1/*
2 *   fs/cifs/cifs_spnego.c -- SPNEGO upcall management for CIFS
3 *
4 *   Copyright (c) 2007 Red Hat, Inc.
5 *   Author(s): Jeff Layton (jlayton@redhat.com)
6 *
7 *   This library is free software; you can redistribute it and/or modify
8 *   it under the terms of the GNU Lesser General Public License as published
9 *   by the Free Software Foundation; either version 2.1 of the License, or
10 *   (at your option) any later version.
11 *
12 *   This library is distributed in the hope that it will be useful,
13 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
14 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
15 *   the GNU Lesser General Public License for more details.
16 *
17 *   You should have received a copy of the GNU Lesser General Public License
18 *   along with this library; if not, write to the Free Software
19 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21
22#include <linux/list.h>
23#include <linux/slab.h>
24#include <linux/string.h>
25#include <keys/user-type.h>
26#include <linux/key-type.h>
27#include <linux/inet.h>
28#include "cifsglob.h"
29#include "cifs_spnego.h"
30#include "cifs_debug.h"
31
32/* create a new cifs key */
33static int
34cifs_spnego_key_instantiate(struct key *key, const void *data, size_t datalen)
35{
36	char *payload;
37	int ret;
38
39	ret = -ENOMEM;
40	payload = kmalloc(datalen, GFP_KERNEL);
41	if (!payload)
42		goto error;
43
44	/* attach the data */
45	memcpy(payload, data, datalen);
46	key->payload.data = payload;
47	ret = 0;
48
49error:
50	return ret;
51}
52
53static void
54cifs_spnego_key_destroy(struct key *key)
55{
56	kfree(key->payload.data);
57}
58
59
60/*
61 * keytype for CIFS spnego keys
62 */
63struct key_type cifs_spnego_key_type = {
64	.name		= "cifs.spnego",
65	.instantiate	= cifs_spnego_key_instantiate,
66	.match		= user_match,
67	.destroy	= cifs_spnego_key_destroy,
68	.describe	= user_describe,
69};
70
71/* length of longest version string e.g.  strlen("ver=0xFF") */
72#define MAX_VER_STR_LEN		8
73
74/* length of longest security mechanism name, eg in future could have
75 * strlen(";sec=ntlmsspi") */
76#define MAX_MECH_STR_LEN	13
77
78/* strlen of "host=" */
79#define HOST_KEY_LEN		5
80
81/* strlen of ";ip4=" or ";ip6=" */
82#define IP_KEY_LEN		5
83
84/* strlen of ";uid=0x" */
85#define UID_KEY_LEN		7
86
87/* strlen of ";creduid=0x" */
88#define CREDUID_KEY_LEN		11
89
90/* strlen of ";user=" */
91#define USER_KEY_LEN		6
92
93/* strlen of ";pid=0x" */
94#define PID_KEY_LEN		7
95
96/* get a key struct with a SPNEGO security blob, suitable for session setup */
97struct key *
98cifs_get_spnego_key(struct cifsSesInfo *sesInfo)
99{
100	struct TCP_Server_Info *server = sesInfo->server;
101	char *description, *dp;
102	size_t desc_len;
103	struct key *spnego_key;
104	const char *hostname = server->hostname;
105
106	/* length of fields (with semicolons): ver=0xyz ip4=ipaddress
107	   host=hostname sec=mechanism uid=0xFF user=username */
108	desc_len = MAX_VER_STR_LEN +
109		   HOST_KEY_LEN + strlen(hostname) +
110		   IP_KEY_LEN + INET6_ADDRSTRLEN +
111		   MAX_MECH_STR_LEN +
112		   UID_KEY_LEN + (sizeof(uid_t) * 2) +
113		   CREDUID_KEY_LEN + (sizeof(uid_t) * 2) +
114		   USER_KEY_LEN + strlen(sesInfo->userName) +
115		   PID_KEY_LEN + (sizeof(pid_t) * 2) + 1;
116
117	spnego_key = ERR_PTR(-ENOMEM);
118	description = kzalloc(desc_len, GFP_KERNEL);
119	if (description == NULL)
120		goto out;
121
122	dp = description;
123	/* start with version and hostname portion of UNC string */
124	spnego_key = ERR_PTR(-EINVAL);
125	sprintf(dp, "ver=0x%x;host=%s;", CIFS_SPNEGO_UPCALL_VERSION,
126		hostname);
127	dp = description + strlen(description);
128
129	/* add the server address */
130	if (server->addr.sockAddr.sin_family == AF_INET)
131		sprintf(dp, "ip4=%pI4", &server->addr.sockAddr.sin_addr);
132	else if (server->addr.sockAddr.sin_family == AF_INET6)
133		sprintf(dp, "ip6=%pI6", &server->addr.sockAddr6.sin6_addr);
134	else
135		goto out;
136
137	dp = description + strlen(description);
138
139	/* for now, only sec=krb5 and sec=mskrb5 are valid */
140	if (server->sec_kerberos)
141		sprintf(dp, ";sec=krb5");
142	else if (server->sec_mskerberos)
143		sprintf(dp, ";sec=mskrb5");
144	else
145		goto out;
146
147	dp = description + strlen(description);
148	sprintf(dp, ";uid=0x%x", sesInfo->linux_uid);
149
150	dp = description + strlen(description);
151	sprintf(dp, ";creduid=0x%x", sesInfo->cred_uid);
152
153	dp = description + strlen(description);
154	sprintf(dp, ";user=%s", sesInfo->userName);
155
156	dp = description + strlen(description);
157	sprintf(dp, ";pid=0x%x", current->pid);
158
159	cFYI(1, "key description = %s", description);
160	spnego_key = request_key(&cifs_spnego_key_type, description, "");
161
162#ifdef CONFIG_CIFS_DEBUG2
163	if (cifsFYI && !IS_ERR(spnego_key)) {
164		struct cifs_spnego_msg *msg = spnego_key->payload.data;
165		cifs_dump_mem("SPNEGO reply blob:", msg->data, min(1024U,
166				msg->secblob_len + msg->sesskey_len));
167	}
168#endif /* CONFIG_CIFS_DEBUG2 */
169
170out:
171	kfree(description);
172	return spnego_key;
173}
174