Commit message: Fixed NULL pointer dereference. See PR#3321
CVE: None
Vulnerability description: None

Project: openssl

int ssl3_write_bytes(SSL *s, int type, const void *buf_, int len)
	{
	const unsigned char *buf=buf_;
	unsigned int tot,n,nw;
	int i;

	s->rwstate=SSL_NOTHING;
	tot=s->s3->wnum;
	s->s3->wnum=0;

	if (SSL_in_init(s) && !s->in_handshake)
		{
		i=s->handshake_func(s);
		if (i < 0) return(i);
		if (i == 0)
			{
			SSLerr(SSL_F_SSL3_WRITE_BYTES,SSL_R_SSL_HANDSHAKE_FAILURE);
			return -1;
			}
		}

	/* ensure that if we end up with a smaller value of data to write 
	 * out than the the original len from a write which didn't complete 
	 * for non-blocking I/O and also somehow ended up avoiding 
	 * the check for this in ssl3_write_pending/SSL_R_BAD_WRITE_RETRY as
	 * it must never be possible to end up with (len-tot) as a large
	 * number that will then promptly send beyond the end of the users
	 * buffer ... so we trap and report the error in a way the user
	 * will notice
	 */
	if ( len < tot)
		{
		SSLerr(SSL_F_SSL3_WRITE_BYTES,SSL_R_BAD_LENGTH);
		return(-1);
		}


	n=(len-tot);
	for (;;)
		{
		if (n > s->max_send_fragment)
			nw=s->max_send_fragment;
		else
			nw=n;

		i=do_ssl3_write(s, type, &(buf[tot]), nw, 0);
		if (i <= 0)
			{
			s->s3->wnum=tot;
			return i;
			}

		if ((i == (int)n) ||
			(type == SSL3_RT_APPLICATION_DATA &&
			 (s->mode & SSL_MODE_ENABLE_PARTIAL_WRITE)))
			{
			/* next chunk of data should get another prepended empty fragment
			 * in ciphersuites with known-IV weakness: */
			s->s3->empty_fragment_done = 0;
			
			return tot+i;
			}

		n-=i;
		tot+=i;
		}
	}

Project: openssl

static int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
			 unsigned int len, int create_empty_fragment)
	{
	unsigned char *p,*plen;
	int i,mac_size,clear=0;
	int prefix_len=0;
	int eivlen;
	long align=0;
	SSL3_RECORD *wr;
	SSL3_BUFFER *wb=&(s->s3->wbuf);
	SSL_SESSION *sess;


	/* first check if there is a SSL3_BUFFER still being written
	 * out.  This will happen with non blocking IO */
	if (wb->left != 0)
		return(ssl3_write_pending(s,type,buf,len));

	/* If we have an alert to send, lets send it */
	if (s->s3->alert_dispatch)
		{
		i=s->method->ssl_dispatch_alert(s);
		if (i <= 0)
			return(i);
		/* if it went, fall through and send more stuff */
		}

 	if (wb->buf == NULL)
		if (!ssl3_setup_write_buffer(s))
			return -1;

	if (len == 0 && !create_empty_fragment)
		return 0;

	wr= &(s->s3->wrec);
	sess=s->session;

	if (	(sess == NULL) ||
		(s->enc_write_ctx == NULL) ||
		(EVP_MD_CTX_md(s->write_hash) == NULL))
		{
#if 1
		clear=s->enc_write_ctx?0:1;	/* must be AEAD cipher */
#else
		clear=1;
#endif
		mac_size=0;
		}
	else
		{
		mac_size=EVP_MD_CTX_size(s->write_hash);
		if (mac_size < 0)
			goto err;
		}

	/* 'create_empty_fragment' is true only when this function calls itself */
	if (!clear && !create_empty_fragment && !s->s3->empty_fragment_done)
		{
		/* countermeasure against known-IV weakness in CBC ciphersuites
		 * (see http://www.openssl.org/~bodo/tls-cbc.txt) */

		if (s->s3->need_empty_fragments && type == SSL3_RT_APPLICATION_DATA)
			{
			/* recursive function call with 'create_empty_fragment' set;
			 * this prepares and buffers the data for an empty fragment
			 * (these 'prefix_len' bytes are sent out later
			 * together with the actual payload) */
			prefix_len = do_ssl3_write(s, type, buf, 0, 1);
			if (prefix_len <= 0)
				goto err;

			if (prefix_len >
		(SSL3_RT_HEADER_LENGTH + SSL3_RT_SEND_MAX_ENCRYPTED_OVERHEAD))
				{
				/* insufficient space */
				SSLerr(SSL_F_DO_SSL3_WRITE, ERR_R_INTERNAL_ERROR);
				goto err;
				}
			}
		
		s->s3->empty_fragment_done = 1;
		}

	if (create_empty_fragment)
		{
#if defined(SSL3_ALIGN_PAYLOAD) && SSL3_ALIGN_PAYLOAD!=0
		/* extra fragment would be couple of cipher blocks,
		 * which would be multiple of SSL3_ALIGN_PAYLOAD, so
		 * if we want to align the real payload, then we can
		 * just pretent we simply have two headers. */
		align = (long)wb->buf + 2*SSL3_RT_HEADER_LENGTH;
		align = (-align)&(SSL3_ALIGN_PAYLOAD-1);
#endif
		p = wb->buf + align;
		wb->offset  = align;
		}
	else if (prefix_len)
		{
		p = wb->buf + wb->offset + prefix_len;
		}
	else
		{
#if defined(SSL3_ALIGN_PAYLOAD) && SSL3_ALIGN_PAYLOAD!=0
		align = (long)wb->buf + SSL3_RT_HEADER_LENGTH;
		align = (-align)&(SSL3_ALIGN_PAYLOAD-1);
#endif
		p = wb->buf + align;
		wb->offset  = align;
		}

	/* write the header */

	*(p++)=type&0xff;
	wr->type=type;

	*(p++)=(s->version>>8);
	/* Some servers hang if iniatial client hello is larger than 256
	 * bytes and record version number > TLS 1.0
	 */
	if (s->state == SSL3_ST_CW_CLNT_HELLO_B
				&& !s->renegotiate
				&& TLS1_get_version(s) > TLS1_VERSION)
		*(p++) = 0x1;
	else
		*(p++)=s->version&0xff;

	/* field where we are to write out packet length */
	plen=p; 
	p+=2;
	/* Explicit IV length, block ciphers and TLS version 1.1 or later */
	if (s->enc_write_ctx && s->version >= TLS1_1_VERSION)
		{
		int mode = EVP_CIPHER_CTX_mode(s->enc_write_ctx);
		if (mode == EVP_CIPH_CBC_MODE)
			{
			eivlen = EVP_CIPHER_CTX_iv_length(s->enc_write_ctx);
			if (eivlen <= 1)
				eivlen = 0;
			}
		/* Need explicit part of IV for GCM mode */
		else if (mode == EVP_CIPH_GCM_MODE)
			eivlen = EVP_GCM_TLS_EXPLICIT_IV_LEN;
		else
			eivlen = 0;
		}
	else 
		eivlen = 0;

	/* lets setup the record stuff. */
	wr->data=p + eivlen;
	wr->length=(int)len;
	wr->input=(unsigned char *)buf;

	/* we now 'read' from wr->input, wr->length bytes into
	 * wr->data */

	/* first we compress */
	if (s->compress != NULL)
		{
		if (!ssl3_do_compress(s))
			{
			SSLerr(SSL_F_DO_SSL3_WRITE,SSL_R_COMPRESSION_FAILURE);
			goto err;
			}
		}
	else
		{
		memcpy(wr->data,wr->input,wr->length);
		wr->input=wr->data;
		}

	/* we should still have the output to wr->data and the input
	 * from wr->input.  Length should be wr->length.
	 * wr->data still points in the wb->buf */

	if (mac_size != 0)
		{
		if (s->method->ssl3_enc->mac(s,&(p[wr->length + eivlen]),1) < 0)
			goto err;
		wr->length+=mac_size;
		}

	wr->input=p;
	wr->data=p;

	if (eivlen)
		{
	/*	if (RAND_pseudo_bytes(p, eivlen) <= 0)
			goto err; */
		wr->length += eivlen;
		}

	/* ssl3_enc can only have an error on read */
	s->method->ssl3_enc->enc(s,1);

	/* record length after mac and block padding */
	s2n(wr->length,plen);

	/* we should now have
	 * wr->data pointing to the encrypted data, which is
	 * wr->length long */
	wr->type=type; /* not needed but helps for debugging */
	wr->length+=SSL3_RT_HEADER_LENGTH;

	if (create_empty_fragment)
		{
		/* we are in a recursive call;
		 * just return the length, don't write out anything here
		 */
		return wr->length;
		}

	/* now let's set up wb */
	wb->left = prefix_len + wr->length;

	/* memorize arguments so that ssl3_write_pending can detect bad write retries later */
	s->s3->wpend_tot=len;
	s->s3->wpend_buf=buf;
	s->s3->wpend_type=type;
	s->s3->wpend_ret=len;

	/* we now just need to write the buffer */
	return ssl3_write_pending(s,type,buf,len);
err:
	return -1;
	}

Project: openssl

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 mac_size, orig_len;
	size_t extra;

	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->init_extra)
		{
		/* 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);
#if 0
fprintf(stderr, "Record type=%d, Length=%d\n", rr->type, rr->length);
#endif

		/* Lets check version */
		if (!s->first_packet)
			{
			if (version != s->version)
				{
				SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_WRONG_VERSION_NUMBER);
                                if ((s->version & 0xFF00) == (version & 0xFF00) && !s->enc_write_ctx && !s->write_hash)
                                	/* Send back error using their minor version number :-) */
					s->version = (unsigned short)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 > s->s3->rbuf.len - SSL3_RT_HEADER_LENGTH)
			{
			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);
	/* enc_err is:
	 *    0: (in non-constant time) if the record is publically invalid.
	 *    1: if the padding is valid
	 *    -1: if the padding is invalid */
	if (enc_err == 0)
		{
		al=SSL_AD_DECRYPTION_FAILED;
		SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_BLOCK_CIPHER_PAD_IS_WRONG);
		goto f_err;
		}

#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) &&
	    (EVP_MD_CTX_md(s->read_hash) != NULL))
		{
		/* s->read_hash != NULL => mac_size != -1 */
		unsigned char *mac = NULL;
		unsigned char mac_tmp[EVP_MAX_MD_SIZE];
		mac_size=EVP_MD_CTX_size(s->read_hash);
		OPENSSL_assert(mac_size <= EVP_MAX_MD_SIZE);

		/* kludge: *_cbc_remove_padding passes padding length in rr->type */
		orig_len = rr->length+((unsigned int)rr->type>>8);

		/* orig_len is the length of the record before any padding was
		 * removed. This is public information, as is the MAC in use,
		 * therefore we can safely process the record in a different
		 * amount of time if it's too short to possibly contain a MAC.
		 */
		if (orig_len < mac_size ||
		    /* CBC records must have a padding length byte too. */
		    (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE &&
		     orig_len < mac_size+1))
			{
			al=SSL_AD_DECODE_ERROR;
			SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_LENGTH_TOO_SHORT);
			goto f_err;
			}

		if (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE)
			{
			/* We update the length so that the TLS header bytes
			 * can be constructed correctly but we need to extract
			 * the MAC in constant time from within the record,
			 * without leaking the contents of the padding bytes.
			 * */
			mac = mac_tmp;
			ssl3_cbc_copy_mac(mac_tmp, rr, mac_size, orig_len);
			rr->length -= mac_size;
			}
		else
			{
			/* In this case there's no padding, so |orig_len|
			 * equals |rec->length| and we checked that there's
			 * enough bytes for |mac_size| above. */
			rr->length -= mac_size;
			mac = &rr->data[rr->length];
			}

		i=s->method->ssl3_enc->mac(s,md,0 /* not send */);
		if (i < 0 || mac == NULL || CRYPTO_memcmp(md, mac, (size_t)mac_size) != 0)
			enc_err = -1;
		if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+extra+mac_size)
			enc_err = -1;
		}

	if (enc_err < 0)
		{
		/* 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))
			{
			al=SSL_AD_DECOMPRESSION_FAILURE;
			SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_BAD_DECOMPRESSION);
			goto f_err;
			}
		}

	if (rr->length > SSL3_RT_MAX_PLAIN_LENGTH+extra)
		{
		al=SSL_AD_RECORD_OVERFLOW;
		SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_DATA_LENGTH_TOO_LONG);
		goto f_err;
		}

	rr->off=0;
	/* So at this point the following is true
	 * ssl->s3->rrec.type 	is the type of record
	 * ssl->s3->rrec.length	== number of bytes in record
	 * ssl->s3->rrec.off	== offset to first valid byte
	 * ssl->s3->rrec.data	== where to take bytes from, increment
	 *			   after use :-).
	 */

	/* we have pulled in a full packet so zero things */
	s->packet_length=0;

	/* just read a 0 length packet */
	if (rr->length == 0) goto again;

#if 0
fprintf(stderr, "Ultimate Record type=%d, Length=%d\n", rr->type, rr->length);
#endif

	return(1);

f_err:
	ssl3_send_alert(s,SSL3_AL_FATAL,al);
err:
	return(ret);
	}