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1 | /* $OpenBSD: auth-krb5.c,v 1.19 2006/08/03 03:34:41 deraadt Exp $ */ | |
2 | /* | |
3 | * Kerberos v5 authentication and ticket-passing routines. | |
4 | * | |
5 | * $FreeBSD: src/crypto/openssh/auth-krb5.c,v 1.6 2001/02/13 16:58:04 assar Exp $ | |
6 | */ | |
7 | /* | |
8 | * Copyright (c) 2002 Daniel Kouril. All rights reserved. | |
9 | * | |
10 | * Redistribution and use in source and binary forms, with or without | |
11 | * modification, are permitted provided that the following conditions | |
12 | * are met: | |
13 | * 1. Redistributions of source code must retain the above copyright | |
14 | * notice, this list of conditions and the following disclaimer. | |
15 | * 2. Redistributions in binary form must reproduce the above copyright | |
16 | * notice, this list of conditions and the following disclaimer in the | |
17 | * documentation and/or other materials provided with the distribution. | |
18 | * | |
19 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
20 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
21 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
22 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
23 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
24 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
25 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
26 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
27 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
28 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
29 | */ | |
30 | ||
31 | #include "includes.h" | |
32 | ||
33 | #include <sys/types.h> | |
34 | #include <pwd.h> | |
35 | #include <stdarg.h> | |
36 | ||
37 | #include "xmalloc.h" | |
38 | #include "ssh.h" | |
39 | #include "ssh1.h" | |
40 | #include "packet.h" | |
41 | #include "log.h" | |
42 | #include "buffer.h" | |
43 | #include "servconf.h" | |
44 | #include "uidswap.h" | |
45 | #include "key.h" | |
46 | #include "hostfile.h" | |
47 | #include "auth.h" | |
48 | ||
49 | #ifdef KRB5 | |
50 | #include <errno.h> | |
51 | #include <unistd.h> | |
52 | #include <string.h> | |
53 | #include <krb5.h> | |
54 | ||
55 | extern ServerOptions options; | |
56 | ||
57 | static int | |
58 | krb5_init(void *context) | |
59 | { | |
60 | Authctxt *authctxt = (Authctxt *)context; | |
61 | krb5_error_code problem; | |
62 | ||
63 | if (authctxt->krb5_ctx == NULL) { | |
64 | problem = krb5_init_context(&authctxt->krb5_ctx); | |
65 | if (problem) | |
66 | return (problem); | |
67 | } | |
68 | return (0); | |
69 | } | |
70 | ||
71 | int | |
72 | auth_krb5_password(Authctxt *authctxt, const char *password) | |
73 | { | |
74 | #ifndef HEIMDAL | |
75 | krb5_creds creds; | |
76 | krb5_principal server; | |
77 | #endif | |
78 | krb5_error_code problem; | |
79 | krb5_ccache ccache = NULL; | |
80 | int len; | |
81 | char *client, *platform_client; | |
82 | ||
83 | /* get platform-specific kerberos client principal name (if it exists) */ | |
84 | platform_client = platform_krb5_get_principal_name(authctxt->pw->pw_name); | |
85 | client = platform_client ? platform_client : authctxt->pw->pw_name; | |
86 | ||
87 | temporarily_use_uid(authctxt->pw); | |
88 | ||
89 | problem = krb5_init(authctxt); | |
90 | if (problem) | |
91 | goto out; | |
92 | ||
93 | problem = krb5_parse_name(authctxt->krb5_ctx, client, | |
94 | &authctxt->krb5_user); | |
95 | if (problem) | |
96 | goto out; | |
97 | ||
98 | #ifdef HEIMDAL | |
99 | problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_mcc_ops, &ccache); | |
100 | if (problem) | |
101 | goto out; | |
102 | ||
103 | problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache, | |
104 | authctxt->krb5_user); | |
105 | if (problem) | |
106 | goto out; | |
107 | ||
108 | restore_uid(); | |
109 | ||
110 | problem = krb5_verify_user(authctxt->krb5_ctx, authctxt->krb5_user, | |
111 | ccache, password, 1, NULL); | |
112 | ||
113 | temporarily_use_uid(authctxt->pw); | |
114 | ||
115 | if (problem) | |
116 | goto out; | |
117 | ||
118 | problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_fcc_ops, | |
119 | &authctxt->krb5_fwd_ccache); | |
120 | if (problem) | |
121 | goto out; | |
122 | ||
123 | problem = krb5_cc_copy_cache(authctxt->krb5_ctx, ccache, | |
124 | authctxt->krb5_fwd_ccache); | |
125 | krb5_cc_destroy(authctxt->krb5_ctx, ccache); | |
126 | ccache = NULL; | |
127 | if (problem) | |
128 | goto out; | |
129 | ||
130 | #else | |
131 | problem = krb5_get_init_creds_password(authctxt->krb5_ctx, &creds, | |
132 | authctxt->krb5_user, (char *)password, NULL, NULL, 0, NULL, NULL); | |
133 | if (problem) | |
134 | goto out; | |
135 | ||
136 | problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL, | |
137 | KRB5_NT_SRV_HST, &server); | |
138 | if (problem) | |
139 | goto out; | |
140 | ||
141 | restore_uid(); | |
142 | problem = krb5_verify_init_creds(authctxt->krb5_ctx, &creds, server, | |
143 | NULL, NULL, NULL); | |
144 | krb5_free_principal(authctxt->krb5_ctx, server); | |
145 | temporarily_use_uid(authctxt->pw); | |
146 | if (problem) | |
147 | goto out; | |
148 | ||
149 | if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user, client)) { | |
150 | problem = -1; | |
151 | goto out; | |
152 | } | |
153 | ||
154 | problem = ssh_krb5_cc_gen(authctxt->krb5_ctx, &authctxt->krb5_fwd_ccache); | |
155 | if (problem) | |
156 | goto out; | |
157 | ||
158 | problem = krb5_cc_initialize(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache, | |
159 | authctxt->krb5_user); | |
160 | if (problem) | |
161 | goto out; | |
162 | ||
163 | problem= krb5_cc_store_cred(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache, | |
164 | &creds); | |
165 | if (problem) | |
166 | goto out; | |
167 | #endif | |
168 | ||
169 | authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache); | |
170 | ||
171 | len = strlen(authctxt->krb5_ticket_file) + 6; | |
172 | authctxt->krb5_ccname = xmalloc(len); | |
173 | snprintf(authctxt->krb5_ccname, len, "FILE:%s", | |
174 | authctxt->krb5_ticket_file); | |
175 | ||
176 | #ifdef USE_PAM | |
177 | if (options.use_pam) | |
178 | do_pam_putenv("KRB5CCNAME", authctxt->krb5_ccname); | |
179 | #endif | |
180 | ||
181 | out: | |
182 | restore_uid(); | |
183 | ||
184 | if (platform_client != NULL) | |
185 | xfree(platform_client); | |
186 | ||
187 | if (problem) { | |
188 | if (ccache) | |
189 | krb5_cc_destroy(authctxt->krb5_ctx, ccache); | |
190 | ||
191 | if (authctxt->krb5_ctx != NULL && problem!=-1) | |
192 | debug("Kerberos password authentication failed: %s", | |
193 | krb5_get_err_text(authctxt->krb5_ctx, problem)); | |
194 | else | |
195 | debug("Kerberos password authentication failed: %d", | |
196 | problem); | |
197 | ||
198 | krb5_cleanup_proc(authctxt); | |
199 | ||
200 | if (options.kerberos_or_local_passwd) | |
201 | return (-1); | |
202 | else | |
203 | return (0); | |
204 | } | |
205 | return (authctxt->valid ? 1 : 0); | |
206 | } | |
207 | ||
208 | void | |
209 | krb5_cleanup_proc(Authctxt *authctxt) | |
210 | { | |
211 | debug("krb5_cleanup_proc called"); | |
212 | if (authctxt->krb5_fwd_ccache) { | |
213 | krb5_cc_destroy(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache); | |
214 | authctxt->krb5_fwd_ccache = NULL; | |
215 | } | |
216 | if (authctxt->krb5_user) { | |
217 | krb5_free_principal(authctxt->krb5_ctx, authctxt->krb5_user); | |
218 | authctxt->krb5_user = NULL; | |
219 | } | |
220 | if (authctxt->krb5_ctx) { | |
221 | krb5_free_context(authctxt->krb5_ctx); | |
222 | authctxt->krb5_ctx = NULL; | |
223 | } | |
224 | } | |
225 | ||
226 | #ifndef HEIMDAL | |
227 | krb5_error_code | |
228 | ssh_krb5_cc_gen(krb5_context ctx, krb5_ccache *ccache) { | |
229 | int tmpfd, ret; | |
230 | char ccname[40]; | |
231 | mode_t old_umask; | |
232 | ||
233 | ret = snprintf(ccname, sizeof(ccname), | |
234 | "FILE:/tmp/krb5cc_%d_XXXXXXXXXX", geteuid()); | |
235 | if (ret < 0 || (size_t)ret >= sizeof(ccname)) | |
236 | return ENOMEM; | |
237 | ||
238 | old_umask = umask(0177); | |
239 | tmpfd = mkstemp(ccname + strlen("FILE:")); | |
240 | umask(old_umask); | |
241 | if (tmpfd == -1) { | |
242 | logit("mkstemp(): %.100s", strerror(errno)); | |
243 | return errno; | |
244 | } | |
245 | ||
246 | if (fchmod(tmpfd,S_IRUSR | S_IWUSR) == -1) { | |
247 | logit("fchmod(): %.100s", strerror(errno)); | |
248 | close(tmpfd); | |
249 | return errno; | |
250 | } | |
251 | close(tmpfd); | |
252 | ||
253 | return (krb5_cc_resolve(ctx, ccname, ccache)); | |
254 | } | |
255 | #endif /* !HEIMDAL */ | |
256 | #endif /* KRB5 */ |