| /* 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); |
| |
| 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 */ |
| size_t 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_iv(const EVP_AEAD_CTX *ctx, const uint8_t **out_iv, |
| size_t *out_iv_len) { |
| AEAD_SSL3_CTX *ssl3_ctx = (AEAD_SSL3_CTX *)ctx->aead_state; |
| const size_t iv_len = EVP_CIPHER_CTX_iv_length(&ssl3_ctx->cipher_ctx); |
| if (iv_len <= 1) { |
| return 0; |
| } |
| |
| *out_iv = ssl3_ctx->cipher_ctx.iv; |
| *out_iv_len = iv_len; |
| return 1; |
| } |
| |
| 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 int aead_null_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_enc_null(), |
| EVP_sha1()); |
| } |
| |
| 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, |
| aead_ssl3_get_iv, |
| }; |
| |
| 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, |
| aead_ssl3_get_iv, |
| }; |
| |
| 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, |
| aead_ssl3_get_iv, |
| }; |
| |
| static const EVP_AEAD aead_null_sha1_ssl3 = { |
| SHA_DIGEST_LENGTH, /* key len */ |
| 0, /* nonce len */ |
| SHA_DIGEST_LENGTH, /* overhead (SHA1) */ |
| SHA_DIGEST_LENGTH, /* max tag length */ |
| NULL, /* init */ |
| aead_null_sha1_ssl3_init, |
| aead_ssl3_cleanup, |
| aead_ssl3_seal, |
| aead_ssl3_open, |
| NULL, /* get_iv */ |
| }; |
| |
| 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; |
| } |
| |
| const EVP_AEAD *EVP_aead_null_sha1_ssl3(void) { return &aead_null_sha1_ssl3; } |