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TCRYPT: support keyfiles

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This commit is contained in:
Milan Broz
2012-11-16 14:57:05 +01:00
parent 3cbb43a73a
commit ecf993834c
6 changed files with 108 additions and 34 deletions
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96
lib/tcrypt/tcrypt.c
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@@ -248,24 +248,80 @@ static int decrypt_hdr(struct crypt_device *cd, struct tcrypt_phdr *hdr,
return r;
}
static int pool_keyfile(struct crypt_device *cd,
unsigned char pool[TCRYPT_KEY_POOL_LEN],
const char *keyfile)
{
unsigned char data[TCRYPT_KEYFILE_LEN];
int i, j, fd, data_size;
uint32_t crc;
unsigned char *crc_c = (unsigned char*)&crc;
log_dbg("TCRYPT: using keyfile %s.", keyfile);
fd = open(keyfile, O_RDONLY);
if (fd < 0) {
log_err(cd, _("Failed to open key file.\n"));
return -EIO;
}
/* FIXME: add while */
data_size = read(fd, data, TCRYPT_KEYFILE_LEN);
close(fd);
if (data_size < 0) {
log_err(cd, _("Error reading keyfile %s.\n"), keyfile);
return -EIO;
}
for (i = 0, j = 0, crc = ~0U; i < data_size; i++) {
crc = crypt_crc32(crc, &data[i], 1);
pool[j++] += crc_c[3];
pool[j++] += crc_c[2];
pool[j++] += crc_c[1];
pool[j++] += crc_c[0];
j %= TCRYPT_KEY_POOL_LEN;
}
crc = 0;
memset(data, 0, TCRYPT_KEYFILE_LEN);
return 0;
}
static int TCRYPT_init_hdr(struct crypt_device *cd,
struct tcrypt_phdr *hdr,
struct crypt_params_tcrypt *params,
const char *passphrase,
size_t passphrase_size)
struct crypt_params_tcrypt *params)
{
unsigned char pwd[TCRYPT_KEY_POOL_LEN] = {};
size_t passphrase_size;
char *key;
int r, i;
if (posix_memalign((void*)&key, crypt_getpagesize(), TCRYPT_HDR_KEY_LEN))
return -ENOMEM;
if (params->keyfiles_count)
passphrase_size = TCRYPT_KEY_POOL_LEN;
else
passphrase_size = params->passphrase_size;
/* Calculate pool content from keyfiles */
for (i = 0; i < params->keyfiles_count; i++) {
r = pool_keyfile(cd, pwd, params->keyfiles[i]);
if (r < 0)
goto out;
}
/* If provided password, combine it with pool */
for (i = 0; i < params->passphrase_size; i++)
pwd[i] += params->passphrase[i];
for (i = 0; tcrypt_kdf[i].name; i++) {
/* Derive header key */
log_dbg("TCRYPT: trying KDF: %s-%s-%d.",
tcrypt_kdf[i].name, tcrypt_kdf[i].hash, tcrypt_kdf[i].iterations);
r = crypt_pbkdf(tcrypt_kdf[i].name, tcrypt_kdf[i].hash,
passphrase, passphrase_size,
(char*)pwd, passphrase_size,
hdr->salt, TCRYPT_HDR_SALT_LEN,
key, TCRYPT_HDR_KEY_LEN,
tcrypt_kdf[i].iterations);
@@ -277,25 +333,26 @@ static int TCRYPT_init_hdr(struct crypt_device *cd,
if (r != -EPERM)
break;
}
free(key);
if (r < 0)
return r;
goto out;
r = hdr_from_disk(hdr, params, i, r);
if (r < 0)
return r;
goto out;
hdr_info(cd, hdr, params);
return 0;
out:
memset(pwd, 0, TCRYPT_KEY_POOL_LEN);
if (key)
memset(key, 0, TCRYPT_HDR_KEY_LEN);
free(key);
return r;
}
int TCRYPT_read_phdr(struct crypt_device *cd,
struct tcrypt_phdr *hdr,
struct crypt_params_tcrypt *params,
const char *passphrase,
size_t passphrase_size,
uint32_t flags)
struct crypt_params_tcrypt *params)
{
struct device *device = crypt_metadata_device(cd);
ssize_t hdr_size = sizeof(struct tcrypt_phdr);
@@ -312,19 +369,18 @@ int TCRYPT_read_phdr(struct crypt_device *cd,
return -EINVAL;
}
if ((flags & CRYPT_TCRYPT_HIDDEN_HEADER) &&
if ((params->flags & CRYPT_TCRYPT_HIDDEN_HEADER) &&
lseek(devfd, TCRYPT_HDR_HIDDEN_OFFSET, SEEK_SET) < 0) {
log_err(cd, _("Cannot seek to hidden header for %s.\n"), device_path(device));
r = -EIO;
goto out;
close(devfd);
return -EIO;
}
if (read_blockwise(devfd, device_block_size(device), hdr, hdr_size) == hdr_size) {
params->flags = flags;
r = TCRYPT_init_hdr(cd, hdr, params, passphrase, passphrase_size);
} else
if (read_blockwise(devfd, device_block_size(device), hdr, hdr_size) == hdr_size)
r = TCRYPT_init_hdr(cd, hdr, params);
else
r = -EIO;
out:
close(devfd);
return r;
}