Delete bundled copy of OpenSSL and replace with README.

openssl/ssl/s3_cbc.c

Index: openssl/ssl/s3_cbc.c
diff --git a/openssl/ssl/s3_cbc.c b/openssl/ssl/s3_cbc.c
deleted file mode 100644
index 02edf3f9189e3888df67e7074b0b88c3d45fc576..0000000000000000000000000000000000000000
--- a/openssl/ssl/s3_cbc.c
+++ /dev/null
@@ -1,790 +0,0 @@
-/* ssl/s3_cbc.c */
-/* ====================================================================
- * Copyright (c) 2012 The OpenSSL Project.  All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in
- *    the documentation and/or other materials provided with the
- *    distribution.
- *
- * 3. All advertising materials mentioning features or use of this
- *    software must display the following acknowledgment:
- *    "This product includes software developed by the OpenSSL Project
- *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
- *
- * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
- *    endorse or promote products derived from this software without
- *    prior written permission. For written permission, please contact
- *    openssl-core@openssl.org.
- *
- * 5. Products derived from this software may not be called "OpenSSL"
- *    nor may "OpenSSL" appear in their names without prior written
- *    permission of the OpenSSL Project.
- *
- * 6. Redistributions of any form whatsoever must retain the following
- *    acknowledgment:
- *    "This product includes software developed by the OpenSSL Project
- *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
- *
- * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
- * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
- * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
- * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
- * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
- * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
- * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
- * OF THE POSSIBILITY OF SUCH DAMAGE.
- * ====================================================================
- *
- * This product includes cryptographic software written by Eric Young
- * (eay@cryptsoft.com).  This product includes software written by Tim
- * Hudson (tjh@cryptsoft.com).
- *
- */
-
-#include "ssl_locl.h"
-
-#include <openssl/md5.h>
-#include <openssl/sha.h>
-
-/* MAX_HASH_BIT_COUNT_BYTES is the maximum number of bytes in the hash's length
- * field. (SHA-384/512 have 128-bit length.) */
-#define MAX_HASH_BIT_COUNT_BYTES 16
-
-/* MAX_HASH_BLOCK_SIZE is the maximum hash block size that we'll support.
- * Currently SHA-384/512 has a 128-byte block size and that's the largest
- * supported by TLS.) */
-#define MAX_HASH_BLOCK_SIZE 128
-
-/* Some utility functions are needed:
- *
- * These macros return the given value with the MSB copied to all the other
- * bits. They use the fact that arithmetic shift shifts-in the sign bit.
- * However, this is not ensured by the C standard so you may need to replace
- * them with something else on odd CPUs. */
-#define DUPLICATE_MSB_TO_ALL(x) ( (unsigned)( (int)(x) >> (sizeof(int)*8-1) ) )
-#define DUPLICATE_MSB_TO_ALL_8(x) ((unsigned char)(DUPLICATE_MSB_TO_ALL(x)))
-
-/* constant_time_lt returns 0xff if a<b and 0x00 otherwise. */
-static unsigned constant_time_lt(unsigned a, unsigned b)
-	{
-	a -= b;
-	return DUPLICATE_MSB_TO_ALL(a);
-	}
-
-/* constant_time_ge returns 0xff if a>=b and 0x00 otherwise. */
-static unsigned constant_time_ge(unsigned a, unsigned b)
-	{
-	a -= b;
-	return DUPLICATE_MSB_TO_ALL(~a);
-	}
-
-/* constant_time_eq_8 returns 0xff if a==b and 0x00 otherwise. */
-static unsigned char constant_time_eq_8(unsigned a, unsigned b)
-	{
-	unsigned c = a ^ b;
-	c--;
-	return DUPLICATE_MSB_TO_ALL_8(c);
-	}
-
-/* ssl3_cbc_remove_padding removes padding from the decrypted, SSLv3, CBC
- * record in |rec| by updating |rec->length| in constant time.
- *
- * block_size: the block size of the cipher used to encrypt the record.
- * returns:
- *   0: (in non-constant time) if the record is publicly invalid.
- *   1: if the padding was valid
- *  -1: otherwise. */
-int ssl3_cbc_remove_padding(const SSL* s,
-			    SSL3_RECORD *rec,
-			    unsigned block_size,
-			    unsigned mac_size)
-	{
-	unsigned padding_length, good;
-	const unsigned overhead = 1 /* padding length byte */ + mac_size;
-
-	/* These lengths are all public so we can test them in non-constant
-	 * time. */
-	if (overhead > rec->length)
-		return 0;
-
-	padding_length = rec->data[rec->length-1];
-	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);
-	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));
-}
-
-/* tls1_cbc_remove_padding removes the CBC padding from the decrypted, TLS, CBC
- * record in |rec| in constant time and returns 1 if the padding is valid and
- * -1 otherwise. It also removes any explicit IV from the start of the record
- * without leaking any timing about whether there was enough space after the
- * padding was removed.
- *
- * block_size: the block size of the cipher used to encrypt the record.
- * returns:
- *   0: (in non-constant time) if the record is publicly invalid.
- *   1: if the padding was valid
- *  -1: otherwise. */
-int tls1_cbc_remove_padding(const SSL* s,
-			    SSL3_RECORD *rec,
-			    unsigned block_size,
-			    unsigned mac_size)
-	{
-	unsigned padding_length, good, to_check, i;
-	const unsigned overhead = 1 /* padding length byte */ + mac_size;
-	/* Check if version requires explicit IV */
-	if (s->version >= TLS1_1_VERSION || s->version == DTLS1_VERSION)
-		{
-		/* These lengths are all public so we can test them in
-		 * non-constant time.
-		 */
-		if (overhead + block_size > rec->length)
-			return 0;
-		/* We can now safely skip explicit IV */
-		rec->data += block_size;
-		rec->input += block_size;
-		rec->length -= block_size;
-		}
-	else if (overhead > rec->length)
-		return 0;
-
-	padding_length = rec->data[rec->length-1];
-
-	/* NB: if compression is in operation the first packet may not be of
-	 * even length so the padding bug check cannot be performed. This bug
-	 * workaround has been around since SSLeay so hopefully it is either
-	 * fixed now or no buggy implementation supports compression [steve]
-	 */
-	if ( (s->options&SSL_OP_TLS_BLOCK_PADDING_BUG) && !s->expand)
-		{
-		/* First packet is even in size, so check */
-		if ((memcmp(s->s3->read_sequence, "\0\0\0\0\0\0\0\0",8) == 0) &&
-		    !(padding_length & 1))
-			{
-			s->s3->flags|=TLS1_FLAGS_TLS_PADDING_BUG;
-			}
-		if ((s->s3->flags & TLS1_FLAGS_TLS_PADDING_BUG) &&
-		    padding_length > 0)
-			{
-			padding_length--;
-			}
-		}
-
-	if (EVP_CIPHER_flags(s->enc_read_ctx->cipher)&EVP_CIPH_FLAG_AEAD_CIPHER)
-		{
-		/* padding is already verified */
-		rec->length -= padding_length + 1;
-		return 1;
-		}
-
-	good = constant_time_ge(rec->length, overhead+padding_length);
-	/* The padding consists of a length byte at the end of the record and
-	 * then that many bytes of padding, all with the same value as the
-	 * length byte. Thus, with the length byte included, there are i+1
-	 * bytes of padding.
-	 *
-	 * We can't check just |padding_length+1| bytes because that leaks
-	 * decrypted information. Therefore we always have to check the maximum
-	 * amount of padding possible. (Again, the length of the record is
-	 * public information so we can use it.) */
-	to_check = 255; /* maximum amount of padding. */
-	if (to_check > rec->length-1)
-		to_check = rec->length-1;
-
-	for (i = 0; i < to_check; i++)
-		{
-		unsigned char mask = constant_time_ge(padding_length, i);
-		unsigned char b = rec->data[rec->length-1-i];
-		/* The final |padding_length+1| bytes should all have the value
-		 * |padding_length|. Therefore the XOR should be zero. */
-		good &= ~(mask&(padding_length ^ b));
-		}
-
-	/* If any of the final |padding_length+1| bytes had the wrong value,
-	 * one or more of the lower eight bits of |good| will be cleared. We
-	 * AND the bottom 8 bits together and duplicate the result to all the
-	 * bits. */
-	good &= good >> 4;
-	good &= good >> 2;
-	good &= good >> 1;
-	good <<= sizeof(good)*8-1;
-	good = DUPLICATE_MSB_TO_ALL(good);
-
-	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));
-	}
-
-/* ssl3_cbc_copy_mac copies |md_size| bytes from the end of |rec| to |out| in
- * constant time (independent of the concrete value of rec->length, which may
- * vary within a 256-byte window).
- *
- * ssl3_cbc_remove_padding or tls1_cbc_remove_padding must be called prior to
- * this function.
- *
- * On entry:
- *   rec->orig_len >= md_size
- *   md_size <= EVP_MAX_MD_SIZE
- *
- * If CBC_MAC_ROTATE_IN_PLACE is defined then the rotation is performed with
- * variable accesses in a 64-byte-aligned buffer. Assuming that this fits into
- * a single or pair of cache-lines, then the variable memory accesses don't
- * actually affect the timing. CPUs with smaller cache-lines [if any] are
- * not multi-core and are not considered vulnerable to cache-timing attacks.
- */
-#define CBC_MAC_ROTATE_IN_PLACE
-
-void ssl3_cbc_copy_mac(unsigned char* out,
-		       const SSL3_RECORD *rec,
-		       unsigned md_size,unsigned orig_len)
-	{
-#if defined(CBC_MAC_ROTATE_IN_PLACE)
-	unsigned char rotated_mac_buf[64+EVP_MAX_MD_SIZE];
-	unsigned char *rotated_mac;
-#else
-	unsigned char rotated_mac[EVP_MAX_MD_SIZE];
-#endif
-
-	/* mac_end is the index of |rec->data| just after the end of the MAC. */
-	unsigned mac_end = rec->length;
-	unsigned mac_start = mac_end - md_size;
-	/* scan_start contains the number of bytes that we can ignore because
-	 * the MAC's position can only vary by 255 bytes. */
-	unsigned scan_start = 0;
-	unsigned i, j;
-	unsigned div_spoiler;
-	unsigned rotate_offset;
-
-	OPENSSL_assert(orig_len >= md_size);
-	OPENSSL_assert(md_size <= EVP_MAX_MD_SIZE);
-
-#if defined(CBC_MAC_ROTATE_IN_PLACE)
-	rotated_mac = rotated_mac_buf + ((0-(size_t)rotated_mac_buf)&63);
-#endif
-
-	/* This information is public so it's safe to branch based on it. */
-	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.
-	 *
-	 * The aim of right-shifting md_size is so that the compiler doesn't
-	 * figure out that it can remove div_spoiler as that would require it
-	 * to prove that md_size is always even, which I hope is beyond it. */
-	div_spoiler = md_size >> 1;
-	div_spoiler <<= (sizeof(div_spoiler)-1)*8;
-	rotate_offset = (div_spoiler + mac_start - scan_start) % md_size;
-
-	memset(rotated_mac, 0, md_size);
-	for (i = scan_start, j = 0; i < orig_len; i++)
-		{
-		unsigned char mac_started = constant_time_ge(i, mac_start);
-		unsigned char mac_ended = constant_time_ge(i, mac_end);
-		unsigned char b = rec->data[i];
-		rotated_mac[j++] |= b & mac_started & ~mac_ended;
-		j &= constant_time_lt(j,md_size);
-		}
-
-	/* Now rotate the MAC */
-#if defined(CBC_MAC_ROTATE_IN_PLACE)
-	j = 0;
-	for (i = 0; i < md_size; i++)
-		{
-		/* in case cache-line is 32 bytes, touch second line */
-		((volatile unsigned char *)rotated_mac)[rotate_offset^32];
-		out[j++] = rotated_mac[rotate_offset++];
-		rotate_offset &= constant_time_lt(rotate_offset,md_size);
-		}
-#else
-	memset(out, 0, md_size);
-	rotate_offset = md_size - rotate_offset;
-	rotate_offset &= constant_time_lt(rotate_offset,md_size);
-	for (i = 0; i < md_size; i++)
-		{
-		for (j = 0; j < md_size; j++)
-			out[j] |= rotated_mac[i] & constant_time_eq_8(j, rotate_offset);
-		rotate_offset++;
-		rotate_offset &= constant_time_lt(rotate_offset,md_size);
-		}
-#endif
-	}
-
-/* u32toLE serialises an unsigned, 32-bit number (n) as four bytes at (p) in
- * little-endian order. The value of p is advanced by four. */
-#define u32toLE(n, p) \
-	(*((p)++)=(unsigned char)(n), \
-	 *((p)++)=(unsigned char)(n>>8), \
-	 *((p)++)=(unsigned char)(n>>16), \
-	 *((p)++)=(unsigned char)(n>>24))
-
-/* These functions serialize the state of a hash and thus perform the standard
- * "final" operation without adding the padding and length that such a function
- * typically does. */
-static void tls1_md5_final_raw(void* ctx, unsigned char *md_out)
-	{
-	MD5_CTX *md5 = ctx;
-	u32toLE(md5->A, md_out);
-	u32toLE(md5->B, md_out);
-	u32toLE(md5->C, md_out);
-	u32toLE(md5->D, md_out);
-	}
-
-static void tls1_sha1_final_raw(void* ctx, unsigned char *md_out)
-	{
-	SHA_CTX *sha1 = ctx;
-	l2n(sha1->h0, md_out);
-	l2n(sha1->h1, md_out);
-	l2n(sha1->h2, md_out);
-	l2n(sha1->h3, md_out);
-	l2n(sha1->h4, md_out);
-	}
-#define LARGEST_DIGEST_CTX SHA_CTX
-
-#ifndef OPENSSL_NO_SHA256
-static void tls1_sha256_final_raw(void* ctx, unsigned char *md_out)
-	{
-	SHA256_CTX *sha256 = ctx;
-	unsigned i;
-
-	for (i = 0; i < 8; i++)
-		{
-		l2n(sha256->h[i], md_out);
-		}
-	}
-#undef  LARGEST_DIGEST_CTX
-#define LARGEST_DIGEST_CTX SHA256_CTX
-#endif
-
-#ifndef OPENSSL_NO_SHA512
-static void tls1_sha512_final_raw(void* ctx, unsigned char *md_out)
-	{
-	SHA512_CTX *sha512 = ctx;
-	unsigned i;
-
-	for (i = 0; i < 8; i++)
-		{
-		l2n8(sha512->h[i], md_out);
-		}
-	}
-#undef  LARGEST_DIGEST_CTX
-#define LARGEST_DIGEST_CTX SHA512_CTX
-#endif
-
-/* ssl3_cbc_record_digest_supported returns 1 iff |ctx| uses a hash function
- * which ssl3_cbc_digest_record supports. */
-char ssl3_cbc_record_digest_supported(const EVP_MD_CTX *ctx)
-	{
-#ifdef OPENSSL_FIPS
-	if (FIPS_mode())
-		return 0;
-#endif
-	switch (EVP_MD_CTX_type(ctx))
-		{
-		case NID_md5:
-		case NID_sha1:
-#ifndef OPENSSL_NO_SHA256
-		case NID_sha224:
-		case NID_sha256:
-#endif
-#ifndef OPENSSL_NO_SHA512
-		case NID_sha384:
-		case NID_sha512:
-#endif
-			return 1;
-		default:
-			return 0;
-		}
-	}
-
-/* ssl3_cbc_digest_record computes the MAC of a decrypted, padded SSLv3/TLS
- * record.
- *
- *   ctx: the EVP_MD_CTX from which we take the hash function.
- *     ssl3_cbc_record_digest_supported must return true for this EVP_MD_CTX.
- *   md_out: the digest output. At most EVP_MAX_MD_SIZE bytes will be written.
- *   md_out_size: if non-NULL, the number of output bytes is written here.
- *   header: the 13-byte, TLS record header.
- *   data: the record data itself, less any preceeding explicit IV.
- *   data_plus_mac_size: the secret, reported length of the data and MAC
- *     once the padding has been removed.
- *   data_plus_mac_plus_padding_size: the public length of the whole
- *     record, including padding.
- *   is_sslv3: non-zero if we are to use SSLv3. Otherwise, TLS.
- *
- * On entry: by virtue of having been through one of the remove_padding
- * functions, above, we know that data_plus_mac_size is large enough to contain
- * a padding byte and MAC. (If the padding was invalid, it might contain the
- * padding too. ) */
-void ssl3_cbc_digest_record(
-	const EVP_MD_CTX *ctx,
-	unsigned char* md_out,
-	size_t* md_out_size,
-	const unsigned char header[13],
-	const unsigned char *data,
-	size_t data_plus_mac_size,
-	size_t data_plus_mac_plus_padding_size,
-	const unsigned char *mac_secret,
-	unsigned mac_secret_length,
-	char is_sslv3)
-	{
-	union {	double align;
-		unsigned char c[sizeof(LARGEST_DIGEST_CTX)]; } md_state;
-	void (*md_final_raw)(void *ctx, unsigned char *md_out);
-	void (*md_transform)(void *ctx, const unsigned char *block);
-	unsigned md_size, md_block_size = 64;
-	unsigned sslv3_pad_length = 40, header_length, variance_blocks,
-		 len, max_mac_bytes, num_blocks,
-		 num_starting_blocks, k, mac_end_offset, c, index_a, index_b;
-	unsigned int bits;	/* at most 18 bits */
-	unsigned char length_bytes[MAX_HASH_BIT_COUNT_BYTES];
-	/* hmac_pad is the masked HMAC key. */
-	unsigned char hmac_pad[MAX_HASH_BLOCK_SIZE];
-	unsigned char first_block[MAX_HASH_BLOCK_SIZE];
-	unsigned char mac_out[EVP_MAX_MD_SIZE];
-	unsigned i, j, md_out_size_u;
-	EVP_MD_CTX md_ctx;
-	/* mdLengthSize is the number of bytes in the length field that terminates
-	* the hash. */
-	unsigned md_length_size = 8;
-	char length_is_big_endian = 1;
-
-	/* This is a, hopefully redundant, check that allows us to forget about
-	 * many possible overflows later in this function. */
-	OPENSSL_assert(data_plus_mac_plus_padding_size < 1024*1024);
-
-	switch (EVP_MD_CTX_type(ctx))
-		{
-		case NID_md5:
-			MD5_Init((MD5_CTX*)md_state.c);
-			md_final_raw = tls1_md5_final_raw;
-			md_transform = (void(*)(void *ctx, const unsigned char *block)) MD5_Transform;
-			md_size = 16;
-			sslv3_pad_length = 48;
-			length_is_big_endian = 0;
-			break;
-		case NID_sha1:
-			SHA1_Init((SHA_CTX*)md_state.c);
-			md_final_raw = tls1_sha1_final_raw;
-			md_transform = (void(*)(void *ctx, const unsigned char *block)) SHA1_Transform;
-			md_size = 20;
-			break;
-#ifndef OPENSSL_NO_SHA256
-		case NID_sha224:
-			SHA224_Init((SHA256_CTX*)md_state.c);
-			md_final_raw = tls1_sha256_final_raw;
-			md_transform = (void(*)(void *ctx, const unsigned char *block)) SHA256_Transform;
-			md_size = 224/8;
-			break;
-		case NID_sha256:
-			SHA256_Init((SHA256_CTX*)md_state.c);
-			md_final_raw = tls1_sha256_final_raw;
-			md_transform = (void(*)(void *ctx, const unsigned char *block)) SHA256_Transform;
-			md_size = 32;
-			break;
-#endif
-#ifndef OPENSSL_NO_SHA512
-		case NID_sha384:
-			SHA384_Init((SHA512_CTX*)md_state.c);
-			md_final_raw = tls1_sha512_final_raw;
-			md_transform = (void(*)(void *ctx, const unsigned char *block)) SHA512_Transform;
-			md_size = 384/8;
-			md_block_size = 128;
-			md_length_size = 16;
-			break;
-		case NID_sha512:
-			SHA512_Init((SHA512_CTX*)md_state.c);
-			md_final_raw = tls1_sha512_final_raw;
-			md_transform = (void(*)(void *ctx, const unsigned char *block)) SHA512_Transform;
-			md_size = 64;
-			md_block_size = 128;
-			md_length_size = 16;
-			break;
-#endif
-		default:
-			/* ssl3_cbc_record_digest_supported should have been
-			 * called first to check that the hash function is
-			 * supported. */
-			OPENSSL_assert(0);
-			if (md_out_size)
-				*md_out_size = -1;
-			return;
-		}
-
-	OPENSSL_assert(md_length_size <= MAX_HASH_BIT_COUNT_BYTES);
-	OPENSSL_assert(md_block_size <= MAX_HASH_BLOCK_SIZE);
-	OPENSSL_assert(md_size <= EVP_MAX_MD_SIZE);
-
-	header_length = 13;
-	if (is_sslv3)
-		{
-		header_length =
-			mac_secret_length +
-			sslv3_pad_length +
-			8 /* sequence number */ +
-			1 /* record type */ +
-			2 /* record length */;
-		}
-
-	/* variance_blocks is the number of blocks of the hash that we have to
-	 * calculate in constant time because they could be altered by the
-	 * padding value.
-	 *
-	 * In SSLv3, the padding must be minimal so the end of the plaintext
-	 * varies by, at most, 15+20 = 35 bytes. (We conservatively assume that
-	 * the MAC size varies from 0..20 bytes.) In case the 9 bytes of hash
-	 * termination (0x80 + 64-bit length) don't fit in the final block, we
-	 * say that the final two blocks can vary based on the padding.
-	 *
-	 * TLSv1 has MACs up to 48 bytes long (SHA-384) and the padding is not
-	 * required to be minimal. Therefore we say that the final six blocks
-	 * can vary based on the padding.
-	 *
-	 * Later in the function, if the message is short and there obviously
-	 * cannot be this many blocks then variance_blocks can be reduced. */
-	variance_blocks = is_sslv3 ? 2 : 6;
-	/* From now on we're dealing with the MAC, which conceptually has 13
-	 * bytes of `header' before the start of the data (TLS) or 71/75 bytes
-	 * (SSLv3) */
-	len = data_plus_mac_plus_padding_size + header_length;
-	/* max_mac_bytes contains the maximum bytes of bytes in the MAC, including
-	* |header|, assuming that there's no padding. */
-	max_mac_bytes = len - md_size - 1;
-	/* num_blocks is the maximum number of hash blocks. */
-	num_blocks = (max_mac_bytes + 1 + md_length_size + md_block_size - 1) / md_block_size;
-	/* In order to calculate the MAC in constant time we have to handle
-	 * the final blocks specially because the padding value could cause the
-	 * end to appear somewhere in the final |variance_blocks| blocks and we
-	 * can't leak where. However, |num_starting_blocks| worth of data can
-	 * be hashed right away because no padding value can affect whether
-	 * they are plaintext. */
-	num_starting_blocks = 0;
-	/* k is the starting byte offset into the conceptual header||data where
-	 * we start processing. */
-	k = 0;
-	/* mac_end_offset is the index just past the end of the data to be
-	 * MACed. */
-	mac_end_offset = data_plus_mac_size + header_length - md_size;
-	/* c is the index of the 0x80 byte in the final hash block that
-	 * contains application data. */
-	c = mac_end_offset % md_block_size;
-	/* index_a is the hash block number that contains the 0x80 terminating
-	 * value. */
-	index_a = mac_end_offset / md_block_size;
-	/* index_b is the hash block number that contains the 64-bit hash
-	 * length, in bits. */
-	index_b = (mac_end_offset + md_length_size) / md_block_size;
-	/* bits is the hash-length in bits. It includes the additional hash
-	 * block for the masked HMAC key, or whole of |header| in the case of
-	 * SSLv3. */
-
-	/* For SSLv3, if we're going to have any starting blocks then we need
-	 * at least two because the header is larger than a single block. */
-	if (num_blocks > variance_blocks + (is_sslv3 ? 1 : 0))
-		{
-		num_starting_blocks = num_blocks - variance_blocks;
-		k = md_block_size*num_starting_blocks;
-		}
-
-	bits = 8*mac_end_offset;
-	if (!is_sslv3)
-		{
-		/* Compute the initial HMAC block. For SSLv3, the padding and
-		 * secret bytes are included in |header| because they take more
-		 * than a single block. */
-		bits += 8*md_block_size;
-		memset(hmac_pad, 0, md_block_size);
-		OPENSSL_assert(mac_secret_length <= sizeof(hmac_pad));
-		memcpy(hmac_pad, mac_secret, mac_secret_length);
-		for (i = 0; i < md_block_size; i++)
-			hmac_pad[i] ^= 0x36;
-
-		md_transform(md_state.c, hmac_pad);
-		}
-
-	if (length_is_big_endian)
-		{
-		memset(length_bytes,0,md_length_size-4);
-		length_bytes[md_length_size-4] = (unsigned char)(bits>>24);
-		length_bytes[md_length_size-3] = (unsigned char)(bits>>16);
-		length_bytes[md_length_size-2] = (unsigned char)(bits>>8);
-		length_bytes[md_length_size-1] = (unsigned char)bits;
-		}
-	else
-		{
-		memset(length_bytes,0,md_length_size);
-		length_bytes[md_length_size-5] = (unsigned char)(bits>>24);
-		length_bytes[md_length_size-6] = (unsigned char)(bits>>16);
-		length_bytes[md_length_size-7] = (unsigned char)(bits>>8);
-		length_bytes[md_length_size-8] = (unsigned char)bits;
-		}
-
-	if (k > 0)
-		{
-		if (is_sslv3)
-			{
-			/* The SSLv3 header is larger than a single block.
-			 * overhang is the number of bytes beyond a single
-			 * block that the header consumes: either 7 bytes
-			 * (SHA1) or 11 bytes (MD5). */
-			unsigned overhang = header_length-md_block_size;
-			md_transform(md_state.c, header);
-			memcpy(first_block, header + md_block_size, overhang);
-			memcpy(first_block + overhang, data, md_block_size-overhang);
-			md_transform(md_state.c, first_block);
-			for (i = 1; i < k/md_block_size - 1; i++)
-				md_transform(md_state.c, data + md_block_size*i - overhang);
-			}
-		else
-			{
-			/* k is a multiple of md_block_size. */
-			memcpy(first_block, header, 13);
-			memcpy(first_block+13, data, md_block_size-13);
-			md_transform(md_state.c, first_block);
-			for (i = 1; i < k/md_block_size; i++)
-				md_transform(md_state.c, data + md_block_size*i - 13);
-			}
-		}
-
-	memset(mac_out, 0, sizeof(mac_out));
-
-	/* We now process the final hash blocks. For each block, we construct
-	 * it in constant time. If the |i==index_a| then we'll include the 0x80
-	 * bytes and zero pad etc. For each block we selectively copy it, in
-	 * constant time, to |mac_out|. */
-	for (i = num_starting_blocks; i <= num_starting_blocks+variance_blocks; i++)
-		{
-		unsigned char block[MAX_HASH_BLOCK_SIZE];
-		unsigned char is_block_a = constant_time_eq_8(i, index_a);
-		unsigned char is_block_b = constant_time_eq_8(i, index_b);
-		for (j = 0; j < md_block_size; j++)
-			{
-			unsigned char b = 0, is_past_c, is_past_cp1;
-			if (k < header_length)
-				b = header[k];
-			else if (k < data_plus_mac_plus_padding_size + header_length)
-				b = data[k-header_length];
-			k++;
-
-			is_past_c = is_block_a & constant_time_ge(j, c);
-			is_past_cp1 = is_block_a & constant_time_ge(j, c+1);
-			/* If this is the block containing the end of the
-			 * application data, and we are at the offset for the
-			 * 0x80 value, then overwrite b with 0x80. */
-			b = (b&~is_past_c) | (0x80&is_past_c);
-			/* If this the the block containing the end of the
-			 * application data and we're past the 0x80 value then
-			 * just write zero. */
-			b = b&~is_past_cp1;
-			/* If this is index_b (the final block), but not
-			 * index_a (the end of the data), then the 64-bit
-			 * length didn't fit into index_a and we're having to
-			 * add an extra block of zeros. */
-			b &= ~is_block_b | is_block_a;
-
-			/* The final bytes of one of the blocks contains the
-			 * length. */
-			if (j >= md_block_size - md_length_size)
-				{
-				/* If this is index_b, write a length byte. */
-				b = (b&~is_block_b) | (is_block_b&length_bytes[j-(md_block_size-md_length_size)]);
-				}
-			block[j] = b;
-			}
-
-		md_transform(md_state.c, block);
-		md_final_raw(md_state.c, block);
-		/* If this is index_b, copy the hash value to |mac_out|. */
-		for (j = 0; j < md_size; j++)
-			mac_out[j] |= block[j]&is_block_b;
-		}
-
-	EVP_MD_CTX_init(&md_ctx);
-	EVP_DigestInit_ex(&md_ctx, ctx->digest, NULL /* engine */);
-	if (is_sslv3)
-		{
-		/* We repurpose |hmac_pad| to contain the SSLv3 pad2 block. */
-		memset(hmac_pad, 0x5c, sslv3_pad_length);
-
-		EVP_DigestUpdate(&md_ctx, mac_secret, mac_secret_length);
-		EVP_DigestUpdate(&md_ctx, hmac_pad, sslv3_pad_length);
-		EVP_DigestUpdate(&md_ctx, mac_out, md_size);
-		}
-	else
-		{
-		/* Complete the HMAC in the standard manner. */
-		for (i = 0; i < md_block_size; i++)
-			hmac_pad[i] ^= 0x6a;
-
-		EVP_DigestUpdate(&md_ctx, hmac_pad, md_block_size);
-		EVP_DigestUpdate(&md_ctx, mac_out, md_size);
-		}
-	EVP_DigestFinal(&md_ctx, md_out, &md_out_size_u);
-	if (md_out_size)
-		*md_out_size = md_out_size_u;
-	EVP_MD_CTX_cleanup(&md_ctx);
-	}
-
-#ifdef OPENSSL_FIPS
-
-/* Due to the need to use EVP in FIPS mode we can't reimplement digests but
- * we can ensure the number of blocks processed is equal for all cases
- * by digesting additional data.
- */
-
-void tls_fips_digest_extra(
-	const EVP_CIPHER_CTX *cipher_ctx, EVP_MD_CTX *mac_ctx,
-	const unsigned char *data, size_t data_len, size_t orig_len)
-	{
-	size_t block_size, digest_pad, blocks_data, blocks_orig;
-	if (EVP_CIPHER_CTX_mode(cipher_ctx) != EVP_CIPH_CBC_MODE)
-		return;
-	block_size = EVP_MD_CTX_block_size(mac_ctx);
-	/* We are in FIPS mode if we get this far so we know we have only SHA*
-	 * digests and TLS to deal with.
-	 * Minimum digest padding length is 17 for SHA384/SHA512 and 9
-	 * otherwise.
-	 * Additional header is 13 bytes. To get the number of digest blocks
-	 * processed round up the amount of data plus padding to the nearest
-	 * block length. Block length is 128 for SHA384/SHA512 and 64 otherwise.
-	 * So we have:
-	 * blocks = (payload_len + digest_pad + 13 + block_size - 1)/block_size
-	 * equivalently:
-	 * blocks = (payload_len + digest_pad + 12)/block_size + 1
-	 * HMAC adds a constant overhead.
-	 * We're ultimately only interested in differences so this becomes
-	 * blocks = (payload_len + 29)/128
-	 * for SHA384/SHA512 and
-	 * blocks = (payload_len + 21)/64
-	 * otherwise.
-	 */
-	digest_pad = block_size == 64 ? 21 : 29;
-	blocks_orig = (orig_len + digest_pad)/block_size;
-	blocks_data = (data_len + digest_pad)/block_size;
-	/* MAC enough blocks to make up the difference between the original
-	 * and actual lengths plus one extra block to ensure this is never a
-	 * no op. The "data" pointer should always have enough space to
-	 * perform this operation as it is large enough for a maximum
-	 * length TLS buffer. 
-	 */
-	EVP_DigestSignUpdate(mac_ctx, data,
-				(blocks_orig - blocks_data + 1) * block_size);
-	}
-#endif