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08822d99 | 1 | /* $OpenBSD: gss-serv-krb5.c,v 1.4 2005/10/13 19:08:08 stevesk Exp $ */ |
7cac2b65 | 2 | |
f4b9ce42 | 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" | |
f4b9ce42 | 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 | |
540d72c3 | 42 | # include <krb5.h> |
48a25c13 | 43 | #elif !defined(MECHGLUE) |
fe4ad273 | 44 | # ifdef HAVE_GSSAPI_KRB5_H |
540d72c3 | 45 | # include <gssapi_krb5.h> |
fe4ad273 | 46 | # elif HAVE_GSSAPI_GSSAPI_KRB5_H |
540d72c3 | 47 | # include <gssapi/gssapi_krb5.h> |
48 | # endif | |
f4b9ce42 | 49 | #endif |
50 | ||
51 | static krb5_context krb_context = NULL; | |
83059c7b | 52 | static int ssh_gssapi_krb5_init(); |
53 | static int ssh_gssapi_krb5_userok(ssh_gssapi_client *client, char *name); | |
54 | static int ssh_gssapi_krb5_localname(ssh_gssapi_client *client, char **user); | |
55 | static void ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client); | |
56 | ||
57 | ssh_gssapi_mech gssapi_kerberos_mech = { | |
58 | "toWM5Slw5Ew8Mqkay+al2g==", | |
59 | "Kerberos", | |
60 | {9, "\x2A\x86\x48\x86\xF7\x12\x01\x02\x02"}, | |
61 | NULL, | |
62 | &ssh_gssapi_krb5_userok, | |
63 | &ssh_gssapi_krb5_localname, | |
64 | &ssh_gssapi_krb5_storecreds | |
65 | }; | |
66 | ||
7cac2b65 | 67 | /* Initialise the krb5 library, for the stuff that GSSAPI won't do */ |
f4b9ce42 | 68 | |
540d72c3 | 69 | static int |
7e82606e | 70 | ssh_gssapi_krb5_init(void) |
7cac2b65 | 71 | { |
f4b9ce42 | 72 | krb5_error_code problem; |
7cac2b65 | 73 | |
74 | if (krb_context != NULL) | |
f4b9ce42 | 75 | return 1; |
7cac2b65 | 76 | |
f4b9ce42 | 77 | problem = krb5_init_context(&krb_context); |
78 | if (problem) { | |
7cac2b65 | 79 | logit("Cannot initialize krb5 context"); |
f4b9ce42 | 80 | return 0; |
81 | } | |
f4b9ce42 | 82 | |
7cac2b65 | 83 | return 1; |
84 | } | |
f4b9ce42 | 85 | |
7cac2b65 | 86 | /* Check if this user is OK to login. This only works with krb5 - other |
f4b9ce42 | 87 | * GSSAPI mechanisms will need their own. |
88 | * Returns true if the user is OK to log in, otherwise returns 0 | |
89 | */ | |
90 | ||
91 | static int | |
7cac2b65 | 92 | ssh_gssapi_krb5_userok(ssh_gssapi_client *client, char *name) |
93 | { | |
f4b9ce42 | 94 | krb5_principal princ; |
95 | int retval; | |
96 | ||
97 | if (ssh_gssapi_krb5_init() == 0) | |
98 | return 0; | |
7cac2b65 | 99 | |
100 | if ((retval = krb5_parse_name(krb_context, client->exportedname.value, | |
101 | &princ))) { | |
102 | logit("krb5_parse_name(): %.100s", | |
103 | krb5_get_err_text(krb_context, retval)); | |
f4b9ce42 | 104 | return 0; |
105 | } | |
106 | if (krb5_kuserok(krb_context, princ, name)) { | |
107 | retval = 1; | |
7cac2b65 | 108 | logit("Authorized to %s, krb5 principal %s (krb5_kuserok)", |
109 | name, (char *)client->displayname.value); | |
110 | } else | |
f4b9ce42 | 111 | retval = 0; |
7cac2b65 | 112 | |
f4b9ce42 | 113 | krb5_free_principal(krb_context, princ); |
114 | return retval; | |
115 | } | |
116 | ||
7cac2b65 | 117 | |
f4b9ce42 | 118 | /* Retrieve the local username associated with a set of Kerberos |
119 | * credentials. Hopefully we can use this for the 'empty' username | |
120 | * logins discussed in the draft */ | |
121 | static int | |
122 | ssh_gssapi_krb5_localname(ssh_gssapi_client *client, char **user) { | |
123 | krb5_principal princ; | |
124 | int retval; | |
125 | ||
126 | if (ssh_gssapi_krb5_init() == 0) | |
127 | return 0; | |
128 | ||
7cac2b65 | 129 | if ((retval=krb5_parse_name(krb_context, client->displayname.value, |
f4b9ce42 | 130 | &princ))) { |
7cac2b65 | 131 | logit("krb5_parse_name(): %.100s", |
f4b9ce42 | 132 | krb5_get_err_text(krb_context,retval)); |
133 | return 0; | |
134 | } | |
135 | ||
136 | /* We've got to return a malloc'd string */ | |
137 | *user = (char *)xmalloc(256); | |
138 | if (krb5_aname_to_localname(krb_context, princ, 256, *user)) { | |
139 | xfree(*user); | |
140 | *user = NULL; | |
141 | return(0); | |
142 | } | |
143 | ||
144 | return(1); | |
145 | } | |
146 | ||
7cac2b65 | 147 | /* This writes out any forwarded credentials from the structure populated |
148 | * during userauth. Called after we have setuid to the user */ | |
f4b9ce42 | 149 | |
150 | static void | |
7cac2b65 | 151 | ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client) |
152 | { | |
f4b9ce42 | 153 | krb5_ccache ccache; |
154 | krb5_error_code problem; | |
155 | krb5_principal princ; | |
7cac2b65 | 156 | OM_uint32 maj_status, min_status; |
81d08144 | 157 | gss_cred_id_t krb5_cred_handle; |
540d72c3 | 158 | int len; |
7cac2b65 | 159 | |
160 | if (client->creds == NULL) { | |
161 | debug("No credentials stored"); | |
f4b9ce42 | 162 | return; |
163 | } | |
7cac2b65 | 164 | |
f4b9ce42 | 165 | if (ssh_gssapi_krb5_init() == 0) |
166 | return; | |
167 | ||
7cac2b65 | 168 | #ifdef HEIMDAL |
169 | if ((problem = krb5_cc_gen_new(krb_context, &krb5_fcc_ops, &ccache))) { | |
170 | logit("krb5_cc_gen_new(): %.100s", | |
171 | krb5_get_err_text(krb_context, problem)); | |
f4b9ce42 | 172 | return; |
173 | } | |
7cac2b65 | 174 | #else |
2ce0bfe4 | 175 | if ((problem = ssh_krb5_cc_gen(krb_context, &ccache))) { |
176 | logit("ssh_krb5_cc_gen(): %.100s", | |
177 | krb5_get_err_text(krb_context, problem)); | |
178 | return; | |
7cac2b65 | 179 | } |
180 | #endif /* #ifdef HEIMDAL */ | |
181 | ||
540d72c3 | 182 | if ((problem = krb5_parse_name(krb_context, |
7cac2b65 | 183 | client->exportedname.value, &princ))) { |
184 | logit("krb5_parse_name(): %.100s", | |
185 | krb5_get_err_text(krb_context, problem)); | |
186 | krb5_cc_destroy(krb_context, ccache); | |
187 | return; | |
188 | } | |
189 | ||
f4b9ce42 | 190 | if ((problem = krb5_cc_initialize(krb_context, ccache, princ))) { |
7cac2b65 | 191 | logit("krb5_cc_initialize(): %.100s", |
192 | krb5_get_err_text(krb_context, problem)); | |
193 | krb5_free_principal(krb_context, princ); | |
194 | krb5_cc_destroy(krb_context, ccache); | |
f4b9ce42 | 195 | return; |
196 | } | |
7cac2b65 | 197 | |
198 | krb5_free_principal(krb_context, princ); | |
f4b9ce42 | 199 | |
81d08144 | 200 | #ifdef MECHGLUE |
201 | krb5_cred_handle = | |
202 | __gss_get_mechanism_cred(client->creds, | |
203 | &(gssapi_kerberos_mech.oid)); | |
204 | #else | |
2af4b8d5 | 205 | krb5_cred_handle = client->creds; |
81d08144 | 206 | #endif |
207 | ||
f4b9ce42 | 208 | if ((maj_status = gss_krb5_copy_ccache(&min_status, |
7cac2b65 | 209 | krb5_cred_handle, ccache))) { |
210 | logit("gss_krb5_copy_ccache() failed"); | |
211 | krb5_cc_destroy(krb_context, ccache); | |
f4b9ce42 | 212 | return; |
213 | } | |
7cac2b65 | 214 | |
215 | client->store.filename = xstrdup(krb5_cc_get_name(krb_context, ccache)); | |
216 | client->store.envvar = "KRB5CCNAME"; | |
540d72c3 | 217 | len = strlen(client->store.filename) + 6; |
218 | client->store.envval = xmalloc(len); | |
219 | snprintf(client->store.envval, len, "FILE:%s", client->store.filename); | |
f4b9ce42 | 220 | |
221 | #ifdef USE_PAM | |
7cac2b65 | 222 | if (options.use_pam) |
540d72c3 | 223 | do_pam_putenv(client->store.envvar, client->store.envval); |
f4b9ce42 | 224 | #endif |
225 | ||
7cac2b65 | 226 | krb5_cc_close(krb_context, ccache); |
f4b9ce42 | 227 | |
228 | return; | |
229 | } | |
230 | ||
f4b9ce42 | 231 | #endif /* KRB5 */ |
232 | ||
233 | #endif /* GSSAPI */ |