/*
* trusted_read - copy the sealed blob data to userspace in hex.
* On success, return to userspace the trusted key datablob size.
*/
static long trusted_read(const struct key *key, char __user *buffer,
size_t buflen)
{
const struct trusted_key_payload *p;
char *ascii_buf;
char *bufp;
int i;
p = dereference_key_locked(key);
if (!p)
return -EINVAL;
if (buffer && buflen >= 2 * p->blob_len) {
ascii_buf = kmalloc_array(2, p->blob_len, GFP_KERNEL);
if (!ascii_buf)
return -ENOMEM;
bufp = ascii_buf;
for (i = 0; i < p->blob_len; i++)
bufp = hex_byte_pack(bufp, p->blob[i]);
if (copy_to_user(buffer, ascii_buf, 2 * p->blob_len) != 0) {
kzfree(ascii_buf);
return -EFAULT;
}
kzfree(ascii_buf);
}
return 2 * p->blob_len;
}
/*
* encrypted_read - format and copy the encrypted data to userspace
*
* The resulting datablob format is:
* <master-key name> <decrypted data length> <encrypted iv> <encrypted data>
*
* On success, return to userspace the encrypted key datablob size.
*/
static long encrypted_read(const struct key *key, char __user *buffer,
size_t buflen)
{
struct encrypted_key_payload *epayload;
struct key *mkey;
const u8 *master_key;
size_t master_keylen;
char derived_key[HASH_SIZE];
char *ascii_buf;
size_t asciiblob_len;
int ret;
epayload = dereference_key_locked(key);
/* returns the hex encoded iv, encrypted-data, and hmac as ascii */
asciiblob_len = epayload->datablob_len + ivsize + 1
+ roundup(epayload->decrypted_datalen, blksize)
+ (HASH_SIZE * 2);
if (!buffer || buflen < asciiblob_len)
return asciiblob_len;
mkey = request_master_key(epayload, &master_key, &master_keylen);
if (IS_ERR(mkey))
return PTR_ERR(mkey);
ret = get_derived_key(derived_key, ENC_KEY, master_key, master_keylen);
if (ret < 0)
goto out;
ret = derived_key_encrypt(epayload, derived_key, sizeof derived_key);
if (ret < 0)
goto out;
ret = datablob_hmac_append(epayload, master_key, master_keylen);
if (ret < 0)
goto out;
ascii_buf = datablob_format(epayload, asciiblob_len);
if (!ascii_buf) {
ret = -ENOMEM;
goto out;
}
up_read(&mkey->sem);
key_put(mkey);
if (copy_to_user(buffer, ascii_buf, asciiblob_len) != 0)
ret = -EFAULT;
kfree(ascii_buf);
return asciiblob_len;
out:
up_read(&mkey->sem);
key_put(mkey);
return ret;
}
