X-Git-Url: https://git.openssl.org/gitweb/?p=openssl.git;a=blobdiff_plain;f=ssl%2Fs3_cbc.c;h=85f296b8078398c083cb69b498e9f71af31ffd82;hp=bffaebb0c219934fcfcae0a0c80e2a8d290834be;hb=HEAD;hpb=3fddbb264e87a8cef2903cbd7b02b8e1a39a2a99 diff --git a/ssl/s3_cbc.c b/ssl/s3_cbc.c deleted file mode 100644 index bffaebb0c2..0000000000 --- a/ssl/s3_cbc.c +++ /dev/null @@ -1,535 +0,0 @@ -/* - * Copyright 2012-2020 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 - */ - -/* - * This file has no dependencies on the rest of libssl because it is shared - * with the providers. It contains functions for low level MAC calculations. - * Responsibility for this lies with the HMAC implementation in the - * providers. However there are legacy code paths in libssl which also need to - * do this. In time those legacy code paths can be removed and this file can be - * moved out of libssl. - */ - - -/* - * 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 "internal/cryptlib.h" - -#include -#include -#include - -char ssl3_cbc_record_digest_supported(const EVP_MD_CTX *ctx); -int ssl3_cbc_digest_record(const EVP_MD *md, - 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); - -# define l2n(l,c) (*((c)++)=(unsigned char)(((l)>>24)&0xff), \ - *((c)++)=(unsigned char)(((l)>>16)&0xff), \ - *((c)++)=(unsigned char)(((l)>> 8)&0xff), \ - *((c)++)=(unsigned char)(((l) )&0xff)) - -# define l2n6(l,c) (*((c)++)=(unsigned char)(((l)>>40)&0xff), \ - *((c)++)=(unsigned char)(((l)>>32)&0xff), \ - *((c)++)=(unsigned char)(((l)>>24)&0xff), \ - *((c)++)=(unsigned char)(((l)>>16)&0xff), \ - *((c)++)=(unsigned char)(((l)>> 8)&0xff), \ - *((c)++)=(unsigned char)(((l) )&0xff)) - -# define l2n8(l,c) (*((c)++)=(unsigned char)(((l)>>56)&0xff), \ - *((c)++)=(unsigned char)(((l)>>48)&0xff), \ - *((c)++)=(unsigned char)(((l)>>40)&0xff), \ - *((c)++)=(unsigned char)(((l)>>32)&0xff), \ - *((c)++)=(unsigned char)(((l)>>24)&0xff), \ - *((c)++)=(unsigned char)(((l)>>16)&0xff), \ - *((c)++)=(unsigned char)(((l)>> 8)&0xff), \ - *((c)++)=(unsigned char)(((l) )&0xff)) - -/* - * 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 serializes 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 *md, - 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 = 0; - - /* - * 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_type(md)) { - 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, md, 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; - - ret = 1; - err: - EVP_MD_CTX_free(md_ctx); - return ret; -}