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First attempts at DesX decryption (not working yet!).

edge.strict_endians
antona 2005-07-22 23:45:32 +00:00
parent 93194b37a0
commit 00c7127551
1 changed files with 77 additions and 42 deletions
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119
ntfsprogs/decrypt.c
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@ -97,6 +97,7 @@ typedef struct {
typedef struct {
unsigned int gcry_algo;
unsigned int gcry_mode;
char *key_data;
gcry_cipher_hd_t gcry_cipher_hd; // handle to the decrypted FEK.
gcry_sexp_t sexp_key; // the user's RSA key.
@ -429,9 +430,39 @@ unsigned int decrypt_decrypt_sector(decrypt_key *key, void *data,
// FIXME: Why are we not calling gcry_cipher_setiv() here instead of
// doing it by hand after the decryption?
if ((gcry_error2 = gcry_cipher_decrypt(dkey->gcry_cipher_hd,
data, 512, NULL, 0))) {
fprintf(stderr, "gcry_error2 is %u.\n", gcry_error2);
if (dkey->gcry_mode == GCRY_CIPHER_MODE_CBC) {
if ((gcry_error2 = gcry_cipher_decrypt(dkey->gcry_cipher_hd,
data, 512, NULL, 0))) {
fprintf(stderr, "gcry_error2 is %u.\n", gcry_error2);
}
} else {
u64 *pos, *end;
u64 k2, k3;
/* DesX is special. */
// FIXME: Need to find out which 8 bytes are the DES key...
pos = data;
end = data + (512/8);
k2 = *(u64*)dkey->key_data;
//k2 = *(u64*)(dkey->key_data + 8);
//k2 = *(u64*)(dkey->key_data + 16);
//k3 = *(u64*)(dkey->key_data);
k3 = *(u64*)(dkey->key_data + 8);
//k3 = *(u64*)(dkey->key_data + 16);
do {
*pos ^= k2;
if ((gcry_error2 = gcry_cipher_decrypt(
dkey->gcry_cipher_hd,
(unsigned char*)pos, 8, NULL, 0))) {
fprintf(stderr, "gcry_error2 is %u.\n",
gcry_error2);
break;
}
*pos ^= k3;
} while (++pos < end);
}
if (dkey->gcry_algo == GCRY_CIPHER_AES256) {
@ -485,7 +516,7 @@ void desx_key_expand(u8 *src, u8* dst) {
}
static decrypt_key *decrypt_make_gcry_key(char *key_data, int gcry_algo) {
int gcry_mode, gcry_length;
int gcry_length;
gcry_error_t gcry_error2;
DECRYPT_KEY *key;
@ -494,33 +525,42 @@ static decrypt_key *decrypt_make_gcry_key(char *key_data, int gcry_algo) {
return NULL;
}
key->key_data = key_data;
switch (gcry_algo) {
case GCRY_CIPHER_DES_SK:
gcry_mode = GCRY_CIPHER_MODE_CBC;
gcry_length = 24;
break;
case GCRY_CIPHER_3DES:
gcry_mode = GCRY_CIPHER_MODE_CBC;
gcry_length = 24;
break;
case GCRY_CIPHER_AES256:
gcry_mode = GCRY_CIPHER_MODE_CBC;
gcry_length = 32;
break;
default:
/* FIXME: This should use standard Des. */
errno = ENOTSUP;
return 0;
case GCRY_CIPHER_DES_SK:
gcry_algo = GCRY_CIPHER_DES;
key->gcry_mode = GCRY_CIPHER_MODE_ECB;
gcry_length = 8;
//key_data += 8;
key_data += 16;
break;
case GCRY_CIPHER_3DES:
key->gcry_mode = GCRY_CIPHER_MODE_CBC;
gcry_length = 24;
break;
case GCRY_CIPHER_AES256:
key->gcry_mode = GCRY_CIPHER_MODE_CBC;
gcry_length = 32;
break;
case GCRY_CIPHER_DES:
key->gcry_mode = GCRY_CIPHER_MODE_CBC;
gcry_length = 8;
break;
default:
errno = ENOTSUP;
return 0;
}
if ((gcry_error2 = gcry_cipher_open(&key->gcry_cipher_hd, gcry_algo,
gcry_mode, 0)) != GPG_ERR_NO_ERROR) {
key->gcry_mode, 0)) != GPG_ERR_NO_ERROR) {
fprintf(stderr, "gcry_error1 is %u.\n", gcry_error2);
errno = -1;
return 0;
}
if ((gcry_error2 = gcry_cipher_setkey(key->gcry_cipher_hd, key_data,
gcry_length))) {
if ((gcry_error2 = gcry_cipher_setkey(key->gcry_cipher_hd,
key_data, gcry_length))) {
fprintf(stderr, "gcry_error2 is %u.\n", gcry_error2);
}
@ -535,30 +575,25 @@ decrypt_key *decrypt_make_key(
void *data) {
unsigned int key_size, alg_id;
char *key_data;
u8 desx_key[192 / 16];
u8 desx_key[192 / 8];
key_size = *((unsigned int *)data);
alg_id = *(((unsigned int *)data) + 2);
key_data = (((char *)data) + 16);
switch (alg_id) {
case CALG_DESX:
desx_key_expand(key_data, desx_key);
//fprintf(stderr, "DESX key of %u bytes\n", key_size);
return decrypt_make_gcry_key(desx_key,
GCRY_CIPHER_DES_SK);
case CALG_3DES:
//fprintf(stderr, "3DES Key of %u bytes\n", key_size);
return decrypt_make_gcry_key(key_data,
GCRY_CIPHER_3DES);
case CALG_AES_256:
//fprintf(stderr, "AES Key of %u bytes\n", key_size);
return decrypt_make_gcry_key(key_data,
GCRY_CIPHER_AES256);
default:
//fprintf(stderr, "DES key of %u bytes\n", key_size);
fprintf(stderr, "DES is not supported yet.\n");
errno = ENOTSUP;
return NULL;
case CALG_DESX:
fprintf(stderr, "DESX key of %u bytes\n", key_size);
desx_key_expand(key_data, desx_key);
return decrypt_make_gcry_key(desx_key, GCRY_CIPHER_DES_SK);
case CALG_3DES:
fprintf(stderr, "3DES Key of %u bytes\n", key_size);
return decrypt_make_gcry_key(key_data, GCRY_CIPHER_3DES);
case CALG_AES_256:
fprintf(stderr, "AES Key of %u bytes\n", key_size);
return decrypt_make_gcry_key(key_data, GCRY_CIPHER_AES256);
default:
fprintf(stderr, "DES key of %u bytes\n", key_size);
return decrypt_make_gcry_key(key_data, GCRY_CIPHER_DES);
}
}