/** Test AES-CTR encryption and decryption with IV. */
static void
test_crypto_aes_iv(void *arg)
{
char *plain, *encrypted1, *encrypted2, *decrypted1, *decrypted2;
char plain_1[1], plain_15[15], plain_16[16], plain_17[17];
char key1[16], key2[16];
ssize_t encrypted_size, decrypted_size;
int use_evp = !strcmp(arg,"evp");
evaluate_evp_for_aes(use_evp);
plain = tor_malloc(4095);
encrypted1 = tor_malloc(4095 + 1 + 16);
encrypted2 = tor_malloc(4095 + 1 + 16);
decrypted1 = tor_malloc(4095 + 1);
decrypted2 = tor_malloc(4095 + 1);
crypto_rand(plain, 4095);
crypto_rand(key1, 16);
crypto_rand(key2, 16);
crypto_rand(plain_1, 1);
crypto_rand(plain_15, 15);
crypto_rand(plain_16, 16);
crypto_rand(plain_17, 17);
key1[0] = key2[0] + 128; /* Make sure that contents are different. */
/* Encrypt and decrypt with the same key. */
encrypted_size = crypto_cipher_encrypt_with_iv(key1, encrypted1, 16 + 4095,
plain, 4095);
test_eq(encrypted_size, 16 + 4095);
tt_assert(encrypted_size > 0); /* This is obviously true, since 4111 is
* greater than 0, but its truth is not
* obvious to all analysis tools. */
decrypted_size = crypto_cipher_decrypt_with_iv(key1, decrypted1, 4095,
encrypted1, encrypted_size);
test_eq(decrypted_size, 4095);
tt_assert(decrypted_size > 0);
test_memeq(plain, decrypted1, 4095);
/* Encrypt a second time (with a new random initialization vector). */
encrypted_size = crypto_cipher_encrypt_with_iv(key1, encrypted2, 16 + 4095,
plain, 4095);
test_eq(encrypted_size, 16 + 4095);
tt_assert(encrypted_size > 0);
decrypted_size = crypto_cipher_decrypt_with_iv(key1, decrypted2, 4095,
encrypted2, encrypted_size);
test_eq(decrypted_size, 4095);
tt_assert(decrypted_size > 0);
test_memeq(plain, decrypted2, 4095);
test_memneq(encrypted1, encrypted2, encrypted_size);
/* Decrypt with the wrong key. */
decrypted_size = crypto_cipher_decrypt_with_iv(key2, decrypted2, 4095,
encrypted1, encrypted_size);
test_memneq(plain, decrypted2, decrypted_size);
/* Alter the initialization vector. */
encrypted1[0] += 42;
decrypted_size = crypto_cipher_decrypt_with_iv(key1, decrypted1, 4095,
encrypted1, encrypted_size);
test_memneq(plain, decrypted2, 4095);
/* Special length case: 1. */
encrypted_size = crypto_cipher_encrypt_with_iv(key1, encrypted1, 16 + 1,
plain_1, 1);
test_eq(encrypted_size, 16 + 1);
tt_assert(encrypted_size > 0);
decrypted_size = crypto_cipher_decrypt_with_iv(key1, decrypted1, 1,
encrypted1, encrypted_size);
test_eq(decrypted_size, 1);
tt_assert(decrypted_size > 0);
test_memeq(plain_1, decrypted1, 1);
/* Special length case: 15. */
encrypted_size = crypto_cipher_encrypt_with_iv(key1, encrypted1, 16 + 15,
plain_15, 15);
test_eq(encrypted_size, 16 + 15);
tt_assert(encrypted_size > 0);
decrypted_size = crypto_cipher_decrypt_with_iv(key1, decrypted1, 15,
encrypted1, encrypted_size);
test_eq(decrypted_size, 15);
tt_assert(decrypted_size > 0);
test_memeq(plain_15, decrypted1, 15);
/* Special length case: 16. */
encrypted_size = crypto_cipher_encrypt_with_iv(key1, encrypted1, 16 + 16,
plain_16, 16);
test_eq(encrypted_size, 16 + 16);
tt_assert(encrypted_size > 0);
decrypted_size = crypto_cipher_decrypt_with_iv(key1, decrypted1, 16,
encrypted1, encrypted_size);
test_eq(decrypted_size, 16);
tt_assert(decrypted_size > 0);
test_memeq(plain_16, decrypted1, 16);
/* Special length case: 17. */
encrypted_size = crypto_cipher_encrypt_with_iv(key1, encrypted1, 16 + 17,
plain_17, 17);
test_eq(encrypted_size, 16 + 17);
tt_assert(encrypted_size > 0);
decrypted_size = crypto_cipher_decrypt_with_iv(key1, decrypted1, 17,
encrypted1, encrypted_size);
test_eq(decrypted_size, 17);
tt_assert(decrypted_size > 0);
test_memeq(plain_17, decrypted1, 17);
done:
/* Free memory. */
tor_free(plain);
tor_free(encrypted1);
tor_free(encrypted2);
tor_free(decrypted1);
tor_free(decrypted2);
}
/** Decrypt the encrypted introduction points in <b>ipos_encrypted</b> of
* length <b>ipos_encrypted_size</b> using <b>descriptor_cookie</b> and
* write the result to a newly allocated string that is pointed to by
* <b>ipos_decrypted</b> and its length to <b>ipos_decrypted_size</b>.
* Return 0 if decryption was successful and -1 otherwise. */
int
rend_decrypt_introduction_points(char **ipos_decrypted,
size_t *ipos_decrypted_size,
const char *descriptor_cookie,
const char *ipos_encrypted,
size_t ipos_encrypted_size)
{
tor_assert(ipos_encrypted);
tor_assert(descriptor_cookie);
if (ipos_encrypted_size < 2) {
log_warn(LD_REND, "Size of encrypted introduction points is too "
"small.");
return -1;
}
if (ipos_encrypted[0] == (int)REND_BASIC_AUTH) {
char iv[CIPHER_IV_LEN], client_id[REND_BASIC_AUTH_CLIENT_ID_LEN],
session_key[CIPHER_KEY_LEN], *dec;
int declen, client_blocks;
size_t pos = 0, len, client_entries_len;
crypto_digest_t *digest;
crypto_cipher_t *cipher;
client_blocks = (int) ipos_encrypted[1];
client_entries_len = client_blocks * REND_BASIC_AUTH_CLIENT_MULTIPLE *
REND_BASIC_AUTH_CLIENT_ENTRY_LEN;
if (ipos_encrypted_size < 2 + client_entries_len + CIPHER_IV_LEN + 1) {
log_warn(LD_REND, "Size of encrypted introduction points is too "
"small.");
return -1;
}
memcpy(iv, ipos_encrypted + 2 + client_entries_len, CIPHER_IV_LEN);
digest = crypto_digest_new();
crypto_digest_add_bytes(digest, descriptor_cookie, REND_DESC_COOKIE_LEN);
crypto_digest_add_bytes(digest, iv, CIPHER_IV_LEN);
crypto_digest_get_digest(digest, client_id,
REND_BASIC_AUTH_CLIENT_ID_LEN);
crypto_digest_free(digest);
for (pos = 2; pos < 2 + client_entries_len;
pos += REND_BASIC_AUTH_CLIENT_ENTRY_LEN) {
if (tor_memeq(ipos_encrypted + pos, client_id,
REND_BASIC_AUTH_CLIENT_ID_LEN)) {
/* Attempt to decrypt introduction points. */
cipher = crypto_cipher_new(descriptor_cookie);
if (crypto_cipher_decrypt(cipher, session_key, ipos_encrypted
+ pos + REND_BASIC_AUTH_CLIENT_ID_LEN,
CIPHER_KEY_LEN) < 0) {
log_warn(LD_REND, "Could not decrypt session key for client.");
crypto_cipher_free(cipher);
return -1;
}
crypto_cipher_free(cipher);
len = ipos_encrypted_size - 2 - client_entries_len - CIPHER_IV_LEN;
dec = tor_malloc_zero(len + 1);
declen = crypto_cipher_decrypt_with_iv(session_key, dec, len,
ipos_encrypted + 2 + client_entries_len,
ipos_encrypted_size - 2 - client_entries_len);
if (declen < 0) {
log_warn(LD_REND, "Could not decrypt introduction point string.");
tor_free(dec);
return -1;
}
if (fast_memcmpstart(dec, declen, "introduction-point ")) {
log_warn(LD_REND, "Decrypted introduction points don't "
"look like we could parse them.");
tor_free(dec);
continue;
}
*ipos_decrypted = dec;
*ipos_decrypted_size = declen;
return 0;
}
}
log_warn(LD_REND, "Could not decrypt introduction points. Please "
"check your authorization for this service!");
return -1;
} else if (ipos_encrypted[0] == (int)REND_STEALTH_AUTH) {
char *dec;
int declen;
if (ipos_encrypted_size < CIPHER_IV_LEN + 2) {
log_warn(LD_REND, "Size of encrypted introduction points is too "
"small.");
return -1;
}
dec = tor_malloc_zero(ipos_encrypted_size - CIPHER_IV_LEN - 1 + 1);
declen = crypto_cipher_decrypt_with_iv(descriptor_cookie, dec,
ipos_encrypted_size -
CIPHER_IV_LEN - 1,
ipos_encrypted + 1,
ipos_encrypted_size - 1);
if (declen < 0) {
log_warn(LD_REND, "Decrypting introduction points failed!");
tor_free(dec);
return -1;
}
*ipos_decrypted = dec;
*ipos_decrypted_size = declen;
return 0;
} else {
log_warn(LD_REND, "Unknown authorization type number: %d",
ipos_encrypted[0]);
return -1;
}
}
