		(const unsigned char *)"A",
		(const unsigned char *)"BB",
		(const unsigned char *)"CCC",
#else
		(const unsigned char *)"\x41",
		(const unsigned char *)"\x42\x42",
		(const unsigned char *)"\x43\x43\x43",
#endif
		};
	unsigned char buf[EVP_MAX_MD_SIZE];
	EVP_MD_CTX ctx;
	int i,ret=0;
	unsigned int n;

	EVP_MD_CTX_init(&ctx);
	for (i=0; i<3; i++)
		{
		EVP_DigestInit_ex(&ctx,s->ctx->sha1, NULL);
		EVP_DigestUpdate(&ctx,salt[i],strlen((const char *)salt[i]));
		EVP_DigestUpdate(&ctx,p,len);
		EVP_DigestUpdate(&ctx,&(s->s3->client_random[0]),
			SSL3_RANDOM_SIZE);
		EVP_DigestUpdate(&ctx,&(s->s3->server_random[0]),
			SSL3_RANDOM_SIZE);
		EVP_DigestFinal_ex(&ctx,buf,&n);

		EVP_DigestInit_ex(&ctx,s->ctx->md5, NULL);
		EVP_DigestUpdate(&ctx,p,len);
		EVP_DigestUpdate(&ctx,buf,n);
		EVP_DigestFinal_ex(&ctx,out,&n);
		out+=n;
		ret+=n;
		}
	EVP_MD_CTX_cleanup(&ctx);
	return(ret);
	}

int ssl3_alert_code(int code)
	{
	switch (code)
		{
	case SSL_AD_CLOSE_NOTIFY:	return(SSL3_AD_CLOSE_NOTIFY);
	case SSL_AD_UNEXPECTED_MESSAGE:	return(SSL3_AD_UNEXPECTED_MESSAGE);
	case SSL_AD_BAD_RECORD_MAC:	return(SSL3_AD_BAD_RECORD_MAC);
	case SSL_AD_DECRYPTION_FAILED:	return(SSL3_AD_BAD_RECORD_MAC);
	case SSL_AD_RECORD_OVERFLOW:	return(SSL3_AD_BAD_RECORD_MAC);
	case SSL_AD_DECOMPRESSION_FAILURE:return(SSL3_AD_DECOMPRESSION_FAILURE);
	case SSL_AD_HANDSHAKE_FAILURE:	return(SSL3_AD_HANDSHAKE_FAILURE);
	case SSL_AD_NO_CERTIFICATE:	return(SSL3_AD_NO_CERTIFICATE);
	case SSL_AD_BAD_CERTIFICATE:	return(SSL3_AD_BAD_CERTIFICATE);
	case SSL_AD_UNSUPPORTED_CERTIFICATE:return(SSL3_AD_UNSUPPORTED_CERTIFICATE);
	case SSL_AD_CERTIFICATE_REVOKED:return(SSL3_AD_CERTIFICATE_REVOKED);
	case SSL_AD_CERTIFICATE_EXPIRED:return(SSL3_AD_CERTIFICATE_EXPIRED);
	case SSL_AD_CERTIFICATE_UNKNOWN:return(SSL3_AD_CERTIFICATE_UNKNOWN);
	case SSL_AD_ILLEGAL_PARAMETER:	return(SSL3_AD_ILLEGAL_PARAMETER);
	case SSL_AD_UNKNOWN_CA:		return(SSL3_AD_BAD_CERTIFICATE);
	case SSL_AD_ACCESS_DENIED:	return(SSL3_AD_HANDSHAKE_FAILURE);
	case SSL_AD_DECODE_ERROR:	return(SSL3_AD_HANDSHAKE_FAILURE);
	case SSL_AD_DECRYPT_ERROR:	return(SSL3_AD_HANDSHAKE_FAILURE);
	case SSL_AD_EXPORT_RESTRICTION:	return(SSL3_AD_HANDSHAKE_FAILURE);
	case SSL_AD_PROTOCOL_VERSION:	return(SSL3_AD_HANDSHAKE_FAILURE);
	case SSL_AD_INSUFFICIENT_SECURITY:return(SSL3_AD_HANDSHAKE_FAILURE);
	case SSL_AD_INTERNAL_ERROR:	return(SSL3_AD_HANDSHAKE_FAILURE);
	case SSL_AD_USER_CANCELLED:	return(SSL3_AD_HANDSHAKE_FAILURE);
	case SSL_AD_NO_RENEGOTIATION:	return(-1); /* Don't send it :-) */
	default:			return(-1);
		}
	}