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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 | ||
82 | temporarily_use_uid(authctxt->pw); | |
83 | ||
84 | problem = krb5_init(authctxt); | |
85 | if (problem) | |
86 | goto out; | |
87 | ||
88 | problem = krb5_parse_name(authctxt->krb5_ctx, authctxt->pw->pw_name, | |
89 | &authctxt->krb5_user); | |
90 | if (problem) | |
91 | goto out; | |
92 | ||
93 | #ifdef HEIMDAL | |
94 | problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_mcc_ops, &ccache); | |
95 | if (problem) | |
96 | goto out; | |
97 | ||
98 | problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache, | |
99 | authctxt->krb5_user); | |
100 | if (problem) | |
101 | goto out; | |
102 | ||
103 | restore_uid(); | |
104 | ||
105 | problem = krb5_verify_user(authctxt->krb5_ctx, authctxt->krb5_user, | |
106 | ccache, password, 1, NULL); | |
107 | ||
108 | temporarily_use_uid(authctxt->pw); | |
109 | ||
110 | if (problem) | |
111 | goto out; | |
112 | ||
113 | problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_fcc_ops, | |
114 | &authctxt->krb5_fwd_ccache); | |
115 | if (problem) | |
116 | goto out; | |
117 | ||
118 | problem = krb5_cc_copy_cache(authctxt->krb5_ctx, ccache, | |
119 | authctxt->krb5_fwd_ccache); | |
120 | krb5_cc_destroy(authctxt->krb5_ctx, ccache); | |
121 | ccache = NULL; | |
122 | if (problem) | |
123 | goto out; | |
124 | ||
125 | #else | |
126 | problem = krb5_get_init_creds_password(authctxt->krb5_ctx, &creds, | |
127 | authctxt->krb5_user, (char *)password, NULL, NULL, 0, NULL, NULL); | |
128 | if (problem) | |
129 | goto out; | |
130 | ||
131 | problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL, | |
132 | KRB5_NT_SRV_HST, &server); | |
133 | if (problem) | |
134 | goto out; | |
135 | ||
136 | restore_uid(); | |
137 | problem = krb5_verify_init_creds(authctxt->krb5_ctx, &creds, server, | |
138 | NULL, NULL, NULL); | |
139 | krb5_free_principal(authctxt->krb5_ctx, server); | |
140 | temporarily_use_uid(authctxt->pw); | |
141 | if (problem) | |
142 | goto out; | |
143 | ||
144 | if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user, | |
145 | authctxt->pw->pw_name)) { | |
146 | problem = -1; | |
147 | goto out; | |
148 | } | |
149 | ||
150 | problem = ssh_krb5_cc_gen(authctxt->krb5_ctx, &authctxt->krb5_fwd_ccache); | |
151 | if (problem) | |
152 | goto out; | |
153 | ||
154 | problem = krb5_cc_initialize(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache, | |
155 | authctxt->krb5_user); | |
156 | if (problem) | |
157 | goto out; | |
158 | ||
159 | problem= krb5_cc_store_cred(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache, | |
160 | &creds); | |
161 | if (problem) | |
162 | goto out; | |
163 | #endif | |
164 | ||
165 | authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache); | |
166 | ||
167 | len = strlen(authctxt->krb5_ticket_file) + 6; | |
168 | authctxt->krb5_ccname = xmalloc(len); | |
169 | #ifdef USE_CCAPI | |
170 | snprintf(authctxt->krb5_ccname, len, "API:%s", | |
171 | authctxt->krb5_ticket_file); | |
172 | #else | |
173 | snprintf(authctxt->krb5_ccname, len, "FILE:%s", | |
174 | authctxt->krb5_ticket_file); | |
175 | #endif | |
176 | ||
177 | #ifdef USE_PAM | |
178 | if (options.use_pam) | |
179 | do_pam_putenv("KRB5CCNAME", authctxt->krb5_ccname); | |
180 | #endif | |
181 | ||
182 | out: | |
183 | restore_uid(); | |
184 | ||
185 | if (problem) { | |
186 | if (ccache) | |
187 | krb5_cc_destroy(authctxt->krb5_ctx, ccache); | |
188 | ||
189 | if (authctxt->krb5_ctx != NULL && problem!=-1) | |
190 | debug("Kerberos password authentication failed: %s", | |
191 | krb5_get_err_text(authctxt->krb5_ctx, problem)); | |
192 | else | |
193 | debug("Kerberos password authentication failed: %d", | |
194 | problem); | |
195 | ||
196 | krb5_cleanup_proc(authctxt); | |
197 | ||
198 | if (options.kerberos_or_local_passwd) | |
199 | return (-1); | |
200 | else | |
201 | return (0); | |
202 | } | |
203 | return (authctxt->valid ? 1 : 0); | |
204 | } | |
205 | ||
206 | void | |
207 | krb5_cleanup_proc(Authctxt *authctxt) | |
208 | { | |
209 | debug("krb5_cleanup_proc called"); | |
210 | if (authctxt->krb5_fwd_ccache) { | |
211 | krb5_cc_destroy(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache); | |
212 | authctxt->krb5_fwd_ccache = NULL; | |
213 | } | |
214 | if (authctxt->krb5_user) { | |
215 | krb5_free_principal(authctxt->krb5_ctx, authctxt->krb5_user); | |
216 | authctxt->krb5_user = NULL; | |
217 | } | |
218 | if (authctxt->krb5_ctx) { | |
219 | krb5_free_context(authctxt->krb5_ctx); | |
220 | authctxt->krb5_ctx = NULL; | |
221 | } | |
222 | } | |
223 | ||
224 | #ifndef HEIMDAL | |
225 | krb5_error_code | |
226 | ssh_krb5_cc_gen(krb5_context ctx, krb5_ccache *ccache) { | |
227 | int ret; | |
228 | char ccname[40]; | |
229 | mode_t old_umask; | |
230 | #ifdef USE_CCAPI | |
231 | char cctemplate[] = "API:krb5cc_%d"; | |
232 | #else | |
233 | char cctemplate[] = "FILE:/tmp/krb5cc_%d_XXXXXXXXXX"; | |
234 | int tmpfd; | |
235 | #endif | |
236 | ||
237 | ret = snprintf(ccname, sizeof(ccname), | |
238 | cctemplate, geteuid()); | |
239 | if (ret < 0 || (size_t)ret >= sizeof(ccname)) | |
240 | return ENOMEM; | |
241 | ||
242 | #ifndef USE_CCAPI | |
243 | old_umask = umask(0177); | |
244 | tmpfd = mkstemp(ccname + strlen("FILE:")); | |
245 | umask(old_umask); | |
246 | if (tmpfd == -1) { | |
247 | logit("mkstemp(): %.100s", strerror(errno)); | |
248 | return errno; | |
249 | } | |
250 | ||
251 | if (fchmod(tmpfd,S_IRUSR | S_IWUSR) == -1) { | |
252 | logit("fchmod(): %.100s", strerror(errno)); | |
253 | close(tmpfd); | |
254 | return errno; | |
255 | } | |
256 | close(tmpfd); | |
257 | #endif | |
258 | ||
259 | return (krb5_cc_resolve(ctx, ccname, ccache)); | |
260 | } | |
261 | #endif /* !HEIMDAL */ | |
262 | #endif /* KRB5 */ |