1 /* Copyright (c) 2014, Google Inc.
3 * Permission to use, copy, modify, and/or distribute this software for any
4 * purpose with or without fee is hereby granted, provided that the above
5 * copyright notice and this permission notice appear in all copies.
7 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
8 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
9 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
10 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
11 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
12 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
13 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
19 #include <openssl/aead.h>
20 #include <openssl/cipher.h>
21 #include <openssl/err.h>
22 #include <openssl/hmac.h>
23 #include <openssl/md5.h>
24 #include <openssl/mem.h>
25 #include <openssl/sha.h>
28 #include "../internal.h"
29 #include "../fipsmodule/cipher/internal.h"
33 EVP_CIPHER_CTX cipher_ctx;
37 static int ssl3_mac(AEAD_SSL3_CTX *ssl3_ctx, uint8_t *out, unsigned *out_len,
38 const uint8_t *ad, size_t ad_len, const uint8_t *in,
40 size_t md_size = EVP_MD_CTX_size(&ssl3_ctx->md_ctx);
41 size_t pad_len = (md_size == 20) ? 40 : 48;
43 // To allow for CBC mode which changes cipher length, |ad| doesn't include the
44 // length for legacy ciphers.
46 ad_extra[0] = (uint8_t)(in_len >> 8);
47 ad_extra[1] = (uint8_t)(in_len & 0xff);
50 EVP_MD_CTX_init(&md_ctx);
53 uint8_t tmp[EVP_MAX_MD_SIZE];
54 OPENSSL_memset(pad, 0x36, pad_len);
55 if (!EVP_MD_CTX_copy_ex(&md_ctx, &ssl3_ctx->md_ctx) ||
56 !EVP_DigestUpdate(&md_ctx, pad, pad_len) ||
57 !EVP_DigestUpdate(&md_ctx, ad, ad_len) ||
58 !EVP_DigestUpdate(&md_ctx, ad_extra, sizeof(ad_extra)) ||
59 !EVP_DigestUpdate(&md_ctx, in, in_len) ||
60 !EVP_DigestFinal_ex(&md_ctx, tmp, NULL)) {
61 EVP_MD_CTX_cleanup(&md_ctx);
65 OPENSSL_memset(pad, 0x5c, pad_len);
66 if (!EVP_MD_CTX_copy_ex(&md_ctx, &ssl3_ctx->md_ctx) ||
67 !EVP_DigestUpdate(&md_ctx, pad, pad_len) ||
68 !EVP_DigestUpdate(&md_ctx, tmp, md_size) ||
69 !EVP_DigestFinal_ex(&md_ctx, out, out_len)) {
70 EVP_MD_CTX_cleanup(&md_ctx);
73 EVP_MD_CTX_cleanup(&md_ctx);
77 static void aead_ssl3_cleanup(EVP_AEAD_CTX *ctx) {
78 AEAD_SSL3_CTX *ssl3_ctx = (AEAD_SSL3_CTX *)ctx->aead_state;
79 EVP_CIPHER_CTX_cleanup(&ssl3_ctx->cipher_ctx);
80 EVP_MD_CTX_cleanup(&ssl3_ctx->md_ctx);
81 OPENSSL_free(ssl3_ctx);
82 ctx->aead_state = NULL;
85 static int aead_ssl3_init(EVP_AEAD_CTX *ctx, const uint8_t *key, size_t key_len,
86 size_t tag_len, enum evp_aead_direction_t dir,
87 const EVP_CIPHER *cipher, const EVP_MD *md) {
88 if (tag_len != EVP_AEAD_DEFAULT_TAG_LENGTH &&
89 tag_len != EVP_MD_size(md)) {
90 OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_UNSUPPORTED_TAG_SIZE);
94 if (key_len != EVP_AEAD_key_length(ctx->aead)) {
95 OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BAD_KEY_LENGTH);
99 size_t mac_key_len = EVP_MD_size(md);
100 size_t enc_key_len = EVP_CIPHER_key_length(cipher);
101 assert(mac_key_len + enc_key_len + EVP_CIPHER_iv_length(cipher) == key_len);
103 AEAD_SSL3_CTX *ssl3_ctx = OPENSSL_malloc(sizeof(AEAD_SSL3_CTX));
104 if (ssl3_ctx == NULL) {
105 OPENSSL_PUT_ERROR(CIPHER, ERR_R_MALLOC_FAILURE);
108 EVP_CIPHER_CTX_init(&ssl3_ctx->cipher_ctx);
109 EVP_MD_CTX_init(&ssl3_ctx->md_ctx);
111 ctx->aead_state = ssl3_ctx;
112 if (!EVP_CipherInit_ex(&ssl3_ctx->cipher_ctx, cipher, NULL, &key[mac_key_len],
113 &key[mac_key_len + enc_key_len],
114 dir == evp_aead_seal) ||
115 !EVP_DigestInit_ex(&ssl3_ctx->md_ctx, md, NULL) ||
116 !EVP_DigestUpdate(&ssl3_ctx->md_ctx, key, mac_key_len)) {
117 aead_ssl3_cleanup(ctx);
118 ctx->aead_state = NULL;
121 EVP_CIPHER_CTX_set_padding(&ssl3_ctx->cipher_ctx, 0);
126 static size_t aead_ssl3_tag_len(const EVP_AEAD_CTX *ctx, const size_t in_len,
127 const size_t extra_in_len) {
128 assert(extra_in_len == 0);
129 const AEAD_SSL3_CTX *ssl3_ctx = (AEAD_SSL3_CTX*)ctx->aead_state;
131 const size_t digest_len = EVP_MD_CTX_size(&ssl3_ctx->md_ctx);
132 if (EVP_CIPHER_CTX_mode(&ssl3_ctx->cipher_ctx) != EVP_CIPH_CBC_MODE) {
137 const size_t block_size = EVP_CIPHER_CTX_block_size(&ssl3_ctx->cipher_ctx);
138 // An overflow of |in_len + digest_len| doesn't affect the result mod
139 // |block_size|, provided that |block_size| is a smaller power of two.
140 assert(block_size != 0 && (block_size & (block_size - 1)) == 0);
141 const size_t pad_len = block_size - ((in_len + digest_len) % block_size);
142 return digest_len + pad_len;
145 static int aead_ssl3_seal_scatter(const EVP_AEAD_CTX *ctx, uint8_t *out,
146 uint8_t *out_tag, size_t *out_tag_len,
147 const size_t max_out_tag_len,
148 const uint8_t *nonce, const size_t nonce_len,
149 const uint8_t *in, const size_t in_len,
150 const uint8_t *extra_in,
151 const size_t extra_in_len, const uint8_t *ad,
152 const size_t ad_len) {
153 AEAD_SSL3_CTX *ssl3_ctx = (AEAD_SSL3_CTX *)ctx->aead_state;
155 if (!ssl3_ctx->cipher_ctx.encrypt) {
156 // Unlike a normal AEAD, an SSL3 AEAD may only be used in one direction.
157 OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_INVALID_OPERATION);
161 if (in_len > INT_MAX) {
162 // EVP_CIPHER takes int as input.
163 OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_TOO_LARGE);
167 if (max_out_tag_len < aead_ssl3_tag_len(ctx, in_len, extra_in_len)) {
168 OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BUFFER_TOO_SMALL);
172 if (nonce_len != 0) {
173 OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_IV_TOO_LARGE);
177 if (ad_len != 11 - 2 /* length bytes */) {
178 OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_INVALID_AD_SIZE);
182 // Compute the MAC. This must be first in case the operation is being done
184 uint8_t mac[EVP_MAX_MD_SIZE];
186 if (!ssl3_mac(ssl3_ctx, mac, &mac_len, ad, ad_len, in, in_len)) {
190 // Encrypt the input.
192 if (!EVP_EncryptUpdate(&ssl3_ctx->cipher_ctx, out, &len, in,
197 const size_t block_size = EVP_CIPHER_CTX_block_size(&ssl3_ctx->cipher_ctx);
199 // Feed the MAC into the cipher in two steps. First complete the final partial
200 // block from encrypting the input and split the result between |out| and
201 // |out_tag|. Then encrypt the remainder.
203 size_t early_mac_len = (block_size - (in_len % block_size)) % block_size;
204 if (early_mac_len != 0) {
205 assert(len + block_size - early_mac_len == in_len);
206 uint8_t buf[EVP_MAX_BLOCK_LENGTH];
208 if (!EVP_EncryptUpdate(&ssl3_ctx->cipher_ctx, buf, &buf_len, mac,
209 (int)early_mac_len)) {
212 assert(buf_len == (int)block_size);
213 OPENSSL_memcpy(out + len, buf, block_size - early_mac_len);
214 OPENSSL_memcpy(out_tag, buf + block_size - early_mac_len, early_mac_len);
216 size_t tag_len = early_mac_len;
218 if (!EVP_EncryptUpdate(&ssl3_ctx->cipher_ctx, out_tag + tag_len, &len,
219 mac + tag_len, mac_len - tag_len)) {
224 if (block_size > 1) {
225 assert(block_size <= 256);
226 assert(EVP_CIPHER_CTX_mode(&ssl3_ctx->cipher_ctx) == EVP_CIPH_CBC_MODE);
228 // Compute padding and feed that into the cipher.
229 uint8_t padding[256];
230 size_t padding_len = block_size - ((in_len + mac_len) % block_size);
231 OPENSSL_memset(padding, 0, padding_len - 1);
232 padding[padding_len - 1] = padding_len - 1;
233 if (!EVP_EncryptUpdate(&ssl3_ctx->cipher_ctx, out_tag + tag_len, &len, padding,
240 if (!EVP_EncryptFinal_ex(&ssl3_ctx->cipher_ctx, out_tag + tag_len, &len)) {
244 assert(tag_len == aead_ssl3_tag_len(ctx, in_len, extra_in_len));
246 *out_tag_len = tag_len;
250 static int aead_ssl3_open(const EVP_AEAD_CTX *ctx, uint8_t *out,
251 size_t *out_len, size_t max_out_len,
252 const uint8_t *nonce, size_t nonce_len,
253 const uint8_t *in, size_t in_len,
254 const uint8_t *ad, size_t ad_len) {
255 AEAD_SSL3_CTX *ssl3_ctx = (AEAD_SSL3_CTX *)ctx->aead_state;
257 if (ssl3_ctx->cipher_ctx.encrypt) {
258 // Unlike a normal AEAD, an SSL3 AEAD may only be used in one direction.
259 OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_INVALID_OPERATION);
263 size_t mac_len = EVP_MD_CTX_size(&ssl3_ctx->md_ctx);
264 if (in_len < mac_len) {
265 OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BAD_DECRYPT);
269 if (max_out_len < in_len) {
270 // This requires that the caller provide space for the MAC, even though it
271 // will always be removed on return.
272 OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BUFFER_TOO_SMALL);
276 if (nonce_len != 0) {
277 OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_TOO_LARGE);
281 if (ad_len != 11 - 2 /* length bytes */) {
282 OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_INVALID_AD_SIZE);
286 if (in_len > INT_MAX) {
287 // EVP_CIPHER takes int as input.
288 OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_TOO_LARGE);
292 // Decrypt to get the plaintext + MAC + padding.
295 if (!EVP_DecryptUpdate(&ssl3_ctx->cipher_ctx, out, &len, in, (int)in_len)) {
299 if (!EVP_DecryptFinal_ex(&ssl3_ctx->cipher_ctx, out + total, &len)) {
303 assert(total == in_len);
305 // Remove CBC padding and MAC. This would normally be timing-sensitive, but
306 // SSLv3 CBC ciphers are already broken. Support will be removed eventually.
307 // https://www.openssl.org/~bodo/ssl-poodle.pdf
309 if (EVP_CIPHER_CTX_mode(&ssl3_ctx->cipher_ctx) == EVP_CIPH_CBC_MODE) {
310 unsigned padding_length = out[total - 1];
311 if (total < padding_length + 1 + mac_len) {
312 OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BAD_DECRYPT);
315 // The padding must be minimal.
316 if (padding_length + 1 > EVP_CIPHER_CTX_block_size(&ssl3_ctx->cipher_ctx)) {
317 OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BAD_DECRYPT);
320 data_len = total - padding_length - 1 - mac_len;
322 data_len = total - mac_len;
325 // Compute the MAC and compare against the one in the record.
326 uint8_t mac[EVP_MAX_MD_SIZE];
327 if (!ssl3_mac(ssl3_ctx, mac, NULL, ad, ad_len, out, data_len)) {
330 if (CRYPTO_memcmp(&out[data_len], mac, mac_len) != 0) {
331 OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BAD_DECRYPT);
339 static int aead_ssl3_get_iv(const EVP_AEAD_CTX *ctx, const uint8_t **out_iv,
340 size_t *out_iv_len) {
341 AEAD_SSL3_CTX *ssl3_ctx = (AEAD_SSL3_CTX *)ctx->aead_state;
342 const size_t iv_len = EVP_CIPHER_CTX_iv_length(&ssl3_ctx->cipher_ctx);
347 *out_iv = ssl3_ctx->cipher_ctx.iv;
348 *out_iv_len = iv_len;
352 static int aead_aes_128_cbc_sha1_ssl3_init(EVP_AEAD_CTX *ctx, const uint8_t *key,
353 size_t key_len, size_t tag_len,
354 enum evp_aead_direction_t dir) {
355 return aead_ssl3_init(ctx, key, key_len, tag_len, dir, EVP_aes_128_cbc(),
359 static int aead_aes_256_cbc_sha1_ssl3_init(EVP_AEAD_CTX *ctx, const uint8_t *key,
360 size_t key_len, size_t tag_len,
361 enum evp_aead_direction_t dir) {
362 return aead_ssl3_init(ctx, key, key_len, tag_len, dir, EVP_aes_256_cbc(),
365 static int aead_des_ede3_cbc_sha1_ssl3_init(EVP_AEAD_CTX *ctx,
366 const uint8_t *key, size_t key_len,
368 enum evp_aead_direction_t dir) {
369 return aead_ssl3_init(ctx, key, key_len, tag_len, dir, EVP_des_ede3_cbc(),
373 static int aead_null_sha1_ssl3_init(EVP_AEAD_CTX *ctx, const uint8_t *key,
374 size_t key_len, size_t tag_len,
375 enum evp_aead_direction_t dir) {
376 return aead_ssl3_init(ctx, key, key_len, tag_len, dir, EVP_enc_null(),
380 static const EVP_AEAD aead_aes_128_cbc_sha1_ssl3 = {
381 SHA_DIGEST_LENGTH + 16 + 16, // key len (SHA1 + AES128 + IV)
383 16 + SHA_DIGEST_LENGTH, // overhead (padding + SHA1)
384 SHA_DIGEST_LENGTH, // max tag length
385 0, // seal_scatter_supports_extra_in
388 aead_aes_128_cbc_sha1_ssl3_init,
391 aead_ssl3_seal_scatter,
397 static const EVP_AEAD aead_aes_256_cbc_sha1_ssl3 = {
398 SHA_DIGEST_LENGTH + 32 + 16, // key len (SHA1 + AES256 + IV)
400 16 + SHA_DIGEST_LENGTH, // overhead (padding + SHA1)
401 SHA_DIGEST_LENGTH, // max tag length
402 0, // seal_scatter_supports_extra_in
405 aead_aes_256_cbc_sha1_ssl3_init,
408 aead_ssl3_seal_scatter,
414 static const EVP_AEAD aead_des_ede3_cbc_sha1_ssl3 = {
415 SHA_DIGEST_LENGTH + 24 + 8, // key len (SHA1 + 3DES + IV)
417 8 + SHA_DIGEST_LENGTH, // overhead (padding + SHA1)
418 SHA_DIGEST_LENGTH, // max tag length
419 0, // seal_scatter_supports_extra_in
422 aead_des_ede3_cbc_sha1_ssl3_init,
425 aead_ssl3_seal_scatter,
431 static const EVP_AEAD aead_null_sha1_ssl3 = {
432 SHA_DIGEST_LENGTH, // key len
434 SHA_DIGEST_LENGTH, // overhead (SHA1)
435 SHA_DIGEST_LENGTH, // max tag length
436 0, // seal_scatter_supports_extra_in
439 aead_null_sha1_ssl3_init,
442 aead_ssl3_seal_scatter,
448 const EVP_AEAD *EVP_aead_aes_128_cbc_sha1_ssl3(void) {
449 return &aead_aes_128_cbc_sha1_ssl3;
452 const EVP_AEAD *EVP_aead_aes_256_cbc_sha1_ssl3(void) {
453 return &aead_aes_256_cbc_sha1_ssl3;
456 const EVP_AEAD *EVP_aead_des_ede3_cbc_sha1_ssl3(void) {
457 return &aead_des_ede3_cbc_sha1_ssl3;
460 const EVP_AEAD *EVP_aead_null_sha1_ssl3(void) { return &aead_null_sha1_ssl3; }