mirror of
https://github.com/openssl/openssl.git
synced 2024-12-27 06:21:43 +08:00
781aa7ab63
Use of the low level MD5 functions has been informally discouraged for a long time. We now formally deprecate them. Reviewed-by: Matt Caswell <matt@openssl.org> (Merged from https://github.com/openssl/openssl/pull/10791)
494 lines
18 KiB
C
494 lines
18 KiB
C
/*
|
|
* Copyright 2012-2019 The OpenSSL Project Authors. All Rights Reserved.
|
|
*
|
|
* Licensed under the Apache License 2.0 (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
|
|
*/
|
|
|
|
/*
|
|
* MD5 and SHA-1 low level APIs are deprecated for public use, but still ok for
|
|
* internal use.
|
|
*/
|
|
#include "internal/deprecated.h"
|
|
|
|
#include "internal/constant_time.h"
|
|
#include "ssl_local.h"
|
|
#include "internal/cryptlib.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
|
|
|
|
/*
|
|
* 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);
|
|
}
|
|
|
|
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);
|
|
}
|
|
}
|
|
|
|
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 preceding 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. )
|
|
* Returns 1 on success or 0 on error
|
|
*/
|
|
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 {
|
|
OSSL_UNION_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);
|
|
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;
|
|
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];
|
|
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.
|
|
*/
|
|
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.
|
|
*/
|
|
if (!ossl_assert(data_plus_mac_plus_padding_size < 1024 * 1024))
|
|
return 0;
|
|
|
|
switch (EVP_MD_CTX_type(ctx)) {
|
|
case NID_md5:
|
|
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;
|
|
md_size = 16;
|
|
sslv3_pad_length = 48;
|
|
length_is_big_endian = 0;
|
|
break;
|
|
case NID_sha1:
|
|
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;
|
|
case NID_sha224:
|
|
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:
|
|
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;
|
|
case NID_sha384:
|
|
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_size = 384 / 8;
|
|
md_block_size = 128;
|
|
md_length_size = 16;
|
|
break;
|
|
case NID_sha512:
|
|
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_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.
|
|
*/
|
|
if (md_out_size != NULL)
|
|
*md_out_size = 0;
|
|
return ossl_assert(0);
|
|
}
|
|
|
|
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) {
|
|
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 |variance_blocks|
|
|
* 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 : ( ((255 + 1 + md_size + md_block_size - 1) / md_block_size) + 1);
|
|
/*
|
|
* 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);
|
|
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;
|
|
|
|
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) {
|
|
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). 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
|
|
*/
|
|
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);
|
|
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_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 = 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_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
|
|
* overwrite b with 0x80.
|
|
*/
|
|
b = constant_time_select_8(is_past_c, 0x80, b);
|
|
/*
|
|
* 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;
|
|
/*
|
|
* 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;
|
|
}
|
|
|
|
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);
|
|
|
|
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;
|
|
|
|
if (EVP_DigestUpdate(md_ctx, hmac_pad, md_block_size) <= 0
|
|
|| EVP_DigestUpdate(md_ctx, mac_out, md_size) <= 0)
|
|
goto err;
|
|
}
|
|
/* 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_free(md_ctx);
|
|
|
|
return 1;
|
|
err:
|
|
EVP_MD_CTX_free(md_ctx);
|
|
return 0;
|
|
}
|