X-Git-Url: https://git.openssl.org/?p=openssl.git;a=blobdiff_plain;f=ssl%2Fs3_pkt.c;h=fc913c2d9e69b96ba02fef7b3015c9f547afc8c3;hp=fd344c4ceb1e45786f3fee881689989b1e75ae55;hb=a01d9ac5582657cd2579153b8c5987b4201f1688;hpb=1b8a8088a5d55d5474fd7f89bc991326cc0430d7

diff --git a/ssl/s3_pkt.c b/ssl/s3_pkt.c
index fd344c4ceb..fc913c2d9e 100644
--- a/ssl/s3_pkt.c
+++ b/ssl/s3_pkt.c
@@ -56,7 +56,7 @@
  * [including the GNU Public Licence.]
  */
 /* ====================================================================
- * Copyright (c) 1998-1999 The OpenSSL Project.  All rights reserved.
+ * 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
@@ -112,21 +112,15 @@
 #include <stdio.h>
 #include <errno.h>
 #define USE_SOCKETS
+#include "ssl_locl.h"
 #include <openssl/evp.h>
 #include <openssl/buffer.h>
-#include "ssl_locl.h"
 
 static int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
-			 unsigned int len);
-static int ssl3_write_pending(SSL *s, int type, const unsigned char *buf,
-			      unsigned int len);
+			 unsigned int len, int create_empty_fragment);
 static int ssl3_get_record(SSL *s);
-static int do_compress(SSL *ssl);
-static int do_uncompress(SSL *ssl);
-static int do_change_cipher_spec(SSL *ssl);
 
-/* used only by ssl3_get_record */
-static int ssl3_read_n(SSL *s, int n, int max, int extend)
+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.
@@ -147,6 +141,14 @@ static int ssl3_read_n(SSL *s, int n, int max, int extend)
 		/* ... 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)
 		{
@@ -162,15 +164,13 @@ static int ssl3_read_n(SSL *s, int n, int max, int extend)
 
 	{
 		/* avoid buffer overflow */
-		int max_max = SSL3_RT_MAX_PACKET_SIZE - s->packet_length;
-		if (s->options & SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER)
-			max_max += SSL3_RT_MAX_EXTRA;
+		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,SSL_R_INTERNAL_ERROR);
+		SSLerr(SSL_F_SSL3_READ_N,ERR_R_INTERNAL_ERROR);
 		return -1;
 		}
 
@@ -231,14 +231,17 @@ static int ssl3_read_n(SSL *s, int n, int max, int extend)
 static int ssl3_get_record(SSL *s)
 	{
 	int ssl_major,ssl_minor,al;
-	int n,i,ret= -1;
+	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,extra;
+	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;
@@ -247,14 +250,20 @@ static int ssl3_get_record(SSL *s)
 		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,
-			SSL3_RT_MAX_PACKET_SIZE,0);
+		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;
 
@@ -266,6 +275,9 @@ again:
 		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)
@@ -291,8 +303,7 @@ again:
 			goto err;
 			}
 
-		if (rr->length > 
-			(unsigned int)SSL3_RT_MAX_ENCRYPTED_LENGTH+extra)
+		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);
@@ -304,7 +315,7 @@ again:
 
 	/* s->rstate == SSL_ST_READ_BODY, get and decode the data */
 
-	if (rr->length > (s->packet_length-SSL3_RT_HEADER_LENGTH))
+	if (rr->length > s->packet_length-SSL3_RT_HEADER_LENGTH)
 		{
 		/* now s->packet_length == SSL3_RT_HEADER_LENGTH */
 		i=rr->length;
@@ -332,7 +343,7 @@ again:
 	 * rr->length bytes of encrypted compressed stuff. */
 
 	/* check is not needed I believe */
-	if (rr->length > (unsigned int)SSL3_RT_MAX_ENCRYPTED_LENGTH+extra)
+	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);
@@ -342,16 +353,26 @@ again:
 	/* decrypt in place in 'rr->input' */
 	rr->data=rr->input;
 
-	if (!s->method->ssl3_enc->enc(s,0))
+	enc_err = s->method->ssl3_enc->enc(s,0);
+	if (enc_err <= 0)
 		{
-		al=SSL_AD_DECRYPT_ERROR;
-		goto f_err;
+		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) ||
@@ -364,39 +385,61 @@ printf("\n");
 
 		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)
+		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
 			}
-		rr->length-=mac_size;
 		i=s->method->ssl3_enc->mac(s,md,0);
-		if (memcmp(md,&(rr->data[rr->length]),mac_size) != 0)
+		if (mac == NULL || memcmp(md, mac, mac_size) != 0)
 			{
-			al=SSL_AD_BAD_RECORD_MAC;
-			SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_BAD_MAC_DECODE);
-			ret= -1;
-			goto f_err;
+			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 > 
-			(unsigned int)SSL3_RT_MAX_COMPRESSED_LENGTH+extra)
+		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 (!do_uncompress(s))
+		if (!ssl3_do_uncompress(s))
 			{
 			al=SSL_AD_DECOMPRESSION_FAILURE;
 			SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_BAD_DECOMPRESSION);
@@ -404,7 +447,7 @@ printf("\n");
 			}
 		}
 
-	if (rr->length > (unsigned int)SSL3_RT_MAX_PLAIN_LENGTH+extra)
+	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);
@@ -426,15 +469,21 @@ printf("\n");
 	/* 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);
 	}
 
-static int do_uncompress(SSL *ssl)
+int ssl3_do_uncompress(SSL *ssl)
 	{
+#ifndef OPENSSL_NO_COMP
 	int i;
 	SSL3_RECORD *rr;
 
@@ -446,12 +495,13 @@ static int do_uncompress(SSL *ssl)
 	else
 		rr->length=i;
 	rr->data=rr->comp;
-
+#endif
 	return(1);
 	}
 
-static int do_compress(SSL *ssl)
+int ssl3_do_compress(SSL *ssl)
 	{
+#ifndef OPENSSL_NO_COMP
 	int i;
 	SSL3_RECORD *wr;
 
@@ -465,6 +515,7 @@ static int do_compress(SSL *ssl)
 		wr->length=i;
 
 	wr->input=wr->data;
+#endif
 	return(1);
 	}
 
@@ -488,30 +539,34 @@ int ssl3_write_bytes(SSL *s, int type, const void *buf_, int len)
 		if (i == 0)
 			{
 			SSLerr(SSL_F_SSL3_WRITE_BYTES,SSL_R_SSL_HANDSHAKE_FAILURE);
-			return(-1);
+			return -1;
 			}
 		}
 
 	n=(len-tot);
 	for (;;)
 		{
-		if (n > SSL3_RT_MAX_PLAIN_LENGTH)
-			nw=SSL3_RT_MAX_PLAIN_LENGTH;
+		if (n > s->max_send_fragment)
+			nw=s->max_send_fragment;
 		else
 			nw=n;
 
-		i=do_ssl3_write(s,type,&(buf[tot]),nw);
+		i=do_ssl3_write(s, type, &(buf[tot]), nw, 0);
 		if (i <= 0)
 			{
 			s->s3->wnum=tot;
-			return(i);
+			return i;
 			}
 
 		if ((i == (int)n) ||
 			(type == SSL3_RT_APPLICATION_DATA &&
 			 (s->mode & SSL_MODE_ENABLE_PARTIAL_WRITE)))
 			{
-			return(tot+i);
+			/* 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;
@@ -520,15 +575,16 @@ int ssl3_write_bytes(SSL *s, int type, const void *buf_, int len)
 	}
 
 static int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
-			 unsigned int len)
+			 unsigned int len, int create_empty_fragment)
 	{
 	unsigned char *p,*plen;
 	int i,mac_size,clear=0;
+	int prefix_len = 0;
 	SSL3_RECORD *wr;
 	SSL3_BUFFER *wb;
 	SSL_SESSION *sess;
 
-	/* first check is there is a SSL3_RECORD still being written
+	/* first check if there is a SSL3_BUFFER still being written
 	 * out.  This will happen with non blocking IO */
 	if (s->s3->wbuf.left != 0)
 		return(ssl3_write_pending(s,type,buf,len));
@@ -536,13 +592,14 @@ static int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
 	/* If we have an alert to send, lets send it */
 	if (s->s3->alert_dispatch)
 		{
-		i=ssl3_dispatch_alert(s);
+		i=s->method->ssl_dispatch_alert(s);
 		if (i <= 0)
 			return(i);
 		/* if it went, fall through and send more stuff */
 		}
 
-	if (len == 0) return(len);
+	if (len == 0 && !create_empty_fragment)
+		return 0;
 
 	wr= &(s->s3->wrec);
 	wb= &(s->s3->wbuf);
@@ -558,16 +615,45 @@ static int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
 	else
 		mac_size=EVP_MD_size(s->write_hash);
 
-	p=wb->buf;
+	/* '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;
+		}
+
+	p = wb->buf + prefix_len;
 
 	/* write the header */
+
 	*(p++)=type&0xff;
 	wr->type=type;
 
 	*(p++)=(s->version>>8);
 	*(p++)=s->version&0xff;
 
-	/* record where we are to write out packet length */
+	/* field where we are to write out packet length */
 	plen=p; 
 	p+=2;
 
@@ -582,7 +668,7 @@ static int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
 	/* first we compress */
 	if (s->compress != NULL)
 		{
-		if (!do_compress(s))
+		if (!ssl3_do_compress(s))
 			{
 			SSLerr(SSL_F_DO_SSL3_WRITE,SSL_R_COMPRESSION_FAILURE);
 			goto err;
@@ -618,24 +704,33 @@ static int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
 	wr->type=type; /* not needed but helps for debugging */
 	wr->length+=SSL3_RT_HEADER_LENGTH;
 
-	/* Now lets setup wb */
-	wb->left=wr->length;
-	wb->offset=0;
+	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;
+	wb->offset = 0;
 
+	/* 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));
+	return ssl3_write_pending(s,type,buf,len);
 err:
-	return(-1);
+	return -1;
 	}
 
 /* if s->s3->wbuf.left != 0, we need to call this */
-static int ssl3_write_pending(SSL *s, int type, const unsigned char *buf,
-			      unsigned int len)
+int ssl3_write_pending(SSL *s, int type, const unsigned char *buf,
+	unsigned int len)
 	{
 	int i;
 
@@ -704,19 +799,21 @@ static int ssl3_write_pending(SSL *s, int type, const unsigned char *buf,
  *     Application data protocol
  *             none of our business
  */
-int ssl3_read_bytes(SSL *s, int type, unsigned char *buf, int len)
+int ssl3_read_bytes(SSL *s, int type, unsigned char *buf, int len, int peek)
 	{
-	int al,i,j,n,ret;
+	int al,i,j,ret;
+	unsigned int n;
 	SSL3_RECORD *rr;
-	void (*cb)()=NULL;
+	void (*cb)(const SSL *ssl,int type2,int val)=NULL;
 
 	if (s->s3->rbuf.buf == NULL) /* Not initialized yet */
 		if (!ssl3_setup_buffers(s))
 			return(-1);
 
-	if ((type != SSL3_RT_APPLICATION_DATA) && (type != SSL3_RT_HANDSHAKE) && type)
+	if ((type && (type != SSL3_RT_APPLICATION_DATA) && (type != SSL3_RT_HANDSHAKE) && type) ||
+	    (peek && (type != SSL3_RT_APPLICATION_DATA)))
 		{
-		SSLerr(SSL_F_SSL3_READ_BYTES, SSL_R_INTERNAL_ERROR);
+		SSLerr(SSL_F_SSL3_READ_BYTES, ERR_R_INTERNAL_ERROR);
 		return -1;
 		}
 
@@ -725,7 +822,9 @@ int ssl3_read_bytes(SSL *s, int type, unsigned char *buf, int len)
 		{
 		unsigned char *src = s->s3->handshake_fragment;
 		unsigned char *dst = buf;
+		unsigned int k;
 
+		/* peek == 0 */
 		n = 0;
 		while ((len > 0) && (s->s3->handshake_fragment_len > 0))
 			{
@@ -734,8 +833,8 @@ int ssl3_read_bytes(SSL *s, int type, unsigned char *buf, int len)
 			n++;
 			}
 		/* move any remaining fragment bytes: */
-		for (i = 0; i < s->s3->handshake_fragment_len; i++)
-			s->s3->handshake_fragment[i] = *src++;
+		for (k = 0; k < s->s3->handshake_fragment_len; k++)
+			s->s3->handshake_fragment[k] = *src++;
 		return n;
 	}
 
@@ -761,7 +860,7 @@ start:
 	 * s->s3->rrec.length,  - number of bytes. */
 	rr = &(s->s3->rrec);
 
-	/* get new packet */
+	/* get new packet if necessary */
 	if ((rr->length == 0) || (s->rstate == SSL_ST_READ_BODY))
 		{
 		ret=ssl3_get_record(s);
@@ -776,10 +875,11 @@ start:
 		{
 		al=SSL_AD_UNEXPECTED_MESSAGE;
 		SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_DATA_BETWEEN_CCS_AND_FINISHED);
-		goto err;
+		goto f_err;
 		}
 
-	/* If the other end has shutdown, throw anything we read away */
+	/* If the other end has shut down, throw anything we read away
+	 * (even in 'peek' mode) */
 	if (s->shutdown & SSL_RECEIVED_SHUTDOWN)
 		{
 		rr->length=0;
@@ -803,17 +903,20 @@ start:
 		if (len <= 0) return(len);
 
 		if ((unsigned int)len > rr->length)
-			n=rr->length;
+			n = rr->length;
 		else
-			n=len;
+			n = (unsigned int)len;
 
-		memcpy(buf,&(rr->data[rr->off]),(unsigned int)n);
-		rr->length-=n;
-		rr->off+=n;
-		if (rr->length == 0)
+		memcpy(buf,&(rr->data[rr->off]),n);
+		if (!peek)
 			{
-			s->rstate=SSL_ST_READ_HEADER;
-			rr->off=0;
+			rr->length-=n;
+			rr->off+=n;
+			if (rr->length == 0)
+				{
+				s->rstate=SSL_ST_READ_HEADER;
+				rr->off=0;
+				}
 			}
 		return(n);
 		}
@@ -826,9 +929,9 @@ start:
 	 * fill that so that we can process the data at a fixed place.
 	 */
 		{
-		int dest_maxlen = 0;
-		unsigned char *dest;
-		int *dest_len;
+		unsigned int dest_maxlen = 0;
+		unsigned char *dest = NULL;
+		unsigned int *dest_len = NULL;
 
 		if (rr->type == SSL3_RT_HANDSHAKE)
 			{
@@ -879,9 +982,12 @@ start:
 			{
 			al=SSL_AD_DECODE_ERROR;
 			SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_BAD_HELLO_REQUEST);
-			goto err;
+			goto f_err;
 			}
 
+		if (s->msg_callback)
+			s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, s->s3->handshake_fragment, 4, s, s->msg_callback_arg);
+
 		if (SSL_is_init_finished(s) &&
 			!(s->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS) &&
 			!s->s3->renegotiate)
@@ -889,27 +995,29 @@ start:
 			ssl3_renegotiate(s);
 			if (ssl3_renegotiate_check(s))
 				{
-				n=s->handshake_func(s);
-				if (n < 0) return(n);
-				if (n == 0)
+				i=s->handshake_func(s);
+				if (i < 0) return(i);
+				if (i == 0)
 					{
 					SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_SSL_HANDSHAKE_FAILURE);
 					return(-1);
 					}
 
-				if (s->s3->rbuf.left == 0) /* no read-ahead left? */
+				if (!(s->mode & SSL_MODE_AUTO_RETRY))
 					{
-					BIO *bio;
-					/* In the case where we try to read application data
-					 * the first time, but we trigger an SSL handshake, we
-					 * return -1 with the retry option set.  I do this
-					 * otherwise renegotiation can cause nasty problems 
-					 * in the blocking world */ /* ? */
-					s->rwstate=SSL_READING;
-					bio=SSL_get_rbio(s);
-					BIO_clear_retry_flags(bio);
-					BIO_set_retry_read(bio);
-					return(-1);
+					if (s->s3->rbuf.left == 0) /* no read-ahead left? */
+						{
+						BIO *bio;
+						/* In the case where we try to read application data,
+						 * but we trigger an SSL handshake, we return -1 with
+						 * the retry option set.  Otherwise renegotiation may
+						 * cause nasty problems in the blocking world */
+						s->rwstate=SSL_READING;
+						bio=SSL_get_rbio(s);
+						BIO_clear_retry_flags(bio);
+						BIO_set_retry_read(bio);
+						return(-1);
+						}
 					}
 				}
 			}
@@ -920,11 +1028,14 @@ start:
 
 	if (s->s3->alert_fragment_len >= 2)
 		{
-		i = s->s3->alert_fragment[0];
-		n = s->s3->alert_fragment[1];
+		int alert_level = s->s3->alert_fragment[0];
+		int alert_descr = s->s3->alert_fragment[1];
 
 		s->s3->alert_fragment_len = 0;
 
+		if (s->msg_callback)
+			s->msg_callback(0, s->version, SSL3_RT_ALERT, s->s3->alert_fragment, 2, s, s->msg_callback_arg);
+
 		if (s->info_callback != NULL)
 			cb=s->info_callback;
 		else if (s->ctx->info_callback != NULL)
@@ -932,28 +1043,27 @@ start:
 
 		if (cb != NULL)
 			{
-			j=(i<<8)|n;
-			cb(s,SSL_CB_READ_ALERT,j);
+			j = (alert_level << 8) | alert_descr;
+			cb(s, SSL_CB_READ_ALERT, j);
 			}
 
-		if (i == 1) /* warning */
+		if (alert_level == 1) /* warning */
 			{
-			s->s3->warn_alert=n;
-			if (n == SSL_AD_CLOSE_NOTIFY)
+			s->s3->warn_alert = alert_descr;
+			if (alert_descr == SSL_AD_CLOSE_NOTIFY)
 				{
-				s->shutdown|=SSL_RECEIVED_SHUTDOWN;
+				s->shutdown |= SSL_RECEIVED_SHUTDOWN;
 				return(0);
 				}
 			}
-		else if (i == 2) /* fatal */
+		else if (alert_level == 2) /* fatal */
 			{
 			char tmp[16];
 
 			s->rwstate=SSL_NOTHING;
-			s->s3->fatal_alert=n;
-			SSLerr(SSL_F_SSL3_READ_BYTES,
-				SSL_AD_REASON_OFFSET+n);
-			sprintf(tmp,"%d",n);
+			s->s3->fatal_alert = alert_descr;
+			SSLerr(SSL_F_SSL3_READ_BYTES, SSL_AD_REASON_OFFSET + alert_descr);
+			BIO_snprintf(tmp,sizeof tmp,"%d",alert_descr);
 			ERR_add_error_data(2,"SSL alert number ",tmp);
 			s->shutdown|=SSL_RECEIVED_SHUTDOWN;
 			SSL_CTX_remove_session(s->ctx,s->session);
@@ -983,14 +1093,26 @@ start:
 		if (	(rr->length != 1) || (rr->off != 0) ||
 			(rr->data[0] != SSL3_MT_CCS))
 			{
-			i=SSL_AD_ILLEGAL_PARAMETER;
+			al=SSL_AD_ILLEGAL_PARAMETER;
 			SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_BAD_CHANGE_CIPHER_SPEC);
-			goto err;
+			goto f_err;
+			}
+
+		/* Check we have a cipher to change to */
+		if (s->s3->tmp.new_cipher == NULL)
+			{
+			al=SSL_AD_UNEXPECTED_MESSAGE;
+			SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_CCS_RECEIVED_EARLY);
+			goto f_err;
 			}
 
 		rr->length=0;
+
+		if (s->msg_callback)
+			s->msg_callback(0, s->version, SSL3_RT_CHANGE_CIPHER_SPEC, rr->data, 1, s, s->msg_callback_arg);
+
 		s->s3->change_cipher_spec=1;
-		if (!do_change_cipher_spec(s))
+		if (!ssl3_do_change_cipher_spec(s))
 			goto err;
 		else
 			goto start;
@@ -1013,27 +1135,29 @@ start:
 #endif
 			s->new_session=1;
 			}
-		n=s->handshake_func(s);
-		if (n < 0) return(n);
-		if (n == 0)
+		i=s->handshake_func(s);
+		if (i < 0) return(i);
+		if (i == 0)
 			{
 			SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_SSL_HANDSHAKE_FAILURE);
 			return(-1);
 			}
 
-		if (s->s3->rbuf.left == 0) /* no read-ahead left? */
+		if (!(s->mode & SSL_MODE_AUTO_RETRY))
 			{
-			BIO *bio;
-			/* In the case where we try to read application data
-			 * the first time, but we trigger an SSL handshake, we
-			 * return -1 with the retry option set.  I do this
-			 * otherwise renegotiation can cause nasty problems 
-			 * in the blocking world */ /* ? */
-			s->rwstate=SSL_READING;
-			bio=SSL_get_rbio(s);
-			BIO_clear_retry_flags(bio);
-			BIO_set_retry_read(bio);
-			return(-1);
+			if (s->s3->rbuf.left == 0) /* no read-ahead left? */
+				{
+				BIO *bio;
+				/* In the case where we try to read application data,
+				 * but we trigger an SSL handshake, we return -1 with
+				 * the retry option set.  Otherwise renegotiation may
+				 * cause nasty problems in the blocking world */
+				s->rwstate=SSL_READING;
+				bio=SSL_get_rbio(s);
+				BIO_clear_retry_flags(bio);
+				BIO_set_retry_read(bio);
+				return(-1);
+				}
 			}
 		goto start;
 		}
@@ -1041,10 +1165,11 @@ start:
 	switch (rr->type)
 		{
 	default:
-#ifndef NO_TLS
+#ifndef OPENSSL_NO_TLS
 		/* TLS just ignores unknown message types */
 		if (s->version == TLS1_VERSION)
 			{
+			rr->length = 0;
 			goto start;
 			}
 #endif
@@ -1058,7 +1183,7 @@ start:
 		 * of SSL3_RT_HANDSHAKE when s->in_handshake is set, but that
 		 * should not happen when type != rr->type */
 		al=SSL_AD_UNEXPECTED_MESSAGE;
-		SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_INTERNAL_ERROR);
+		SSLerr(SSL_F_SSL3_READ_BYTES,ERR_R_INTERNAL_ERROR);
 		goto f_err;
 	case SSL3_RT_APPLICATION_DATA:
 		/* At this point, we were expecting handshake data,
@@ -1081,7 +1206,7 @@ start:
 					)
 				))
 			{
-			s->s3->in_read_app_data=0;
+			s->s3->in_read_app_data=2;
 			return(-1);
 			}
 		else
@@ -1099,7 +1224,7 @@ err:
 	return(-1);
 	}
 
-static int do_change_cipher_spec(SSL *s)
+int ssl3_do_change_cipher_spec(SSL *s)
 	{
 	int i;
 	const char *sender;
@@ -1145,6 +1270,8 @@ void ssl3_send_alert(SSL *s, int level, int desc)
 	{
 	/* Map tls/ssl alert value to correct one */
 	desc=s->method->ssl3_enc->alert_value(desc);
+	if (s->version == SSL3_VERSION && desc == SSL_AD_PROTOCOL_VERSION)
+		desc = SSL_AD_HANDSHAKE_FAILURE; /* SSL 3.0 does not have protocol_version alerts */
 	if (desc < 0) return;
 	/* If a fatal one, remove from cache */
 	if ((level == 2) && (s->session != NULL))
@@ -1153,8 +1280,8 @@ void ssl3_send_alert(SSL *s, int level, int desc)
 	s->s3->alert_dispatch=1;
 	s->s3->send_alert[0]=level;
 	s->s3->send_alert[1]=desc;
-	if (s->s3->wbuf.left == 0) /* data still being written out */
-		ssl3_dispatch_alert(s);
+	if (s->s3->wbuf.left == 0) /* data still being written out? */
+		s->method->ssl_dispatch_alert(s);
 	/* else data is still being written out, we will get written
 	 * some time in the future */
 	}
@@ -1162,22 +1289,25 @@ void ssl3_send_alert(SSL *s, int level, int desc)
 int ssl3_dispatch_alert(SSL *s)
 	{
 	int i,j;
-	void (*cb)()=NULL;
+	void (*cb)(const SSL *ssl,int type,int val)=NULL;
 
 	s->s3->alert_dispatch=0;
-	i=do_ssl3_write(s,SSL3_RT_ALERT,&s->s3->send_alert[0],2);
+	i = do_ssl3_write(s, SSL3_RT_ALERT, &s->s3->send_alert[0], 2, 0);
 	if (i <= 0)
 		{
 		s->s3->alert_dispatch=1;
 		}
 	else
 		{
-		/* If it is important, send it now.  If the message
-		 * does not get sent due to non-blocking IO, we will
-		 * not worry too much. */
+		/* Alert sent to BIO.  If it is important, flush it now.
+		 * If the message does not get sent due to non-blocking IO,
+		 * we will not worry too much. */
 		if (s->s3->send_alert[0] == SSL3_AL_FATAL)
 			(void)BIO_flush(s->wbio);
 
+		if (s->msg_callback)
+			s->msg_callback(1, s->version, SSL3_RT_ALERT, s->s3->send_alert, 2, s, s->msg_callback_arg);
+
 		if (s->info_callback != NULL)
 			cb=s->info_callback;
 		else if (s->ctx->info_callback != NULL)