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[0] = 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[0]);
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 .destroy = cifs_spnego_key_destroy,
66 .describe = user_describe,
67 };
68
69 /* length of longest version string e.g. strlen("ver=0xFF") */
70 #define MAX_VER_STR_LEN 8
71
72 /* length of longest security mechanism name, eg in future could have
73 * strlen(";sec=ntlmsspi") */
74 #define MAX_MECH_STR_LEN 13
75
76 /* strlen of "host=" */
77 #define HOST_KEY_LEN 5
78
79 /* strlen of ";ip4=" or ";ip6=" */
80 #define IP_KEY_LEN 5
81
82 /* strlen of ";uid=0x" */
83 #define UID_KEY_LEN 7
84
85 /* strlen of ";creduid=0x" */
86 #define CREDUID_KEY_LEN 11
87
88 /* strlen of ";user=" */
89 #define USER_KEY_LEN 6
90
91 /* strlen of ";pid=0x" */
92 #define PID_KEY_LEN 7
93
94 /* get a key struct with a SPNEGO security blob, suitable for session setup */
95 struct key *
cifs_get_spnego_key(struct cifs_ses * sesInfo)96 cifs_get_spnego_key(struct cifs_ses *sesInfo)
97 {
98 struct TCP_Server_Info *server = sesInfo->server;
99 struct sockaddr_in *sa = (struct sockaddr_in *) &server->dstaddr;
100 struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *) &server->dstaddr;
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 PID_KEY_LEN + (sizeof(pid_t) * 2) + 1;
115
116 if (sesInfo->user_name)
117 desc_len += USER_KEY_LEN + strlen(sesInfo->user_name);
118
119 spnego_key = ERR_PTR(-ENOMEM);
120 description = kzalloc(desc_len, GFP_KERNEL);
121 if (description == NULL)
122 goto out;
123
124 dp = description;
125 /* start with version and hostname portion of UNC string */
126 spnego_key = ERR_PTR(-EINVAL);
127 sprintf(dp, "ver=0x%x;host=%s;", CIFS_SPNEGO_UPCALL_VERSION,
128 hostname);
129 dp = description + strlen(description);
130
131 /* add the server address */
132 if (server->dstaddr.ss_family == AF_INET)
133 sprintf(dp, "ip4=%pI4", &sa->sin_addr);
134 else if (server->dstaddr.ss_family == AF_INET6)
135 sprintf(dp, "ip6=%pI6", &sa6->sin6_addr);
136 else
137 goto out;
138
139 dp = description + strlen(description);
140
141 /* for now, only sec=krb5 and sec=mskrb5 are valid */
142 if (server->sec_kerberos)
143 sprintf(dp, ";sec=krb5");
144 else if (server->sec_mskerberos)
145 sprintf(dp, ";sec=mskrb5");
146 else {
147 cifs_dbg(VFS, "unknown or missing server auth type, use krb5\n");
148 sprintf(dp, ";sec=krb5");
149 }
150
151 dp = description + strlen(description);
152 sprintf(dp, ";uid=0x%x",
153 from_kuid_munged(&init_user_ns, sesInfo->linux_uid));
154
155 dp = description + strlen(description);
156 sprintf(dp, ";creduid=0x%x",
157 from_kuid_munged(&init_user_ns, sesInfo->cred_uid));
158
159 if (sesInfo->user_name) {
160 dp = description + strlen(description);
161 sprintf(dp, ";user=%s", sesInfo->user_name);
162 }
163
164 dp = description + strlen(description);
165 sprintf(dp, ";pid=0x%x", current->pid);
166
167 cifs_dbg(FYI, "key description = %s\n", description);
168 spnego_key = request_key(&cifs_spnego_key_type, description, "");
169
170 #ifdef CONFIG_CIFS_DEBUG2
171 if (cifsFYI && !IS_ERR(spnego_key)) {
172 struct cifs_spnego_msg *msg = spnego_key->payload.data[0];
173 cifs_dump_mem("SPNEGO reply blob:", msg->data, min(1024U,
174 msg->secblob_len + msg->sesskey_len));
175 }
176 #endif /* CONFIG_CIFS_DEBUG2 */
177
178 out:
179 kfree(description);
180 return spnego_key;
181 }
182