X-Git-Url: https://git.openssl.org/gitweb/?p=openssl.git;a=blobdiff_plain;f=ssl%2Fd1_pkt.c;h=aefd85d0c3516948d381c6c69423a5234014596a;hp=5fe1321fcad2ffe9aa31b6f7c9b7058d6daa1b11;hb=cb2182676bdf652070bc272a3896d957763a4324;hpb=7e159e0133d28bec9148446e8f4dd86c0216d819

diff --git a/ssl/d1_pkt.c b/ssl/d1_pkt.c
index 5fe1321fca..aefd85d0c3 100644
--- a/ssl/d1_pkt.c
+++ b/ssl/d1_pkt.c
@@ -179,7 +179,6 @@ static int dtls1_record_needs_buffering(SSL *s, SSL3_RECORD *rr,
 static int dtls1_buffer_record(SSL *s, record_pqueue *q,
 	unsigned char *priority);
 static int dtls1_process_record(SSL *s);
-static void dtls1_clear_timeouts(SSL *s);
 
 /* copy buffered record into SSL structure */
 static int
@@ -377,14 +376,12 @@ static int
 dtls1_process_record(SSL *s)
 {
 	int i,al;
-	int clear=0;
 	int enc_err;
 	SSL_SESSION *sess;
 	SSL3_RECORD *rr;
 	unsigned int mac_size;
 	unsigned char md[EVP_MAX_MD_SIZE];
 
-
 	rr= &(s->s3->rrec);
 	sess = s->session;
 
@@ -413,16 +410,18 @@ dtls1_process_record(SSL *s)
 
 	/* decrypt in place in 'rr->input' */
 	rr->data=rr->input;
+	rr->orig_len=rr->length;
 
 	enc_err = s->method->ssl3_enc->enc(s,0);
-	if (enc_err <= 0)
+	/* enc_err is:
+	 *    0: (in non-constant time) if the record is publically invalid.
+	 *    1: if the padding is valid
+	 *    -1: if the padding is invalid */
+	if (enc_err == 0)
 		{
-		/* decryption failed, silently discard message */
-		if (enc_err < 0)
-			{
-			rr->length = 0;
-			s->packet_length = 0;
-			}
+		/* For DTLS we simply ignore bad packets. */
+		rr->length = 0;
+		s->packet_length = 0;
 		goto err;
 		}
 
@@ -433,46 +432,64 @@ printf("\n");
 #endif
 
 	/* r->length is now the compressed data plus mac */
-	if (	(sess == NULL) ||
-		(s->enc_read_ctx == NULL) ||
-		(s->read_hash == NULL))
-		clear=1;
-
-	if (!clear)
+	if ((sess != NULL) &&
+	    (s->enc_read_ctx != NULL) &&
+	    (EVP_MD_CTX_md(s->read_hash) != NULL))
 		{
-		/* !clear => s->read_hash != NULL => mac_size != -1 */
-		int t;
-		t=EVP_MD_CTX_size(s->read_hash);
-		OPENSSL_assert(t >= 0);
-		mac_size=t;
-
-		if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+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_DTLS1_PROCESS_RECORD,SSL_R_PRE_MAC_LENGTH_TOO_LONG);
-			goto f_err;
-#else
-			goto err;
-#endif			
-			}
-		/* check the MAC for rr->input (it's in mac_size bytes at the tail) */
-		if (rr->length < mac_size)
+		/* s->read_hash != NULL => mac_size != -1 */
+		unsigned char *mac = NULL;
+		unsigned char mac_tmp[EVP_MAX_MD_SIZE];
+		mac_size=EVP_MD_CTX_size(s->read_hash);
+		OPENSSL_assert(mac_size <= EVP_MAX_MD_SIZE);
+
+		/* orig_len is the length of the record before any padding was
+		 * removed. This is public information, as is the MAC in use,
+		 * therefore we can safely process the record in a different
+		 * amount of time if it's too short to possibly contain a MAC.
+		 */
+		if (rr->orig_len < mac_size ||
+		    /* CBC records must have a padding length byte too. */
+		    (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE &&
+		     rr->orig_len < mac_size+1))
 			{
-#if 0 /* OK only for stream ciphers */
 			al=SSL_AD_DECODE_ERROR;
 			SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_LENGTH_TOO_SHORT);
 			goto f_err;
-#else
-			goto err;
-#endif
 			}
-		rr->length-=mac_size;
-		i=s->method->ssl3_enc->mac(s,md,0);
-		if (i < 0 || memcmp(md,&(rr->data[rr->length]),mac_size) != 0)
+
+		if (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE)
+			{
+			/* We update the length so that the TLS header bytes
+			 * can be constructed correctly but we need to extract
+			 * the MAC in constant time from within the record,
+			 * without leaking the contents of the padding bytes.
+			 * */
+			mac = mac_tmp;
+			ssl3_cbc_copy_mac(mac_tmp, rr, mac_size);
+			rr->length -= mac_size;
+			}
+		else
 			{
-			goto err;
+			/* In this case there's no padding, so |rec->orig_len|
+			 * equals |rec->length| and we checked that there's
+			 * enough bytes for |mac_size| above. */
+			rr->length -= mac_size;
+			mac = &rr->data[rr->length];
 			}
+
+		i=s->method->ssl3_enc->mac(s,md,0 /* not send */);
+		if (i < 0 || mac == NULL || CRYPTO_memcmp(md, mac, (size_t)mac_size) != 0)
+			enc_err = -1;
+		if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+mac_size)
+			enc_err = -1;
+		}
+
+	if (enc_err < 0)
+		{
+		/* decryption failed, silently discard message */
+		rr->length = 0;
+		s->packet_length = 0;
+		goto err;
 		}
 
 	/* r->length is now just compressed */
@@ -570,6 +587,9 @@ again:
 
 		p=s->packet;
 
+		if (s->msg_callback)
+			s->msg_callback(0, 0, SSL3_RT_HEADER, p, DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg);
+
 		/* Pull apart the header into the DTLS1_RECORD */
 		rr->type= *(p++);
 		ssl_major= *(p++);
@@ -695,7 +715,6 @@ again:
 		goto again;   /* get another record */
 		}
 
-	dtls1_clear_timeouts(s);  /* done waiting */
 	return(1);
 
 	}
@@ -829,6 +848,12 @@ start:
 			}
 		}
 
+	if (s->d1->listen && rr->type != SSL3_RT_HANDSHAKE)
+		{
+		rr->length = 0;
+		goto start;
+		}
+
 	/* we now have a packet which can be read and processed */
 
 	if (s->s3->change_cipher_spec /* set when we receive ChangeCipherSpec,
@@ -937,6 +962,19 @@ start:
 			dest = s->d1->alert_fragment;
 			dest_len = &s->d1->alert_fragment_len;
 			}
+#ifndef OPENSSL_NO_HEARTBEATS
+		else if (rr->type == TLS1_RT_HEARTBEAT)
+			{
+			dtls1_process_heartbeat(s);
+
+			/* Exit and notify application to read again */
+			rr->length = 0;
+			s->rwstate=SSL_READING;
+			BIO_clear_retry_flags(SSL_get_rbio(s));
+			BIO_set_retry_read(SSL_get_rbio(s));
+			return(-1);
+			}
+#endif
 		/* else it's a CCS message, or application data or wrong */
 		else if (rr->type != SSL3_RT_CHANGE_CIPHER_SPEC)
 			{
@@ -1020,6 +1058,7 @@ start:
 			!(s->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS) &&
 			!s->s3->renegotiate)
 			{
+			s->d1->handshake_read_seq++;
 			s->new_session = 1;
 			ssl3_renegotiate(s);
 			if (ssl3_renegotiate_check(s))
@@ -1234,6 +1273,9 @@ start:
 		 */
 		if (msg_hdr.type == SSL3_MT_FINISHED)
 			{
+			if (dtls1_check_timeout_num(s) < 0)
+				return -1;
+
 			dtls1_retransmit_buffered_messages(s);
 			rr->length = 0;
 			goto start;
@@ -1431,10 +1473,10 @@ int do_dtls1_write(SSL *s, int type, const unsigned char *buf, unsigned int len,
 	unsigned char *p,*pseq;
 	int i,mac_size,clear=0;
 	int prefix_len = 0;
+	int eivlen;
 	SSL3_RECORD *wr;
 	SSL3_BUFFER *wb;
 	SSL_SESSION *sess;
-	int bs;
 
 	/* first check if there is a SSL3_BUFFER still being written
 	 * out.  This will happen with non blocking IO */
@@ -1511,26 +1553,46 @@ int do_dtls1_write(SSL *s, int type, const unsigned char *buf, unsigned int len,
 
 	*(p++)=type&0xff;
 	wr->type=type;
-
-	*(p++)=(s->version>>8);
-	*(p++)=s->version&0xff;
+	/* Special case: for hello verify request, client version 1.0 and
+	 * we haven't decided which version to use yet send back using 
+	 * version 1.0 header: otherwise some clients will ignore it.
+	 */
+	if (s->method->version == DTLS_ANY_VERSION)
+		{
+		*(p++)=DTLS1_VERSION>>8;
+		*(p++)=DTLS1_VERSION&0xff;
+		}
+	else
+		{
+		*(p++)=s->version>>8;
+		*(p++)=s->version&0xff;
+		}
 
 	/* field where we are to write out packet epoch, seq num and len */
 	pseq=p; 
 	p+=10;
 
-	/* lets setup the record stuff. */
-
-	/* Make space for the explicit IV in case of CBC.
-	 * (this is a bit of a boundary violation, but what the heck).
-	 */
-	if ( s->enc_write_ctx && 
-		(EVP_CIPHER_mode( s->enc_write_ctx->cipher ) & EVP_CIPH_CBC_MODE))
-		bs = EVP_CIPHER_block_size(s->enc_write_ctx->cipher);
-	else
-		bs = 0;
+	/* Explicit IV length, block ciphers appropriate version flag */
+	if (s->enc_write_ctx)
+		{
+		int mode = EVP_CIPHER_CTX_mode(s->enc_write_ctx);
+		if (mode == EVP_CIPH_CBC_MODE)
+			{
+			eivlen = EVP_CIPHER_CTX_iv_length(s->enc_write_ctx);
+			if (eivlen <= 1)
+				eivlen = 0;
+			}
+		/* Need explicit part of IV for GCM mode */
+		else if (mode == EVP_CIPH_GCM_MODE)
+			eivlen = EVP_GCM_TLS_EXPLICIT_IV_LEN;
+		else
+			eivlen = 0;
+		}
+	else 
+		eivlen = 0;
 
-	wr->data=p + bs;  /* make room for IV in case of CBC */
+	/* lets setup the record stuff. */
+	wr->data=p + eivlen;  /* make room for IV in case of CBC */
 	wr->length=(int)len;
 	wr->input=(unsigned char *)buf;
 
@@ -1558,7 +1620,7 @@ int do_dtls1_write(SSL *s, int type, const unsigned char *buf, unsigned int len,
 
 	if (mac_size != 0)
 		{
-		if(s->method->ssl3_enc->mac(s,&(p[wr->length + bs]),1) < 0)
+		if(s->method->ssl3_enc->mac(s,&(p[wr->length + eivlen]),1) < 0)
 			goto err;
 		wr->length+=mac_size;
 		}
@@ -1567,15 +1629,8 @@ int do_dtls1_write(SSL *s, int type, const unsigned char *buf, unsigned int len,
 	wr->input=p;
 	wr->data=p;
 
-
-	/* ssl3_enc can only have an error on read */
-	if (bs)	/* bs != 0 in case of CBC */
-		{
-		RAND_pseudo_bytes(p,bs);
-		/* master IV and last CBC residue stand for
-		 * the rest of randomness */
-		wr->length += bs;
-		}
+	if (eivlen)
+		wr->length += eivlen;
 
 	s->method->ssl3_enc->enc(s,1);
 
@@ -1595,6 +1650,9 @@ int do_dtls1_write(SSL *s, int type, const unsigned char *buf, unsigned int len,
 	pseq+=6;
 	s2n(wr->length,pseq);
 
+	if (s->msg_callback)
+		s->msg_callback(1, 0, SSL3_RT_HEADER, pseq - DTLS1_RT_HEADER_LENGTH, DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg);
+
 	/* we should now have
 	 * wr->data pointing to the encrypted data, which is
 	 * wr->length long */
@@ -1857,10 +1915,3 @@ dtls1_reset_seq_numbers(SSL *s, int rw)
 
 	memset(seq, 0x00, seq_bytes);
 	}
-
-
-static void
-dtls1_clear_timeouts(SSL *s)
-	{
-	memset(&(s->d1->timeout), 0x00, sizeof(struct dtls1_timeout_st));
-	}