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keystore.c
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keystore.c
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/**
* eCryptfs: Linux filesystem encryption layer
* In-kernel key management code. Includes functions to parse and
* write authentication token-related packets with the underlying
* file.
*
* Copyright (C) 2004-2006 International Business Machines Corp.
* Author(s): Michael A. Halcrow <[email protected]>
* Michael C. Thompson <[email protected]>
* Trevor S. Highland <[email protected]>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
* 02111-1307, USA.
*/
#include <linux/string.h>
#include <linux/syscalls.h>
#include <linux/pagemap.h>
#include <linux/key.h>
#include <linux/random.h>
#include <linux/crypto.h>
#include <linux/scatterlist.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)
{
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%.16x]\n", err_code);
rc = -EINVAL;
}
return rc;
}
/**
* 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
*
* Returns zero on success; non-zero on error
*/
static int parse_packet_length(unsigned char *data, size_t *size,
size_t *length_size)
{
int rc = 0;
(*length_size) = 0;
(*size) = 0;
if (data[0] < 192) {
/* One-byte length */
(*size) = (unsigned char)data[0];
(*length_size) = 1;
} else if (data[0] < 224) {
/* Two-byte length */
(*size) = (((unsigned char)(data[0]) - 192) * 256);
(*size) += ((unsigned char)(data[1]) + 192);
(*length_size) = 2;
} else if (data[0] == 255) {
/* Five-byte length; we're not supposed to see this */
ecryptfs_printk(KERN_ERR, "Five-byte packet length not "
"supported\n");
rc = -EINVAL;
goto out;
} else {
ecryptfs_printk(KERN_ERR, "Error parsing packet length\n");
rc = -EINVAL;
goto out;
}
out:
return rc;
}
/**
* write_packet_length
* @dest: The byte array target into which to write the length. Must
* have at least 5 bytes allocated.
* @size: The length to write.
* @packet_size_length: The number of bytes used to encode the packet
* length is written to this address.
*
* Returns zero on success; non-zero on error.
*/
static int write_packet_length(char *dest, size_t size,
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);
(*packet_size_length) = 2;
} else {
rc = -EINVAL;
ecryptfs_printk(KERN_WARNING,
"Unsupported packet size: [%d]\n", size);
}
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);
*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 = 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;
rc = 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);
i += session_key->encrypted_key_size;
*packet_len = i;
out:
return rc;
}
static int
parse_tag_65_packet(struct ecryptfs_session_key *session_key, u16 *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");
rc = -EIO;
goto out;
}
if (data[i++]) {
ecryptfs_printk(KERN_ERR, "Status indicator has non-zero value "
"[%d]\n", data[i-1]);
rc = -EIO;
goto out;
}
rc = 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 received netlink message 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",
session_key->decrypted_key_size,
ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
rc = -EIO;
goto out;
}
memcpy(session_key->decrypted_key, &data[i],
session_key->decrypted_key_size);
i += session_key->decrypted_key_size;
expected_checksum += (unsigned char)(data[i++]) << 8;
expected_checksum += (unsigned char)(data[i++]);
for (i = 0; i < session_key->decrypted_key_size; i++)
checksum += session_key->decrypted_key[i];
if (expected_checksum != checksum) {
ecryptfs_printk(KERN_ERR, "Invalid checksum for file "
"encryption key; expected [%x]; calculated "
"[%x]\n", expected_checksum, checksum);
rc = -EIO;
}
out:
return rc;
}
static int
write_tag_66_packet(char *signature, size_t 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 |
* | Key Identifier Size | 1 or 2 bytes |
* | Key Identifier | arbitrary |
* | File Encryption Key Size | 1 or 2 bytes |
* | File Encryption Key | arbitrary |
*/
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 = 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);
i += ECRYPTFS_SIG_SIZE_HEX;
/* The encrypted key includes 1 byte cipher code and 2 byte checksum */
rc = 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;
goto out;
}
if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) {
ecryptfs_printk(KERN_ERR, "Type should be ECRYPTFS_TAG_67\n");
rc = -EIO;
goto out;
}
if (data[i++]) {
ecryptfs_printk(KERN_ERR, "Status indicator has non zero value"
" [%d]\n", data[i-1]);
rc = -EIO;
goto out;
}
rc = 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)) {
ecryptfs_printk(KERN_ERR, "message_len [%d]; max len is [%d]\n",
message_len, (i + key_rec->enc_key_size));
rc = -EIO;
goto out;
}
if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
ecryptfs_printk(KERN_ERR, "Encrypted key_size [%d] larger than "
"the maximum key size [%d]\n",
key_rec->enc_key_size,
ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
rc = -EIO;
goto out;
}
memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size);
out:
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)
{
u16 cipher_code = 0;
struct ecryptfs_msg_ctx *msg_ctx;
struct ecryptfs_message *msg = NULL;
char *auth_tok_sig;
char *netlink_message;
size_t netlink_message_length;
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),
&netlink_message, &netlink_message_length);
if (rc) {
ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet");
goto out;
}
rc = ecryptfs_send_message(ecryptfs_transport, netlink_message,
netlink_message_length, &msg_ctx);
if (rc) {
ecryptfs_printk(KERN_ERR, "Error sending netlink message\n");
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:
if (msg)
kfree(msg);
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 = 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");
rc = -EINVAL;
goto out;
}
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 = 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 (unlikely(data[(*packet_size)++] != 0x04)) {
printk(KERN_WARNING "Unknown version number [%d]\n",
data[(*packet_size) - 1]);
rc = -EINVAL;
goto out_free;
}
ecryptfs_cipher_code_to_string(crypt_stat->cipher,
(u16)data[(*packet_size)]);
/* 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;
}
ecryptfs_init_crypt_ctx(crypt_stat);
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 = 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 (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;
}
static int
ecryptfs_find_global_auth_tok_for_sig(
struct ecryptfs_global_auth_tok **global_auth_tok,
struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig)
{
struct ecryptfs_global_auth_tok *walker;
int rc = 0;
(*global_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) == 0) {
(*global_auth_tok) = walker;
goto out;
}
}
rc = -EINVAL;
out:
mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
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;
}
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 (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
printk(KERN_ERR "Could not find key with description: [%s]\n",
sig);
process_request_key_err(PTR_ERR(*auth_tok_key));
rc = -EINVAL;
goto out;
}
(*auth_tok) = ecryptfs_get_key_payload_data(*auth_tok_key);
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;
}
/**
* ecryptfs_find_auth_tok_for_sig
* @auth_tok: Set to the matching auth_tok; NULL if not found
* @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