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1 | /* $OpenBSD: auth-krb5.c,v 1.18 2006/05/06 08:35:40 dtucker 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 "ssh.h" | |
34 | #include "ssh1.h" | |
35 | #include "packet.h" | |
36 | #include "xmalloc.h" | |
37 | #include "log.h" | |
38 | #include "servconf.h" | |
39 | #include "uidswap.h" | |
40 | #include "auth.h" | |
41 | ||
42 | #ifdef KRB5 | |
43 | #include <errno.h> | |
44 | #include <krb5.h> | |
45 | ||
46 | extern ServerOptions options; | |
47 | ||
48 | static int | |
49 | krb5_init(void *context) | |
50 | { | |
51 | Authctxt *authctxt = (Authctxt *)context; | |
52 | krb5_error_code problem; | |
53 | ||
54 | if (authctxt->krb5_ctx == NULL) { | |
55 | problem = krb5_init_context(&authctxt->krb5_ctx); | |
56 | if (problem) | |
57 | return (problem); | |
58 | } | |
59 | return (0); | |
60 | } | |
61 | ||
62 | int | |
63 | auth_krb5_password(Authctxt *authctxt, const char *password) | |
64 | { | |
65 | #ifndef HEIMDAL | |
66 | krb5_creds creds; | |
67 | krb5_principal server; | |
68 | #endif | |
69 | krb5_error_code problem; | |
70 | krb5_ccache ccache = NULL; | |
71 | int len; | |
72 | ||
73 | temporarily_use_uid(authctxt->pw); | |
74 | ||
75 | problem = krb5_init(authctxt); | |
76 | if (problem) | |
77 | goto out; | |
78 | ||
79 | problem = krb5_parse_name(authctxt->krb5_ctx, authctxt->pw->pw_name, | |
80 | &authctxt->krb5_user); | |
81 | if (problem) | |
82 | goto out; | |
83 | ||
84 | #ifdef HEIMDAL | |
85 | problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_mcc_ops, &ccache); | |
86 | if (problem) | |
87 | goto out; | |
88 | ||
89 | problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache, | |
90 | authctxt->krb5_user); | |
91 | if (problem) | |
92 | goto out; | |
93 | ||
94 | restore_uid(); | |
95 | ||
96 | problem = krb5_verify_user(authctxt->krb5_ctx, authctxt->krb5_user, | |
97 | ccache, password, 1, NULL); | |
98 | ||
99 | temporarily_use_uid(authctxt->pw); | |
100 | ||
101 | if (problem) | |
102 | goto out; | |
103 | ||
104 | problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_fcc_ops, | |
105 | &authctxt->krb5_fwd_ccache); | |
106 | if (problem) | |
107 | goto out; | |
108 | ||
109 | problem = krb5_cc_copy_cache(authctxt->krb5_ctx, ccache, | |
110 | authctxt->krb5_fwd_ccache); | |
111 | krb5_cc_destroy(authctxt->krb5_ctx, ccache); | |
112 | ccache = NULL; | |
113 | if (problem) | |
114 | goto out; | |
115 | ||
116 | #else | |
117 | problem = krb5_get_init_creds_password(authctxt->krb5_ctx, &creds, | |
118 | authctxt->krb5_user, (char *)password, NULL, NULL, 0, NULL, NULL); | |
119 | if (problem) | |
120 | goto out; | |
121 | ||
122 | problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL, | |
123 | KRB5_NT_SRV_HST, &server); | |
124 | if (problem) | |
125 | goto out; | |
126 | ||
127 | restore_uid(); | |
128 | problem = krb5_verify_init_creds(authctxt->krb5_ctx, &creds, server, | |
129 | NULL, NULL, NULL); | |
130 | krb5_free_principal(authctxt->krb5_ctx, server); | |
131 | temporarily_use_uid(authctxt->pw); | |
132 | if (problem) | |
133 | goto out; | |
134 | ||
135 | if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user, | |
136 | authctxt->pw->pw_name)) { | |
137 | problem = -1; | |
138 | goto out; | |
139 | } | |
140 | ||
141 | problem = ssh_krb5_cc_gen(authctxt->krb5_ctx, &authctxt->krb5_fwd_ccache); | |
142 | if (problem) | |
143 | goto out; | |
144 | ||
145 | problem = krb5_cc_initialize(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache, | |
146 | authctxt->krb5_user); | |
147 | if (problem) | |
148 | goto out; | |
149 | ||
150 | problem= krb5_cc_store_cred(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache, | |
151 | &creds); | |
152 | if (problem) | |
153 | goto out; | |
154 | #endif | |
155 | ||
156 | authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache); | |
157 | ||
158 | len = strlen(authctxt->krb5_ticket_file) + 6; | |
159 | authctxt->krb5_ccname = xmalloc(len); | |
160 | snprintf(authctxt->krb5_ccname, len, "FILE:%s", | |
161 | authctxt->krb5_ticket_file); | |
162 | ||
163 | #ifdef USE_PAM | |
164 | if (options.use_pam) | |
165 | do_pam_putenv("KRB5CCNAME", authctxt->krb5_ccname); | |
166 | #endif | |
167 | ||
168 | out: | |
169 | restore_uid(); | |
170 | ||
171 | if (problem) { | |
172 | if (ccache) | |
173 | krb5_cc_destroy(authctxt->krb5_ctx, ccache); | |
174 | ||
175 | if (authctxt->krb5_ctx != NULL && problem!=-1) | |
176 | debug("Kerberos password authentication failed: %s", | |
177 | krb5_get_err_text(authctxt->krb5_ctx, problem)); | |
178 | else | |
179 | debug("Kerberos password authentication failed: %d", | |
180 | problem); | |
181 | ||
182 | krb5_cleanup_proc(authctxt); | |
183 | ||
184 | if (options.kerberos_or_local_passwd) | |
185 | return (-1); | |
186 | else | |
187 | return (0); | |
188 | } | |
189 | return (authctxt->valid ? 1 : 0); | |
190 | } | |
191 | ||
192 | void | |
193 | krb5_cleanup_proc(Authctxt *authctxt) | |
194 | { | |
195 | debug("krb5_cleanup_proc called"); | |
196 | if (authctxt->krb5_fwd_ccache) { | |
197 | krb5_cc_destroy(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache); | |
198 | authctxt->krb5_fwd_ccache = NULL; | |
199 | } | |
200 | if (authctxt->krb5_user) { | |
201 | krb5_free_principal(authctxt->krb5_ctx, authctxt->krb5_user); | |
202 | authctxt->krb5_user = NULL; | |
203 | } | |
204 | if (authctxt->krb5_ctx) { | |
205 | krb5_free_context(authctxt->krb5_ctx); | |
206 | authctxt->krb5_ctx = NULL; | |
207 | } | |
208 | } | |
209 | ||
210 | #ifndef HEIMDAL | |
211 | krb5_error_code | |
212 | ssh_krb5_cc_gen(krb5_context ctx, krb5_ccache *ccache) { | |
213 | int tmpfd, ret; | |
214 | char ccname[40]; | |
215 | mode_t old_umask; | |
216 | ||
217 | ret = snprintf(ccname, sizeof(ccname), | |
218 | "FILE:/tmp/krb5cc_%d_XXXXXXXXXX", geteuid()); | |
219 | if (ret < 0 || (size_t)ret >= sizeof(ccname)) | |
220 | return ENOMEM; | |
221 | ||
222 | old_umask = umask(0177); | |
223 | tmpfd = mkstemp(ccname + strlen("FILE:")); | |
224 | umask(old_umask); | |
225 | if (tmpfd == -1) { | |
226 | logit("mkstemp(): %.100s", strerror(errno)); | |
227 | return errno; | |
228 | } | |
229 | ||
230 | if (fchmod(tmpfd,S_IRUSR | S_IWUSR) == -1) { | |
231 | logit("fchmod(): %.100s", strerror(errno)); | |
232 | close(tmpfd); | |
233 | return errno; | |
234 | } | |
235 | close(tmpfd); | |
236 | ||
237 | return (krb5_cc_resolve(ctx, ccname, ccache)); | |
238 | } | |
239 | #endif /* !HEIMDAL */ | |
240 | #endif /* KRB5 */ |