DTLS revision.

Revise DTLS code. There was a *lot* of code duplication in the
DTLS code that generates records. This makes it harder to maintain and
sometimes a TLS update is omitted by accident from the DTLS code.

Specifically almost all of the record generation functions have code like
this:

some_pointer = buffer + HANDSHAKE_HEADER_LENGTH;
... Record creation stuff ...
set_handshake_header(ssl, SSL_MT_SOMETHING, message_len);

...

write_handshake_message(ssl);

Where the "Record creation stuff" is identical between SSL/TLS and DTLS or
in some cases has very minor differences.

By adding a few fields to SSL3_ENC to include the header length, some flags
and function pointers for handshake header setting and handshake writing the
code can cope with both cases.

(cherry picked from commit 173e72e64c6a07ae97660c322396b66215009f33)

1 files changed, 52 insertions, 38 deletions

diff --git a/ssl/s3_clnt.c b/ssl/s3_clnt.c
index 61b0cdc204..88384bf5da 100644
--- a/ssl/s3_clnt.c
+++ b/ssl/s3_clnt.c
@@ -697,13 +697,34 @@ int ssl3_client_hello(SSL *s)
 		/* else use the pre-loaded session */
 
 		p=s->s3->client_random;
-		Time=(unsigned long)time(NULL);			/* Time */
-		l2n(Time,p);
-		if (RAND_pseudo_bytes(p,SSL3_RANDOM_SIZE-4) <= 0)
-			goto err;
+
+		/* for DTLS if client_random is initialized, reuse it, we are
+		 * required to use same upon reply to HelloVerify */
+		if (SSL_IS_DTLS(s))
+			{
+			size_t idx;
+			i = 1;
+			for (idx=0; idx < sizeof(s->s3->client_random); idx++)
+				{
+				if (p[idx])
+					{
+					i = 0;
+					break;
+					}
+				}
+			}
+		else 
+			i = 1;
+
+		if (i)
+			{
+			Time=(unsigned long)time(NULL);	/* Time */
+			l2n(Time,p);
+			RAND_pseudo_bytes(p,sizeof(s->s3->client_random)-4);
+			}
 
 		/* Do the message type and length last */
-		d=p= &(buf[4]);
+		d=p= ssl_handshake_start(s);
 
 		/* version indicates the negotiated version: for example from
 		 * an SSLv2/v3 compatible client hello). The client_version
@@ -764,6 +785,19 @@ int ssl3_client_hello(SSL *s)
 			p+=i;
 			}
 		
+		/* cookie stuff for DTLS */
+		if (SSL_IS_DTLS(s))
+			{
+			if ( s->d1->cookie_len > sizeof(s->d1->cookie))
+				{
+				SSLerr(SSL_F_SSL3_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
+				goto err;
+				}
+			*(p++) = s->d1->cookie_len;
+			memcpy(p, s->d1->cookie, s->d1->cookie_len);
+			p += s->d1->cookie_len;
+			}
+		
 		/* Ciphers supported */
 		i=ssl_cipher_list_to_bytes(s,SSL_get_ciphers(s),&(p[2]),0);
 		if (i == 0)
@@ -816,19 +850,13 @@ int ssl3_client_hello(SSL *s)
 			}
 #endif
 		
-		l=(p-d);
-		d=buf;
-		*(d++)=SSL3_MT_CLIENT_HELLO;
-		l2n3(l,d);
-
+		l= p-d;
+		ssl_set_handshake_header(s, SSL3_MT_CLIENT_HELLO, l);
 		s->state=SSL3_ST_CW_CLNT_HELLO_B;
-		/* number of bytes to write */
-		s->init_num=p-buf;
-		s->init_off=0;
 		}
 
 	/* SSL3_ST_CW_CLNT_HELLO_B */
-	return(ssl3_do_write(s,SSL3_RT_HANDSHAKE));
+	return ssl_do_write(s);
 err:
 	return(-1);
 	}
@@ -2261,7 +2289,7 @@ int ssl3_get_server_done(SSL *s)
 
 int ssl3_send_client_key_exchange(SSL *s)
 	{
-	unsigned char *p,*d;
+	unsigned char *p;
 	int n;
 	unsigned long alg_k;
 #ifndef OPENSSL_NO_RSA
@@ -2282,8 +2310,7 @@ int ssl3_send_client_key_exchange(SSL *s)
 
 	if (s->state == SSL3_ST_CW_KEY_EXCH_A)
 		{
-		d=(unsigned char *)s->init_buf->data;
-		p= &(d[4]);
+		p = ssl_handshake_start(s);
 
 		alg_k=s->s3->tmp.new_cipher->algorithm_mkey;
 
@@ -2984,18 +3011,13 @@ int ssl3_send_client_key_exchange(SSL *s)
 			    ERR_R_INTERNAL_ERROR);
 			goto err;
 			}
-		
-		*(d++)=SSL3_MT_CLIENT_KEY_EXCHANGE;
-		l2n3(n,d);
 
+		ssl_set_handshake_header(s, SSL3_MT_CLIENT_KEY_EXCHANGE, n);
 		s->state=SSL3_ST_CW_KEY_EXCH_B;
-		/* number of bytes to write */
-		s->init_num=n+4;
-		s->init_off=0;
 		}
 
 	/* SSL3_ST_CW_KEY_EXCH_B */
-	return(ssl3_do_write(s,SSL3_RT_HANDSHAKE));
+	return ssl_do_write(s);
 err:
 #ifndef OPENSSL_NO_ECDH
 	BN_CTX_free(bn_ctx);
@@ -3009,7 +3031,7 @@ err:
 
 int ssl3_send_client_verify(SSL *s)
 	{
-	unsigned char *p,*d;
+	unsigned char *p;
 	unsigned char data[MD5_DIGEST_LENGTH+SHA_DIGEST_LENGTH];
 	EVP_PKEY *pkey;
 	EVP_PKEY_CTX *pctx=NULL;
@@ -3022,8 +3044,7 @@ int ssl3_send_client_verify(SSL *s)
 
 	if (s->state == SSL3_ST_CW_CERT_VRFY_A)
 		{
-		d=(unsigned char *)s->init_buf->data;
-		p= &(d[4]);
+		p= ssl_handshake_start(s);
 		pkey=s->cert->key->privatekey;
 /* Create context from key and test if sha1 is allowed as digest */
 		pctx = EVP_PKEY_CTX_new(pkey,NULL);
@@ -3149,16 +3170,12 @@ int ssl3_send_client_verify(SSL *s)
 			SSLerr(SSL_F_SSL3_SEND_CLIENT_VERIFY,ERR_R_INTERNAL_ERROR);
 			goto err;
 		}
-		*(d++)=SSL3_MT_CERTIFICATE_VERIFY;
-		l2n3(n,d);
-
+		ssl_set_handshake_header(s, SSL3_MT_CERTIFICATE_VERIFY, n);
 		s->state=SSL3_ST_CW_CERT_VRFY_B;
-		s->init_num=(int)n+4;
-		s->init_off=0;
 		}
 	EVP_MD_CTX_cleanup(&mctx);
 	EVP_PKEY_CTX_free(pctx);
-	return(ssl3_do_write(s,SSL3_RT_HANDSHAKE));
+	return ssl_do_write(s);
 err:
 	EVP_MD_CTX_cleanup(&mctx);
 	EVP_PKEY_CTX_free(pctx);
@@ -3215,7 +3232,6 @@ int ssl3_send_client_certificate(SSL *s)
 	X509 *x509=NULL;
 	EVP_PKEY *pkey=NULL;
 	int i;
-	unsigned long l;
 
 	if (s->state ==	SSL3_ST_CW_CERT_A)
 		{
@@ -3284,13 +3300,11 @@ int ssl3_send_client_certificate(SSL *s)
 	if (s->state == SSL3_ST_CW_CERT_C)
 		{
 		s->state=SSL3_ST_CW_CERT_D;
-		l=ssl3_output_cert_chain(s,
+		ssl3_output_cert_chain(s,
 			(s->s3->tmp.cert_req == 2)?NULL:s->cert->key);
-		s->init_num=(int)l;
-		s->init_off=0;
 		}
 	/* SSL3_ST_CW_CERT_D */
-	return(ssl3_do_write(s,SSL3_RT_HANDSHAKE));
+	return ssl_do_write(s);
 	}
 
 #define has_bits(i,m)	(((i)&(m)) == (m))