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416fd2a8 | 1 | /* $OpenBSD: gss-serv-krb5.c,v 1.2 2003/11/21 11:57:03 djm Exp $ */ |
70791e56 | 2 | |
88928908 | 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" | |
88928908 | 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 | |
416fd2a8 | 42 | # include <krb5.h> |
88928908 | 43 | #else |
416fd2a8 | 44 | # ifdef HAVE_GSSAPI_KRB5 |
45 | # include <gssapi_krb5.h> | |
46 | # elif HAVE_GSSAPI_GSSAPI_KRB5 | |
47 | # include <gssapi/gssapi_krb5.h> | |
48 | # endif | |
88928908 | 49 | #endif |
50 | ||
88928908 | 51 | static krb5_context krb_context = NULL; |
52 | ||
70791e56 | 53 | /* Initialise the krb5 library, for the stuff that GSSAPI won't do */ |
88928908 | 54 | |
416fd2a8 | 55 | static int |
70791e56 | 56 | ssh_gssapi_krb5_init() |
57 | { | |
88928908 | 58 | krb5_error_code problem; |
70791e56 | 59 | |
60 | if (krb_context != NULL) | |
88928908 | 61 | return 1; |
70791e56 | 62 | |
88928908 | 63 | problem = krb5_init_context(&krb_context); |
64 | if (problem) { | |
70791e56 | 65 | logit("Cannot initialize krb5 context"); |
88928908 | 66 | return 0; |
67 | } | |
68 | krb5_init_ets(krb_context); | |
69 | ||
70791e56 | 70 | return 1; |
71 | } | |
88928908 | 72 | |
70791e56 | 73 | /* Check if this user is OK to login. This only works with krb5 - other |
88928908 | 74 | * GSSAPI mechanisms will need their own. |
75 | * Returns true if the user is OK to log in, otherwise returns 0 | |
76 | */ | |
77 | ||
78 | static int | |
70791e56 | 79 | ssh_gssapi_krb5_userok(ssh_gssapi_client *client, char *name) |
80 | { | |
88928908 | 81 | krb5_principal princ; |
82 | int retval; | |
83 | ||
84 | if (ssh_gssapi_krb5_init() == 0) | |
85 | return 0; | |
70791e56 | 86 | |
87 | if ((retval = krb5_parse_name(krb_context, client->exportedname.value, | |
88 | &princ))) { | |
89 | logit("krb5_parse_name(): %.100s", | |
90 | krb5_get_err_text(krb_context, retval)); | |
88928908 | 91 | return 0; |
92 | } | |
93 | if (krb5_kuserok(krb_context, princ, name)) { | |
94 | retval = 1; | |
70791e56 | 95 | logit("Authorized to %s, krb5 principal %s (krb5_kuserok)", |
96 | name, (char *)client->displayname.value); | |
97 | } else | |
88928908 | 98 | retval = 0; |
70791e56 | 99 | |
88928908 | 100 | krb5_free_principal(krb_context, princ); |
101 | return retval; | |
102 | } | |
103 | ||
70791e56 | 104 | |
88928908 | 105 | /* Retrieve the local username associated with a set of Kerberos |
106 | * credentials. Hopefully we can use this for the 'empty' username | |
107 | * logins discussed in the draft */ | |
108 | static int | |
109 | ssh_gssapi_krb5_localname(ssh_gssapi_client *client, char **user) { | |
110 | krb5_principal princ; | |
111 | int retval; | |
112 | ||
113 | if (ssh_gssapi_krb5_init() == 0) | |
114 | return 0; | |
115 | ||
70791e56 | 116 | if ((retval=krb5_parse_name(krb_context, client->displayname.value, |
88928908 | 117 | &princ))) { |
70791e56 | 118 | logit("krb5_parse_name(): %.100s", |
88928908 | 119 | krb5_get_err_text(krb_context,retval)); |
120 | return 0; | |
121 | } | |
122 | ||
123 | /* We've got to return a malloc'd string */ | |
124 | *user = (char *)xmalloc(256); | |
125 | if (krb5_aname_to_localname(krb_context, princ, 256, *user)) { | |
126 | xfree(*user); | |
127 | *user = NULL; | |
128 | return(0); | |
129 | } | |
130 | ||
131 | return(1); | |
132 | } | |
133 | ||
70791e56 | 134 | /* This writes out any forwarded credentials from the structure populated |
135 | * during userauth. Called after we have setuid to the user */ | |
88928908 | 136 | |
137 | static void | |
70791e56 | 138 | ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client) |
139 | { | |
88928908 | 140 | krb5_ccache ccache; |
141 | krb5_error_code problem; | |
142 | krb5_principal princ; | |
70791e56 | 143 | OM_uint32 maj_status, min_status; |
88928908 | 144 | gss_cred_id_t krb5_cred_handle; |
416fd2a8 | 145 | int len; |
70791e56 | 146 | |
147 | if (client->creds == NULL) { | |
148 | debug("No credentials stored"); | |
88928908 | 149 | return; |
150 | } | |
70791e56 | 151 | |
88928908 | 152 | if (ssh_gssapi_krb5_init() == 0) |
153 | return; | |
154 | ||
70791e56 | 155 | #ifdef HEIMDAL |
156 | if ((problem = krb5_cc_gen_new(krb_context, &krb5_fcc_ops, &ccache))) { | |
157 | logit("krb5_cc_gen_new(): %.100s", | |
158 | krb5_get_err_text(krb_context, problem)); | |
88928908 | 159 | return; |
160 | } | |
70791e56 | 161 | #else |
162 | { | |
163 | int tmpfd; | |
164 | char ccname[40]; | |
416fd2a8 | 165 | |
166 | snprintf(ccname, sizeof(ccname), | |
70791e56 | 167 | "FILE:/tmp/krb5cc_%d_XXXXXX", geteuid()); |
416fd2a8 | 168 | |
70791e56 | 169 | if ((tmpfd = mkstemp(ccname + strlen("FILE:"))) == -1) { |
170 | logit("mkstemp(): %.100s", strerror(errno)); | |
171 | problem = errno; | |
172 | return; | |
173 | } | |
174 | if (fchmod(tmpfd, S_IRUSR | S_IWUSR) == -1) { | |
175 | logit("fchmod(): %.100s", strerror(errno)); | |
176 | close(tmpfd); | |
177 | problem = errno; | |
178 | return; | |
179 | } | |
180 | close(tmpfd); | |
181 | if ((problem = krb5_cc_resolve(krb_context, ccname, &ccache))) { | |
182 | logit("krb5_cc_resolve(): %.100s", | |
183 | krb5_get_err_text(krb_context, problem)); | |
184 | return; | |
185 | } | |
186 | } | |
187 | #endif /* #ifdef HEIMDAL */ | |
188 | ||
416fd2a8 | 189 | if ((problem = krb5_parse_name(krb_context, |
70791e56 | 190 | client->exportedname.value, &princ))) { |
191 | logit("krb5_parse_name(): %.100s", | |
192 | krb5_get_err_text(krb_context, problem)); | |
193 | krb5_cc_destroy(krb_context, ccache); | |
194 | return; | |
195 | } | |
196 | ||
88928908 | 197 | if ((problem = krb5_cc_initialize(krb_context, ccache, princ))) { |
70791e56 | 198 | logit("krb5_cc_initialize(): %.100s", |
199 | krb5_get_err_text(krb_context, problem)); | |
200 | krb5_free_principal(krb_context, princ); | |
201 | krb5_cc_destroy(krb_context, ccache); | |
88928908 | 202 | return; |
203 | } | |
70791e56 | 204 | |
205 | krb5_free_principal(krb_context, princ); | |
88928908 | 206 | |
207 | #ifdef MECHGLUE | |
208 | krb5_cred_handle = | |
209 | __gss_get_mechanism_cred(client->creds, | |
210 | &(gssapi_kerberos_mech.oid)); | |
211 | #else | |
212 | krb5_cred_handle = client->creds; | |
213 | #endif | |
214 | ||
215 | if ((maj_status = gss_krb5_copy_ccache(&min_status, | |
70791e56 | 216 | krb5_cred_handle, ccache))) { |
217 | logit("gss_krb5_copy_ccache() failed"); | |
218 | krb5_cc_destroy(krb_context, ccache); | |
88928908 | 219 | return; |
220 | } | |
70791e56 | 221 | |
222 | client->store.filename = xstrdup(krb5_cc_get_name(krb_context, ccache)); | |
223 | client->store.envvar = "KRB5CCNAME"; | |
416fd2a8 | 224 | len = strlen(client->store.filename) + 6; |
225 | client->store.envval = xmalloc(len); | |
226 | snprintf(client->store.envval, len, "FILE:%s", client->store.filename); | |
88928908 | 227 | |
228 | #ifdef USE_PAM | |
70791e56 | 229 | if (options.use_pam) |
416fd2a8 | 230 | do_pam_putenv(client->store.envvar, client->store.envval); |
88928908 | 231 | #endif |
232 | ||
70791e56 | 233 | krb5_cc_close(krb_context, ccache); |
88928908 | 234 | |
235 | return; | |
236 | } | |
237 | ||
70791e56 | 238 | ssh_gssapi_mech gssapi_kerberos_mech = { |
239 | "toWM5Slw5Ew8Mqkay+al2g==", | |
240 | "Kerberos", | |
241 | {9, "\x2A\x86\x48\x86\xF7\x12\x01\x02\x02"}, | |
242 | NULL, | |
243 | &ssh_gssapi_krb5_userok, | |
244 | &ssh_gssapi_krb5_localname, | |
245 | &ssh_gssapi_krb5_storecreds | |
246 | }; | |
247 | ||
248 | ssh_gssapi_mech gssapi_kerberos_mech_old = { | |
249 | "Se3H81ismmOC3OE+FwYCiQ==", | |
250 | "Kerberos", | |
251 | {9, "\x2A\x86\x48\x86\xF7\x12\x01\x02\x02"}, | |
252 | &ssh_gssapi_krb5_init, | |
253 | &ssh_gssapi_krb5_userok, | |
254 | &ssh_gssapi_krb5_localname, | |
255 | &ssh_gssapi_krb5_storecreds | |
256 | }; | |
257 | ||
88928908 | 258 | #endif /* KRB5 */ |
259 | ||
260 | #endif /* GSSAPI */ |