From: Andy Polyakov <appro@openssl.org>
Date: Fri, 1 Feb 2013 14:31:50 +0000 (+0100)
Subject: ssl/*: remove SSL3_RECORD->orig_len to restore binary compatibility.
X-Git-Tag: OpenSSL_0_9_8za~84
X-Git-Url: https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff_plain;h=fb092ef4fca897344daf7189526f5f26be6487ce;hp=6351adecb4726476def5f5ad904a7d2e63480d53

ssl/*: remove SSL3_RECORD->orig_len to restore binary compatibility.

Kludge alert. This is arranged by passing padding length in unused
bits of SSL3_RECORD->type, so that orig_len can be reconstructed.
(cherry picked from commit 413cbfe68d83f9afc726b7234c49bd5ccddb97b4)
---

diff --git a/ssl/d1_pkt.c b/ssl/d1_pkt.c
index 3f0f983698..9db44c95f9 100644
--- a/ssl/d1_pkt.c
+++ b/ssl/d1_pkt.c
@@ -330,8 +330,8 @@ dtls1_process_record(SSL *s)
 	int i,al;
 	int enc_err;
 	SSL_SESSION *sess;
-    SSL3_RECORD *rr;
-	unsigned int mac_size;
+	SSL3_RECORD *rr;
+	unsigned int mac_size, orig_len;
 	unsigned char md[EVP_MAX_MD_SIZE];
 
 	rr= &(s->s3->rrec);
@@ -362,7 +362,7 @@ dtls1_process_record(SSL *s)
 
 	/* decrypt in place in 'rr->input' */
 	rr->data=rr->input;
-	rr->orig_len=rr->length;
+	orig_len=rr->length;
 
 	enc_err = s->method->ssl3_enc->enc(s,0);
 	/* enc_err is:
@@ -399,10 +399,10 @@ printf("\n");
 		 * 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 ||
+		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 &&
-		     rr->orig_len < mac_size+1))
+		     orig_len < mac_size+1))
 			{
 			al=SSL_AD_DECODE_ERROR;
 			SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_LENGTH_TOO_SHORT);
@@ -417,12 +417,12 @@ printf("\n");
 			 * without leaking the contents of the padding bytes.
 			 * */
 			mac = mac_tmp;
-			ssl3_cbc_copy_mac(mac_tmp, rr, mac_size);
+			ssl3_cbc_copy_mac(mac_tmp, rr, mac_size, orig_len);
 			rr->length -= mac_size;
 			}
 		else
 			{
-			/* In this case there's no padding, so |rec->orig_len|
+			/* 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;
diff --git a/ssl/s3_cbc.c b/ssl/s3_cbc.c
index ad695ae133..89d2933e25 100644
--- a/ssl/s3_cbc.c
+++ b/ssl/s3_cbc.c
@@ -116,7 +116,9 @@ int ssl3_cbc_remove_padding(const SSL* s,
 	good = constant_time_ge(rec->length, padding_length+overhead);
 	/* SSLv3 requires that the padding is minimal. */
 	good &= constant_time_ge(block_size, padding_length+1);
-	rec->length -= good & (padding_length+1);
+	padding_length = good & (padding_length+1);
+	rec->length -= padding_length;
+	rec->type |= padding_length<<8;	/* kludge: pass padding length */
 	return (int)((good & 1) | (~good & -1));
 }
 
@@ -202,7 +204,9 @@ int tls1_cbc_remove_padding(const SSL* s,
 	good <<= sizeof(good)*8-1;
 	good = DUPLICATE_MSB_TO_ALL(good);
 
-	rec->length -= good & (padding_length+1);
+	padding_length = good & (padding_length+1);
+	rec->length -= padding_length;
+	rec->type |= padding_length<<8;	/* kludge: pass padding length */
 
 	/* We can always safely skip the explicit IV. We check at the beginning
 	 * of this function that the record has at least enough space for the
@@ -217,7 +221,6 @@ int tls1_cbc_remove_padding(const SSL* s,
 		rec->data += block_size;
 		rec->input += block_size;
 		rec->length -= block_size;
-		rec->orig_len -= block_size;
 		}
 
 	return (int)((good & 1) | (~good & -1));
@@ -245,7 +248,7 @@ int tls1_cbc_remove_padding(const SSL* s,
  */
 void ssl3_cbc_copy_mac(unsigned char* out,
 		       const SSL3_RECORD *rec,
-		       unsigned md_size)
+		       unsigned md_size,unsigned orig_len)
 	{
 #if defined(CBC_MAC_ROTATE_IN_PLACE)
 	unsigned char rotated_mac_buf[EVP_MAX_MD_SIZE*2];
@@ -264,7 +267,7 @@ void ssl3_cbc_copy_mac(unsigned char* out,
 	unsigned div_spoiler;
 	unsigned rotate_offset;
 
-	OPENSSL_assert(rec->orig_len >= md_size);
+	OPENSSL_assert(orig_len >= md_size);
 	OPENSSL_assert(md_size <= EVP_MAX_MD_SIZE);
 
 #if defined(CBC_MAC_ROTATE_IN_PLACE)
@@ -272,8 +275,8 @@ void ssl3_cbc_copy_mac(unsigned char* out,
 #endif
 
 	/* This information is public so it's safe to branch based on it. */
-	if (rec->orig_len > md_size + 255 + 1)
-		scan_start = rec->orig_len - (md_size + 255 + 1);
+	if (orig_len > md_size + 255 + 1)
+		scan_start = orig_len - (md_size + 255 + 1);
 	/* div_spoiler contains a multiple of md_size that is used to cause the
 	 * modulo operation to be constant time. Without this, the time varies
 	 * based on the amount of padding when running on Intel chips at least.
@@ -286,9 +289,9 @@ void ssl3_cbc_copy_mac(unsigned char* out,
 	rotate_offset = (div_spoiler + mac_start - scan_start) % md_size;
 
 	memset(rotated_mac, 0, md_size);
-	for (i = scan_start; i < rec->orig_len;)
+	for (i = scan_start; i < orig_len;)
 		{
-		for (j = 0; j < md_size && i < rec->orig_len; i++, j++)
+		for (j = 0; j < md_size && i < orig_len; i++, j++)
 			{
 			unsigned char mac_started = constant_time_ge(i, mac_start);
 			unsigned char mac_ended = constant_time_ge(i, mac_end);
diff --git a/ssl/s3_enc.c b/ssl/s3_enc.c
index 170953ca8d..409a15b8a7 100644
--- a/ssl/s3_enc.c
+++ b/ssl/s3_enc.c
@@ -587,7 +587,7 @@ int ssl3_mac(SSL *ssl, unsigned char *md, int send)
 	EVP_MD_CTX md_ctx;
 	const EVP_MD *hash;
 	unsigned char *p,rec_char;
-	size_t md_size;
+	size_t md_size, orig_len;
 	int npad;
 
 	if (send)
@@ -608,6 +608,10 @@ int ssl3_mac(SSL *ssl, unsigned char *md, int send)
 	md_size=EVP_MD_size(hash);
 	npad=(48/md_size)*md_size;
 
+	/* kludge: ssl3_cbc_remove_padding passes padding length in rec->type */
+	orig_len = rec->length+md_size+((unsigned int)rec->type>>8);
+	rec->type &= 0xff;
+
 	if (!send &&
 	    EVP_CIPHER_CTX_mode(ssl->enc_read_ctx) == EVP_CIPH_CBC_MODE &&
 	    ssl3_cbc_record_digest_supported(hash))
@@ -639,7 +643,7 @@ int ssl3_mac(SSL *ssl, unsigned char *md, int send)
 			hash,
 			md, &md_size,
 			header, rec->input,
-			rec->length + md_size, rec->orig_len,
+			rec->length + md_size, orig_len,
 			mac_sec, md_size,
 			1 /* is SSLv3 */);
 		}
diff --git a/ssl/s3_pkt.c b/ssl/s3_pkt.c
index 6d0a2ee0ca..707738be94 100644
--- a/ssl/s3_pkt.c
+++ b/ssl/s3_pkt.c
@@ -246,7 +246,7 @@ static int ssl3_get_record(SSL *s)
 	unsigned char *p;
 	unsigned char md[EVP_MAX_MD_SIZE];
 	short version;
-	unsigned mac_size;
+	unsigned mac_size, orig_len;
 	size_t extra;
 
 	rr= &(s->s3->rrec);
@@ -351,7 +351,7 @@ again:
 
 	/* decrypt in place in 'rr->input' */
 	rr->data=rr->input;
-	rr->orig_len=rr->length;
+	orig_len=rr->length;
 
 	enc_err = s->method->ssl3_enc->enc(s,0);
 	/* enc_err is:
@@ -387,10 +387,10 @@ printf("\n");
 		 * 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 ||
+		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 &&
-		     rr->orig_len < mac_size+1))
+		     orig_len < mac_size+1))
 			{
 			al=SSL_AD_DECODE_ERROR;
 			SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_LENGTH_TOO_SHORT);
@@ -405,12 +405,12 @@ printf("\n");
 			 * without leaking the contents of the padding bytes.
 			 * */
 			mac = mac_tmp;
-			ssl3_cbc_copy_mac(mac_tmp, rr, mac_size);
+			ssl3_cbc_copy_mac(mac_tmp, rr, mac_size, orig_len);
 			rr->length -= mac_size;
 			}
 		else
 			{
-			/* In this case there's no padding, so |rec->orig_len|
+			/* 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;
diff --git a/ssl/ssl3.h b/ssl/ssl3.h
index 7709effe3e..b9a85effa0 100644
--- a/ssl/ssl3.h
+++ b/ssl/ssl3.h
@@ -304,10 +304,6 @@ typedef struct ssl3_record_st
 /*r */	unsigned char *comp;    /* only used with decompression - malloc()ed */
 /*r */  unsigned long epoch;    /* epoch number, needed by DTLS1 */
 /*r */  PQ_64BIT seq_num;       /* sequence number, needed by DTLS1 */
-/*rw*/	unsigned int orig_len;  /* How many bytes were available before padding
-				   was removed? This is used to implement the
-				   MAC check in constant time for CBC records.
-				 */
 	} SSL3_RECORD;
 
 typedef struct ssl3_buffer_st
diff --git a/ssl/ssl_locl.h b/ssl/ssl_locl.h
index 57e92323fc..d4b642c5aa 100644
--- a/ssl/ssl_locl.h
+++ b/ssl/ssl_locl.h
@@ -1015,7 +1015,7 @@ int ssl_parse_clienthello_renegotiate_ext(SSL *s, unsigned char *d, int len,
 /* s3_cbc.c */
 void ssl3_cbc_copy_mac(unsigned char* out,
 		       const SSL3_RECORD *rec,
-		       unsigned md_size);
+		       unsigned md_size,unsigned orig_len);
 int ssl3_cbc_remove_padding(const SSL* s,
 			    SSL3_RECORD *rec,
 			    unsigned block_size,
diff --git a/ssl/t1_enc.c b/ssl/t1_enc.c
index e75a66ba9d..3dd36b8142 100644
--- a/ssl/t1_enc.c
+++ b/ssl/t1_enc.c
@@ -689,7 +689,7 @@ int tls1_mac(SSL *ssl, unsigned char *md, int send)
 	SSL3_RECORD *rec;
 	unsigned char *mac_sec,*seq;
 	const EVP_MD *hash;
-	size_t md_size;
+	size_t md_size, orig_len;
 	int i;
 	HMAC_CTX hmac;
 	unsigned char header[13];
@@ -727,6 +727,10 @@ int tls1_mac(SSL *ssl, unsigned char *md, int send)
 	else
 		memcpy(header, seq, 8);
 
+	/* kludge: tls1_cbc_remove_padding passes padding length in rec->type */
+	orig_len = rec->length+md_size+((unsigned int)rec->type>>8);
+	rec->type &= 0xff;
+
 	header[8]=rec->type;
 	header[9]=(unsigned char)(ssl->version>>8);
 	header[10]=(unsigned char)(ssl->version);
@@ -745,7 +749,7 @@ int tls1_mac(SSL *ssl, unsigned char *md, int send)
 		        hash,
 			md, &md_size,
 			header, rec->input,
-			rec->length + md_size, rec->orig_len,
+			rec->length + md_size, orig_len,
 			ssl->s3->read_mac_secret,
 			EVP_MD_size(ssl->read_hash),
 			0 /* not SSLv3 */);