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TCRYPT: parse cipher chain on init.

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This commit is contained in:
Milan Broz
2012-11-22 17:28:03 +01:00
parent 3faaa8b227
commit 0996a43dbb
4 changed files with 119 additions and 26 deletions
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122
lib/tcrypt/tcrypt.c
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@@ -111,17 +111,14 @@ static void hdr_info(struct crypt_device *cd, struct tcrypt_phdr *hdr,
log_dbg("Flags: %d", (int)hdr->d.flags);
log_dbg("MK: offset %d, size %d", (int)hdr->d.mk_offset, (int)hdr->d.mk_size);
log_dbg("KDF: PBKDF2, hash %s", params->hash_name);
log_dbg("Cipher: %s%s%s%s%s-%s",
params->cipher[0],
params->cipher[1] ? "-" : "", params->cipher[1] ?: "",
params->cipher[2] ? "-" : "", params->cipher[2] ?: "",
params->mode);
log_dbg("Cipher: %s-%s", params->cipher, params->mode);
}
static int hdr_from_disk(struct tcrypt_phdr *hdr,
struct crypt_params_tcrypt *params,
int kdf_index, int cipher_index)
{
char cipher_name[MAX_CIPHER_LEN * 4];
uint32_t crc32;
size_t size;
@@ -170,11 +167,26 @@ static int hdr_from_disk(struct tcrypt_phdr *hdr,
params->hash_name = tcrypt_kdf[kdf_index].hash;
params->cipher[0] = tcrypt_cipher[cipher_index].cipher[0].name;
params->cipher[1] = tcrypt_cipher[cipher_index].cipher[1].name;
params->cipher[2] = tcrypt_cipher[cipher_index].cipher[2].name;
params->mode = tcrypt_cipher[cipher_index].mode;
params->key_size = tcrypt_cipher[cipher_index].cipher[0].key_size; //fixme
params->key_size = tcrypt_cipher[cipher_index].cipher[0].key_size;
strncpy(cipher_name, tcrypt_cipher[cipher_index].cipher[0].name,
sizeof(cipher_name));
if (tcrypt_cipher[cipher_index].cipher[1].name) {
strcat(cipher_name, "-");
strncat(cipher_name, tcrypt_cipher[cipher_index].cipher[1].name,
MAX_CIPHER_LEN);
params->key_size += tcrypt_cipher[cipher_index].cipher[1].key_size;
}
if (tcrypt_cipher[cipher_index].cipher[2].name) {
strcat(cipher_name, "-");
strncat(cipher_name, tcrypt_cipher[cipher_index].cipher[2].name,
MAX_CIPHER_LEN);
params->key_size += tcrypt_cipher[cipher_index].cipher[2].key_size;
}
params->cipher = strdup(cipher_name);
params->mode = strdup(tcrypt_cipher[cipher_index].mode);
return 0;
}
@@ -494,12 +506,8 @@ int TCRYPT_activate(struct crypt_device *cd,
{
char cipher[MAX_CIPHER_LEN], dm_name[PATH_MAX], dm_dev_name[PATH_MAX];
struct device *device = NULL;
int i, r;
struct tcrypt_alg tcipher[3] = {
{ params->cipher[0], params->key_size, 0 },
{ params->cipher[1], params->key_size, 0 },
{ params->cipher[2], params->key_size, 0 }
};
int i, r, num_ciphers;
char cname[3][MAX_CIPHER_LEN];
struct crypt_dm_active_device dmd = {
.target = DM_CRYPT,
.size = 0,
@@ -521,13 +529,23 @@ int TCRYPT_activate(struct crypt_device *cd,
if (r)
return r;
dmd.u.crypt.vk = crypt_alloc_volume_key(params->key_size, NULL);
/* Parse cipher chain from c1[-c2[-c3]] */
cname[0][0] = cname[1][0] = cname[2][0] = '\0';
num_ciphers = sscanf(params->cipher, "%" MAX_CIPHER_LEN_STR "[^-]-%"
MAX_CIPHER_LEN_STR "[^-]-%"
MAX_CIPHER_LEN_STR "s",
cname[0], cname[1], cname[2]);
if (num_ciphers < 1)
return -EINVAL;
/* Frome here, key size for every cipher must be the same */
dmd.u.crypt.vk = crypt_alloc_volume_key(params->key_size / num_ciphers, NULL);
if (!dmd.u.crypt.vk)
return -ENOMEM;
for (i = 2; i >= 0; i--) {
if (!params->cipher[i])
if (!cname[i][0])
continue;
if (i == 0) {
@@ -539,12 +557,11 @@ int TCRYPT_activate(struct crypt_device *cd,
}
snprintf(cipher, sizeof(cipher), "%s-%s",
params->cipher[i], params->mode);
copy_key(dmd.u.crypt.vk->key, hdr->d.keys,
top_cipher(tcipher),
params->key_size, i, params->mode);
cname[i], params->mode);
copy_key(dmd.u.crypt.vk->key, hdr->d.keys, num_ciphers - 1,
params->key_size / num_ciphers, i, params->mode);
if (top_cipher(tcipher) != i) {
if ((num_ciphers -1) != i) {
snprintf(dm_dev_name, sizeof(dm_dev_name), "%s/%s_%d",
dm_get_dir(), name, i + 1);
r = device_alloc(&device, dm_dev_name);
@@ -622,3 +639,62 @@ out:
free(CONST_CAST(void*)dmd.uuid);
return (r == -ENODEV) ? 0 : r;
}
static int status_one(struct crypt_device *cd, const char *name,
const char *base_uuid, int index,
size_t *key_size, char *cipher)
{
struct crypt_dm_active_device dmd = {};
char dm_name[PATH_MAX], *c;
int r;
if (snprintf(dm_name, sizeof(dm_name), "%s_%d", name, index) < 0)
return -ENOMEM;
r = dm_status_device(cd, dm_name);
if (r < 0)
return r;
r = dm_query_device(cd, dm_name, DM_ACTIVE_UUID |
DM_ACTIVE_CRYPT_CIPHER |
DM_ACTIVE_CRYPT_KEYSIZE, &dmd);
if (r > 0)
r = 0;
if (!r && !strncmp(dmd.uuid, base_uuid, strlen(base_uuid))) {
if ((c = strchr(dmd.u.crypt.cipher, '-')))
*c = '\0';
strcat(cipher, "-");
strncat(cipher, dmd.u.crypt.cipher, MAX_CIPHER_LEN);
*key_size += dmd.u.crypt.vk->keylength;
} else
r = -ENODEV;
free(CONST_CAST(void*)dmd.uuid);
free(CONST_CAST(void*)dmd.u.crypt.cipher);
crypt_free_volume_key(dmd.u.crypt.vk);
return r;
}
int TCRYPT_init_by_name(struct crypt_device *cd, const char *name,
const struct crypt_dm_active_device *dmd,
struct crypt_params_tcrypt *tcrypt_params,
struct tcrypt_phdr *tcrypt_hdr)
{
char cipher[MAX_CIPHER_LEN * 4], *mode;
memset(tcrypt_params, 0, sizeof(*tcrypt_params));
memset(tcrypt_hdr, 0, sizeof(*tcrypt_hdr));
strncpy(cipher, dmd->u.crypt.cipher, MAX_CIPHER_LEN);
if ((mode = strchr(cipher, '-'))) {
*mode = '\0';
tcrypt_params->mode = strdup(++mode);
}
tcrypt_params->key_size = dmd->u.crypt.vk->keylength;
if (!status_one(cd, name, dmd->uuid, 1, &tcrypt_params->key_size, cipher))
status_one(cd, name, dmd->uuid, 2, &tcrypt_params->key_size, cipher);
tcrypt_params->cipher = strdup(cipher);
return 0;
}