X-Git-Url: https://git.openssl.org/gitweb/?p=openssl.git;a=blobdiff_plain;f=ssl%2Fs3_pkt.c;h=c4bc4e787da079a0f05eceb2705c1f2bcb9cd956;hp=e3f6050a26acb2e547978df8c9ad51f99475549e;hb=0294b2b;hpb=0d0ed9187a48797b867e0ffc32b3ea9c5cc30639;ds=sidebyside

diff --git a/ssl/s3_pkt.c b/ssl/s3_pkt.c
index e3f6050a26..c4bc4e787d 100644
--- a/ssl/s3_pkt.c
+++ b/ssl/s3_pkt.c
@@ -115,6 +115,7 @@
 #include "ssl_locl.h"
 #include <openssl/evp.h>
 #include <openssl/buffer.h>
+#include <openssl/rand.h>
 
 static int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
 			 unsigned int len, int create_empty_fragment);
@@ -246,7 +247,8 @@ int ssl3_read_n(SSL *s, int n, int max, int extend)
 		if (i <= 0)
 			{
 			rb->left = left;
-			if (s->mode & SSL_MODE_RELEASE_BUFFERS)
+			if (s->mode & SSL_MODE_RELEASE_BUFFERS &&
+			    SSL_version(s) != DTLS1_VERSION && SSL_version(s) != DTLS1_BAD_VER)
 				if (len+left == 0)
 					ssl3_release_read_buffer(s);
 			return(i);
@@ -288,11 +290,8 @@ static int ssl3_get_record(SSL *s)
 	unsigned char *p;
 	unsigned char md[EVP_MAX_MD_SIZE];
 	short version;
-	int mac_size;
-	int clear=0;
+	unsigned mac_size, orig_len;
 	size_t extra;
-	int decryption_failed_or_bad_record_mac = 0;
-	unsigned char *mac = NULL;
 
 	rr= &(s->s3->rrec);
 	sess=s->session;
@@ -401,17 +400,15 @@ fprintf(stderr, "Record type=%d, Length=%d\n", rr->type, rr->length);
 	rr->data=rr->input;
 
 	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)
 		{
-		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;
+		al=SSL_AD_DECRYPTION_FAILED;
+		SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_BLOCK_CIPHER_PAD_IS_WRONG);
+		goto f_err;
 		}
 
 #ifdef TLS_DEBUG
@@ -421,53 +418,62 @@ printf("\n");
 #endif
 
 	/* r->length is now the compressed data plus mac */
-	if (	(sess == NULL) ||
-		(s->enc_read_ctx == NULL) ||
-		(EVP_MD_CTX_md(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 */
+		/* 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 >= 0);
+		OPENSSL_assert(mac_size <= EVP_MAX_MD_SIZE);
 
-		if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+extra+mac_size)
+		/* kludge: *_cbc_remove_padding passes padding length in rr->type */
+		orig_len = rr->length+((unsigned int)rr->type>>8);
+
+		/* 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 (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 &&
+		     orig_len < mac_size+1))
 			{
-#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);
+			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;
-#endif			
 			}
-		/* check the MAC for rr->input (it's in mac_size bytes at the tail) */
-		if (rr->length >= (unsigned int)mac_size)
+
+		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, orig_len);
 			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
-			}
-		i=s->method->ssl3_enc->mac(s,md,0);
-		if (i < 0 || mac == NULL || memcmp(md, mac, (size_t)mac_size) != 0)
-			{
-			decryption_failed_or_bad_record_mac = 1;
+			/* In this case there's no padding, so |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+extra+mac_size)
+			enc_err = -1;
 		}
 
-	if (decryption_failed_or_bad_record_mac)
+	if (enc_err < 0)
 		{
 		/* A separate 'decryption_failed' alert was introduced with TLS 1.0,
 		 * SSL 3.0 only has 'bad_record_mac'.  But unless a decryption
@@ -629,6 +635,7 @@ 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 eivlen;
 	long align=0;
 	SSL3_RECORD *wr;
 	SSL3_BUFFER *wb=&(s->s3->wbuf);
@@ -661,10 +668,14 @@ static int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
 	if (	(sess == NULL) ||
 		(s->enc_write_ctx == NULL) ||
 		(EVP_MD_CTX_md(s->write_hash) == NULL))
+		{
+#if 1
+		clear=s->enc_write_ctx?0:1;	/* must be AEAD cipher */
+#else
 		clear=1;
-
-	if (clear)
+#endif
 		mac_size=0;
+		}
 	else
 		{
 		mac_size=EVP_MD_CTX_size(s->write_hash);
@@ -733,14 +744,40 @@ static int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
 	wr->type=type;
 
 	*(p++)=(s->version>>8);
-	*(p++)=s->version&0xff;
+	/* Some servers hang if iniatial client hello is larger than 256
+	 * bytes and record version number > TLS 1.0
+	 */
+	if (s->state == SSL3_ST_CW_CLNT_HELLO_B
+				&& !s->renegotiate
+				&& TLS1_get_version(s) > TLS1_VERSION)
+		*(p++) = 0x1;
+	else
+		*(p++)=s->version&0xff;
 
 	/* field where we are to write out packet length */
 	plen=p; 
 	p+=2;
+	/* Explicit IV length, block ciphers and TLS version 1.1 or later */
+	if (s->enc_write_ctx && s->version >= TLS1_1_VERSION)
+		{
+		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;
 
 	/* lets setup the record stuff. */
-	wr->data=p;
+	wr->data=p + eivlen;
 	wr->length=(int)len;
 	wr->input=(unsigned char *)buf;
 
@@ -768,11 +805,19 @@ static int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
 
 	if (mac_size != 0)
 		{
-		if (s->method->ssl3_enc->mac(s,&(p[wr->length]),1) < 0)
+		if (s->method->ssl3_enc->mac(s,&(p[wr->length + eivlen]),1) < 0)
 			goto err;
 		wr->length+=mac_size;
-		wr->input=p;
-		wr->data=p;
+		}
+
+	wr->input=p;
+	wr->data=p;
+
+	if (eivlen)
+		{
+	/*	if (RAND_pseudo_bytes(p, eivlen) <= 0)
+			goto err; */
+		wr->length += eivlen;
 		}
 
 	/* ssl3_enc can only have an error on read */
@@ -846,7 +891,8 @@ int ssl3_write_pending(SSL *s, int type, const unsigned char *buf,
 			{
 			wb->left=0;
 			wb->offset+=i;
-			if (s->mode & SSL_MODE_RELEASE_BUFFERS)
+			if (s->mode & SSL_MODE_RELEASE_BUFFERS &&
+			    SSL_version(s) != DTLS1_VERSION && SSL_version(s) != DTLS1_BAD_VER)
 				ssl3_release_write_buffer(s);
 			s->rwstate=SSL_NOTHING;
 			return(s->s3->wpend_ret);
@@ -1040,6 +1086,19 @@ start:
 			dest = s->s3->alert_fragment;
 			dest_len = &s->s3->alert_fragment_len;
 			}
+#ifndef OPENSSL_NO_HEARTBEATS
+		else if (rr->type == TLS1_RT_HEARTBEAT)
+			{
+			tls1_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
 
 		if (dest_maxlen > 0)
 			{
@@ -1183,6 +1242,10 @@ start:
 				SSLerr(SSL_F_SSL3_READ_BYTES,SSL_R_NO_RENEGOTIATION);
 				goto f_err;
 				}
+#ifdef SSL_AD_MISSING_SRP_USERNAME
+			else if (alert_descr == SSL_AD_MISSING_SRP_USERNAME)
+				return(0);
+#endif
 			}
 		else if (alert_level == 2) /* fatal */
 			{
@@ -1261,6 +1324,7 @@ start:
 #else
 			s->state = s->server ? SSL_ST_ACCEPT : SSL_ST_CONNECT;
 #endif
+			s->renegotiate=1;
 			s->new_session=1;
 			}
 		i=s->handshake_func(s);
@@ -1294,8 +1358,10 @@ start:
 		{
 	default:
 #ifndef OPENSSL_NO_TLS
-		/* TLS just ignores unknown message types */
-		if (s->version == TLS1_VERSION)
+		/* TLS up to v1.1 just ignores unknown message types:
+		 * TLS v1.2 give an unexpected message alert.
+		 */
+		if (s->version >= TLS1_VERSION && s->version <= TLS1_1_VERSION)
 			{
 			rr->length = 0;
 			goto start;
@@ -1393,8 +1459,14 @@ int ssl3_do_change_cipher_spec(SSL *s)
 		slen=s->method->ssl3_enc->client_finished_label_len;
 		}
 
-	s->s3->tmp.peer_finish_md_len = s->method->ssl3_enc->final_finish_mac(s,
+	i = s->method->ssl3_enc->final_finish_mac(s,
 		sender,slen,s->s3->tmp.peer_finish_md);
+	if (i == 0)
+		{
+		SSLerr(SSL_F_SSL3_DO_CHANGE_CIPHER_SPEC, ERR_R_INTERNAL_ERROR);
+		return 0;
+		}
+	s->s3->tmp.peer_finish_md_len = i;
 
 	return(1);
 	}