1 files changed, 0 insertions, 704 deletions
diff --git a/src/lib/libssl/s3_cbc.c b/src/lib/libssl/s3_cbc.c
deleted file mode 100644
index fd4781b64c..0000000000
--- a/src/lib/libssl/s3_cbc.c
+++ /dev/null
@@ -1,704 +0,0 @@
-/* $OpenBSD: s3_cbc.c,v 1.9 2014/12/15 00:46:53 doug Exp $ */
-/* ====================================================================
- * 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 (SSL_USE_EXPLICIT_IV(s)) {
-                /* 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]
-         * (We don't support compression either, so it's not in operation.)
-         */
-        if ((s->options & SSL_OP_TLS_BLOCK_PADDING_BUG)) {
-                /* First packet is even in size, so check */
-                if ((memcmp(s->s3->read_sequence, "\0\0\0\0\0\0\0\0",
-                    SSL3_SEQUENCE_SIZE) == 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
-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
-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
-/* 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)
-{
-        switch (EVP_MD_CTX_type(ctx)) {
-        case NID_md5:
-        case NID_sha1:
-        case NID_sha224:
-        case NID_sha256:
-        case NID_sha384:
-        case NID_sha512:
-                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. ) */
-int
-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;
-        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;
-        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;
-        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 = 0;
-                return 0;
-        }
-        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);
-        if (!EVP_DigestInit_ex(&md_ctx, ctx->digest, NULL /* engine */)) {
-                EVP_MD_CTX_cleanup(&md_ctx);
-                return 0;
-        }
-        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);
-        return 1;
-}