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 */
33 static int
cifs_spnego_key_instantiate(struct key * key,struct key_preparsed_payload * prep)34 cifs_spnego_key_instantiate(struct key *key, struct key_preparsed_payload *prep)
35 {
36 char *payload;
37 int ret;
38
39 ret = -ENOMEM;
40 payload = kmemdup(prep->data, prep->datalen, GFP_KERNEL);
41 if (!payload)
42 goto error;
43
44 /* attach the data */
45 key->payload.data = payload;
46 ret = 0;
47
48 error:
49 return ret;
50 }
51
52 static void
cifs_spnego_key_destroy(struct key * key)53 cifs_spnego_key_destroy(struct key *key)
54 {
55 kfree(key->payload.data);
56 }
57
58
59 /*
60 * keytype for CIFS spnego keys
61 */
62 struct key_type cifs_spnego_key_type = {
63 .name = "cifs.spnego",
64 .instantiate = cifs_spnego_key_instantiate,
65 .match = user_match,
66 .destroy = cifs_spnego_key_destroy,
67 .describe = user_describe,
68 };
69
70 /* length of longest version string e.g. strlen("ver=0xFF") */
71 #define MAX_VER_STR_LEN 8
72
73 /* length of longest security mechanism name, eg in future could have
74 * strlen(";sec=ntlmsspi") */
75 #define MAX_MECH_STR_LEN 13
76
77 /* strlen of "host=" */
78 #define HOST_KEY_LEN 5
79
80 /* strlen of ";ip4=" or ";ip6=" */
81 #define IP_KEY_LEN 5
82
83 /* strlen of ";uid=0x" */
84 #define UID_KEY_LEN 7
85
86 /* strlen of ";creduid=0x" */
87 #define CREDUID_KEY_LEN 11
88
89 /* strlen of ";user=" */
90 #define USER_KEY_LEN 6
91
92 /* strlen of ";pid=0x" */
93 #define PID_KEY_LEN 7
94
95 /* get a key struct with a SPNEGO security blob, suitable for session setup */
96 struct key *
cifs_get_spnego_key(struct cifs_ses * sesInfo)97 cifs_get_spnego_key(struct cifs_ses *sesInfo)
98 {
99 struct TCP_Server_Info *server = sesInfo->server;
100 struct sockaddr_in *sa = (struct sockaddr_in *) &server->dstaddr;
101 struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *) &server->dstaddr;
102 char *description, *dp;
103 size_t desc_len;
104 struct key *spnego_key;
105 const char *hostname = server->hostname;
106
107 /* length of fields (with semicolons): ver=0xyz ip4=ipaddress
108 host=hostname sec=mechanism uid=0xFF user=username */
109 desc_len = MAX_VER_STR_LEN +
110 HOST_KEY_LEN + strlen(hostname) +
111 IP_KEY_LEN + INET6_ADDRSTRLEN +
112 MAX_MECH_STR_LEN +
113 UID_KEY_LEN + (sizeof(uid_t) * 2) +
114 CREDUID_KEY_LEN + (sizeof(uid_t) * 2) +
115 PID_KEY_LEN + (sizeof(pid_t) * 2) + 1;
116
117 if (sesInfo->user_name)
118 desc_len += USER_KEY_LEN + strlen(sesInfo->user_name);
119
120 spnego_key = ERR_PTR(-ENOMEM);
121 description = kzalloc(desc_len, GFP_KERNEL);
122 if (description == NULL)
123 goto out;
124
125 dp = description;
126 /* start with version and hostname portion of UNC string */
127 spnego_key = ERR_PTR(-EINVAL);
128 sprintf(dp, "ver=0x%x;host=%s;", CIFS_SPNEGO_UPCALL_VERSION,
129 hostname);
130 dp = description + strlen(description);
131
132 /* add the server address */
133 if (server->dstaddr.ss_family == AF_INET)
134 sprintf(dp, "ip4=%pI4", &sa->sin_addr);
135 else if (server->dstaddr.ss_family == AF_INET6)
136 sprintf(dp, "ip6=%pI6", &sa6->sin6_addr);
137 else
138 goto out;
139
140 dp = description + strlen(description);
141
142 /* for now, only sec=krb5 and sec=mskrb5 are valid */
143 if (server->sec_kerberos)
144 sprintf(dp, ";sec=krb5");
145 else if (server->sec_mskerberos)
146 sprintf(dp, ";sec=mskrb5");
147 else
148 goto out;
149
150 dp = description + strlen(description);
151 sprintf(dp, ";uid=0x%x",
152 from_kuid_munged(&init_user_ns, sesInfo->linux_uid));
153
154 dp = description + strlen(description);
155 sprintf(dp, ";creduid=0x%x",
156 from_kuid_munged(&init_user_ns, sesInfo->cred_uid));
157
158 if (sesInfo->user_name) {
159 dp = description + strlen(description);
160 sprintf(dp, ";user=%s", sesInfo->user_name);
161 }
162
163 dp = description + strlen(description);
164 sprintf(dp, ";pid=0x%x", current->pid);
165
166 cifs_dbg(FYI, "key description = %s\n", description);
167 spnego_key = request_key(&cifs_spnego_key_type, description, "");
168
169 #ifdef CONFIG_CIFS_DEBUG2
170 if (cifsFYI && !IS_ERR(spnego_key)) {
171 struct cifs_spnego_msg *msg = spnego_key->payload.data;
172 cifs_dump_mem("SPNEGO reply blob:", msg->data, min(1024U,
173 msg->secblob_len + msg->sesskey_len));
174 }
175 #endif /* CONFIG_CIFS_DEBUG2 */
176
177 out:
178 kfree(description);
179 return spnego_key;
180 }
181