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2531 lines
79 KiB
2531 lines
79 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
|
/* |
|
* eCryptfs: Linux filesystem encryption layer |
|
* In-kernel key management code. Includes functions to parse and |
|
* write authentication token-related packets with the underlying |
|
* file. |
|
* |
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* Copyright (C) 2004-2006 International Business Machines Corp. |
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* Author(s): Michael A. Halcrow <[email protected]> |
|
* Michael C. Thompson <[email protected]> |
|
* Trevor S. Highland <[email protected]> |
|
*/ |
|
|
|
#include <crypto/hash.h> |
|
#include <crypto/skcipher.h> |
|
#include <linux/string.h> |
|
#include <linux/pagemap.h> |
|
#include <linux/key.h> |
|
#include <linux/random.h> |
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#include <linux/scatterlist.h> |
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#include <linux/slab.h> |
|
#include "ecryptfs_kernel.h" |
|
|
|
/* |
|
* request_key returned an error instead of a valid key address; |
|
* determine the type of error, make appropriate log entries, and |
|
* return an error code. |
|
*/ |
|
static int process_request_key_err(long err_code) |
|
{ |
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int rc = 0; |
|
|
|
switch (err_code) { |
|
case -ENOKEY: |
|
ecryptfs_printk(KERN_WARNING, "No key\n"); |
|
rc = -ENOENT; |
|
break; |
|
case -EKEYEXPIRED: |
|
ecryptfs_printk(KERN_WARNING, "Key expired\n"); |
|
rc = -ETIME; |
|
break; |
|
case -EKEYREVOKED: |
|
ecryptfs_printk(KERN_WARNING, "Key revoked\n"); |
|
rc = -EINVAL; |
|
break; |
|
default: |
|
ecryptfs_printk(KERN_WARNING, "Unknown error code: " |
|
"[0x%.16lx]\n", err_code); |
|
rc = -EINVAL; |
|
} |
|
return rc; |
|
} |
|
|
|
static int process_find_global_auth_tok_for_sig_err(int err_code) |
|
{ |
|
int rc = err_code; |
|
|
|
switch (err_code) { |
|
case -ENOENT: |
|
ecryptfs_printk(KERN_WARNING, "Missing auth tok\n"); |
|
break; |
|
case -EINVAL: |
|
ecryptfs_printk(KERN_WARNING, "Invalid auth tok\n"); |
|
break; |
|
default: |
|
rc = process_request_key_err(err_code); |
|
break; |
|
} |
|
return rc; |
|
} |
|
|
|
/** |
|
* ecryptfs_parse_packet_length |
|
* @data: Pointer to memory containing length at offset |
|
* @size: This function writes the decoded size to this memory |
|
* address; zero on error |
|
* @length_size: The number of bytes occupied by the encoded length |
|
* |
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* Returns zero on success; non-zero on error |
|
*/ |
|
int ecryptfs_parse_packet_length(unsigned char *data, size_t *size, |
|
size_t *length_size) |
|
{ |
|
int rc = 0; |
|
|
|
(*length_size) = 0; |
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(*size) = 0; |
|
if (data[0] < 192) { |
|
/* One-byte length */ |
|
(*size) = data[0]; |
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(*length_size) = 1; |
|
} else if (data[0] < 224) { |
|
/* Two-byte length */ |
|
(*size) = (data[0] - 192) * 256; |
|
(*size) += data[1] + 192; |
|
(*length_size) = 2; |
|
} else if (data[0] == 255) { |
|
/* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */ |
|
ecryptfs_printk(KERN_ERR, "Five-byte packet length not " |
|
"supported\n"); |
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rc = -EINVAL; |
|
goto out; |
|
} else { |
|
ecryptfs_printk(KERN_ERR, "Error parsing packet length\n"); |
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rc = -EINVAL; |
|
goto out; |
|
} |
|
out: |
|
return rc; |
|
} |
|
|
|
/** |
|
* ecryptfs_write_packet_length |
|
* @dest: The byte array target into which to write the length. Must |
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* have at least ECRYPTFS_MAX_PKT_LEN_SIZE bytes allocated. |
|
* @size: The length to write. |
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* @packet_size_length: The number of bytes used to encode the packet |
|
* length is written to this address. |
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* |
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* Returns zero on success; non-zero on error. |
|
*/ |
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int ecryptfs_write_packet_length(char *dest, size_t size, |
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size_t *packet_size_length) |
|
{ |
|
int rc = 0; |
|
|
|
if (size < 192) { |
|
dest[0] = size; |
|
(*packet_size_length) = 1; |
|
} else if (size < 65536) { |
|
dest[0] = (((size - 192) / 256) + 192); |
|
dest[1] = ((size - 192) % 256); |
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(*packet_size_length) = 2; |
|
} else { |
|
/* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */ |
|
rc = -EINVAL; |
|
ecryptfs_printk(KERN_WARNING, |
|
"Unsupported packet size: [%zd]\n", size); |
|
} |
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return rc; |
|
} |
|
|
|
static int |
|
write_tag_64_packet(char *signature, struct ecryptfs_session_key *session_key, |
|
char **packet, size_t *packet_len) |
|
{ |
|
size_t i = 0; |
|
size_t data_len; |
|
size_t packet_size_len; |
|
char *message; |
|
int rc; |
|
|
|
/* |
|
* ***** TAG 64 Packet Format ***** |
|
* | Content Type | 1 byte | |
|
* | Key Identifier Size | 1 or 2 bytes | |
|
* | Key Identifier | arbitrary | |
|
* | Encrypted File Encryption Key Size | 1 or 2 bytes | |
|
* | Encrypted File Encryption Key | arbitrary | |
|
*/ |
|
data_len = (5 + ECRYPTFS_SIG_SIZE_HEX |
|
+ session_key->encrypted_key_size); |
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*packet = kmalloc(data_len, GFP_KERNEL); |
|
message = *packet; |
|
if (!message) { |
|
ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n"); |
|
rc = -ENOMEM; |
|
goto out; |
|
} |
|
message[i++] = ECRYPTFS_TAG_64_PACKET_TYPE; |
|
rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX, |
|
&packet_size_len); |
|
if (rc) { |
|
ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet " |
|
"header; cannot generate packet length\n"); |
|
goto out; |
|
} |
|
i += packet_size_len; |
|
memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX); |
|
i += ECRYPTFS_SIG_SIZE_HEX; |
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rc = ecryptfs_write_packet_length(&message[i], |
|
session_key->encrypted_key_size, |
|
&packet_size_len); |
|
if (rc) { |
|
ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet " |
|
"header; cannot generate packet length\n"); |
|
goto out; |
|
} |
|
i += packet_size_len; |
|
memcpy(&message[i], session_key->encrypted_key, |
|
session_key->encrypted_key_size); |
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i += session_key->encrypted_key_size; |
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*packet_len = i; |
|
out: |
|
return rc; |
|
} |
|
|
|
static int |
|
parse_tag_65_packet(struct ecryptfs_session_key *session_key, u8 *cipher_code, |
|
struct ecryptfs_message *msg) |
|
{ |
|
size_t i = 0; |
|
char *data; |
|
size_t data_len; |
|
size_t m_size; |
|
size_t message_len; |
|
u16 checksum = 0; |
|
u16 expected_checksum = 0; |
|
int rc; |
|
|
|
/* |
|
* ***** TAG 65 Packet Format ***** |
|
* | Content Type | 1 byte | |
|
* | Status Indicator | 1 byte | |
|
* | File Encryption Key Size | 1 or 2 bytes | |
|
* | File Encryption Key | arbitrary | |
|
*/ |
|
message_len = msg->data_len; |
|
data = msg->data; |
|
if (message_len < 4) { |
|
rc = -EIO; |
|
goto out; |
|
} |
|
if (data[i++] != ECRYPTFS_TAG_65_PACKET_TYPE) { |
|
ecryptfs_printk(KERN_ERR, "Type should be ECRYPTFS_TAG_65\n"); |
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rc = -EIO; |
|
goto out; |
|
} |
|
if (data[i++]) { |
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ecryptfs_printk(KERN_ERR, "Status indicator has non-zero value " |
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"[%d]\n", data[i-1]); |
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rc = -EIO; |
|
goto out; |
|
} |
|
rc = ecryptfs_parse_packet_length(&data[i], &m_size, &data_len); |
|
if (rc) { |
|
ecryptfs_printk(KERN_WARNING, "Error parsing packet length; " |
|
"rc = [%d]\n", rc); |
|
goto out; |
|
} |
|
i += data_len; |
|
if (message_len < (i + m_size)) { |
|
ecryptfs_printk(KERN_ERR, "The message received from ecryptfsd " |
|
"is shorter than expected\n"); |
|
rc = -EIO; |
|
goto out; |
|
} |
|
if (m_size < 3) { |
|
ecryptfs_printk(KERN_ERR, |
|
"The decrypted key is not long enough to " |
|
"include a cipher code and checksum\n"); |
|
rc = -EIO; |
|
goto out; |
|
} |
|
*cipher_code = data[i++]; |
|
/* The decrypted key includes 1 byte cipher code and 2 byte checksum */ |
|
session_key->decrypted_key_size = m_size - 3; |
|
if (session_key->decrypted_key_size > ECRYPTFS_MAX_KEY_BYTES) { |
|
ecryptfs_printk(KERN_ERR, "key_size [%d] larger than " |
|
"the maximum key size [%d]\n", |
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session_key->decrypted_key_size, |
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ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES); |
|
rc = -EIO; |
|
goto out; |
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} |
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memcpy(session_key->decrypted_key, &data[i], |
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session_key->decrypted_key_size); |
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i += session_key->decrypted_key_size; |
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expected_checksum += (unsigned char)(data[i++]) << 8; |
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expected_checksum += (unsigned char)(data[i++]); |
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for (i = 0; i < session_key->decrypted_key_size; i++) |
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checksum += session_key->decrypted_key[i]; |
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if (expected_checksum != checksum) { |
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ecryptfs_printk(KERN_ERR, "Invalid checksum for file " |
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"encryption key; expected [%x]; calculated " |
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"[%x]\n", expected_checksum, checksum); |
|
rc = -EIO; |
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} |
|
out: |
|
return rc; |
|
} |
|
|
|
|
|
static int |
|
write_tag_66_packet(char *signature, u8 cipher_code, |
|
struct ecryptfs_crypt_stat *crypt_stat, char **packet, |
|
size_t *packet_len) |
|
{ |
|
size_t i = 0; |
|
size_t j; |
|
size_t data_len; |
|
size_t checksum = 0; |
|
size_t packet_size_len; |
|
char *message; |
|
int rc; |
|
|
|
/* |
|
* ***** TAG 66 Packet Format ***** |
|
* | Content Type | 1 byte | |
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* | Key Identifier Size | 1 or 2 bytes | |
|
* | Key Identifier | arbitrary | |
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* | File Encryption Key Size | 1 or 2 bytes | |
|
* | File Encryption Key | arbitrary | |
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*/ |
|
data_len = (5 + ECRYPTFS_SIG_SIZE_HEX + crypt_stat->key_size); |
|
*packet = kmalloc(data_len, GFP_KERNEL); |
|
message = *packet; |
|
if (!message) { |
|
ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n"); |
|
rc = -ENOMEM; |
|
goto out; |
|
} |
|
message[i++] = ECRYPTFS_TAG_66_PACKET_TYPE; |
|
rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX, |
|
&packet_size_len); |
|
if (rc) { |
|
ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet " |
|
"header; cannot generate packet length\n"); |
|
goto out; |
|
} |
|
i += packet_size_len; |
|
memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX); |
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i += ECRYPTFS_SIG_SIZE_HEX; |
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/* The encrypted key includes 1 byte cipher code and 2 byte checksum */ |
|
rc = ecryptfs_write_packet_length(&message[i], crypt_stat->key_size + 3, |
|
&packet_size_len); |
|
if (rc) { |
|
ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet " |
|
"header; cannot generate packet length\n"); |
|
goto out; |
|
} |
|
i += packet_size_len; |
|
message[i++] = cipher_code; |
|
memcpy(&message[i], crypt_stat->key, crypt_stat->key_size); |
|
i += crypt_stat->key_size; |
|
for (j = 0; j < crypt_stat->key_size; j++) |
|
checksum += crypt_stat->key[j]; |
|
message[i++] = (checksum / 256) % 256; |
|
message[i++] = (checksum % 256); |
|
*packet_len = i; |
|
out: |
|
return rc; |
|
} |
|
|
|
static int |
|
parse_tag_67_packet(struct ecryptfs_key_record *key_rec, |
|
struct ecryptfs_message *msg) |
|
{ |
|
size_t i = 0; |
|
char *data; |
|
size_t data_len; |
|
size_t message_len; |
|
int rc; |
|
|
|
/* |
|
* ***** TAG 65 Packet Format ***** |
|
* | Content Type | 1 byte | |
|
* | Status Indicator | 1 byte | |
|
* | Encrypted File Encryption Key Size | 1 or 2 bytes | |
|
* | Encrypted File Encryption Key | arbitrary | |
|
*/ |
|
message_len = msg->data_len; |
|
data = msg->data; |
|
/* verify that everything through the encrypted FEK size is present */ |
|
if (message_len < 4) { |
|
rc = -EIO; |
|
printk(KERN_ERR "%s: message_len is [%zd]; minimum acceptable " |
|
"message length is [%d]\n", __func__, message_len, 4); |
|
goto out; |
|
} |
|
if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) { |
|
rc = -EIO; |
|
printk(KERN_ERR "%s: Type should be ECRYPTFS_TAG_67\n", |
|
__func__); |
|
goto out; |
|
} |
|
if (data[i++]) { |
|
rc = -EIO; |
|
printk(KERN_ERR "%s: Status indicator has non zero " |
|
"value [%d]\n", __func__, data[i-1]); |
|
|
|
goto out; |
|
} |
|
rc = ecryptfs_parse_packet_length(&data[i], &key_rec->enc_key_size, |
|
&data_len); |
|
if (rc) { |
|
ecryptfs_printk(KERN_WARNING, "Error parsing packet length; " |
|
"rc = [%d]\n", rc); |
|
goto out; |
|
} |
|
i += data_len; |
|
if (message_len < (i + key_rec->enc_key_size)) { |
|
rc = -EIO; |
|
printk(KERN_ERR "%s: message_len [%zd]; max len is [%zd]\n", |
|
__func__, message_len, (i + key_rec->enc_key_size)); |
|
goto out; |
|
} |
|
if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { |
|
rc = -EIO; |
|
printk(KERN_ERR "%s: Encrypted key_size [%zd] larger than " |
|
"the maximum key size [%d]\n", __func__, |
|
key_rec->enc_key_size, |
|
ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES); |
|
goto out; |
|
} |
|
memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size); |
|
out: |
|
return rc; |
|
} |
|
|
|
/** |
|
* ecryptfs_verify_version |
|
* @version: The version number to confirm |
|
* |
|
* Returns zero on good version; non-zero otherwise |
|
*/ |
|
static int ecryptfs_verify_version(u16 version) |
|
{ |
|
int rc = 0; |
|
unsigned char major; |
|
unsigned char minor; |
|
|
|
major = ((version >> 8) & 0xFF); |
|
minor = (version & 0xFF); |
|
if (major != ECRYPTFS_VERSION_MAJOR) { |
|
ecryptfs_printk(KERN_ERR, "Major version number mismatch. " |
|
"Expected [%d]; got [%d]\n", |
|
ECRYPTFS_VERSION_MAJOR, major); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
if (minor != ECRYPTFS_VERSION_MINOR) { |
|
ecryptfs_printk(KERN_ERR, "Minor version number mismatch. " |
|
"Expected [%d]; got [%d]\n", |
|
ECRYPTFS_VERSION_MINOR, minor); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
out: |
|
return rc; |
|
} |
|
|
|
/** |
|
* ecryptfs_verify_auth_tok_from_key |
|
* @auth_tok_key: key containing the authentication token |
|
* @auth_tok: authentication token |
|
* |
|
* Returns zero on valid auth tok; -EINVAL if the payload is invalid; or |
|
* -EKEYREVOKED if the key was revoked before we acquired its semaphore. |
|
*/ |
|
static int |
|
ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key, |
|
struct ecryptfs_auth_tok **auth_tok) |
|
{ |
|
int rc = 0; |
|
|
|
(*auth_tok) = ecryptfs_get_key_payload_data(auth_tok_key); |
|
if (IS_ERR(*auth_tok)) { |
|
rc = PTR_ERR(*auth_tok); |
|
*auth_tok = NULL; |
|
goto out; |
|
} |
|
|
|
if (ecryptfs_verify_version((*auth_tok)->version)) { |
|
printk(KERN_ERR "Data structure version mismatch. Userspace " |
|
"tools must match eCryptfs kernel module with major " |
|
"version [%d] and minor version [%d]\n", |
|
ECRYPTFS_VERSION_MAJOR, ECRYPTFS_VERSION_MINOR); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD |
|
&& (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) { |
|
printk(KERN_ERR "Invalid auth_tok structure " |
|
"returned from key query\n"); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
out: |
|
return rc; |
|
} |
|
|
|
static int |
|
ecryptfs_find_global_auth_tok_for_sig( |
|
struct key **auth_tok_key, |
|
struct ecryptfs_auth_tok **auth_tok, |
|
struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig) |
|
{ |
|
struct ecryptfs_global_auth_tok *walker; |
|
int rc = 0; |
|
|
|
(*auth_tok_key) = NULL; |
|
(*auth_tok) = NULL; |
|
mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); |
|
list_for_each_entry(walker, |
|
&mount_crypt_stat->global_auth_tok_list, |
|
mount_crypt_stat_list) { |
|
if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX)) |
|
continue; |
|
|
|
if (walker->flags & ECRYPTFS_AUTH_TOK_INVALID) { |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
|
|
rc = key_validate(walker->global_auth_tok_key); |
|
if (rc) { |
|
if (rc == -EKEYEXPIRED) |
|
goto out; |
|
goto out_invalid_auth_tok; |
|
} |
|
|
|
down_write(&(walker->global_auth_tok_key->sem)); |
|
rc = ecryptfs_verify_auth_tok_from_key( |
|
walker->global_auth_tok_key, auth_tok); |
|
if (rc) |
|
goto out_invalid_auth_tok_unlock; |
|
|
|
(*auth_tok_key) = walker->global_auth_tok_key; |
|
key_get(*auth_tok_key); |
|
goto out; |
|
} |
|
rc = -ENOENT; |
|
goto out; |
|
out_invalid_auth_tok_unlock: |
|
up_write(&(walker->global_auth_tok_key->sem)); |
|
out_invalid_auth_tok: |
|
printk(KERN_WARNING "Invalidating auth tok with sig = [%s]\n", sig); |
|
walker->flags |= ECRYPTFS_AUTH_TOK_INVALID; |
|
key_put(walker->global_auth_tok_key); |
|
walker->global_auth_tok_key = NULL; |
|
out: |
|
mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); |
|
return rc; |
|
} |
|
|
|
/** |
|
* ecryptfs_find_auth_tok_for_sig |
|
* @auth_tok_key: key containing the authentication token |
|
* @auth_tok: Set to the matching auth_tok; NULL if not found |
|
* @mount_crypt_stat: inode crypt_stat crypto context |
|
* @sig: Sig of auth_tok to find |
|
* |
|
* For now, this function simply looks at the registered auth_tok's |
|
* linked off the mount_crypt_stat, so all the auth_toks that can be |
|
* used must be registered at mount time. This function could |
|
* potentially try a lot harder to find auth_tok's (e.g., by calling |
|
* out to ecryptfsd to dynamically retrieve an auth_tok object) so |
|
* that static registration of auth_tok's will no longer be necessary. |
|
* |
|
* Returns zero on no error; non-zero on error |
|
*/ |
|
static int |
|
ecryptfs_find_auth_tok_for_sig( |
|
struct key **auth_tok_key, |
|
struct ecryptfs_auth_tok **auth_tok, |
|
struct ecryptfs_mount_crypt_stat *mount_crypt_stat, |
|
char *sig) |
|
{ |
|
int rc = 0; |
|
|
|
rc = ecryptfs_find_global_auth_tok_for_sig(auth_tok_key, auth_tok, |
|
mount_crypt_stat, sig); |
|
if (rc == -ENOENT) { |
|
/* if the flag ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY is set in the |
|
* mount_crypt_stat structure, we prevent to use auth toks that |
|
* are not inserted through the ecryptfs_add_global_auth_tok |
|
* function. |
|
*/ |
|
if (mount_crypt_stat->flags |
|
& ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY) |
|
return -EINVAL; |
|
|
|
rc = ecryptfs_keyring_auth_tok_for_sig(auth_tok_key, auth_tok, |
|
sig); |
|
} |
|
return rc; |
|
} |
|
|
|
/* |
|
* write_tag_70_packet can gobble a lot of stack space. We stuff most |
|
* of the function's parameters in a kmalloc'd struct to help reduce |
|
* eCryptfs' overall stack usage. |
|
*/ |
|
struct ecryptfs_write_tag_70_packet_silly_stack { |
|
u8 cipher_code; |
|
size_t max_packet_size; |
|
size_t packet_size_len; |
|
size_t block_aligned_filename_size; |
|
size_t block_size; |
|
size_t i; |
|
size_t j; |
|
size_t num_rand_bytes; |
|
struct mutex *tfm_mutex; |
|
char *block_aligned_filename; |
|
struct ecryptfs_auth_tok *auth_tok; |
|
struct scatterlist src_sg[2]; |
|
struct scatterlist dst_sg[2]; |
|
struct crypto_skcipher *skcipher_tfm; |
|
struct skcipher_request *skcipher_req; |
|
char iv[ECRYPTFS_MAX_IV_BYTES]; |
|
char hash[ECRYPTFS_TAG_70_DIGEST_SIZE]; |
|
char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE]; |
|
struct crypto_shash *hash_tfm; |
|
struct shash_desc *hash_desc; |
|
}; |
|
|
|
/* |
|
* write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK |
|
* @filename: NULL-terminated filename string |
|
* |
|
* This is the simplest mechanism for achieving filename encryption in |
|
* eCryptfs. It encrypts the given filename with the mount-wide |
|
* filename encryption key (FNEK) and stores it in a packet to @dest, |
|
* which the callee will encode and write directly into the dentry |
|
* name. |
|
*/ |
|
int |
|
ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes, |
|
size_t *packet_size, |
|
struct ecryptfs_mount_crypt_stat *mount_crypt_stat, |
|
char *filename, size_t filename_size) |
|
{ |
|
struct ecryptfs_write_tag_70_packet_silly_stack *s; |
|
struct key *auth_tok_key = NULL; |
|
int rc = 0; |
|
|
|
s = kzalloc(sizeof(*s), GFP_KERNEL); |
|
if (!s) |
|
return -ENOMEM; |
|
|
|
(*packet_size) = 0; |
|
rc = ecryptfs_find_auth_tok_for_sig( |
|
&auth_tok_key, |
|
&s->auth_tok, mount_crypt_stat, |
|
mount_crypt_stat->global_default_fnek_sig); |
|
if (rc) { |
|
printk(KERN_ERR "%s: Error attempting to find auth tok for " |
|
"fnek sig [%s]; rc = [%d]\n", __func__, |
|
mount_crypt_stat->global_default_fnek_sig, rc); |
|
goto out; |
|
} |
|
rc = ecryptfs_get_tfm_and_mutex_for_cipher_name( |
|
&s->skcipher_tfm, |
|
&s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name); |
|
if (unlikely(rc)) { |
|
printk(KERN_ERR "Internal error whilst attempting to get " |
|
"tfm and mutex for cipher name [%s]; rc = [%d]\n", |
|
mount_crypt_stat->global_default_fn_cipher_name, rc); |
|
goto out; |
|
} |
|
mutex_lock(s->tfm_mutex); |
|
s->block_size = crypto_skcipher_blocksize(s->skcipher_tfm); |
|
/* Plus one for the \0 separator between the random prefix |
|
* and the plaintext filename */ |
|
s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1); |
|
s->block_aligned_filename_size = (s->num_rand_bytes + filename_size); |
|
if ((s->block_aligned_filename_size % s->block_size) != 0) { |
|
s->num_rand_bytes += (s->block_size |
|
- (s->block_aligned_filename_size |
|
% s->block_size)); |
|
s->block_aligned_filename_size = (s->num_rand_bytes |
|
+ filename_size); |
|
} |
|
/* Octet 0: Tag 70 identifier |
|
* Octets 1-N1: Tag 70 packet size (includes cipher identifier |
|
* and block-aligned encrypted filename size) |
|
* Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE) |
|
* Octet N2-N3: Cipher identifier (1 octet) |
|
* Octets N3-N4: Block-aligned encrypted filename |
|
* - Consists of a minimum number of random characters, a \0 |
|
* separator, and then the filename */ |
|
s->max_packet_size = (ECRYPTFS_TAG_70_MAX_METADATA_SIZE |
|
+ s->block_aligned_filename_size); |
|
if (!dest) { |
|
(*packet_size) = s->max_packet_size; |
|
goto out_unlock; |
|
} |
|
if (s->max_packet_size > (*remaining_bytes)) { |
|
printk(KERN_WARNING "%s: Require [%zd] bytes to write; only " |
|
"[%zd] available\n", __func__, s->max_packet_size, |
|
(*remaining_bytes)); |
|
rc = -EINVAL; |
|
goto out_unlock; |
|
} |
|
|
|
s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL); |
|
if (!s->skcipher_req) { |
|
printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " |
|
"skcipher_request_alloc for %s\n", __func__, |
|
crypto_skcipher_driver_name(s->skcipher_tfm)); |
|
rc = -ENOMEM; |
|
goto out_unlock; |
|
} |
|
|
|
skcipher_request_set_callback(s->skcipher_req, |
|
CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL); |
|
|
|
s->block_aligned_filename = kzalloc(s->block_aligned_filename_size, |
|
GFP_KERNEL); |
|
if (!s->block_aligned_filename) { |
|
rc = -ENOMEM; |
|
goto out_unlock; |
|
} |
|
dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE; |
|
rc = ecryptfs_write_packet_length(&dest[s->i], |
|
(ECRYPTFS_SIG_SIZE |
|
+ 1 /* Cipher code */ |
|
+ s->block_aligned_filename_size), |
|
&s->packet_size_len); |
|
if (rc) { |
|
printk(KERN_ERR "%s: Error generating tag 70 packet " |
|
"header; cannot generate packet length; rc = [%d]\n", |
|
__func__, rc); |
|
goto out_free_unlock; |
|
} |
|
s->i += s->packet_size_len; |
|
ecryptfs_from_hex(&dest[s->i], |
|
mount_crypt_stat->global_default_fnek_sig, |
|
ECRYPTFS_SIG_SIZE); |
|
s->i += ECRYPTFS_SIG_SIZE; |
|
s->cipher_code = ecryptfs_code_for_cipher_string( |
|
mount_crypt_stat->global_default_fn_cipher_name, |
|
mount_crypt_stat->global_default_fn_cipher_key_bytes); |
|
if (s->cipher_code == 0) { |
|
printk(KERN_WARNING "%s: Unable to generate code for " |
|
"cipher [%s] with key bytes [%zd]\n", __func__, |
|
mount_crypt_stat->global_default_fn_cipher_name, |
|
mount_crypt_stat->global_default_fn_cipher_key_bytes); |
|
rc = -EINVAL; |
|
goto out_free_unlock; |
|
} |
|
dest[s->i++] = s->cipher_code; |
|
/* TODO: Support other key modules than passphrase for |
|
* filename encryption */ |
|
if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) { |
|
rc = -EOPNOTSUPP; |
|
printk(KERN_INFO "%s: Filename encryption only supports " |
|
"password tokens\n", __func__); |
|
goto out_free_unlock; |
|
} |
|
s->hash_tfm = crypto_alloc_shash(ECRYPTFS_TAG_70_DIGEST, 0, 0); |
|
if (IS_ERR(s->hash_tfm)) { |
|
rc = PTR_ERR(s->hash_tfm); |
|
printk(KERN_ERR "%s: Error attempting to " |
|
"allocate hash crypto context; rc = [%d]\n", |
|
__func__, rc); |
|
goto out_free_unlock; |
|
} |
|
|
|
s->hash_desc = kmalloc(sizeof(*s->hash_desc) + |
|
crypto_shash_descsize(s->hash_tfm), GFP_KERNEL); |
|
if (!s->hash_desc) { |
|
rc = -ENOMEM; |
|
goto out_release_free_unlock; |
|
} |
|
|
|
s->hash_desc->tfm = s->hash_tfm; |
|
|
|
rc = crypto_shash_digest(s->hash_desc, |
|
(u8 *)s->auth_tok->token.password.session_key_encryption_key, |
|
s->auth_tok->token.password.session_key_encryption_key_bytes, |
|
s->hash); |
|
if (rc) { |
|
printk(KERN_ERR |
|
"%s: Error computing crypto hash; rc = [%d]\n", |
|
__func__, rc); |
|
goto out_release_free_unlock; |
|
} |
|
for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) { |
|
s->block_aligned_filename[s->j] = |
|
s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)]; |
|
if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE) |
|
== (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) { |
|
rc = crypto_shash_digest(s->hash_desc, (u8 *)s->hash, |
|
ECRYPTFS_TAG_70_DIGEST_SIZE, |
|
s->tmp_hash); |
|
if (rc) { |
|
printk(KERN_ERR |
|
"%s: Error computing crypto hash; " |
|
"rc = [%d]\n", __func__, rc); |
|
goto out_release_free_unlock; |
|
} |
|
memcpy(s->hash, s->tmp_hash, |
|
ECRYPTFS_TAG_70_DIGEST_SIZE); |
|
} |
|
if (s->block_aligned_filename[s->j] == '\0') |
|
s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL; |
|
} |
|
memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename, |
|
filename_size); |
|
rc = virt_to_scatterlist(s->block_aligned_filename, |
|
s->block_aligned_filename_size, s->src_sg, 2); |
|
if (rc < 1) { |
|
printk(KERN_ERR "%s: Internal error whilst attempting to " |
|
"convert filename memory to scatterlist; rc = [%d]. " |
|
"block_aligned_filename_size = [%zd]\n", __func__, rc, |
|
s->block_aligned_filename_size); |
|
goto out_release_free_unlock; |
|
} |
|
rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size, |
|
s->dst_sg, 2); |
|
if (rc < 1) { |
|
printk(KERN_ERR "%s: Internal error whilst attempting to " |
|
"convert encrypted filename memory to scatterlist; " |
|
"rc = [%d]. block_aligned_filename_size = [%zd]\n", |
|
__func__, rc, s->block_aligned_filename_size); |
|
goto out_release_free_unlock; |
|
} |
|
/* The characters in the first block effectively do the job |
|
* of the IV here, so we just use 0's for the IV. Note the |
|
* constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES |
|
* >= ECRYPTFS_MAX_IV_BYTES. */ |
|
rc = crypto_skcipher_setkey( |
|
s->skcipher_tfm, |
|
s->auth_tok->token.password.session_key_encryption_key, |
|
mount_crypt_stat->global_default_fn_cipher_key_bytes); |
|
if (rc < 0) { |
|
printk(KERN_ERR "%s: Error setting key for crypto context; " |
|
"rc = [%d]. s->auth_tok->token.password.session_key_" |
|
"encryption_key = [0x%p]; mount_crypt_stat->" |
|
"global_default_fn_cipher_key_bytes = [%zd]\n", __func__, |
|
rc, |
|
s->auth_tok->token.password.session_key_encryption_key, |
|
mount_crypt_stat->global_default_fn_cipher_key_bytes); |
|
goto out_release_free_unlock; |
|
} |
|
skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg, |
|
s->block_aligned_filename_size, s->iv); |
|
rc = crypto_skcipher_encrypt(s->skcipher_req); |
|
if (rc) { |
|
printk(KERN_ERR "%s: Error attempting to encrypt filename; " |
|
"rc = [%d]\n", __func__, rc); |
|
goto out_release_free_unlock; |
|
} |
|
s->i += s->block_aligned_filename_size; |
|
(*packet_size) = s->i; |
|
(*remaining_bytes) -= (*packet_size); |
|
out_release_free_unlock: |
|
crypto_free_shash(s->hash_tfm); |
|
out_free_unlock: |
|
kfree_sensitive(s->block_aligned_filename); |
|
out_unlock: |
|
mutex_unlock(s->tfm_mutex); |
|
out: |
|
if (auth_tok_key) { |
|
up_write(&(auth_tok_key->sem)); |
|
key_put(auth_tok_key); |
|
} |
|
skcipher_request_free(s->skcipher_req); |
|
kfree_sensitive(s->hash_desc); |
|
kfree(s); |
|
return rc; |
|
} |
|
|
|
struct ecryptfs_parse_tag_70_packet_silly_stack { |
|
u8 cipher_code; |
|
size_t max_packet_size; |
|
size_t packet_size_len; |
|
size_t parsed_tag_70_packet_size; |
|
size_t block_aligned_filename_size; |
|
size_t block_size; |
|
size_t i; |
|
struct mutex *tfm_mutex; |
|
char *decrypted_filename; |
|
struct ecryptfs_auth_tok *auth_tok; |
|
struct scatterlist src_sg[2]; |
|
struct scatterlist dst_sg[2]; |
|
struct crypto_skcipher *skcipher_tfm; |
|
struct skcipher_request *skcipher_req; |
|
char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1]; |
|
char iv[ECRYPTFS_MAX_IV_BYTES]; |
|
char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1]; |
|
}; |
|
|
|
/** |
|
* ecryptfs_parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet |
|
* @filename: This function kmalloc's the memory for the filename |
|
* @filename_size: This function sets this to the amount of memory |
|
* kmalloc'd for the filename |
|
* @packet_size: This function sets this to the the number of octets |
|
* in the packet parsed |
|
* @mount_crypt_stat: The mount-wide cryptographic context |
|
* @data: The memory location containing the start of the tag 70 |
|
* packet |
|
* @max_packet_size: The maximum legal size of the packet to be parsed |
|
* from @data |
|
* |
|
* Returns zero on success; non-zero otherwise |
|
*/ |
|
int |
|
ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size, |
|
size_t *packet_size, |
|
struct ecryptfs_mount_crypt_stat *mount_crypt_stat, |
|
char *data, size_t max_packet_size) |
|
{ |
|
struct ecryptfs_parse_tag_70_packet_silly_stack *s; |
|
struct key *auth_tok_key = NULL; |
|
int rc = 0; |
|
|
|
(*packet_size) = 0; |
|
(*filename_size) = 0; |
|
(*filename) = NULL; |
|
s = kzalloc(sizeof(*s), GFP_KERNEL); |
|
if (!s) |
|
return -ENOMEM; |
|
|
|
if (max_packet_size < ECRYPTFS_TAG_70_MIN_METADATA_SIZE) { |
|
printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be " |
|
"at least [%d]\n", __func__, max_packet_size, |
|
ECRYPTFS_TAG_70_MIN_METADATA_SIZE); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
/* Octet 0: Tag 70 identifier |
|
* Octets 1-N1: Tag 70 packet size (includes cipher identifier |
|
* and block-aligned encrypted filename size) |
|
* Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE) |
|
* Octet N2-N3: Cipher identifier (1 octet) |
|
* Octets N3-N4: Block-aligned encrypted filename |
|
* - Consists of a minimum number of random numbers, a \0 |
|
* separator, and then the filename */ |
|
if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) { |
|
printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be " |
|
"tag [0x%.2x]\n", __func__, |
|
data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
rc = ecryptfs_parse_packet_length(&data[(*packet_size)], |
|
&s->parsed_tag_70_packet_size, |
|
&s->packet_size_len); |
|
if (rc) { |
|
printk(KERN_WARNING "%s: Error parsing packet length; " |
|
"rc = [%d]\n", __func__, rc); |
|
goto out; |
|
} |
|
s->block_aligned_filename_size = (s->parsed_tag_70_packet_size |
|
- ECRYPTFS_SIG_SIZE - 1); |
|
if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size) |
|
> max_packet_size) { |
|
printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet " |
|
"size is [%zd]\n", __func__, max_packet_size, |
|
(1 + s->packet_size_len + 1 |
|
+ s->block_aligned_filename_size)); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
(*packet_size) += s->packet_size_len; |
|
ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)], |
|
ECRYPTFS_SIG_SIZE); |
|
s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0'; |
|
(*packet_size) += ECRYPTFS_SIG_SIZE; |
|
s->cipher_code = data[(*packet_size)++]; |
|
rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code); |
|
if (rc) { |
|
printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n", |
|
__func__, s->cipher_code); |
|
goto out; |
|
} |
|
rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key, |
|
&s->auth_tok, mount_crypt_stat, |
|
s->fnek_sig_hex); |
|
if (rc) { |
|
printk(KERN_ERR "%s: Error attempting to find auth tok for " |
|
"fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex, |
|
rc); |
|
goto out; |
|
} |
|
rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->skcipher_tfm, |
|
&s->tfm_mutex, |
|
s->cipher_string); |
|
if (unlikely(rc)) { |
|
printk(KERN_ERR "Internal error whilst attempting to get " |
|
"tfm and mutex for cipher name [%s]; rc = [%d]\n", |
|
s->cipher_string, rc); |
|
goto out; |
|
} |
|
mutex_lock(s->tfm_mutex); |
|
rc = virt_to_scatterlist(&data[(*packet_size)], |
|
s->block_aligned_filename_size, s->src_sg, 2); |
|
if (rc < 1) { |
|
printk(KERN_ERR "%s: Internal error whilst attempting to " |
|
"convert encrypted filename memory to scatterlist; " |
|
"rc = [%d]. block_aligned_filename_size = [%zd]\n", |
|
__func__, rc, s->block_aligned_filename_size); |
|
goto out_unlock; |
|
} |
|
(*packet_size) += s->block_aligned_filename_size; |
|
s->decrypted_filename = kmalloc(s->block_aligned_filename_size, |
|
GFP_KERNEL); |
|
if (!s->decrypted_filename) { |
|
rc = -ENOMEM; |
|
goto out_unlock; |
|
} |
|
rc = virt_to_scatterlist(s->decrypted_filename, |
|
s->block_aligned_filename_size, s->dst_sg, 2); |
|
if (rc < 1) { |
|
printk(KERN_ERR "%s: Internal error whilst attempting to " |
|
"convert decrypted filename memory to scatterlist; " |
|
"rc = [%d]. block_aligned_filename_size = [%zd]\n", |
|
__func__, rc, s->block_aligned_filename_size); |
|
goto out_free_unlock; |
|
} |
|
|
|
s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL); |
|
if (!s->skcipher_req) { |
|
printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " |
|
"skcipher_request_alloc for %s\n", __func__, |
|
crypto_skcipher_driver_name(s->skcipher_tfm)); |
|
rc = -ENOMEM; |
|
goto out_free_unlock; |
|
} |
|
|
|
skcipher_request_set_callback(s->skcipher_req, |
|
CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL); |
|
|
|
/* The characters in the first block effectively do the job of |
|
* the IV here, so we just use 0's for the IV. Note the |
|
* constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES |
|
* >= ECRYPTFS_MAX_IV_BYTES. */ |
|
/* TODO: Support other key modules than passphrase for |
|
* filename encryption */ |
|
if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) { |
|
rc = -EOPNOTSUPP; |
|
printk(KERN_INFO "%s: Filename encryption only supports " |
|
"password tokens\n", __func__); |
|
goto out_free_unlock; |
|
} |
|
rc = crypto_skcipher_setkey( |
|
s->skcipher_tfm, |
|
s->auth_tok->token.password.session_key_encryption_key, |
|
mount_crypt_stat->global_default_fn_cipher_key_bytes); |
|
if (rc < 0) { |
|
printk(KERN_ERR "%s: Error setting key for crypto context; " |
|
"rc = [%d]. s->auth_tok->token.password.session_key_" |
|
"encryption_key = [0x%p]; mount_crypt_stat->" |
|
"global_default_fn_cipher_key_bytes = [%zd]\n", __func__, |
|
rc, |
|
s->auth_tok->token.password.session_key_encryption_key, |
|
mount_crypt_stat->global_default_fn_cipher_key_bytes); |
|
goto out_free_unlock; |
|
} |
|
skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg, |
|
s->block_aligned_filename_size, s->iv); |
|
rc = crypto_skcipher_decrypt(s->skcipher_req); |
|
if (rc) { |
|
printk(KERN_ERR "%s: Error attempting to decrypt filename; " |
|
"rc = [%d]\n", __func__, rc); |
|
goto out_free_unlock; |
|
} |
|
|
|
while (s->i < s->block_aligned_filename_size && |
|
s->decrypted_filename[s->i] != '\0') |
|
s->i++; |
|
if (s->i == s->block_aligned_filename_size) { |
|
printk(KERN_WARNING "%s: Invalid tag 70 packet; could not " |
|
"find valid separator between random characters and " |
|
"the filename\n", __func__); |
|
rc = -EINVAL; |
|
goto out_free_unlock; |
|
} |
|
s->i++; |
|
(*filename_size) = (s->block_aligned_filename_size - s->i); |
|
if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) { |
|
printk(KERN_WARNING "%s: Filename size is [%zd], which is " |
|
"invalid\n", __func__, (*filename_size)); |
|
rc = -EINVAL; |
|
goto out_free_unlock; |
|
} |
|
(*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL); |
|
if (!(*filename)) { |
|
rc = -ENOMEM; |
|
goto out_free_unlock; |
|
} |
|
memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size)); |
|
(*filename)[(*filename_size)] = '\0'; |
|
out_free_unlock: |
|
kfree(s->decrypted_filename); |
|
out_unlock: |
|
mutex_unlock(s->tfm_mutex); |
|
out: |
|
if (rc) { |
|
(*packet_size) = 0; |
|
(*filename_size) = 0; |
|
(*filename) = NULL; |
|
} |
|
if (auth_tok_key) { |
|
up_write(&(auth_tok_key->sem)); |
|
key_put(auth_tok_key); |
|
} |
|
skcipher_request_free(s->skcipher_req); |
|
kfree(s); |
|
return rc; |
|
} |
|
|
|
static int |
|
ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok) |
|
{ |
|
int rc = 0; |
|
|
|
(*sig) = NULL; |
|
switch (auth_tok->token_type) { |
|
case ECRYPTFS_PASSWORD: |
|
(*sig) = auth_tok->token.password.signature; |
|
break; |
|
case ECRYPTFS_PRIVATE_KEY: |
|
(*sig) = auth_tok->token.private_key.signature; |
|
break; |
|
default: |
|
printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n", |
|
auth_tok->token_type); |
|
rc = -EINVAL; |
|
} |
|
return rc; |
|
} |
|
|
|
/** |
|
* decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok. |
|
* @auth_tok: The key authentication token used to decrypt the session key |
|
* @crypt_stat: The cryptographic context |
|
* |
|
* Returns zero on success; non-zero error otherwise. |
|
*/ |
|
static int |
|
decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok, |
|
struct ecryptfs_crypt_stat *crypt_stat) |
|
{ |
|
u8 cipher_code = 0; |
|
struct ecryptfs_msg_ctx *msg_ctx; |
|
struct ecryptfs_message *msg = NULL; |
|
char *auth_tok_sig; |
|
char *payload = NULL; |
|
size_t payload_len = 0; |
|
int rc; |
|
|
|
rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok); |
|
if (rc) { |
|
printk(KERN_ERR "Unrecognized auth tok type: [%d]\n", |
|
auth_tok->token_type); |
|
goto out; |
|
} |
|
rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key), |
|
&payload, &payload_len); |
|
if (rc) { |
|
ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n"); |
|
goto out; |
|
} |
|
rc = ecryptfs_send_message(payload, payload_len, &msg_ctx); |
|
if (rc) { |
|
ecryptfs_printk(KERN_ERR, "Error sending message to " |
|
"ecryptfsd: %d\n", rc); |
|
goto out; |
|
} |
|
rc = ecryptfs_wait_for_response(msg_ctx, &msg); |
|
if (rc) { |
|
ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet " |
|
"from the user space daemon\n"); |
|
rc = -EIO; |
|
goto out; |
|
} |
|
rc = parse_tag_65_packet(&(auth_tok->session_key), |
|
&cipher_code, msg); |
|
if (rc) { |
|
printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n", |
|
rc); |
|
goto out; |
|
} |
|
auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY; |
|
memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key, |
|
auth_tok->session_key.decrypted_key_size); |
|
crypt_stat->key_size = auth_tok->session_key.decrypted_key_size; |
|
rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code); |
|
if (rc) { |
|
ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n", |
|
cipher_code); |
|
goto out; |
|
} |
|
crypt_stat->flags |= ECRYPTFS_KEY_VALID; |
|
if (ecryptfs_verbosity > 0) { |
|
ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n"); |
|
ecryptfs_dump_hex(crypt_stat->key, |
|
crypt_stat->key_size); |
|
} |
|
out: |
|
kfree(msg); |
|
kfree(payload); |
|
return rc; |
|
} |
|
|
|
static void wipe_auth_tok_list(struct list_head *auth_tok_list_head) |
|
{ |
|
struct ecryptfs_auth_tok_list_item *auth_tok_list_item; |
|
struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp; |
|
|
|
list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp, |
|
auth_tok_list_head, list) { |
|
list_del(&auth_tok_list_item->list); |
|
kmem_cache_free(ecryptfs_auth_tok_list_item_cache, |
|
auth_tok_list_item); |
|
} |
|
} |
|
|
|
struct kmem_cache *ecryptfs_auth_tok_list_item_cache; |
|
|
|
/** |
|
* parse_tag_1_packet |
|
* @crypt_stat: The cryptographic context to modify based on packet contents |
|
* @data: The raw bytes of the packet. |
|
* @auth_tok_list: eCryptfs parses packets into authentication tokens; |
|
* a new authentication token will be placed at the |
|
* end of this list for this packet. |
|
* @new_auth_tok: Pointer to a pointer to memory that this function |
|
* allocates; sets the memory address of the pointer to |
|
* NULL on error. This object is added to the |
|
* auth_tok_list. |
|
* @packet_size: This function writes the size of the parsed packet |
|
* into this memory location; zero on error. |
|
* @max_packet_size: The maximum allowable packet size |
|
* |
|
* Returns zero on success; non-zero on error. |
|
*/ |
|
static int |
|
parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat, |
|
unsigned char *data, struct list_head *auth_tok_list, |
|
struct ecryptfs_auth_tok **new_auth_tok, |
|
size_t *packet_size, size_t max_packet_size) |
|
{ |
|
size_t body_size; |
|
struct ecryptfs_auth_tok_list_item *auth_tok_list_item; |
|
size_t length_size; |
|
int rc = 0; |
|
|
|
(*packet_size) = 0; |
|
(*new_auth_tok) = NULL; |
|
/** |
|
* This format is inspired by OpenPGP; see RFC 2440 |
|
* packet tag 1 |
|
* |
|
* Tag 1 identifier (1 byte) |
|
* Max Tag 1 packet size (max 3 bytes) |
|
* Version (1 byte) |
|
* Key identifier (8 bytes; ECRYPTFS_SIG_SIZE) |
|
* Cipher identifier (1 byte) |
|
* Encrypted key size (arbitrary) |
|
* |
|
* 12 bytes minimum packet size |
|
*/ |
|
if (unlikely(max_packet_size < 12)) { |
|
printk(KERN_ERR "Invalid max packet size; must be >=12\n"); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) { |
|
printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n", |
|
ECRYPTFS_TAG_1_PACKET_TYPE); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
/* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or |
|
* at end of function upon failure */ |
|
auth_tok_list_item = |
|
kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, |
|
GFP_KERNEL); |
|
if (!auth_tok_list_item) { |
|
printk(KERN_ERR "Unable to allocate memory\n"); |
|
rc = -ENOMEM; |
|
goto out; |
|
} |
|
(*new_auth_tok) = &auth_tok_list_item->auth_tok; |
|
rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, |
|
&length_size); |
|
if (rc) { |
|
printk(KERN_WARNING "Error parsing packet length; " |
|
"rc = [%d]\n", rc); |
|
goto out_free; |
|
} |
|
if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) { |
|
printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); |
|
rc = -EINVAL; |
|
goto out_free; |
|
} |
|
(*packet_size) += length_size; |
|
if (unlikely((*packet_size) + body_size > max_packet_size)) { |
|
printk(KERN_WARNING "Packet size exceeds max\n"); |
|
rc = -EINVAL; |
|
goto out_free; |
|
} |
|
if (unlikely(data[(*packet_size)++] != 0x03)) { |
|
printk(KERN_WARNING "Unknown version number [%d]\n", |
|
data[(*packet_size) - 1]); |
|
rc = -EINVAL; |
|
goto out_free; |
|
} |
|
ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature, |
|
&data[(*packet_size)], ECRYPTFS_SIG_SIZE); |
|
*packet_size += ECRYPTFS_SIG_SIZE; |
|
/* This byte is skipped because the kernel does not need to |
|
* know which public key encryption algorithm was used */ |
|
(*packet_size)++; |
|
(*new_auth_tok)->session_key.encrypted_key_size = |
|
body_size - (ECRYPTFS_SIG_SIZE + 2); |
|
if ((*new_auth_tok)->session_key.encrypted_key_size |
|
> ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { |
|
printk(KERN_WARNING "Tag 1 packet contains key larger " |
|
"than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n"); |
|
rc = -EINVAL; |
|
goto out_free; |
|
} |
|
memcpy((*new_auth_tok)->session_key.encrypted_key, |
|
&data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2))); |
|
(*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size; |
|
(*new_auth_tok)->session_key.flags &= |
|
~ECRYPTFS_CONTAINS_DECRYPTED_KEY; |
|
(*new_auth_tok)->session_key.flags |= |
|
ECRYPTFS_CONTAINS_ENCRYPTED_KEY; |
|
(*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY; |
|
(*new_auth_tok)->flags = 0; |
|
(*new_auth_tok)->session_key.flags &= |
|
~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT); |
|
(*new_auth_tok)->session_key.flags &= |
|
~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT); |
|
list_add(&auth_tok_list_item->list, auth_tok_list); |
|
goto out; |
|
out_free: |
|
(*new_auth_tok) = NULL; |
|
memset(auth_tok_list_item, 0, |
|
sizeof(struct ecryptfs_auth_tok_list_item)); |
|
kmem_cache_free(ecryptfs_auth_tok_list_item_cache, |
|
auth_tok_list_item); |
|
out: |
|
if (rc) |
|
(*packet_size) = 0; |
|
return rc; |
|
} |
|
|
|
/** |
|
* parse_tag_3_packet |
|
* @crypt_stat: The cryptographic context to modify based on packet |
|
* contents. |
|
* @data: The raw bytes of the packet. |
|
* @auth_tok_list: eCryptfs parses packets into authentication tokens; |
|
* a new authentication token will be placed at the end |
|
* of this list for this packet. |
|
* @new_auth_tok: Pointer to a pointer to memory that this function |
|
* allocates; sets the memory address of the pointer to |
|
* NULL on error. This object is added to the |
|
* auth_tok_list. |
|
* @packet_size: This function writes the size of the parsed packet |
|
* into this memory location; zero on error. |
|
* @max_packet_size: maximum number of bytes to parse |
|
* |
|
* Returns zero on success; non-zero on error. |
|
*/ |
|
static int |
|
parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat, |
|
unsigned char *data, struct list_head *auth_tok_list, |
|
struct ecryptfs_auth_tok **new_auth_tok, |
|
size_t *packet_size, size_t max_packet_size) |
|
{ |
|
size_t body_size; |
|
struct ecryptfs_auth_tok_list_item *auth_tok_list_item; |
|
size_t length_size; |
|
int rc = 0; |
|
|
|
(*packet_size) = 0; |
|
(*new_auth_tok) = NULL; |
|
/** |
|
*This format is inspired by OpenPGP; see RFC 2440 |
|
* packet tag 3 |
|
* |
|
* Tag 3 identifier (1 byte) |
|
* Max Tag 3 packet size (max 3 bytes) |
|
* Version (1 byte) |
|
* Cipher code (1 byte) |
|
* S2K specifier (1 byte) |
|
* Hash identifier (1 byte) |
|
* Salt (ECRYPTFS_SALT_SIZE) |
|
* Hash iterations (1 byte) |
|
* Encrypted key (arbitrary) |
|
* |
|
* (ECRYPTFS_SALT_SIZE + 7) minimum packet size |
|
*/ |
|
if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) { |
|
printk(KERN_ERR "Max packet size too large\n"); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) { |
|
printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n", |
|
ECRYPTFS_TAG_3_PACKET_TYPE); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
/* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or |
|
* at end of function upon failure */ |
|
auth_tok_list_item = |
|
kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL); |
|
if (!auth_tok_list_item) { |
|
printk(KERN_ERR "Unable to allocate memory\n"); |
|
rc = -ENOMEM; |
|
goto out; |
|
} |
|
(*new_auth_tok) = &auth_tok_list_item->auth_tok; |
|
rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, |
|
&length_size); |
|
if (rc) { |
|
printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n", |
|
rc); |
|
goto out_free; |
|
} |
|
if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) { |
|
printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); |
|
rc = -EINVAL; |
|
goto out_free; |
|
} |
|
(*packet_size) += length_size; |
|
if (unlikely((*packet_size) + body_size > max_packet_size)) { |
|
printk(KERN_ERR "Packet size exceeds max\n"); |
|
rc = -EINVAL; |
|
goto out_free; |
|
} |
|
(*new_auth_tok)->session_key.encrypted_key_size = |
|
(body_size - (ECRYPTFS_SALT_SIZE + 5)); |
|
if ((*new_auth_tok)->session_key.encrypted_key_size |
|
> ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) { |
|
printk(KERN_WARNING "Tag 3 packet contains key larger " |
|
"than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n"); |
|
rc = -EINVAL; |
|
goto out_free; |
|
} |
|
if (unlikely(data[(*packet_size)++] != 0x04)) { |
|
printk(KERN_WARNING "Unknown version number [%d]\n", |
|
data[(*packet_size) - 1]); |
|
rc = -EINVAL; |
|
goto out_free; |
|
} |
|
rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, |
|
(u16)data[(*packet_size)]); |
|
if (rc) |
|
goto out_free; |
|
/* A little extra work to differentiate among the AES key |
|
* sizes; see RFC2440 */ |
|
switch(data[(*packet_size)++]) { |
|
case RFC2440_CIPHER_AES_192: |
|
crypt_stat->key_size = 24; |
|
break; |
|
default: |
|
crypt_stat->key_size = |
|
(*new_auth_tok)->session_key.encrypted_key_size; |
|
} |
|
rc = ecryptfs_init_crypt_ctx(crypt_stat); |
|
if (rc) |
|
goto out_free; |
|
if (unlikely(data[(*packet_size)++] != 0x03)) { |
|
printk(KERN_WARNING "Only S2K ID 3 is currently supported\n"); |
|
rc = -ENOSYS; |
|
goto out_free; |
|
} |
|
/* TODO: finish the hash mapping */ |
|
switch (data[(*packet_size)++]) { |
|
case 0x01: /* See RFC2440 for these numbers and their mappings */ |
|
/* Choose MD5 */ |
|
memcpy((*new_auth_tok)->token.password.salt, |
|
&data[(*packet_size)], ECRYPTFS_SALT_SIZE); |
|
(*packet_size) += ECRYPTFS_SALT_SIZE; |
|
/* This conversion was taken straight from RFC2440 */ |
|
(*new_auth_tok)->token.password.hash_iterations = |
|
((u32) 16 + (data[(*packet_size)] & 15)) |
|
<< ((data[(*packet_size)] >> 4) + 6); |
|
(*packet_size)++; |
|
/* Friendly reminder: |
|
* (*new_auth_tok)->session_key.encrypted_key_size = |
|
* (body_size - (ECRYPTFS_SALT_SIZE + 5)); */ |
|
memcpy((*new_auth_tok)->session_key.encrypted_key, |
|
&data[(*packet_size)], |
|
(*new_auth_tok)->session_key.encrypted_key_size); |
|
(*packet_size) += |
|
(*new_auth_tok)->session_key.encrypted_key_size; |
|
(*new_auth_tok)->session_key.flags &= |
|
~ECRYPTFS_CONTAINS_DECRYPTED_KEY; |
|
(*new_auth_tok)->session_key.flags |= |
|
ECRYPTFS_CONTAINS_ENCRYPTED_KEY; |
|
(*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */ |
|
break; |
|
default: |
|
ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: " |
|
"[%d]\n", data[(*packet_size) - 1]); |
|
rc = -ENOSYS; |
|
goto out_free; |
|
} |
|
(*new_auth_tok)->token_type = ECRYPTFS_PASSWORD; |
|
/* TODO: Parametarize; we might actually want userspace to |
|
* decrypt the session key. */ |
|
(*new_auth_tok)->session_key.flags &= |
|
~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT); |
|
(*new_auth_tok)->session_key.flags &= |
|
~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT); |
|
list_add(&auth_tok_list_item->list, auth_tok_list); |
|
goto out; |
|
out_free: |
|
(*new_auth_tok) = NULL; |
|
memset(auth_tok_list_item, 0, |
|
sizeof(struct ecryptfs_auth_tok_list_item)); |
|
kmem_cache_free(ecryptfs_auth_tok_list_item_cache, |
|
auth_tok_list_item); |
|
out: |
|
if (rc) |
|
(*packet_size) = 0; |
|
return rc; |
|
} |
|
|
|
/** |
|
* parse_tag_11_packet |
|
* @data: The raw bytes of the packet |
|
* @contents: This function writes the data contents of the literal |
|
* packet into this memory location |
|
* @max_contents_bytes: The maximum number of bytes that this function |
|
* is allowed to write into contents |
|
* @tag_11_contents_size: This function writes the size of the parsed |
|
* contents into this memory location; zero on |
|
* error |
|
* @packet_size: This function writes the size of the parsed packet |
|
* into this memory location; zero on error |
|
* @max_packet_size: maximum number of bytes to parse |
|
* |
|
* Returns zero on success; non-zero on error. |
|
*/ |
|
static int |
|
parse_tag_11_packet(unsigned char *data, unsigned char *contents, |
|
size_t max_contents_bytes, size_t *tag_11_contents_size, |
|
size_t *packet_size, size_t max_packet_size) |
|
{ |
|
size_t body_size; |
|
size_t length_size; |
|
int rc = 0; |
|
|
|
(*packet_size) = 0; |
|
(*tag_11_contents_size) = 0; |
|
/* This format is inspired by OpenPGP; see RFC 2440 |
|
* packet tag 11 |
|
* |
|
* Tag 11 identifier (1 byte) |
|
* Max Tag 11 packet size (max 3 bytes) |
|
* Binary format specifier (1 byte) |
|
* Filename length (1 byte) |
|
* Filename ("_CONSOLE") (8 bytes) |
|
* Modification date (4 bytes) |
|
* Literal data (arbitrary) |
|
* |
|
* We need at least 16 bytes of data for the packet to even be |
|
* valid. |
|
*/ |
|
if (max_packet_size < 16) { |
|
printk(KERN_ERR "Maximum packet size too small\n"); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) { |
|
printk(KERN_WARNING "Invalid tag 11 packet format\n"); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size, |
|
&length_size); |
|
if (rc) { |
|
printk(KERN_WARNING "Invalid tag 11 packet format\n"); |
|
goto out; |
|
} |
|
if (body_size < 14) { |
|
printk(KERN_WARNING "Invalid body size ([%td])\n", body_size); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
(*packet_size) += length_size; |
|
(*tag_11_contents_size) = (body_size - 14); |
|
if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) { |
|
printk(KERN_ERR "Packet size exceeds max\n"); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
if (unlikely((*tag_11_contents_size) > max_contents_bytes)) { |
|
printk(KERN_ERR "Literal data section in tag 11 packet exceeds " |
|
"expected size\n"); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
if (data[(*packet_size)++] != 0x62) { |
|
printk(KERN_WARNING "Unrecognizable packet\n"); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
if (data[(*packet_size)++] != 0x08) { |
|
printk(KERN_WARNING "Unrecognizable packet\n"); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
(*packet_size) += 12; /* Ignore filename and modification date */ |
|
memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size)); |
|
(*packet_size) += (*tag_11_contents_size); |
|
out: |
|
if (rc) { |
|
(*packet_size) = 0; |
|
(*tag_11_contents_size) = 0; |
|
} |
|
return rc; |
|
} |
|
|
|
int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key, |
|
struct ecryptfs_auth_tok **auth_tok, |
|
char *sig) |
|
{ |
|
int rc = 0; |
|
|
|
(*auth_tok_key) = request_key(&key_type_user, sig, NULL); |
|
if (IS_ERR(*auth_tok_key)) { |
|
(*auth_tok_key) = ecryptfs_get_encrypted_key(sig); |
|
if (IS_ERR(*auth_tok_key)) { |
|
printk(KERN_ERR "Could not find key with description: [%s]\n", |
|
sig); |
|
rc = process_request_key_err(PTR_ERR(*auth_tok_key)); |
|
(*auth_tok_key) = NULL; |
|
goto out; |
|
} |
|
} |
|
down_write(&(*auth_tok_key)->sem); |
|
rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok); |
|
if (rc) { |
|
up_write(&(*auth_tok_key)->sem); |
|
key_put(*auth_tok_key); |
|
(*auth_tok_key) = NULL; |
|
goto out; |
|
} |
|
out: |
|
return rc; |
|
} |
|
|
|
/** |
|
* decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok. |
|
* @auth_tok: The passphrase authentication token to use to encrypt the FEK |
|
* @crypt_stat: The cryptographic context |
|
* |
|
* Returns zero on success; non-zero error otherwise |
|
*/ |
|
static int |
|
decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok, |
|
struct ecryptfs_crypt_stat *crypt_stat) |
|
{ |
|
struct scatterlist dst_sg[2]; |
|
struct scatterlist src_sg[2]; |
|
struct mutex *tfm_mutex; |
|
struct crypto_skcipher *tfm; |
|
struct skcipher_request *req = NULL; |
|
int rc = 0; |
|
|
|
if (unlikely(ecryptfs_verbosity > 0)) { |
|
ecryptfs_printk( |
|
KERN_DEBUG, "Session key encryption key (size [%d]):\n", |
|
auth_tok->token.password.session_key_encryption_key_bytes); |
|
ecryptfs_dump_hex( |
|
auth_tok->token.password.session_key_encryption_key, |
|
auth_tok->token.password.session_key_encryption_key_bytes); |
|
} |
|
rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex, |
|
crypt_stat->cipher); |
|
if (unlikely(rc)) { |
|
printk(KERN_ERR "Internal error whilst attempting to get " |
|
"tfm and mutex for cipher name [%s]; rc = [%d]\n", |
|
crypt_stat->cipher, rc); |
|
goto out; |
|
} |
|
rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key, |
|
auth_tok->session_key.encrypted_key_size, |
|
src_sg, 2); |
|
if (rc < 1 || rc > 2) { |
|
printk(KERN_ERR "Internal error whilst attempting to convert " |
|
"auth_tok->session_key.encrypted_key to scatterlist; " |
|
"expected rc = 1; got rc = [%d]. " |
|
"auth_tok->session_key.encrypted_key_size = [%d]\n", rc, |
|
auth_tok->session_key.encrypted_key_size); |
|
goto out; |
|
} |
|
auth_tok->session_key.decrypted_key_size = |
|
auth_tok->session_key.encrypted_key_size; |
|
rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key, |
|
auth_tok->session_key.decrypted_key_size, |
|
dst_sg, 2); |
|
if (rc < 1 || rc > 2) { |
|
printk(KERN_ERR "Internal error whilst attempting to convert " |
|
"auth_tok->session_key.decrypted_key to scatterlist; " |
|
"expected rc = 1; got rc = [%d]\n", rc); |
|
goto out; |
|
} |
|
mutex_lock(tfm_mutex); |
|
req = skcipher_request_alloc(tfm, GFP_KERNEL); |
|
if (!req) { |
|
mutex_unlock(tfm_mutex); |
|
printk(KERN_ERR "%s: Out of kernel memory whilst attempting to " |
|
"skcipher_request_alloc for %s\n", __func__, |
|
crypto_skcipher_driver_name(tfm)); |
|
rc = -ENOMEM; |
|
goto out; |
|
} |
|
|
|
skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, |
|
NULL, NULL); |
|
rc = crypto_skcipher_setkey( |
|
tfm, auth_tok->token.password.session_key_encryption_key, |
|
crypt_stat->key_size); |
|
if (unlikely(rc < 0)) { |
|
mutex_unlock(tfm_mutex); |
|
printk(KERN_ERR "Error setting key for crypto context\n"); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
skcipher_request_set_crypt(req, src_sg, dst_sg, |
|
auth_tok->session_key.encrypted_key_size, |
|
NULL); |
|
rc = crypto_skcipher_decrypt(req); |
|
mutex_unlock(tfm_mutex); |
|
if (unlikely(rc)) { |
|
printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc); |
|
goto out; |
|
} |
|
auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY; |
|
memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key, |
|
auth_tok->session_key.decrypted_key_size); |
|
crypt_stat->flags |= ECRYPTFS_KEY_VALID; |
|
if (unlikely(ecryptfs_verbosity > 0)) { |
|
ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n", |
|
crypt_stat->key_size); |
|
ecryptfs_dump_hex(crypt_stat->key, |
|
crypt_stat->key_size); |
|
} |
|
out: |
|
skcipher_request_free(req); |
|
return rc; |
|
} |
|
|
|
/** |
|
* ecryptfs_parse_packet_set |
|
* @crypt_stat: The cryptographic context |
|
* @src: Virtual address of region of memory containing the packets |
|
* @ecryptfs_dentry: The eCryptfs dentry associated with the packet set |
|
* |
|
* Get crypt_stat to have the file's session key if the requisite key |
|
* is available to decrypt the session key. |
|
* |
|
* Returns Zero if a valid authentication token was retrieved and |
|
* processed; negative value for file not encrypted or for error |
|
* conditions. |
|
*/ |
|
int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat, |
|
unsigned char *src, |
|
struct dentry *ecryptfs_dentry) |
|
{ |
|
size_t i = 0; |
|
size_t found_auth_tok; |
|
size_t next_packet_is_auth_tok_packet; |
|
struct list_head auth_tok_list; |
|
struct ecryptfs_auth_tok *matching_auth_tok; |
|
struct ecryptfs_auth_tok *candidate_auth_tok; |
|
char *candidate_auth_tok_sig; |
|
size_t packet_size; |
|
struct ecryptfs_auth_tok *new_auth_tok; |
|
unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE]; |
|
struct ecryptfs_auth_tok_list_item *auth_tok_list_item; |
|
size_t tag_11_contents_size; |
|
size_t tag_11_packet_size; |
|
struct key *auth_tok_key = NULL; |
|
int rc = 0; |
|
|
|
INIT_LIST_HEAD(&auth_tok_list); |
|
/* Parse the header to find as many packets as we can; these will be |
|
* added the our &auth_tok_list */ |
|
next_packet_is_auth_tok_packet = 1; |
|
while (next_packet_is_auth_tok_packet) { |
|
size_t max_packet_size = ((PAGE_SIZE - 8) - i); |
|
|
|
switch (src[i]) { |
|
case ECRYPTFS_TAG_3_PACKET_TYPE: |
|
rc = parse_tag_3_packet(crypt_stat, |
|
(unsigned char *)&src[i], |
|
&auth_tok_list, &new_auth_tok, |
|
&packet_size, max_packet_size); |
|
if (rc) { |
|
ecryptfs_printk(KERN_ERR, "Error parsing " |
|
"tag 3 packet\n"); |
|
rc = -EIO; |
|
goto out_wipe_list; |
|
} |
|
i += packet_size; |
|
rc = parse_tag_11_packet((unsigned char *)&src[i], |
|
sig_tmp_space, |
|
ECRYPTFS_SIG_SIZE, |
|
&tag_11_contents_size, |
|
&tag_11_packet_size, |
|
max_packet_size); |
|
if (rc) { |
|
ecryptfs_printk(KERN_ERR, "No valid " |
|
"(ecryptfs-specific) literal " |
|
"packet containing " |
|
"authentication token " |
|
"signature found after " |
|
"tag 3 packet\n"); |
|
rc = -EIO; |
|
goto out_wipe_list; |
|
} |
|
i += tag_11_packet_size; |
|
if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) { |
|
ecryptfs_printk(KERN_ERR, "Expected " |
|
"signature of size [%d]; " |
|
"read size [%zd]\n", |
|
ECRYPTFS_SIG_SIZE, |
|
tag_11_contents_size); |
|
rc = -EIO; |
|
goto out_wipe_list; |
|
} |
|
ecryptfs_to_hex(new_auth_tok->token.password.signature, |
|
sig_tmp_space, tag_11_contents_size); |
|
new_auth_tok->token.password.signature[ |
|
ECRYPTFS_PASSWORD_SIG_SIZE] = '\0'; |
|
crypt_stat->flags |= ECRYPTFS_ENCRYPTED; |
|
break; |
|
case ECRYPTFS_TAG_1_PACKET_TYPE: |
|
rc = parse_tag_1_packet(crypt_stat, |
|
(unsigned char *)&src[i], |
|
&auth_tok_list, &new_auth_tok, |
|
&packet_size, max_packet_size); |
|
if (rc) { |
|
ecryptfs_printk(KERN_ERR, "Error parsing " |
|
"tag 1 packet\n"); |
|
rc = -EIO; |
|
goto out_wipe_list; |
|
} |
|
i += packet_size; |
|
crypt_stat->flags |= ECRYPTFS_ENCRYPTED; |
|
break; |
|
case ECRYPTFS_TAG_11_PACKET_TYPE: |
|
ecryptfs_printk(KERN_WARNING, "Invalid packet set " |
|
"(Tag 11 not allowed by itself)\n"); |
|
rc = -EIO; |
|
goto out_wipe_list; |
|
default: |
|
ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] " |
|
"of the file header; hex value of " |
|
"character is [0x%.2x]\n", i, src[i]); |
|
next_packet_is_auth_tok_packet = 0; |
|
} |
|
} |
|
if (list_empty(&auth_tok_list)) { |
|
printk(KERN_ERR "The lower file appears to be a non-encrypted " |
|
"eCryptfs file; this is not supported in this version " |
|
"of the eCryptfs kernel module\n"); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
/* auth_tok_list contains the set of authentication tokens |
|
* parsed from the metadata. We need to find a matching |
|
* authentication token that has the secret component(s) |
|
* necessary to decrypt the EFEK in the auth_tok parsed from |
|
* the metadata. There may be several potential matches, but |
|
* just one will be sufficient to decrypt to get the FEK. */ |
|
find_next_matching_auth_tok: |
|
found_auth_tok = 0; |
|
list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) { |
|
candidate_auth_tok = &auth_tok_list_item->auth_tok; |
|
if (unlikely(ecryptfs_verbosity > 0)) { |
|
ecryptfs_printk(KERN_DEBUG, |
|
"Considering candidate auth tok:\n"); |
|
ecryptfs_dump_auth_tok(candidate_auth_tok); |
|
} |
|
rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig, |
|
candidate_auth_tok); |
|
if (rc) { |
|
printk(KERN_ERR |
|
"Unrecognized candidate auth tok type: [%d]\n", |
|
candidate_auth_tok->token_type); |
|
rc = -EINVAL; |
|
goto out_wipe_list; |
|
} |
|
rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key, |
|
&matching_auth_tok, |
|
crypt_stat->mount_crypt_stat, |
|
candidate_auth_tok_sig); |
|
if (!rc) { |
|
found_auth_tok = 1; |
|
goto found_matching_auth_tok; |
|
} |
|
} |
|
if (!found_auth_tok) { |
|
ecryptfs_printk(KERN_ERR, "Could not find a usable " |
|
"authentication token\n"); |
|
rc = -EIO; |
|
goto out_wipe_list; |
|
} |
|
found_matching_auth_tok: |
|
if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) { |
|
memcpy(&(candidate_auth_tok->token.private_key), |
|
&(matching_auth_tok->token.private_key), |
|
sizeof(struct ecryptfs_private_key)); |
|
up_write(&(auth_tok_key->sem)); |
|
key_put(auth_tok_key); |
|
rc = decrypt_pki_encrypted_session_key(candidate_auth_tok, |
|
crypt_stat); |
|
} else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) { |
|
memcpy(&(candidate_auth_tok->token.password), |
|
&(matching_auth_tok->token.password), |
|
sizeof(struct ecryptfs_password)); |
|
up_write(&(auth_tok_key->sem)); |
|
key_put(auth_tok_key); |
|
rc = decrypt_passphrase_encrypted_session_key( |
|
candidate_auth_tok, crypt_stat); |
|
} else { |
|
up_write(&(auth_tok_key->sem)); |
|
key_put(auth_tok_key); |
|
rc = -EINVAL; |
|
} |
|
if (rc) { |
|
struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp; |
|
|
|
ecryptfs_printk(KERN_WARNING, "Error decrypting the " |
|
"session key for authentication token with sig " |
|
"[%.*s]; rc = [%d]. Removing auth tok " |
|
"candidate from the list and searching for " |
|
"the next match.\n", ECRYPTFS_SIG_SIZE_HEX, |
|
candidate_auth_tok_sig, rc); |
|
list_for_each_entry_safe(auth_tok_list_item, |
|
auth_tok_list_item_tmp, |
|
&auth_tok_list, list) { |
|
if (candidate_auth_tok |
|
== &auth_tok_list_item->auth_tok) { |
|
list_del(&auth_tok_list_item->list); |
|
kmem_cache_free( |
|
ecryptfs_auth_tok_list_item_cache, |
|
auth_tok_list_item); |
|
goto find_next_matching_auth_tok; |
|
} |
|
} |
|
BUG(); |
|
} |
|
rc = ecryptfs_compute_root_iv(crypt_stat); |
|
if (rc) { |
|
ecryptfs_printk(KERN_ERR, "Error computing " |
|
"the root IV\n"); |
|
goto out_wipe_list; |
|
} |
|
rc = ecryptfs_init_crypt_ctx(crypt_stat); |
|
if (rc) { |
|
ecryptfs_printk(KERN_ERR, "Error initializing crypto " |
|
"context for cipher [%s]; rc = [%d]\n", |
|
crypt_stat->cipher, rc); |
|
} |
|
out_wipe_list: |
|
wipe_auth_tok_list(&auth_tok_list); |
|
out: |
|
return rc; |
|
} |
|
|
|
static int |
|
pki_encrypt_session_key(struct key *auth_tok_key, |
|
struct ecryptfs_auth_tok *auth_tok, |
|
struct ecryptfs_crypt_stat *crypt_stat, |
|
struct ecryptfs_key_record *key_rec) |
|
{ |
|
struct ecryptfs_msg_ctx *msg_ctx = NULL; |
|
char *payload = NULL; |
|
size_t payload_len = 0; |
|
struct ecryptfs_message *msg; |
|
int rc; |
|
|
|
rc = write_tag_66_packet(auth_tok->token.private_key.signature, |
|
ecryptfs_code_for_cipher_string( |
|
crypt_stat->cipher, |
|
crypt_stat->key_size), |
|
crypt_stat, &payload, &payload_len); |
|
up_write(&(auth_tok_key->sem)); |
|
key_put(auth_tok_key); |
|
if (rc) { |
|
ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n"); |
|
goto out; |
|
} |
|
rc = ecryptfs_send_message(payload, payload_len, &msg_ctx); |
|
if (rc) { |
|
ecryptfs_printk(KERN_ERR, "Error sending message to " |
|
"ecryptfsd: %d\n", rc); |
|
goto out; |
|
} |
|
rc = ecryptfs_wait_for_response(msg_ctx, &msg); |
|
if (rc) { |
|
ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet " |
|
"from the user space daemon\n"); |
|
rc = -EIO; |
|
goto out; |
|
} |
|
rc = parse_tag_67_packet(key_rec, msg); |
|
if (rc) |
|
ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n"); |
|
kfree(msg); |
|
out: |
|
kfree(payload); |
|
return rc; |
|
} |
|
/** |
|
* write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet |
|
* @dest: Buffer into which to write the packet |
|
* @remaining_bytes: Maximum number of bytes that can be writtn |
|
* @auth_tok_key: The authentication token key to unlock and put when done with |
|
* @auth_tok |
|
* @auth_tok: The authentication token used for generating the tag 1 packet |
|
* @crypt_stat: The cryptographic context |
|
* @key_rec: The key record struct for the tag 1 packet |
|
* @packet_size: This function will write the number of bytes that end |
|
* up constituting the packet; set to zero on error |
|
* |
|
* Returns zero on success; non-zero on error. |
|
*/ |
|
static int |
|
write_tag_1_packet(char *dest, size_t *remaining_bytes, |
|
struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok, |
|
struct ecryptfs_crypt_stat *crypt_stat, |
|
struct ecryptfs_key_record *key_rec, size_t *packet_size) |
|
{ |
|
size_t i; |
|
size_t encrypted_session_key_valid = 0; |
|
size_t packet_size_length; |
|
size_t max_packet_size; |
|
int rc = 0; |
|
|
|
(*packet_size) = 0; |
|
ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature, |
|
ECRYPTFS_SIG_SIZE); |
|
encrypted_session_key_valid = 0; |
|
for (i = 0; i < crypt_stat->key_size; i++) |
|
encrypted_session_key_valid |= |
|
auth_tok->session_key.encrypted_key[i]; |
|
if (encrypted_session_key_valid) { |
|
memcpy(key_rec->enc_key, |
|
auth_tok->session_key.encrypted_key, |
|
auth_tok->session_key.encrypted_key_size); |
|
up_write(&(auth_tok_key->sem)); |
|
key_put(auth_tok_key); |
|
goto encrypted_session_key_set; |
|
} |
|
if (auth_tok->session_key.encrypted_key_size == 0) |
|
auth_tok->session_key.encrypted_key_size = |
|
auth_tok->token.private_key.key_size; |
|
rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat, |
|
key_rec); |
|
if (rc) { |
|
printk(KERN_ERR "Failed to encrypt session key via a key " |
|
"module; rc = [%d]\n", rc); |
|
goto out; |
|
} |
|
if (ecryptfs_verbosity > 0) { |
|
ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n"); |
|
ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size); |
|
} |
|
encrypted_session_key_set: |
|
/* This format is inspired by OpenPGP; see RFC 2440 |
|
* packet tag 1 */ |
|
max_packet_size = (1 /* Tag 1 identifier */ |
|
+ 3 /* Max Tag 1 packet size */ |
|
+ 1 /* Version */ |
|
+ ECRYPTFS_SIG_SIZE /* Key identifier */ |
|
+ 1 /* Cipher identifier */ |
|
+ key_rec->enc_key_size); /* Encrypted key size */ |
|
if (max_packet_size > (*remaining_bytes)) { |
|
printk(KERN_ERR "Packet length larger than maximum allowable; " |
|
"need up to [%td] bytes, but there are only [%td] " |
|
"available\n", max_packet_size, (*remaining_bytes)); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE; |
|
rc = ecryptfs_write_packet_length(&dest[(*packet_size)], |
|
(max_packet_size - 4), |
|
&packet_size_length); |
|
if (rc) { |
|
ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet " |
|
"header; cannot generate packet length\n"); |
|
goto out; |
|
} |
|
(*packet_size) += packet_size_length; |
|
dest[(*packet_size)++] = 0x03; /* version 3 */ |
|
memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE); |
|
(*packet_size) += ECRYPTFS_SIG_SIZE; |
|
dest[(*packet_size)++] = RFC2440_CIPHER_RSA; |
|
memcpy(&dest[(*packet_size)], key_rec->enc_key, |
|
key_rec->enc_key_size); |
|
(*packet_size) += key_rec->enc_key_size; |
|
out: |
|
if (rc) |
|
(*packet_size) = 0; |
|
else |
|
(*remaining_bytes) -= (*packet_size); |
|
return rc; |
|
} |
|
|
|
/** |
|
* write_tag_11_packet |
|
* @dest: Target into which Tag 11 packet is to be written |
|
* @remaining_bytes: Maximum packet length |
|
* @contents: Byte array of contents to copy in |
|
* @contents_length: Number of bytes in contents |
|
* @packet_length: Length of the Tag 11 packet written; zero on error |
|
* |
|
* Returns zero on success; non-zero on error. |
|
*/ |
|
static int |
|
write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents, |
|
size_t contents_length, size_t *packet_length) |
|
{ |
|
size_t packet_size_length; |
|
size_t max_packet_size; |
|
int rc = 0; |
|
|
|
(*packet_length) = 0; |
|
/* This format is inspired by OpenPGP; see RFC 2440 |
|
* packet tag 11 */ |
|
max_packet_size = (1 /* Tag 11 identifier */ |
|
+ 3 /* Max Tag 11 packet size */ |
|
+ 1 /* Binary format specifier */ |
|
+ 1 /* Filename length */ |
|
+ 8 /* Filename ("_CONSOLE") */ |
|
+ 4 /* Modification date */ |
|
+ contents_length); /* Literal data */ |
|
if (max_packet_size > (*remaining_bytes)) { |
|
printk(KERN_ERR "Packet length larger than maximum allowable; " |
|
"need up to [%td] bytes, but there are only [%td] " |
|
"available\n", max_packet_size, (*remaining_bytes)); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE; |
|
rc = ecryptfs_write_packet_length(&dest[(*packet_length)], |
|
(max_packet_size - 4), |
|
&packet_size_length); |
|
if (rc) { |
|
printk(KERN_ERR "Error generating tag 11 packet header; cannot " |
|
"generate packet length. rc = [%d]\n", rc); |
|
goto out; |
|
} |
|
(*packet_length) += packet_size_length; |
|
dest[(*packet_length)++] = 0x62; /* binary data format specifier */ |
|
dest[(*packet_length)++] = 8; |
|
memcpy(&dest[(*packet_length)], "_CONSOLE", 8); |
|
(*packet_length) += 8; |
|
memset(&dest[(*packet_length)], 0x00, 4); |
|
(*packet_length) += 4; |
|
memcpy(&dest[(*packet_length)], contents, contents_length); |
|
(*packet_length) += contents_length; |
|
out: |
|
if (rc) |
|
(*packet_length) = 0; |
|
else |
|
(*remaining_bytes) -= (*packet_length); |
|
return rc; |
|
} |
|
|
|
/** |
|
* write_tag_3_packet |
|
* @dest: Buffer into which to write the packet |
|
* @remaining_bytes: Maximum number of bytes that can be written |
|
* @auth_tok: Authentication token |
|
* @crypt_stat: The cryptographic context |
|
* @key_rec: encrypted key |
|
* @packet_size: This function will write the number of bytes that end |
|
* up constituting the packet; set to zero on error |
|
* |
|
* Returns zero on success; non-zero on error. |
|
*/ |
|
static int |
|
write_tag_3_packet(char *dest, size_t *remaining_bytes, |
|
struct ecryptfs_auth_tok *auth_tok, |
|
struct ecryptfs_crypt_stat *crypt_stat, |
|
struct ecryptfs_key_record *key_rec, size_t *packet_size) |
|
{ |
|
size_t i; |
|
size_t encrypted_session_key_valid = 0; |
|
char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES]; |
|
struct scatterlist dst_sg[2]; |
|
struct scatterlist src_sg[2]; |
|
struct mutex *tfm_mutex = NULL; |
|
u8 cipher_code; |
|
size_t packet_size_length; |
|
size_t max_packet_size; |
|
struct ecryptfs_mount_crypt_stat *mount_crypt_stat = |
|
crypt_stat->mount_crypt_stat; |
|
struct crypto_skcipher *tfm; |
|
struct skcipher_request *req; |
|
int rc = 0; |
|
|
|
(*packet_size) = 0; |
|
ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature, |
|
ECRYPTFS_SIG_SIZE); |
|
rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex, |
|
crypt_stat->cipher); |
|
if (unlikely(rc)) { |
|
printk(KERN_ERR "Internal error whilst attempting to get " |
|
"tfm and mutex for cipher name [%s]; rc = [%d]\n", |
|
crypt_stat->cipher, rc); |
|
goto out; |
|
} |
|
if (mount_crypt_stat->global_default_cipher_key_size == 0) { |
|
printk(KERN_WARNING "No key size specified at mount; " |
|
"defaulting to [%d]\n", |
|
crypto_skcipher_max_keysize(tfm)); |
|
mount_crypt_stat->global_default_cipher_key_size = |
|
crypto_skcipher_max_keysize(tfm); |
|
} |
|
if (crypt_stat->key_size == 0) |
|
crypt_stat->key_size = |
|
mount_crypt_stat->global_default_cipher_key_size; |
|
if (auth_tok->session_key.encrypted_key_size == 0) |
|
auth_tok->session_key.encrypted_key_size = |
|
crypt_stat->key_size; |
|
if (crypt_stat->key_size == 24 |
|
&& strcmp("aes", crypt_stat->cipher) == 0) { |
|
memset((crypt_stat->key + 24), 0, 8); |
|
auth_tok->session_key.encrypted_key_size = 32; |
|
} else |
|
auth_tok->session_key.encrypted_key_size = crypt_stat->key_size; |
|
key_rec->enc_key_size = |
|
auth_tok->session_key.encrypted_key_size; |
|
encrypted_session_key_valid = 0; |
|
for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++) |
|
encrypted_session_key_valid |= |
|
auth_tok->session_key.encrypted_key[i]; |
|
if (encrypted_session_key_valid) { |
|
ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; " |
|
"using auth_tok->session_key.encrypted_key, " |
|
"where key_rec->enc_key_size = [%zd]\n", |
|
key_rec->enc_key_size); |
|
memcpy(key_rec->enc_key, |
|
auth_tok->session_key.encrypted_key, |
|
key_rec->enc_key_size); |
|
goto encrypted_session_key_set; |
|
} |
|
if (auth_tok->token.password.flags & |
|
ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) { |
|
ecryptfs_printk(KERN_DEBUG, "Using previously generated " |
|
"session key encryption key of size [%d]\n", |
|
auth_tok->token.password. |
|
session_key_encryption_key_bytes); |
|
memcpy(session_key_encryption_key, |
|
auth_tok->token.password.session_key_encryption_key, |
|
crypt_stat->key_size); |
|
ecryptfs_printk(KERN_DEBUG, |
|
"Cached session key encryption key:\n"); |
|
if (ecryptfs_verbosity > 0) |
|
ecryptfs_dump_hex(session_key_encryption_key, 16); |
|
} |
|
if (unlikely(ecryptfs_verbosity > 0)) { |
|
ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n"); |
|
ecryptfs_dump_hex(session_key_encryption_key, 16); |
|
} |
|
rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size, |
|
src_sg, 2); |
|
if (rc < 1 || rc > 2) { |
|
ecryptfs_printk(KERN_ERR, "Error generating scatterlist " |
|
"for crypt_stat session key; expected rc = 1; " |
|
"got rc = [%d]. key_rec->enc_key_size = [%zd]\n", |
|
rc, key_rec->enc_key_size); |
|
rc = -ENOMEM; |
|
goto out; |
|
} |
|
rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size, |
|
dst_sg, 2); |
|
if (rc < 1 || rc > 2) { |
|
ecryptfs_printk(KERN_ERR, "Error generating scatterlist " |
|
"for crypt_stat encrypted session key; " |
|
"expected rc = 1; got rc = [%d]. " |
|
"key_rec->enc_key_size = [%zd]\n", rc, |
|
key_rec->enc_key_size); |
|
rc = -ENOMEM; |
|
goto out; |
|
} |
|
mutex_lock(tfm_mutex); |
|
rc = crypto_skcipher_setkey(tfm, session_key_encryption_key, |
|
crypt_stat->key_size); |
|
if (rc < 0) { |
|
mutex_unlock(tfm_mutex); |
|
ecryptfs_printk(KERN_ERR, "Error setting key for crypto " |
|
"context; rc = [%d]\n", rc); |
|
goto out; |
|
} |
|
|
|
req = skcipher_request_alloc(tfm, GFP_KERNEL); |
|
if (!req) { |
|
mutex_unlock(tfm_mutex); |
|
ecryptfs_printk(KERN_ERR, "Out of kernel memory whilst " |
|
"attempting to skcipher_request_alloc for " |
|
"%s\n", crypto_skcipher_driver_name(tfm)); |
|
rc = -ENOMEM; |
|
goto out; |
|
} |
|
|
|
skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, |
|
NULL, NULL); |
|
|
|
rc = 0; |
|
ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n", |
|
crypt_stat->key_size); |
|
skcipher_request_set_crypt(req, src_sg, dst_sg, |
|
(*key_rec).enc_key_size, NULL); |
|
rc = crypto_skcipher_encrypt(req); |
|
mutex_unlock(tfm_mutex); |
|
skcipher_request_free(req); |
|
if (rc) { |
|
printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc); |
|
goto out; |
|
} |
|
ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n"); |
|
if (ecryptfs_verbosity > 0) { |
|
ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n", |
|
key_rec->enc_key_size); |
|
ecryptfs_dump_hex(key_rec->enc_key, |
|
key_rec->enc_key_size); |
|
} |
|
encrypted_session_key_set: |
|
/* This format is inspired by OpenPGP; see RFC 2440 |
|
* packet tag 3 */ |
|
max_packet_size = (1 /* Tag 3 identifier */ |
|
+ 3 /* Max Tag 3 packet size */ |
|
+ 1 /* Version */ |
|
+ 1 /* Cipher code */ |
|
+ 1 /* S2K specifier */ |
|
+ 1 /* Hash identifier */ |
|
+ ECRYPTFS_SALT_SIZE /* Salt */ |
|
+ 1 /* Hash iterations */ |
|
+ key_rec->enc_key_size); /* Encrypted key size */ |
|
if (max_packet_size > (*remaining_bytes)) { |
|
printk(KERN_ERR "Packet too large; need up to [%td] bytes, but " |
|
"there are only [%td] available\n", max_packet_size, |
|
(*remaining_bytes)); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE; |
|
/* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3) |
|
* to get the number of octets in the actual Tag 3 packet */ |
|
rc = ecryptfs_write_packet_length(&dest[(*packet_size)], |
|
(max_packet_size - 4), |
|
&packet_size_length); |
|
if (rc) { |
|
printk(KERN_ERR "Error generating tag 3 packet header; cannot " |
|
"generate packet length. rc = [%d]\n", rc); |
|
goto out; |
|
} |
|
(*packet_size) += packet_size_length; |
|
dest[(*packet_size)++] = 0x04; /* version 4 */ |
|
/* TODO: Break from RFC2440 so that arbitrary ciphers can be |
|
* specified with strings */ |
|
cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher, |
|
crypt_stat->key_size); |
|
if (cipher_code == 0) { |
|
ecryptfs_printk(KERN_WARNING, "Unable to generate code for " |
|
"cipher [%s]\n", crypt_stat->cipher); |
|
rc = -EINVAL; |
|
goto out; |
|
} |
|
dest[(*packet_size)++] = cipher_code; |
|
dest[(*packet_size)++] = 0x03; /* S2K */ |
|
dest[(*packet_size)++] = 0x01; /* MD5 (TODO: parameterize) */ |
|
memcpy(&dest[(*packet_size)], auth_tok->token.password.salt, |
|
ECRYPTFS_SALT_SIZE); |
|
(*packet_size) += ECRYPTFS_SALT_SIZE; /* salt */ |
|
dest[(*packet_size)++] = 0x60; /* hash iterations (65536) */ |
|
memcpy(&dest[(*packet_size)], key_rec->enc_key, |
|
key_rec->enc_key_size); |
|
(*packet_size) += key_rec->enc_key_size; |
|
out: |
|
if (rc) |
|
(*packet_size) = 0; |
|
else |
|
(*remaining_bytes) -= (*packet_size); |
|
return rc; |
|
} |
|
|
|
struct kmem_cache *ecryptfs_key_record_cache; |
|
|
|
/** |
|
* ecryptfs_generate_key_packet_set |
|
* @dest_base: Virtual address from which to write the key record set |
|
* @crypt_stat: The cryptographic context from which the |
|
* authentication tokens will be retrieved |
|
* @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat |
|
* for the global parameters |
|
* @len: The amount written |
|
* @max: The maximum amount of data allowed to be written |
|
* |
|
* Generates a key packet set and writes it to the virtual address |
|
* passed in. |
|
* |
|
* Returns zero on success; non-zero on error. |
|
*/ |
|
int |
|
ecryptfs_generate_key_packet_set(char *dest_base, |
|
struct ecryptfs_crypt_stat *crypt_stat, |
|
struct dentry *ecryptfs_dentry, size_t *len, |
|
size_t max) |
|
{ |
|
struct ecryptfs_auth_tok *auth_tok; |
|
struct key *auth_tok_key = NULL; |
|
struct ecryptfs_mount_crypt_stat *mount_crypt_stat = |
|
&ecryptfs_superblock_to_private( |
|
ecryptfs_dentry->d_sb)->mount_crypt_stat; |
|
size_t written; |
|
struct ecryptfs_key_record *key_rec; |
|
struct ecryptfs_key_sig *key_sig; |
|
int rc = 0; |
|
|
|
(*len) = 0; |
|
mutex_lock(&crypt_stat->keysig_list_mutex); |
|
key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL); |
|
if (!key_rec) { |
|
rc = -ENOMEM; |
|
goto out; |
|
} |
|
list_for_each_entry(key_sig, &crypt_stat->keysig_list, |
|
crypt_stat_list) { |
|
memset(key_rec, 0, sizeof(*key_rec)); |
|
rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key, |
|
&auth_tok, |
|
mount_crypt_stat, |
|
key_sig->keysig); |
|
if (rc) { |
|
printk(KERN_WARNING "Unable to retrieve auth tok with " |
|
"sig = [%s]\n", key_sig->keysig); |
|
rc = process_find_global_auth_tok_for_sig_err(rc); |
|
goto out_free; |
|
} |
|
if (auth_tok->token_type == ECRYPTFS_PASSWORD) { |
|
rc = write_tag_3_packet((dest_base + (*len)), |
|
&max, auth_tok, |
|
crypt_stat, key_rec, |
|
&written); |
|
up_write(&(auth_tok_key->sem)); |
|
key_put(auth_tok_key); |
|
if (rc) { |
|
ecryptfs_printk(KERN_WARNING, "Error " |
|
"writing tag 3 packet\n"); |
|
goto out_free; |
|
} |
|
(*len) += written; |
|
/* Write auth tok signature packet */ |
|
rc = write_tag_11_packet((dest_base + (*len)), &max, |
|
key_rec->sig, |
|
ECRYPTFS_SIG_SIZE, &written); |
|
if (rc) { |
|
ecryptfs_printk(KERN_ERR, "Error writing " |
|
"auth tok signature packet\n"); |
|
goto out_free; |
|
} |
|
(*len) += written; |
|
} else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) { |
|
rc = write_tag_1_packet(dest_base + (*len), &max, |
|
auth_tok_key, auth_tok, |
|
crypt_stat, key_rec, &written); |
|
if (rc) { |
|
ecryptfs_printk(KERN_WARNING, "Error " |
|
"writing tag 1 packet\n"); |
|
goto out_free; |
|
} |
|
(*len) += written; |
|
} else { |
|
up_write(&(auth_tok_key->sem)); |
|
key_put(auth_tok_key); |
|
ecryptfs_printk(KERN_WARNING, "Unsupported " |
|
"authentication token type\n"); |
|
rc = -EINVAL; |
|
goto out_free; |
|
} |
|
} |
|
if (likely(max > 0)) { |
|
dest_base[(*len)] = 0x00; |
|
} else { |
|
ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n"); |
|
rc = -EIO; |
|
} |
|
out_free: |
|
kmem_cache_free(ecryptfs_key_record_cache, key_rec); |
|
out: |
|
if (rc) |
|
(*len) = 0; |
|
mutex_unlock(&crypt_stat->keysig_list_mutex); |
|
return rc; |
|
} |
|
|
|
struct kmem_cache *ecryptfs_key_sig_cache; |
|
|
|
int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig) |
|
{ |
|
struct ecryptfs_key_sig *new_key_sig; |
|
|
|
new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL); |
|
if (!new_key_sig) |
|
return -ENOMEM; |
|
|
|
memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX); |
|
new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0'; |
|
/* Caller must hold keysig_list_mutex */ |
|
list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list); |
|
|
|
return 0; |
|
} |
|
|
|
struct kmem_cache *ecryptfs_global_auth_tok_cache; |
|
|
|
int |
|
ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat, |
|
char *sig, u32 global_auth_tok_flags) |
|
{ |
|
struct ecryptfs_global_auth_tok *new_auth_tok; |
|
|
|
new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache, |
|
GFP_KERNEL); |
|
if (!new_auth_tok) |
|
return -ENOMEM; |
|
|
|
memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX); |
|
new_auth_tok->flags = global_auth_tok_flags; |
|
new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0'; |
|
mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); |
|
list_add(&new_auth_tok->mount_crypt_stat_list, |
|
&mount_crypt_stat->global_auth_tok_list); |
|
mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); |
|
return 0; |
|
} |
|
|
|
|