Update ssl library to support EVP_PKEY MAC API. Include generic MAC support.
[openssl.git] / ssl / s3_pkt.c
index fd344c4ceb1e45786f3fee881689989b1e75ae55..58f2845d6e024f070074921adb152a537f906b3d 100644 (file)
@@ -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
 #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.
@@ -135,67 +129,100 @@ static int ssl3_read_n(SSL *s, int n, int max, int extend)
         * (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;
+       int i,len,left,align=0;
+       unsigned char *pkt;
+       SSL3_BUFFER *rb;
+
+       if (n <= 0) return n;
+
+       rb    = &(s->s3->rbuf);
+       left  = rb->left;
+#if defined(SSL3_ALIGN_PAYLOAD) && SSL3_ALIGN_PAYLOAD!=0
+       align = (int)rb->buf + SSL3_RT_HEADER_LENGTH;
+       align = (-align)&(SSL3_ALIGN_PAYLOAD-1);
+#endif
 
        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;
+               if (left == 0)
+                       rb->offset = align;
+               else if (align != 0 && left >= SSL3_RT_HEADER_LENGTH)
+                       {
+                       /* check if next packet length is large
+                        * enough to justify payload alignment... */
+                       pkt = rb->buf + rb->offset;
+                       if (pkt[0] == SSL3_RT_APPLICATION_DATA
+                           && (pkt[3]<<8|pkt[4]) >= 128)
+                               {
+                               /* Note that even if packet is corrupted
+                                * and its length field is insane, we can
+                                * only be led to wrong decision about
+                                * whether memmove will occur or not.
+                                * Header values has no effect on memmove
+                                * arguments and therefore no buffer
+                                * overrun can be triggered. */
+                               memmove (rb->buf+align,pkt,left);
+                               rb->offset = align;
+                               }
+                       }
+               s->packet = rb->buf + rb->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 ( left > 0 && n > left)
+                       n = left;
+               }
+
        /* if there is enough in the buffer from a previous read, take some */
-       if (s->s3->rbuf.left >= (int)n)
+       if (left >= n)
                {
                s->packet_length+=n;
-               s->s3->rbuf.left-=n;
-               s->s3->rbuf.offset+=n;
+               rb->left=left-n;
+               rb->offset+=n;
                return(n);
                }
 
        /* else we need to read more data */
-       if (!s->read_ahead)
-               max=n;
 
-       {
-               /* 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;
-               if (max > max_max)
-                       max = max_max;
-       }
-       if (n > max) /* does not happen */
+       len = s->packet_length;
+       pkt = rb->buf+align;
+       /* Move any available bytes to front of buffer:
+        * 'len' bytes already pointed to by 'packet',
+        * 'left' extra ones at the end */
+       if (s->packet != pkt) /* len > 0 */
                {
-               SSLerr(SSL_F_SSL3_READ_N,SSL_R_INTERNAL_ERROR);
-               return -1;
+               memmove(pkt, s->packet, len+left);
+               s->packet = pkt;
+               rb->offset = len + align;
                }
 
-       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)
+       max = rb->len - rb->offset;
+       if (n > max) /* does not happen */
                {
-               /*  off > 0 */
-               memmove(s->s3->rbuf.buf, s->packet, off+newb);
-               s->packet = s->s3->rbuf.buf;
+               SSLerr(SSL_F_SSL3_READ_N,ERR_R_INTERNAL_ERROR);
+               return -1;
                }
 
-       while (newb < n)
+       if (!s->read_ahead)
+               max=n;
+
+       while (left < 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) */
+               /* Now we have len+left bytes at the front of s->s3->rbuf.buf
+                * and need to read in more until we have len+n (up to
+                * len+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);
+                       i=BIO_read(s->rbio,pkt+len+left, max-left);
                        }
                else
                        {
@@ -205,15 +232,15 @@ static int ssl3_read_n(SSL *s, int n, int max, int extend)
 
                if (i <= 0)
                        {
-                       s->s3->rbuf.left = newb;
+                       rb->left = left;
                        return(i);
                        }
-               newb+=i;
+               left+=i;
                }
 
        /* done reading, now the book-keeping */
-       s->s3->rbuf.offset = off + n;
-       s->s3->rbuf.left = newb - n;
+       rb->offset += n;
+       rb->left = left - n;
        s->packet_length += n;
        s->rwstate=SSL_NOTHING;
        return(n);
@@ -231,14 +258,17 @@ 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 +277,20 @@ 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;
 
@@ -266,13 +302,12 @@ 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)
-                       {
-                       s->first_packet=0;
-                       }
-               else
+               if (!s->first_packet)
                        {
                        if (version != s->version)
                                {
@@ -291,8 +326,7 @@ 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 +338,7 @@ 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 +366,7 @@ 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);
@@ -342,61 +376,93 @@ 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) ||
-               (s->read_hash == NULL))
+               (EVP_MD_CTX_md(s->read_hash) == NULL))
                clear=1;
 
        if (!clear)
                {
-               mac_size=EVP_MD_size(s->read_hash);
+               mac_size=EVP_MD_CTX_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)
+               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 +470,7 @@ 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 +492,21 @@ 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 +518,13 @@ 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 +538,7 @@ static int do_compress(SSL *ssl)
                wr->length=i;
 
        wr->input=wr->data;
+#endif
        return(1);
        }
 
@@ -488,30 +562,34 @@ 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;
@@ -520,54 +598,109 @@ 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,align=0;
        SSL3_RECORD *wr;
-       SSL3_BUFFER *wb;
+       SSL3_BUFFER *wb=&(s->s3->wbuf);
        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)
+       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=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);
        sess=s->session;
 
        if (    (sess == NULL) ||
                (s->enc_write_ctx == NULL) ||
-               (s->write_hash == NULL))
+               (EVP_MD_CTX_md(s->write_hash) == NULL))
                clear=1;
 
        if (clear)
                mac_size=0;
        else
-               mac_size=EVP_MD_size(s->write_hash);
+               mac_size=EVP_MD_CTX_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;
+               }
+
+       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 = (int)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 = (int)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);
        *(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 +715,7 @@ 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;
@@ -618,26 +751,35 @@ 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;
 
+       /* 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;
+       SSL3_BUFFER *wb=&(s->s3->wbuf);
 
 /* XXXX */
        if ((s->s3->wpend_tot > (int)len)
@@ -656,24 +798,25 @@ static int ssl3_write_pending(SSL *s, int type, const unsigned char *buf,
                        {
                        s->rwstate=SSL_WRITING;
                        i=BIO_write(s->wbio,
-                               (char *)&(s->s3->wbuf.buf[s->s3->wbuf.offset]),
-                               (unsigned int)s->s3->wbuf.left);
+                               (char *)&(wb->buf[wb->offset]),
+                               (unsigned int)wb->left);
                        }
                else
                        {
                        SSLerr(SSL_F_SSL3_WRITE_PENDING,SSL_R_BIO_NOT_SET);
                        i= -1;
                        }
-               if (i == s->s3->wbuf.left)
+               if (i == wb->left)
                        {
-                       s->s3->wbuf.left=0;
+                       wb->left=0;
+                       wb->offset+=i;
                        s->rwstate=SSL_NOTHING;
                        return(s->s3->wpend_ret);
                        }
                else if (i <= 0)
                        return(i);
-               s->s3->wbuf.offset+=i;
-               s->s3->wbuf.left-=i;
+               wb->offset+=i;
+               wb->left-=i;
                }
        }
 
@@ -704,19 +847,21 @@ 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 +870,9 @@ 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 +881,8 @@ 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 +908,7 @@ 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 +923,11 @@ 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 +951,20 @@ 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 +977,9 @@ 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 +1030,12 @@ 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 +1043,29 @@ 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 +1076,14 @@ 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 +1091,27 @@ 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 +1141,26 @@ 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 +1183,29 @@ 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 +1213,11 @@ 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 +1231,7 @@ 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 +1254,7 @@ start:
                                        )
                                ))
                        {
-                       s->s3->in_read_app_data=0;
+                       s->s3->in_read_app_data=2;
                        return(-1);
                        }
                else
@@ -1099,7 +1272,7 @@ 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 +1318,8 @@ 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 +1328,8 @@ 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 +1337,25 @@ 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)