static
void test_static_v1_input_short(void)
{
ssize_t siz;
const struct hash_method *hash = hash_method_lookup("sha256");
unsigned char hash_ctx[hash->context_size];
unsigned char hash_dgst[hash->digest_size];
hash->init(hash_ctx);
test_begin("test_static_v1_input_short");
struct istream *is_1 = i_stream_create_file(DCRYPT_SRC_DIR"/sample-v1_short.asc", IO_BLOCK_SIZE);
struct istream *is_2 = i_stream_create_base64_decoder(is_1);
i_stream_unref(&is_1);
struct istream *is_3 = i_stream_create_decrypt(is_2, test_v1_kp.priv);
i_stream_unref(&is_2);
struct istream *is_4 = i_stream_create_hash(is_3, hash, hash_ctx);
i_stream_unref(&is_3);
while((siz = i_stream_read(is_4))>0) { i_stream_skip(is_4, siz); }
if (is_4->stream_errno != 0)
i_debug("error: %s", i_stream_get_error(is_4));
test_assert(is_4->stream_errno == 0);
i_stream_unref(&is_4);
hash->result(hash_ctx, hash_dgst);
test_assert(strcmp(test_sample_v1_short_hash, binary_to_hex(hash_dgst, sizeof(hash_dgst))) == 0);
test_end();
}
static
void test_static_v2_input(void)
{
test_begin("test_static_v2_input");
ssize_t amt;
const struct hash_method *hash = hash_method_lookup("sha256");
unsigned char hash_ctx[hash->context_size];
unsigned char hash_dgst[hash->digest_size];
hash->init(hash_ctx);
struct istream *is_1 = i_stream_create_file(DCRYPT_SRC_DIR"/sample-v2.asc", IO_BLOCK_SIZE);
struct istream *is_2 = i_stream_create_base64_decoder(is_1);
i_stream_unref(&is_1);
struct istream *is_3 = i_stream_create_decrypt(is_2, test_v2_kp.priv);
i_stream_unref(&is_2);
struct istream *is_4 = i_stream_create_hash(is_3, hash, hash_ctx);
i_stream_unref(&is_3);
while((amt = i_stream_read(is_4))>0) { i_stream_skip(is_4, amt); }
if (is_4->stream_errno != 0)
i_debug("error: %s", i_stream_get_error(is_4));
test_assert(is_4->stream_errno == 0);
i_stream_unref(&is_4);
hash->result(hash_ctx, hash_dgst);
test_assert(strcmp(test_sample_v2_hash, binary_to_hex(hash_dgst, sizeof(hash_dgst))) == 0);
test_end();
/** this code is left here to show how the sample file is created
struct istream *is = i_stream_create_file("../lib-fts/udhr_fra.txt", 8192);
struct istream *is_2 = i_stream_create_hash(is, hash, hash_ctx);
int fd = open("sample-v2.bin", O_CREAT|O_TRUNC|O_WRONLY, S_IRWXU);
struct ostream *os = o_stream_create_fd_file(fd, 0, TRUE);
struct ostream *os_2 = o_stream_create_encrypt(os, "aes-256-gcm-sha256", test_v2_kp.pub, IO_STREAM_ENC_INTEGRITY_AEAD);
const unsigned char *ptr;
size_t siz;
while(i_stream_read_data(is_2, &ptr, &siz, 0)>0) {
o_stream_nsend(os_2, ptr, siz);
i_stream_skip(is_2, siz);
}
i_assert(o_stream_nfinish(os_2)==0);
o_stream_close(os_2);
i_stream_close(is_2);
hash->result(hash_ctx, hash_dgst);
printf("%s\n", binary_to_hex(hash_dgst, sizeof(hash_dgst)));
*/
}
static void
pbkdf_run(const char *plaintext, const char *salt,
unsigned int rounds, unsigned char key_r[PBKDF2_KEY_SIZE_SHA1])
{
memset(key_r, 0, PBKDF2_KEY_SIZE_SHA1);
buffer_t buf;
buffer_create_from_data(&buf, key_r, PBKDF2_KEY_SIZE_SHA1);
pkcs5_pbkdf(PKCS5_PBKDF2, hash_method_lookup("sha1"),
(const unsigned char *)plaintext, strlen(plaintext),
(const unsigned char *)salt, strlen(salt),
rounds, PBKDF2_KEY_SIZE_SHA1, &buf);
}
static int
hash_format_parse(const char *str, unsigned int *idxp,
const struct hash_method **method_r,
unsigned int *bits_r, const char **error_r)
{
const char *name, *end, *bitsp;
unsigned int bits, i = *idxp;
/* we should have "hash_name}" or "hash_name:bits}" */
end = strchr(str+i, '}');
if (end == NULL) {
*error_r = "Missing '}'";
return -1;
}
*idxp = end - str;
name = t_strdup_until(str+i, end);
bitsp = strchr(name, ':');
if (bitsp != NULL)
name = t_strdup_until(name, bitsp++);
*method_r = hash_method_lookup(name);
if (*method_r == NULL) {
*error_r = t_strconcat("Unknown hash method: ", name, NULL);
return -1;
}
bits = (*method_r)->digest_size * 8;
if (bitsp != NULL) {
if (str_to_uint(bitsp, &bits) < 0 ||
bits == 0 || bits > (*method_r)->digest_size*8) {
*error_r = t_strconcat("Invalid :bits number: ",
bitsp, NULL);
return -1;
}
if ((bits % 8) != 0) {
*error_r = t_strconcat(
"Currently :bits must be divisible by 8: ",
bitsp, NULL);
return -1;
}
}
*bits_r = bits;
return 0;
}
static
ssize_t i_stream_decrypt_key(struct decrypt_istream *stream, const char *malg, unsigned int rounds,
const unsigned char *data, const unsigned char *end, buffer_t *key, size_t key_len)
{
const char *error;
enum dcrypt_key_type ktype;
int keys;
bool have_key = FALSE;
unsigned char dgst[32];
uint32_t val;
buffer_t buf;
if (data == end)
return 0;
keys = *data++;
/* if we have a key, prefab the digest */
if (stream->key_callback == NULL) {
if (stream->priv_key == NULL) {
io_stream_set_error(&stream->istream.iostream, "Decryption error: no private key available");
return -1;
}
buffer_create_from_data(&buf, dgst, sizeof(dgst));
dcrypt_key_id_private(stream->priv_key, "sha256", &buf, NULL);
}
/* for each key */
for(;keys>0;keys--) {
if ((size_t)(end-data) < 1 + (ssize_t)sizeof(dgst))
return 0;
ktype = *data++;
if (stream->key_callback != NULL) {
const char *hexdgst = binary_to_hex(data, sizeof(dgst)); /* digest length */
/* hope you going to give us right key.. */
int ret = stream->key_callback(hexdgst, &(stream->priv_key), &error, stream->key_context);
if (ret < 0) {
io_stream_set_error(&stream->istream.iostream, "Private key not available: %s", error);
return -1;
}
if (ret > 0) {
dcrypt_key_ref_private(stream->priv_key);
have_key = TRUE;
break;
}
} else {
/* see if key matches to the one we have */
if (memcmp(dgst, data, sizeof(dgst)) == 0) {
have_key = TRUE;
break;
}
}
data += sizeof(dgst);
/* wasn't correct key, skip over some data */
if (!get_msb32(&data, end, &val) ||
!get_msb32(&data, end, &val))
return 0;
}
/* didn't find matching key */
if (!have_key) {
io_stream_set_error(&stream->istream.iostream, "Decryption error: no private key available");
return -1;
}
data += sizeof(dgst);
const unsigned char *ephemeral_key;
uint32_t ep_key_len;
const unsigned char *encrypted_key;
uint32_t eklen;
const unsigned char *ekhash;
uint32_t ekhash_len;
/* read ephemeral key (can be missing for RSA) */
if (!get_msb32(&data, end, &ep_key_len) || (size_t)(end-data) < ep_key_len)
return 0;
ephemeral_key = data;
data += ep_key_len;
/* read encrypted key */
if (!get_msb32(&data, end, &eklen) || (size_t)(end-data) < eklen)
return 0;
encrypted_key = data;
data += eklen;
/* read key data hash */
if (!get_msb32(&data, end, &ekhash_len) || (size_t)(end-data) < ekhash_len)
return 0;
ekhash = data;
data += ekhash_len;
/* decrypt the seed */
if (ktype == DCRYPT_KEY_RSA) {
if (!dcrypt_rsa_decrypt(stream->priv_key, encrypted_key, eklen, key, &error)) {
io_stream_set_error(&stream->istream.iostream, "key decryption error: %s", error);
return -1;
}
} else if (ktype == DCRYPT_KEY_EC) {
/* perform ECDHE */
buffer_t *temp_key = buffer_create_dynamic(pool_datastack_create(), 256);
buffer_t *secret = buffer_create_dynamic(pool_datastack_create(), 256);
buffer_t peer_key;
buffer_create_from_const_data(&peer_key, ephemeral_key, ep_key_len);
if (!dcrypt_ecdh_derive_secret_local(stream->priv_key, &peer_key, secret, &error)) {
io_stream_set_error(&stream->istream.iostream, "Key decryption error: corrupted header");
return -1;
}
/* use shared secret and peer key to generate decryption key, AES-256-CBC has 32 byte key and 16 byte IV */
if (!dcrypt_pbkdf2(secret->data, secret->used, peer_key.data, peer_key.used,
malg, rounds, temp_key, 32+16, &error)) {
safe_memset(buffer_get_modifiable_data(secret, 0), 0, secret->used);
io_stream_set_error(&stream->istream.iostream, "Key decryption error: %s", error);
return -1;
}
safe_memset(buffer_get_modifiable_data(secret, 0), 0, secret->used);
if (temp_key->used != 32+16) {
safe_memset(buffer_get_modifiable_data(temp_key, 0), 0, temp_key->used);
io_stream_set_error(&stream->istream.iostream, "Cannot perform key decryption: invalid temporary key");
return -1;
}
struct dcrypt_context_symmetric *dctx;
if (!dcrypt_ctx_sym_create("AES-256-CBC", DCRYPT_MODE_DECRYPT, &dctx, &error)) {
safe_memset(buffer_get_modifiable_data(temp_key, 0), 0, temp_key->used);
io_stream_set_error(&stream->istream.iostream, "Key decryption error: %s", error);
return -1;
}
const unsigned char *ptr = temp_key->data;
/* we use ephemeral_key for IV */
dcrypt_ctx_sym_set_key(dctx, ptr, 32);
dcrypt_ctx_sym_set_iv(dctx, ptr+32, 16);
safe_memset(buffer_get_modifiable_data(temp_key, 0), 0, temp_key->used);
int ec = 0;
if (!dcrypt_ctx_sym_init(dctx, &error) ||
!dcrypt_ctx_sym_update(dctx, encrypted_key, eklen, key, &error) ||
!dcrypt_ctx_sym_final(dctx, key, &error)) {
io_stream_set_error(&stream->istream.iostream, "Cannot perform key decryption: %s", error);
ec = -1;
}
if (key->used != key_len) {
io_stream_set_error(&stream->istream.iostream, "Cannot perform key decryption: invalid key length");
ec = -1;
}
dcrypt_ctx_sym_destroy(&dctx);
if (ec != 0) return ec;
} else {
io_stream_set_error(&stream->istream.iostream, "Decryption error: unsupported key type 0x%02x", ktype);
return -1;
}
/* make sure we were able to decrypt the encrypted key correctly */
const struct hash_method *hash = hash_method_lookup(t_str_lcase(malg));
if (hash == NULL) {
safe_memset(buffer_get_modifiable_data(key, 0), 0, key->used);
io_stream_set_error(&stream->istream.iostream, "Decryption error: unsupported hash algorithm: %s", malg);
return -1;
}
unsigned char hctx[hash->context_size];
unsigned char hres[hash->digest_size];
hash->init(hctx);
hash->loop(hctx, key->data, key->used);
hash->result(hctx, hres);
for(int i = 1; i < 2049; i++) {
uint32_t i_msb = htonl(i);
hash->init(hctx);
hash->loop(hctx, hres, sizeof(hres));
hash->loop(hctx, &i_msb, sizeof(i_msb));
hash->result(hctx, hres);
}
/* do the comparison */
if (memcmp(ekhash, hres, I_MIN(ekhash_len, sizeof(hres))) != 0) {
safe_memset(buffer_get_modifiable_data(key, 0), 0, key->used);
io_stream_set_error(&stream->istream.iostream, "Decryption error: corrupted header ekhash");
return -1;
}
return 1;
}
static
int o_stream_encrypt_keydata_create_v2(struct encrypt_ostream *stream, const char *malg)
{
const struct hash_method *hash = hash_method_lookup(malg);
const char *error;
size_t tagsize;
const unsigned char *ptr;
size_t kl;
unsigned int val;
buffer_t *keydata, *res;
if (hash == NULL) {
io_stream_set_error(&stream->ostream.iostream,
"Encryption init error: Hash algorithm '%s' not supported", malg);
return -1;
}
/* key data length for internal use */
if ((stream->flags & IO_STREAM_ENC_INTEGRITY_HMAC) == IO_STREAM_ENC_INTEGRITY_HMAC) {
tagsize = IOSTREAM_TAG_SIZE;
} else if ((stream->flags & IO_STREAM_ENC_INTEGRITY_AEAD) == IO_STREAM_ENC_INTEGRITY_AEAD) {
tagsize = IOSTREAM_TAG_SIZE;
} else {
/* do not include MAC */
tagsize = 0;
}
/* generate keydata length of random data for key/iv/mac */
kl = dcrypt_ctx_sym_get_key_length(stream->ctx_sym) + dcrypt_ctx_sym_get_iv_length(stream->ctx_sym) + tagsize;
keydata = buffer_create_dynamic(pool_datastack_create(), kl);
random_fill(buffer_append_space_unsafe(keydata, kl), kl);
buffer_set_used_size(keydata, kl);
ptr = keydata->data;
res = buffer_create_dynamic(default_pool, 256);
/* store number of public key(s) */
buffer_append(res, "\1", 1); /* one key for now */
/* we can do multiple keys at this point, but do it only once now */
if (o_stream_encrypt_key_for_pubkey_v2(stream, malg, ptr, kl, stream->pub, res) != 0) {
buffer_free(&res);
return -1;
}
/* create hash of the key data */
unsigned char hctx[hash->context_size];
unsigned char hres[hash->digest_size];
hash->init(hctx);
hash->loop(hctx, ptr, kl);
hash->result(hctx, hres);
for(int i = 1; i < 2049; i++) {
uint32_t i_msb = htonl(i);
hash->init(hctx);
hash->loop(hctx, hres, sizeof(hres));
hash->loop(hctx, &i_msb, sizeof(i_msb));
hash->result(hctx, hres);
}
/* store key data hash */
val = htonl(sizeof(hres));
buffer_append(res, &val, 4);
buffer_append(res, hres, sizeof(hres));
/* pick up key data that goes into stream */
stream->key_data_len = res->used;
stream->key_data = buffer_free_without_data(&res);
/* prime contexts */
dcrypt_ctx_sym_set_key(stream->ctx_sym, ptr, dcrypt_ctx_sym_get_key_length(stream->ctx_sym));
ptr += dcrypt_ctx_sym_get_key_length(stream->ctx_sym);
dcrypt_ctx_sym_set_iv(stream->ctx_sym, ptr, dcrypt_ctx_sym_get_iv_length(stream->ctx_sym));
ptr += dcrypt_ctx_sym_get_iv_length(stream->ctx_sym);
if ((stream->flags & IO_STREAM_ENC_INTEGRITY_HMAC) == IO_STREAM_ENC_INTEGRITY_HMAC) {
dcrypt_ctx_hmac_set_key(stream->ctx_mac, ptr, tagsize);
dcrypt_ctx_hmac_init(stream->ctx_mac, &error);
} else if ((stream->flags & IO_STREAM_ENC_INTEGRITY_AEAD) == IO_STREAM_ENC_INTEGRITY_AEAD) {
dcrypt_ctx_sym_set_aad(stream->ctx_sym, ptr, tagsize);
}
/* clear out private key data */
safe_memset(buffer_get_modifiable_data(keydata, 0), 0, keydata->used);
if (!dcrypt_ctx_sym_init(stream->ctx_sym, &error)) {
io_stream_set_error(&stream->ostream.iostream, "Encryption init error: %s", error);
return -1;
}
return 0;
}
