1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
|
/**
* eCryptfs: Linux filesystem encryption layer
*
* Copyright (C) 2004-2006 International Business Machines Corp.
* Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
* Tyler Hicks <tyhicks@ou.edu>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 as published by the Free Software Foundation.
*
* 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 <net/sock.h>
#include <linux/hash.h>
#include <linux/random.h>
#include "ecryptfs_kernel.h"
static struct sock *ecryptfs_nl_sock;
/**
* ecryptfs_send_netlink
* @data: The data to include as the payload
* @data_len: The byte count of the data
* @msg_ctx: The netlink context that will be used to handle the
* response message
* @msg_type: The type of netlink message to send
* @msg_flags: The flags to include in the netlink header
* @daemon_pid: The process id of the daemon to send the message to
*
* Sends the data to the specified daemon pid and uses the netlink
* context element to store the data needed for validation upon
* receiving the response. The data and the netlink context can be
* null if just sending a netlink header is sufficient. Returns zero
* upon sending the message; non-zero upon error.
*/
int ecryptfs_send_netlink(char *data, int data_len,
struct ecryptfs_msg_ctx *msg_ctx, u16 msg_type,
u16 msg_flags, pid_t daemon_pid)
{
struct sk_buff *skb;
struct nlmsghdr *nlh;
struct ecryptfs_message *msg;
size_t payload_len;
int rc;
payload_len = ((data && data_len) ? (sizeof(*msg) + data_len) : 0);
skb = alloc_skb(NLMSG_SPACE(payload_len), GFP_KERNEL);
if (!skb) {
rc = -ENOMEM;
ecryptfs_printk(KERN_ERR, "Failed to allocate socket buffer\n");
goto out;
}
nlh = NLMSG_PUT(skb, daemon_pid, msg_ctx ? msg_ctx->counter : 0,
msg_type, payload_len);
nlh->nlmsg_flags = msg_flags;
if (msg_ctx && payload_len) {
msg = (struct ecryptfs_message *)NLMSG_DATA(nlh);
msg->index = msg_ctx->index;
msg->data_len = data_len;
memcpy(msg->data, data, data_len);
}
rc = netlink_unicast(ecryptfs_nl_sock, skb, daemon_pid, 0);
if (rc < 0) {
ecryptfs_printk(KERN_ERR, "Failed to send eCryptfs netlink "
"message; rc = [%d]\n", rc);
goto out;
}
rc = 0;
goto out;
nlmsg_failure:
rc = -EMSGSIZE;
kfree_skb(skb);
out:
return rc;
}
/**
* ecryptfs_process_nl_reponse
* @skb: The socket buffer containing the netlink message of state
* RESPONSE
*
* Processes a response message after sending a operation request to
* userspace. Attempts to assign the msg to a netlink context element
* at the index specified in the msg. The sk_buff and nlmsghdr must
* be validated before this function. Returns zero upon delivery to
* desired context element; non-zero upon delivery failure or error.
*/
static int ecryptfs_process_nl_response(struct sk_buff *skb)
{
struct nlmsghdr *nlh = nlmsg_hdr(skb);
struct ecryptfs_message *msg = NLMSG_DATA(nlh);
int rc;
if (skb->len - NLMSG_HDRLEN - sizeof(*msg) != msg->data_len) {
rc = -EINVAL;
ecryptfs_printk(KERN_ERR, "Received netlink message with "
"incorrectly specified data length\n");
goto out;
}
rc = ecryptfs_process_response(msg, NETLINK_CREDS(skb)->uid,
NETLINK_CREDS(skb)->pid, nlh->nlmsg_seq);
if (rc)
printk(KERN_ERR
"Error processing response message; rc = [%d]\n", rc);
out:
return rc;
}
/**
* ecryptfs_process_nl_helo
* @skb: The socket buffer containing the nlmsghdr in HELO state
*
* Gets uid and pid of the skb and adds the values to the daemon id
* hash. Returns zero after adding a new daemon id to the hash list;
* non-zero otherwise.
*/
static int ecryptfs_process_nl_helo(struct sk_buff *skb)
{
int rc;
rc = ecryptfs_process_helo(ECRYPTFS_TRANSPORT_NETLINK,
NETLINK_CREDS(skb)->uid,
NETLINK_CREDS(skb)->pid);
if (rc)
printk(KERN_WARNING "Error processing HELO; rc = [%d]\n", rc);
return rc;
}
/**
* ecryptfs_process_nl_quit
* @skb: The socket buffer containing the nlmsghdr in QUIT state
*
* Gets uid and pid of the skb and deletes the corresponding daemon
* id, if it is the registered that is requesting the
* deletion. Returns zero after deleting the desired daemon id;
* non-zero otherwise.
*/
static int ecryptfs_process_nl_quit(struct sk_buff *skb)
{
int rc;
rc = ecryptfs_process_quit(NETLINK_CREDS(skb)->uid,
NETLINK_CREDS(skb)->pid);
if (rc)
printk(KERN_WARNING
"Error processing QUIT message; rc = [%d]\n", rc);
return rc;
}
/**
* ecryptfs_receive_nl_message
*
* Callback function called by netlink system when a message arrives.
* If the message looks to be valid, then an attempt is made to assign
* it to its desired netlink context element and wake up the process
* that is waiting for a response.
*/
static void ecryptfs_receive_nl_message(struct sk_buff *skb)
{
struct nlmsghdr *nlh;
nlh = nlmsg_hdr(skb);
if (!NLMSG_OK(nlh, skb->len)) {
ecryptfs_printk(KERN_ERR, "Received corrupt netlink "
"message\n");
goto free;
}
switch (nlh->nlmsg_type) {
case ECRYPTFS_NLMSG_RESPONSE:
if (ecryptfs_process_nl_response(skb)) {
ecryptfs_printk(KERN_WARNING, "Failed to "
"deliver netlink response to "
"requesting operation\n");
}
break;
case ECRYPTFS_NLMSG_HELO:
if (ecryptfs_process_nl_helo(skb)) {
ecryptfs_printk(KERN_WARNING, "Failed to "
"fulfill HELO request\n");
}
break;
case ECRYPTFS_NLMSG_QUIT:
if (ecryptfs_process_nl_quit(skb)) {
ecryptfs_printk(KERN_WARNING, "Failed to "
"fulfill QUIT request\n");
}
break;
default:
ecryptfs_printk(KERN_WARNING, "Dropping netlink "
"message of unrecognized type [%d]\n",
nlh->nlmsg_type);
break;
}
free:
kfree_skb(skb);
}
/**
* ecryptfs_init_netlink
*
* Initializes the daemon id hash list, netlink context array, and
* necessary locks. Returns zero upon success; non-zero upon error.
*/
int ecryptfs_init_netlink(void)
{
int rc;
ecryptfs_nl_sock = netlink_kernel_create(&init_net, NETLINK_ECRYPTFS, 0,
ecryptfs_receive_nl_message,
NULL, THIS_MODULE);
if (!ecryptfs_nl_sock) {
rc = -EIO;
ecryptfs_printk(KERN_ERR, "Failed to create netlink socket\n");
goto out;
}
ecryptfs_nl_sock->sk_sndtimeo = ECRYPTFS_DEFAULT_SEND_TIMEOUT;
rc = 0;
out:
return rc;
}
/**
* ecryptfs_release_netlink
*
* Frees all memory used by the netlink context array and releases the
* netlink socket.
*/
void ecryptfs_release_netlink(void)
{
netlink_kernel_release(ecryptfs_nl_sock);
ecryptfs_nl_sock = NULL;
}
|
