|
- /* Copyright (c) 2014, Google Inc.
- *
- * Permission to use, copy, modify, and/or distribute this software for any
- * purpose with or without fee is hereby granted, provided that the above
- * copyright notice and this permission notice appear in all copies.
- *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
- * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
- * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
- * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
-
- #include <assert.h>
- #include <limits.h>
- #include <string.h>
-
- #include <openssl/aead.h>
- #include <openssl/cipher.h>
- #include <openssl/err.h>
- #include <openssl/hmac.h>
- #include <openssl/md5.h>
- #include <openssl/mem.h>
- #include <openssl/sha.h>
-
- #include "internal.h"
-
-
- typedef struct {
- EVP_CIPHER_CTX cipher_ctx;
- EVP_MD_CTX md_ctx;
- } AEAD_SSL3_CTX;
-
- static int ssl3_mac(AEAD_SSL3_CTX *ssl3_ctx, uint8_t *out, unsigned *out_len,
- const uint8_t *ad, size_t ad_len, const uint8_t *in,
- size_t in_len) {
- size_t md_size = EVP_MD_CTX_size(&ssl3_ctx->md_ctx);
- size_t pad_len = (md_size == 20) ? 40 : 48;
-
- /* To allow for CBC mode which changes cipher length, |ad| doesn't include the
- * length for legacy ciphers. */
- uint8_t ad_extra[2];
- ad_extra[0] = (uint8_t)(in_len >> 8);
- ad_extra[1] = (uint8_t)(in_len & 0xff);
-
- EVP_MD_CTX md_ctx;
- EVP_MD_CTX_init(&md_ctx);
-
- uint8_t pad[48];
- uint8_t tmp[EVP_MAX_MD_SIZE];
- memset(pad, 0x36, pad_len);
- if (!EVP_MD_CTX_copy_ex(&md_ctx, &ssl3_ctx->md_ctx) ||
- !EVP_DigestUpdate(&md_ctx, pad, pad_len) ||
- !EVP_DigestUpdate(&md_ctx, ad, ad_len) ||
- !EVP_DigestUpdate(&md_ctx, ad_extra, sizeof(ad_extra)) ||
- !EVP_DigestUpdate(&md_ctx, in, in_len) ||
- !EVP_DigestFinal_ex(&md_ctx, tmp, NULL)) {
- EVP_MD_CTX_cleanup(&md_ctx);
- return 0;
- }
-
- memset(pad, 0x5c, pad_len);
- if (!EVP_MD_CTX_copy_ex(&md_ctx, &ssl3_ctx->md_ctx) ||
- !EVP_DigestUpdate(&md_ctx, pad, pad_len) ||
- !EVP_DigestUpdate(&md_ctx, tmp, md_size) ||
- !EVP_DigestFinal_ex(&md_ctx, out, out_len)) {
- EVP_MD_CTX_cleanup(&md_ctx);
- return 0;
- }
- EVP_MD_CTX_cleanup(&md_ctx);
- return 1;
- }
-
- static void aead_ssl3_cleanup(EVP_AEAD_CTX *ctx) {
- AEAD_SSL3_CTX *ssl3_ctx = (AEAD_SSL3_CTX *)ctx->aead_state;
- EVP_CIPHER_CTX_cleanup(&ssl3_ctx->cipher_ctx);
- EVP_MD_CTX_cleanup(&ssl3_ctx->md_ctx);
- OPENSSL_free(ssl3_ctx);
- ctx->aead_state = NULL;
- }
-
- static int aead_ssl3_init(EVP_AEAD_CTX *ctx, const uint8_t *key, size_t key_len,
- size_t tag_len, enum evp_aead_direction_t dir,
- const EVP_CIPHER *cipher, const EVP_MD *md) {
- if (tag_len != EVP_AEAD_DEFAULT_TAG_LENGTH &&
- tag_len != EVP_MD_size(md)) {
- OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_UNSUPPORTED_TAG_SIZE);
- return 0;
- }
-
- if (key_len != EVP_AEAD_key_length(ctx->aead)) {
- OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BAD_KEY_LENGTH);
- return 0;
- }
-
- size_t mac_key_len = EVP_MD_size(md);
- size_t enc_key_len = EVP_CIPHER_key_length(cipher);
- assert(mac_key_len + enc_key_len + EVP_CIPHER_iv_length(cipher) == key_len);
- /* Although EVP_rc4() is a variable-length cipher, the default key size is
- * correct for SSL3. */
-
- AEAD_SSL3_CTX *ssl3_ctx = OPENSSL_malloc(sizeof(AEAD_SSL3_CTX));
- if (ssl3_ctx == NULL) {
- OPENSSL_PUT_ERROR(CIPHER, ERR_R_MALLOC_FAILURE);
- return 0;
- }
- EVP_CIPHER_CTX_init(&ssl3_ctx->cipher_ctx);
- EVP_MD_CTX_init(&ssl3_ctx->md_ctx);
-
- ctx->aead_state = ssl3_ctx;
- if (!EVP_CipherInit_ex(&ssl3_ctx->cipher_ctx, cipher, NULL, &key[mac_key_len],
- &key[mac_key_len + enc_key_len],
- dir == evp_aead_seal) ||
- !EVP_DigestInit_ex(&ssl3_ctx->md_ctx, md, NULL) ||
- !EVP_DigestUpdate(&ssl3_ctx->md_ctx, key, mac_key_len)) {
- aead_ssl3_cleanup(ctx);
- ctx->aead_state = NULL;
- return 0;
- }
- EVP_CIPHER_CTX_set_padding(&ssl3_ctx->cipher_ctx, 0);
-
- return 1;
- }
-
- static int aead_ssl3_seal(const EVP_AEAD_CTX *ctx, uint8_t *out,
- size_t *out_len, size_t max_out_len,
- const uint8_t *nonce, size_t nonce_len,
- const uint8_t *in, size_t in_len,
- const uint8_t *ad, size_t ad_len) {
- AEAD_SSL3_CTX *ssl3_ctx = (AEAD_SSL3_CTX *)ctx->aead_state;
- size_t total = 0;
-
- if (!ssl3_ctx->cipher_ctx.encrypt) {
- /* Unlike a normal AEAD, an SSL3 AEAD may only be used in one direction. */
- OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_INVALID_OPERATION);
- return 0;
- }
-
- if (in_len + EVP_AEAD_max_overhead(ctx->aead) < in_len ||
- in_len > INT_MAX) {
- /* EVP_CIPHER takes int as input. */
- OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_TOO_LARGE);
- return 0;
- }
-
- if (max_out_len < in_len + EVP_AEAD_max_overhead(ctx->aead)) {
- OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BUFFER_TOO_SMALL);
- return 0;
- }
-
- if (nonce_len != 0) {
- OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_IV_TOO_LARGE);
- return 0;
- }
-
- if (ad_len != 11 - 2 /* length bytes */) {
- OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_INVALID_AD_SIZE);
- return 0;
- }
-
- /* Compute the MAC. This must be first in case the operation is being done
- * in-place. */
- uint8_t mac[EVP_MAX_MD_SIZE];
- unsigned mac_len;
- if (!ssl3_mac(ssl3_ctx, mac, &mac_len, ad, ad_len, in, in_len)) {
- return 0;
- }
-
- /* Encrypt the input. */
- int len;
- if (!EVP_EncryptUpdate(&ssl3_ctx->cipher_ctx, out, &len, in,
- (int)in_len)) {
- return 0;
- }
- total = len;
-
- /* Feed the MAC into the cipher. */
- if (!EVP_EncryptUpdate(&ssl3_ctx->cipher_ctx, out + total, &len, mac,
- (int)mac_len)) {
- return 0;
- }
- total += len;
-
- unsigned block_size = EVP_CIPHER_CTX_block_size(&ssl3_ctx->cipher_ctx);
- if (block_size > 1) {
- assert(block_size <= 256);
- assert(EVP_CIPHER_CTX_mode(&ssl3_ctx->cipher_ctx) == EVP_CIPH_CBC_MODE);
-
- /* Compute padding and feed that into the cipher. */
- uint8_t padding[256];
- unsigned padding_len = block_size - ((in_len + mac_len) % block_size);
- memset(padding, 0, padding_len - 1);
- padding[padding_len - 1] = padding_len - 1;
- if (!EVP_EncryptUpdate(&ssl3_ctx->cipher_ctx, out + total, &len, padding,
- (int)padding_len)) {
- return 0;
- }
- total += len;
- }
-
- if (!EVP_EncryptFinal_ex(&ssl3_ctx->cipher_ctx, out + total, &len)) {
- return 0;
- }
- total += len;
-
- *out_len = total;
- return 1;
- }
-
- static int aead_ssl3_open(const EVP_AEAD_CTX *ctx, uint8_t *out,
- size_t *out_len, size_t max_out_len,
- const uint8_t *nonce, size_t nonce_len,
- const uint8_t *in, size_t in_len,
- const uint8_t *ad, size_t ad_len) {
- AEAD_SSL3_CTX *ssl3_ctx = (AEAD_SSL3_CTX *)ctx->aead_state;
-
- if (ssl3_ctx->cipher_ctx.encrypt) {
- /* Unlike a normal AEAD, an SSL3 AEAD may only be used in one direction. */
- OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_INVALID_OPERATION);
- return 0;
- }
-
- size_t mac_len = EVP_MD_CTX_size(&ssl3_ctx->md_ctx);
- if (in_len < mac_len) {
- OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BAD_DECRYPT);
- return 0;
- }
-
- if (max_out_len < in_len) {
- /* This requires that the caller provide space for the MAC, even though it
- * will always be removed on return. */
- OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BUFFER_TOO_SMALL);
- return 0;
- }
-
- if (nonce_len != 0) {
- OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_TOO_LARGE);
- return 0;
- }
-
- if (ad_len != 11 - 2 /* length bytes */) {
- OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_INVALID_AD_SIZE);
- return 0;
- }
-
- if (in_len > INT_MAX) {
- /* EVP_CIPHER takes int as input. */
- OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_TOO_LARGE);
- return 0;
- }
-
- /* Decrypt to get the plaintext + MAC + padding. */
- size_t total = 0;
- int len;
- if (!EVP_DecryptUpdate(&ssl3_ctx->cipher_ctx, out, &len, in, (int)in_len)) {
- return 0;
- }
- total += len;
- if (!EVP_DecryptFinal_ex(&ssl3_ctx->cipher_ctx, out + total, &len)) {
- return 0;
- }
- total += len;
- assert(total == in_len);
-
- /* Remove CBC padding and MAC. This would normally be timing-sensitive, but SSLv3 CBC
- * ciphers are already broken. Support will be removed eventually.
- * https://www.openssl.org/~bodo/ssl-poodle.pdf */
- unsigned data_len;
- if (EVP_CIPHER_CTX_mode(&ssl3_ctx->cipher_ctx) == EVP_CIPH_CBC_MODE) {
- unsigned padding_length = out[total - 1];
- if (total < padding_length + 1 + mac_len) {
- OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BAD_DECRYPT);
- return 0;
- }
- /* The padding must be minimal. */
- if (padding_length + 1 > EVP_CIPHER_CTX_block_size(&ssl3_ctx->cipher_ctx)) {
- OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BAD_DECRYPT);
- return 0;
- }
- data_len = total - padding_length - 1 - mac_len;
- } else {
- data_len = total - mac_len;
- }
-
- /* Compute the MAC and compare against the one in the record. */
- uint8_t mac[EVP_MAX_MD_SIZE];
- if (!ssl3_mac(ssl3_ctx, mac, NULL, ad, ad_len, out, data_len)) {
- return 0;
- }
- if (CRYPTO_memcmp(&out[data_len], mac, mac_len) != 0) {
- OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BAD_DECRYPT);
- return 0;
- }
-
- *out_len = data_len;
- return 1;
- }
-
- static int aead_ssl3_get_rc4_state(const EVP_AEAD_CTX *ctx, const RC4_KEY **out_key) {
- AEAD_SSL3_CTX *ssl3_ctx = (AEAD_SSL3_CTX *)ctx->aead_state;
- if (EVP_CIPHER_CTX_cipher(&ssl3_ctx->cipher_ctx) != EVP_rc4()) {
- return 0;
- }
-
- *out_key = (RC4_KEY*) ssl3_ctx->cipher_ctx.cipher_data;
- return 1;
- }
-
- static int aead_rc4_md5_ssl3_init(EVP_AEAD_CTX *ctx, const uint8_t *key,
- size_t key_len, size_t tag_len,
- enum evp_aead_direction_t dir) {
- return aead_ssl3_init(ctx, key, key_len, tag_len, dir, EVP_rc4(), EVP_md5());
- }
-
- static int aead_rc4_sha1_ssl3_init(EVP_AEAD_CTX *ctx, const uint8_t *key,
- size_t key_len, size_t tag_len,
- enum evp_aead_direction_t dir) {
- return aead_ssl3_init(ctx, key, key_len, tag_len, dir, EVP_rc4(), EVP_sha1());
- }
-
- static int aead_aes_128_cbc_sha1_ssl3_init(EVP_AEAD_CTX *ctx, const uint8_t *key,
- size_t key_len, size_t tag_len,
- enum evp_aead_direction_t dir) {
- return aead_ssl3_init(ctx, key, key_len, tag_len, dir, EVP_aes_128_cbc(),
- EVP_sha1());
- }
-
- static int aead_aes_256_cbc_sha1_ssl3_init(EVP_AEAD_CTX *ctx, const uint8_t *key,
- size_t key_len, size_t tag_len,
- enum evp_aead_direction_t dir) {
- return aead_ssl3_init(ctx, key, key_len, tag_len, dir, EVP_aes_256_cbc(),
- EVP_sha1());
- }
- static int aead_des_ede3_cbc_sha1_ssl3_init(EVP_AEAD_CTX *ctx,
- const uint8_t *key, size_t key_len,
- size_t tag_len,
- enum evp_aead_direction_t dir) {
- return aead_ssl3_init(ctx, key, key_len, tag_len, dir, EVP_des_ede3_cbc(),
- EVP_sha1());
- }
-
- static const EVP_AEAD aead_rc4_md5_ssl3 = {
- MD5_DIGEST_LENGTH + 16, /* key len (MD5 + RC4) */
- 0, /* nonce len */
- MD5_DIGEST_LENGTH, /* overhead */
- MD5_DIGEST_LENGTH, /* max tag length */
- NULL, /* init */
- aead_rc4_md5_ssl3_init,
- aead_ssl3_cleanup,
- aead_ssl3_seal,
- aead_ssl3_open,
- aead_ssl3_get_rc4_state,
- };
-
- static const EVP_AEAD aead_rc4_sha1_ssl3 = {
- SHA_DIGEST_LENGTH + 16, /* key len (SHA1 + RC4) */
- 0, /* nonce len */
- SHA_DIGEST_LENGTH, /* overhead */
- SHA_DIGEST_LENGTH, /* max tag length */
- NULL, /* init */
- aead_rc4_sha1_ssl3_init,
- aead_ssl3_cleanup,
- aead_ssl3_seal,
- aead_ssl3_open,
- aead_ssl3_get_rc4_state,
- };
-
- static const EVP_AEAD aead_aes_128_cbc_sha1_ssl3 = {
- SHA_DIGEST_LENGTH + 16 + 16, /* key len (SHA1 + AES128 + IV) */
- 0, /* nonce len */
- 16 + SHA_DIGEST_LENGTH, /* overhead (padding + SHA1) */
- SHA_DIGEST_LENGTH, /* max tag length */
- NULL, /* init */
- aead_aes_128_cbc_sha1_ssl3_init,
- aead_ssl3_cleanup,
- aead_ssl3_seal,
- aead_ssl3_open,
- NULL, /* get_rc4_state */
- };
-
- static const EVP_AEAD aead_aes_256_cbc_sha1_ssl3 = {
- SHA_DIGEST_LENGTH + 32 + 16, /* key len (SHA1 + AES256 + IV) */
- 0, /* nonce len */
- 16 + SHA_DIGEST_LENGTH, /* overhead (padding + SHA1) */
- SHA_DIGEST_LENGTH, /* max tag length */
- NULL, /* init */
- aead_aes_256_cbc_sha1_ssl3_init,
- aead_ssl3_cleanup,
- aead_ssl3_seal,
- aead_ssl3_open,
- NULL, /* get_rc4_state */
- };
-
- static const EVP_AEAD aead_des_ede3_cbc_sha1_ssl3 = {
- SHA_DIGEST_LENGTH + 24 + 8, /* key len (SHA1 + 3DES + IV) */
- 0, /* nonce len */
- 8 + SHA_DIGEST_LENGTH, /* overhead (padding + SHA1) */
- SHA_DIGEST_LENGTH, /* max tag length */
- NULL, /* init */
- aead_des_ede3_cbc_sha1_ssl3_init,
- aead_ssl3_cleanup,
- aead_ssl3_seal,
- aead_ssl3_open,
- NULL, /* get_rc4_state */
- };
-
- const EVP_AEAD *EVP_aead_rc4_md5_ssl3(void) { return &aead_rc4_md5_ssl3; }
-
- const EVP_AEAD *EVP_aead_rc4_sha1_ssl3(void) { return &aead_rc4_sha1_ssl3; }
-
- const EVP_AEAD *EVP_aead_aes_128_cbc_sha1_ssl3(void) {
- return &aead_aes_128_cbc_sha1_ssl3;
- }
-
- const EVP_AEAD *EVP_aead_aes_256_cbc_sha1_ssl3(void) {
- return &aead_aes_256_cbc_sha1_ssl3;
- }
-
- const EVP_AEAD *EVP_aead_des_ede3_cbc_sha1_ssl3(void) {
- return &aead_des_ede3_cbc_sha1_ssl3;
- }
|