Update ssl library to support EVP_PKEY MAC API. Include generic MAC support.
[openssl.git] / ssl / s3_pkt.c
index e411fb5a0380b5f180a84df9fa844df19b50d3b5..58f2845d6e024f070074921adb152a537f906b3d 100644 (file)
 #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, int create_empty_fragment);
-static int ssl3_write_pending(SSL *s, int type, const unsigned char *buf,
-                             unsigned int len);
 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.
@@ -135,65 +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 = s->s3->rbuf.len - s->packet_length;
-               if (max > max_max)
-                       max = max_max;
-       }
+       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 */
+               {
+               memmove(pkt, s->packet, len+left);
+               s->packet = pkt;
+               rb->offset = len + align;
+               }
+
+       max = rb->len - rb->offset;
        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;
-               }
+       if (!s->read_ahead)
+               max=n;
 
-       while (newb < 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
                        {
@@ -203,15 +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);
@@ -236,7 +265,10 @@ static int ssl3_get_record(SSL *s)
        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;
@@ -245,9 +277,9 @@ static int ssl3_get_record(SSL *s)
                extra=SSL3_RT_MAX_EXTRA;
        else
                extra=0;
-       if ((size_t)extra != (s->s3->rbuf.len - SSL3_RT_MAX_PACKET_SIZE))
+       if (extra && !s->s3->init_extra)
                {
-               /* actually likely an application error: SLS_OP_MICROSOFT_BIG_SSLV3_BUFFER
+               /* 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;
@@ -270,13 +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)
                                {
@@ -295,8 +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);
@@ -308,7 +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;
@@ -336,7 +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);
@@ -353,8 +383,11 @@ again:
                        /* SSLerr() and ssl3_send_alert() have been called */
                        goto err;
 
-               /* otherwise enc_err == -1 */
-               goto decryption_failed_or_bad_record_mac;
+               /* 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
@@ -366,12 +399,12 @@ printf("\n");
        /* 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)
                        {
@@ -380,39 +413,56 @@ printf("\n");
                        SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_PRE_MAC_LENGTH_TOO_LONG);
                        goto f_err;
 #else
-                       goto decryption_failed_or_bad_record_mac;
+                       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
-                       goto decryption_failed_or_bad_record_mac;
+                       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)
                        {
-                       goto decryption_failed_or_bad_record_mac;
+                       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);
@@ -420,7 +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);
@@ -442,24 +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);
 
-decryption_failed_or_bad_record_mac:
-       /* 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 logfile) */
-       al=SSL_AD_BAD_RECORD_MAC;
-       SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC);
 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;
 
@@ -471,12 +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;
 
@@ -490,6 +538,7 @@ static int do_compress(SSL *ssl)
                wr->length=i;
 
        wr->input=wr->data;
+#endif
        return(1);
        }
 
@@ -520,8 +569,8 @@ int ssl3_write_bytes(SSL *s, int type, const void *buf_, int len)
        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;
 
@@ -553,20 +602,20 @@ static int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
        {
        unsigned char *p,*plen;
        int i,mac_size,clear=0;
-       int prefix_len = 0;
+       int prefix_len=0,align=0;
        SSL3_RECORD *wr;
-       SSL3_BUFFER *wb;
+       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 (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 */
@@ -576,18 +625,17 @@ static int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
                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);
 
        /* 'create_empty_fragment' is true only when this function calls itself */
        if (!clear && !create_empty_fragment && !s->s3->empty_fragment_done)
@@ -605,7 +653,8 @@ static int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
                        if (prefix_len <= 0)
                                goto err;
 
-                       if (s->s3->wbuf.len < (size_t)prefix_len + SSL3_RT_MAX_PACKET_SIZE)
+                       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);
@@ -616,7 +665,32 @@ static int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
                s->s3->empty_fragment_done = 1;
                }
 
-       p = wb->buf + prefix_len;
+       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 */
 
@@ -641,7 +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;
@@ -687,7 +761,6 @@ static int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
 
        /* 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;
@@ -702,10 +775,11 @@ err:
        }
 
 /* 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)
@@ -724,24 +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;
                }
        }
 
@@ -848,7 +923,7 @@ 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 shut down, throw anything we read away
@@ -955,7 +1030,7 @@ 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)
@@ -1066,9 +1141,17 @@ 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;
@@ -1077,7 +1160,7 @@ start:
                        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;
@@ -1189,7 +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;
@@ -1246,7 +1329,7 @@ void ssl3_send_alert(SSL *s, int level, int desc)
        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);
+               s->method->ssl_dispatch_alert(s);
        /* else data is still being written out, we will get written
         * some time in the future */
        }