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9cb1827b | 1 | /* $OpenBSD: gss-serv-krb5.c,v 1.1 2003/08/22 10:56:09 markus Exp $ */ |
0fff78ff | 2 | |
3 | /* | |
4 | * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved. | |
5 | * | |
6 | * Redistribution and use in source and binary forms, with or without | |
7 | * modification, are permitted provided that the following conditions | |
8 | * are met: | |
9 | * 1. Redistributions of source code must retain the above copyright | |
10 | * notice, this list of conditions and the following disclaimer. | |
11 | * 2. Redistributions in binary form must reproduce the above copyright | |
12 | * notice, this list of conditions and the following disclaimer in the | |
13 | * documentation and/or other materials provided with the distribution. | |
14 | * | |
15 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR `AS IS'' AND ANY EXPRESS OR | |
16 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
17 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
18 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
19 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
20 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
21 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
22 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
23 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
24 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
25 | */ | |
26 | ||
27 | #include "includes.h" | |
28 | ||
29 | #ifdef GSSAPI | |
30 | #ifdef KRB5 | |
31 | ||
32 | #include "auth.h" | |
33 | #include "xmalloc.h" | |
34 | #include "log.h" | |
35 | #include "servconf.h" | |
36 | ||
37 | #include "ssh-gss.h" | |
38 | ||
39 | extern ServerOptions options; | |
40 | ||
41 | #ifdef HEIMDAL | |
42 | #include <krb5.h> | |
43 | #else | |
44 | #include <gssapi_krb5.h> | |
45 | #endif | |
46 | ||
47 | static krb5_context krb_context = NULL; | |
48 | ||
49 | /* Initialise the krb5 library, for the stuff that GSSAPI won't do */ | |
50 | ||
9cb1827b | 51 | static int |
0fff78ff | 52 | ssh_gssapi_krb5_init() |
53 | { | |
54 | krb5_error_code problem; | |
55 | ||
56 | if (krb_context != NULL) | |
57 | return 1; | |
58 | ||
59 | problem = krb5_init_context(&krb_context); | |
60 | if (problem) { | |
61 | logit("Cannot initialize krb5 context"); | |
62 | return 0; | |
63 | } | |
64 | krb5_init_ets(krb_context); | |
65 | ||
66 | return 1; | |
67 | } | |
68 | ||
69 | /* Check if this user is OK to login. This only works with krb5 - other | |
70 | * GSSAPI mechanisms will need their own. | |
71 | * Returns true if the user is OK to log in, otherwise returns 0 | |
72 | */ | |
73 | ||
74 | static int | |
75 | ssh_gssapi_krb5_userok(ssh_gssapi_client *client, char *name) | |
76 | { | |
77 | krb5_principal princ; | |
78 | int retval; | |
79 | ||
80 | if (ssh_gssapi_krb5_init() == 0) | |
81 | return 0; | |
82 | ||
83 | if ((retval = krb5_parse_name(krb_context, client->exportedname.value, | |
84 | &princ))) { | |
85 | logit("krb5_parse_name(): %.100s", | |
86 | krb5_get_err_text(krb_context, retval)); | |
87 | return 0; | |
88 | } | |
89 | if (krb5_kuserok(krb_context, princ, name)) { | |
90 | retval = 1; | |
91 | logit("Authorized to %s, krb5 principal %s (krb5_kuserok)", | |
92 | name, (char *)client->displayname.value); | |
93 | } else | |
94 | retval = 0; | |
95 | ||
96 | krb5_free_principal(krb_context, princ); | |
97 | return retval; | |
98 | } | |
99 | ||
100 | ||
101 | /* This writes out any forwarded credentials from the structure populated | |
102 | * during userauth. Called after we have setuid to the user */ | |
103 | ||
104 | static void | |
105 | ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client) | |
106 | { | |
107 | krb5_ccache ccache; | |
108 | krb5_error_code problem; | |
109 | krb5_principal princ; | |
110 | OM_uint32 maj_status, min_status; | |
111 | ||
112 | if (client->creds == NULL) { | |
113 | debug("No credentials stored"); | |
114 | return; | |
115 | } | |
116 | ||
117 | if (ssh_gssapi_krb5_init() == 0) | |
118 | return; | |
119 | ||
120 | #ifdef HEIMDAL | |
121 | if ((problem = krb5_cc_gen_new(krb_context, &krb5_fcc_ops, &ccache))) { | |
122 | logit("krb5_cc_gen_new(): %.100s", | |
123 | krb5_get_err_text(krb_context, problem)); | |
124 | return; | |
125 | } | |
126 | #else | |
127 | { | |
128 | int tmpfd; | |
129 | char ccname[40]; | |
9cb1827b | 130 | |
131 | snprintf(ccname, sizeof(ccname), | |
0fff78ff | 132 | "FILE:/tmp/krb5cc_%d_XXXXXX", geteuid()); |
9cb1827b | 133 | |
0fff78ff | 134 | if ((tmpfd = mkstemp(ccname + strlen("FILE:"))) == -1) { |
135 | logit("mkstemp(): %.100s", strerror(errno)); | |
136 | problem = errno; | |
137 | return; | |
138 | } | |
139 | if (fchmod(tmpfd, S_IRUSR | S_IWUSR) == -1) { | |
140 | logit("fchmod(): %.100s", strerror(errno)); | |
141 | close(tmpfd); | |
142 | problem = errno; | |
143 | return; | |
144 | } | |
145 | close(tmpfd); | |
146 | if ((problem = krb5_cc_resolve(krb_context, ccname, &ccache))) { | |
147 | logit("krb5_cc_resolve(): %.100s", | |
148 | krb5_get_err_text(krb_context, problem)); | |
149 | return; | |
150 | } | |
151 | } | |
152 | #endif /* #ifdef HEIMDAL */ | |
153 | ||
9cb1827b | 154 | if ((problem = krb5_parse_name(krb_context, |
0fff78ff | 155 | client->exportedname.value, &princ))) { |
156 | logit("krb5_parse_name(): %.100s", | |
157 | krb5_get_err_text(krb_context, problem)); | |
158 | krb5_cc_destroy(krb_context, ccache); | |
159 | return; | |
160 | } | |
161 | ||
162 | if ((problem = krb5_cc_initialize(krb_context, ccache, princ))) { | |
163 | logit("krb5_cc_initialize(): %.100s", | |
164 | krb5_get_err_text(krb_context, problem)); | |
165 | krb5_free_principal(krb_context, princ); | |
166 | krb5_cc_destroy(krb_context, ccache); | |
167 | return; | |
168 | } | |
169 | ||
170 | krb5_free_principal(krb_context, princ); | |
171 | ||
9cb1827b | 172 | if ((maj_status = gss_krb5_copy_ccache(&min_status, |
0fff78ff | 173 | client->creds, ccache))) { |
174 | logit("gss_krb5_copy_ccache() failed"); | |
175 | krb5_cc_destroy(krb_context, ccache); | |
176 | return; | |
177 | } | |
178 | ||
179 | client->store.filename = xstrdup(krb5_cc_get_name(krb_context, ccache)); | |
180 | client->store.envvar = "KRB5CCNAME"; | |
181 | client->store.envval = xstrdup(client->store.filename); | |
182 | ||
183 | #ifdef USE_PAM | |
184 | if (options.use_pam) | |
185 | do_pam_putenv(client->store.envvar,client->store.envval); | |
186 | #endif | |
187 | ||
188 | krb5_cc_close(krb_context, ccache); | |
189 | ||
190 | return; | |
191 | } | |
192 | ||
193 | ssh_gssapi_mech gssapi_kerberos_mech = { | |
194 | "toWM5Slw5Ew8Mqkay+al2g==", | |
195 | "Kerberos", | |
196 | {9, "\x2A\x86\x48\x86\xF7\x12\x01\x02\x02"}, | |
197 | NULL, | |
198 | &ssh_gssapi_krb5_userok, | |
199 | NULL, | |
200 | &ssh_gssapi_krb5_storecreds | |
201 | }; | |
202 | ||
203 | #endif /* KRB5 */ | |
204 | ||
205 | #endif /* GSSAPI */ |