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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 | |
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 | |
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 * | |
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 | } |