Reformatting of s3_{cbc|clnt}.c

Change-Id: Ie873bdf0dd5a66e76e6ebf909b1f1fe29b6fa611

1 files changed, 438 insertions, 459 deletions

diff --git a/ssl/s3_cbc.c b/ssl/s3_cbc.c
index 510d4809..418a04fe 100644
--- a/ssl/s3_cbc.c
+++ b/ssl/s3_cbc.c
@@ -76,27 +76,25 @@
  *   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 constant_time_select_int(good, 1, -1);
+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 constant_time_select_int(good, 1, -1);
 }
 
 /* tls1_cbc_remove_padding removes the CBC padding from the decrypted, TLS, CBC
@@ -110,64 +108,61 @@ int ssl3_cbc_remove_padding(const SSL* s,
  *   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];
-
-	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 = 256; /* maximum amount of padding, inc length byte. */
-	if (to_check > rec->length)
-		to_check = rec->length;
-
-	for (i = 0; i < to_check; i++)
-		{
-		unsigned char mask = constant_time_ge_8(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. */
-	good = constant_time_eq(0xff, good & 0xff);
-
-	padding_length = good & (padding_length+1);
-	rec->length -= padding_length;
-	rec->type |= padding_length<<8;	/* kludge: pass padding length */
-
-	return constant_time_select_int(good, 1, -1);
-	}
+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];
+
+  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 = 256; /* maximum amount of padding, inc length byte. */
+  if (to_check > rec->length) {
+    to_check = rec->length;
+  }
+
+  for (i = 0; i < to_check; i++) {
+    unsigned char mask = constant_time_ge_8(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. */
+  good = constant_time_eq(0xff, good & 0xff);
+
+  padding_length = good & (padding_length + 1);
+  rec->length -= padding_length;
+  rec->type |= padding_length << 8; /* kludge: pass padding length */
+
+  return constant_time_select_int(good, 1, -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
@@ -188,144 +183,135 @@ int tls1_cbc_remove_padding(const SSL* s,
  */
 #define CBC_MAC_ROTATE_IN_PLACE
 
-void ssl3_cbc_copy_mac(unsigned char* out,
-		       const SSL3_RECORD *rec,
-		       unsigned md_size,unsigned orig_len)
-	{
+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;
+  unsigned char rotated_mac_buf[64 + EVP_MAX_MD_SIZE];
+  unsigned char *rotated_mac;
 #else
-	unsigned char rotated_mac[EVP_MAX_MD_SIZE];
+  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;
+  /* 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;
 
-	assert(orig_len >= md_size);
-	assert(md_size <= EVP_MAX_MD_SIZE);
+  assert(orig_len >= md_size);
+  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);
+  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_8(i, mac_start);
-		unsigned char mac_ended = constant_time_ge_8(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 */
+  /* 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_8(i, mac_start);
+    unsigned char mac_ended = constant_time_ge_8(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);
-		}
+  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);
-		}
+  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))
+  (*((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_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);
-	}
+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;
+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);
-		}
-	}
+  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;
+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);
-		}
-	}
+  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_sha1:
-		case NID_sha256:
-		case NID_sha384:
-			return 1;
-		default:
-			return 0;
-		}
-	}
+char ssl3_cbc_record_digest_supported(const EVP_MD_CTX *ctx) {
+  switch (EVP_MD_CTX_type(ctx)) {
+    case NID_sha1:
+    case NID_sha256:
+    case NID_sha384:
+      return 1;
+
+    default:
+      return 0;
+  }
+}
 
 /* ssl3_cbc_digest_record computes the MAC of a decrypted, padded SSLv3/TLS
  * record.
@@ -346,277 +332,270 @@ char ssl3_cbc_record_digest_supported(const EVP_MD_CTX *ctx)
  * 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;
-
-	/* This is a, hopefully redundant, check that allows us to forget about
-	 * many possible overflows later in this function. */
-	assert(data_plus_mac_plus_padding_size < 1024*1024);
-
-	switch (EVP_MD_CTX_type(ctx))
-		{
-		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_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;
-		default:
-			/* ssl3_cbc_record_digest_supported should have been
-			 * called first to check that the hash function is
-			 * supported. */
-			assert(0);
-			*md_out_size = 0;
-			return 0;
-		}
-
-	assert(md_length_size <= MAX_HASH_BIT_COUNT_BYTES);
-	assert(md_block_size <= MAX_HASH_BLOCK_SIZE);
-	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);
-		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);
-		}
-
-	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;
-
-	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: 7 bytes (SHA1). */
-			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_8(j, c);
-			is_past_cp1 = is_block_a & constant_time_ge_8(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 = constant_time_select_8(is_past_c, 0x80, b);
-			/* 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 = constant_time_select_8(is_block_b, length_bytes[j-(md_block_size-md_length_size)], b);
-				}
-			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);
-	*md_out_size = md_out_size_u;
-	EVP_MD_CTX_cleanup(&md_ctx);
-
-	return 1;
-	}
+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;
+
+  /* This is a, hopefully redundant, check that allows us to forget about
+   * many possible overflows later in this function. */
+  assert(data_plus_mac_plus_padding_size < 1024 * 1024);
+
+  switch (EVP_MD_CTX_type(ctx)) {
+    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_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;
+
+    default:
+      /* ssl3_cbc_record_digest_supported should have been
+       * called first to check that the hash function is
+       * supported. */
+      assert(0);
+      *md_out_size = 0;
+      return 0;
+  }
+
+  assert(md_length_size <= MAX_HASH_BIT_COUNT_BYTES);
+  assert(md_block_size <= MAX_HASH_BLOCK_SIZE);
+  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);
+    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);
+  }
+
+  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;
+
+  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: 7 bytes (SHA1). */
+      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_8(j, c);
+      is_past_cp1 = is_block_a & constant_time_ge_8(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 = constant_time_select_8(is_past_c, 0x80, b);
+      /* 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 = constant_time_select_8(
+            is_block_b, length_bytes[j - (md_block_size - md_length_size)], b);
+      }
+      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);
+  *md_out_size = md_out_size_u;
+  EVP_MD_CTX_cleanup(&md_ctx);
+
+  return 1;
+}