-/* 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).
+/*
+ * Copyright 2012-2016 The OpenSSL Project Authors. All Rights Reserved.
*
+ * Licensed under the OpenSSL license (the "License"). You may not use
+ * this file except in compliance with the License. You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
*/
-#include "../crypto/constant_time_locl.h"
+#include "internal/constant_time_locl.h"
#include "ssl_locl.h"
+#include "internal/cryptlib.h"
#include <openssl/md5.h>
#include <openssl/sha.h>
*/
#define MAX_HASH_BLOCK_SIZE 128
-/*-
- * 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);
- rec->length -= good & (padding_length + 1);
- return constant_time_select_int(good, 1, -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;
- rec->orig_len -= 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_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);
- rec->length -= good & (padding_length + 1);
-
- 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
- * 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)
-{
-#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(rec->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 (rec->orig_len > md_size + 255 + 1)
- scan_start = rec->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 < rec->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);
- }
-#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.
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;
}
}
-# 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;
}
}
-# undef LARGEST_DIGEST_CTX
-# define LARGEST_DIGEST_CTX SHA512_CTX
-#endif
+#undef LARGEST_DIGEST_CTX
+#define LARGEST_DIGEST_CTX SHA512_CTX
/*
* ssl3_cbc_record_digest_supported returns 1 iff |ctx| uses a hash function
*/
char ssl3_cbc_record_digest_supported(const EVP_MD_CTX *ctx)
{
- if (FIPS_mode())
- return 0;
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;
* 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. )
+ * Returns 1 on success or 0 on error
*/
-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)
+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,
+ size_t mac_secret_length, char is_sslv3)
{
union {
double align;
} 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,
+ size_t md_size, md_block_size = 64;
+ size_t 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 */
+ size_t 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;
+ size_t i, j;
+ unsigned md_out_size_u;
+ EVP_MD_CTX *md_ctx = NULL;
/*
* mdLengthSize is the number of bytes in the length field that
* terminates * the hash.
*/
- unsigned md_length_size = 8;
+ size_t md_length_size = 8;
char length_is_big_endian = 1;
int ret;
* 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);
+ if (!ossl_assert(data_plus_mac_plus_padding_size < 1024 * 1024))
+ return 0;
switch (EVP_MD_CTX_type(ctx)) {
case NID_md5:
- MD5_Init((MD5_CTX *)md_state.c);
+ if (MD5_Init((MD5_CTX *)md_state.c) <= 0)
+ return 0;
md_final_raw = tls1_md5_final_raw;
md_transform =
(void (*)(void *ctx, const unsigned char *block))MD5_Transform;
length_is_big_endian = 0;
break;
case NID_sha1:
- SHA1_Init((SHA_CTX *)md_state.c);
+ if (SHA1_Init((SHA_CTX *)md_state.c) <= 0)
+ return 0;
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);
+ if (SHA224_Init((SHA256_CTX *)md_state.c) <= 0)
+ return 0;
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);
+ if (SHA256_Init((SHA256_CTX *)md_state.c) <= 0)
+ return 0;
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);
+ if (SHA384_Init((SHA512_CTX *)md_state.c) <= 0)
+ return 0;
md_final_raw = tls1_sha512_final_raw;
md_transform =
(void (*)(void *ctx, const unsigned char *block))SHA512_Transform;
md_length_size = 16;
break;
case NID_sha512:
- SHA512_Init((SHA512_CTX *)md_state.c);
+ if (SHA512_Init((SHA512_CTX *)md_state.c) <= 0)
+ return 0;
md_final_raw = tls1_sha512_final_raw;
md_transform =
(void (*)(void *ctx, const unsigned char *block))SHA512_Transform;
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;
+ if (md_out_size != NULL)
+ *md_out_size = 0;
+ return ossl_assert(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);
+ if (!ossl_assert(md_length_size <= MAX_HASH_BIT_COUNT_BYTES)
+ || !ossl_assert(md_block_size <= MAX_HASH_BLOCK_SIZE)
+ || !ossl_assert(md_size <= EVP_MAX_MD_SIZE))
+ return 0;
header_length = 13;
if (is_sslv3) {
*/
bits += 8 * md_block_size;
memset(hmac_pad, 0, md_block_size);
- OPENSSL_assert(mac_secret_length <= sizeof(hmac_pad));
+ if (!ossl_assert(mac_secret_length <= sizeof(hmac_pad)))
+ return 0;
memcpy(hmac_pad, mac_secret, mac_secret_length);
for (i = 0; i < md_block_size; i++)
hmac_pad[i] ^= 0x36;
if (k > 0) {
if (is_sslv3) {
+ size_t overhang;
+
/*
* 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).
+ * consumes: either 7 bytes (SHA1) or 11 bytes (MD5). There are no
+ * ciphersuites in SSLv3 that are not SHA1 or MD5 based and
+ * therefore we can be confident that the header_length will be
+ * greater than |md_block_size|. However we add a sanity check just
+ * in case
*/
- unsigned overhang = header_length - md_block_size;
+ if (header_length <= md_block_size) {
+ /* Should never happen */
+ return 0;
+ }
+ 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);
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);
+ unsigned char is_block_a = constant_time_eq_8_s(i, index_a);
+ unsigned char is_block_b = constant_time_eq_8_s(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 = 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);
+ is_past_c = is_block_a & constant_time_ge_8_s(j, c);
+ is_past_cp1 = is_block_a & constant_time_ge_8_s(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
*/
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.
+ * If this block contains the end of the application data
+ * and we're past the 0x80 value then just write zero.
*/
b = b & ~is_past_cp1;
/*
mac_out[j] |= block[j] & is_block_b;
}
- EVP_MD_CTX_init(&md_ctx);
- EVP_DigestInit_ex(&md_ctx, ctx->digest, NULL /* engine */ );
+ md_ctx = EVP_MD_CTX_new();
+ if (md_ctx == NULL)
+ goto err;
+ if (EVP_DigestInit_ex(md_ctx, EVP_MD_CTX_md(ctx), NULL /* engine */ ) <= 0)
+ goto err;
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);
+ if (EVP_DigestUpdate(md_ctx, mac_secret, mac_secret_length) <= 0
+ || EVP_DigestUpdate(md_ctx, hmac_pad, sslv3_pad_length) <= 0
+ || EVP_DigestUpdate(md_ctx, mac_out, md_size) <= 0)
+ goto err;
} 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);
+ if (EVP_DigestUpdate(md_ctx, hmac_pad, md_block_size) <= 0
+ || EVP_DigestUpdate(md_ctx, mac_out, md_size) <= 0)
+ goto err;
}
- ret = EVP_DigestFinal(&md_ctx, md_out, &md_out_size_u);
+ /* TODO(size_t): Convert me */
+ ret = EVP_DigestFinal(md_ctx, md_out, &md_out_size_u);
if (ret && md_out_size)
*md_out_size = md_out_size_u;
- EVP_MD_CTX_cleanup(&md_ctx);
-}
-
-/*
- * 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.
- */
+ EVP_MD_CTX_free(md_ctx);
-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);
+ return 1;
+ err:
+ EVP_MD_CTX_free(md_ctx);
+ return 0;
}
projects / openssl.git / blobdiff