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Removed aes_crypt, left only aes_crypt_inplace. Removed should_use_openssl_CTR, was used for openssl 1.0.0 bug.

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This commit is contained in:
Malek 2016-02-06 12:05:32 -05:00 committed by Nick Mathewson
parent 1f5cdf2b6c
commit a9cd291753
3 changed files with 27 additions and 142 deletions
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159
src/common/aes.c
View File

@ -101,18 +101,6 @@ aes_cipher_free(aes_cnt_cipher_t *cipher_)
EVP_CIPHER_CTX_free(cipher);
}
void
aes_crypt(aes_cnt_cipher_t *cipher_, const char *input, size_t len,
char *output)
{
int outl;
EVP_CIPHER_CTX *cipher = (EVP_CIPHER_CTX *) cipher_;
tor_assert(len < INT_MAX);
EVP_EncryptUpdate(cipher, (unsigned char*)output,
&outl, (const unsigned char *)input, (int)len);
}
void
aes_crypt_inplace(aes_cnt_cipher_t *cipher_, char *data, size_t len)
{
int outl;
@ -181,10 +169,6 @@ struct aes_cnt_cipher {
* we're testing it or because we have hardware acceleration configured */
static int should_use_EVP = 0;
/** True iff we have tested the counter-mode implementation and found that it
* doesn't have the counter-mode bug from OpenSSL 1.0.0. */
static int should_use_openssl_CTR = 0;
/** Check whether we should use the EVP interface for AES. If <b>force_val</b>
* is nonnegative, we use use EVP iff it is true. Otherwise, we use EVP
* if there is an engine enabled for aes-ecb. */
@ -249,13 +233,9 @@ evaluate_ctr_for_aes(void)
if (fast_memneq(output, encrypt_zero, 16)) {
/* Counter mode is buggy */
log_notice(LD_CRYPTO, "This OpenSSL has a buggy version of counter mode; "
"not using it.");
} else {
/* Counter mode is okay */
log_info(LD_CRYPTO, "This OpenSSL has a good implementation of counter "
"mode; using it.");
should_use_openssl_CTR = 1;
log_err(LD_CRYPTO, "This OpenSSL has a buggy version of counter mode; "
"quitting tor.");
exit(1);
}
return 0;
}
@ -266,29 +246,6 @@ evaluate_ctr_for_aes(void)
#define COUNTER(c, n) ((c)->counter ## n)
#endif
/**
* Helper function: set <b>cipher</b>'s internal buffer to the encrypted
* value of the current counter.
*/
static inline void
aes_fill_buf_(aes_cnt_cipher_t *cipher)
{
/* We don't currently use OpenSSL's counter mode implementation because:
* 1) some versions have known bugs
* 2) its attitude towards IVs is not our own
* 3) changing the counter position was not trivial, last time I looked.
* None of these issues are insurmountable in principle.
*/
if (cipher->using_evp) {
int outl=16, inl=16;
EVP_EncryptUpdate(&cipher->key.evp, cipher->buf, &outl,
cipher->ctr_buf.buf, inl);
} else {
AES_encrypt(cipher->ctr_buf.buf, cipher->buf, &cipher->key.aes);
}
}
static void aes_set_key(aes_cnt_cipher_t *cipher, const char *key,
int key_bits);
static void aes_set_iv(aes_cnt_cipher_t *cipher, const char *iv);
@ -341,10 +298,7 @@ aes_set_key(aes_cnt_cipher_t *cipher, const char *key, int key_bits)
cipher->pos = 0;
if (should_use_openssl_CTR)
memset(cipher->buf, 0, sizeof(cipher->buf));
else
aes_fill_buf_(cipher);
memset(cipher->buf, 0, sizeof(cipher->buf));
}
/** Release storage held by <b>cipher</b>
@ -380,63 +334,6 @@ evp_block128_fn(const uint8_t in[16],
EVP_EncryptUpdate(ctx, out, &outl, in, inl);
}
/** Encrypt <b>len</b> bytes from <b>input</b>, storing the result in
* <b>output</b>. Uses the key in <b>cipher</b>, and advances the counter
* by <b>len</b> bytes as it encrypts.
*/
void
aes_crypt(aes_cnt_cipher_t *cipher, const char *input, size_t len,
char *output)
{
if (should_use_openssl_CTR) {
if (cipher->using_evp) {
/* In openssl 1.0.0, there's an if'd out EVP_aes_128_ctr in evp.h. If
* it weren't disabled, it might be better just to use that.
*/
CRYPTO_ctr128_encrypt((const unsigned char *)input,
(unsigned char *)output,
len,
&cipher->key.evp,
cipher->ctr_buf.buf,
cipher->buf,
&cipher->pos,
evp_block128_fn);
} else {
AES_ctr128_encrypt((const unsigned char *)input,
(unsigned char *)output,
len,
&cipher->key.aes,
cipher->ctr_buf.buf,
cipher->buf,
&cipher->pos);
}
return;
} else {
int c = cipher->pos;
if (PREDICT_UNLIKELY(!len)) return;
while (1) {
do {
if (len-- == 0) { cipher->pos = c; return; }
*(output++) = *(input++) ^ cipher->buf[c];
} while (++c != 16);
cipher->pos = c = 0;
if (PREDICT_UNLIKELY(! ++COUNTER(cipher, 0))) {
if (PREDICT_UNLIKELY(! ++COUNTER(cipher, 1))) {
if (PREDICT_UNLIKELY(! ++COUNTER(cipher, 2))) {
++COUNTER(cipher, 3);
UPDATE_CTR_BUF(cipher, 3);
}
UPDATE_CTR_BUF(cipher, 2);
}
UPDATE_CTR_BUF(cipher, 1);
}
UPDATE_CTR_BUF(cipher, 0);
aes_fill_buf_(cipher);
}
}
}
/** Encrypt <b>len</b> bytes from <b>input</b>, storing the results in place.
* Uses the key in <b>cipher</b>, and advances the counter by <b>len</b> bytes
* as it encrypts.
@ -444,32 +341,26 @@ aes_crypt(aes_cnt_cipher_t *cipher, const char *input, size_t len,
void
aes_crypt_inplace(aes_cnt_cipher_t *cipher, char *data, size_t len)
{
if (should_use_openssl_CTR) {
aes_crypt(cipher, data, len, data);
return;
if (cipher->using_evp) {
/* In openssl 1.0.0, there's an if'd out EVP_aes_128_ctr in evp.h. If
* it weren't disabled, it might be better just to use that.
*/
CRYPTO_ctr128_encrypt((const unsigned char *)data,
(unsigned char *)data,
len,
&cipher->key.evp,
cipher->ctr_buf.buf,
cipher->buf,
&cipher->pos,
evp_block128_fn);
} else {
int c = cipher->pos;
if (PREDICT_UNLIKELY(!len)) return;
while (1) {
do {
if (len-- == 0) { cipher->pos = c; return; }
*(data++) ^= cipher->buf[c];
} while (++c != 16);
cipher->pos = c = 0;
if (PREDICT_UNLIKELY(! ++COUNTER(cipher, 0))) {
if (PREDICT_UNLIKELY(! ++COUNTER(cipher, 1))) {
if (PREDICT_UNLIKELY(! ++COUNTER(cipher, 2))) {
++COUNTER(cipher, 3);
UPDATE_CTR_BUF(cipher, 3);
}
UPDATE_CTR_BUF(cipher, 2);
}
UPDATE_CTR_BUF(cipher, 1);
}
UPDATE_CTR_BUF(cipher, 0);
aes_fill_buf_(cipher);
}
AES_ctr128_encrypt((const unsigned char *)data,
(unsigned char *)data,
len,
&cipher->key.aes,
cipher->ctr_buf.buf,
cipher->buf,
&cipher->pos);
}
}
@ -486,10 +377,6 @@ aes_set_iv(aes_cnt_cipher_t *cipher, const char *iv)
#endif
cipher->pos = 0;
memcpy(cipher->ctr_buf.buf, iv, 16);
if (!should_use_openssl_CTR)
aes_fill_buf_(cipher);
}
#endif

3
src/common/aes.h
View File

@ -17,12 +17,9 @@ typedef struct aes_cnt_cipher aes_cnt_cipher_t;
aes_cnt_cipher_t* aes_new_cipher(const char *key, const char *iv);
void aes_cipher_free(aes_cnt_cipher_t *cipher);
void aes_crypt(aes_cnt_cipher_t *cipher, const char *input, size_t len,
char *output);
void aes_crypt_inplace(aes_cnt_cipher_t *cipher, char *data, size_t len);
int evaluate_evp_for_aes(int force_value);
int evaluate_ctr_for_aes(void);
#endif

7
src/common/crypto.c
View File

@ -1509,7 +1509,8 @@ crypto_cipher_encrypt(crypto_cipher_t *env, char *to,
tor_assert(to);
tor_assert(fromlen < SIZE_T_CEILING);
aes_crypt(env->cipher, from, fromlen, to);
memcpy(to, from, fromlen);
aes_crypt_inplace(env->cipher, to, fromlen);
return 0;
}
@ -1526,7 +1527,8 @@ crypto_cipher_decrypt(crypto_cipher_t *env, char *to,
tor_assert(to);
tor_assert(fromlen < SIZE_T_CEILING);
aes_crypt(env->cipher, from, fromlen, to);
memcpy(to, from, fromlen);
aes_crypt_inplace(env->cipher, to, fromlen);
return 0;
}
@ -3154,4 +3156,3 @@ crypto_global_cleanup(void)
}
/** @} */